RU169375U1 - ROLLING FRICTION MACHINE - Google Patents

Abstract

The utility model relates to mechanical engineering and can be used to test machine parts for wear and rolling friction resistance. The rolling friction machine contains a frame, a housing fixed on it with balls placed therein, a sample and a counter sample made in the form of a cylindrical cone, a loading unit and a rotation sample rotation drive. Between the bed and the housing there is a torque sensor. The outer ring of a ball bearing was used as a sample. The cone angle of the counter-pattern is equal to the double contact angle of the balls with the race of the ball bearing. The technical result is to provide the possibility of free rotation of the balls along the raceway of the ball bearing ring at a given contact angle and to increase the accuracy of measuring the rolling friction moment. 1 ill.

Description

The utility model relates to mechanical engineering and can be used to test machine parts for wear and rolling friction resistance.

A known method and device for defectoscopy of a moving surface during a wear test, in which the parts are pressed against each other and judging by the acoustic vibrations of the probe pressed against the surface to be examined, is judged on the state of this surface (copyright certificate SU No. 407211).

The disadvantage of this device is the great effort required for the test, and the long test time.

A known machine for studying the process of friction of balls inside a ring (copyright certificate SU No. 186183), in which the balls are pressed against the inner surface of the ring under the action of centrifugal force.

The disadvantage of this device is the difficulty of regulating the load and the fact that it is impossible to transfer the combined load to the friction parts.

The closest in technical essence and combination of features to the claimed one is a rolling friction machine containing a frame, a housing fixed to it with balls placed in it, a sample and a counter sample made in the form of a cylindrical cone, a loading unit and a rotation sample rotation drive (copyright certificate SU No. 1174830 ) The device is equipped with a cup mounted in the housing along which the balls roll, a mechanism for clamping balls between the housing cover and the base of the cup, which prevents the free rotation of the balls, the housing is mounted on a bed with limited angular movement, and balls are used as a sample.

The disadvantage of this device is that it does not provide test conditions that are close to the operating conditions of the rolling bearing with free rotation of the balls. Since the balls, based on the bottom of the cup, always experience additional resistance to rotation, the cup does not match the shape of the bearing rings, a device that provides limited angular movement of the housing causes additional resistance to rotation of the housing, which introduces a significant error in the measurement of the friction moment.

The objective of this utility model is to provide test conditions that are close to the conditions of free rolling of balls in a ball bearing while expanding the technological capabilities of the device.

The problem is achieved in that in a rolling friction machine containing a bed, a housing fixed to it with balls placed therein, a sample and a counter sample made in the form of a cylindrical cone, a loading unit and a counter-rotation rotation drive, a torque sensor is placed between the frame and the body, the outer ring of the ball bearing was used as a sample, and the angle of the cone of the counter-pattern is equal to the double angle of contact of the balls with the raceway of the ball bearing.

The technical result is to provide the possibility of free rotation of the balls along the raceway of the ball bearing ring at a given contact angle and to increase the accuracy of measuring the rolling friction moment.

Since the outer ring of the ball bearing is used as the sample, and the cone angle of the counterbores corresponds to the contact angle of the balls with the raceway of the sample, this brings the test conditions closer to the conditions of free rotation of the balls in the ball bearing. The device allows you to investigate the influence of the geometric parameters of the working surface of ball bearing parts, their material, manufacturing technology, the lubricant used, the contact angle and other means on friction and wear and thereby determine the rational conditions for the manufacture and operation of the rolling bearing. This extends the technological capability of the device compared to the prototype. And since the body of the device is installed directly on the torque sensor, this increases the accuracy of the measurement, since extraneous factors do not affect the torque.

The essence of the utility model is illustrated in the drawing, which shows a General view of the proposed device.

In the drawing are indicated:

1 - test sample;

2 - case;

3 - intermediate sleeve;

4 - separator;

5 - balls;

6 - counterbody;

7 - pressure shaft;

8 - cover;

9 - torque sensor;

10 - base.

