JPH05157614A - Device and method for measuring vibration of gear - Google Patents

Abstract

PURPOSE:To accurately detect the vibration of a differential section without changing the vibrating state of the differential section at the time of measuring the vibration of the differential section by utilizing the resonance of a propeller shaft. CONSTITUTION:When a driving force is transmitted from a drive motor to a differential section 26 through a propeller shaft 28, the section 26 and shaft 28 resonate. The vibration of the shaft 28 is stronger than that of the section 26 and detected in a non-contact state by means of a vibration detector 34 using a laser beam. Since the detector 34 is moved in the lateral direction on a guide rail 32 by means of a motor 38, the detector 34 can detect the vibration of the shaft 26 at an arbitrary point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear vibration measuring apparatus and method for measuring vibration of a differential portion by utilizing resonance with a propeller shaft.

[0002]

BACKGROUND OF THE INVENTION As is well known, in vehicles,
The driving force of the engine is transmitted to the differential portion via the propeller shaft, and the driving force is further transmitted from the differential portion to the left and right wheels via the rear axle shaft.

Here, the differential part (simply,
"Differential" or "differential" may be referred to as "differential" or "differential"). The final gear (final reduction gear) and differential gear (differential gear) are housed in the carrier, and the driving force applied to the drive wheels in the vehicle. It has an important role in communication.

By the way, in each gear in the differential portion, if there is a variation in tooth shape or an assembly error due to an error in manufacturing the tooth surface, the meshing state between the gears becomes poor, and an abnormal vibration sound is generated. In some cases, it may cause a malfunction. Therefore, the inspection by the actual vibration measurement of the differential portion has been conventionally performed.

FIG. 14 shows a conventional gear vibration measuring device utilizing the resonance of a propeller shaft (for example, Japanese Patent Laid-Open Nos. 51-78375 and 2-389).
No. 30 publication).

In FIG. 14, the differential unit 1
One end of the propeller shaft 12 is connected to 0, and a drive motor 14 for vibration measurement is connected to the other end. Further, left and right wheels 18 are connected to the differential portion 10 via a rear axle shaft 16. Belts 2 are attached to the wheels 18 on the left and right of them.
The load generating motor 22 is connected via 0 or the like.

Further, a vibration detector 24 such as an acceleration pickup is joined to the carrier 10a forming the case of the differential portion 10, and the detection signal is sent to a vibration analysis device (not shown). An FFT, for example, is used as this vibration analysis device.

In the conventional gear vibration measuring apparatus configured as described above, the drive force generated by the drive motor 14 under the load applied by the motor 22 is transmitted to the differential portion 10 by the propeller shaft 12. ..

In this case, as shown in FIG. 15, the propeller shaft 12 as well as the vibration of the differential portion 10 are vibrated.
“Bending secondary vibration” occurs, and the propeller shaft 12 and the differential portion 10 resonate with each other under a specific condition F (indicated by 100 in FIG. 15). The wave number in the vibration of the propeller shaft 12 is not limited to the one shown in the figure, and varies depending on the conditions.

Due to this phenomenon, the differential unit 10
The vibration of is synergistically enhanced to some extent. Then, the vibration is detected by the vibration detector 24, and from the detection result, for example, tracking analysis as shown in FIG.
Alternatively, a fixed-order ratio analysis is performed, and the quality of the differential unit 10 is finally determined based on the peak level and the like. The vibration measurement is performed under various conditions while changing the rotation direction and changing the load amount and the rotation speed.

[0011]

However, the above-described conventional gear vibration measuring device and measuring method cannot detect vibrations with high sensitivity and cannot perform accurate vibration measurement. Therefore, the reliability of the inspection result of the differential portion is reduced.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a gear vibration measuring apparatus and a measuring method capable of accurately measuring the vibration of a differential portion.

[0013]

In order to achieve the above object, a gear vibration measuring device according to the present invention comprises a guide rail arranged in parallel with a propeller shaft at a constant interval.
And a vibration detector that is movably provided along the guide rail and that detects the vibration of the propeller shaft in a non-contact manner.

