JPH11153425A - Method and device for measuring bearing clearance of radial ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure the bearing clearance extending in the radial direction of a radial ball bearing by detecting the vibration of an inner ring or an outer ring in the excited state of the radial ball bearing having a plurality of balls arranged between an inner ring raceway and an outer ring raceway, to which balls a prescribed pre-load is imparted, and performing an operation. SOLUTION: A radial ball bearing 1 has a plurality of balls 6 arranged between an inner ring raceway 3 provided on the circumferential surface of an inner ring 2 and an outer ring raceway 5 provided on the inside surface of an outer ring 4, and a prescribed pre-load is imparted to the balls 6 by a load based on the weight of the outer ring 4. The vibration of the outer ring 4 is detected by a vibration detector 11 while exciting the ball bearing 1 by a shaker 10, whereby the resonance frequency fn of the ball bearing 1 is determined. Since the axial rigidity Ka, resonance frequency Fn and floacting mass (m) of the ball bearing 1 have the relation of fn=(Ka/m)<1/2> /2π, the radial bearing clearance can be easily and quickly provided on the basis of the resonance frequency fn detected by the vibration detector 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a bearing clearance of a radial ball bearing, which measure the bearing clearance in a radial direction of a radial ball bearing incorporated in various precision rotating parts such as a rotary support portion of precision equipment. Use for quick and accurate measurement.

[0002]

2. Description of the Related Art Radial ball bearings, in which a plurality of balls are arranged between an inner raceway provided on an outer peripheral surface of an inner race and an outer raceway provided on an inner peripheral surface of an outer race, are widely used for various precision rotating parts. Have been. Further, the radial ball bearing incorporated in the precision rotating part is used in a state where a predetermined preload is applied because it is necessary to support a rotating member such as a rotating shaft without play. Further, in order to keep the rigidity of the radial ball bearing at an appropriate value, it is necessary to regulate the bearing clearance of the radial ball bearing in the radial direction to a predetermined value. For this reason, it is necessary to measure the bearing clearance in the radial direction of the radial ball bearing.

In order to measure the bearing gap for such a purpose, conventionally, the outer ring is moved in the radial direction (radial direction) while the inner ring is fixed, and the displacement of the outer ring is measured to determine the bearing gap. Alternatively, the outer ring is moved in the axial direction (axial direction) while the inner ring is fixed to determine the axial clearance, and then the bearing clearance in the radial direction is calculated from the axial clearance.

[0004]

According to the conventional method for measuring the bearing clearance of a radial ball bearing as described above, a predetermined load is applied to a part of the outer ring at the time of measurement, so that the radial ball bearing including the outer ring is used. It is unavoidable that the components of the present invention are elastically deformed, and it is difficult to obtain a geometric bearing gap that should be originally obtained (without considering elastic deformation). Also, even if the bearing clearance originally required corresponds to the groove bottoms of the inner raceway and the outer raceway, there is no guarantee that the groove bottoms and the ball rolling surfaces are in contact with each other. Measurements cannot be obtained. Further, it takes time for the measurement, so that it is difficult to perform a 100% inspection in a manufacturing line of the radial ball bearing.
The method and apparatus for measuring the bearing clearance of a radial ball bearing according to the present invention have been invented to solve any of these problems.

[0005]

SUMMARY OF THE INVENTION Among the method and apparatus for measuring the bearing clearance of a radial ball bearing according to the present invention, the method for measuring the bearing clearance of a radial ball bearing according to claim 1 is as follows.
A plurality of balls are arranged between an inner ring raceway provided on the outer peripheral surface of the inner ring and an outer ring raceway provided on the inner peripheral surface of the outer ring, and a radial ball bearing having a predetermined preload applied to these balls is vibrated. In this state, the vibration of the inner ring or the outer ring is detected, and the bearing clearance in the radial direction of the radial ball bearing is obtained by calculation based on the frequency of the detected vibration.

A method of measuring a bearing clearance of a radial ball bearing according to a second aspect of the present invention is a method of measuring a radial gap of a radial ball bearing. The outer raceway is provided, and a plurality of balls are provided between the inner raceway and the outer raceway respectively. Preload is applied to the balls, and the radial clearance of a unit type radial ball bearing is measured. In a state where the bearing is vibrated in the radial direction and the axial direction, the vibration of the inner ring or the outer ring in the radial direction and the vibration in the axial direction are detected to determine the resonance frequency of the radial ball bearing,
By calculation based on the obtained resonance frequency, a preload is obtained in addition to obtaining the bearing clearance in the radial direction of the radial ball bearing.

According to a third aspect of the present invention, there is provided an apparatus for measuring a bearing clearance of a radial ball bearing, wherein a plurality of bearings are provided between an inner raceway provided on an outer peripheral surface of an inner race and an outer raceway provided on an inner peripheral surface of an outer race. A supporting device for supporting radial ball bearings, which are formed by arranging balls and applying a predetermined preload to these balls; a vibrator for vibrating the radial ball bearings supported by the supporting device; A vibration detector that detects the vibration of the inner ring or the outer ring of the radial ball bearing excited by the above, and a calculator that determines a bearing clearance in the radial direction of the radial ball bearing based on a detection value of the vibration detector. Prepare.

Further, the apparatus for measuring a bearing clearance of a radial ball bearing according to claim 4 is a radial ball bearing,
In particular, a double-row inner raceway is provided on the outer peripheral surface of the inner race, and a double-row outer raceway is provided on the inner peripheral surface of the outer race, and a plurality of balls are provided between the inner raceway and the outer raceway. The vibrator vibrates the radial ball bearing in the radial and axial directions, and the vibration detector detects the vibration in the radial direction. And a radial vibration detector for detecting vibration in the axial direction. The arithmetic unit determines a bearing clearance in the radial direction of the radial ball bearing based on the detected value of the vibration detector. Obtain the preload in addition to the demand.

[0009]

According to the method and the apparatus for measuring the bearing clearance of the radial ball bearing of the present invention having the above-described structure, the bearing clearance in the radial direction of the radial ball bearing can be measured quickly and accurately.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention corresponding to claims 1 and 3. Radial ball bearing 1 whose bearing clearance is measured according to the present invention
Is constituted by arranging a plurality of balls 6, 6 between an inner raceway 3 provided on the outer peripheral surface of the inner race 2 and an outer raceway 5 provided on the inner peripheral surface of the outer race 4, and by arranging them horizontally. A predetermined preload is applied to these balls 6, 6 by a load based on the weight of the outer race 4. Such a radial ball bearing 1 is externally fitted and supported on an intermediate portion of a support shaft 7 which is a support device. That is, the inner ring 2 is externally fitted to the upper half of the support shaft 7 by a clearance fit, and the lower end surface of the inner ring 2 is brought into contact with a step 8 formed at an intermediate portion of the support shaft 7, whereby The radial ball bearing 1 is horizontally supported at an intermediate portion of the support shaft 7. In this state, a load corresponding to the weight of the outer race 4 is applied to the balls 6, 6, and a preload based on the load is applied. A cylindrical fixing member 9 is externally fitted to a portion of the upper end of the support shaft 7 protruding from the upper end surface of the inner ring 2, and the lower end surface of the fixing member 9 is brought into contact with the upper end surface of the inner ring 2. In contact. During the measurement operation, the inner ring 2 is held between the lower end surface of the fixing tool 9 and the step portion 8 and is supported and fixed to the support shaft 7. Further, the base end surface (the lower end surface in FIGS. 1 and 3) of the support shaft 7 is fixedly connected to the upper surface of the vibrator 10 so that the radial ball bearing 1 supported by the support shaft 7 can be vibrated. .

On the other hand, a measurement terminal 12 of a vibration detector 11 is brought into contact with a lower end surface of the outer ring 4 so that vibration of the outer ring 4 of the radial ball bearing 1 excited by the vibrator 10 can be detected. And Then, a signal representing the value detected by the vibration detector 11 is input to the calculator 13. The computing unit 13 obtains a bearing clearance in the radial direction of the radial ball bearing 1 from the detected value based on the relationship described below.

According to the apparatus for measuring the bearing clearance of the radial ball bearing of the present invention configured as described above,
The bearing clearance in the radial direction of the radial ball bearing 1 can be measured quickly and accurately. First, while vibrating the radial ball bearing 1 by the vibrator 10, the vibration detector 1
1 by By detecting the vibration of the outer ring 4, determine the resonant frequency f _n of the radial ball bearing 1. And axial stiffness K _a of the radial ball bearing 1 constructed as described above, between the resonant frequency f _n, the floating mass m of the radial ball bearing _{1, f n = (K a} / m) 1/2 / (2π) Further, the bearing gap over the radial direction of the radial ball bearing 1, and axial stiffness K _a, between the axial load leading to preload, there is a relation as shown in FIG. Therefore, by running a program incorporating the relationship as shown in the above equation and the relationship as shown in FIG. 2 on the microcomputer constituting the arithmetic unit 13,
Based on the resonance frequency f _n of the radial ball bearing 1 in which the vibration detector 11 detects the bearing gap over the radial direction of the radial ball bearing 1, can be obtained easily and quickly. In addition, since the measurement itself is performed under a very small load state and a substantially uniform load state in the circumferential direction, there is no deviation in measured values due to local deformation of each component of the radial ball bearing 1, and accurate measurement work can be performed. .

Next, FIG. 3 shows a second embodiment of the present invention, which also corresponds to the first and third aspects of the present invention. In this example, when the measuring terminal 12 of the vibration detector 11 is brought into contact with the lower end surface of the outer ring 4 as it is and the mass of the outer ring 4 is small, a predetermined load that leads to the application of a preload to the balls 6, 6. Is applied when it cannot be given. For this reason, in the case of this example, a weight 14 for a preload is externally fitted to the outer ring 4 and a vacuum chuck or an electromagnetic chuck (not shown) is used.
The weight 14 is fixed to the outer race 4. In the case of this example, a load required for applying a preload is applied by the weight 14, so that measurement is possible even when the mass of the outer ring 4 is small. Other configurations and operations are the same as those of the above-described first example.

FIGS. 4 and 5 show a third embodiment of the present invention corresponding to claims 2 and 4. FIG. The unit type radial ball bearing 1a for measuring the radial clearance and the preload according to the present embodiment has a pair of radial ball bearings 1, 1 incorporated between the outer peripheral surface of the shaft 15 and the inner peripheral surface of the housing 16. A small-diameter portion 17 is formed at an intermediate portion of the inner peripheral surface of the housing 16, and among the outer rings 4, 4 constituting the radial ball bearings 1, 1, the opposite end faces are formed by:
The small diameter portion 17 is in contact with both end surfaces in the axial direction. or,
The inner races 2, 2 constituting each of the ball bearings 1, 1 are connected to the shaft 15.
Are fitted and fixed externally to the intermediate portion by a tight fit. In this state, a plurality of balls 6, 6 provided between the inner raceways 3, 3 and the outer raceways 5, 5, respectively, are preloaded. In the case of this example, each of the ball bearings 1 is a back combination (DB type).

The lower end surface of the shaft 15 is connected and fixed to the upper end surface of the support shaft 7 by screws 18. The lower end surface of the support shaft 7 is connected to the vibrator 10a. The vibrator 10a generates vibrations in both the radial and axial directions, and vibrates the radial ball bearing 1a in the radial and axial directions via the support shaft 7 during operation.

