A protection bearing life tester for a vertical magnetic bearing system

Abstract

A kind of vertical magnetic bearing system protection bearing life tester, upper test tooling is equipped in tester main body, electromagnet tray is installed on upper test tooling, self-clearance electromagnet is installed on electromagnet tray, upper magnetic suction support seat is pressed in the top surface of self-clearance electromagnet, lower magnetic suction support seat is located below self-clearance electromagnet, upper and lower magnetic suction support seat are respectively embedded buffer rubber ring, the buffer rubber ring of lower magnetic suction support seat is in contact with the lower end surface of protection bearing outer ring, the buffer rubber ring of upper magnetic suction support seat is located above protection bearing outer ring;First self-clearance L1 is left between lower magnetic suction support seat and self-clearance electromagnet, second clearance L2 is left between the buffer rubber ring of upper magnetic suction support seat and the upper end surface of protection bearing outer ring, third adjustment clearance L3 is left between the upper end surface of protection bearing inner ring and the upper impact pad of main shaft, and L3>L1>L2.The present application can self-clearance main shaft drop distance, and it is important to the improvement of protection bearing impact resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of bearing testing, and particularly relates to a protection bearing life tester of a vertical magnetic bearing system. BACKGROUND

[0002] Unlike traditional bearings, magnetic bearings rely on a complete control system to ensure normal operation, and thus have a much higher production cost than traditional bearings. When active magnetic bearings fail due to overload or power failure, the high-speed rotating rotor falls onto the protection bearings, which can cause a huge collision impact and friction heat, and can lead to deformation failure of the protection bearings or rotor burn or even destruction of the entire magnetic bearing system. In order to better reduce costs while ensuring the safety and stability of the magnetic bearing system, it is quite important to install a pair of protection bearings with good impact resistance at both ends of the system.

[0003] The protection bearing is the "safety guard" of the magnetic suspension system, a strong support for the breakthrough and leap-forward development of high-tech, an important guarantee for high-end equipment manufacturing, and a bridge for the transformation of high-tech into productive forces. Vigorously promoting the research of protection bearings provides protection for the safety and stability of the magnetic suspension system, is the only way to realize the localization of high-end equipment, is the inevitable choice to respond to the development trend of the world manufacturing industry and enhance the core competitiveness of the industry, and is an important measure to accelerate the transformation of China's economic development mode, promote the industrialization of China, and build a manufacturing power.

[0004] After the failure or overload of the magnetic bearing, the high-speed rotating rotor falls, which brings huge vibration and impact to the protection bearing, and the reverse vortex formed by the collision and friction of the bearing inner ring can intensify the intensity of the collision movement. The impact greatly shortens the service life of the protection bearing. Therefore, the research on the impact resistance of the protection bearing of the magnetic suspension system is related to the length of the service life of the entire magnetic suspension system.

[0005] The axial falling and collision force between the main shaft and the inner ring of the protection bearing is the main reason for the failure of the protection bearing in the current vertical magnetic bearing system. How to reduce the axial collision force between the two has become the main research direction for improving the impact resistance of the protection bearing and prolonging the service life of the magnetic bearing system. At present, the protection bearing in the magnetic bearing system is mostly an angular contact ball bearing, which can only withstand 1-2 rotor falls and is damaged, and the protection bearing in the equipment needs to be replaced several times to prevent rotor burn. In addition, some studies use deep groove ball bearings, sliding bearings, double-layer protection bearings, cylindrical roller bearings, etc. as protection bearings. These types of bearings can improve the impact resistance of the protection bearing in some aspects, but also have certain defects, and their service life is generally low. Therefore, it is of great significance to study a self-clearing gap mechanism to improve the impact resistance of the protection bearing. SUMMARY

[0006] The vertical magnetic bearing system protection bearing life tester of the present application can reduce the axial collision force borne by the protection bearing, improve the impact resistance of the protection bearing, and provide reliable basis for improving the working life of the protection bearing and the machining process, and meet the technical requirements of the user for the life and precision of the magnetic bearing system.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a vertical magnetic bearing system protection bearing life tester, wherein the magnetic bearing system is installed on the tester main body, the main shaft of the magnetic bearing system is provided with a protection bearing, an upper test tool is arranged on the upper part of the tester main body, an electromagnet tray is installed on the upper test tool, a self-clearing gap electromagnet is installed on the electromagnet tray, an upper pressing cover is connected with the upper test tool and presses the upper magnetic attraction support seat against the top surface of the self-clearing gap electromagnet, a lower magnetic attraction support seat is located below the self-clearing gap electromagnet and is in gap cooperation with the electromagnet tray, the end part of the lower magnetic attraction support seat and the upper magnetic attraction support seat is respectively provided with a clamping groove, and a buffer rubber ring is embedded in the clamping groove, wherein the buffer rubber ring of the lower magnetic attraction support seat is in contact with the lower end surface of the outer ring of the protection bearing, and the buffer rubber ring of the upper magnetic attraction support seat is located above the outer ring of the protection bearing.

