RU2280243C1 - Bench for testing bearings - Google Patents

Abstract

FIELD: testing of machine parts.

SUBSTANCE: bench comprises shaft with is provided with driving pulse turbine and is mounted in the housing provided with passages for supplying fluid to the turbine wheel and discharging it from the turbine and bearing to be tested provided with the coating to be tested. The bearing is mounted in the race mounted on the shaft of the pulse turbine and on flexible members. The bench is provided with loading device, temperature sensor, and pickup for measuring torque. The reference bearing is set in the race that is suspended inside the housing by means of flexible members. The driving pulse turbine is mounted on the shaft in its central part. The shaft is set on two bearing that receive the reference and tested bearings symmetrically to the pulse turbine. The loading device is connected to the bottom section of the races of the reference and tested bearings to provide the same load on both of the bearings. The separating heat screen is interposed between the turbine and tested bearing. The reference bearing may be additionally provided with heater and temperature sensor, and it may be provided with a tested coating. The structures of the tested and reference bearing may be the same, or different.

EFFECT: enhanced reliability and simplified structure.

4 cl, 3 dwg

Description

The invention relates to the field of research of the operability of coatings for friction pairs in rotation nodes, for example, pairs: a rotating shaft and a fixed flap element of a gas-dynamic bearing or a rotating shaft and a fixed sleeve, etc.

The invention allows us to determine the comparative performance of the test coatings in a friction pair of a gas bearing, for example, in a gas-dynamic flap bearing - between the shaft and the flap at different operating temperatures and loads with respect to the "standard" known coating under standard conditions, for example, at 15 ° C.

There is a well-known stand given in the article “Some Composite Bearing and Seal Materials for Gas Turbine Arpplications - A Review. Sliney. E. Transections of the ASME, v.112 oct., Pp. 486-488, 1990 ”, comprising a rotating disk and a fixed finger that form a friction pair, a heating element, an electric feeder, and a universal joint.

The disadvantage of this stand is that the anti-wear properties of coatings in a friction pair are studied on samples that have simple shapes that do not match the configuration of a friction pair of real structures of a thin flap element of a gas-dynamic bearing, which undergoes mechanical and thermal deformations during operation. Since the friction surface has a simple shape, it is impossible to recalculate the results obtained on the actual operating conditions of the bearing in turbomachines during dynamic processes occurring in transitional modes of their start-stop.

A well-known stand adopted for the prototype described in the article “Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinary” by C. Della Corte, V. Lukashevicz, MJWalco, H. Heshmat, NASA / TM-2000-209187 / REV1, pp.1, 3, 10, 2000 ”, comprising a test gas bearing, a pulsed air turbine, a drive shaft mounted on oil-lubricated ball bearings, a heater, a loading device, a suspension system and a torque measuring system.

The stand allows you to test the coating directly in the design of the bearing during the deformation of the elements, which takes place in the real conditions of its operation.

The disadvantages of this stand are:

- only one bearing is tested;

- recalculation of the test results is required to compare with the test results of other friction pairs;

- the structural complexity of the stand, consisting in the need to use an additional cantilever suspension system of the turbine rotor on ball bearings and a system for lubricating them with oil.

The objective of the present invention is to increase the reliability of the tests of bearings with various coatings, simplifying the design of the test bench for testing bearings of various shapes and sizes.

The technical result is achieved on a test bench for bearings in simulated operating conditions, containing a shaft with a pulse drive turbine, which is installed in a housing with channels for supplying a working fluid to the turbine wheel and withdrawing it from the turbine, a test bearing with a test coating applied to it, installed in the cage, located on the shaft of the pulse turbine and equipped with a heater, the cage of the test bearing is suspended inside the housing on elastic elements, in addition, the stand is equipped with load a device, a temperature sensor and a torque measurement sensor, and a control bearing mounted in a cage, which is suspended inside the housing on elastic elements, is introduced into the stand, while the drive pulse turbine is located on the shaft in its middle part, which is mounted on two bearings, inside of which are symmetrically in relation to the impulse turbine, the control and test bearings are located, and the load device is connected to the bottom of the cages of the test and control bearings with the possibility of baking the same load on both bearings, and between the turbine and the test bearing is situated separating the heat shield.

Also, the control bearing can be additionally equipped with a heater and a temperature sensor.

A test coating may also be applied to the test bearing.

Also, the designs of the test and control bearings may be the same or different.

The essence of the invention lies in the fact that the drive pulse turbine is mounted on the shaft in its middle part and the test and control bearings are located symmetrically with respect to the pulse turbine (in the particular case of the same design and geometry). The stand is equipped with a loading device, which is installed so that the loads on the test and control bearings are the same, and a torque meter. The test bearing is mounted in a cage, which is suspended inside the housing on elastic elements, and is equipped with a heater to ensure its required thermal regime. Status monitoring is carried out using a temperature sensor, such as a thermocouple.

The technical result of using this test bench for bearing tests under simulated operating conditions is the possibility of simultaneous comparative tests, for example, gas-dynamic bearings with different coatings under simulated operating temperature conditions in the support of a gas turbine engine, for example, ~ 500-600 ° C and “standard, normalized” conditions at t = 15 ° С, and simplification of the stand design, since an oil lubrication system is not required.

The technical result is achieved by the introduction of new elements. These include a control bearing of the same design as the test bearing, they are symmetrically located with respect to the drive pulse turbine. This eliminates the need to install a drive impulse turbine on an additional support with oil-lubricated ball bearings, as shown in the prototype.

The test bench for bearings in simulated operating conditions includes a housing with a shaft and a pulse drive turbine located in its middle part. The shaft is mounted on two bearings, inside of which, for example, two gas bearings are housed in cages of the same design and size. On the friction surface of one of the bearings, for example a test bearing, test coatings are applied. Another bearing, control, has a "standard" coating. The cage of the test bearing with the test coating is equipped with a heater that heats the test bearing to a simulated operating temperature. The stand is equipped with a loading system (load device) of both bearings with the same adjustable working load. The test and control bearings are installed inside the cages on the elastic elements. The test bearing is separated from the drive pulse turbine by a heat shield.

The essence of the invention is illustrated by drawings.

Figure 1 shows a diagram of a longitudinal section of the inventive stand for testing bearings in simulated operating conditions.

Figure 2 shows a cross section aa of the stand of figure 1.

Figure 3 shows a section bB of the stand of figure 1.

The test bench for bearings under simulated operating conditions (see Fig. 1) contains a shaft 1 with a pulse drive turbine 2, a test bearing 3 and a control bearing 4. A test coating (not shown) is applied to the test bearing 3. The test bearing 3 is equipped with a heater 5. The impulse drive turbine 2 is installed on the shaft 1, the test and control bearings 3 and 4 are placed in the housing 6 and installed in the cage 16. A cage 16 of each bearing 3 and 4 is mounted inside the housing 6 on the elastic elements 8. The shaft 1 is equipped with a torque measuring sensor 9. A load device 10 is connected to the bottom of the cage 16 of both bearings 3 and 4. The cage 16 of the test bearing 3 is provided with a temperature sensor 11. A test coating is applied to the test bearing 3. In the housing 6 there is a channel 12 (see FIG. 2) for supplying the working fluid to the turbine wheel 2 and a channel 13 for the working fluid to exit the turbine 2. The housing 6 of the test bearing 3 is separated from the turbine 2 by a heat shield 14. The working fluid, for example, a compressed one air is supplied through the channel 12 to the wheel of the turbine 2 in a pulsed mode in an amount and with a frequency that accelerates and stops the wheel of the drive pulse turbine 2 from the run-out speed to the speed of "ascent" of the shaft 1, in which a carrier gas film is formed in the test bearing 3 and dry tr disappears test in bearing 3 and dry friction disappears in the test pair of coatings.

The stand for testing bearings in simulated operating conditions is as follows.

On the shaft 1 of the turbine 2 is installed, for example, gas bearings 3 and 4, respectively, the test and control. Using the load device 10, the required load on both bearings 3 and 4 is set. Due to the symmetrical design of the load, both bearings 3 and 4 are identical. The heater 5 is turned on and the required thermal state of the parts of the test bearing 3 is set, controlled by the temperature sensor 11. Then, compressed air is supplied to the drive pulse turbine 2. When the drive pulse turbine 2 rotates, dry friction occurs in the contact pair, for example, the test bearing 3, which leads wear of the test coating at the point of contact. As the rotational speed of the drive impulse turbine 2 increases, the lifting force increases in the wedge air gap between the lobe 15 (Fig. 3) of the test bearing 3 and the shaft 1. When the lifting force reaches a value equal to the applied load by the device 10, the shaft 1 "pops up", those. “ascent speeds” are achieved and, while maintaining or further increasing the rotational speed, the wear of the coating in the contact pair ceases. When you turn off the supply of the working fluid to the drive pulse turbine 2, its rotation frequency decreases, the air wedge disappears and dry friction occurs again in the contact pair. Tests of the test bearing 3 with the test coating according to such a program for changing the rotational speed continue until the intended number of start-stop cycles is reached or surface wear of the test friction pair reaches the main bearing material.

The results of the wear test of the test coating on the test bearing 3 are compared with the wear obtained on the control bearing 4 at a “standard” temperature, for example, t = 15 ° C.

If necessary, the control bearing 4 can also be additionally equipped with its own heater. A test coating may be applied to the test bearing. In this case, it becomes possible to conduct comparative tests of 2 different combinations of the tested coatings in a friction pair under the same conditions for bearings in terms of load and temperature.

The table shows examples of comparison of test results.

Table Bearing coating Temperature ° C Static load, kPa Wear of the blade / shaft, microns Number of cycles test subject No. 1 650 10.1 18/5 30000 control coating No. 1 fifteen 10.1 10/20 30000 control coating No. 1 427 10.1 18 / 7.6 30000

The invention allows to determine the comparative performance of the tested coatings in a friction pair, for example, a gas bearing, for example, in a gas-dynamic flap - between the shaft and the flap, at different operating temperatures and loads in relation to the "standard" known coating under standard conditions, for example at 15 ° C.

The use of the inventive stand for testing bearings in simulated operating conditions allows comparative testing of bearings with various coatings in the support of the turbine engine, improves the accuracy and reliability of obtaining test results and simplifies the design of the stand.

Claims (4)

1. A stand for testing bearings in simulated operating conditions, comprising a shaft with a drive pulse turbine, which is installed in a housing with channels for supplying a working fluid to the turbine wheel and withdrawing it from the turbine, a test bearing with a test coating applied to it, mounted in a cage located on the shaft of the impulse turbine and equipped with a heater, the cage of the test bearing is suspended inside the housing on elastic elements, in addition, the stand is equipped with a loading device, a temperature sensor and a sensor m of torque measurement, characterized in that a control bearing is inserted in it, mounted in a cage, which is suspended inside the housing on elastic elements, while the drive impulse turbine is located on the shaft in its middle part, which is mounted on two bearings, inside of which are symmetrically aligned relative to the pulse turbine are the control and test bearings, and the load device is connected to the bottom of the cage of the control and test bearings with the possibility of ensuring the same load narrow at both bearings, and between the turbine and the test bearing is situated separating the heat shield. 2. The stand according to claim 1, characterized in that the control bearing is additionally equipped with a heater and a temperature sensor. 3. The stand according to claim 1, characterized in that the test coating is applied to the control bearing. 4. The stand according to claim 1, characterized in that the design of the test and control bearings can be the same or different.

Images