The gear vibration measuring method according to the present invention is
It is characterized in that vibration at one or a plurality of points in the propeller shaft vibrating together with the differential portion is detected.

[0015]

According to the gear vibration measuring apparatus of the present invention, the vibration detector for detecting the vibration in a non-contact manner can detect the vibration of the propeller shaft as it is without changing its vibration state (mode). Here, since the vibration detector is movable along the guide rail, it is possible to perform vibration measurement at an arbitrary position of the propeller shaft where secondary bending vibration occurs. In this case, the vibration of the differential unit itself is relatively small, but the vibration of the propeller shaft that resonates with the vibration has a large amplitude. Therefore, if the vibration at the peak position of that amplitude is measured, it will be detected more than before. With the sensitivity, you can grasp the vibration of the differential part indirectly.

Further, according to the gear vibration measuring method of the present invention, similarly to the above, the vibration of the propeller shaft in which the secondary bending vibration is generated can be measured to indirectly measure the vibration of the differential portion. In this case, by measuring multiple positions on the propeller shaft, a comprehensive analysis of vibration can be realized, which makes it possible to perform vibration determination in an abnormal mode that could not be found in the past, and by averaging each amplitude peak. The accuracy can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of the gear vibration measuring apparatus according to the present invention, and FIG. 1 is a diagram showing the overall construction of the first embodiment.

In FIG. 1, this device measures the vibration of the differential portion 26 by utilizing the resonance of a propeller shaft 28. A drive motor 30 for vibration measurement is connected to one end of the propeller shaft 28. The differential portion 26 is connected to the other end. The load motor and the like are not shown.

A guide rail 32 is arranged in parallel with the propeller shaft 28 at a constant interval, and a non-contact type vibration detector 34 is movably arranged along the guide rail 32. There is.

Here, the vibration detector 34 is composed of, for example, a non-contact laser Doppler vibrometer, and has a propeller shaft 28.
By irradiating a laser with respect to the propeller shaft 28, the reflected wave reflected by the propeller shaft 28 is received, and the frequency deviation due to the so-called Doppler effect is obtained to detect the vibration at a specific portion of the propeller shaft 28. In order to effectively reflect the laser light, the propeller shaft 28 is entirely coated with a paint that causes optical diffuse reflection.

In the present embodiment, the vibration is detected by using the laser, but in addition to this, the vibration of the propeller shaft 28 may be detected in a non-contact manner by using, for example, magnetism.

FIG. 2 shows a cross section taken along line II-II 'shown in FIG. 1. As shown in the drawing, the guide rail 32 is formed in a U-shaped cross section, and a conveying screw 36 is freely rotatable inside the guide rail 32. Has been inserted into. An E-shaped attachment 38 holding a vibration detector is connected to the carrying screw 36. Specifically, the carrying screw 36 is engaged with a through hole having a thread groove formed in the central convex portion of the fitting 38, and the fitting 38 is rotated by the forward and reverse rotations of the carrying screw 36.
At the same time, the vibration detector 34 moves left and right along the guide rail 32. Further, as shown in FIG.
A conveyance motor 38 is connected to one end of the one end so that the vibration detector 34 can be automatically moved. Of course, the vibration detector 34 may be moved manually.

In FIG. 1, a detection signal from the vibration detector 34 is input to the controller 40, while the controller 40 outputs a control signal to the drive motor 30 and the carry motor 38. Further, the controller 40 is connected to the FFT analyzer 42 and the display 44.

Although the distance between the propeller shaft 28 and the guide rail 32 is fixed in this embodiment, it may be variable according to environmental conditions.

An indirect vibration measurement of the differential portion 26 by the gear vibration measuring apparatus of this embodiment will be described with reference to FIG.

