JPH0658849A - Vibration inspecting apparatus - Google Patents

Abstract

PURPOSE:To allow acquisition of machining information of each bearing component required for avoiding resonance between a bearing and other structure while specifying a vibration source bearing component. CONSTITUTION:Irregularities on the raceway surface of a bearing is detected through a speed type sensor 1 and an irregularity signal (speed amplitude) is subjected through an FFT analyzer 8 to frequency analysis thus obtaining a power spectrum. When a bearing component selecting section 13 selects bearing components, e.g. outer ring and inner ring, and a bearing feature setting section 14 set a feature data, e.g. number of rollers and rotational speed, an extraction angular number component determining section 15 determines an angular number component for exciting bearing vibration as an extraction angular number component based on vibration generating principle. A statistical quantity operating section then takes out a power spectrum corresponding to the extraction angular number component and operates a statistical quantity, e.g. root means square value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a roundness / shape of a bearing,
The present invention relates to a vibration inspection device suitable for evaluating waviness.

[0002]

2. Description of the Related Art Roundness of rolling parts (bearing parts) such as outer ring, inner ring and rolling elements (balls, rollers) that make up a rolling bearing
As a device for evaluating the shape and waviness, a roundness measuring device and a waviness meter are conventionally known.

A roundness measuring machine detects a shape signal indicating unevenness of a raceway surface of a rolling component by a tracing stylus, and a low-pass filter selects a predetermined angular range (number of undulations) from the detected shape signal. By extracting the corresponding frequency component, the change of the radius in the circumferential direction of the raceway surface of the bearing component, that is, the roundness is evaluated.

In the waviness meter, each bearing component is rotated by itself at a constant speed, and irregularities on the raceway surface are picked up by a speed type sensor, and the effective value of the speed amplitude or displacement amplitude within a certain angular range ( For example, as a root mean square value, usually two bands (Low Band, High Band)
The number of corners (number of undulations) is evaluated in d).

[0005]

By the way, in the finished bearing, not all the angular components of each bearing component excite vibrations, but only the specific angular component of each bearing component excites vibrations. The frequency corresponding to a particular angular component is also known. The vibration characteristics of the bearing are required to avoid resonance with a housing or the like in which the bearing is incorporated.

However, both the conventional roundness measuring machine and the waviness meter evaluate the total value of all the angular components within a constant angular range, and a specific value that excites bearing vibration or resonance is used. Since it is not possible to extract and evaluate only the angular component, to what extent the performance of each bearing component affects vibration and noise in the finished bearing, and which bearing component of the finished bearing is bad, that is, which bearing component Cannot determine whether the bearing causes the vibration of the bearing, and even if the resonance frequency with the housing in which the bearing is installed is given, the processing information of each bearing component for avoiding the resonance can be obtained. I couldn't get it.

The present invention has been made under such circumstances, and its purpose is to accurately grasp the level of the crest component of the undulation that causes the bearing vibration at the stage of a single bearing, and to complete the invention. Each bearing that can significantly reduce the vibration of the bearing, identify the bearing component that is the vibration source from the vibration of the completed bearing, and avoid resonance between the bearing and other structures An object of the present invention is to provide a vibration inspection device that can obtain processing information of parts.

[0008]

In order to achieve the above object, the present invention provides a sensor for detecting a vibration wave due to unevenness of a raceway surface by rotating a rolling component such as an outer ring, an inner ring and a rolling element by itself. In a vibration inspection device having frequency analysis means for frequency-analyzing the intensity of a vibration wave detected by the sensor, the intensity to be analyzed by the frequency degree analysis means is evaluated for any of displacement amplitude, velocity amplitude, and acceleration amplitude. Of the frequency to be extracted with respect to any one of the displacement amplitude, the velocity amplitude, and the acceleration amplitude subjected to the frequency analysis by the frequency analysis means based on the selection by the evaluation amount selection means and the evaluation amount selection means. A frequency range setting means for setting a range, a designating means for designating which rolling component, such as the outer ring, the inner ring, or the rolling element, is to be inspected for vibration, and designated by the designating means. The bearing vibration is excited based on the specification setting means for setting the specification data of the vibration inspection target, the vibration inspection target specified by the specifying means, and the specification data set by the specification setting means. Frequency component determining means for determining a frequency component to be used, and a statistical amount for calculating a statistical amount for the evaluation amount corresponding to the frequency component determined by the frequency component determining means or the frequency range set by the frequency range setting means. And calculation means.

[0009]

The sensor detects the vibration wave due to the unevenness of the raceway surface by rotating the rolling bearing constituted by the rolling parts composed of the outer ring, the inner ring and the rolling elements, or by rotating the rolling part alone.

The frequency analysis means frequency-analyzes the intensity of the vibration wave detected by the sensor.

The evaluation amount selecting means selects which of the displacement amplitude, the velocity amplitude and the acceleration amplitude is to be used as the analysis target of the frequency degree analyzing means.

The frequency range setting means sets a range of frequencies to be extracted for any one of displacement amplitude, velocity amplitude and acceleration amplitude subjected to frequency analysis by the frequency analysis means based on the selection by the evaluation amount selection means. .

The designation means designates which rolling component such as the outer ring, the inner ring, or the rolling element is the object of vibration inspection.

The specification setting means sets the specification data of the vibration inspection target designated by the designating means.

The frequency component determining means determines the frequency component that excites the bearing vibration based on the vibration inspection target designated by the designating means and the specification data set by the specification setting means.

The statistic calculating means calculates a statistic for the frequency component determined by the frequency component determining means or the evaluation amount corresponding to the frequency range set by the frequency range setting means.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an outline of a vibration inspection apparatus according to an embodiment of the present invention. A speed type vibration detection sensor 1, a rotary encoder 2, an amplifier 3, a low pass filter 4 and an A / D converter 5 are shown. , Synchronous adder 6, time axis waveform display control unit 7, FFT analyzer 8, evaluation amount selection unit 9, angular range setting unit 10, roundness / shape calculation unit 11, sensor scanning unit 12, bearing component selection unit 13 It has a bearing specification setting unit 14, an extraction angle number component determining unit 15, and a statistic calculating unit 16. The FFT analyzer 8 is
It has a T calculator 81 and a power spectrum calculator 82. Further, the time axis waveform display control unit 7, the evaluation amount selection unit 9, the angular range setting unit 10, the roundness / shape calculation unit 11,
The sensor scanning unit 12, the bearing component selection unit 13, the bearing specification setting unit 14, the extracted angular number component determination unit 15, and the statistic calculation unit 16 are configured by a personal computer PC.

The velocity type vibration detection sensor 1 is provided to detect the vibration velocity of the completed bearing or the rotation of the bearing component alone, and for example, a contact type moving coil type sensor is adopted. . To detect the vibration speed of the completed bearing, contact a stylus (not shown) with the outer circumference of the completed bearing to detect the vibration speed of the bearing component itself.
Detection is performed by touching the orbital surface with a stylus. The stylus of the velocity-type vibration detection sensor 1 is displaced due to a completed bearing as the workpiece W to be inspected, undulations of the raceway of the bearing component, etc., and at that time, a voltage signal of 1 V per displacement velocity of 1.778 m / sec. , I.e., generate a velocity amplitude signal. The rotation speed of the work W can be arbitrarily changed, but in the following description, it is assumed that the work W is rotated at a rotation speed of 480 rpm, that is, 8 rotations / sec.

The rotary encoder 2 is rotated in association with the rotation of the work W, and the rotary encoder 2 is rotated during one rotation of the work W.
Eight pulses are generated and the pulses are output to the A / D converter 5.

The velocity amplitude signal (voltage signal) detected by the velocity type vibration detection sensor 1 is amplified by the amplifier 3, the high frequency component of 7.5 KHz or more is reduced by the low pass filter 4, and the A / D converter 5 is obtained. Is output to. Therefore, the A / D converter 5 outputs the velocity amplitude signal per rotation to 2 based on the pulse from the rotary encoder 2.
Sampling is performed in the form of being divided into 048 sections, A / D conversion is performed, and a digital velocity amplitude signal is output to the synchronous adder 6 and the time axis waveform display control unit 7.

The synchronous adder 6 is set to 1 by the A / D converter 5.
Of the 2048 digital speed amplitude signals output per rotation, a predetermined number of speed amplitude signals corresponding to the same section are added to obtain a speed amplitude signal with a low S / N ratio, and the FFT calculation of the FFT analyzer 8 is performed. Output to the unit 81.

In the completed bearing, synchronous addition is not performed, and the velocity amplitude signal after A / D conversion can be directly output to the FFT calculation unit 81.

The time axis waveform display control section 7 displays the waveform of the velocity amplitude signal (time axis waveform) on a monitor.
When the work W has a flaw, the power spectrum obtained by the FFT analyzer 8 does not faithfully reflect the angular number (number of undulations), and therefore it is provided to find this flaw.

FFT operation unit 81 of FFT analyzer 8
Performs a calculation for converting a velocity amplitude signal (a signal on the time axis) output from the synchronous adder 6 into a signal on the frequency axis by a fast Fourier transform method. At this time, FF
The T calculator 81 takes in the velocity amplitude signal of 2048 points and performs a calculation to obtain a power spectrum (see FIG. 2).
reference). That is, the FFT analyzer 8 analyzes the frequency of the velocity amplitude signal corresponding to one rotation of the work W to obtain the power spectrum. In addition, the FFT analyzer 8
As will be described next, when the displacement amount or the acceleration amplitude is selected by the evaluation amount selection unit 9, the velocity amplitude spectrum is converted into the displacement amplitude spectrum or the acceleration amplitude spectrum. In addition, the power spectrum calculation unit 82
Can calculate up to 8192 Hz.

The evaluation amount selection unit 9 has a displacement amplitude, a velocity amplitude,
One of the evaluation quantities of the acceleration amplitude is selected according to the purpose. When the displacement amplitude is selected by the evaluation amount selection unit 9, the power spectrum calculation unit 82 integrates the velocity amplitude spectrum to convert it into a displacement amplitude spectrum, and when the acceleration amplitude is selected, differentiates the velocity amplitude spectrum. Then, the acceleration amplitude spectrum is converted.

The angular range setting unit 10 arbitrarily sets the angular range (frequency range) when the displacement amplitude is selected by the evaluation amount selection unit 9. In this case, the angle range is set by setting the upper limit and the lower limit.

For a single bearing component, the roundness / shape calculator 11 calculates the angular component (frequency component) within the range set by the angular range setting unit 10 by the power spectrum calculator 82. The roundness / shape is calculated based on the displacement amplitude spectrum. Roundness / shape calculator 11
The roundness / shape calculated by is displayed two-dimensionally on the display unit of the personal computer PC as shown in FIG. 3, for example. Note that FIG. 3 shows a case where the angle number range setting unit 10 sets an angle number range of 150 to 300 angles, and one scale of 12 scales indicates 0.2 nm.

The sensor scanning unit 12 scans the stylus of the velocity type vibration detection sensor 1 in order to shift the inspection position of the work W in the thrust direction. For example, the circularity of the outer ring raceway
In the case of inspecting the shape, as shown by the arrow in FIG. 4A, the stylus of the velocity type vibration detection sensor 1 is scanned at predetermined intervals in the thrust direction on the raceway surface of the outer ring. Sensor scanning unit 1
When the stylus of the velocity type vibration detection sensor 1 is scanned by 2, the velocity amplitude in the line corresponding to the scanning position is detected, the displacement amplitude spectrum is calculated by the FFT analyzer 8, and the roundness / shape calculation unit is calculated. The roundness / shape is calculated by 11. Then, the roundness / shapes in all the scanning lines are three-dimensionally displayed as shown in FIG. In addition, FIG. 4 is a diagram obtained by multiplying the measurement data obtained by measuring the roundness / shape of the outer ring raceway surface by 10,000 times,
The example in which the angle range setting unit 10 sets 2 to 50 angles as the angle range and the scanning pitch is 0.2 mm is shown.

Next, the bearing component selection unit 13, the bearing specification setting unit 14, the extracted angular component determination unit 15, and the statistic calculation unit 16 will be described. Before that, the relationship between the angular number and the frequency is explained. Will be explained.

The number of peaks (number of angles) of sine wave-like undulation that affects the radial, angular (tilt direction), and axial vibrations of the outer ring of the rolling bearing in which a constant thrust load is applied to rotate the inner ring, It is theoretically known that the relationship between the vibration of the outer ring and the vibration frequency is as shown in FIG. In Fig. 5, only the swell with a specific number of peaks (number of angles) causes the outer ring vibration, and the other number of peaks (number of angles)
It is shown that the swell with the swell does not cause the outer ring vibration. For example, when the number of rolling elements (Z) is 8, (nZ ± 1) in the radial direction of the inner ring, that is, 8
Only undulations having a number of peaks (angles) of ± 1, 16 ± 1, 24 ± 1 excite the radial vibration of the outer ring. In that case, the frequency of the outer ring is fi = fr ( Inner ring rotation speed) -f
c (Cage rotation speed: Revolution speed of rolling element)
(N8fi ± fr). The information in FIG. 5 is preset in a memory (not shown).

Bearing part selection section 13, bearing specification setting section 1
4, in the extraction angle number component determination unit 15 and the statistic calculation unit 16,
Using such a vibration generation principle, only the frequency component (number component) involved in the vibration generation is extracted from the power spectrum analyzed by the FFT analyzer 8.

The bearing component selection unit 13 includes the evaluation amount selection means 9
When either the velocity amplitude or the acceleration amplitude is selected by, the outer ring, the inner ring, or the rolling element is selected. In this case, when the work W as the detection target of the velocity-type vibration detection sensor 1 is a bearing component alone, that is, one of the outer ring, the inner ring, and the rolling element, the outer ring, the inner ring, or the detection target thereof, or When any one of the rolling elements is selected and the completed bearing is the detection target, the outer ring, the inner ring and the rolling element are sequentially selected one by one. Further, when the bearing ring (outer ring or inner ring) is selected, the bearing component selection unit 13 also selects the direction of swell (radial direction, angular direction, or axial direction).

For the completed bearing, the bearing specification setting unit 14
Is the number of rolling elements (Z), the inner ring rotational speed (fr), the cage rotational speed (rolling element) that are involved in the frequency of the outer ring vibration caused by the waviness of the raceway of the bearing component selected by the bearing component selection unit 13. Specifications data such as revolution speed: fc) and rolling element rotation speed (fb) are set according to the vibration generation principle of FIG. At this time, the bearing specification setting unit 14 also sets the highest order (value of n). For example, when the outer ring and the radial direction are selected by the bearing component selection unit 13, the radial frequency of the outer ring due to the waviness of the outer ring is nZfc in FIG. 5, so the bearing specification setting unit 14 Is the number of rolling elements (Z) and cage rotation speed (f
c), and set the highest order (n). Further, when the rolling element and the axial direction are selected by the bearing component selection unit 13, the axial frequency of the outer ring due to the waviness of the rolling element is 2 nfb in FIG. 5, so the bearing specifications are set. The section 14 uses the rolling element rotation speed (f
b), and set the highest order (n). If fi is included in the frequency equation in FIG. 5, fi =
(Fr: inner ring rotation speed)-(fc: cage rotation speed), and fi is inner ring rotation speed (fr) and cage rotation speed (f
Since it is determined by c), the bearing specification setting unit 14
Instead of inner ring rotation speed (fr) and cage rotation speed (f
c) is set.

The extracted angle number component determining unit 15 determines, based on the bearing component and the direction of the undulation selected by the bearing component selecting unit 13, the parameter data set by the bearing parameter setting unit 14, and the highest order. The corresponding frequency component (angle component) is determined according to the vibration generation principle of FIG.

The statistic calculation unit 16 cuts out a power spectrum corresponding to the extraction frequency determined by the extraction angle number component determination unit 15 from the velocity amplitude spectrum or the acceleration amplitude spectrum calculated by the power spectrum calculation unit 82. Statistics such as the square root of the root mean square value, the arithmetic mean value, and the maximum value are calculated and displayed on the display unit. For example, if Z = 6 and n = 3 for the outer ring alone, the five-sided, seven-sided, eleventh-sided, thirteenth-sided,
The 17th and 19th components are extracted. In this way, it is possible to judge the quality of each bearing component or completed bearing by cutting out only the power spectrum relating to the vibration of the outer ring and calculating the statistic.

Further, the statistic calculator 16 includes a velocity amplitude spectrum calculated by the power spectrum calculator 82,
Alternatively, from the acceleration amplitude spectrum, the angular range setting means 1
The power spectrum corresponding to the angular range (angular component) set by 0 is cut out, and statistical values such as the square root of the mean square value, the arithmetic mean value, and the maximum value are calculated and displayed on the display unit. The statistics in this case are used in the following cases.
That is, when the angular component (frequency component) that excites the resonance between the bearing and another structure is known in advance, the angular component is set by the angular range setting means 10. Then, the statistic calculator 16 cuts out the power spectrum corresponding to the angular component that excites the resonance, calculates the statistic such as the square root of the root mean square, the arithmetic mean, and the maximum value, and displays it on the display. To do. Therefore, based on the displayed content, it is determined whether or not resonance may occur between the bearing and other structures, and if resonance is likely to occur, each bearing is used to avoid it. It is possible to determine the processing conditions of the parts or change the number of rolling elements.

The present invention is not limited to the above-described embodiment. For example, the angle range setting means 10 sets each angle within the low-order angle range, and FIG. As shown, displacement amplitude spectrum, velocity amplitude spectrum,
It is also possible to perform a harmonic analysis for any of the acceleration amplitude spectra to obtain the magnitude of the component for each angle. Note that FIG. 6A shows an example of raw data when performing a harmonic analysis on the displacement amplitude per rotation of a steel ball (rolling element), and FIG. 6B shows FIG. 6A.
It is a graph of the raw data of.

In the conventional waviness meter, the frequency band to be evaluated is divided into 2 sections, but this is divided into 3 sections, 6 sections, ... Or 1 / N octave band, and the effective value and maximum of each section are divided. You may make it obtain a value etc.

Although the bearing or the bearing single component has been described, the present invention can be similarly applied to a gear, a pulley, or the like that causes periodic vibration.

[0041]

As described above, according to the vibration inspection apparatus of the present invention, the vibration of the completed bearing can be significantly reduced by grasping the degree of the angular component that causes the bearing vibration at the stage of bearing single product. In addition, it is possible to specify the bearing component that is the source of bearing vibration for the finished bearing.
In addition, it is possible to realize a vibration inspection device that can obtain processing information of each bearing component for avoiding resonance between the bearing and another structure.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a vibration inspection device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a velocity amplitude spectrum.

FIG. 3 is a diagram in which the measured roundness / shape is two-dimensionally displayed.

FIG. 4 is a diagram three-dimensionally displaying the measured roundness / shape.

FIG. 5 is a diagram showing a principle of bearing vibration generation.

FIG. 6 is a diagram showing an application example in which the vibration inspection device according to the embodiment of the present invention is applied to harmonic analysis.

[Explanation of symbols]

 1 Velocity type vibration detection sensor 2 Rotary encoder 4 Low pass filter 5 A / D converter 6 Synchronous adder 8 FFT analyzer 9 Evaluation amount selection unit 10 Angle number range setting unit 11 Roundness / shape calculation unit 12 Sensor scanning unit 13 Bearing Parts selection unit 14 Bearing specification setting unit 15 Extraction angle number component determination unit 16 Statistics calculation unit 81 FFT calculation unit 82 Power spectrum calculation unit PC Personal computer

Claims (1)

[Claims] 1. A sensor for detecting a vibration wave caused by unevenness of a raceway surface by rotating a rolling component such as an outer ring, an inner ring and a rolling element, and a frequency for frequency-analyzing the intensity of the vibration wave detected by the sensor. In a vibration inspection device having an analysis unit, an evaluation amount selection unit that selects which of displacement amplitude, velocity amplitude, and acceleration amplitude the evaluation amount of the analysis target of the frequency degree analysis unit is, and the evaluation amount. Frequency range setting means for setting a range of frequencies to be extracted for any one of displacement amplitude, velocity amplitude, and acceleration amplitude subjected to frequency analysis by the frequency analysis means based on the selection by the selection means; , An inner ring, a rolling element, etc., and a specification setting unit for setting the specification data for designating the vibration inspection target specified by the specification unit. A frequency component determining means for determining a frequency component for exciting bearing vibration based on the vibration inspection target designated by the designating means and the specification data set by the specification setting means; A vibration inspection apparatus comprising: a statistic calculating unit that calculates a statistic of the evaluation amount corresponding to the frequency component determined by the determining unit or the frequency range set by the frequency range setting unit.