[0008] A first self-clearing gap L1 is left between the lower magnetic attraction support seat and the self-clearing gap electromagnet, a second gap L2 is left between the buffer rubber ring of the upper magnetic attraction support seat and the upper end surface of the outer ring of the protection bearing, and a third adjustment gap L3 is left between the upper collision pad of the main shaft and the upper end surface of the inner ring of the protection bearing, and L3>L1>L2.

[0009] The protection bearing is a pair of angular contact ball bearing assemblies.

[0010] The upper sensor seat is installed on the lower magnetic attraction support seat, and the inner surface of the upper sensor seat is adjacent to the outer ring of the protection bearing and leaves a gap.

[0011] The main shaft is integrated with a motor rotor, a gap adjustment assembly and a weight adjustment assembly on the shaft center to form a rotating shaft system required for the test, and the gap adjustment assembly includes an upper gap adjustment assembly and a lower gap adjustment assembly.

[0012] The upper gap adjustment assembly is arranged in the upper test tool and includes an upper pressing nut and an upper gap adjustment pad, the upper pressing nut is threadedly connected to the main shaft and presses the upper collision pad against the upper end surface of the upper gap adjustment pad, the upper gap adjustment pad rotates with the main shaft, the upper gap adjustment pad is a hollow stepped shaft, the outer circular surface of the upper gap adjustment pad is a stepped shaft surface, and the protection bearing is located on the small diameter section of the stepped shaft surface.

[0013] A fourth adjustment gap L4 is left between the inner ring of the protection bearing and the outer circular surface of the upper gap adjustment pad, and a fifth adjustment gap L5 is left between the lower end surface of the inner ring of the protection bearing and the stepped surface of the upper gap adjustment pad.

[0014] The maximum outer diameter of the upper pressing nut and the upper impact washer is less than the maximum diameter of the inner ring of the protection bearing, so as to form a window for detecting the movement of the inner ring of the bearing or the roller.

[0015] The lower part of the test machine body is provided with a lower test tool, and a test bearing and the lower gap adjusting assembly are arranged between the lower test tool and the main shaft.

[0016] The lower gap adjusting assembly comprises a lower impact ring, a lower protection ring, a lower bearing gland and a lower nut, the lower impact ring is fixedly sleeved at the lower end of the main shaft, the outer ring of the test bearing is installed in the lower test tool and is axially positioned by the lower nut and the lower protection ring, and the inner ring of the test bearing is gap-fitted with the lower impact ring.

[0017] The weight adjusting assembly comprises a counterweight disc, a counterweight disc adjusting ring, a counterweight disc pressing cap and a counterweight disc cone sleeve, the counterweight disc is arranged on the outer cylindrical surface of the counterweight disc cone sleeve, the counterweight disc pressing cap is used to press the counterweight disc and the counterweight disc cone sleeve on the tapered surface of the main shaft through threads, and the counterweight disc adjusting ring is installed on the main shaft and is in contact with the upper end surface of the counterweight disc cone sleeve.

[0018] The beneficial effects of the present application are that: the present application suspends the main shaft by means of the magnetic bearing system, and after the motor is accelerated to a preset rotating speed, the motor and the magnetic suspension system are subjected to power-off and demagnetization treatment, and at the same time, the upper end of the test machine is caused to respond to power-on magnetism of the self-clearing gap electromagnet, the lower magnetic suction support seat is caused to move up to hold the outer ring of the bearing, so as to automatically reduce the axial protection gap of the main shaft falling; in addition, the structure design of the buffer rubber ring, the coupling effect of the two can greatly reduce the axial impact force of the main shaft and the inner ring of the protection bearing, can effectively improve the impact resistance of the protection bearing, and finally realize increasing the anti-falling times of the protection bearing, that is, prolonging the service life of the protection bearing.

