JPH112239A - Device to measure various property of rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure various property by a single sensor during the use of a rolling bearing. SOLUTION: Vibration of a housing in which non-rotating outer rings 3 and 3 of ball bearings 1 and 1 being a rolling bearing securely fitted is picked up by a vibration pick up 7 being a single sensor. An output signal from the vibration pick up 7 is fed to a frequency converter 10 and further fed to an arithemetic unit 11. The various property, such as a rotation frequency, an axial load amount, a radial load amount, an axial rigidity value, a radial rigidity value, a contact angle, and a pre-load amount, of the ball bearings 1 and 1 are determined by the arithemetic unit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an apparatus for measuring various state values of a rolling bearing, which measures various state values relating to the rolling bearing when using the various rolling bearings. Used in conjunction with temperature measurements to predict the life of individual rolling bearings.

[0002]

2. Description of the Related Art Conventionally, rolling bearings such as ball bearings and roller bearings have been incorporated in the rotary support portions of various types of mechanical devices. Among these various rolling bearings, for example, a radial ball bearing is provided rotatably between an outer ring having an outer raceway on an inner peripheral surface, an inner race having an inner raceway on an outer peripheral surface, and the outer raceway and the inner raceway. And a plurality of balls. Then, based on the rolling of the ball, relative rotation between the member that internally supports the outer ring and the member that externally supports the inner ring can be freely rotated. When such a rolling bearing is used, as a device for measuring various state values related to the rolling bearing, for example, a rotation speed detection sensor or a temperature detection sensor is used to detect the rotation speed of the rolling bearing and the temperature near the bearing. There is a device. The rotational speed and the temperature in the vicinity of the bearing detected by such a device are used for controlling the operation of the rolling bearing and monitoring when an abnormality occurs in the rolling bearing.

On the other hand, when using a rolling bearing,
Its life needs to be predicted in advance. However, the life of a rolling bearing, that is, the time until failure (damage) occurs, is affected by various factors and is extremely large, so that the life of each rolling bearing is accurately predicted. It is extremely difficult to do. That is, because of the rolling bearing. Varies depending on the mounting error of each rolling bearing and the use condition. In addition, there are various factors that cause the failure, such as early flaking and seizure due to an excessive mounting error, heat and seizure due to improper preload, clearance and fitting, and abrasion and corrosion due to invasion of foreign matter and the like.

However, if the rolling bearing unexpectedly reaches the end of its service life, it not only causes damage to the members supported by the rolling bearing, but also seriously impairs the function of the entire machine incorporating the rolling bearing. There is a possibility. Because of this,
Predicting the life of individual rolling bearings is an important issue. In order to solve such a problem, as a method of estimating the life of each rolling bearing, a method of using a device for detecting the rotation speed of the rolling bearing and the temperature near the bearing as described above can be considered. However, only by detecting the rotational speed of the rolling bearing and the temperature near the bearing in this way, the operating condition of each rolling bearing cannot be sufficiently grasped, and the life thereof cannot be accurately predicted. That is, in order to accurately predict the life of each rolling bearing, not only detection of the rotation speed and the temperature in the vicinity of the bearing, but also an axial load, a radial load, a preload, a flaw analysis value applied to the rolling bearing, It is necessary to constantly observe various state values related to the rolling bearing such as the noise level while observing them over time. By observing the various state values of the rolling bearing over time, it is possible to more accurately predict the life of each rolling bearing and to analyze the causes when a failure occurs in the rolling bearing. become.

[0005] In order to constantly grasp the various state values when the rolling bearing is used, it is possible to provide a plurality of various sensors for each rolling bearing and measure the various state values of the rolling bearing. . However, if a large number of sensors are provided for each rolling bearing, not only does the production cost of the entire rolling bearing device increase, but also the weight of the entire rolling bearing device including the sensor can increase, Not preferred. The device for measuring various state values of the rolling bearing according to the present invention measures the various state values of the individual rolling bearings with a minimum number of sensors in view of the problems described above, thereby reducing the production cost of the entire rolling bearing device. The present invention has been made to make it possible to more accurately predict the life of the rolling bearing while minimizing an increase in weight.

