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JP2008096113

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2008096113
To provide an obstacle detection device capable of improving the design and securing desired
directivity. An obstacle detection device (100) having an ultrasonic sensor (120) including an
ultrasonic transducer (121) attached to an inner surface (141a) of a wall member (140), and
transmitting or receiving ultrasonic waves through the wall member (140). A plurality of rigidity
changes that make the rigidity of the wall member 140 different from the adjacent inner side in
the separating direction with respect to the contact portion 142 on the inner surface 141a of the
wall member 140 excluding the contact portion 142 with the vibration portion 122a of the
ultrasonic sensor 120. The parts 143 and 144 are provided. [Selected figure] Figure 1
Obstacle detection device
[0001]
The present invention relates to an obstacle detection device in which an ultrasonic sensor
including an ultrasonic transducer is attached to an inner surface of a wall member, and
transmitting and / or receiving ultrasonic waves through the wall member.
[0002]
BACKGROUND Conventionally, an obstacle detection device that detects an obstacle located
around a vehicle using, for example, an ultrasonic sensor is known.
For example, in an obstacle detection device provided with an ultrasonic sensor described in
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Patent Document 1, a hole is provided in a bumper of a vehicle, and the head of the ultrasonic
sensor is exposed so as to be flush with the outer surface of the bumper from the hole. .
However, the obstacle detection device having such a configuration is not preferable in terms of
design because the head of the ultrasonic sensor is exposed to the outside of the vehicle.
[0003]
To address this problem, for example, in the obstacle detection device disclosed in Patent
Document 2, a recess is provided on the back side of the vehicle bumper, and an ultrasonic
vibration sensor is accommodated in the recess to make the sensor invisible from the outside. ,
To improve the design. JP, 2004-264264, A JP, 10-123236, A
[0004]
By the way, in the obstacle detection device described in Patent Document 2, an ultrasonic sensor
formed by integrally integrating a circular plate-like ceramic (ultrasonic transducer) on a metal
base is larger in the planar direction of the bumper than the ceramic. The ceramic outer surface
is attached in direct contact with the bottom of the provided recess. Therefore, the vibration (socalled unnecessary vibration) is easily transmitted to the periphery of the contact portion with
the ultrasonic sensor (ceramic) in the bumper, the vibration of the bumper spreads over a wide
range, and the directivity becomes irregular. This is considered to be caused by the interference
caused by the different phases at each part due to the vibration being spread over a wide area.
The present invention has been made in view of the above points, and improves the designability,
and An object of the present invention is to provide an obstacle detection device capable of
securing desired directivity.
[0005]
In order to achieve the above object, the invention according to claim 1 comprises an ultrasonic
sensor including an ultrasonic transducer attached to the inner surface of a wall member, and
transmits or receives ultrasonic waves through the wall member. The wall member is a wave-like
obstacle detection device, and the wall member has the rigidity of the inner side (contact portion
side) adjacent to the contact portion and the rigidity of the wall member on the inner surface
excluding the contact portion with the vibration portion of the ultrasonic sensor. And a plurality
of stiffness change portions that differ from each other.
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[0006]
As described above, according to the present invention, the ultrasonic sensor is attached to the
inner surface of the wall member, and the ultrasonic wave is transmitted or received via the wall
member.
Therefore, since the ultrasonic sensor can not be seen from the outside of the wall member, the
design can be improved. The transmission or reception of ultrasonic waves means at least one of
transmission and reception of ultrasonic waves (transmission only, reception only, transmission,
or reception).
[0007]
Further, by providing the rigidity change portion on the inner surface of the wall member
excluding the portion (contact portion) where the vibration portion of the ultrasonic sensor
contacts, the rigidity of the portion of the wall member having the rigidity change portion can be
Side) is different. Thus, when the rigidity difference is provided, the higher one is less likely to
vibrate and the lower one is more likely to be vibrated. Therefore, it is possible to reduce the
transmission of vibration (hereinafter referred to as unnecessary vibration) to the outside (aside
from the contact portion) than the rigidity change portion. In the present invention, in particular,
since the plurality of rigidity change portions are provided in the direction away from the contact
portion, unnecessary vibration can be effectively reduced. As described above, the main
transmission range of the ultrasonic waves (vibration) in the wall member can be narrowed
(defined as a predetermined range) by the rigidity change part, so that desired directivity can be
secured.
[0008]
The number of ultrasonic sensors attached to the wall member is not particularly limited.
Stiffness change parts may be provided corresponding to individual sensors. In the configuration
in which a plurality of ultrasonic sensors are juxtaposed with the wall member, the rigidity
change portion can also reduce unnecessary vibration from the adjacent ultrasonic sensors.
[0009]
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As an ultrasonic sensor, as described in claim 2, a structure in which the ultrasonic transducer is
contact-fixed to the inner surface of the bottom surface of the housing as the housing and the
outer surface of the bottom surface is in contact with the wall member At least a part of the
bottom portion of the structure can function as a vibrating portion of the ultrasonic sensor in
contact with the wall member. According to the third aspect of the present invention, it is also
possible to adopt a configuration in which the ultrasonic transducer is not accommodated in the
housing and contacts the wall member.
[0010]
In the invention according to claim 2, for example, according to claim 4, a part of the outer
surface of the bottom portion is provided with a convex ultrasonic wave transmission portion as
a contact portion with the wall member. Is preferred. According to this, the transmission range of
the ultrasonic wave (vibration) is narrowed between the ultrasonic transducer and the wall
member by the convex ultrasonic wave transmission part (that is, the projection) provided on a
part of the outer surface of the bottom part (It can be defined in a predetermined range).
Therefore, in combination with the effect of the rigidity change portion, desired directivity can be
more easily ensured.
[0011]
In the fourth aspect of the invention, as in the fifth aspect, the shape of the contact surface of the
ultrasonic wave transmitting portion may be different from the shape of the bottom portion in
the plane direction of the wall member. According to this, it becomes possible to cope with
various directivity depending on the shape of the ultrasonic wave transmission unit.
[0012]
In the invention according to claim 2 or 3, for example, according to claim 6, a convex ultrasonic
wave transmitting portion (i.e., a projection) as a contact portion with the ultrasonic sensor in the
wall member. , And at least one of the shape and the area may be different between the contact
surface of the ultrasonic wave transmission unit as the contact portion and the contact surface of
the ultrasonic sensor. As described above, the transmission range of the ultrasonic wave
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(vibration) is narrowed between the ultrasonic transducer and the wall member also by providing
the convex ultrasonic wave transmission part on the wall member side. be able to. Therefore, in
combination with the effect of the rigidity change portion, desired directivity can be more easily
ensured.
[0013]
In the second aspect of the invention, as described in the seventh aspect, the acoustic impedance
and the ultrasonic wave of the wall member are in contact with the wall member and the
ultrasonic vibrator at a part of the bottom surface of the housing. An ultrasonic wave
transmission unit made of a material having an acoustic impedance intermediate to that of the
vibrator may be provided, and ultrasonic waves may be transmitted through the ultrasonic wave
transmission unit and the wall member.
[0014]
Ultrasonic waves have a characteristic that the amount of reflection between members increases
as the difference in impedance increases between members with different acoustic impedances.
On the other hand, according to the seventh aspect of the present invention, since the ultrasonic
wave transmission part is provided in a part of the bottom part, the acoustic impedance can be
set appropriately. In addition, since it is necessary to satisfy the characteristics such as rigidity
required for fixing the ultrasonic transducer and attaching to the wall member, the housing
should select an optimal material for transmitting ultrasonic waves. Is difficult. As a result, at the
bottom portion made of a casing material around the ultrasonic wave transmission portion, the
amount of ultrasonic wave transmission is lower than that of the ultrasonic wave transmission
portion. Therefore, the main transmission range of the ultrasonic waves (vibration) at the bottom
of the housing can be narrowed to the range corresponding to the ultrasonic wave transmission
portion. And it can be made easier to ensure desired directivity, in combination with the effect of
the rigidity change part. In the ultrasonic wave transmission unit according to claims 4 and 5, the
configuration according to claim 7 may be applied.
[0015]
According to the seventh aspect of the present invention, as described in the eighth aspect, the
acoustic impedance of the ultrasonic wave transmitting portion is higher than the acoustic
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impedance of the bottom surface portion of the casing around the ultrasonic wave transmitting
portion. It is good to set it as the intermediate value of the acoustic impedance of a child, and the
acoustic impedance of a wall member. According to this, the transmission amount of the
ultrasonic wave in the ultrasonic wave transmission unit can be reliably made larger than the
transmission amount of the ultrasonic wave in the surrounding housing portion (bottom surface
portion).
[0016]
In the invention according to any one of claims 4 to 8, as described in claim 9, in the ultrasonic
wave transmitting portion, the lengths in the two axial directions orthogonal to each other in the
plane direction of the wall member are mutually different. It may be a different configuration.
According to this, even if the directivity is different in the horizontal direction and the vertical
direction with respect to the ground (for example, having directivity), desired directivity can be
secured.
[0017]
For example, as described in claim 10, it is preferable that a groove portion provided on the inner
surface excluding the contact portion is included as the rigidity change portion. The rigidity of
the wall member at the part having the groove is lower than the rigidity of the wall member
around the groove. Therefore, unnecessary vibration transmitted from the groove to the outer
peripheral side of the groove (aside from the contact portion) is reduced, and the range in which
the wall member is easily vibrated can be defined. For example, as described in claim 11, when
the groove includes a groove which is concave with respect to the contact portion and provided
adjacent to the outer periphery of the contact portion, the contact portion is compared with the
configuration without the groove. Can be made easier to vibrate. As a result, unnecessary
vibration transmitted to the periphery of the contact area can be reduced.
[0018]
In addition, as the rigidity change portion, as described in claim 12, a configuration including a
protrusion provided on the inner surface excluding the contact portion may be employed. The
rigidity of the wall member at the portion having the protrusion is higher than the rigidity of the
wall member around the protrusion. Therefore, the unnecessary vibration transmitted to the
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outer peripheral side (the separating side with respect to the contact portion) than the projection
can be reduced by at least the restraint effect by the rigidity improvement. The protrusions not
only enhance the rigidity of the wall member of the portion having the protrusions, but
depending on the configuration, the protrusions themselves are elastically deformed to absorb
the energy of the unnecessary vibration and perform the function of reducing the unnecessary
vibration. It can also be done.
[0019]
In the invention according to claim 12, for example, as described in claim 13, the rigidity
changing unit may be configured to include a plurality of protrusions. Preferably, the plurality of
protrusions are provided close to each other in the direction away from the vibration surface.
When one large protrusion is provided in the predetermined range, the rigidity of the wall
member in the predetermined range can be enhanced (the restraint effect can be enhanced) as
compared to providing a plurality of protrusions. However, due to the large volume, if the
projection is provided integrally with the wall member, for example, by injection molding, a sink
may occur to a certain degree as seen from the outer surface of the wall member. On the other
hand, according to the configuration of claim 14, since the plurality of projections are provided
in the predetermined range, the volume of each projection becomes small, and the risk of sink
marks and / or the degree of sink marks is reduced. can do. Moreover, although it is inferior to
one big projection part, since the several projection part is provided, the rigidity of the wall
member in a predetermined range can be improved. In addition, since the thickness of each
protrusion is smaller than that of one protrusion in the plane direction of the wall member, an
effect by elastic deformation can be expected.
[0020]
In the invention as set forth in claim 13 or 14, according to claim 15, in the plurality of
protrusions, the thickness of at least one protrusion in the thickness direction (the direction
orthogonal to the surface direction) of the wall member The height (i.e., the projection height)
may be different from the thickness (projection height) of the other projections. When all the
projection heights of the plurality of projections are equal, each projection resonates with the
unnecessary vibration of the predetermined frequency, and the unnecessary vibration can be
efficiently reduced. However, for example, when the physical property (for example, Young's
modulus) of the wall member changes due to a temperature change, the wavelength of
unnecessary vibration changes even if the voltage applied to the ultrasonic transducer is the
same. For example, when the temperature is low, the Young's modulus is increased, the wall
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member becomes hard, and the wavelength of unnecessary vibration becomes long. On the other
hand, as described in claim 15, when the protrusion height of at least one protrusion is made
different from the other (that is, the resonance frequency of the protrusion is shifted), the
unnecessary vibration is caused by the temperature change. Even if the frequency changes, the
unnecessary vibration can be reduced by any of the protrusions. In addition, even in the case of
transmitting and / or receiving a plurality of ultrasonic waves having different frequencies, it is
possible to efficiently reduce each unnecessary vibration.
[0021]
In the invention according to any one of claims 12 to 15, as described in claim 16, the thickness
(protrusion height) of the projection is the thickness excluding the projection of the portion
having the projection. It is good to be set as (The thickness of the base of a wall member) or
more. According to this, the resonance length can be easily secured, and unnecessary vibration
can be efficiently reduced.
[0022]
In the invention according to any one of claims 12 to 16, as described in claim 17, the thickness
(i.e., the width) of the protrusion in the planar direction of the wall member is the protrusion in
the thickness direction of the wall member It is good to set it as the thickness (thickness of the
base of a wall member) except the projection part of the portion which has a part or less.
According to this, the rigidity of the projection itself is reduced, and the projection is easily
elastically deformed when the unnecessary vibration is transmitted. Also, the risk of sink marks
and / or the extent of sink marks can be reduced.
[0023]
In the invention according to any one of claims 12 to 17, as described in claim 18, the projection
may be integrally formed using the same material as the wall member. According to this, the
manufacturing process can be simplified.
[0024]
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In the invention as set forth in any one of claims 1 to 18, it is preferable that at least one of the
plurality of rigidity change parts be annularly provided to surround the contact portion. .
Although the unnecessary vibration radially spreads from the contact portion to the periphery
thereof, the escape portion of the unnecessary vibration can be eliminated and the unnecessary
vibration can be reduced.
[0025]
In the invention according to claim 20, as described in claim 19, it is preferable that at least one
of the plurality of rigidity change parts be provided annularly along the outer peripheral shape of
the contact portion. According to this, since the distance between the contact portion and the
rigidity change portion is uniform, it is possible to easily secure directivity according to the shape
of the contact portion, for example, as in the above-described ultrasonic transmission unit.
[0026]
In the invention according to claim 19 or claim 20, as described in claim 21, it is preferable that
the rigidity change portion at a position closest to the contact portion be provided in an annular
shape. The closer to the contact portion, the larger the energy of the unnecessary vibration, and
the larger the effect of reducing the unnecessary vibration by the rigidity change part. Therefore,
according to the invention described in claim 21, the main transmission range of the ultrasonic
waves (vibrations) in the wall member can be further narrowed. More preferably, as described in
claim 22, it is more effective to provide the rigidity change portion at a position closest to the
contact site so as to be adjacent to the periphery of the contact site.
[0027]
In the invention according to any one of claims 19 to 22, as described in claim 23, the plurality
of rigidity change portions are provided concentrically with respect to the contact portion, and
the contact portion is formed by the plurality of rigidity change portions. With the configuration
surrounded by multiples, unnecessary vibration can be further reduced.
[0028]
In the invention described in any one of claims 19 to 23, as described in claim 24, all the rigidity
change parts may be provided in an annular shape.
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[0029]
In the invention according to any one of claims 1 to 24, as described in claim 25, the inner
surface of the wall member excluding the contact portion with the ultrasonic sensor has a larger
attenuation coefficient than the wall member. A damping member made of a material may be
stacked and arranged.
According to this, the energy of the unnecessary vibration can be absorbed by the damping
member, and the unnecessary vibration transmitted to the periphery than the arrangement
position of the damping member can be reduced.
[0030]
The arrangement of the attenuation members is not particularly limited as long as the
arrangement satisfies the conditions described in claim 25. However, since the attenuation
members have a large attenuation coefficient, they are difficult to be arranged in a narrow range.
Therefore, as described in the twenty-sixth aspect, it may be provided on the outer peripheral
side (the separation side with respect to the contact portion) than the rigidity change part.
[0031]
Hereinafter, embodiments of the present invention will be described based on the drawings. First
Embodiment FIG. 1 is a view showing a schematic configuration of an obstacle detection device
according to a first embodiment of the present invention, in which (a) is a plan view seen from
the inner surface side, and (b) is It is sectional drawing which follows the II line of a). FIG. 2 is a
schematic view for explaining unnecessary vibration reduction by the groove portion. FIG. 3 is a
view showing the effect of the groove portion. FIG. 4 is a schematic view for explaining
unnecessary vibration reduction by the projection. FIG. 5 is a diagram showing simulation results
by FEM. FIG. 6 is a diagram showing the effect of the protrusion. In FIG. 1A, for the sake of
convenience, in the ultrasonic sensor, only the outer peripheral end of the outer surface of the
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bottom surface portion of the housing is shown by a broken line. Further, in FIG. 1 (b), the point
of change of rigidity in the wall member is indicated by an alternate long and short dash line
arrow only for one region with respect to the contact portion with the ultrasonic sensor for the
sake of convenience.
[0032]
As shown in FIG. 1B, the obstacle detection device 100 according to the present embodiment has
the ultrasonic sensor 120 attached to the inner surface 141a of the wall member 140, and
includes the wall member 140 as a vibration transmission path. The ultrasonic sensor 120
transmits an ultrasonic wave and / or receives an ultrasonic wave reflected by an obstacle as a
main part, and / or a case that accommodates the ultrasonic wave 121. Body 122 and is
included.