[0019] In the present application, different bearing inner diameters can be installed by replacing the gap adjusting assembly, such as the upper gap adjusting pad (the thickness of the adjusting pad), so as to realize the bearing applicability in a certain range, and also increase the application range of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present application;

[0021] Figure 2 It is a self-clearing gap mechanism and protection bearing installation structure schematic diagram in the present application;

[0022] Figure 3 It is a magnetic bearing installation structure schematic diagram in the present application;

[0023] Figure 4 It is a test bearing installation structure schematic diagram in the present application;

[0024] Figure 5The structural schematic diagram of the weight adjusting assembly in the application is shown in the figure.

[0025] Figure 6 The overall appearance schematic diagram of the testing machine in the application is shown in the figure.

[0026] Marked in the figure: 1-lower bottom plate; 2-supporting plate; 3-upper bottom plate; 4-lower flange; 5-motor balance ring; 6-motor rotor; 7-motor stator; 8-motor water jacket; 9-motor base; 10-magnetic bearing mounting seat; 11-housing; 12-upper testing tool; 13-upper pressing cover; 14-upper protective cover; 15-upper gap adjusting pad; 16-upper collision pad; 17-upper pressing nut; 18-①upper magnetic attraction supporting seat; 18-②lower magnetic attraction supporting seat; 19-upper sensor seat; 20-self-eliminating gap electromagnet; 21-buffer rubber ring; 22-limiting pad; 23-radial magnetic bearing; 24-magnetic bearing pad; 25-axial magnetic bearing; 26-main shaft; 27-axial gap adjusting ring; 28-axial magnetic bearing positioning ring; 29-counterweight disc adjusting ring; 30-counterweight disc cone sleeve; 31-counterweight disc; 32-lower transition disc; 33-counterweight disc pressing cap; 34-lower testing tool; 35-lower collision ring; 36-lower sensor mounting seat; 37-lower protective ring; 38-lower bearing pressing cover; 39-lower nut; 40-supporting plate; 500-upper sensor; 501-protective bearing a; 502-protective bearing b; 503-electromagnet tray. DETAILED DESCRIPTION

[0027] The application will be further described in detail below in combination with the drawings and examples, but it is not taken as any limitation on the application.

[0028] Example 1: A protective bearing life testing machine of a vertical magnetic bearing system, comprising a testing machine main body, a self-eliminating gap electromagnet mechanism, a magnetic bearing system, a variable frequency speed regulation system and a testing monitoring system. The magnetic bearing system is installed on the testing machine main body, and the magnetic bearing system comprises a main shaft 26, a radial magnetic bearing 23 and an axial magnetic bearing 25, the upper end of the main shaft 26 is installed with a protective bearing, and the lower end is installed with a test bearing 200.

[0029] As shown in Figure 1 , 6 , the testing machine main body mainly comprises a lower bottom plate 1, an upper bottom plate 3, a motor base 9, an upper testing tool 12, a lower testing tool 34 and a motor.

[0030] The lower bottom plate 1 is firmly fixed to the ground, and four support plates 40 are fixed on the lower bottom plate 1 to support the entire testing machine. The upper end of the four support plates 40 is fixedly connected to the upper bottom plate 3, and the lower flange 4 is installed on the upper bottom plate 3 by bolts. The inner edge of the upper surface of the lower flange 4 is connected to the motor base 9, and the motor balance ring 5 is installed at the bottom of the motor base 9. A motor for driving the main shaft 26 to rotate is installed in the motor base 9. The motor stator 7 is fixedly connected to the motor base 9, and the motor rotor 6 is installed in the middle part of the main shaft 26. The lower end of the shell 11 of the main body of the testing machine is fixed to the motor base 9, and the upper end of the shell 11 is connected to the upper testing tool 12. The upper protective cover 14 is connected to the upper pressing cover 13 by bolts. The lower testing tool 34 is fixedly connected to the lower surface of the lower flange 4 through the lower transition disc 32, and the lower part of the lower testing tool 34 is installed with the test bearing 200 for protecting and supporting the main shaft 26. The test bearing 200 is a deep groove ball bearing.

[0031] As shown in Figure 1 The upper end of the upper testing tool 12 is fixedly connected to the shell 11, and the protective bearings in the upper testing tool 12 include protective bearing a 501 and protective bearing b 502, which are a pair of face-to-face installed angular contact ball bearing groups installed on the upper end of the main shaft 26.

[0032] The main structure of the electromagnetic self-cancellation gap mechanism and the cooperation relationship with the protective bearing are as shown in Figure 2 The electromagnet tray 503 is installed on the upper testing tool 12 by bolts, and the self-cancellation gap electromagnet 20 is installed on the electromagnet tray 503. The upper pressing cover 13 is connected to the upper testing tool 12 by bolts, and the upper magnetic attraction support seat 18-① is pressed tightly on the top surface of the self-cancellation gap electromagnet 20. The lower magnetic attraction support seat 18-② is located below the self-cancellation gap electromagnet 20 and cooperates with the electromagnet tray 503. The end part of the lower magnetic attraction support seat 18-② and the upper magnetic attraction support seat 18-① is provided with a clamping groove, and a buffer rubber ring 21 is embedded in the clamping groove. The buffer rubber ring 21 of the lower magnetic attraction support seat 18-② is in contact with the lower end surface of the outer ring of the protective bearing b 502, so as to realize the lifting of the protective bearing group as a whole when the magnetic attraction is lifted. The buffer rubber ring 21 of the upper magnetic attraction support seat 18-① is located above the outer ring of the protective bearing a 501.

[0033] The first self-cancellation gap L1 is left between the lower magnetic attraction support seat 18-② and the self-cancellation gap electromagnet 20. The second gap L2 is left between the buffer rubber ring 21 of the upper magnetic attraction support seat 18-① and the upper end surface of the outer ring of the protective bearing a 501. The third adjustment gap L3 is left between the upper end surface of the inner ring of the protective bearing a 501 and the upper impact pad 16 of the main shaft 26 after the main shaft is suspended, and L3>L1>L2.

[0034] The third adjustment gap L3 is the axial protection gap of the main shaft, and is also the falling distance of the main shaft. In the test, the magnetic bearing system suspends the main shaft 26, and accelerates the main shaft 26 to a preset rotating speed through the motor, then the motor and the magnetic bearing system are powered off and magnetized off, and at the same time, the upper end of the test machine is caused to respond to the power-on magnetization of the self-clearing gap electromagnet 20 to attract the lower magnetic suction support base 18-② to drive the protection bearing to quickly lift to clear the first self-clearing gap L1, and the third adjustment gap L3 is reduced due to the axial lifting of the bearing as a whole (i.e. the axial lifting of the bearing inner ring), and the falling distance L3ʹ=L3-L1 is reduced, i.e. the falling distance is reduced, and the axial impact force is reduced.

[0035] Further, the upper sensor seat 19 is installed on the lower magnetic suction support base 18-②, and the inner surface of the upper sensor seat 19 is adjacent to the protection bearing outer ring with a gap.

[0036] Embodiment 2: This embodiment is a detailed introduction to the installation of the magnetic bearing in the magnetic bearing system based on embodiment 1.

[0037] As shown in Figure 1 , 3 , the housing of the test machine body is also provided with a magnetic bearing mounting seat 10, the two ends of the magnetic bearing mounting seat 10 are connected with the upper test tool 12 and the motor base 9 respectively, and the axial magnetic bearing 25 and the radial magnetic bearing 23 for installing the magnetic bearing system are installed in the magnetic bearing mounting seat 10.

[0038] The radial magnetic bearing 23 is provided with two and is arranged in an upper and lower interval, the stator mounting seat of the radial magnetic bearing 23 is mounted on the inner side of the magnetic bearing mounting seat 10, the stator of the radial magnetic bearing 23 is mounted in the stator mounting seat, and the main shaft 26 is taken as the rotor of the radial magnetic bearing 23, and after the two radial magnetic bearings 23 are powered on and magnetized, the main shaft 26 can be well centered, so that the main shaft 26 rotates stably and does not oscillate to a large extent.

[0039] The axial magnetic bearing 25 is also provided with two, which are located below the two radial magnetic bearings 23 and are arranged in an upper and lower interval, and a large diameter section is arranged on the main shaft 26, the upper axial magnetic bearing 25 and the lower axial magnetic bearing 25 are arranged opposite to each other at the upper and lower end surfaces of the large diameter section, and the two axial magnetic bearings 25 are powered on and magnetized and powered off and demagnetized, so that the main shaft 26 can complete the process of floating up by magnetic force and falling down by gravity.

[0040] Embodiment 3: This embodiment is based on embodiment 1, and integrates a gap adjustment assembly on the main shaft 26, which includes an upper gap adjustment assembly and a lower gap adjustment assembly.

[0041] As shown in Figure 1 , Figure 2As shown, the upper gap adjustment assembly is arranged in the upper test tool 12, including an upper pressing nut 17, an upper impact washer 16 and an upper gap adjustment washer 15. The upper gap adjustment washer 15 is installed on the main shaft 26 and moves with the main shaft 26. The upper gap adjustment washer 15 is a hollow stepped shaft, the outer circular surface of which is a stepped shaft surface. The protective bearing is located on the small diameter section of the stepped shaft surface and between the small diameter section and the inner circular surface of the upper sensor seat 19.

[0042] As shown in Figure 2 , a fourth adjustment gap L4 is left between the inner ring of the protective bearing and the outer circular surface of the upper gap adjustment washer 15, and a fifth adjustment gap L5 is left between the inner ring of the protective bearing and the stepped surface of the upper gap adjustment washer 15. When the axial magnetic bearing 25 is powered on and powered off, the main shaft 26 can move axially relative to the inner ring of the protective bearing. The upper pressing nut 17 and the upper impact washer 16 are installed on the main shaft 26. The upper pressing nut 17 is threadedly connected to the main shaft 26 and presses the upper impact washer 16 against the end surface of the inner ring of the protective bearing and the upper end surface of the upper gap adjustment washer 15. The upper impact washer 16 is pre-pressed by the pre-tightening of the upper pressing nut 17 and the self-weight of the main shaft system. At this time, the upper impact washer 16 is in contact with the end surface of the inner ring of the protective bearing, so that the main shaft 26 falls to the inner ring of the protective bearing and drives the inner ring of the protective bearing to rotate.

[0043] When the axial magnetic bearing 25 is powered on, the main shaft 26 floats upward, driving the upper impact washer 16 to separate from the end surface of the inner ring of the protective bearing. The third adjustment gap L3 is formed between the upper impact washer 16 and the end surface of the inner ring of the protective bearing.

[0044] In order to adapt to different sizes of protective bearings, the end surface of the upper impact washer 16 can be repaired to make the third adjustment gap L3 reach the required axial protection gap in the experiment. Similarly, the outer diameter and end surface size of the upper gap adjustment washer 15 can be repaired to make the fourth adjustment gap L4 and the fifth adjustment gap L5 reach the required radial gap and axial gap in the experiment. When the protective bearing is replaced, the upper gap adjustment washer 15 needs to be replaced to ensure that the gap size between the two meets the experimental requirements.

[0045] As shown in Figure 2 , further, the maximum outer diameter of the upper pressing nut 17 and the upper impact washer 16 is smaller than the maximum diameter of the inner ring of the protective bearing. Therefore, the movement of the inner ring or even the bearing ball can be observed from the outside, so as to facilitate the speed measurement and temperature measurement of the sensor.

[0046] As shown in Figure 1 , 4As shown, the lower gap adjusting assembly comprises a lower impact ring 35, a lower protection ring 37, a lower bearing gland 38 and a lower nut 39, the lower impact ring 35 is sleeved and fixed at the lower end of the main shaft 26, the outer ring of the test bearing 200 is installed in the lower test tool 34 and is axially positioned by the lower nut 39 and the lower protection ring 37, the inner ring of the test bearing 200 is in clearance fit with the lower impact ring 35. When the test bearing 200 is replaced, the outer diameter size of the lower impact ring 35 and the lower nut 39 can be repaired to meet the requirement of the radial clearance required by the index.

[0047] Further, the sixth adjusting gap L6 is left between the upper sensor seat 19 and the upper magnetic attraction support seat 18-①, the seventh adjusting gap L7 is left between the lower magnetic attraction support seat 18-② and the rotor step surface, and the eighth adjusting gap L8 is left between the axial magnetic bearing 25 and the main shaft 26. Figure 3 As shown, the axial magnetic bearing 25 and the main shaft are axially left with the air gap L8 in the normal working state, and the radial magnetic bearing 23 and the main shaft 26 are radially left with the air gap L9 in the normal working state.

[0048] In the magnetic bearing system in the application, the size of the axial magnetic bearing air gap L8 and the distance between the upper gap adjusting pad 15 and the inner ring of the protection bearing should be coordinated with each other, the distance between the upper gap adjusting pad 15 and the inner ring of the protection bearing is too small, when the axial magnetic bearing 25 is magnetized and the main shaft 26 is floated, the inner ring of the protection bearing is also lifted by the upper gap adjusting pad 15, at this time, the bearing inner ring is accelerated to reduce the service life of the protection bearing due to external friction, the testing machine is damaged, unnecessary personal safety hazards and property losses are brought.