The vibration detector 11a for detecting the vibration of the radial ball bearing 1a is a radial vibration detector 19a.
And an axial vibration detector 20. The radial vibration detector 19 is transmitted to the housing 16 from the outer races 4, 4 constituting the ball bearings 1, 1 by bringing the measurement terminals 12 a into contact with the outer peripheral surface of the intermediate portion of the housing 16. Vibration in the radial direction can be measured freely. The axial vibration detector 20 is configured such that the measurement terminal 12b is brought into contact with the axial end surface (the lower end surface in the illustrated example) of the housing 16 so that each of the ball bearings 1,
Vibration in the axial direction transmitted from the outer races 4 and 4 constituting the housing 1 to the housing 16 can be measured.
The signals representing the detected values of the vibration detector 11a, which is composed of both the radial and axial vibration detectors 19 and 20, are input to a calculator 13 (see FIGS. 1 and 3; omitted in FIG. 4). The computing unit 13 obtains a preload (kgf) in addition to the bearing clearance in the radial direction of the radial ball bearing 1a from the detected value based on the relationship described below.

According to the apparatus for measuring the bearing clearance of the radial ball bearing of the present invention configured as described above,
The bearing clearance in the radial direction of the radial ball bearing 1 can be measured quickly and accurately. First, while vibrating the radial ball bearing 1a by the vibrator 10a, the outer ring 4,
Radial from 4 transmitted to the housing 16, by detecting the vibration of the axial directions, obtaining the resonant frequency f _n of the radial ball bearing 1. And rigidity K of the radial ball bearing 1a of the unit type constituted as described above, between the resonant frequency f _n, the floating mass m of the radial ball bearing _{1, f n = (K /} m) 1/2 / (2π) This relationship, the stiffness K _r over the radial direction, even concerning to any rigid K _a over the axial direction as well established. Further, between the bearing clearance in the radial direction of the radial ball bearing 1a, the rigidity K, and the preload,
There is a relationship as shown in FIG.

Therefore, a program incorporating the relationship as shown in the above equation and the relationship as shown in FIG.
By actuating on a microcomputer constituting the 3, based on the resonant frequency f _n of the radial ball bearing 1a of the vibration detector 13 detects the bearing clearance and preload over the radial direction of the radial ball bearing 1a Can be easily and quickly obtained. That is, the vibration detector 1
1a, the rigidity K of the radial ball bearing 1a in the radial direction is calculated from the above equation based on the resonance frequency in the radial direction obtained from the value detected by the radial vibration detector 19.
_{Find r} . Similarly, based on the resonant frequency for the axial direction obtained from the detection value of the axial vibration detector 20 determines the stiffness K _a over the axial direction of the radial ball bearing 1a from the above equation. Then, from the over stiffness K _r and over the axial direction stiffness K _a thereto radially, from the relationship such as shown in FIG. 5, obtains the bearing clearance and preload over to the radial direction. That is, applying the over stiffness K _r and rigidity K _a over the axial direction thereof radially Figure 5, these two rigid K _r, a bearing clearance and preload over the radial direction corresponding to the intersection of the straight line representing the K _a , The bearing clearance and the preload of the radial ball bearing 1a. Since the measurement itself performed in this manner is performed with the same preload as during use, there is no deviation in measured values due to local deformation of each component of the radial ball bearing 1a, and accurate measurement can be performed.

When the specifications of the pair of radial ball bearings 1 and 1 constituting the unit type radial ball bearing 1a are different from each other, as shown in FIG. 6, the resonance frequency value becomes f _n1. , F _n2 . Therefore, in such a case, the rigidities K _r1 and K _{r2 in the} radial direction and the rigidities K _a1 and K _{a2 in the} axial direction are obtained based on the values of the two resonance frequencies f _n1 and f _n2 , respectively. Based on the values, the radial clearance and preload of each of the ball bearings 1 and 1 are obtained from the relationship shown in FIG. Note that the four dashed lines shown in FIG. 5 indicate a state where the values of the rigidities K _r1 , K _r2 , K _a1 , and K _a2 are input.

[0020]

The method and apparatus for measuring the bearing clearance of a radial ball bearing according to the present invention are constructed and operated as described above, but can quickly and accurately measure the bearing clearance in the radial direction of a radial ball bearing. Therefore, it is possible to measure all the bearing gaps in the radial ball bearing manufacturing line, and it is possible to stratify a large number of radial ball bearings according to the size of the bearing gap.

[Brief description of the drawings]

FIG. 1 is a partially cut-away schematic side view showing a first example of an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a bearing clearance in a radial direction of a radial ball bearing, axial rigidity, and a preload amount.

FIG. 3 is a partially cut-away schematic side view showing a second example of the embodiment of the present invention.

FIG. 4 is a partially cut schematic side view showing the third example.

FIG. 5 is a diagram showing a relationship between a bearing gap in a radial direction of a unit type radial ball bearing, radial and axial rigidities, and a preload amount.

FIG. 6 is a diagram showing a resonance frequency generated when a pair of radial ball bearings constituting a unit type radial ball bearing have different specifications.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Radial ball bearing 2 Inner ring 3 Inner ring track 4 Outer ring 5 Outer ring track 6 Ball 7 Support shaft 8 Step 9 Fixture 10, 10a Vibrator 11, 11a Vibration detector 12, 12a, 12b Measurement terminal 13 Calculator 14 Weight 15 Shaft 16 Housing 17 Small diameter part 18 Screw 19 Radial vibration detector 20 Axial vibration detector

Claims (4)

[Claims] 1. A radial bearing comprising a plurality of balls arranged between an inner raceway provided on an outer peripheral surface of an inner race and an outer raceway provided on an inner peripheral surface of an outer race, wherein a predetermined preload is applied to these balls. In a state where the ball bearing is vibrated, the vibration of the inner ring or the outer ring is detected, and a calculation based on the frequency of the detected vibration is used to obtain a bearing clearance in the radial direction of the radial ball bearing. How to measure. 2. A radial ball bearing comprising: a plurality of rows of inner ring raceways provided on an outer peripheral surface of an inner ring; and a plurality of rows of outer ring raceways provided on an inner peripheral surface of an outer ring. A unit type radial ball bearing in which a plurality of balls are pre-loaded, and in a state where the radial ball bearing is vibrated in the radial direction and the axial direction, vibration and axial vibration of the inner ring or the outer ring in the radial direction are performed. The method according to claim 1, further comprising: detecting vibrations in said directions to obtain a resonance frequency of said radial ball bearing; and calculating a preload in addition to obtaining a bearing clearance of said radial ball bearings in the radial direction by an operation based on the obtained resonance frequency. The method for measuring the bearing clearance of the radial ball bearing described in 1. 3. A radial bearing having a plurality of balls disposed between an inner raceway provided on an outer peripheral surface of an inner race and an outer raceway provided on an inner peripheral surface of an outer race, wherein a predetermined preload is applied to these balls. A support device that supports the ball bearing, a vibrator that vibrates the radial ball bearing supported by the support device, and detects vibration of the inner ring or the outer ring of the radial ball bearing that is vibrated by the vibrator. An apparatus for measuring a bearing clearance of a radial ball bearing, comprising: a vibration detector; and a calculator for calculating a bearing clearance in a radial direction of the radial ball bearing based on a detection value of the vibration detector. 4. A radial ball bearing is provided with a double row of inner ring raceways on an outer peripheral surface of an inner ring, and a double row of outer ring raceway on an inner peripheral surface of an outer ring, and is provided between each of the inner ring raceways and the outer ring raceway. A unit-type radial ball bearing in which a plurality of balls are preloaded, a vibrator vibrates the radial ball bearing in the radial direction and the axial direction, and a vibration detector includes a radial direction. And a radial vibration detector for detecting vibrations in the axial direction. The computing unit extends in the radial direction of the radial ball bearing based on a detection value of the vibration detector. 4. The apparatus for measuring a bearing clearance of a radial ball bearing according to claim 3, wherein a preload is determined in addition to determining the bearing clearance.