CN101226104A - Apparatus for testing the take-off speed of elastic foil thrust bearings - Google Patents

Abstract

A device for testing the take-off speed of an elastic foil thrust bearing, including a drive system, a journal part and its lubrication system, and a data acquisition system; the drive system is composed of an asynchronous motor and a frequency converter, and the asynchronous motor is connected to the shaft through a high-speed flexible coupling One end of the neck is connected, and the journal is supported by two rolling bearings, and the rolling bearings are lubricated by an oil-air lubricator. The data acquisition system is composed of a sensor and its amplifier and a computer. The data measured by the sensor is collected by the acquisition card and input to the computer for storage. The rotor is driven by the motor, and the static load of the bearing is changed by the loading device, so the take-off speed of the foil bearing under different loads can be measured.

Description

Apparatus for testing the take-off speed of elastic foil thrust bearings

technical field

The invention relates to the technical field of performance testing of bearings, in particular to a device for testing the take-off speed of an elastic foil thrust bearing.

Background technique

The take-off speed of the thrust bearing is a sign of complete gas lubrication between the surface of the thrust disc and the working surface of the gas thrust bearing, and is also one of the important indicators of the dynamic pressure gas bearing. At present, the performance test of the elastic foil bearing is mainly to carry out the test experiment of the load capacity and the dynamic characteristic coefficient. Although some literatures mention that the bearing parameters and working conditions have an influence on the bearing take-off speed, there is no test device for the take-off speed. and identification methods. Some existing documents describe in detail the test method of the take-off speed of the oil film hydrostatic radial bearing, such as: "0n the lift-off speed in journal bearings" (published in "Tribology Letters" VOL20, NO.3-4, 2005.10, P299 -305) proposed to install a cantilever lever mechanism on the bearing housing, measure the friction coefficient of the bearing surface and the journal surface under different static loads and oil supply temperatures, and judge the take-off speed of the bearing through the Stribeck curve of the friction coefficient and speed, that is Friction coefficient method. However, for gas thrust bearings, the friction between the thrust disc and the bearing surface is not easy to measure, and it is difficult to identify the take-off speed of elastic foil gas bearings by the friction torque method. With the application of elastic foil gas bearings in high-speed rotating machines such as turbines and gas turbines, it is particularly important to determine the take-off speed through experiments.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a device for testing the take-off speed of the elastic foil thrust bearing, which can test the take-off speed of the elastic foil thrust bearing and identify the take-off speed through the displacement response spectrum method.

In order to achieve the above object, the technical solution of the present invention is: a device for testing the take-off speed of an elastic foil thrust bearing, comprising an asynchronous motor 1 and a frequency converter 16 connected thereto, the asynchronous motor 1 is connected to the shaft through a high-speed flexible coupling 2 The neck 7 is connected at one end, and the journal 7 is supported by the rolling bearing 6, which is installed on the rolling bearing housing 4; One end is installed with a thrust plate 9 and a thrust bearing seat 12 for fixing the thrust bearing 11 to be tested. The thrust bearing seat 12 is installed in the through hole of the thrust bearing fixing seat 10 through the shoulder, and the thrust bearing seat 12 is connected with the piston of the cylinder 13. , under the action of gas pressure, the thrust bearing seat 12 is driven by the cylinder 13 to generate axial movement, and an axial load is applied to the thrust bearing 11 to be tested; a measurement journal 7 is installed on the base 16 of the test bench at a position close to the motor end to measure the actual working speed The photoelectric speed sensor 15. An eddy current displacement sensor 8 with two probes pointing to the relative coordinate direction to test the radial displacement of the journal 7 in the horizontal direction and the vertical direction is installed at 90° in the middle position of the journal 7, and an eddy current displacement sensor 8 is installed on the thrust bearing seat 12 An eddy current displacement sensor 8 for measuring the relative axial displacement between the tested thrust bearing 11 and the surface of the thrust disc 9 .

Data collection is carried out by sensor 21, and the data that sensor 21 measures is amplified by amplifier 22 and is collected by acquisition card 23 and input computer 24 and stores, so that analyze; Said sensor 21 comprises photoelectric speed sensor 15 and all eddy current displacements sensor8.

The beneficial effect of the present invention is that: the rotor is driven by the asynchronous motor 1, and the static load of the bearing is changed by the loading device, so that the take-off speed of the foil thrust bearing under different loads can be measured.

Description of drawings

The structural principle and working principle of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Figure 1 is a schematic diagram of the structure of the tested elastic foil thrust bearing.

Fig. 2 is a schematic structural view of the elastic foil thrust bearing testing device of the present invention.

Figure 3 is a schematic diagram of the data acquisition system.

Fig. 4 is an illustration of the displacement response spectrum method to identify the take-off speed; wherein, Fig. 4 (a) is the axial displacement response spectrum diagram before take-off; Fig. 4 (b) is the axial displacement response spectrum diagram after take-off; abscissa Indicates the frequency; the ordinate indicates the magnitude of the displacement response.

Detailed ways

The structural principle and working principle of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the structure of the thrust bearing 11 to be tested includes a bottom foil 20, eight identical sector-shaped top foils 18 and supporting arch foils 19, and one end of the top foil 18 and supporting arch foils 19 is welded to the bottom foil 20 The bottom foil 18 is evenly distributed along the circumference of the bottom foil 20, and the other end is free. The part of the top foil 18 near the welding end is a conical surface, which can form a convergent air film gap with the surface of the thrust plate 9. During the test, the thrust disc 9 was rotated in the direction from the welding end to the free end.

Referring to Fig. 1 and Fig. 2, a device for testing the take-off speed of an elastic foil thrust bearing includes a drive system, a journal part and its lubrication system, and a data acquisition system; the drive system includes an asynchronous motor 1 and a frequency converter 16 connected thereto , the journal 7 is driven by a high-speed medium-frequency asynchronous motor 1, and one end is connected with the drive motor 1 through a high-speed flexible coupling 2, and the speed of the motor 1 can be adjusted by adjusting the parameters of the frequency converter 16; the journal 7 is a symmetrical structure, with Two rolling bearings 6 with identical parameters are supported. The rolling bearing 6 is installed in the rolling bearing seat 4 and preloaded by a spring 3. The rolling bearing 6 communicates with an oil-air lubricator 17 through the oil-air passage 5 on the rolling bearing seat 4. The lubricating oil After being gasified by the oil-air lubricator 17, it is sent to the rolling bearing 6 through the oil-air channel 5 for lubrication, so as to prevent the rolling bearing 6 from failure and damage, ensure its normal operation, and prolong the service life of the bearing; the thrust disc 9 is installed on the other end of the journal 7 , its working surface is in the same plane as the side of the thrust bearing holder 10, and the thrust bearing 11 to be tested is mounted on the thrust bearing holder 12 through pins. The piston rod of the cylinder 13 is screwed and connected with the threaded hole of the thrust bearing seat 12, and the compressed gas can be passed into the cylinder 13 to push the piston to generate displacement, and the thrust disc 9 and the top layer of the thrust bearing can be changed by driving the thrust bearing seat 12 to generate axial displacement. The air film gap between the surfaces of the foil 18 is used to achieve the purpose of changing the static load of the thrust bearing 11 under test. In this test bench test, the gas pressure input to the cylinder 13 can be obtained by a pressure gauge installed on the intake pipe, and a photoelectric speed sensor for measuring the actual working speed of the journal 7 is installed on the base 16 of the test bench near the motor end. 15. An eddy current displacement sensor 8 with two probes pointing to the relative coordinate direction to test the radial displacement of the journal 7 in the horizontal direction and the vertical direction is installed at 90° in the middle position of the journal 7, and an eddy current displacement sensor 8 is installed on the thrust bearing seat 12 An eddy current displacement sensor 8 for measuring the relative axial displacement between the tested thrust bearing 11 and the surface of the thrust disc 9 .

Referring to Fig. 3, data collection system of the present invention is made up of sensor 21 and its amplifier 22 and computer 24, and all sensors 21 all have respective amplifier 22, and the amplifier signal of output is carried out with certain sampling frequency with high-speed multi-function acquisition card 23 The data is collected and stored by a computer 24 for off-line or on-line processing; said sensor 21 includes a photoelectric rotational speed sensor 15 and three eddy current displacement sensors 8 .

After the test, the take-off speed of the thrust bearing 11 under test is identified by the displacement response spectrum method, the axial displacement measured by the displacement sensor 8 is intercepted segment by section and FFT transformation is performed, and the change of the spectrogram is observed in the frequency domain to identify the take-off speed, as shown in Fig. 4. The spectrogram changes from irregular shape to regular shape before and after take-off, and the speed corresponding to the transition point is the take-off speed.

The working principle of the present invention is: the process of testing the take-off speed of the thrust bearing 11 by the test device of the present invention is that after the installation and debugging of each part of the test bench is completed, at first adjust the operating parameters of the frequency converter 16 to set the operating speed of the asynchronous motor 1 and speed-up time, and start the oil-air lubricator 17 to lubricate the rolling bearing 6, open the computer 24 to start the data acquisition system; then start the frequency converter 16 to make the motor 1 drive the journal 7 to rotate, and now all the sensors 21 start to work and pass through the acquisition card 23 samples the data of each sensor; when the speed of the motor 1 reaches the set operating speed, the frequency converter 16 is turned off to gradually decelerate the motor 1 until it stops working, and finally the computer 24 is used to store the sampling data of all sensors for analysis. After the experiment is over, the take-off speed of the thrust bearing 11 under test can be identified by the displacement response spectrum method, that is, the axial displacement signal measured by the eddy current displacement sensor 8 is taken for analysis, and the displacement signal is intercepted segment by segment for FFT transformation, and observed in the frequency domain Spectrum changes to identify takeoff RPM.

Claims (4)

1. the device of a testing elastic foil tablet thrust bearing departure rotary speed, comprise an asynchronous machine (1) and connected frequency converter (16), it is characterized in that, asynchronous machine (1) is connected with axle journal (7) one ends by high speed flexible connection (2), axle journal (7) is supported by rolling bearing (6), the thrust metal (12) that thrust disc (9) is installed and is used for fixing tested thrust bearing (11) at the other end of axle journal (7), thrust metal (12) is installed in the through hole of thrust bearing holder (10) by the shaft shoulder, thrust metal (12) is connected with the piston of cylinder (13), go up the photoelectric sensor (15) that the real work rotating speed of a measurement axle journal (7) is installed near the position of motor side at experiment table pedestal (16), being set to 90 ° in the interposition of axle journal (7) is equipped with two probes and points to the relative coordinate directions, test axle journal (7) in the horizontal direction with the eddy current displacement sensor (8) of the radial displacement of vertical direction, go up at thrust metal (12) eddy current displacement sensor (8) of measuring the displacement to axial between tested thrust bearing (11) and thrust disc (9) surface be installed.

2. the device of a kind of testing elastic foil tablet thrust bearing departure rotary speed according to claim 1 is characterized in that, described rolling bearing (6) is connected with an oil-air lubrication device (17).

3. the device of a kind of testing elastic foil tablet thrust bearing departure rotary speed according to claim 1 is characterized in that, the side of the workplace of said thrust disc (9) and thrust bearing holder (10) is in same plane.

4. the device of a kind of testing elastic foil tablet thrust bearing departure rotary speed according to claim 1, it is characterized in that, said photoelectric sensor (15) or eddy current displacement sensor (8) all have amplifier (22) separately, the amplifier signal of output carries out data acquisition with high-speed multifunctional capture card (23), and stores with computing machine (24).

Images