[0049] Therefore, there is a certain quantitative relationship between the nine gaps in the application, when the magnetic bearing is normally working and the main shaft is suspended in the air, L2=0.2<L1=0.3<L3=0.5<L8=0.6, L6=1.4>L1, L4=0.5<L9=0.6, L5 / L7>L8.

[0050] Embodiment 4: This embodiment is based on the above-mentioned embodiments, and a weight adjusting assembly is further integrated on the main shaft 26, which is used for adding counterweight to the main shaft 26 and adjusting the counterweight according to the test requirements. Figure 1 、 5As shown, the weight adjustment assembly includes counterweight disc 31, counterweight disc adjustment ring 29, counterweight disc pressing cap 30 and counterweight disc cone sleeve 30, etc. Counterweight disc 31 is mounted on the outer cylindrical surface of counterweight disc cone sleeve 30, and counterweight disc pressing cap 30 is screwed to compress counterweight disc 31 and counterweight disc cone sleeve 30 on the tapered surface of main shaft 26. The tapered surface is machined to ensure the fit, so that the centering accuracy of counterweight disc 31 after installation is very high. The tapered surface positioning has the advantage that the accuracy is not lost after multiple disassembly and assembly. Anti-loosening jacks are installed on counterweight disc pressing cap 30 to tightly press the end surface of counterweight disc cone sleeve 30 to prevent counterweight disc 31 from loosening from the tapered surface during high-speed operation. Counterweight disc adjustment ring 29 is mounted on main shaft 26 and located between counterweight disc 31 and motor balance ring 5 to limit the distance between counterweight disc 31 and the motor.

[0051] So far, the main shaft integrates motor rotor, gap adjustment assembly and weight adjustment assembly on the shaft center to form the rotating shaft system required for the test.

[0052] In summary, the test machine main body has three loading methods to apply pre-load to the outer ring of the protection bearing: one is to load pre-load through counterweight disc 31, one is to load pre-load through upper compression nut 17, and one is that the weight of main shaft 26 and various component assemblies can be used as the pre-load of the fixed bearing outer ring.

[0053] Further, in the above embodiments, the variable frequency speed regulation system includes a variable frequency speed regulation motor, a frequency converter, a speed feedback system and a computer system. The part of the structure can be connected by using commercially available products, so part of the structure is not shown in the figure. The variable frequency speed regulation motor is the motor installed in the motor base of the above test machine main body to drive the main shaft to rotate. The computer system is connected with the frequency converter through communication and speed feedback system, can read the parameters in the frequency converter, can send motor speed adjustment instruction to the frequency converter to control the output frequency of the frequency converter, and can meet the speed regulation requirement of 20-20000r / min. The variable frequency speed regulation motor includes motor balance ring 5, motor rotor 6, motor stator 7, motor water jacket 8, motor base 9, etc.

[0054] The test monitoring system includes speed sensor, vibration sensor, temperature sensor, displacement sensor, and data can be transmitted to computer system for monitoring and observation to monitor, predict and judge the damage time of the protection bearing. For example, abnormal vibration, rapid temperature rise, and disordered shaft center displacement trajectory are used as judgment indexes. The number of times of impact and drop resistance of the protection bearing is measured under the condition that the self-cancelling gap mechanism reduces the axial collision force of the main shaft, that is, the service life of the protection bearing is measured.

[0055] The above examples are only used to illustrate the technical solutions of the present application but not to limit the present application. It should be understood by those skilled in the art that the specific embodiments of the present application can be modified or replaced equivalently with reference to the above examples, and any modification or equivalent replacement without departing from the spirit and scope of the present application is within the protection scope of the claims of the application.

