JPH0712686A - Fatigue tester for rolling bearing - Google Patents

Abstract

PURPOSE:To precisely detect fatigue degree of an element to be tested before end of a life by pressing an AE(acoustic emission) sensor mounted at a sample bearer to the element to be tested fixed to a bearer, and detecting the AE generated from the element to. be tested. CONSTITUTION:First, a hydraulic cylinder 5 is operated with a low pressure, a piston rod 2 is extended, an outer race 1 is brought into contact with a sphere 15, and the race 1 is clamped by a bolt 8, and the race 1, an inner race 12 are aligned with the sphere 15. Then, a rotary spindle 3 is rotated at a predetermined testing number of revolutions, the cylinder 5 is operated at a high pressure, and a sample bearer 2 is pressed from below through a rod 21 and a sphere 22. The bearing sphere 15 travels on the race 1 at a high speed while pressing the race 1 of an element to be tested. An AE signal generated due to cause such as a fine damage, etc., generated at the race 1 is detected by an AE sensor 6, and output to an analyzer 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing fatigue tester for performing a fatigue test on a test object by sandwiching the test object between a rotating spindle and a sample table.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, a fatigue tester for a rolling bearing of this type has a device in which a test object 30 fixed to a sample table 25 is extended by a piston rod 23 so that a ball 55 and a rotation can be obtained. The ring 52 is pressed against the rotary spindle 26.

The fatigue tester is equipped with the rotary spindle 2
6 around the axis to rotate the ball 55 and the DUT 3
Rolling contact with 0. When the rolling contact causes peeling or the like of the ball 55 or the DUT 30 to increase the vibration resistance, the vibration pickup attached to the testing machine detects the vibration increase and the rotation of the rotary spindle 26 is stopped. .

[0004]

However, in the conventional rolling bearing fatigue testing machine described above, unless the ball 55 or the test object 30 is peeled off to increase the vibration resistance, the test object 30 is abnormal ( (Fatigue) cannot be detected.

Therefore, an object of the present invention is to provide a fatigue testing machine for rolling bearings, which can detect fatigue of a test object before a defect such as peeling occurs and can accurately detect fatigue of the test object. To do.

[0006]

In order to achieve the above object, a rolling bearing fatigue testing machine of the present invention comprises a sample stage on which an object to be tested is fixed and an opposite side of the sample table with respect to the object to be tested. The rotary spindle located, the load applying member for pressing the sample stage toward the rotary spindle to apply a load to the DUT, and the AE attached to the sample stage so as to contact the DUT. It is characterized by comprising a sensor and a fatigue detecting means for detecting a fatigue state of the device under test based on a signal from the AE sensor.

[0007]

According to the above structure, the load applying member presses the sample table toward the rotary spindle to apply a load to the DUT. Then, the rotary spindle rotates around the axis. As a result, the device under test is rotated while being applied with a thrust load.

During this fatigue test, the AE sensor mounted on the sample table so as to come into contact with the test object detects the AE (acoustic emission) generated by the test object and generates an AE signal. The fatigue detecting means receives the AE signal from the AE sensor,
Based on this AE signal, the fatigue state of the test object is detected.

As described above, according to the present invention, the fatigue of the test object is detected based on the AE signal from the AE sensor that detects the AE generated by the test object. The degree of fatigue of the test object can be accurately detected by detecting the AE that occurs due to a minute scratch that occurs before the end.

[0010]

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

FIG. 1 shows an embodiment of a rolling bearing fatigue tester of the present invention. In this embodiment, a cylindrical sample stand 2 to which an outer ring 1 of a rolling bearing as a test object is fixed,
It has a hydraulic cylinder 5 for pressing the sample table 2 toward the rotary spindle 3 and an AE sensor 6 attached to the sample table 2 so as to contact the outer ring 1.

An outer ring fixing bolt 8 is attached to a screw hole 7a formed in the outer peripheral wall 7 of the sample table 2. By tightening the bolt 8, the axial center position of the outer ring 1 is fixed. ing. The inside of the outer peripheral wall 7 is filled with a lubricating oil 24 that lubricates the rolling bearing.

The AE sensor 6 is inserted into a through hole 10 formed in the sample table 2 through an O-ring 11, and is supported from below by a support plate 17 fixed to the bottom of the sample table 2. There is.

The output signal of the AE sensor 6 is input to the signal analysis device 18.

The inner ring 12 of the rolling bearing is press-fitted into the tip end step portion 13 of the rotary spindle 3 via an annular jig 14 for removal. The inner ring 12 can be easily removed from the rotary spindle 3 using the removing jig 14. In addition, the ball 15 of the rolling bearing
The retainer 16 is engaged with the inner ring 12. Therefore, when the sample table 2 is lowered from the position shown in FIG. 1, the balls 15 and the retainer 16 are not lowered, and remain together with the inner ring 12 fixed to the rotary spindle 3.