As shown in FIG. 3, in the resonance state of the differential portion 26 and the propeller shaft 28, the propeller is compared with the differential portion 26 as shown by an exaggerated broken line in FIG. The vibration on the shaft 28 is greater. That is, conventionally, vibration was detected by the pickup 46 at the position shown by A in the figure, but according to the gear vibration measuring device of the present embodiment, the vibration detector 34 is arranged at an appropriate position, The vibration of the propeller shaft 28 at the position where the amplitude peaks can be detected, and thus the vibration of the differential portion 28 can be indirectly measured with high sensitivity. In this case, as for the amplitude peak position, if the vibration mode is not known in advance, the vibration is sequentially detected from one end P ₁ to the other end of the propeller shaft 28, and the position where the maximum vibration level is obtained among the detection results. Certified by According to the vibration measurement as described above, as is clear from the comparison between the points A and B in FIG. 3, it is possible to obtain an amplitude amount about 30 times that of the conventional one, which results in a good S / N ratio. Vibration measurement can be realized.

Further, since the apparatus of this embodiment can perform vibration measurement in a non-contact manner, it has an advantage that it can perform vibration measurement irrespective of the shapes of the differential portion and the propeller shaft and can be applied to various types.

Next, the gear vibration measuring method according to the present invention using the gear vibration measuring device shown in FIG. 1 will be specifically described with reference to FIG.

In FIG. 4, in step 101, the process shown in FIG.
Drive motor 30 according to the instruction of the controller 40 shown in FIG.
Starts rotating. In step 102, it is determined whether or not the current rotation speed has risen to the rotation speed at which measurement is started, based on a detection signal from a rotation speed pickup (not shown).

When the rotation speed has risen to the predetermined value, the vibration detector 34 is conveyed to the initial value P ₁ in step 103. If the measurement position is set in advance, the vibration detector is transported to that position.

In step 104, the vibration detector 34 measures the vibration of the propeller shaft 28 in a non-contact manner.

Then, in step 105, step 1
The vibration measurement position in 04 and the measurement result are the controller 40
It is stored in a memory (not shown) provided in the. Specifically, the detection signal from the vibration detector 34 is once sent to the FFT analyzer 42, where it is subjected to frequency analysis, and then stored in the memory of the controller 40 in association with the vibration level for each frequency.

At step 106, it is judged if the vibration measurement is completed at all the measurement positions. In this example,
For example, 40 points are measured at equal intervals from one end to the other end of the propeller shaft 28.

Here, when the vibration measurement is not completed at all the measurement positions, the measurement position is changed in step 107, and the steps from step 104 are repeated. On the other hand, when the vibration measurement is completed at all the measurement positions, the following data analysis is performed in step 108. FIG. 5 is a flowchart showing the specific content of the data analysis in step 108 shown in FIG. Has been done. In step 201, 0 is assigned to the total level S, 0 is assigned to the maximum value MAX, and 1 is assigned to the measurement position P.

Here, the total level S indicates the total vibration level at each measurement position, and the maximum value MA
X indicates the maximum vibration level among the vibration levels at the respective measurement positions, and the measurement position P indicates the address on the guide rail. In step 202, the vibration level at point P is read from the memory built in the controller 40. For example, if point P is P ₁ in FIG. 3, the vibration level of the propeller shaft 28 corresponding to that point is read from the memory. Here, the vibration level is read out at a specific frequency or at a peak at that position.

At step 203, it is judged if the read vibration level Dp is larger than MAX.
If the vibration level Dp read in step 202 is higher than the vibration level previously assigned to MAX, MAX is rewritten in step 204, and conversely, if Dp is smaller than MAX, step 204 is executed. Be jumped

In step 205, the vibration level Dp is added, and the addition result is substituted for the total level S.

Then, in step 206, it is judged whether or not the above steps have been executed for all the measurement positions, and NO.
In this case, P is incremented by 1 in step 207, and the steps from step 202 described above are repeated. On the other hand, when the processing is completed for all the measurement positions, in step 208, S, MAX, D
Individual judgment is performed for each x. Here, Dx is a vibration level at an arbitrary position Px designated in advance. The individual determination is performed by determining whether or not the value of each item is between the upper limit and the lower limit set for each item.

For setting the upper limit of the vibration level Dx,
Determined by standards and experiments for each measurement point. For example,
The upper limit of D ₁ is 35 dB. On the other hand, D
As a general rule, the lower the vibration level, the more desirable the lower limit of x is to be set. Therefore, set a fixed value in consideration of the background and disconnection.

With respect to MAX and S, the upper limit and the lower limit are determined by the standards and experiments. Here, the determination by MAX is effective as data because when MAX is sufficiently larger than the standard value, a correlation is recognized with the case where the differential portion is actually arranged in the vehicle. However, in the vicinity of the standard value, there may be a case where the correlation with the actual state at the time of placement is not so good, so it is desirable to judge whether the vibration is good or bad based on the S value. That is, S is the sum of the vibration levels at each measurement point, and is advantageous in that it is less susceptible to noise and the like, and that the propeller shaft 28 and the differential portion 26 can be evaluated as a whole. As described above, in step 208, individual determination is made for each item.

Then, in step 209, a comprehensive judgment is made based on the judgment table shown in FIG. In FIG. 6, if all items are OK, the overall judgment is OK.
In all other cases, the overall judgment is NG.

In step 210, the individual judgment result and the comprehensive judgment result obtained in step 208 and step 209 are displayed on the display unit 44.

The vibration level Dx at an arbitrary Px is
It is the vibration level of a specific part of the propeller shaft 28,
For example, if Px is set in the vibration node, it may be possible to find a case where the vibration mode is different or the device itself is defective depending on the vibration level Dx. In addition, if it is known from experiments, etc. that a specific vibration occurs when there is a specific failure, by monitoring the vibration as Dx, the quality of the differential part can be judged by a simple measurement at only one point. Can be done. Furthermore, when the types of the differential unit 26, the propeller shaft 28, and the like are different, it is possible to deal with them by changing the upper and lower limits for each item in step 208. This makes it possible to change from the conventional uniform determination to a comprehensive determination that matches the measurement target. Incidentally, the number of measurement positions is predetermined depending on the measurement time, the vibration mode, the length of the propeller shaft 28, etc.
If the number is large, the measurement time will be short, but the measurement accuracy will be poor. On the other hand, if the measurement interval is shortened, the measurement time becomes longer, but the measurement accuracy can be improved.

In the rpm tracking analysis, the tracking measurement may be performed by automatically moving the vibration measuring instrument 34 to the vibration position where the amplitude is maximum. in this case,
Even if the vibration is slightly changed due to the difference in the machine of the differential unit, good vibration measurement can always be performed by controlling the vibration detector 34 to the left and right to automatically search the maximum amplitude.

Next, a second embodiment of the gear vibration measuring device according to the present invention will be described.

In the above-described first embodiment, the vibration of the differential portion 26 as a whole is evaluated even though the vibration of the differential portion 26 is caused by the meshing of gears for each tooth. Therefore, in the second embodiment, vibration analysis for each tooth is performed by a time division method which will be described in detail later.

FIG. 7 shows a second embodiment of the gear vibration measuring device, and FIG. 7 is an overall configuration diagram thereof. In addition,
The same components as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 7, the differential portion 26 is provided at one end of the propeller shaft 28 as in the first embodiment.
And an extension shaft 50 is connected to the other end thereof, and the driving force generated by the drive motor 30 is transmitted to the extension shaft 50 by a belt.

A guide rail 32 is arranged parallel to the propeller shaft 28, and a vibration detector 34 is movably arranged on the guide rail 32, and the vibration detector 34 is conveyed by a conveyance motor 38.

A load motor 54 is connected to the rear axle shaft 52, to which the rotational force is transmitted by the differential portion 26, via a belt or the like.

In the second embodiment, in order to detect the rotation speed of the propeller shaft 28, the extension shaft 50
A pickup 54 is arranged near the end of the
A pickup 56 is arranged near the end of the rear axle shaft 52 in order to detect the rotational speed of the rear axle shaft. Pickup 5 of them
The output signals of 4, 56 are sent to the controller 59 and the FFT analyzer 60.

In the second embodiment, in order to detect the rotation angle of the propeller shaft 28, the rotation angle detector 5
8 are provided. Specifically, the rotation angle detector 58 includes a detection unit 58a that optically detects rotation and an encoder 58b that outputs a rotation angle signal.
A display 62 is connected to the controller 59.

