JPH05126628A - Vibration measuring device - Google Patents

Abstract

PURPOSE:To provide a vibration measuring device capable of inspecting a small bearing structure with high precision. CONSTITUTION:A vibration measuring device measures the vibration of a bearing structure provided with multiple balls along the peripheral direction between inner and outer members which are made rotatable each other. The outer member of the bearing structure is received by the rotatable receiving member 5 of a rotary system 6. A pressing piece 10 kept in contact with the inner member is pressed by a pressing means 11 to apply the preset pressure to the bearing structure. The receiving member 5 is rotated by a rotation driving means 9 to rotate the outer member. The vibration acceleration of the bearing structure is detected by a detector 12 provided on the pressing piece 10, and whether the detected acceleration is the preset level or below is judged by a judging means 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration measuring device.

[0002]

2. Description of the Related Art In general, a bearing structure in which a plurality of balls arranged along the circumferential direction are interposed between inner and outer members so that the inner and outer members are rotatable relative to each other, specifically, for example, When manufacturing a ball bearing having inner and outer races and balls interposed between the inner and outer races, inspection for the presence or absence of scratches on the balls and the like, inspection for dust noise (sound generated by mixing foreign matter) , And NRRO had to be checked.

However, as a conventional inspection method, the inner ring or the outer ring is rotated and the displacement (amplitude) of the vibration of the outer ring or the inner ring which is not rotating is inspected.

[0004]

However, in a small bearing, its natural frequency is high, and if the frequency is high, the sensitivity is decreased and the accurate inspection cannot be performed.

Therefore, an object of the present invention is to provide a vibration measuring device capable of inspecting a bearing structure such as a small bearing with high accuracy.

[0006]

In order to achieve the above-mentioned object, a vibration measuring device according to the present invention has a plurality of balls arranged along the circumferential direction which are interposed between inner and outer members. A vibration measuring device for measuring vibration of a bearing structure in which members are rotatable with respect to each other, the rotating mechanism having a rotatable receiving member for receiving an inner member or an outer member, and a cushioning material for holding the rotating mechanism. Attached holding base, rotation driving means for rotating the receiving member of the rotating mechanism to rotate the inner member or the outer member, a pressing member for press-contacting the non-rotating outer member or inner member, and the pressing member Pressurizing means for applying a predetermined pressure to the bearing structure, a detector connected to the presser for detecting vibration acceleration, and a determining means for determining whether or not the detected acceleration is below a predetermined level. And, it is equipped with.

[0007]

The inner member or the outer member is rotated by the rotating mechanism, and the pressing member is pressed to the outer member or the inner member which is not rotating by the pressurizing means to apply a predetermined pressure to the bearing structure. Then, the vibration acceleration can be detected by the detector.

Then, the discriminating means judges whether or not the acceleration level is equal to or lower than a predetermined level. If the acceleration level is equal to or lower than the predetermined level, it is determined as a good product, and if it is equal to or higher than the predetermined level, it is determined as a defective product.

By the way, in general, the vibration velocity is a displacement amount per unit time, and V (t) = A · 2πfcos2π
The vibration acceleration is a variable in the velocity per unit time, and a (t) = − A · (2πf) ² si
It is represented by n2πft. f is the frequency, A is a constant, and t is time.

Therefore, the velocity amplitude is 2πfA, the acceleration amplitude is (2πf) ² A, and the acceleration amplitude is
Since the frequency becomes larger as the frequency increases, if the inspection is performed by acceleration as in the present invention, the sensitivity becomes large and the quality can be surely judged.

[0011]

The present invention will be described in detail below with reference to the drawings illustrating the embodiments.

FIG. 1 shows an overall simplified view of a vibration measuring device according to the present invention, which measures the vibration of a bearing structure 1 (see FIG. 2).

As shown in FIG. 2, the bearing structure 1 has a plurality of balls 2 arranged in the circumferential direction interposed between the inner and outer members 3 and 4, and the inner and outer members 3 and 4. Reference numeral 4 denotes a ball bearing in which the inner member 3 is an inner ring and the outer member 4 is an outer ring.

This device, as shown in FIG.
A rotating mechanism 6 having a rotatable receiving member 5 for receiving the inner member 3 or the outer member 4, a holding table 8 with a cushioning material 7 for holding the rotating mechanism 6, and a rotation drive for rotating the receiving member 5 of the rotating mechanism 6. Means 9 and non-rotating outer member 4 or inner member 3
A pressing member 10 that is in pressure contact with the pressing member 10, pressing means 11 that presses the pressing member 10 to apply a predetermined pressure to the structure 1, and a detector 12 that is connected to the pressing member 10 and that detects vibration acceleration. A discriminating means 13 for discriminating whether or not the detected acceleration is below a predetermined level,
Etc., and if the detected acceleration is equal to or higher than a predetermined level, it is determined as a defective product.

The rotating mechanism 6 is a main body attached to the holding table 8.
14 and the receiving member 5 that is rotatably supported by the main body 14.

The receiving member 5 is, as shown in FIG.
A fitting recess 16 is provided in the upper end surface 15, and the bearing structure 1 is fitted in the fitting recess 16. This mating recess 16
A recess 17 for escape is provided on the lower surface of the.

