JP2003329512A - Apparatus and method for measurement of natural oscillation frequency of roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus for a natural oscillation frequency of a roller bearing by which the natural oscillation frequency of the bearing subjected to a preload is measured simply and in a short period of time even in a production line of the bearing, and which surely prevents a resonance from being generated in an apparatus with the built-in bearing, and to provide a measuring method for the natural oscillation frequency of the roller bearing. <P>SOLUTION: An inner ring of a ball bearing (the roller bearing) 50 as a measuring object is fixed to a fixed base 2, and a plumb bob (a preload application member) 3 used to load a prescribed preload to the ball bearing 50 in its axial direction is attached integrally to an outer ring of the ball bearing 50 in a state levitated from the fixed base 2. A blow is applied to a prescribed place P on the fixed base 2, and a vibration of the plumb bob 3 due to the blow is measured by a measuring unit (a measuring means) 4. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device and a measuring method for measuring a natural vibration frequency of a rolling bearing used in information equipment such as a hard disk drive (HDD) device.

[0002]

2. Description of the Related Art For example, in HDD devices, rolling bearings such as ball bearings are used in the rotation support portion of a magnetic disk that is driven to rotate by a spindle motor, the pivot portion of a magnetic head assembly, and the like. There is. In such a rolling bearing, in order to prevent rattling of a rotating body, for example, a magnetic disk, usually, a preload is applied in an axial direction in the device. However, if the natural vibration frequency of the rolling bearing matches the natural vibration frequency of the other components, resonance may occur and abnormal vibration may occur, which may hinder the reading and writing of data on the magnetic disk. Therefore, by changing the material, shape, etc. of each component, the natural vibration frequency of the rolling bearing and the natural vibration frequency of the other components are shifted to avoid resonance.

However, the natural vibration frequency of the rolling bearing greatly varies from product to product, and in the conventional measuring apparatus and method, in general, the bearing to be measured is measured by using an exciter equipped with a motor. Since the natural vibration frequency was measured in a vibrating state, the measuring device was complicated, and it took time and effort to measure the natural vibration frequency of each bearing on a bearing production line. It was practically difficult. As a result, there is a problem in that it is not possible to effectively prevent resonance from occurring in the device in which the bearing manufactured in the actual production line is incorporated.

In view of the above-mentioned conventional problems, the present invention can easily measure the natural vibration frequency of a bearing to which a preload has been applied, even in a bearing production line or the like. An object of the present invention is to provide a measuring device and a measuring method for a natural vibration frequency of a rolling bearing, which can surely prevent resonance from occurring in a device incorporating the bearing.

[0005]

A natural vibration frequency measuring device for a rolling bearing according to the present invention is a rolling device provided with an inner ring and an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. A device for measuring a natural vibration frequency of a bearing, which is integrally attached to a fixed base for fixing one of the inner ring and the outer ring to the other ring ring of the inner ring and the outer ring, and to the rolling bearing. And a preload applying member for applying a predetermined preload in the axial direction, and a measuring means for measuring a vibration generated by a striking applied to an arbitrary portion of the fixing base or the preload applying member, and performing a frequency analysis of the measured vibration. Is provided (Claim 1).

In the apparatus for measuring the natural vibration frequency of the rolling bearing configured as described above, the fixing base fixes one race ring of the rolling bearing to be measured, and the preload applying member fixes the other race ring of the bearing. By attaching it integrally to
It is possible to simply configure a vibration system in which the fixed base, the preload applying member, and the bearing to which the preload is applied are integrated. Further, the measuring means measures the vibration generated by the impact and analyzes the frequency of the vibration, whereby the natural vibration frequency of the bearing to which the preload is applied can be measured.

Further, in the measuring device for measuring the natural vibration frequency of the rolling bearing (claim 1), the preload applying member is
It may be constituted by a weight integrally attached to the other bearing ring in a state of being floated from the fixed base (claim 2). In this case, the weight can apply an axial preload to the rolling bearing to be measured, and can configure the vibration system including the bearing.

Further, the method for measuring the natural vibration frequency of a rolling bearing according to the present invention provides a method for measuring the natural vibration frequency of a rolling bearing including an inner ring and an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. A measuring method, wherein one of the inner race and the outer race is fixed to a fixed base, and the other race is fixed to a preload applying member, and the predetermined preload is axially applied to the rolling bearing by the preload applying member. Is applied to the fixing table or the preload applying member, the vibration generated by the impact is measured, and the frequency of the vibration is analyzed (claim) Item 3).

In the method of measuring the natural vibration frequency of the rolling bearing configured as described above, one and the other races are fixed to the fixed base and the preloading member for the rolling bearing to be measured, respectively. It is possible to simply configure a vibration system in which the fixing base and the preload applying member are integrated with the bearing to which the preload is applied. Furthermore, the impact can be applied to the fixed base or the preload applying member to vibrate the vibration system, and the vibration can be measured and the frequency of the vibration can be analyzed to identify the preload of the bearing. The vibration frequency can be measured.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments showing a measuring apparatus and a measuring method of a natural vibration frequency of a rolling bearing of the present invention will be described below with reference to the drawings. FIG. 1 is a structural diagram showing a configuration example of a main part of a device for measuring a natural vibration frequency of a rolling bearing according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing a mounting portion of a rolling bearing in the measuring device. . 1 and 2, the measuring device 1 of the present embodiment is a preloading member that axially applies a predetermined preload to a metal fixing base 2 and a ball bearing 50 as a rolling bearing to be measured. The weight 3 and the measuring unit 4 as a measuring unit for measuring the vibration of the weight 3. The ball bearing 50 includes an inner ring 50a and an outer ring 50b,
It has a plurality of balls 50c as rolling elements arranged rotatably between these inner and outer rings, and is incorporated in an information device such as an HDD device so as to rotatably support a rotating body. Specifically, the inner ring 50a and the outer ring 50b
Are attached to, for example, a spindle of a spindle motor of the HDD device and a motor hub on which a magnetic disk is integrally rotatably mounted, and smoothly support disk rotation by the motor. Further, in the case of supporting the magnetic disk as described above, the ball bearing 50 is incorporated into the HDD device in a state where a preload is applied, and rattling is prevented from occurring in the disk.

The fixed base 2 is provided with a disk-shaped base portion 2a disposed on a vibration isolation base 7 with a vibration isolation rubber 6 interposed therebetween, and a bolt 5 so as to be detachably attached to the base portion 2a. The inner ring 50a of the ball bearing 50 is provided with a shaft portion 2b having a tip portion through which the inner ring 50a is inserted, and a cylindrical pressing member 2c for pressing the inner ring 50a toward the base portion 2a. The ball bearing 50 is fixed by being integrally attached to the portion 2b. Specifically, as shown in FIG. 2, the tip end portion of the shaft portion 2b has an annular support surface 2b1.
And a circumferential surface 2b2 provided at a right angle to the support surface 2b1.
The inner ring 50a is attached to the tip portion in a state where the axially lower end surface and the inner peripheral surface thereof are in contact with the support surface 2b1 and the circumferential surface 2b2, respectively.
Further, the pressing member 2c is tightened to the base portion 2a side by the tightening screw 2f in a state where the annular end surface 2c1 formed on the lower opening side thereof is brought into contact with the axially upper end surface of the inner ring 50a. ing. The tightening screw 2f is sequentially inserted through the washer 2e, the O-ring 2d, and the through hole 2c2 on the upper opening side of the pressing member 2c, and into the bolt hole 2b3 provided in the central portion of the tip portion of the shaft portion 2b. By screwing the inner ring 50 between the support surface 2b1 and the end surface 2c1.
Hold a in a stable state.

The weight 3 is provided with an inner peripheral surface 3a1 (FIG. 2) in contact with the outer peripheral surface of the outer ring 50b, a ring-shaped portion 3a arranged outside the outer peripheral surface of the outer ring, and the ring-shaped portion. An annular end surface 3b1 that is fixed to the outer ring 50b on the upper side in the axial direction while being fixed to the outer ring 50b by bolts 8
(FIG. 2), and is attached integrally to the outer ring 50b in a state of being floated from the fixed base 2. By attaching to the outer ring 50b in this way, the weight 3 applies a predetermined preload to the ball bearing 50 by its own weight, and at the same time, the inner ring 50a of the ball bearing 50 is loaded.
Also, the internal clearance set between the outer ring 50b and the ball 50c is eliminated, the ball 50c and the inner and outer rings are integrated, and the fixed base 2 holds the ball bearing 50. Also,
By fixing the weight 3 in a state of being floated from the fixed base 2 as described above, a predetermined preload can be accurately applied to the ball bearing 50 in the axial direction.

The measuring unit 4 comprises a cylindrical portion 3 of the weight 3.
An acceleration pickup 4a as a vibration measuring member attached to the upper end of b, a charge amplifier 4b for amplifying a detection signal from the acceleration pickup 4a, and a fast Fourier transform process on the detection signal from the charge amplifier 4b, FFT4c for frequency analysis of measured vibration
It has and. When the weight 3 vibrates, the acceleration pickup 4a outputs a detection signal indicating the acceleration of the vibration. In addition to the amplifier that amplifies the detection signal, the charge amplifier 4b is provided with a filter such as a bandpass filter that removes noise of the detection signal to improve the accuracy of vibration detection. In addition, the FF
A display unit (not shown) is connected to T 4c so as to display the analysis result of the FFT 4c. In addition to the above description, instead of the acceleration pickup 4a, a velocity sensor and a displacement sensor that detect the velocity and displacement of the vibration of the weight 3 may be used as the vibration measuring member.

In the measuring device 1 configured as described above,
By fixing the inner ring 50a of the ball bearing 50 to the fixed base 2 and the weight 3 to the outer ring 50b, the ball bearing 50 is attached to the device 1 in a state in which a predetermined preload is applied, and these fixed bases 2, A vibration system in which the weight 3 and the ball bearing 50 are integrated is configured. Then, with respect to the vibration system including the ball bearing 50 to which the preload is applied in this manner, for example, by the vibration hammer 9 (FIG. 1), an arbitrary position P of the fixed base 2
When a shock is applied to (Fig. 1), this vibration system vibrates. That is, the applied impact is transmitted as vibration from the fixed base 2 to the weight 3 via the ball bearing 50, and the vibration acceleration is detected by the acceleration pickup 4a.

Subsequently, the detected vibration acceleration is the charge amplifier 4 as a detection signal from the acceleration pickup 4a.
It is output to the FFT 4c via b. And FFT 4
The frequency of the detection signal input by c is analyzed, the vibration level at a frequency component of a predetermined frequency unit is obtained, and the analysis result of the vibration frequency shown by the curve 20 in FIG. 3 is displayed on the display section. Here, in the curve 20, the peak value of the frequency component having the maximum vibration level is the result of resonance at the natural vibration frequency of the vibration system when the vibration propagates in the vibration system, and The frequency is such that the inner ring 50a of the ball bearing 50 is fixed to the fixed base 2 and the outer ring 50b.
It has been found that the weight 3 is integrally attached to the ball bearing 50 so that it matches the natural vibration frequency Fc of the ball bearing 50 to which a preload is always applied. In this way, the measurement unit 4 measures the vibration of the weight 3 and performs the frequency analysis, so that the natural vibration frequency Fc of the ball bearing 50 to which the preload is applied can be obtained.

In the measuring apparatus 1 and the measuring method of the present embodiment configured as described above, the weight 3 is integrally attached to the outer ring 50a of the ball bearing 50 to be measured whose inner ring 50a is fixed to the fixed base 2. By doing so, the ball bearing 50 to be measured
A simple vibration system in which the fixed base 2 and the weight 3 and the preloaded ball bearing 50 are integrated while holding a predetermined preload in the axial direction with respect to You can Moreover, for example, the operator can vibrate the vibration system by a single impact applied to the arbitrary position P of the fixed base 2 by using the vibration hammer 9 manually, and further, the measurement unit 4 is weighted. By measuring the vibration of No. 3 and analyzing the vibration frequency, the preloaded ball bearing 5
Since the natural vibration frequency Fc of 0 can be obtained, unlike the above-mentioned conventional example using the vibrator with the motor, the production line of the ball bearing 50 and the HD in which the ball bearing 50 is incorporated.
The natural vibration frequency of each of the ball bearings 50 can be easily measured in a short time even at the assembly work site of the D device. As a result, the data collected in advance by the measuring apparatus 1 and the measuring method of the present embodiment even in the above-mentioned production line (for example, the measurement data of the natural vibration frequency of the ball bearing that resonated when incorporated in the HDD device). ), The ball bearing 50
It is possible to easily assume whether or not resonance will occur in the HDD device in which the ball bearing 50 is incorporated before it is incorporated in the HDD device, and it is possible to reliably prevent resonance in the HDD device. Therefore, it is possible to easily configure the HDD device in which problems such as read / write error, abnormal vibration, and abnormal sound caused by resonance are prevented.

Further, in this embodiment, a predetermined preload is applied to the ball bearing 50 to be measured by the weight 3 integrally attached to the outer ring (the other race ring) 50b in a state of being floated from the fixed base 2. Since the preload applying member for applying in the axial direction is configured, the member for applying the axial preload to the ball bearing 50 also serves as the member for configuring the vibration system including the ball bearing 50. Therefore, the structure of the measuring device can be simplified, and the structure of the vibration system can be simplified, so that the measurement accuracy of the natural vibration frequency of the bearing can be improved.

In the above description, the case where the inner ring 50a is fixed to the fixed base 2 and the weight 3 is fixed to the outer ring 50b has been described. However, the present invention applies a predetermined preload to the rolling bearing to be measured in the axial direction. The outer ring 50b may be fixed to the fixed base 2 and the weight 3 may be attached to the inner ring 50.
It may be fixed to a. Further, in the above description, the shaft portion 2b
The inner ring 50 is in contact with the inner circumferential surface 2b2 of the inner ring 50
Although the configuration in which a is inserted into the tip portion of the shaft portion 2b has been described, it is sufficient if the axially lower end surface of the inner ring 50a is in contact with the support surface 2b1 of the shaft portion 2b.
With the inner ring inner peripheral surface separated from the inner ring 50a,
May be attached to. Further, in the above description, the configuration in which the inner peripheral surface 3a1 of the ring-shaped portion 3a of the weight 3 is in contact with the outer peripheral surface of the outer ring has been described. As long as a predetermined preload can be applied to the rolling bearing to be measured in the axial direction, the structure and shape of the weight 3 are not limited to the above. Further, in the above description, a configuration is described in which the arbitrary point P of the fixed base 2 is hit and the vibration of the weight 3 is measured by the acceleration pickup 4a attached to the weight (preload applying member) 3. However, the present invention is not limited to this. What is necessary is just to measure the vibration of the vibration system including the rolling bearing to be measured, and the vibration is measured by the vibration measuring member attached to the fixed base 2 by striking an arbitrary portion of the preload applying member. Alternatively, the vibration measuring member attached to the fixed base 2 may be used to measure the vibration caused by the impact applied to the fixed base 2.

[0019]

The present invention constructed as described above has the following effects. According to the natural vibration frequency measuring device for a rolling bearing of claim 1, the fixed base and the preload applying member hold the bearing in a state in which the rolling bearing to be measured is preloaded, so that these fixed bases are Preloading member,
Also, a vibration system in which the above-mentioned bearing to which a preload is applied is integrated can be easily configured. Furthermore, the measuring means,
By measuring the vibration generated by impact and analyzing the frequency of the vibration, it is possible to measure the natural vibration frequency of the above-mentioned bearing to which the preload is applied, so it is possible to measure without using an exciter equipped with a motor. The rolling bearing can be vibrated and the natural vibration frequency can be measured. Therefore, the natural vibration frequency of the bearing can be easily measured in a short time even in the bearing production line. As a result, it is possible to reliably prevent the occurrence of resonance in the HDD device or the like.

According to the natural vibration frequency measuring device of the rolling bearing of the second aspect, the weight can apply an axial preload to the rolling bearing to be measured and includes the bearing. Since the vibration system can be configured, the configuration of the measurement device can be simplified.

According to the method of measuring the natural vibration frequency of the rolling bearing of the third aspect, the fixed base and the preload applying member and the rolling bearing to be measured to which the preload is applied are provided by the fixed base and the preload applying member. An integrated vibration system can be easily configured, and moreover, by measuring the vibration generated by the impact and performing a frequency analysis of the vibration,
Since it is possible to measure the natural vibration frequency of a bearing to which a preload is applied, unlike the above-mentioned conventional example that uses a vibrator equipped with a motor, the natural vibration frequency of the bearing can be easily calculated even in the production line of the bearing. In addition, it is possible to perform the measurement in a short time, and thus it is possible to reliably prevent the occurrence of resonance in the device.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a configuration example of a main part of a device for measuring a natural vibration frequency of a rolling bearing according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a mounting portion of a rolling bearing in the measuring device.

FIG. 3 is a graph showing an example of measurement of a vibration frequency by the measuring device.

[Explanation of symbols]

1 Measuring device 2 fixed base 3 Weight (preloading member) 4 Measuring unit (measuring means) 50 ball bearings (rolling bearings) 50a Inner ring (race ring) 50b outer ring (race ring) 50c ball (rolling element)

Claims (3)

[Claims] 1. A device for measuring a natural vibration frequency of a rolling bearing including an inner ring and an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring, wherein one of the inner ring and the outer ring is a track. A fixed base for fixing the ring, a preload applying member that is integrally attached to the other race ring of the inner ring and the outer ring, and that applies a predetermined preload to the rolling bearing in the axial direction, the fixed base or the An apparatus for measuring a natural vibration frequency of a rolling bearing, comprising: a measuring unit that measures a vibration generated by an impact applied to an arbitrary portion of a preload applying member and analyzes the frequency of the measured vibration. 2. The preload applying member is constituted by a weight integrally attached to the other bearing ring in a state of being floated from the fixed base.
A device for measuring the natural vibration frequency of the rolling bearing described. 3. A method of measuring a natural vibration frequency of a rolling bearing including an inner ring and an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring, wherein one orbit of the inner ring and the outer ring. The fixed base or the preload applying member in a state in which a ring is fixed to a fixed base, and the other race is fixed to a preload applying member, and a predetermined preload is axially applied to the rolling bearing by the preload applying member. A method for measuring the natural vibration frequency of a rolling bearing, characterized in that a vibration is generated by the impact, and the frequency of the vibration is analyzed.