[0033]
As the ultrasonic transducer 121, for example, a piezoelectric transducer made of a piezoelectric
ceramic such as PZT or barium titanate as a sintered body can be employed. In this embodiment,
when a drive signal is applied, distortion occurs due to dielectric polarization, and a piezoelectric
vibrator made of PZT is used which vibrates in the longitudinal direction (thickness direction) to
generate an ultrasonic wave. In the present embodiment, one ultrasonic transducer 121 is
configured to double as transmitting and receiving ultrasonic waves.
[0034]
An electrode (not shown) is formed on the surface of the ultrasonic transducer 121, and a lead
123 is electrically connected to the electrode. In the present embodiment, as shown in FIG. 1B,
one lead 123 is connected to the inner surface of the housing 122 electrically connected to the
electrode. Then, the lead 123 vibrates the ultrasonic transducer 121 to output a drive signal for
generating an ultrasonic wave, or the ultrasonic wave is transmitted to the ultrasonic transducer
121 and distortion is generated in the ultrasonic transducer 121. When it occurs, it is electrically
connected to the circuit board 124 on which a processing circuit for inputting a voltage signal
generated by the piezoelectric effect is formed. That is, the obstacle detection device 100
including the ultrasonic sensor 120 determines the distance and direction to the obstacle existing
around the vehicle based on, for example, the time from transmission to reception of the
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ultrasonic wave, the phase difference of the reception signal, etc. It can be calculated.
[0035]
The housing 122 is provided in a bottomed cylindrical shape, for example, using aluminum or a
synthetic resin as a constituent material (in the present embodiment, the cylinder inner surface
of the synthetic resin is metal-coated) in order to accommodate one ultrasonic transducer 121
respectively. ing. And as shown in FIG.1 (b), the ultrasonic transducer | vibrator 121 is installed
in the inner surface of the bottom face part 122a (for example, adhesion | attachment fixation).
That is, the bottom surface portion 122a in which the ultrasonic transducer 121 is disposed
plays a role as a diaphragm, and the outer surface of the bottom surface portion 122a is a
vibration surface (a vibration portion of the ultrasonic sensor 120 shown in the claims). . In the
present embodiment, the outer surface of the bottom surface portion 122a as a vibrating surface
is, with respect to the ground, in the plane direction of the wall member 140 (the direction
orthogonal to the ground) as shown by a broken line in FIG. It has a flat rectangular shape which
is longer in the vertical direction than in the horizontal direction. However, in the present
embodiment, the wall member 140 is provided with a convex ultrasonic wave transmission unit
142 (details will be described later) for defining directivity. As described above, in the
configuration including the ultrasonic wave transmission unit 142, the shape of the outer surface
of the bottom portion 122a is not particularly limited in order to define directivity.
[0036]
Further, in the housing 122, as shown in FIG. 1B, the sound absorbing material 125 is disposed
around the ultrasonic transducer 121 except for the contact portion with the inner surface of the
bottom surface portion 122a. The sound absorbing material 125 is for absorbing unnecessary
ultrasonic waves radiated into the housing 122 by the expansion and contraction of the
ultrasonic transducer 121 and the vibration of the bottom surface portion 122 a of the housing
122, for example, silicon It is comprised by the material excellent in sound absorption
performance, such as a sponge. Note that reference numeral 122b shown in FIG. 1 (b) is a
stopper provided in the housing 122 for fixing the sound absorbing material 125 and the circuit
board 124, and reference numeral 126 indicates the circuit board 124 and the outside (for
example, A connector for connecting to a provided control unit for performing notification
processing control, travel control and the like, reference numeral 127 is a sealing material for
sealing the inside of the housing 122 in an airtight manner.
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[0037]
As described above, in the ultrasonic sensor 120 according to the present embodiment, since the
housing 122 is hermetically sealed, the ultrasonic transducer 121 is not exposed to the outside
air, and corrosion of the leads 123 and the like is prevented. Can. In addition, the fixing structure
to the inner surface 141a of the wall member 140 of the ultrasonic sensor 120 is employable as
long as the structure is not exposed to the outer surface 141b of the wall member 140. In the
present embodiment, as an example, the outer surface of the bottom surface portion 122a is
adhesively fixed to the inner surface 141a of the wall member 140.
[0038]
The wall member 140 is not particularly limited. Any material (material and thickness) suitable
for ultrasonic wave (vibration) transmission is applicable. In the present embodiment, a bumper
of a vehicle is employed as the wall member 140. That is, the obstacle detection device 100
according to the present embodiment is configured as a vehicle obstacle detection device that
detects an obstacle around the vehicle. In addition, although a bumper is synthetic resin molded
articles, such as urethane and a polypropylene, when it comprises as an obstacle detection
apparatus for vehicles, it is also possible to employ | adopt the metal plate which comprises a
vehicle body etc. as the wall member 140.
[0039]
A convex ultrasonic wave transmitting portion 142 is formed on the inner surface 141a of the
base material 141 made of synthetic resin that constitutes the wall member 140, corresponding
to the vibration site of the ultrasonic sensor 120 (the outer surface of the bottom surface portion
122a of the housing 122). (The broken line shown in FIG. 1 (b) is the boundary with the base
material 141). That is, the ultrasonic wave (vibration) is transmitted between the ultrasonic
sensor 120 (the ultrasonic transducer 121 and the bottom 122a of the housing 122) and the
wall member 140 through the ultrasonic wave transmitter 142. ing.
[0040]
The ultrasonic wave transmitting portion 142 is a columnar portion projecting from the inner
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surface 141 a of the base material 141, and in the plane direction of the wall member 140, the
contact surface of the ultrasonic wave transmitting portion 142 and the outer surface of the
bottom surface portion 122 a of the housing 122 At least one of the shape and the area is
configured to be different. That is, the main transmission range of the ultrasonic wave (vibration)
transmitted between the ultrasonic sensor 120 and the wall member 140 is narrowed (defined as
a predetermined range) by the ultrasonic wave transmission unit 142 There is. As shown in FIG.
1A, the ultrasonic wave transmission part 142 according to the present embodiment has a
smaller area than the outer surface of the bottom face part 122a as compared with the outer
surface of the bottom face part 122a, and the contact of the ultrasonic wave transmission part
142 It is configured to have a rectangular contact surface longer in the vertical direction than in
the horizontal direction so that the entire surface is entirely included in the contact area with the
outer surface of the bottom portion 122a. In addition, the shape of the contact surface of the
ultrasonic wave transmission part 142 is substantially the same as the outer surface of the
bottom part 122a. Further, the ultrasonic wave transmission unit 142 is integrally formed
(integrally formed) using the same material as the wall member 140.
[0041]
In addition, in the inner surface 141 a of the base 141 and at the site excluding the contact site
with the vibration site of the ultrasonic sensor 120 (the site where the ultrasonic wave
transmission portion 142 is formed), the direction away from the contact site (around the contact
site) In any one direction in which vibration is transmitted, a plurality of rigidity change portions
are provided to make the rigidity of the wall member 140 different from that on the adjacent
inner side (contact region side). As described above, when the rigidity change portion (a part
where the rigidity is different from the periphery) is provided, the higher rigidity is less likely to
vibrate and the lower rigidity is more easily vibrated due to the difference in rigidity. Therefore,
in the wall member 140, it is possible to reduce the vibration (unnecessary vibration) transmitted
to the outer peripheral side than the rigidity change portion (a portion having a rigidity different
from the periphery). In particular, unnecessary vibration can be effectively reduced by providing
a plurality of rigidity change portions in the direction away from the contact portion. In the
present embodiment, grooves 143 and protrusions 144 are included as the plurality of rigidity
change portions.
[0042]
The arrangement of the rigidity change portion is not particularly limited as long as it is a
portion other than the inner surface 141 a of the base material 141 except the contact portion
04-05-2019
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with the vibration portion of the ultrasonic sensor 120. Preferably, at least one of the plurality of
rigidity change portions may be annularly provided to surround the contact portion. With such a
configuration, it is possible to eliminate the unnecessary vibration escape region that radially
spreads from the contact region to the periphery, and the unnecessary vibration can be
effectively reduced. More preferably, it may be configured to be annularly provided along the
outer peripheral shape of the contact portion. With such a configuration, since the distance
between the contact portion and the rigidity change portion is uniform, directivity in accordance
with the shape of the contact portion (ultrasonic transmission portion 142) can be easily
ensured. More preferably, of the rigidity change portions, the rigidity change portion at a
position closest to the contact portion may be annularly provided. The closer to the contact
portion, the larger the energy of the unnecessary vibration, and the larger the effect of reducing
the unnecessary vibration by the rigidity change part. Therefore, with such a configuration, the
main transmission range of the ultrasonic wave (vibration) in the wall member 140 can be
narrowed. More preferably, when the configuration is provided adjacent to the outer periphery of
the contact portion, the main transmission range can be narrowed more effectively by the rigidity
change portion.
[0043]
The groove part 143 may be formed at the time of formation of the base material 141 which
constitutes the wall member 140, or may be formed by processing the formed base material 141.
The groove part 143 which concerns on this embodiment is simultaneously formed at the time of
base-material 141 formation which consists of resin.
[0044]
The rigidity of the wall member 140 (base material 141) of the portion where the groove portion
143 is provided is lower than the rigidity of the periphery of the groove portion 143, so the
portion where the groove portion 143 is provided is more easily deformed than the other
portions. For example, as shown in FIG. 2, when the groove portion 143 is provided so as to
sandwich the portion of the base member 141 including the contact portion with the ultrasonic
sensor 120 in the planar direction of the wall member 140, the outside of the groove portion
143 (contact Since the rigidity of the side away from the portion is higher than that of the groove
portion 143, the groove portion 143 becomes a so-called node when transmitting or receiving
ultrasonic waves, and the portion of the base material 141 sandwiched by the groove portion
143 easily vibrates ( Energy spent on vibration increases). Therefore, the vibration of the portion
of the base material 141 sandwiched by the groove portion 143 is increased as shown by, for
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example, an alternate long and short dash line, and as a result, the energy of the unnecessary
vibration transmitted to the outside of the groove portion 143 is reduced. It is considered to be
reduced. Alternatively, since the rigidity of the outer side (the separation side with respect to the
contact portion) of the groove portion 143 is higher than that of the groove portion 143,
unnecessary vibration is hardly transmitted to the outer portion of the groove portion 143, and
energy of unnecessary vibration is reflected. Therefore, it is considered that the energy of the
unnecessary vibration of the portion of the base member 141 including the groove portion 143
and the contact portion sandwiched by the outer portion of the groove portion 143 becomes
large, and the vibration becomes large as shown by an alternate long and short dash line in FIG.
Be In any case, when the groove portion 143 is provided, the range in which the wall member
140 easily vibrates (the main transmission range of the ultrasonic wave (vibration) in the wall
member 140) can be narrowed (defined as a predetermined range). Desired directivity can be
secured.
[0045]
In the present embodiment, as the groove portion 143, as shown in FIG. 1B, the side surface
(inner rigidity change point) on the inner side (contact area side) is adjacent to the outer
periphery of the contact area in the separating direction with respect to the contact area. It has
one annular groove. Further, not only the inner surface adjacent to the outer periphery of the
contact area but also the planar shape of the outer surface (outside rigid change point) which is
the opposite surface is a shape along the outer periphery of the contact area (that is, the groove
143 has a constant width) . That is, the range of easy vibration defined by the groove portion
143 is narrowed as much as possible, and the range of easy vibration is made the same shape as
the ultrasonic wave transmission part 142.
[0046]
In the configuration in which the groove portion 143 is provided with the portion including the
contact portion interposed therebetween, it is considered that the portion including the groove
portion 143 vibrates with the outer surface of the groove portion 143 as a boundary. It is
preferable to set it as the predetermined | prescribed shape according to directivity. For example,
even if the inner side surface is formed in a plane circular shape and the outer surface is formed
in the same plane rectangular shape as the ultrasonic wave transmission unit 142, an effect
according to the configuration shown in the present embodiment can be expected.
04-05-2019
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[0047]
The number of grooves 143 is not limited to one. By providing a plurality of annular grooves
143, the contact portion may be surrounded in multiple layers. However, as described above, the
groove 143 is characterized in that by providing the groove 143, a portion with low rigidity is
formed in a part of the wall member 140, thereby defining a range where vibration is easy.
Therefore, if there are a plurality of locations with low rigidity, the range susceptible to vibration
is rather broad, and the directivity may be irregular. Therefore, as shown in the present
embodiment, the number of grooves 143 provided in the direction away from the contact site
may be one. In addition, the area is smaller than the outer surface of the bottom surface portion
122a with respect to the outer surface of the bottom surface portion 122a, and the entire contact
surface of the ultrasonic wave transmission portion 142 is entirely included in the contact range
with the outer surface of the bottom surface portion 122a. Since the sound wave transmission
portion 142 is configured, the groove portion 143 is easier to configure in the vicinity of the
contact portion than the protrusion portion 144. Therefore, as shown in the present embodiment,
it is preferable to adopt the groove portion 143 as the rigidity change portion adjacent to the
outer periphery of the contact portion.
[0048]
The depth T1 and the width W1 of the groove portion 143 are not particularly limited. As shown
in FIG. 2, the deeper the depth T1 of the groove 143 with respect to the thickness T of the base
material 141, the thinner the thickness of the portion having the groove 143, the lower the
rigidity, and the easier it is to deform. In addition, as the width W1 is wider, the portion with low
rigidity is wider and it is easier to deform. Therefore, in order to make it easy to vibrate the
portion sandwiched by the groove portion 143, it is preferable that the depth T1 of the groove
portion 143 is deep and the width W1 is wide. However, on the other hand, it becomes difficult
to maintain the structure as the wall member 140. In addition, when the groove portion 143 is
integrally formed with the base material 141 by injection molding using a resin material, sink
marks easily occur. Therefore, the depth T1 and the width W1 of the groove portion 143 may be
appropriately set in consideration of the balance between the above-described point and the
unnecessary vibration reduction with the other rigidity change portions.
[0049]
In addition, as shown in FIG. 3, the effect of the groove part 143 of the structure which concerns
04-05-2019
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on this embodiment is confirmed by this inventor. In FIG. 3, the magnitude of the vibration at the
contact site at the time of transmission and reception is the vibration level 1 and the
configuration with the groove 143 (however, the protrusion has a configuration without the
groove 143 as a comparison object (no rigidity change)). 144 does not show the vibration level.
As shown in FIG. 3, by providing the groove portion 143, the vibration level of the contact
portion which is a portion sandwiched by the groove portion 143 is increased to about 1.3 times.
Further, the vibration level outside the groove 143 is reduced as compared to the configuration
without the groove 143. That is, the difference in vibration level between the contact portion and
the peripheral portion (portion outside the groove) is increased by providing the groove 143.
[0050]
The protrusion 144 may be formed when forming the base 141 forming the wall member 140 or
may be fixed to the base 141 after forming the base 141. It may be made of the same material as
the base material 141 or may be made of a different material. The protrusion 144 according to
the present embodiment is integrally formed of the same material as the base material 141. With
such a configuration, the manufacturing process can be simplified.
[0051]
As shown in FIG. 4, the protrusion height T2 and the width W2 of the protrusion 144 are not
particularly limited. Since the rigidity of the wall member 140 (base material 141) of the portion
where the protrusion 144 is provided is higher than at least the rigidity of the periphery of the
protrusion 144, the portion where the protrusion 144 is provided is higher than the other
portions. It is hard to deform. For example, as shown in FIG. 4, when the protrusion 144 is
provided so as to sandwich the portion of the base 141 including the contact portion with the
ultrasonic sensor 120, the protrusion 144 is provided at the time of transmission or reception of
ultrasonic waves. The portion becomes a rigid rigid restraint portion, and unnecessary vibration
is less likely to be transmitted to the outside (the side away from the contact portion) than the
projection 144 through the portion having the projection 144. Therefore, the energy of the
unnecessary vibration is reflected by the protrusion 144, and the portion of the base material
141 sandwiched by the protrusions 144 with the protrusion 144 as a node is easily vibrated (the
energy consumed for the vibration is To increase). As shown in FIG. 4, as the protrusion height
T2 of the protrusion 144 is higher than the thickness T of the base material 141, the rigidity of
the portion having the protrusion 144 is higher. Also, as the width W2 is wider, the portion with
high rigidity is wider, and it becomes difficult to deform. In order to enhance the effect of
restraint, it is preferable that the width W2 of the protrusion 144 be wide and the height T2 of
04-05-2019
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the protrusion be high.
[0052]
However, as the volume of the protrusion 144 is larger, there is a risk that a degree of sinking
may occur as seen from the outer surface 141 b of the wall member 140. On the other hand, in
the present embodiment, by configuring one large protrusion 144, the effect of the restraint is
not increased to reduce the unnecessary vibration, but a plurality of them are included in the
range where one large protrusion 144 is configured. By continuously providing the protrusions
144, the rigidity of one inferior protrusion 144 is increased. Further, each protrusion 144 is
configured to be elastically deformable in response to unnecessary vibration. That is, the
unnecessary vibration is reduced by the effect of the restraint and the effect of the elastic
deformation. Specifically, due to the effect of the restraint, the energy of the unnecessary
vibration transmitted to the contact portion from the protrusion 144 is reduced more than the
protrusion 144, and the vibration of the portion of the substrate 141 sandwiched by the
protrusions 144 is For example, as shown by an alternate long and short dash line in FIG. In
addition, the unnecessary vibration transmitted to the projection 144 reduces the energy of the
unnecessary vibration by the effect of the elastic deformation. By the above, unnecessary
vibration can be effectively reduced. Thus, the provision of the projection 144 can also narrow
the range (main transmission range of the ultrasonic wave (vibration) in the wall member 140) in
which the wall member 140 is easily vibrated (prescribed in a predetermined range). .
[0053]
The height T2 and the width W2 of the projection 144 are not particularly limited. By providing
the protrusions 144, it is possible to exert the effect of restraint not a little. Further, by
appropriately setting the constituent material and the projection height T2 and the width W2 of
the projection 144, the projection 144 can be configured to be elastically deformable. In the
elastically deformable configuration, it is preferable to resonate at a frequency λ of ultrasonic
waves (vibration) (where n · λ / 4 (n is a natural number) is a resonance length). With such a
configuration, the projection 144 is largely deformed in response to the unnecessary vibration,
and the unnecessary vibration can be effectively reduced. In the present embodiment, the
projection height T2 is set to a thickness equal to or greater than the thickness T of the base
material 141, and a resonance length (λ / 4 in the present embodiment) is secured. With such a
configuration, the resonance length can be easily secured, and unnecessary vibration can be
efficiently reduced. In addition, by making all the projection heights T2 of the plurality of
projections 144 equal, each projection 144 resonates with the unnecessary vibration of the
04-05-2019
19
predetermined frequency, and the unnecessary vibration is efficiently reduced. Further, the width
W2 is a thickness equal to or less than the thickness T of the base material 141. With such a
configuration, the rigidity of the protrusion 144 itself is reduced, and the protrusion 144 is easily
elastically deformed when the unnecessary vibration is transmitted. Also, the risk of sink marks
and / or the extent of sink marks can be reduced.
[0054]
In addition, the effect by elastic deformation of the projection part 144 shown to this
embodiment is clear also by the simulation by FEM (finite element method), as shown in FIG. As
shown in FIG. 5, when transmitting and receiving ultrasonic waves, the displacement maximum
vibration mode and the displacement minimum (maximum velocity) vibration mode are repeated,
but the projection 144 receives unnecessary vibration from the contact site. It is clear that it is
elastically deformed.
[0055]
Further, in the present embodiment, the protrusion 144 has four annular protrusions 144
provided on the continuous side so as to surround the contact portion and the groove 143 in the
direction away from the contact portion. Further, the width W2 of each protrusion 144 is fixed,
and the shape of each protrusion 144 is a shape along the outer periphery of the contact portion
(the ultrasonic wave transmission portion 142). Therefore, the unnecessary vibration transmitted
to the periphery of the contact area can be reliably reduced by the four projections 144. Further,
in combination with the effect of the ultrasonic wave transmission unit 142 and the effect of the
groove portion 143, desired directivity can be further easily ensured. In the configuration in
which the protrusion 144 is provided with the region including the contact region interposed
therebetween, the region between the protrusions 144 with the side (the rigidity change point)
on the inner side (contact region side) of the protrusion 144 as a boundary. It is preferable that
at least the planar shape of the inner side surface be a predetermined shape according to the
directivity. For example, even if the inner side surface is made the same plane rectangular shape
as the ultrasonic wave transmission part 142 and the outer side surface is made circular, the
effect according to the configuration shown in the present embodiment can be expected. In the
present embodiment, not only the inner side surface but also the outer side surface has a flat
rectangular shape (i.e., a fixed width). Further, the shape of the inner side surface (and the outer
side surface) of the protrusion 144 is substantially the same as the outer surface of the bottom
surface portion 122 of the ultrasonic sensor 120 in the planar direction of the wall member 140.
There is also an effect that it is easy to position the protrusion 144 (particularly, the innermost
04-05-2019
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one) as a mark when fixed to the
[0056]
The number of protrusions 144 is not limited to four. One or more than four may be used.
However, as described above, the feature of the protrusion 144 is that the range in which
vibration easily occurs is defined by the effect of the restraint or the effect of the restraint and
the effect of the elastic deformation. Therefore, when there are a plurality of them, at least the
restraining force is further increased, and the unnecessary vibration can be further reduced. If
the projection 144 is formed using a material having a damping coefficient larger than that of
the constituent material of the base 141 as a material different from that of the base 141, the
projection 144 is deformed to absorb vibrations and reduce unnecessary vibrations. be able to.
[0057]
In addition, as shown in FIG. 6, the effect of the projection part 144 shown to this embodiment is
confirmed by this inventor. In FIG. 6, the configuration without the protrusion 144 (same as the
groove in FIG. 3) is the comparison target, and the magnitude of the vibration at the contact
portion without the groove shown in FIG. The vibration level of a certain structure (the structure
of the present embodiment shown in FIG. 1 (b)) is shown. As shown in FIG. 6, by providing the
protrusion 144 together with the groove 143, the vibration level of the part in the separating
direction from the groove 143 is reduced compared to the structure of only the groove 143
(without the protrusion 144). In particular, the vibration level of the portion in the separating
direction from the protrusion 144 is reduced as compared with the structure of only the groove
143 (without the protrusion 144). That is, the difference in vibration level between the contact
portion and the peripheral portion is increased by providing the protrusion 144.
[0058]
As described above, according to the obstacle detection device 100 according to the present
embodiment, the ultrasonic sensor 120 is attached to the inner surface 141a of the wall member
140, and the transmission and / or reception of the ultrasonic wave is performed via the wall
member 140. It is configured to Therefore, since the ultrasonic sensor 120 can not be seen from
the outside of the wall member 140, the design can be improved.
04-05-2019
21
[0059]
In addition, the groove 143 and the protrusion as the rigidity changing portion are formed on the
inner surface 141a of the wall member 140 excluding the contact portion (the formation portion
of the ultrasonic wave transmission portion 142) of the ultrasonic sensor 120 (the outer surface
of the bottom portion 122a). By providing 144, the rigidity of the portion of the wall member
140 having the rigidity change portion is made different from that on the adjacent inner side
(contact portion side). Therefore, the unnecessary vibration transmitted from the contact portion
to the periphery thereof can be effectively reduced by the plurality of rigidity change portions.
Thus, when unnecessary vibration transmitted to the periphery of the contact site is reduced, for
example, at the time of transmission, the interference by the out-of-phase ultrasonic waves
transmitted from the periphery of the contact site is reduced. Further, in the configuration in
which the plurality of ultrasonic sensors 120 are arranged in parallel, the amount of transmission
of the unnecessary vibration to the adjacent ultrasonic sensors 120 is reduced. Therefore,
desired directivity can be secured.
[0060]
Further, in the planar direction of the wall member 140, the ultrasonic wave transmitting portion
142 is in the form of a rectangular plane longer in the vertical direction than in the horizontal
direction, and the groove 143 and the projection 144 are also in the same shape. Therefore, the
directivity of the obstacle detection device 100 is narrow in the vertical direction and wide in the
horizontal direction, and is suitable as an obstacle detection device for a vehicle.
[0061]
In the present embodiment, the groove portions 143 and the projection portions 144 having
different thicknesses with respect to the base material 141 are shown as the rigidity change
portions. However, if the rigidity is different from the adjacent inner site in the separating
direction with respect to the contact site, the unnecessary vibration can be reduced by any of the
effects described above. That is, in the obstacle detection device 100 according to the present
embodiment, not only the groove portion 143 and the protrusion portion 144 are rigidity
changing portions, but strictly speaking, a portion between the groove portion 143 and the
protrusion portion 144 and each protrusion portion 144 The portion between them is also a
rigidity change portion.
04-05-2019
22
[0062]
Further, in the present embodiment, an example in which the ultrasonic sensor 120 is adhesively
fixed to the wall member 140 has been shown. On the other hand, for example, as shown in FIG.
7, a portion of the protrusion 144 is used as a holder 145 for fixing the housing 122, and the
holder 145 and the housing 122 are fitted to each other to make the ultrasonic sensor 120 a
wall. It may be fixed to the member 140. FIG. 7 is a cross-sectional view showing a modified
example, and corresponds to FIG. 1 (b). Reference numeral 122 c shown in FIG. 7 is a fitting
projection provided on the outer peripheral side surface of the housing 122, and reference
numeral 145 a is a fitting groove provided in the holder 145. Adopting such a configuration can
improve the connection reliability of the ultrasonic sensor 120 with respect to the wall member
140 while reducing unnecessary vibration. In addition, you may use together adhesion fixation
and fitting fixation. Further, FIG. 7 shows an example in which the innermost (contact portion
side) protrusion 144 of the plurality of protrusions 144 is used as the holder 145. However, by
adjusting the projection height, the other projections 144 can be adopted as the holder 145. In
addition to fitting, a plate-like member is disposed at the tip of the protrusion of the protrusion
144, and the plate-like member and the tip of the protrusion and / or the housing 122 are fixed
by screwing or the like. The ultrasonic sensor 120 may be held between the wall member 140
and the wall member 140.
[0063]
Moreover, in this embodiment, all the rigidity change parts are cyclic | annular and showed the
example arrange | positioned concentrically centering on a contact site | part. However, it is not
limited to the ring. For example, as shown in FIG. 8, the ring may be divided by the slit-shaped
dividing portion 146. In addition, when providing the division part 146 in several rigidity change
parts, as shown in FIG. 8, it is good for the position of the division part 146 not to be in a straight
line with respect to a separation direction. With such a configuration, unnecessary vibration is
unlikely to escape to the outside. In FIG. 8, only the two protrusions 144 from the outside are
divided. In the case of an annular shape, the circumferential length becomes longer toward the
outer side, and it becomes difficult to elastically deform, so it is effective to have a structure
having the dividing portion 146. FIG. 8 is a plan view showing a modification, which corresponds
to FIG. 1 (a). In addition, a plurality of rigidity change portions may be scattered (distributed). By
providing the groove portion 143 (or the projection portion 144) so as to sandwich the contact
portion in the plane direction of the wall member 140 even if it is not annular, it is possible to
define the vibration-prone range of the wall member 140.
04-05-2019
23
[0064]
Further, in the present embodiment, an example is shown in which the groove portion 143 and
the protrusion portion 144 are provided as the rigidity change portion in order to reduce the
unnecessary vibration. However, only the groove portion 143 and the protrusion portion 144
may be configured. Further, as shown in FIG. 9, the inner surface 141a of the wall member 140
excluding the contact portion with the vibration portion (the outer surface of the bottom portion
122a) of the ultrasonic sensor 120 is made of a material having a larger attenuation coefficient
than the wall member 140. The members 160 may be stacked and arranged. According to this, it
is possible to absorb the energy of the unnecessary vibration by the damping member 160 and
to reduce the unnecessary vibration transmitted to the outer side (the separating direction with
respect to the contact portion) than the damping member 160. As the damping member 160, for
example, a rubber-like shape or the like can be employed. In addition, depending on the
laminated state of the damping member 160, a difference in rigidity of the wall member 140 is
generated with the peripheral portion of the laminated portion, so an effect by rigidity change
(for example, an effect by restraint as the projection 144) is expected. You can also. However, the
damping member 160 itself reduces unnecessary vibrations by absorbing unnecessary
vibrations. Therefore, even if the rigidity with the adjacent inner side is the same, unnecessary
vibration can be reduced. The arrangement of the damping member 160 is not particularly
limited. For example, it may be disposed in the groove 143. However, since the damping
coefficient is large and it is difficult to dispose in a narrow range, as shown in FIG. FIG. 9 is a
cross-sectional view showing a modification, which corresponds to FIG. 1 (b).
[0065]
Further, in the present embodiment, an example in which one ultrasonic wave transmission unit
142 is formed on the wall member 140 has been shown. However, a plurality of ultrasonic wave
transmission parts 142 may be formed on the wall member 140, and ultrasonic waves (vibration)
may be transmitted through the plurality of ultrasonic wave transmission parts 142.
[0066]
Second Embodiment Next, a second embodiment of the present invention will be described based
on FIG. FIG. 10 is a cross-sectional view showing a schematic configuration of the obstacle
04-05-2019
24
detection device 100 according to the present embodiment, and corresponds to FIG. 1 (b).
[0067]
The obstacle detection apparatus 100 according to the second embodiment has many parts in
common with those according to the first embodiment, and thus detailed description of common
parts will be omitted, and different parts will be mainly described.
[0068]
In the first embodiment, an example is shown in which the heights of all the protrusions in the
plurality of protrusions 144 are set equal.
On the other hand, the present embodiment is characterized in that the projection height of at
least one projection 144 is different from the projection height of the other projections 144.
[0069]
For example, when the physical property (for example, Young's modulus) of the wall member
140 changes due to temperature change as in the wall member 140 made of resin shown in the
present embodiment, even if the applied voltage to the ultrasonic transducer 121 is the same, it
vibrates due to temperature. The wavelength of (unnecessary vibration) will change. For example,
when the temperature is low, the Young's modulus is increased, the wall member 140 becomes
hard, and the wavelength of vibration (undesired vibration) becomes long. On the other hand, in
the present embodiment, as shown in FIG. 10, the projection heights of the four projections 144
provided continuously as in the first embodiment are different from each other. In other words,
the heights of the protrusions are set such that the resonance frequencies of the protrusions 144
are different from each other.
[0070]
As described above, according to the obstacle detection device 100 according to the present
embodiment, since the resonance frequencies of the plurality of protrusions 144 are shifted from
each other, even if the frequency of the unnecessary vibration changes due to the temperature
change, either Unwanted vibration can be reduced by the protrusion 144 of
04-05-2019
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[0071]
Moreover, such a configuration is not limited to the physical property change of the wall member
140 due to the temperature change, and for example, in the configuration that transmits and / or
receives a plurality of ultrasonic waves different in frequency, each unnecessary vibration is It
can be reduced efficiently.
[0072]
In FIG. 10, among the plurality of protrusions 144, the protrusion height of the innermost
(contact portion side) protrusion 144a is the highest.
In other words, the resonance length is increased for low temperature measures.
Adopting such a configuration makes it possible to efficiently reduce unwanted vibration at low
temperature, which is the most severe temperature condition, at a position close to the contact
site.
[0073]
Moreover, in FIG. 10, although the structure which protrusion height becomes low in order is
mentioned as it distances from a contact site | part, the order of protrusion height is not limited
to the said example.
[0074]
Third Embodiment Next, a third embodiment of the present invention will be described based on
FIG.
FIG. 11 is a view showing a schematic configuration of the obstacle detection device 100
according to the present embodiment, where (a) is a plan view seen from the inner surface side,
(b) is along the II-II line of (a) FIG. In FIG. 11A, for the sake of convenience, the outer peripheral
end of the outer surface of the bottom surface portion 122a of the housing 122 and the outer
peripheral end of the contact surface of the ultrasonic wave transmitting portion are illustrated
04-05-2019
26
by broken lines. Further, in FIG. 11B, the change point of the rigidity in the wall member 140 is
indicated by an alternate long and short dash line arrow only for one region with respect to the
contact portion with the ultrasonic sensor 120 for the sake of convenience.
[0075]
The obstacle detection apparatus 100 according to the third embodiment has many parts in
common with those according to the first embodiment, and thus detailed description of common
parts is omitted, and different parts will be mainly described.
[0076]
In the first embodiment, an example in which the main transmission range of the ultrasonic
waves (vibration) is narrowed (defined as a predetermined range) by providing the convex
ultrasonic wave transmission unit 142 in the wall member 140 is shown.
On the other hand, in the present embodiment, a convex ultrasonic wave transmission unit is
formed in the housing 122 constituting the ultrasonic wave sensor 120, and the main
transmission range of the ultrasonic wave (vibration) is determined by the ultrasonic wave
transmission unit. It is characterized in that the point is narrowed (defined in a predetermined
range). Therefore, the formation range of the ultrasonic wave transmission part according to the
present embodiment is limited within the facing surface to the wall member 140 of the housing
122 (that is, inevitably the contact surface of the housing 122 Although the area is smaller than
the contact surface and the entire contact surface of the ultrasonic wave transmission part is
included in the contact range with the contact surface of the housing 122, the ultrasonic wave
transmission part 142 of the wall member 140 It is similar.
[0077]
The basic configuration of the ultrasonic sensor 120 is the same as that shown in the first
embodiment. As shown in FIGS. 11 (a) and 11 (b), a convex ultrasonic wave transmission unit
128 (in the embodiment, an ultrasonic wave sensor 120 shown in the claims) is provided on the
outer surface of the bottom surface 122a of the housing 122. Vibration site is formed. Then, the
ultrasonic sensor 120 is fixed to the wall member 140 in a state where the ultrasonic wave
transmission unit 128 is in contact with the inner surface 141 a of the wall member 140. The
ultrasonic wave transmission unit 128 according to the present embodiment is also a columnar
04-05-2019
27
portion having a planar rectangular shape longer in the vertical direction than the horizontal
direction as the contact surface as the ultrasonic wave transmission unit 142 shown in the first
embodiment. , And the housing 122 are integrally formed using the same material.
[0078]
The basic configuration of the wall member 140 is also the same as that shown in the first
embodiment. As shown in FIGS. 11A and 11B, the formation site of the ultrasonic wave
transmission part 142 shown in the first embodiment and the formation site of the groove 143
provided adjacent to the periphery thereof are one groove 147. Has been replaced by. The
ultrasonic wave transmission unit 128 of the ultrasonic sensor 120 is adhesively fixed to the
bottom of the groove 147. The depth of the groove 147 is the same as that of the groove 143
shown in the first embodiment, and the ultrasonic wave transmission part 142 is replaced with
the ultrasonic wave transmission part 128.
[0079]
As described above, according to the obstacle detection device 100 according to the present
embodiment, the ultrasonic wave transmission unit 128 is provided on the outer surface of the
bottom surface portion 122 a of the housing 122 that constitutes the ultrasonic wave sensor
120. That is, the ultrasonic wave (vibration) is transmitted between the ultrasonic sensor 120
(the ultrasonic transducer 121 and the bottom 122a of the housing 122) and the wall member
140 through the ultrasonic wave transmitter 128. ing. Moreover, the ultrasonic wave
transmission part 128 is provided in a part of the outer surface of the bottom surface part 122a,
and the area in the surface direction differs at least from the bottom surface part 122a of the
housing 122 to which the ultrasonic transducer 121 is fixed. . Therefore, the main transmission
range of the ultrasonic waves (vibration) can be narrowed (defined as a predetermined range) by
the ultrasonic wave transmission unit 128. Further, as shown in the first embodiment, the rigidity
change portion can reduce unnecessary vibration. And a desired directivity is securable by these
effects.
[0080]
As shown in FIG. 11B, in the groove portion 147, since the contact portion with the ultrasonic
wave transmission portion 128 is a part of the bottom surface of the groove portion 147, the
04-05-2019
28
rigidity change point closest to the contact portion is the groove portion. It becomes the outer
surface of 147. However, the rigidity change portion closest to the contact portion is the portion
of the base material 141 between the groove portion 147 and the projection portion 144 (the
portion of the outer base material 141 adjacent to the groove portion 147). As the groove
portion 147 including the contact portion is easily vibrated, the effect of reducing the
unnecessary vibration is substantially the same as the structure (see FIG. 1) shown in the first
embodiment.
[0081]
In the present embodiment, the ultrasonic wave transmission unit 128 is integrally formed
(integrally molded) using the same material as the housing 122. Thus, based on the difference in
acoustic impedance, the reflection loss occurring at the interface of different materials can be
reduced. However, the ultrasonic wave transmission unit 128 may not be integrally formed with
the wall member 140, or may be configured using a material different from that of the wall
member 140.
[0082]
Further, in the present embodiment, the shape of the contact surface of the ultrasonic wave
transmission unit 128 in contact with the inner surface 141a of the wall member 140 is
configured to match the shape of the bottom surface portion 122a in the surface direction.
However, the shape can be arbitrarily set according to the area, the required detection area, and
the transmission / reception frequency of the ultrasonic wave.
[0083]
Further, in the present embodiment, an example in which one ultrasonic wave transmission unit
128 is formed for the housing 122 has been shown. However, a plurality of ultrasonic wave
transmission units 128 may be formed on the housing 122, and ultrasonic waves (vibrations)
may be transmitted through the plurality of ultrasonic wave transmission units 128.
[0084]
04-05-2019
29
Further, in the present embodiment, an example is shown in which the ultrasonic wave
transmission unit 128 of the ultrasonic sensor 120 is in contact with the bottom surface of the
groove 147. However, as shown in FIG. 12, as in the first embodiment, the annular groove 143 is
provided adjacent to the contact portion, and the base member 141 surrounded by the groove
143 (that is, the wall member 140 shown in the first embodiment). In the configuration, the
ultrasonic transmission unit 128 of the ultrasonic sensor 120 may be in contact with the
configuration without the convex ultrasonic transmission unit 142). Even with such a
configuration, the same effects as those described above can be expected. FIG. 12 is a crosssectional view showing a modified example, and corresponds to FIG.
[0085]
Also, the configuration shown in the present embodiment can be combined with the
configuration shown in the first embodiment (see FIGS. 7 to 9) or the configuration shown in the
second embodiment.
[0086]
Fourth Embodiment Next, a fourth embodiment of the present invention will be described based
on FIG.
FIG. 13 is a view showing a schematic configuration of the obstacle detection device 100
according to this embodiment, where (a) is a plan view seen from the inner surface side, (b) is
along the line III-III in (a). FIG. In FIG. 13A, for the sake of convenience, in the ultrasonic sensor
120, the outer peripheral end of the outer surface of the bottom surface portion 122a of the
housing 122 and the outer peripheral end of the contact surface of the ultrasonic wave
transmission unit are illustrated by broken lines. Moreover, in FIG.13 (b), the change point of the
rigidity in the wall member 140 is shown by the dashed-dotted-line arrow only for one area |
region with respect to the contact part with the ultrasonic sensor 120 for convenience.
[0087]
The obstacle detection apparatus 100 according to the fourth embodiment has many parts in
common with those according to the third embodiment, and thus detailed description of common
parts will be omitted, and different parts will be mainly described.
04-05-2019
30
[0088]
In the third embodiment, a convex ultrasonic wave transmission unit 128 is provided on the
outer surface of the bottom surface portion 122 a of the housing 122 constituting the ultrasonic
sensor 120 to narrow the main transmission range of ultrasonic waves (vibration) ( An example
of defining in a predetermined range is shown.
That is, as an ultrasonic wave transmission part, in narrowing the transmission range, an example
in which the shape element is strong is shown. On the other hand, in the present embodiment,
the wall member 140 and the ultrasonic vibrator 121 are in contact with a part of the bottom
surface portion 122a of the housing 122, and the acoustic impedance and the ultrasonic
vibration of the wall member 140 (base material 141) It is characterized in that an ultrasonic
wave transmission portion made of a material having an acoustic impedance intermediate to that
of the child 121 is provided. That is, an example is shown in which the material element is strong
in narrowing the transmission range as the ultrasonic wave transmission unit.
[0089]
Specifically, as shown in FIGS. 13A and 13B, an ultrasonic wave transmission unit formed of a
material (for example, resin) different from the other portion of the housing 122 at the center of
the bottom surface portion 122a. 129 are provided to be in contact with both the wall member
140 and the ultrasonic transducer 121. Here, the material different from the material of the
housing 122 is, for example, the case where the constituent material (resin) of the housing 122
and the constituent material (resin) of the ultrasonic wave transmission part 129 are different as
shown in this embodiment. For example, even if it is the same resin material, it is a concept also
including the case where glass cloth is contained in one side and is not contained in the other.
[0090]
The ultrasonic transmission unit 129 has an acoustic impedance substantially intermediate
between the acoustic impedance of the ultrasonic transducer 121 and the acoustic impedance of
the wall member 140, and the ultrasonic sensor 120 exhibits a desired directivity. The material,
shape, etc. are set.
[0091]
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31
The ultrasonic wave has a characteristic that the amount of reflection reflected without being
transmitted between the members increases as the change in the acoustic impedance between
members having different acoustic impedances increases.
As described above, the acoustic impedance of the ultrasonic wave transfer unit 129 is
approximately halfway between the acoustic impedance of the ultrasonic transducer 121 and the
acoustic impedance of the wall member 140. Therefore, the amount of ultrasonic reflection
between the ultrasonic transducer 121 and the ultrasonic transmitting portion 129, and further
between the ultrasonic transmitting portion 129 and the wall member 140 can be efficiently
reduced to increase the amount of ultrasonic transmission. it can.
[0092]
On the other hand, the housing 122 needs to satisfy the characteristics such as rigidity required
for fixing the ultrasonic transducer 121 or the like and attaching it to the wall member 140.
Therefore, it is very difficult to adopt an optimal material for transmitting the ultrasonic wave as
the material of the housing 122. As a result, the acoustic impedance of the bottom surface
portion 122 a made of the forming material of the casing 122 around the ultrasonic wave
transmission portion 129 deviates from the range between the acoustic impedance of the
ultrasonic transducer 121 and the acoustic impedance of the wall member 140. Even if it is
included between them, it becomes a value close to one of the acoustic impedances of the
ultrasonic transducer 121 and the wall member 140, and the difference with the other acoustic
impedance becomes large. For this reason, since the reflection amount of the ultrasonic wave is
increased compared to the ultrasonic transmission unit 129, the transmission amount of the
ultrasonic wave is lower than that of the ultrasonic transmission unit 129 at the bottom portion
122a made of the forming material of the housing 122. Do.
[0093]
Therefore, at the time of transmission and reception of the ultrasonic wave by the ultrasonic
transducer 121, the transmission of the ultrasonic wave in the bottom surface part 122a of the
housing 122 is mainly performed via the ultrasonic wave transmission part 129. As a result, the
main transmission range of the ultrasonic waves in the wall member 140 can be narrowed to the
range corresponding to the ultrasonic transmission part 129.
04-05-2019
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[0094]
Further, also in the present embodiment, as in the configuration shown in the third embodiment,
the rigidity change portion is provided on the inner surface 141 a except the contact portion of
the wall member 140. Specifically, as shown in FIGS. 13 (a) and 13 (b), a plurality of protrusions
144 are provided in the same manner as in the first embodiment, and grooves 143 and
ultrasonic wave transmission are provided inside the plurality of protrusions 144. The ultrasonic
sensor 120 is adhered and fixed to the flat portion of the base 141 where the portion 142 is not
provided, with the outer surface of the bottom portion 122 a of the housing 122 and the
ultrasonic transmission portion 129 as a contact surface. Therefore, unnecessary vibration can
be reduced by the effect of the restraint by the protrusion 144 and the effect of the elastic
deformation.
[0095]
As described above, according to the obstacle detection device 100 according to the present
embodiment, desired directivity can be secured by the effects of the ultrasonic wave transmission
unit 129 and the effects of the rigidity change unit.
[0096]
Also in this embodiment, as shown in FIG. 13A, in the plane direction of the wall member 140,
the contact surface of the ultrasonic wave transmitting portion 129 is a plane rectangle longer in
the vertical direction than the horizontal direction with respect to the ground. The rigidity
change portion is also formed in a planar shape corresponding to the outer peripheral end shape
of the ultrasonic wave transmission portion 129.
Therefore, it is suitable as an obstacle detection device for vehicles.
[0097]
In addition, a rigidity change part can be provided if it is an inner surface of the wall member
140 except a contact site | part with the vibration site | part (The ultrasonic transmission part
129 in this embodiment) of the ultrasonic sensor 120. For example, as shown in FIG. 14, a
04-05-2019
33
groove 143 may be provided adjacent to the outer periphery of the contact portion. With such a
configuration, due to the effect of the groove portion 143, it is possible to narrow the portion
that is likely to vibrate and to further reduce unnecessary vibration. Moreover, since the
peripheral part of the ultrasonic wave transmission part 129 of the bottom face part 122a does
not contact the wall member 140, the unnecessary vibration transmitted via the bottom face part
122a can be reduced. Therefore, desired directivity can be obtained. However, with such a
configuration, the bonding area between the ultrasonic sensor 120 and the wall member 140 is
smaller than the configuration shown in FIGS. 13 (a) and 13 (b), so the modified configuration of
the first embodiment (FIG. 7 and the corresponding description) are preferably adopted. FIG. 14
is a cross-sectional view showing a modified example, and corresponds to FIG.
[0098]
Further, in the present embodiment, an example is shown in which the ultrasonic wave
transmission unit 129 is flush with the outer surface of the bottom surface portion 122 a of the
housing 122. However, as shown in FIG. 15, a part of the ultrasonic wave transmission part 129
may be protruded from the outer surface of the bottom face part 122a, and only the ultrasonic
wave transmission part 129 may be in contact with the wall member 140. According to this,
since the peripheral part of the ultrasonic wave transmission part 129 of the bottom face part
122a does not contact the wall member 140, the unnecessary vibration transmitted through the
bottom face part 122a can be reduced. FIG. 15 is a cross-sectional view showing a modification,
which corresponds to FIG. 13 (b). In addition to the configuration shown in FIG. 15, as shown in
FIG. 14, a groove 143 may be provided adjacent to the outer periphery of the contact portion.
According to this, unnecessary vibration can be further reduced. However, even in the present
configuration, as in the configuration shown in FIG. 14, the bonding area between the ultrasonic
sensor 120 and the wall member 140 is smaller than the configuration shown in FIGS. 13 (a) and
13 (b). It is preferable to adopt a modified configuration of (Figure 7 and the corresponding
description).
[0099]
Also, the configuration shown in the present embodiment can be combined with the
configuration shown in the first embodiment (see FIGS. 7 to 9) or the configuration shown in the
second embodiment.
[0100]
The preferred embodiments of the present invention have been described above, but the present
invention is not limited to the above-described embodiments and can be variously modified and
04-05-2019
34
implemented without departing from the spirit of the present invention.
[0101]
The configuration of the rigidity change unit shown in the present embodiment is merely an
example.
It is possible to adopt any configuration in which a plurality of rigidity change portions are
provided on the inner surface 141a of the wall member 140 excluding the contact portion with
the vibration portion of the ultrasonic sensor 120 in the separating direction with respect to the
contact portion.
[0102]
In the present embodiment, as the ultrasonic sensor 120, a configuration example in which the
ultrasonic transducer 121 is accommodated in the housing 122 is shown.
However, for example, as shown in FIG. 16, the ultrasonic transducer 121 may not be
accommodated in the housing 122 and may be in contact with the wall member 140. Even in
such a configuration, the configuration shown in the first embodiment and the modified
configuration thereof and the configuration shown in the second embodiment can be applied. In
addition, in FIG. 16, the structure of 1st Embodiment (refer FIG. 1 (a), (b)) is shown. FIG. 16 is a
cross-sectional view showing another modified example, and corresponds to FIG. 1 (b).
[0103]
In the present embodiment, an example has been shown in which the outer peripheral shape of
the vibration portion of the ultrasonic sensor 120 and the planar shape of the rigidity change
portion match in the planar direction of the wall member 140. However, for example, as shown
in FIGS. 17A and 17B, the planar shape of the rigidity change portion may be different from the
outer peripheral shape of the vibration portion of the ultrasonic sensor 120. In FIGS. 17A and
17B, the outer surface of the bottom surface portion 122a of the housing 122 is flat and circular
as the vibration portion of the ultrasonic sensor 120, and the outer periphery of the contact
04-05-2019
35
portion in contact with the outer surface of the bottom surface portion 122a. The outer side
surface of the groove part 143 provided adjacently is made into the planar rectangular shape
longer in a perpendicular | vertical direction rather than a horizontal direction with respect to
the ground. Further, the projection 144 is also rectangular in plan view like the outer surface of
the groove 143. As described above, even if the wall member 140 and the ultrasonic sensor 120
do not have the ultrasonic wave transmission parts 142, 128, 129 for narrowing the
transmission range of the ultrasonic wave, the area easily vibrated only by the rigidity change
part. It is also possible to obtain the desired directivity by reducing unnecessary vibration while
defining. FIG. 17 is a view showing another modification, in which (a) is a plan view seen from
the inner surface side, and (b) is a cross-sectional view taken along the line IV-IV in (a). Although
FIG. 17 shows the ultrasonic sensor 120 having a configuration in which the ultrasonic
transducer 121 is accommodated in the housing 122, as shown in FIG. The same applies to the
ultrasonic sensor 120 which is not housed in the housing and is in direct contact with the wall
member 140.
[0104]
In the present embodiment, an example in which ultrasonic waves are transmitted and received
by one ultrasonic transducer 121 has been shown. However, it is also possible to adopt a
configuration in which the transducer for ultrasonic wave transmission and the transducer for
ultrasonic wave reception are divided.
[0105]
In the present embodiment, an example in which the circuit board 124 and the like are
accommodated in the case 122 together with the ultrasonic transducer 121 has been described.
However, the ultrasonic transducer 121 may be accommodated at least in the housing 122.
[0106]
In this embodiment, the wall member 140 is a bumper of a vehicle, and the obstacle detection
device 100 is configured as an obstacle detection device for a vehicle. However, as described
above, the vehicle body can be adopted as the wall member 140 other than the bumper, and a
member other than the vehicle constituent member can also be adopted.
04-05-2019
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[0107]
It is a figure which shows schematic structure of the obstacle detection apparatus which
concerns on 1st Embodiment, (a) is the top view seen from the inner surface side, (b) is sectional
drawing in alignment with the II line of (a). . It is a schematic diagram for demonstrating the
unnecessary vibration reduction by a groove part. It is a figure which shows the effect of a
groove part. It is a schematic diagram for demonstrating the unnecessary vibration reduction by
a projection part. It is a figure which shows a simulation result. It is a figure which shows the
effect of a projection part. It is sectional drawing which shows a modification. It is a top view
which shows a modification. It is sectional drawing which shows a modification. It is a sectional
view showing a schematic structure of an obstacle detection device concerning a 2nd
embodiment. It is a figure which shows schematic structure of the obstacle detection apparatus
which concerns on 3rd Embodiment, (a) is the top view seen from the inner surface side, (b) is
sectional drawing in alignment with the II-II line of (a). . It is sectional drawing which shows a
modification. It is a figure which shows schematic structure of the obstacle detection apparatus
which concerns on 4th Embodiment, (a) is the top view seen from the inner surface side, (b) is
sectional drawing in alignment with the III-III line of (a). . It is sectional drawing which shows a
modification. It is sectional drawing which shows a modification. It is a sectional view showing
other modifications. It is a figure which shows other modifications, (a) is the top view seen from
the inner surface side, (b) is sectional drawing in alignment with the IV-IV line of (a).
Explanation of sign
[0108]
100 · · · obstacle detection device 120 · · · ultrasonic sensor 121 · · · ultrasonic transducer 122 · · ·
housing 122a · · · (bottom of the housing portion 140) · · · · · · 141a wall member (Inside wall
member) Inner surface 142: Ultrasonic wave transmission portion 143: Groove portion (rigidity
change portion) 144: Protrusion portion (rigidity change portion)
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37
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