Claims

1. A protective bearing life testing machine for a vertical magnetic bearing system, wherein the magnetic bearing system is mounted on the main body of the testing machine, and a protective bearing is installed on the spindle of the magnetic bearing system, characterized in that: An upper test tool is arranged on the upper part of the test machine body, the electromagnet tray is arranged on the upper test tool, the self-clearance electromagnet is arranged on the electromagnet tray, the upper magnetic attraction support seat is connected with the upper test tool and is pressed on the top surface of the self-clearance electromagnet, the lower magnetic attraction support seat is located below the self-clearance electromagnet and is in clearance fit with the electromagnet tray, the end parts of the lower magnetic attraction support seat and the upper magnetic attraction support seat are respectively provided with clamping grooves, and buffer rubber rings are embedded in the clamping grooves, wherein the buffer rubber ring of the lower magnetic attraction support seat is in contact with the lower end surface of the outer ring of the protection bearing, and the buffer rubber ring of the upper magnetic attraction support seat is located above the outer ring of the protection bearing; The first self-clearance gap L1 is left between the lower magnetic attraction support seat and the self-clearance electromagnet, the second gap L2 is left between the buffer rubber ring of the upper magnetic attraction support seat and the upper end surface of the outer ring of the protection bearing, and the third adjustment gap L3 is left between the upper impact pad of the main shaft and the upper end surface of the inner ring of the protection bearing, and L3>L1>L2; When the magnetic bearing system fails, the self-clearance electromagnet is electrified to generate electromagnetic force to drive the lower magnetic attraction support seat to move upward, clear the first self-clearance gap L1, and lift the protection bearing to move axially upward as a whole, so that the axial falling distance of the main shaft is reduced to the difference between L3 and L1.

2. The protection bearing life tester for a vertical magnetic bearing system according to claim 1, characterized by: The protection bearing is a pair of angular contact ball bearings assembled face to face.

3. The protection bearing life tester for a vertical magnetic bearing system according to claim 1, characterized by: The upper sensor seat is arranged on the lower magnetic attraction support seat, and the inner surface of the upper sensor seat is adjacent to the outer ring of the protection bearing and leaves a gap.

4. The protection bearing life tester for a vertical magnetic bearing system according to claim 1, characterized by: The main shaft is integrated with a motor rotor, a gap adjustment assembly and a weight adjustment assembly on the shaft center to form a rotating shaft system required by the test.

5. The protection bearing life tester for a vertical magnetic bearing system according to claim 4, characterized by: The upper gap adjustment assembly is arranged in the upper test tool and includes an upper pressing nut and an upper gap adjustment pad.

6. The protection bearing life tester for a vertical magnetic bearing system according to claim 5, characterized by: The upper pressing nut is threadedly connected to the main shaft and presses the upper impact pad on the upper end surface of the upper gap adjustment pad, the upper gap adjustment pad rotates with the main shaft, the upper gap adjustment pad is a hollow stepped shaft, the outer cylindrical surface of which is a stepped shaft surface, and the protection bearing is located on the small-diameter section of the stepped shaft surface.

7. The protection bearing life tester for a vertical magnetic bearing system according to claim 5, characterized by: The fourth adjustment gap L4 is left between the inner ring of the protection bearing and the outer cylindrical surface of the upper gap adjustment pad, and the fifth adjustment gap L5 is left between the lower end surface of the inner ring of the protection bearing and the stepped surface of the upper gap adjustment pad.

8. The protection bearing life tester for a vertical magnetic bearing system according to claim 4, characterized by: The maximum outer diameters of the upper pressing nut and the upper impact pad are smaller than the maximum diameter of the inner ring of the protection bearing, so as to form a window for detecting the movement of the inner ring of the bearing or the rollers.

9. The protection bearing life tester for a vertical magnetic bearing system according to claim 8, characterized by: The lower part of the test machine body is provided with a lower test tool, and the test bearing and the lower gap adjustment assembly are arranged between the lower test tool and the main shaft. The lower gap adjustment assembly includes a lower impact ring, a lower protection ring, a lower bearing pressing nut and a lower nut, the lower impact ring is fixedly sleeved on the lower end of the main shaft, the outer ring of the test bearing is arranged in the lower test tool and is axially positioned by the lower nut and the lower protection ring, and the inner ring of the test bearing is in clearance fit with the lower impact ring.

10. The protection bearing life tester for a vertical magnetic bearing system according to claim 4, characterized by: The weight adjusting assembly comprises a counterweight disc, a counterweight disc adjusting ring, a counterweight disc pressing cap and a counterweight disc cone sleeve, the counterweight disc is arranged on the outer cylindrical surface of the counterweight disc cone sleeve, the counterweight disc pressing cap is used to press the counterweight disc and the counterweight disc cone sleeve on the tapered surface of the main shaft through screw thread, and the counterweight disc adjusting ring is installed on the main shaft and is in contact with the upper end surface of the counterweight disc cone sleeve.

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