A conical recess 20a is formed on the bottom surface of the central shaft portion 20 of the sample table 2. A sphere 22 is fitted in the conical recess 20a. On the other hand, a conical recess 21a facing the conical recess 20a is formed on the upper surface of the piston rod 21 of the hydraulic cylinder 5. The sample table 2 is connected to the hydraulic cylinder 5 via the sphere 22.
The outer ring 1 is supported by the piston rod 21 of
The sample table 2 can be tilted autonomously so as to uniformly press.

In the rolling bearing fatigue testing machine having the above construction, first, the piston rod 21 is in a contracted state. At this time, the outer ring 1 placed on the sample table 2 is
The inner ring 12 and a ball 15 engaged with the inner ring 12
And the retainer 16 are separated from each other. At this time, the outer ring fixing bolt 8 of the sample table 2 is loosened, and the outer ring 1
Is movable in the radial direction.

Next, the hydraulic cylinder 5 is operated at a low pressure to extend the piston rod 21. Then, the outer ring 1 contacts the ball 15. At this time, when the rotary spindle 3 is lightly rotated, the outer ring 1 is moved in the radial direction so that the center of the ring of the balls 15 arranged in a ring and the axis of the outer ring 1 are aligned. Thus, the radial position of the outer ring 1 is adjusted to an appropriate position. Then, the outer race 1 is fastened to the proper position by tightening the outer race 1 with the outer race fixing bolt 8. In this way, the outer ring 1 and the inner ring 12 and the ball 15 can be easily and reliably aligned.

Next, the rotary spindle 3 is rotated at a predetermined test rotation speed, and the hydraulic cylinder 5 is operated at a high pressure so that the piston rod 21 presses the sample table 2 from below through the ball 22. Thereby, the fatigue test of the rolling bearing is started, and the ball 15 of the rolling bearing is
While pressing the outer ring 1 as the test object, it travels on the outer ring 1 at high speed.

On the other hand, the AE sensor 6 detects an AE generated by the outer ring 1 due to a cause such as a minute scratch generated on the outer ring 1 during the fatigue test, and outputs an AE signal to the signal analysis device 18. To do. The signal analyzer 18 analyzes the AE signal to detect the degree of fatigue of the outer ring 1.

Thus, according to the above embodiment, the outer ring 1
Before the outer ring 1 becomes unusable due to excessive frictional resistance between the outer ring 1 and the ball 15, the outer ring 1
It is possible to detect minute scratches that occur in the. Therefore, according to this embodiment, it is possible to accurately detect the degree of fatigue of the outer ring 1 before the end of its life.

In the above embodiment, the AE sensor 6 is inserted into the through hole 10 from the lower side of the outer ring 1 placed on the sample table 2 through the O-ring 11, and the support plate 17 is attached to the bottom surface of the AE sensor 6. The AE sensor 6 by immersing the AE sensor 6 in the lubricating oil 24 by bolting it to the sample table 2 by applying it to the outer ring 1
Can be directly contacted with. Therefore, according to this embodiment, the AE sensor 6 can accurately measure the AE generated by the outer ring 1 without invading the lubricating oil 24.

Further, in the above embodiment, the outer ring fixing bolt 8 is loosened to be separated from the outer ring 1, and then the ball 15 and the outer ring 1 are slid around the shaft while engaging with each other. The axial center position can be adjusted by moving 1 in the radial direction by a small distance. After that, the outer ring fixing bolt 8 is tightened and brought into contact with the outer ring 1, whereby the outer ring 1
Can be fixed in a proper position. That is, according to this embodiment, the outer ring 1 can be fixed while being aligned.

[0024]

As is clear from the above, in the rolling bearing fatigue testing machine of the present invention, the load applying member presses the sample table, to which the test object is fixed, toward the rotary spindle, while the test object is tested. An AE sensor attached to the sample table so as to contact the AE detects the AE generated by the DUT.

Therefore, according to the present invention, the AE generated by the test object can be detected to detect the minute scratches generated on the test object, and the fatigue level of the test object before the end of its life can be accurately measured. Can be detected.

[Brief description of drawings]

FIG. 1 is a half sectional view of an embodiment of a rolling bearing fatigue testing machine of the present invention.

FIG. 2 is a sectional view of a conventional rolling bearing fatigue testing machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer ring, 2 ... Sample stage, 3 ... Rotating spindle, 5 ... Hydraulic cylinder, 6 ... AE sensor, 7 ... Outer peripheral wall, 7a ... Screw hole, 8 ... Outer ring fixing bolt, 12 ... Inner ring, 13 ... Tip step part, 14 ... Removal jig, 15 ... Ball, 16 ... Retainer,
24 ... Lubricating oil.

Claims (1)

[Claims] 1. A sample stage to which a DUT is fixed, a rotary spindle located on the side opposite to the sample stage with respect to the DUT, and the test stage by pressing the sample stage toward the rotary spindle. A load applying member that applies a load to the body, an AE sensor attached to the sample table so as to come into contact with the test object, and a fatigue state of the test object based on a signal from the AE sensor A fatigue testing machine for rolling bearings, comprising: