JP3215547B2 - Rolling bearing fatigue tester - Google Patents

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 stage.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, a fatigue tester for a rolling bearing of this type is configured such that a test object 30 fixed to a sample table 25 is extended by a piston rod 23 to thereby form a ball 55 and a rotating member. The rotation spindle 26 is pressed through the ring 52.

[0003] The above-mentioned fatigue tester is composed of the above-mentioned rotary spindle 2
6 is rotated about an axis, and the ball 55 and the DUT 3 are rotated.
0 and rolling contact. When the rolling contact causes the ball 55 or the test object 30 to peel off or the like and the vibration resistance increases, the vibration pickup detected by the vibration pickup attached to the testing machine detects the increase in the vibration, and the rotation of the rotary spindle 26 stops. .

[0004]

However, in the conventional rolling bearing fatigue testing machine, the ball (55) or the test piece (30) is not affected unless the ball (55) or the test piece (30) is peeled off and the vibration resistance is increased. Fatigue) cannot be detected. In particular, when the surface treatment is performed with a thin film, it is extremely difficult to detect an abnormality because the increase in vibration resistance is extremely small when the thin film is peeled.

Accordingly, an object of the present invention is to provide a rolling bearing fatigue testing machine capable of detecting fatigue of a test object before a defect such as peeling occurs, and detecting the fatigue of the test object accurately. Is to do.

[0006]

In order to achieve the above object, a rolling bearing fatigue testing machine according to the present invention comprises: a sample table on which a test object is fixed; and a sample table on a side opposite to the sample table with respect to the test object. A rotating spindle positioned, a load applying member for pressing the sample stage toward the rotating spindle to apply a load to the test object, and an AE attached to the sample stage so as to contact the test object. A sensor, and 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 configuration, the load applying member presses the sample stage toward the rotating spindle to apply a load to the test object. Then, the rotating spindle rotates around the axis. Thus, the test object is rotated while a thrust load is applied.

At the time of the fatigue test, an AE sensor attached to the sample table so as to contact the test object detects an AE (acoustic emission) generated by the test object and generates an AE signal. And the fatigue detecting means receives an AE signal from the AE sensor,
Based on the 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 which detects the AE generated by the test object. AE caused by micro scratches that occur before the end or the thin film is peeled off and its function is deteriorated.
And the fatigue process of the test object can be accurately detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of a rolling bearing fatigue tester according to the present invention. In this embodiment, a cylindrical sample table 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 stage 2 toward the rotary spindle 3 and an AE sensor 6 attached to the sample stage 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 stage 2, and the axial center position of the outer ring 1 is fixed by tightening the bolt 8. ing. The inside of the outer peripheral wall 7 is filled with a lubricating oil 24 for lubricating the rolling bearing.

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

The output signal of the AE sensor 6 is input to a signal analyzer 18.

The inner race 12 of the rolling bearing is press-fitted into a step 13 at the tip of the rotary spindle 3 via an annular removal jig 14. The inner ring 12 can be easily removed from the rotary spindle 3 by using the above-described removal jig 14. In addition, the ball 15 of the rolling bearing is used.
The retainer 16 is engaged with the inner ring 12. Therefore, when the sample stage 2 is lowered from the position shown in FIG. 1, the balls 15 and the retainer 16 do not descend, but remain upward together with the inner ring 12 fixed to the rotary spindle 3.

On the bottom surface of the central shaft portion 20 of the sample stage 2, a conical concave portion 20a is formed. The sphere 22 is fitted into 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 stage 2 is connected to the hydraulic cylinder 5 via the ball 22.
Is supported by the piston rod 21 of the outer ring 1
Can be tilted autonomously so as to press uniformly.

In the rolling bearing fatigue tester having the above-described structure, first, the piston rod 21 is in a contracted state. At this time, the outer ring 1 placed on the sample table 2
The inner ring 12 and the 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 stage 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 race 1 comes into contact with 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 coincide with each other. Then, the radial position of the outer race 1 is adjusted to an appropriate position. Then, the outer ring 1 is tightened with the outer ring fixing bolt 8 to fix the outer ring 1 at the appropriate position. In this manner, the positioning of the outer race 1 with the inner race 12 and the ball 15 can be performed easily and reliably.

Next, the rotary spindle 3 is rotated at a predetermined test rotational speed, and the hydraulic cylinder 5 is operated at a high pressure to press the sample table 2 from below through the ball 22 with the piston rod 21. Thereby, the fatigue test of the rolling bearing is started, and the ball 15 of the rolling bearing is
The vehicle runs on the outer ring 1 at a high speed while pressing the outer ring 1 as a test object.

On the other hand, the AE sensor 6 detects an AE generated by the outer race 1 due to a minute scratch or the like generated on the outer race 1 during the fatigue test, and outputs an AE signal to the signal analyzer 18. I do. The signal analyzer 18 analyzes the AE signal and detects the degree of fatigue of the outer race 1.

As described above, according to the above embodiment, the outer race 1
Before the outer ring 1 becomes unusable because the frictional resistance between the outer ring 1 and the ball 15 becomes excessive, the AE sensor 6 is used to
Can be detected. Therefore, according to this embodiment, it is possible to accurately detect the degree of fatigue of the outer race 1 before the end of its life.

In the above-described embodiment, the AE sensor 6 is inserted into the through hole 10 through the O-ring 11 from below the outer ring 1 placed on the sample table 2, and the support plate 17 is attached to the bottom of the AE sensor 6. AE sensor 6 is immersed in lubricating oil 24 by bolting to
Can be directly abutted. Therefore, according to this embodiment, the AE sensor 6 can accurately measure the AE generated by the outer ring 1 without affecting the lubricating oil 24.

Further, in the above embodiment, the outer ring fixing bolt 8 is loosened so as to be separated from the outer ring 1, and then the ball 15 and the outer ring 1 are slid around the axis while being engaged with each other. 1 can be moved by a small distance in the radial direction to adjust the axial center position. Thereafter, the outer ring fixing bolt 8 is tightened and brought into contact with the outer ring 1 so that the outer ring 1
Can be fixed at an appropriate position. That is, according to this embodiment, the outer ring 1 can be fixed while being centered.

[0024]

As is apparent from the above description, in the fatigue testing machine for a rolling bearing according to the present invention, the load applying member presses the sample stage on which the test object is fixed toward the rotating spindle, while An AE sensor attached to the sample table so as to come into contact with the sample detects the AE generated by the test object.

Therefore, according to the present invention, it is possible to detect the AE generated by the test object, to detect the micro scratches generated in the test object, and to precisely measure the fatigue degree of the test object before the end of its life. Can be detected.

[Brief description of the drawings]

FIG. 1 is a half sectional view of an embodiment of a rolling bearing fatigue tester according to the present invention.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer ring, 2 ... Sample stand, 3 ... Rotary spindle, 5 ... Hydraulic cylinder, 6 ... AE sensor, 7 ... Outer 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)

(57) [Claims] A sample stage on which a device under test is fixed; a rotary spindle positioned on the opposite side of the sample stage with respect to the device under test; A load applying member for applying a load to the body, an AE sensor attached to the sample table so as to abut on the test object, and detecting a fatigue state of the test object based on a signal from the AE sensor. A fatigue tester for rolling bearings, comprising: