JP3130986B2 - Vibration measuring device - Google Patents

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 a circumferential direction is interposed between inner and outer members so that the inner and outer members are rotatable relative to each other, specifically, for example, In the case of manufacturing a ball bearing having an inner and outer ring and a ball interposed between the inner and outer rings, inspection for the presence of damage to the ball and the like, inspection for dust noise (sound generated by the incorporation of foreign matter) defects , And NRRO.

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

[0004]

However, a small bearing has a high natural frequency, and the higher the frequency, the lower the sensitivity is, which makes it impossible to perform an accurate inspection.

Accordingly, 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 comprises a plurality of balls disposed along a circumferential direction 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, comprising: a rotation mechanism having a rotatable receiving member for receiving an inner member or an outer member; and a cushioning material for holding the rotation mechanism. It said a holder with a rotary drive means for rotating the receiving member to rotate said inner member or outer member of the rotating mechanism, a pushing element for pressing the outer member or the inner member does not rotate, the pressing indenter Coincides with the rotation axis of the bearing structure
Pressing means for applying a predetermined pressure to the bearing structure by pressing in a direction, a detector connected to the pressing element for detecting a vibration acceleration, and determining whether the detected acceleration is equal to or less than a predetermined level. Discriminating means for discriminating.

[0007]

The inner member or the outer member is rotated by a rotating mechanism, and a pressing element is pressed on the non-rotating outer member or the inner member via a pressing means to apply a predetermined pressure to the bearing structure. Then, the vibration acceleration can be detected by the detector.

Then, it is judged by the judging means whether or not the acceleration level is lower than a predetermined level. If the acceleration level is lower than the predetermined level, it is judged as good, and if it is higher than the predetermined level, it is judged as defective.

By the way, generally, the vibration velocity is a displacement amount per unit time, and V (t) = A · 2πfcos2π
ft, where the vibration acceleration is a variable in 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 amplitude of the velocity is 2πfA, the amplitude of the acceleration is (2πf) ² A, and the amplitude of the acceleration is
Since the frequency increases as the frequency increases, if the inspection is performed with acceleration as in the present invention, the sensitivity increases and the quality can be determined reliably.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 is an overall simplified view of a vibration measuring apparatus according to the present invention, which measures 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 along the circumferential direction interposed between the inner and outer members 3 and 4. Reference numeral 4 denotes a ball bearing in which the inner member 3 is an inner race and the outer member 4 is an outer race.

[0014] Then, 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 rotational drive for rotating the receiving member 5 of the rotating mechanism 6 Means 9 and the non-rotating outer member 4 or inner member 3
Presser 10 which presses against the bearing , and presses the presser 10
A pressurizing means 11 for applying a predetermined pressure to the structure 1 by pressing in a direction coinciding with the axis of rotation; a detector 12 connected to the presser 10 for detecting vibration acceleration; A determining means 13 for determining whether or not the acceleration is equal to or lower than a predetermined level;

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

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

That is, as shown in FIG. 2, the outer member 4 is fitted into the fitting recess 16, the inner member 3 is not in contact with the receiving member 5, and the bearing structure 1 is 5

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

The transmission mechanism 19 includes a pulley 20 attached to an output shaft of a driving motor 18 and a main body 14 of the rotation mechanism 6.
Pulley 21 attached to and coupled to receiving member 5
And a belt 22 wound around the pulleys 20, 21.

Accordingly, when the driving motor 18 is driven, the pulley 20 rotates, and this rotation rotates the pulley 21 via the belt 22, whereby the receiving member 5 rotates about its axis.

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

As shown in FIG. 2, the pressing element 10 comprises a tip spherical portion 10a and a main portion 10c connected to the spherical portion 10a via a tapered portion 10b.
, A detector 12 is provided in series.

That is, when the taper 10b is in contact with the upper end edge of the inner peripheral surface 3a of the inner member 3, the ball 10a is inserted into the inner member 3 and the bearing structure 1 Press in the direction. That is, a direction that coincides with the rotation axis of the bearing structure 1.
The pressing element 10 presses the bearing structure 1.

Thus, the detector 12 uses a piezoelectric transducer, and detects the acceleration of the vibration of the bearing structure 1 received through the presser 10.

The pressing means 11 includes a shaft 25 erected on the holding table 8, a block 26 attached to the shaft 25, and a guide frame 27 attached to the block 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 projected from the slide table 29
And the arm 30 holds the detector 12.

That is, the positioning of the presser 10 is roughly performed by the positioning of the block body 26, and the cylinder 28 is moved up and down along the guide rod 31 of the guide frame 27, thereby positioning the presser 10 with high accuracy. Do.

The block 26 is positioned by using the shaft 25 as a threaded rod, the slide body 26 as a nut member screwed to the threaded rod, and rotating the shaft 25 about its axis to move the block 26. It is also preferable to carry out the operation by moving it up and down.

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

The detector 12 is connected to a frequency analyzer 32. This 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 a frequency of 1 KHz or more,
The low-pass filter 34 passes a signal of 15 KHz or less.

Therefore, those having a frequency in the range of 1 KHz to 15 KHz pass.

Then, 1KH that has passed through the frequency analyzer 32
Within the range of z to 15 KHz, the determination means 13 determines whether the acceleration level at a certain frequency is smaller than a reference (predetermined) level. In the embodiment, 3KHz and 7KHz
Is determined.

That is, the level of the frequency to be determined by the reference setting device 35 is set.
The reference value is input to the controller and the reference value is compared with the detected acceleration level.

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

Therefore, as the display means 36, a display light which is different in color between good and bad lights up, a display light turns on only in the case of badness, and characters "good" and "bad" are displayed. There are various things such as those performed. Further, in the case of a failure, it is also preferable to generate a sound indicating that the failure has occurred.

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

First, as shown in FIG. 2, the bearing structure 1 is
The pressing member 10 is lowered through the pressing means 11 while being fitted into the fitting recess 16 of the receiving member 5, and the spherical portion of the pressing member 10 is
10a is inserted into the inner member 3, and the tapered portion 10b is pressed against the upper end edge of the inner peripheral surface 3a of the inner member 3, so that the bearing structure 1 is directed in the direction of arrow A (the direction coincident with the rotation axis). Is applied.

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

Then, 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, a predetermined frequency (1 to 15 KHz) is
Only, and picks up acceleration levels at certain frequencies (3 KHz and 7 KHz) within this range,
It is determined whether or not these levels are lower than a predetermined level. If the level is lower than the predetermined level, good display is performed. If the level is higher than the predetermined level, defective display is performed.

As shown in FIG. 4, if the horizontal axis is the frequency (frequency) and the vertical axis is the sensitivity, the displacement of the vibration becomes higher as the frequency becomes higher, as indicated by the two-dot chain line. Becomes smaller, the sensitivity is constant as shown by the dashed line, and the sensitivity of the vibration acceleration increases as the frequency increases.

Therefore, if this device is used, the determination is made based on the vibration acceleration, and therefore, a small bearing structure having a large natural frequency can be inspected with high accuracy.

The rotating mechanism 6 includes a holding table 8 with a cushioning material 7.
, The inspection of the bearing structure 1 can be made more reliable.

Next, FIG. 5 is a sectional view of a main part of another embodiment. In this case, the inspection is performed by rotating the inner member 3 without rotating the outer member 4.

That is, the receiving member 5 in this case has a small-diameter portion 40 at the tip, and the small-diameter portion 40 is fitted into the hole 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 pressing element 10 includes a disk 42 having a hanging wall 41 on the outer peripheral edge, and a connecting body 43 connecting the disk 42 and the detector 12. 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.
Is rotated about its axis as shown by the arrow, the inner member 3 is similarly rotated, and the outer member 4 is moved by the pressing element 10 in the direction of the arrow A.
(In the direction coinciding with the rotation axis of the bearing structure 1) and does not rotate.

Thus, the vibration of the bearing structure 1 can be measured as in the above-described embodiment.

FIG. 6 shows a bearing structure 1 as a bearing unit, in which an inner member 3 is a shaft, and an outer member 4 is a cylindrical body fitted to the shaft.

Then, the outer member 4 is fitted into the fitting recess 16 of the receiving member 5, and the bearing structure 1 is
The pressing element 10 has a spherical end portion 10a at the inner member 3
Into the open end of the screw hole 46 provided on one end surface 45 of the
In this state, the rotation axis of the bearing structure 1 by the presser 10 is
A predetermined pressure is applied in the same direction .

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

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

The pressing means 11 can also apply a predetermined pressure to the inner member 3 or the outer member 4 of the bearing structure 1 by pressing the pressing element 10 connected to the detector 12. As long as it has only to be provided, instead of the cylinder 28 and the guide rod 31, a screw rod and a nut member screwed to the screw rod may be provided.

[0054]

Since the present invention is configured as described above, the following effects can be obtained.

For the small bearing structure 1 having a high natural frequency, an inspection for the presence of scratches such as balls, an inspection for dust noise (sound generated by the inclusion of foreign matter), and an NRRO inspection are performed.
It can be performed with high accuracy.

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

[Brief description of the 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 flowchart.

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

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

FIG. 6 is an enlarged 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 Buffer material 8 Holder 9 Rotation driving means 10 Presser 11 Pressurizing means 12 Detector 13 Discriminating means

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01H 17/00 G01H 11/08 G01M 13/04

Claims (1)

(57) [Claims] A plurality of balls (2) arranged along a circumferential direction are interposed between the inner and outer members (3, 4).
1. A vibration measuring device for measuring vibration of a bearing structure 1 which is rotatable with respect to each other, comprising: a rotating mechanism 6 having a rotatable receiving member 5 for receiving an inner member 3 or an outer member 4; The holding member 8 with the cushioning member 7 for holding the inner member 3 or the outer member 4 by rotating the receiving member 5 of the rotating mechanism 6
Upper and rotary drive means 9 for rotating, a pushing element 10 for pressing the outer member 4 or the inner member 3 not rotating, the pressing indenter 10
Pressing means 11 for applying a predetermined pressure to the bearing structure 1 by pressing in a direction coinciding with the rotation axis of the bearing structure 1, and a detector connected to the pressing element 10 for detecting vibration acceleration 12
And a determining means 13 for determining whether the detected acceleration is equal to or lower than a predetermined level.