The test sample 1, which is the outer ring of the ball bearing, is installed in the housing 2 through the intermediate sleeve 3. Inside the test sample 1 in the cage 4 are balls 5. The diameter of the balls 5 is equal to the diameter of the balls in the ball bearing. Between the balls 5, a conical-shaped counterbody 6 is mounted, connected by means of a face key connection to the pressure shaft 7. The pressure shaft 7 is under the action of the axial force P created by the loading mechanism (not shown). On top of the housing 2, a lid 8 is fixed with a central hole for inputting the pressure shaft 7. The lid 8 clamps the test piece 1 at the end, preventing its rotation.

The whole structure is placed on the torque sensor 9, mounted on the base 10. The angle of the cone of the counterbody 6 is equal to the required double contact angle of the balls 5 with the race of ball bearing. In the cavity of the housing 2, made in the form of a glass, lubricating coolant of various compositions can be poured, and the test sample 1 can be made of various materials using various technologies.

The operation of the device is as follows. The pressure shaft 7 is rotated at a frequency n, as a result of which the counterbody 6 is rotated. Due to the frictional forces with the counterbody 6 loaded with force P, balls 5 are rotated, which make a break-in movement along the raceway of the ball bearing. The rolling friction moment arising between the balls 5 and the test piece 1 is measured by a torque sensor 9 fixed to the base 10. After a predetermined break-in time, the rotation of the pressure shaft 7 is stopped, the pressure shaft 7 is retracted in the vertical direction, the cover 8 is removed from the housing 2, and from it the cavities are removed counterbody 6, balls 5 with a separator 4 and the test sample 1. Measured wear of the working surfaces of the sample 1 and counterbody 6, the magnitude of which and the magnitude of the rolling friction moment, measured during the test Determined by the efficiency of design and technological activities. If samples of various sizes are tested, then sleeve 3 also changes with sample 1.

Using the proposed design of the rolling friction machine in comparison with the known allows: to study the influence of the geometric parameters of the working surface of the parts of ball bearings, their material, manufacturing technology, the applied lubricant, contact angle and other means on friction and wear and thereby determine the rational conditions for the manufacture and operation of the bearing rolling. This extends the technological capability of the device compared to the prototype. In addition, the accuracy of measuring the rolling friction moment between the balls 5 and the sample 1 is improved, since other elements of the device do not affect this indicator.

Example. A prototype of the inventive device was used to determine the effect of grease on the moment of rolling friction and wear of the working surfaces of a ball bearing 36308. Bearing dimensions: inner diameter 40 mm, outer diameter 90 mm and height 23 mm. The diameter of the balls in the ball bearing is 15 mm, the number of balls is 12. The nominal contact angle in the bearing is β = 12 °.

As a sample, an outer bearing ring with a radius of the raceway profile rg = 7.72 mm was used. A study was made of the influence of various types of lubricants at the time of rolling friction and wear: TsIATIM GOST 8551-74, Litol 24 GOST 21150-87 and VNII NP-282 GOST 24926-81.

For the study, the average operating mode of the bearing was used: axial load P = 6000 N, rotation speed n = 3000 rpm, test time τ = 8 hours. The tests were carried out with a full set of balls, since in this case the wear manifests itself especially clearly. The counterbody was made of the same material from which the bearing ring is made - ШХ15 steel. The cone angle of the sample was taken equal to α = 2β = 24 °. Depreciation was measured by profiling the generatrix of the counterbody on a profilometer.

The test results are shown in table 1.

As you can see, TIATIM grease provides significantly less rolling friction and less wear than other greases.

Thus, the proposed device allows in a short time to study the moment of rolling friction and wear under conditions close to the operating conditions of the rolling bearing.

Claims (1)

A rolling friction machine comprising a bed, a housing fixed on it with balls placed therein, a sample and a counter sample made in the form of a cylindrical cone, a loading unit and a counter sample rotation drive, characterized in that a torque sensor is placed between the frame and the body as a sample the outer ring of the ball bearing is used, and the angle of the cone of the counter-pattern is equal to the double angle of contact of the balls with the race of ball bearing.

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