[0006]

According to the present invention, there is provided an apparatus for measuring various state values of a rolling bearing, comprising: a first bearing ring-equivalent member having a first raceway surface on one side; Various states related to a rolling bearing including a second raceway-equivalent member having two raceway surfaces, and a plurality of rolling elements rotatably provided between the first raceway surface and the second raceway surface. An apparatus for measuring a value, comprising a vibration measuring element, a frequency converter, and a calculator. Among them, the vibration measuring element fixes one of the first and second raceway equivalent members, and the first and second raceway equivalent members correspond to the first and second raceway equivalent members. With the other member being rotated with respect to the member, the vibration of the one member is measured. Further, the frequency converter sends the output signal of the vibration measuring element and converts the frequency. The computing unit calculates the contact angle of the rolling bearing, the axial rigidity value, and the radial rigidity value by using the rotation frequency, the resonance frequency, the inner ring, the outer ring, and the rolling element component frequency, which are obtained by the frequency converter. , The axial load, the radial load, and the preload are obtained.

[0007]

According to the apparatus for measuring various state values of the rolling bearing of the present invention configured as described above, it is necessary to minimize the number of required sensors and to estimate the service life of each rolling bearing. Can be measured. That is, the vibration frequency of the rolling bearing, the axial load, the radial load, and the preload required for predicting the service life are measured only by measuring the vibration of one fixed member using a vibration measuring element as one sensor. Various state values such as quantity, axial rigidity value, radial rigidity value, contact angle, flaw analysis value, and noise value can be obtained. Then, using the various state values obtained in this manner and the temperature near the bearing obtained by the temperature detection sensor, these various state values and the temperature near the bearing are constantly grasped during use of the rolling bearing, and these values are obtained over time. Observable. Therefore, if a threshold value is set for each of these various state values and the temperature in the vicinity of the bearing, the life of each rolling bearing can be extended by examining when the threshold value is reached and the process leading to the threshold value. It can be predicted and the factors leading to its life can be known. Therefore, the apparatus for measuring various state values of the rolling bearing of the present invention more accurately predicts the life of an individual rolling bearing when it is used, while minimizing the production cost and weight increase of the entire rolling bearing apparatus. This prevents sudden failure of this rolling bearing,
Damage to the members supported by the rolling bearing can be prevented.

[0008]

1 and 2 show an embodiment of the present invention. FIG. 6 shows an angular type ball bearing 1 as an example of a rolling bearing to be measured according to the present invention. The ball bearing 1 has two or more bearings incorporated in a rotating support portion of various mechanical devices as one set. The outer ring 3 has an outer raceway 2 on an inner peripheral surface, and the inner race 5 has an inner raceway 4 on an outer peripheral surface. And a plurality of balls 6, which are a kind of rolling element, provided between the outer raceway 2 and the inner raceway 4 so as to roll freely. Based on the rolling of the balls 6, 6, relative rotation between a member such as a housing in which the outer ring 3 is internally fitted and supported and a member such as a shaft in which the inner ring 5 is externally fitted is supported. For example, in the case of the present example, the outer ring 3 is fixedly fitted in the housing, and the inner ring 5 is rotated. Such a ball bearing 1 has a straight line a connecting the rolling surface of each ball 6, 6 and the contact point between the outer ring raceway 2 and the inner ring raceway 4 so as to support not only the radial load but also the axial load. Is inclined by a predetermined angle (contact angle) α with respect to a straight line b connecting the centers of the balls 6, 6.
Each ball 6 between the outer raceway 2 and the inner raceway 4,
A so-called preload application is performed to press the pressure 6. However, the rolling bearing to which the present invention is applied does not necessarily need to be an angular type ball bearing, but may be another radial ball bearing such as a deep groove type or a thrust ball bearing.

In order to construct a device for measuring various state values of the rolling bearing of the present invention, as shown in FIG. The first outer ring 3 is internally fitted and fixed to the housing 12.
Then, relative rotation between the housing 12 and the shaft member 13 to which the inner rings 5 and 5 are externally fitted and fixed is made free. Further, a measuring element 8 of a vibration pickup 7 of a vibration measuring element, which is a kind of sensor, is brought into contact with one axial side surface of a housing 12 to which the outer rings 3 are fixed. The vibration pickup 7 measures the vibration of the outer ring 3 in the axial direction, and sends a signal representing the measured value to the amplifier 9. As the vibration measuring element, any one can be used as long as it can detect vibration in the axial direction, such as a displacement meter, a speedometer, and an accelerometer.

Next, the signal amplified by the amplifier 9 is extracted separately into a normal signal without conversion and a signal subjected to envelope processing. The normal signal is sent to a frequency converter 10 including a Fourier transformer. The frequency converter 10, a fast Fourier transform by using the (FFT = Fast Fourier Transform), the rotational frequency of the ball bearing 1 by the low-frequency components of the normal signal, i.e. obtaining the inner ring rotation frequency f _r. Incidentally, the inner ring rotation frequency f _r is regardless of the rotation state of the ball 6, 6, it can be determined from the vibration signal caused by the rotational speed of the inner ring 5. That is, the mounting error of the ball bearings 1 and 1,
Due to the ellipticity of the inner races 5, 5, vibration of a frequency proportional to the rotation speed of the inner race 5 is generated. Therefore, this vibration is caused by radial vibration, angular vibration,
It is measured as any of the axial vibrations, and from the low frequency component of the normal signal of this vibration, the inner ring rotation frequency f
You can know _r .

Further, the signal subjected to the envelope processing is
Like the normal signal, the signal is sent to the frequency converter 10.
Then, based on the envelope-processed signal, the frequency converter 10 uses the fast Fourier transform, and as shown in FIG. 4, the inner ring component frequency n · z caused by the vibration caused by the scratch on the inner ring 5 or the like. · f _i, the outer ring component frequency n · z · f _c caused by vibration based on scratches of the outer ring 3 and the like, ball 6,6
Ball component frequency 2n · f _b due to vibration based on scratches on the surface
(Where n is a natural number and z is the number of balls; the same applies hereinafter). FIG. 4 shows an example of a measurement result performed by the present inventor, based on a frequency analysis result of an envelope-processed signal, from an inner ring 5 caused by vibration of the inner ring 5, the outer ring 3, and the balls 6, 6, and the like. a diagram showing an outer ring, balls component frequency _{n · z · f i, n} · z · f c, the 2n · f _b. That is, the inner race 5 and the outer race 3 have slight scratches or the like on the inner raceway 4 and the outer raceway 2 formed on the outer peripheral surface or the inner peripheral surface. The inner ring 5 and the outer ring 3 vibrate in the radial, angular, and axial directions when the inner ring 5 rotates, based on the abutment between the scratches and the rolling surfaces of the balls 6, 6. The frequency of this vibration is proportional to the number z of balls. On the other hand, a small flaw or the like is also present on a raceway surface which is in contact with the inner raceway 4 and the outer raceway 2 at a part of the rolling surfaces of the balls 6, 6. Then, based on the scratches, the balls 6, 6 and the inner ring 5 and the outer ring 3 vibrate in the radial, angular, and axial directions when the balls 6, 6 rotate. However, such vibrations due to minute scratches or the like on the rolling surfaces of the balls 6, 6 tend to be large in the axial direction, and are accompanied by one rotation of the balls 6, 6, and the inner raceway 4 and the outer race Occurs twice each based on collision with orbit 2. Based on the wounds of the rolling surfaces of the balls 6, 6 in this manner, the inner ring 5, outer ring 3, the frequency balls 6,6 oscillates _{n · z · f i, n} · z · f c, 2n · f _b
Can be obtained by measuring any of radial vibration, angular vibration, and axial vibration of the outer ring 3 as a fixed member, and converting the vibration-enveloped signal into a frequency. Was determined in this manner, the inner ring 5 on the basis of the wound ball 6,6 etc., the outer ring 3, the frequency balls 6,6 oscillates _{n · z · f i, n} · z · f c, 2n · f b the respective feed to the calculator 11, 11, seeking inner ring rotation frequency f _i to the orbital revolution of the balls 6,6, ball revolution frequency f _c, the respective mean value of the ball rotation frequency f _b. Incidentally, the ball revolution frequency f _c is consistent with the rotational frequency of the retainer (not shown) for holding freely rotation and revolution of the ball 6,6.

[0012] Incidentally, the ball revolution frequency f _c is an inner ring rotation frequency f _i to the orbital revolution of the balls 6 and 6, can be obtained from the inner ring rotation frequency f _r. That is, these balls 6,
And the inner ring rotation frequency f _i for 6 revolution of said the inner ring rotation frequency f _r fed to the arithmetic unit 11, by pulling the inner ring rotation frequency f _i to the orbital revolution of the balls 6, 6 from the inner ring rotation frequency f _r (f _r -f _c), the ball revolution frequency f _c
Can be requested. However, the gist of the present invention, in order to predict the lifetime of the individual rolling bearing more precisely, lies in that measuring various state values for the rolling bearing, ball revolution frequency f _c as described above, the revolution of the balls 6 and 6 possible to find the inner ring rotation frequency f _i for is not the gist of the present invention.

[0013] Then, the average value of the inner ring was determined in the manner described above rotational frequency f _r and Ball rotation frequency f _b, as shown in FIG. 2, by feeding to the arithmetic unit 11, incorporated in the ball bearing 1 The contact angle α of each ball 6, 6 can be obtained. That is, the ball rotation number n _a is expressed as shown in the following equation (1). Note that D _pw
Is the ball pitch diameter, _Dw is the ball diameter, _ne is the outer ring rotation speed, _ni
Is the inner ring rotation speed. _{n a = {D pw / D} w -D w × (cosα) 2 / D pw)} × (n e -n i) / 2 --- (1) The outer ring 3 In this equation (1) Is non-rotated ( _ne =
0), the following equation (2) is derived. _{f b = {D pw / D} w -D w (cosα) 2 / D pw} (- f r / 2) --- (2) in the rolling element pitch diameter D _pw in the equation (2), rolling elements The diameter D _w is a dimension determined at the time of manufacture and is known. Therefore, the contact angle α may be calculated as a function of the inner ring rotation frequency f _r and Ball rotation frequency f _b. Therefore,
(2) the incorporated (with a processing function) The calculator 11, if Okurikome the average value of the inner ring rotation frequency f _r and Ball rotation frequency f _b, can be calculated the contact angle alpha.

Furthermore, the contact angle α calculated in this way, by feeding to the arithmetic unit 11, it is possible to determine the elastic deformation amount [delta] _n of the balls 6, 6. This will be described with reference to FIG. The 5, the ball bearing 1a is a deep groove ball bearing having an initial contact angle alpha _0, joined by axial load F _n, the inner ring 5a which constitutes the ball bearing 1a
There is shown a state in which displaced by [delta] _n in the axial direction. In this case, the groove radius center O _i of the inner ring 5a is also O _i '
In the axial direction displaced by [delta] _n, the contact angle is changed to alpha from alpha _0. As is apparent from FIG. 5, the distance a between the outer ring groove radius center _Oe and the initial inner ring groove radius center _Oi, and the distance b between the outer ring groove radius center _Oe and the displaced inner ring groove radius center O _i ′ are: , And are expressed by the following equations (3) and (4). Note that r _i
The groove radius, r _e of the inner ring 5a is a groove radius of the outer ring 3a. _{a = r i + r e -D} w --- (3) b = r i + r e + δ n -D w --- (4) Therefore, these (3), (4) a groove radius center of the inner ring 5a from the equation The following equation (5), which represents a radial distance c between O _i (O _i ′) and the groove radius center O _e of the outer ring 3a, is derived. _{(R i + r e -D w} ) cosα = (r i + r e + δ n -D w) cosα 0 - - (5) The (5) In the formula, the groove radius r _i of the inner ring 5a, the outer ring 3a and the groove radius r _e of the rolling element diameter D _w, initial contact angle α
_“0” is a dimension determined at the time of manufacture, and is known. Therefore, the elastic deformation amount [delta] _n is a function of the contact angle alpha. Such a relationship is not limited to the deep-groove type ball bearing 1a, but is realized by various radial type ball bearings such as the angular type ball bearing 1 shown in FIG. Thus, equation (5) to the arithmetic unit 11 incorporating, if Okurikome contact angle α determined in the manner described above, it can be obtained the elastic deformation amount [delta] _n.

Next, the amount of elastic deformation δ _n obtained in this manner
Is sent to the computing unit 11, the ball load Q applied to the balls 6, 6 can be obtained. That is, the ball load Q is expressed by the following equation (6). K _N is a constant determined by the material, dimensions and shape of the rolling elements. Q = K _N × δ _n ^3/2 (6) If the elastic deformation amount δ _n obtained as described above is sent to the arithmetic unit 11 incorporating the equation (6), the ball load amount is obtained. Q
Can be requested.

[0016] Then, by feeding the ball load amount Q calculated in this manner to the arithmetic unit 11, constitutes the axial load amount F _a of the ball bearing 1, the radial load amount F _r, the ball bearing 1 The contact rigidity value K of each ball 6, 6 can be obtained. That, and the axial load amount F _a, the radial load amount F _r, the following respective (7), represented by equation (8). _{F a = z × Q × sinα} --- (7) F r = z × Q × cosα --- (8) Therefore, the above ball load amount Q, the number of balls Z, and a contact angle alpha,
These (7), (8) if Okurikome formula above calculator 11 incorporating, can be calculated and the axial load amount F _a and radial load amount F _r.

On the other hand, the following equation (9) is derived from the above equation (6). dQ / dδ = 3/2 × K _N × δ _n ^1/2 (9) The differential dQ / dδ of the ball load Q by the elastic deformation shown in the equation (9) is a contact rigidity value. K (K = dQ /
dδ). Therefore, the (9) if Okurikome the elastic deformation amount [delta] _n type in the above arithmetic unit 11 incorporating, can be obtained the contact stiffness value K.

[0018] Incidentally, the contact stiffness value K, in addition to finding as described above, can also be determined by the resonant frequency f _n. That is, the resonance frequency f _n is expressed by the following equation (10). Here, k is a constant determined at the time of manufacturing. f _n = k × K ^1/2 (10) Accordingly, first, the resonance frequency f _n is obtained by frequency-converting the signal generated by the vibration of the outer ring 3 as the fixed member. Figure 3 is an example of measured results of performing the present inventors, the normal signal, is a diagram showing the resonant frequency f _n. If the resonance frequency f _n is sent to an arithmetic unit (not shown) incorporating the equation (10), the contact stiffness K can be obtained. Further, the axial stiffness Ka and the radial stiffness K _a The rigidity value _Kr can be obtained.

Further, as shown in FIG. 1, a signal obtained by extracting the vibration of the outer race 3, which is a fixed member, can be used for evaluating the noise level. That is, by extracting and comparing the maximum value of the signal level or the integrated value of an arbitrary frequency band, the transition of the noise level can be grasped, and the ball bearing 1 can be obtained.
Can be used to detect abnormalities.

The signal generated by the vibration of the outer ring 3, which is a fixed member, is converted into an envelope-processed signal, and the frequency-converted signal is present on the contact surfaces of the inner ring 5, the outer ring 3, and the balls 6, 6 as described above. Since the frequency of the vibration caused by the minute flaw or the like can be obtained, the flaw peak count can be further obtained using the signal generated by the vibration of the outer ring 3. The flaw peak count is generated as a flaw signal of the ball bearing 1 in proportion to the number of flaws existing on the rolling surfaces of the outer raceway 2, the inner raceway 4, and the balls 6, 6, and depends on the degree of the flaw. Different levels. Therefore, the number and degree of scratches on the ball bearing 1 can be determined as scratch analysis values.

As described above, the apparatus for measuring various state values of the rolling bearing according to the present invention uses the vibration measuring element, which is a single sensor, when the rolling bearing is used, and uses the vibration measuring element as a single sensor to measure the rotation frequency f _n , axial load amount F _a, radial load amount F _r, axial rigidity value K _a, the radial stiffness value K _r, contact angle alpha, wound analysis, noise level, can be further determine various status values of preload F. Therefore, it is possible to more accurately predict the life of the rolling bearing together with obtaining the temperature near the bearing of the rolling bearing by further providing a temperature sensor on the rolling bearing to be measured according to the present invention. That is, when the rolling bearing is used, the various state values and the temperature in the vicinity of the bearing can be constantly grasped, and the transition can be observed with time. Therefore, if a threshold value is set for each of these various state values and the temperature near the bearing, the life of each rolling bearing can be known by knowing when the threshold value is reached and the process leading to the threshold value. And the factors that lead to its lifetime can be known. Therefore, the apparatus for measuring various state values of the rolling bearing according to the present invention predicts the life of each rolling bearing more accurately at the time of use, while minimizing the increase in production cost and weight, and realizes the rolling bearing. By preventing a sudden failure, it is possible to prevent the member supported by the rolling bearing from being seriously damaged.

[0022] Incidentally, seeking contact angle α and the resonance frequency f _n bearing rigidity than K _a, further methods for determining the preload F, the applicant company issuing the "NSK Report" November 1989 issue of pages 59 to 66 Or by applying a well-known theory to the equations described on pages 248 to 252 of "Rolling Bearing Engineering", edited by the Rolling Bearing Engineering Editing Committee, published by Yokendo, etc. Therefore, detailed description is omitted.

[0023]

The apparatus for measuring various state values of a rolling bearing according to the present invention is constructed and operates as described above, so that the production cost and weight increase of the entire rolling bearing apparatus can be minimized while minimizing the increase. It is possible to more accurately predict the life of a rolling bearing when it is used, to prevent the rolling bearing from being suddenly damaged, and to effectively prevent serious damage to members supported by the rolling bearing.

[Brief description of the drawings]

FIG. 1 is a first half of a flowchart showing an example of an embodiment of the present invention.

FIG. 2 is the latter half.

FIG. 3 is a diagram showing a normal signal as an example of a measurement result performed by the inventor using an example of the embodiment of the present invention.

FIG. 4 is a diagram showing only a low-frequency portion of FIG. 3;

FIG. 5 is an exaggerated half sectional view showing a state in which an axial load is applied to the radial ball bearing.

FIG. 6 is a sectional view showing an example of a rolling bearing to be measured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Ball bearing 2 Outer ring track 3, 3a Outer ring 4 Inner ring track 5, 5a Inner ring 6 Ball 7 Vibration pick-up 8 Probe 9 Amplifier 10 Frequency converter 11 Computing unit 12 Housing 13 Shaft member

Claims (1)

[Claims] A first raceway-equivalent member having a first raceway surface on one side; a second raceway-equivalent member having a second raceway surface on a surface opposite to the one side; An apparatus for measuring various state values related to a rolling bearing composed of a plurality of rolling elements rotatably provided between a raceway surface and a second raceway surface, wherein the first raceway ring-equivalent member and the One of the two bearing ring-equivalent members is fixed, and the other of the first bearing ring-equivalent member and the second bearing ring-equivalent member is rotated while the one of the two members is rotated. A vibration measuring element that measures the vibration of the member, a frequency converter that sends the output signal of the vibration measuring element and converts the frequency, and a rotation frequency, a resonance frequency, an inner ring, an outer ring, and a rolling element component frequency obtained by the frequency converter. The contact angle of the rolling bearing and the An apparatus for measuring various state values of a rolling bearing including a computing unit for calculating all or a part of a axial rigidity value, a radial rigidity value, an axial load amount, a radial load amount, and a preload amount.