close

Вход

Забыли?

вход по аккаунту

?

JPH0946789

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH0946789
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the
technical field of a magnetic circuit constituting a speaker device.
[0002]
2. Description of the Related Art Conventionally, a speaker device has been proposed which is
provided with a magnetic circuit, a movable voice coil disposed in the magnetic gap of the
magnetic circuit, and a movable voice coil attached to the voice coil. ing. In this speaker device,
the electric signal supplied to the voice coil is converted into the sound generated by the
vibration of the diaphragm. Such a speaker device is referred to as a conductive speaker. In this
conductive type speaker device, the voice coil is supplied with an electric signal to move in the
magnetic flux in the magnetic gap portion along with the diaphragm to vibrate the diaphragm.
[0003]
In the magnetic circuit of this speaker device, a so-called external magnet type magnetic circuit
of a magnetic shield type has been proposed. As shown in FIG. 2, such a magnetic circuit has a
yoke 101 which is substantially disk-shaped of a magnetic material and to which an annular
drive magnet 103 is attached on the front surface. At the central portion of the front surface of
the yoke 101, a cylindrical center pole 102 is protruded coaxially with the drive magnet 103.
13-05-2019
1
Attached to the front surface of the drive magnet 103 is a top plate 106 formed of a magnetic
material and having a through hole at its central portion. The through hole of the top plate 106
and the tip end portion of the center pole 102 face each other to form a magnetic gap portion
107.
[0004]
An annular cancel magnet 104 is attached to the rear surface of the yoke 101. The cancel
magnet 104 has an opposite magnetic polarity to the drive magnet 103.
[0005]
In this magnetic circuit, the magnetic flux leakage from the drive magnet 103 is reduced by the
cancel magnet 104, and the magnetic flux density in the magnetic gap portion 107 is increased.
[0006]
This magnetic circuit constitutes a speaker device by attaching a frame 108 supporting the
diaphragm 111 to the front surface of the top plate 106.
The voice coil 114 is attached to the rear surface of the diaphragm 111 via a bobbin 113. The
voice coil 113 is located in the magnetic gap portion 107.
[0007]
In the diaphragm 111, the through hole at the central portion is closed by a cap portion 112.
Further, the diaphragm 111 is attached to the front end portion of the frame 108 by a gasket
109 via the peripheral edge side portion 110 via the peripheral edge side portion 110. The
bobbin 113 is supported by the frame 108 via a damper 117. The lead wire 115 from the voice
coil 114 is connected to a terminal portion 116 provided on the frame 108.
[0008]
13-05-2019
2
In addition, as a magnetic shield type magnetic circuit, as shown in FIG. 3, one in which a shield
cover 105 is attached to the rear surface portion of the cancel magnet 104 in the abovedescribed magnetic circuit has been proposed. The shield cover 105 is made of a magnetic
material and has a rear wall and a peripheral wall projecting forward from the peripheral portion
of the rear wall, and the front side is opened. The shield cover 105 has the front surface portion
of the rear wall portion attached to the rear surface portion of the cancel magnet 104, and the
front end portion of the peripheral wall portion is brought close to the peripheral portion of the
top plate 106. , Covers the yoke 101 and the cancel magnet 104.
[0009]
Also in this magnetic circuit, the magnetic flux leakage from the drive magnet 103 is reduced by
the cancel magnet 104, and the magnetic flux density in the magnetic gap portion 107 is
increased. In addition, in the magnetic circuit, by providing the shield cover 105, the present
invention can be applied to a speaker device in which the speaker box is miniaturized.
[0010]
As described above, also in the magnetic circuit having the shield cover 105 as described above,
the frame 108 supporting the diaphragm 111 is attached to the front surface portion of the top
plate 106 to configure the speaker device.
[0011]
By the way, in the magnetic circuit of the external magnet type and the magnetic shield type as
described above, the reduction of the leakage flux and the reliability of the shield are low, so that
the drive magnet 103 and the above-mentioned cancel It can not be said that the magnetic
energy of the magnet 104 is used sufficiently efficiently.
That is, the drive magnet can not be miniaturized while maintaining the magnetic flux density in
the magnetic gap portion.
[0012]
Therefore, in such a magnetic shield type magnetic circuit, it is difficult to achieve weight
13-05-2019
3
reduction and cost reduction.
[0013]
Therefore, the present invention is proposed in view of the above-mentioned circumstances, and
is an external magnet type and magnetic shield type magnetic circuit, in which the reduction of
the leakage flux and the shield are made reliable. An object of the present invention is to provide
a magnetic circuit in which the drive magnet and the cancel magnet are reduced in size while the
magnetic flux density in the magnetic gap portion is maintained while the magnetic energy of the
drive magnet and the cancel magnet is efficiently used. Try to solve the problem.
[0014]
[Means for Solving the Problems] In order to solve the above-mentioned problems, the magnetic
circuit according to the present invention is formed substantially in the shape of a flat plate from
a magnetic material, and integrally projects toward the front side at the center of the front
surface A yoke having a center pole, a ring-shaped drive magnet coaxially arranged on the front
face of the yoke with respect to the center pole, and an annular member made of a magnetic
material are provided on the front face of the magnet. A top plate coaxially arranged with respect
to the center pole and forming a magnetic gap with the center pole, and a cancel magnet
disposed on the rear surface of the yoke and having a reverse magnetic pole direction of the
drive magnet And a peripheral wall portion provided with a magnetic material and a rear wall
portion projecting forward from the peripheral portion of the rear wall portion, and the front side
is opened to form a front surface portion of the rear wall portion. The drive magnet, the yoke,
and a shield cover that covers the cancel magnet are configured by being attached to the rear
surface of the magnet and bringing the front end of the peripheral wall close to the peripheral
edge of the top plate. .
[0015]
Further, according to the present invention, the distance between the peripheral edge of the
cancel magnet and the peripheral wall of the shield cover is equal to or greater than the
thickness in the front-rear direction of the cancel magnet.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be
described below with reference to the drawings.
[0017]
13-05-2019
4
The magnetic circuit according to the present invention constitutes a speaker device by attaching
a frame 8 for supporting a diaphragm 11 as shown in FIG.
[0018]
This magnetic circuit has a disk-shaped yoke 1 formed of a magnetic material, and an annular
drive magnet 3 fixedly disposed (adhered) on the front surface of the yoke 1.
A cylindrical center pole 2 is integrally protruded at the center of the front surface portion of the
yoke 1.
The center pole 2 is coaxial with the drive magnet 3 and enters the central through hole of the
drive magnet 3.
[0019]
A disk-shaped top plate 6 having a through hole at the center portion of a magnetic material is
attached to the front surface portion of the drive magnet 3 (by adhesion).
The tip end portion of the center pole 2 is inserted into the through hole in the central portion of
the top plate 6.
The inner circumferential surface of the through hole at the center of the top plate 6 and the
outer circumferential surface of the tip of the center pole 2 face each other to form a magnetic
gap 7.
[0020]
An annular cancel magnet 4 is attached (by adhesion) to the rear surface of the yoke 1.
13-05-2019
5
The cancel magnet 4 is formed to have substantially the same size as the drive magnet 3 and has
a reverse magnetic pole direction with respect to the drive magnet 3.
That is, if the magnetic pole direction of the drive magnet 3 is, for example, N on the front side
and S on the rear side, the magnetic pole direction of the cancel magnet 4 is S on the front side
and N on the rear side. Then, a shield cover 5 is attached to the rear surface portion of the cancel
magnet 4 (by adhesion). The shield cover 5 is made of a magnetic material and has a rear wall
and a peripheral wall projecting forward from the peripheral portion of the rear wall, and the
front side is opened. The shield cover 5 has the front surface portion of the rear wall portion
attached to the rear surface portion of the cancel magnet 4, and the front end portion of the
peripheral wall portion made close to the peripheral portion of the top plate 6. The yoke 1 and
the cancel magnet 4 are covered.
[0021]
In this magnetic circuit, the distance t2 between the peripheral portion of the cancel magnet 4
indicated by the arrow t2 in FIG. 1 and the peripheral wall portion of the shield cover 5 is the
longitudinal direction of the cancel magnet 4 indicated by the arrow t1 in FIG. Thickness t1 or
more. That is, assuming that the inner diameter of the shield cover 5 is D and the diameter of the
cancel magnet 4 is d, then D> d + 2t1.
[0022]
The frame 8 constituting the speaker device is formed in a cylindrical shape whose front end side
is expanded in a substantially conical shape by a material having sufficient rigidity such as metal,
and the rear end side portion is the top plate 6 It is fixed to the front of the
[0023]
A peripheral portion of the diaphragm 11 is attached to the holding portion on the front end side
of the frame 8 by a gasket 9 via an edge portion 10.
The edge portion 10 is formed with flexibility and is displaceable in the front-rear direction.
13-05-2019
6
[0024]
The diaphragm 11 is composed of a substantially conical cone portion and a dome shaped cap
portion 12 attached to the cone portion in a state of closing the through hole at the central
portion of the cone portion. The peripheral portion of the cone portion 6 is continuously
provided to the edge portion 10.
[0025]
A bobbin 13 is attached to the central portion of the diaphragm 11 toward the rear side. The
