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JP2006153547

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DESCRIPTION JP2006153547
An axle bearing monitoring system for a railway vehicle by measuring an axle box sound capable
of accurately detecting an axle sound of an axle bearing of a railway vehicle, and a monitoring
method thereof. SOLUTION: In an axle bearing monitoring system for a railway vehicle by
measuring a shaft box sound, the microphones 4A are arranged on both sides of the rail, and the
microphones 4A are mounted offset to the shaft box side from the focal position of the parabolic
reflector 4B. , Axle box sound detection devices 4 and 5 that take in only the small box sound and
make the time for which the small box exists in the measurable section to be longer, and wheel
detection to obtain information from the wheel detection devices 11 to 14 And an analysis device
for analyzing output information from the wheel detection means. [Selected figure] Figure 1
Axle bearing monitoring system for railway vehicle by measuring shaft box sound and
monitoring method thereof
[0001]
The present invention relates to an axle shaft bearing monitoring system for a railway vehicle by
measuring a box sound and a monitoring method thereof.
[0002]
Heretofore, in order to detect damage generated in the axle bearings of a vehicle, it has been
necessary to attach an acceleration pickup to each axle box and travel on the premises, measure
vibration acceleration of all axle boxes, and analyze.
[0003]
03-05-2019
1
On the other hand, a parabolic reflector is disposed at a position facing the sound source with
respect to an observation target having a sound source, and a microphone array is disposed on
the focal plane of the parabolic reflector. A sound image visualization device for sound source
observation has been proposed in which the spatial distribution of sound pressure in front of a
reflector is continuously made into a two-dimensional image (see Patent Document 1 below).
[0004]
In addition, an abnormality monitoring system for a vehicle has also been implemented, in which
a microphone array (sound pressure sound field microphone array) (made by Brüel & Kj ー r) is
disposed along the railroad track and aside from the track to pass the vehicle.
JP-A-6-113387
[0005]
However, such a conventional axle bearing damage measurement method has a problem that it
requires a great deal of labor such as installation of a large number of microphones.
[0006]
An object of the present invention is to provide an axle bearing monitoring system for a railway
vehicle by measuring a shaft box sound capable of accurately detecting an axle sound of an axle
bearing of a railway vehicle in view of the above situation and a monitoring method thereof. .
[0007]
According to the present invention, in order to achieve the above object, [1] microphones are
disposed on both sides of the rail in the axle bearing monitoring system for railway vehicles
based on axial box sound measurement, and these microphones are selected from the focal
position of the parabolic reflector Axle box sound detection means which is mounted offset to the
side box side, takes in only the side box sound, and lengthens the time during which the side box
is in the measurable section, and obtains information from the wheel detection device The
apparatus is characterized by comprising a wheel detection means, and an analysis device for
analyzing output information from the axle box sound detection means and the wheel detection
means.
03-05-2019
2
[0008]
[2] In the axle shaft bearing monitoring method for railway vehicles by measuring the shaft box
sound, the microphones are attached to both sides of the rail offset to the shaft box side from the
focal position of the parabolic reflector, only the shaft box sound is captured, and The boxed box
sound is measured by extending the time during which the boxed box is present in the
measurable section.
[0009]
[3] In the axle shaft bearing monitoring method for a railway vehicle according to the above [2],
based on the shaft box sound output from the microphone, the output of the band pass filter
including the natural frequency of the shaft box impact sound in the band. The period of the
impulsive box impact sound is captured by obtaining a short-time RMS value by multiplying the
interval twice the period of the center frequency of the band pass filter by the Hanning window
function whose both ends are reduced.
[0010]
[4] The axle shaft bearing monitoring method for a railway vehicle according to the above [2] or
[3], characterized in that the track surface damage of the axle shaft bearing is analyzed based on
the shaft box noise.
[0011]
[5] The axle shaft bearing monitoring method for a railway vehicle according to the above [2] or
[3], characterized in that analysis of damage to the rolling surface of the rolling element is
performed based on the shaft box noise.
[0012]
According to the present invention, it is possible to mount a directional microphone in the
vicinity of the rail, monitor the sound generated from the axle box of the railway vehicle, and
automatically detect the damage generated in the axle bearing in the presence.
Therefore, the labor at the time of measurement can be reduced and daily monitoring can
contribute to the safe traveling of the railcar.
03-05-2019
3
Further, by having a function of accumulating the history of the measurement results for each
formation, it becomes possible to know the tendency of progression of damage, flat and the like,
and measurement accuracy can be improved.
[0013]
In the axle shaft bearing monitoring system for railway vehicles according to the present
invention, the microphones are disposed on both sides of the rail, and the microphones are
attached to the shaft box side offset from the focal position of the parabolic reflector, Shaft box
sound detection means for taking in only the car and making the time for which the shaft box
exists in the measurable section to be longer, wheel detection means for obtaining information
from a wheel detection device, and the box sound detection means And an analysis device for
analyzing output information from the wheel detection means.
Therefore, it is possible to accurately detect the axle noise of the axle bearing of the railway
vehicle.
[0014]
Hereinafter, embodiments of the present invention will be described in detail.
[0015]
FIG. 1 is a schematic view showing an arrangement of directional microphones of an axle bearing
monitoring system for a railway vehicle by measuring a shaft box sound according to an
embodiment of the present invention, and FIG. 1 (a) is a schematic plan view thereof; 2) is an
overall block diagram of an axle bearing monitoring system for a railway vehicle by measuring its
shaft box sound, and FIG. 3 is an output time of a directional microphone at the time of
measurement by this axle bearing monitoring system for a railway vehicle. FIG. 4 is a schematic
view showing the function of the directional microphone when the microphone according to the
present invention is placed at a position offset from the focal position, and FIG. 5 is a diagram
when the microphone is placed at the focal position as a reference example thereto. It is a
schematic diagram which shows the function of a microphone.
[0016]
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4
In FIG. 1, 1 is a rail, 2 is an axle of a railcar, 3 is a wheel of the railcar, and 4 and 5 are a box box
sound detection device.
While the microphones 4A and 5A are disposed on both sides of the rail 1, the microphones 4A
and 5A are mounted offset to the cabinet 1 from the focal positions of the parabolic reflectors 4B
and 5B. ing.
As a result, it is possible to capture only the axle box sound and to further extend the time during
which the axle box exists in the measurable section.
Note that, in FIG. 1, the distance a (5000 mm) indicates the distance between the wheels of the
adjacent vehicle, and the distance b (2500 mm) indicates the distance between the wheels in one
vehicle of the vehicle.
[0017]
In FIG. 2, reference numerals 6 and 7 are axial box sound amplifiers connected to the axial box
sound detection devices (directional microphones) 4 and 5, 8 are A / D converters connected to
the axial box sound amplifiers 6 and 9, 9. 11 is the wheel detection device for detecting the
position of the wheel (shaft box) 3 to be measured, the vehicle travel speed, and the vehicle travel
direction, and 14 to 18 are amplifiers connected to the wheel detection devices 11 to 14, 19 is
an interface (digital input device) connected to the amplifiers 15 to 18, 20 is information and
organization information 9 from the A / D converter 8 and the interface 19, and the box box
sound is input based on those information. An analysis device that performs analysis, and 21 and
22 are band pass filters connected between the box box sound amplifiers 6 and 7 and the A / D
converter 8.
The band pass filter may be configured as a digital filter in the analyzer.
[0018]
First, the axle bearing monitoring method of the present invention will be described.
[0019]
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5
[A] Preconditions of Measurement First, the axle box of a railway vehicle is attached to journals
at both ends of an axle, and is composed of an axle box, bearings, a lubricating device, an oil
drain, a front lid, and the like.
At the same time as holding a rotating axle, the bogie frame is supported via an upper shaft
spring.
[0020]
(1) When damage occurs to the bearing surface of the axle bearing (outer ring, inner ring), when
the rolling elements of the bearing pass through the damaged portion of the raceway, a cyclic
impact force is generated, and the shaft is oscillated. Sound of natural frequency is generated
from the box.
[0021]
(2) The number of impacts per wheel rotation due to raceway surface damage can be calculated
by the bearing type (outer ring diameter, inner ring diameter, rolling element diameter, number
of rolling elements, etc.), and 8 to 10 times per wheel rotation It is an extent.
[0022]
(3) Flats may occur on the wheel tread due to sliding during braking, etc., and the wheel tread
wears flat.
The occurrence of sliding at the time of braking is small, and when the flat is large, the flat
wheels are rare because the wheels are corrected, and even if there are flats, the number is about
one at one wheel.
When a flat occurs, a relatively large impact force is usually generated once per wheel rotation to
excite the axle box / rail.
Also, flats occur simultaneously on two wheels on either side of one axle.
03-05-2019
6
[0023]
(4) The flat generates relatively large impact force, so the sound generated from the axle box is
large.
[0024]
(5) During the measurement, in addition to the sound from the axle box, surrounding sounds
such as the sound of a vehicle-mounted device and the sound of another vehicle are also input to
the microphone.
In order to reduce the influence of the sound around them, directional microphones are used for
the microphones so that only the box sound of the measurement object is captured.
[0025]
(6) The directional characteristic of the directional microphone is narrow, so if the microphone is
placed at right angles to the rail, the measurement time becomes short and measurement is
impossible.
Therefore, a directional microphone is installed obliquely to the rail to lengthen the time during
which the axle box is in the measurable section.
[0026]
(7) The directional microphone uses a parabolic microphone or the like so as to focus on the axle
box.
Parabolic microphones are generally used to converge and amplify the sound from an infinite
distance source by placing the microphone 4A at the focal position of the parabolic reflector 4B
as shown in FIG.
03-05-2019
7
However, in the present invention, as shown in FIG. 4, the microphone 4A is placed on the sound
source side (axial box side) from the focal point of the parabolic reflector 4B so as to focus the
other box on the axial box position. Offset to the side) and install so that only shaft box sound is
captured.
[0027]
By this configuration, the other focal point becomes a focal area that is wide from the front to the
rear with respect to the parabolic reflector, and the amplification amount by the parabolic
reflector is also reduced. Thus, it is possible to capture only the target box sound of the
measurement target.
[0028]
[B] Measurement method (1) Input data recording (a) The entry of the formation into the
measurement section is detected by detecting the leading wheel of the formation by the wheel
detection device 11 or 14, and the measurement sequence is started.
Here, recording of the value after A / D conversion by A / D converter 8 of the shaft box sound
detected from shaft box sound detection devices 4 and 5 and the output of wheel detection
devices 11 to 14 is started.
[0029]
(B) When the measurement sequence is started by the wheel detection device 11, the number of
wheels that have passed the wheel detection device 14; conversely, when the measurement
sequence is started by the wheel detection device 14, the wheel that has passed the wheel
detection device 11 The number is counted, and the recording is ended when the number of
wheels for one formation is reached.
[0030]
(2) Analysis after data recording (a) The traveling direction of the vehicle is determined from the
wheel detection order of the wheel detection devices 11 and 14.
03-05-2019
8
[0031]
FIG. 3 shows the case where the vehicle passes from the wheel detection device 11 side, but in
FIG. 3, the time from the output start time of the wheel detection device 11 to the next output
end time of the wheel detection device 14 comes next It shall be a 1-axis measurement section
(1-axis measurement time).
In the case where the vehicle passes from the wheel detection device 14 side, although it is not
shown, a single axis measurement section (one axis measurement interval between the output
start time point of the wheel detection device 14 and the output end time of the wheel detection
device 11 coming next Measurement time).
[0032]
(B) The wheel detector 12 or 13 detects that the wheel has entered the judgment zone to
determine the judgment zone of the axle box to be measured, and from the traveling direction
obtained in (a) Determine the car number, the shaft position).
[0033]
In addition, as shown in FIG. 3, when a vehicle passes from the wheel detection apparatus 11
side, while a wheel passes the wheel detection apparatus 12 and passes the wheel detection
apparatus 13 (from the output start time of the wheel detection apparatus 12) Next, the output
end point of the wheel detection device 13) is determined as the determination section
(determination time) of the wheel to be measured.
In addition, when the vehicle passes from the wheel detection device 14 side, although it is not
illustrated, while the wheel passes the wheel detection device 13 and passes through the wheel
detection device 12, the determination section of the wheel to be measured (determination time)
Measure as.
[0034]
(C) From the time difference between the outputs of the wheel detection devices 11-14 and the
distance between the wheel detection devices 11-14, the traveling speed of the wheels during the
measurement section traveling is determined.
03-05-2019
9
[0035]
(D) From the position and running speed of the wheel in the judgment zone traveling and the
magnitude of the sound measured by the shaft box sound detecting device 4, 5, the sound caused
by the track surface damage is detected by the analysis method described later, and the track
surface damage Estimate the presence / absence of the bearing and determine the soundness /
requirement of the bearing raceway surface.
[0036]
(3) Post-analysis processing (a) Display the presence or absence of track surface damage (if
possible, the size of track surface damage) for each axle box and the judgment result of
soundness / relevant investigation.
[0037]
(B) Save the determination result and the input data as history data, and end the measurement
sequence.
[0038]
[C] Analysis Method FIG. 6 is a diagram showing the relationship between the waveform of the
impact sound in the determination section and a detailed time chart showing the embodiment of
the present invention, and FIG. 7 the relationship between the RMS value calculation section.
[0039]
The analysis method of track surface damage is described with reference to these figures.
[0040]
In FIG. 6, (a) is the output of the box box sound detecting device 4, 5 in the above determination
section, and (b) is the output of the box box sound amplifier 6, 7 after passing through the band
pass filters 21, 22. Output.
That is, by passing the output of the box box sound detecting device 4 or 5 through the band
pass filters 21 and 22 including the natural frequency of the box box sound in the band, the S / N
03-05-2019
10
ratio of the box box sound is improved. It becomes possible to catch the box impact sound
accurately.
[0041]
In addition, the shaft box impact noise caused by the damage generated on the bearing raceway
surface is a relatively small vibration of about 8 times to 10 times per wheel rotation as shown as
a precondition, and the wheel is a measurement section It can be observed about 10 to 16 times
before passing from the wheel detection device 11 to the wheel detection device 14.
[0042]
Therefore, track surface damage is detected by the following method.
[0043]
(A) In order to increase the S / N ratio for the measurement of the shaft box impact sound caused
by the track surface damage to be measured, the output from the shaft box sound amplifiers 6, 7
is set within the natural frequency of the shaft box impact sound within the band. Pass through
band pass filters 21 and 22 including.
[0044]
(B) About the output of the band pass filters 21 and 22 to which the outputs of the box box
sound amplifiers 6 and 7 are input while the wheels are traveling in the measurement section, 2
of the period of the center frequency of the band pass filters 21 and 22 A short-time RMS value
is sequentially determined by multiplying a doubled section by a Hanning window function or the
like in which both ends are reduced [see FIG. 6 (c), FIG. 7].
That is, as shown in FIG. 7, the output of the band pass filters 21 and 22 is multiplied by a period
twice the period of the center frequency of the band pass filters 21 and 22 by a Hanning window
function etc. By determining the value, it is possible to capture the cycle of the impact sound of
the axle box sharply.
This means that an RMS value [FIG. 6 (a)] obtained from the output of the box box sound detector
4, 5 and an RMS value [FIG. 6 (c)] obtained from the output of the band pass filters 21, 22. It is
clear by comparison.
03-05-2019
11
That is, it can be seen that the RMS value shown in FIG. 6C captures the impact sound of the axle
box more accurately and more precisely.
[0045]
(C) Frequency analysis such as FFT analysis is performed on the determined time series of the
short-time RMS values of the axle box sound detection devices 4 and 5 during traveling of the
measured section.
[0046]
(D) The frequency analysis result on the A side or B side (see Fig. 6) in the measurement section
corresponds to the shaft box impact sound interval (frequency) due to track surface damage that
can be calculated from traveling speed, wheel diameter, and bearing type If there is a peak, it is
checked whether the value of the peak exceeds the determination level.
If there is a peak and the peak value further exceeds the determination level, it is determined that
track surface damage has occurred.
[0047]
(E) Allowable fluctuation range of shaft box impact sound interval (frequency) due to track
surface damage that can be calculated from traveling speed and wheel diameter, bearing type,
when wheel diameter, bearing type can be known from inspection records, etc. Use the wheel
diameter to narrow the allowable variation range.
However, when the wheel diameter and bearing type are unknown, the wheel diameter is within
the upper limit and lower limit of the design value, and the fluctuation of the impact shock
interval between bearing types is the average impact of each bearing type. Increase the allowable
fluctuation range of the sound interval (frequency).
[0048]
03-05-2019
12
[D] Measurement history record Determination of track surface damage described above,
measurement information 9 (formation number, car number, axle position, wheel diameter for
each axle, bearing type for each axle, etc.) and actual measurement data Record as
By comparing with this data at the next and subsequent measurements, it is possible to know the
tendency of progression of the track surface damage and the fluctuation tendency of the shaft
box sound at the time of steady state, and it is expected to improve the measurement accuracy.
[0049]
[E] Detection of damage to rolling element The impact noise of the shaft box is usually generated
by damage to the bearing raceway surface, but is also generated by damage to the rolling surface
of the rolling element (damage to wheel tread surface) (flat mentioned above).
Also in this case, the detection is possible by obtaining the shaft box impact sound interval
(frequency) in the same manner.
In addition, the part which jumped out in above-mentioned FIG. 3 (FIG. 6, FIG. 7 is the same)
represents flat.
[0050]
Furthermore, the present invention is not limited to the above-described embodiments, and
various modifications are possible based on the spirit of the present invention, and these are not
excluded from the scope of the present invention.
[0051]
The axle shaft bearing monitoring system for railway vehicles by the shaft box noise
measurement of the present invention and the monitoring method thereof can be used as a tool
for axle shaft bearing monitoring of railway vehicles which can accurately detect the axle box
noise of the axle bearings of railway vehicles is there.
03-05-2019
13
[0052]
It is a schematic diagram which shows arrangement | positioning of the directional microphone
of the axle shaft bearing monitoring system for rail vehicles by shaft box sound measurement
which shows the Example of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the axle shaft bearing
monitoring system for rail vehicles by shaft box sound measurement which shows the Example of
this invention.
It is an output time chart of the directional microphone at the time of measurement in the axle
shaft bearing monitoring system for rail vehicles which shows the Example of this invention.
It is a schematic diagram which shows the function of a directional microphone at the time of
putting the microphone concerning this invention in the position offset from the focus position.
It is a schematic diagram which shows the function of the microphone at the time of putting the
microphone as a reference example in a focus position. It is a detailed time chart with the
waveform of the impulsive sound of the determination area which shows the Example of this
invention. It is a figure which shows the relationship of the RMS value calculation area which
shows the Example of this invention.
Explanation of sign
[0053]
1 Rail 2 Axle of Railroad Vehicle 3 Wheel of Railroad Vehicle 4, 5 Axle Box Sound Detection
Device (Directive Microphone) 4A, 5A Microphone 4B, 5B Parabola Type Reflector 6, 7 Axle Box
Sound Amplifier 8 A / D Converter 9 Organization information 11 to 14 Wheel detection device
15 to 18 Amplifier 19 Interface (digital input device) 20 Analysis device 21, 22 Band pass filter
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