That is, as shown in FIG. 2, the outer member 4 is fitted into the fitting recess 16 and the inner member 3 is brought into non-contact with the receiving member 5, so that the bearing structure 1 receives the receiving member. Received by 5.

Next, the rotation driving means 9 is operated by the driving motor 18
And a transmission mechanism 19 for transmitting the rotational driving force of the drive motor 18 to the member 5.

The transmission mechanism 19 includes a pulley 20 attached to the output shaft of the drive motor 18 and a main body 14 of the rotation mechanism 6.
21 which is attached to and is linked to the receiving member 5
And a belt 22 wound around the pulleys 20 and 21.

Therefore, when the drive motor 18 is driven, the pulley 20 rotates, and this rotation causes the pulley 21 to rotate via the belt 22, which causes the receiving member 5 to rotate about its axis.

The holding table 8 is held by the main body frame 23 via the cushioning material 7 made of anti-vibration rubber or the like, the mounting frame 24 is erected on the main body frame 23, and the driving motor is mounted on the mounting frame 24. 18 is installed.

As shown in FIG. 2, the pusher 10 is composed of a tip spherical body portion 10a and a main body portion 10c connected to the spherical body portion 10a via a tapered portion 10b.
The detector 12 is connected to the.

That is, in the pressing member 10, the spherical portion 10a is inserted into the inner member 3 in a state where the tapered portion 10b is in contact with the upper end edge of the inner peripheral surface 3a of the inner member 3, and the bearing structure 1 is indicated by the arrow A. Press in the direction.

Thus, the detector 12 uses a piezoelectric conversion element and detects the acceleration of vibration of the bearing structure 1 received via the pressing element 10.

The pressurizing means 11 includes a shaft 25 standing on the holding table 8, a block body 26 attached to the shaft 25, and a guide frame body 27 attached to the block body 26.
A cylinder 28 attached to the guide frame 27 so as to be movable up and down as shown by an arrow, a slide table 29 attached to the cylinder 28, and an arm 30 protruding from the slide table 29.
And the detector 12 is held by the arm 30.

That is, the positioning of the block body 26 roughly positions the pressing element 10, and the cylinder 28 is moved up and down along the guide rod 31 of the guide frame 27 to position the pressing element 10 with high accuracy. To do.

In order to position the block body 26, the shaft 25 is used as a screw rod, the slide body 26 is used as a nut member that is screwed into this screw rod, and the shaft 25 is rotated about its axis to move the block body 26. It is also preferable to move up and down.

The cylinder 28 moves up and down by air supply / discharge from an air supply device (not shown).

A frequency analyzer 32 is connected to the detector 12. The frequency analyzer 32 has a high pass filter 33 and a low pass filter 34, and in this embodiment,
The high pass filter 33 passes 1kHz or more,
The low-pass filter 34 passes the light of 15 KHz or less.

Therefore, a frequency band of 1 KHz to 15 KHz passes.

Then, 1 KH passed through the frequency analyzer 32
Within the range of z to 15 KHz, the discriminating means 13 discriminates whether or not the acceleration level at a certain frequency is lower than the reference (predetermined) level. In the embodiment, 3 KHz and 7 KHz
The acceleration level at is determined.

That is, the level of the frequency to be discriminated is set by the reference setter 35, and the discriminating means 13 is set from the reference setter 35.
A reference value is input to and the detected acceleration level is compared with the reference value.

Then, the determined result is displayed on the display means 36. That is, if the level of vibration acceleration is higher than a predetermined level, it is a defective product, and a defective display is made. If it is smaller than the predetermined level, it is a good product and a good display is made.
It is also preferable that the display is not performed when the result is good and the display is performed only when the result is bad.

Therefore, as the display means 36, an indicator lamp whose color is different between good and defective is illuminated, an indicator lamp is illuminated only when defective, and the letters "good" and "bad" are displayed. There are various types such as Furthermore, in the case of a defect, it is also preferable to generate a sound notifying that the defect is defective.

Next, a method of inspecting the bearing structure 1 using the vibration device constructed as described above will be described.

First, as shown in FIG. 2, the bearing structure 1 is
It is fitted in the fitting recess 16 of the receiving member 5, and the pusher 10 is lowered via the pressurizing means 11 to form a spherical portion of the pusher 10.
10a is inserted into the inner member 3, the tapered portion 10b is pressed against the upper end edge of the inner peripheral surface 3a of the inner member 3, and a predetermined pressure in the arrow A direction is applied to the bearing structure 1.

Here, the predetermined pressure is about 1 kgf. In this case, the spherical portion 10a is in contact with the inner peripheral surface 3a of the inner member 3.

By rotating the receiving member 5 in this state, the outer member 4 is rotated without rotating the inner member 3 and the detection by the detector 12 is started.

That is, as shown in the flow chart of FIG. 3, the frequency analyzer 32 determines the predetermined frequency (1 to 15 KHz).
Only through and pick up the acceleration level at certain frequencies (3 KHz and 7 KHz) within this range,
Whether or not these levels are below a predetermined level is determined. If the level is below the predetermined level, a good display is performed, and if the level is above the predetermined level, a defective display is performed.

As shown in FIG. 4, when the horizontal axis is the frequency (frequency) and the vertical axis is the sensitivity, the displacement of vibration becomes sensitive as the frequency increases, as shown by the chain double-dashed line. Becomes smaller, the vibration velocity has a constant sensitivity as indicated by the one-dot chain line, and the vibration acceleration has a higher sensitivity as the frequency increases.

Therefore, if this apparatus is used, the discrimination is made based on the vibration acceleration, so that a small bearing structure having a large natural frequency can be inspected with high accuracy.

Further, the rotating mechanism 6 includes a holding table 8 with a cushioning material 7.
Therefore, the bearing structure 1 can be inspected more reliably.

Next, FIG. 5 shows a cross-sectional view of the essential parts of another embodiment, in which the inner member 3 is rotated without rotating the outer member 4 for inspection.

That is, the receiving member 5 in this case has the small diameter portion 40 at the tip, and the small diameter portion 40 is fitted into the hole portion of the inner member 3. At this time, the outer peripheral surface 40a of the small diameter portion 40 and the inner peripheral surface 3a of the inner member 3 come into close contact with each other.

The presser 10 is provided with a disk body 42 having a hanging wall 41 on the outer peripheral edge thereof, and a connecting body 43 for connecting the disk body 42 and the detector 12 to each other. Press against.

That is, a circumferential notch 44 is provided on the inner diameter side of the lower surface of the hanging wall 41, and the upper outer peripheral edge of the outer member 4 is fitted into the notch 44.

Therefore, the receiving member 5 is rotated by the rotation driving means 9.
When is rotated about its axis as indicated by the arrow, the inner member 3 is similarly rotated, and the outer member 4 is pressed in the direction of the arrow A by the pressing element 10 and does not rotate.

As a result, the vibration of the bearing structure 1 can be measured, as in the above-mentioned embodiment.

Next, in FIG. 6, the bearing structure 1 is a bearing unit, the inner member 3 is a shaft, and the outer member 4 is a cylinder that is fitted onto the shaft.

Then, the outer member 4 is fitted into the fitting recess 16 of the receiving member 5, so that the bearing structure 1 is fitted into the receiving member 5.
Is held by the inner member 3 of the pusher 10 at its tip spherical portion 10a.
Of the screw hole 46 provided on the one end surface 45 of the
In this state, a predetermined pressure is applied to the bearing structure 1 by the pressing element 10.

Therefore, also in this case, similarly, highly accurate vibration measurement can be performed.

The present invention is not limited to the above-mentioned embodiments, and the design can be freely changed without departing from the gist of the present invention. For example, even if the frequency range passed by the frequency analyzer 32 is changed, The frequency to be discriminated can be freely changed within the passed frequency range.

Also, as the pressurizing means 11, it is possible to apply a predetermined pressure to the inner member 3 or the outer member 4 of the bearing structure 1 by pressing the pusher 10 connected to the detector 12. As long as the cylinder 28 and the guide rod 31 are provided, a screw rod and a nut member screwed to the screw rod may be provided instead of the cylinder 28 and the guide rod 31.

[0054]

Since the present invention is configured as described above, it has the following effects.

The small bearing structure 1 having a high natural frequency is inspected for the presence or absence of scratches on balls and the like, the inspection for dust noise (sound generated when foreign matter is mixed), and the NRRO inspection.
It can be performed with high accuracy.

Moreover, since the holding table 8 is provided with the cushioning material 7, the above-mentioned inspection becomes stable.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part.

FIG. 3 is a flow chart diagram.

FIG. 4 is a graph showing the relationship between the frequency of acceleration / velocity / displacement and sensitivity.

FIG. 5 is an enlarged cross-sectional view of a main part of another embodiment.

FIG. 6 is an enlarged cross-sectional view of a main part of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing structure 2 Ball 3 Inner member 4 Outer member 5 Receiving member 6 Rotating mechanism 7 Cushioning material 8 Holding table 9 Rotating drive means 10 Presser 11 Pressurizing means 12 Detector 13 Discriminating means

Claims (1)

[Claims] 1. A plurality of balls 2, ... Arranged along the circumferential direction are interposed between the inner and outer members 3,4 to form the inner and outer members 3,4.
Is a vibration measuring device for measuring vibration of a bearing structure 1 which is rotatable relative to each other, and includes a rotating mechanism 6 having a rotatable receiving member 5 for receiving an inner member 3 or an outer member 4, and the rotating mechanism 6 A holding table 8 with a cushioning material 7 for holding the inner member 3 or the outer member 4 by rotating the receiving member 5 of the rotating mechanism 6.
A rotation driving means 9 for rotating the pressing member, a pressing member 10 for pressing the outer member 4 or the inner member 3 which is not rotating, and a pressing member for pressing the pressing member 10 to apply a predetermined pressure to the bearing structure 1. 11
And a detector 12 that is connected to the presser 10 to detect the vibration acceleration, and a determination unit 13 that determines whether or not the detected acceleration is below a predetermined level. apparatus.