The principle of gear vibration measurement using the gear vibration measuring apparatus of the second embodiment configured as described above will be described in detail below.

First, the internal mechanism of the differential portion 26 will be described with reference to FIG. In FIG. 8, a drive gear (D / P) 64 is meshed with a ring gear (R / G) 66, and these gears form a final reduction gear. It should be noted that other mechanisms inside the carrier 26a that forms the housing of the differential portion 26 are not shown. Where D /
Set the number of teeth for P64 to 10 and the number of teeth for R / G66 to 4
Assuming that the gear ratio is 4.0, the gear ratio is 4.0, and the following description will proceed.

FIG. 9 shows an example of the vibration waveform detected by the vibration detector 34. The vibration waveform in FIG. 9 is obtained when the R / G 66 makes one revolution, that is, the D / P 64 makes four revolutions. Is. As shown in the figure, the vibration waveform is a set of waveform elements indicated by the tooth number section, and the meshing of the respective teeth is the main cause of the vibration.

With respect to the vibration waveform shown in FIG. 9, in the apparatus of the second embodiment, time division is introduced and frequency analysis is performed. Specifically, as shown in FIG. 10, the period of each section is set to T, and a period of 1 / 2T is added to both ends of each section to set the window W. That is, this window W has a period of 2T. A weighting function F such as a well-known Hamming function in FFT analysis is set for the window W, and the waveform extracted by the window W is weighted. Figure 10
In FIG. 3, the waveform extracted by the window W is shown as an extracted waveform 102.

Here, the reason why the window W of the period 2T is set for the section of the period T is to reduce the influence when the waveform A is cut out, and the data of the end portion in the tooth number section is made effective. This is for saving. From the above, it is understood that the windows W are set to overlap each other by half.

In the second embodiment, each extracted waveform 1 cut by the window W in this way is
02 is subjected to FFT analysis, and the result is output in a display format as shown in FIG. The display shown in FIG. 11 represents the vibration level distribution on the frequency for each tooth, and according to such a display, it is possible to clearly understand which tooth causes what kind of vibration. be able to. Therefore, vibration analysis can be performed for each tooth. Here, when the abnormal waveform is generated when the rotation angle of D / P is at a certain angle instead of the position of a specific tooth of R / G, D is not a defect of the tooth of R / G.
It is easy to understand that the / P tooth is defective. That is, it is possible to find defects in both R / G and D / P teeth.

A specific gear vibration measuring method to which the above-described principle is applied will be described with reference to FIG. 7 and with reference to FIGS.

In the above-described first embodiment, the vibration of the differential portion 26 as a whole is evaluated even though the vibration of the differential portion 26 is caused by the meshing of gears for each tooth. Therefore, in the first embodiment, the vibration diffraction for each tooth is performed by the time division method which will be described in detail later.

In FIG. 12, in step 301, the drive motor 30 is instructed by a command from the controller 59 shown in FIG.
Starts rotating. In step 302, based on the detection result of the pickup 54, the controller 59 determines whether or not the rotation speed has reached the measurement start rotational speed.

When the condition is satisfied, in step 303, the operator inputs the desired average number N of times.

In step 304, the rotation speed R (= gear ratio) of D / P per R / G rotation is calculated. This calculation of R is easily and automatically obtained from the detection results of the pickup 54 and the pickup 56, but may be input by the operator.

In step 305, measurement / analysis is executed. Details of the process of step 305 are shown in FIG.

In step 306, 0 is substituted for the count value i described later.

In step 307, the vibration detector 34
Vibration measurement is performed by. Then, in step 308, it is determined whether or not the current rotation speed is larger than R calculated in step 304. That is, in this step 308, one cycle shown in FIG. 9, that is, R
One rotation of / G is determined.

Here, when the vibration waveform for one cycle shown in FIG. 9 is fetched, step 309 is executed, and
The vibration waveform is divided by the window W shown in 0, and the extracted waveform 102 is obtained for each tooth.

In step 310, the FFT analyzer 6
0, frequency analysis is performed for each tooth, and the analysis result is stored in a memory (not shown) built in the controller 59 in step 311. Here, the vibration level at each frequency is stored for each tooth.

At step 312, it is judged if the count value i is larger than N set at step 303. That is, it is determined whether or not data has been captured up to the number of times of averaging. When i is smaller than N, i is incremented by 1 in step 313, and the above-mentioned step 3
Each step from 07 is repeated. If the condition is satisfied in step 312, step 314 shown in FIG. 12 is executed.

In FIG. 12, in step 314, the average value of the frequency analysis results stored in the memory is calculated. Then, in step 315, the average value is compared with a preset determination value, and if the average value exceeds the determination value, a defect is determined, and in step 316, the display 62 displays a defect, while If the average value is within the judgment value, a normal display is displayed on the display 62 in step 317. The comparison between the average value and the determination value in step 315 is performed for each frequency or for a specific frequency. In the display 62,
Normal or defective is displayed for each tooth.

As described above, according to the second embodiment,
In addition to the defect determination for the entire differential portion, the defect determination for each tooth can be performed, and more strict inspection of the differential portion can be realized. In this case, since the vibration is measured by detecting the secondary bending vibration of the propeller shaft 28, the vibration can be accurately measured, and since the vibration is detected in a non-contact manner, it is unnecessary for the vibration state. There is an advantage that an accurate vibration analysis can be performed without adversely affecting.

In each of the above embodiments, the vibration is detected by the non-contact type vibration detector, but it is also preferable to combine this with the conventional vibration detection by the pickup arranged on the carrier.

[0074]

As described above, according to the gear vibration measuring apparatus and the measuring method of the present invention, it is possible to indirectly and accurately detect the vibration of the differential portion and evaluate the highly reliable differential portion. Can be done. In this case, according to the present invention, since the vibration of the propeller shaft can be detected in a non-contact manner, there is an effect that accurate vibration measurement can be performed without changing the vibration state.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a gear vibration measuring device of a first embodiment.

FIG. 2 is a cross-sectional view showing a cross section viewed from a II-II ′ direction shown in FIG.

FIG. 3 is a flowchart showing vibration measurement by the gear vibration measuring device of the first embodiment.

FIG. 4 is an explanatory view conceptually showing a vibration state of a propeller shaft.

5 is a flowchart showing the specific processing contents of the data analysis shown in FIG.

6 is an explanatory diagram showing a determination table used in the comprehensive determination shown in FIG.

FIG. 7 is a diagram showing an overall configuration of a gear vibration measuring device of a second embodiment.

FIG. 8 is a perspective view showing a schematic internal configuration of a differential unit.

FIG. 9 is an explanatory diagram showing a vibration waveform when the ring gear makes one rotation.

FIG. 10 is an explanatory diagram showing windows set for each tooth and waveforms extracted by the windows.

FIG. 11 is an explanatory diagram showing a vibration frequency analysis result for each tooth.

FIG. 12 is a flowchart showing a vibration measuring method in the second embodiment.

FIG. 13 is a flowchart showing the specific content of the measurement / analysis process shown in FIG.

FIG. 14 is an explanatory diagram showing a configuration of a conventional gear vibration measuring device.

FIG. 15 is a conceptual diagram showing a state of secondary bending vibration of a propeller shaft.

FIG. 16 is an explanatory diagram showing an example of an analysis result in tracking analysis.

[Explanation of symbols]

 26 Differential part 28 Propeller shaft 30 Drive motor 32 Guide rail 34 Non-contact type vibration detector 38 Conveyor motor

Claims (2)

[Claims] 1. A gear vibration measuring device for measuring the vibration of a differential part in a state where a propeller shaft is connected to the differential part, wherein a guide rail is arranged in parallel to the propeller shaft at a constant interval, and A vibration detector provided movably along the guide rail, for detecting the vibration of the propeller shaft in a non-contact manner. 2. A gear vibration measuring method for measuring vibration of the differential part in a state where a propeller shaft is connected to the differential part, wherein vibration of one or more parts of the propeller shaft vibrating together with the differential part is detected. A method for measuring gear vibration, characterized in that vibration analysis of the differential portion is performed based on the detection result.