bobbin 13 is formed in a cylindrical shape, and its front end is attached to the diaphragm 11. It is
desirable that the bobbin 13 be formed to be lightweight while having high rigidity. Therefore,
the bobbin 11 is formed by rolling a synthetic resin material such as a Bakelite board, paper or
cloth impregnated with an epoxy resin, a glass-epoxy board (glass fiber material solidified with
an epoxy resin), metal foil, paper into a cylindrical shape. It is desirable to form.
[0026]
The voice coil 14 is adhered to the outer peripheral surface of the rear end side of the bobbin 13.
The voice coil 14 has a lead wire (typhoid wire) 15, and is wound and formed in a cylindrical
shape. The lead wire 15 is soldered and connected to the contact portion 16 provided on the
frame 8.
[0027]
The voice coil 14 is located in the magnetic gap portion 7. That is, the voice coil 14 is coaxial
with the center pole 2 and enters between the center pole 2 and the inner surface of the through
hole at the center of the top plate 6.
[0028]
The front end side portion of the bobbin 13 is connected to and supported by the rear end side
portion of the frame 8 via a flexible and vibration absorbing damper 17.
13-05-2019
7
[0029]
As described above, in the magnetic circuit constituting the speaker device, the magnetic flux
leakage from the drive magnet 3 is reduced by the cancel magnet 4 and the magnetic flux
density in the magnetic gap portion 7 is increased.
Further, in this magnetic circuit, the above-described shield cover 5 can be applied to a speaker
device in which the speaker box is miniaturized.
[0030]
EXAMPLES Specific examples of the present invention will be given below.
[0031]
As shown in the above [Table 1], the magnetic circuit according to the present invention and the
magnetic circuit according to the present invention are formed by the conventional external
magnet type and magnetic shield type magnetic circuit shown in FIG. The magnetic flux density
at 107, 7 was measured.
[0032]
The top plates 106 and 6 and the shield covers 105 and 5 have the same shape, and their
volume ratio is 1: 1.
[0033]
The drive magnet 103, 3 has an outer diameter (φ) of 60 mm, an inner diameter (φ) of 26 mm,
and a thickness (t) of 10 mm according to the present invention. The inner diameter (φ) is 22
mm, the thickness (t) is 6 mm, and the volume ratio of these is 2.4: 1.
[0034]
The conventional cancel magnet 104, 4 has an outer diameter (φ) of 50 mm, an inner diameter
(φ) of 22 mm, and a thickness (t) of 7 mm, whereas the present invention relates to an outer
diameter (φ) of 45 mm. The inner diameter (φ) is 22 mm, the thickness (t) is 5 mm, and the
volume ratio of these is 1.8: 1.
13-05-2019
8
[0035]
The yokes 101 and 1 of the prior art have an outer diameter of 55 mm and a height of 15 mm
for the center pole 102, whereas in the present invention, the outer diameter is 45 mm and the
height of the center pole 2 is 11 mm. And their volume ratio is 1.5: 1.
[0036]
As described above, in the magnetic circuit according to the present invention, the volumes of the
drive magnet 3, the cancel magnet 4 and the yoke 1 are made smaller than those in the
conventional magnetic circuit. And it is lightweight.
[0037]
The width of the magnetic gap portions 107 and 7 is 0.87 mm in the case of the present
invention, compared to 0.85 mm in the conventional case.
[0038]
The magnetic flux density in the magnetic gap portions 107 and 7 is 11300 gauss in the
conventional case, whereas it is 11200 gauss in the invention according to the present invention,
and is hardly changed.
[0039]
As described above, in the magnetic circuit according to the present invention, the distance
between the peripheral edge of the cancel magnet attached to the back surface of the yoke and
the peripheral wall of the shield cover covering the yoke and the cancel magnet Is set to be equal
to or greater than the thickness in the front-rear direction of the cancel magnet.
Therefore, in the magnetic circuit, the reduction of the leakage flux and the shielding are
ensured, and the magnetic energy of the drive magnet and the cancel magnet is efficiently used.
[0040]
That is, the present invention is an external magnet type and magnetic shield type magnetic
circuit, and while the magnetic flux density in the magnetic gap portion is maintained, the drive
magnet and the cancel magnet can be miniaturized and the weight can be reduced. Can provide a
13-05-2019
9
magnetic circuit.
[0041]
Brief description of the drawings
[0042]
1 is a longitudinal sectional view showing the configuration of a speaker apparatus having a
magnetic circuit according to the present invention.
[0043]
2 is a longitudinal sectional view showing the configuration of a speaker apparatus having a
conventional magnetic circuit.
[0044]
3 is a longitudinal sectional view showing the configuration of a speaker apparatus having a
conventional magnetic circuit provided with a shield case.
[0045]
Explanation of sign
[0046]
1 yoke 2 center pole 3 drive magnet 4 cancel magnet 5 shield cover 6 top plate 7 magnetic gap
portion
13-05-2019
10
Документ
Категория
Без категории
Просмотров
0
Размер файла
18 Кб
Теги
jph0946789
1/--страниц
Пожаловаться на содержимое документа