Electromagnetic vibration gear bending fatigue test bench

Abstract

The present invention discloses an electromagnetic vibration gear bending fatigue test bench. It includes a servo motor, a base, a measuring system, an electromagnetic resonance system and a variable mass excitation system, etc. The servo motor is connected to a ball screw, which is connected to the base; the bottom of the base is connected to the ground through a spring, and there are two guide holes on the base with guide rods installed; the upper part of the electromagnetic resonance system is connected to the variable mass system, the middle part is connected to the upper connecting plate through a spring, and the lower part is connected to a loading unit, and a test specimen is installed between the loading unit and the base. The present invention can effectively isolate the influence of environmental vibration sources on the equipment and the influence of the equipment on the surrounding environment; the specimen is loaded by electromagnetic vibration, and a strain gauge is provided, which can monitor the root stress and the resonant frequency of the loading in real time, and accurately judge the gear damage by the changes in the root stress and the vibration frequency. The present invention is provided with an environmental chamber, which can carry out fatigue tests in high or low temperature environments.

Description

Technical Field

[0001] The invention relates to a gear testing device in the technical field of mechanical fatigue testing devices, and in particular to an electromagnetic vibration gear bending fatigue testing platform and a fatigue testing method. Background Art

[0002] Gear transmission is widely used in the fields of automobiles, engineering machinery, aerospace, etc. The fatigue strength of gears has a decisive influence on the safety and reliability of the entire transmission system. The gear fatigue test bench can develop the fatigue characteristics of gears. With the improvement of the requirements for gear transmission equipment in various industries, the research and development of gear fatigue test benches has an urgent need and practical value.

[0003] When conducting a gear bending fatigue test, the load applied to the gear teeth is a force tangent to the base circle. The root stress needs to be calculated using an analytical method, but the calculated value is often different from the true value. Current test benches cannot directly measure the root bending stress. Some gears operate at specific ambient temperatures, but existing equipment cannot perform bending fatigue tests under specific conditions. Therefore, the present invention proposes an electromagnetic vibration gear bending fatigue test bench to achieve real-time measurement of root stress during the test and to heat or cool the gears during the test, thereby solving the problems existing in the prior art. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention proposes an electromagnetic vibration gear bending fatigue test bench, which leads out a row of elastic wires at the vibration connecting plate, and a strain gauge is connected to the end of each wire. After the gear is installed, the strain gauge is directly attached to the dangerous section of the tooth root, so as to realize real-time monitoring and dynamic recording of the tooth root stress during the test, avoid the calculation error caused by analytical calculation, and improve the accuracy of the test results.

[0005] In order to solve the above-mentioned problems, the present invention proposes the following technical solutions:

[0006] The present invention comprises a variable mass excitation system, an electromagnetic resonance system, a servo motor and a base; the variable mass excitation system is fixedly placed on the upper end of the electromagnetic vibration system, the lower end of the electromagnetic vibration system passes through the upper connecting plate and is connected to the middle part of the vibration connecting plate, the two sides of the variable mass excitation system are respectively connected to the upper ends of two connecting springs, the lower ends of the two connecting springs pass through the upper connecting plate and are connected to the two sides of the vibration connecting plate, both sides of the top surface of the vibration connecting plate are connected to the bottom surface of the upper connecting plate through preloaded springs; a force sensor is fixedly installed on the lower end surface of the vibration connecting plate, the probe end of the force sensor faces downward and is fixed with an upper loading unit, and a measuring system is simultaneously connected and installed on the lower end surface of the vibration connecting plate, the measuring system comprises a plurality of strain components, each strain component comprises an elastic line and a strain gauge, and the upper end of the elastic line is fixedly connected to the lower end surface of the vibration connecting plate , a strain gauge is fixedly connected to the lower end of the elastic line, and the strain gauge is attached to the test gear; the working platform is fixedly installed on the top of the base, and the base is fixed to the foundation through a grounding spring coupling, and a lower loading unit is fixed on the top surface of the working platform, and the lower loading unit is located directly below the upper loading unit, and an environmental chamber is installed and connected between the lower loading unit and the upper loading unit; the upper end of the lower loading unit and the lower end of the upper loading unit are both extended into the environmental chamber and connected to the test gear in the environmental chamber, and a lower connecting plate, a ball screw, a servo motor and a reducer are installed in the base, and both sides of the bottom of the upper connecting plate are fixedly connected to both sides of the top of the lower connecting plate through a guide rod that is movably passed through the working platform, and the ball screw is arranged vertically and the middle part is threadedly sleeved in the threaded hole in the middle part of the lower connecting plate to form a screw nut pair, and the lower end of the ball screw is connected to the servo motor through the reducer.

[0007] The test gear is installed on a gear bracket and is located in an environmental chamber. The test gear can move up and down and rotate relative to the gear bracket. The gear bracket is installed on a working platform.

[0008] The strain gauge is fixedly attached to the side surface of the test gear at the tooth root, and the edges of the upper loading unit and the lower loading unit are both tightly attached to the side surface of the test gear at the tooth top.

[0009] The variable mass excitation system is mainly composed of four mass blocks fixedly installed vertically.

[0010] The reducer is mainly composed of a worm wheel, a worm and a housing. The worm wheel is coaxially installed at the lower end of the ball screw. The worm wheel and the worm are meshed, and the worm is connected to the output end of the servo motor.

[0011] The reducer and the servo motor are made into an integrated body, and the worm and the output shaft of the servo motor are a whole.

[0012] The environmental chamber is mainly composed of a chamber body and a heater, a cooling tube and a temperature sensor installed on the chamber body. The heater, the cooling tube and the temperature sensor are all installed on the inner side of the chamber body.

[0013] The present invention designs a stable, reliable and effective electromagnetic vibration structure, and combines it with the gear bending fatigue test to achieve a stable and excellent gear bending fatigue test.

[0014] The beneficial effects of the present invention are:

[0015] The present invention is a floating workbench, which can effectively isolate the influence of environmental vibration sources on equipment, and the influence of equipment on the surrounding environment.

[0016] The present invention realizes loading of the sample through electromagnetic vibration. The measuring system is provided with strain gauges. The tooth root stress and loading frequency can be monitored in real time. The damage of the gear tooth root can be judged by the changes of the tooth root stress and the vibration frequency. When the gear tooth is broken, the machine can be automatically shut down.

[0017] The present invention places the gear in an environmental box, the temperature box contains lubricating oil with a certain liquid level, the gear is immersed in the lubricating oil, the lubricating oil can be heated and cooled by a heater and a cooling pipe, and the gear is indirectly heated or cooled to achieve a bending fatigue test at a specific ambient temperature.

[0018] The present invention conducts tests through the principle of resonance, and a higher test frequency can quickly obtain the bending fatigue strength of the gear sample, thereby reducing the development cycle.

[0019] The present invention is provided with a variable mass excitation system and fixedly placed on the upper end of the electromagnetic vibration system. The variable mass excitation system is composed of a plurality of mass blocks vertically fixed together. The resonant frequency during the test can be changed by disassembling and assembling the mass blocks to achieve loading requirements of different frequencies.

[0020] The present invention installs the test gear on the gear bracket, and the test gear can move up and down and rotate relative to the gear bracket, so that the gear sample can be quickly replaced and can meet the test of gears of different specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the gear installation of the present invention;

[0023] Figure 3 This is a schematic diagram of the installation of the strain gauge of the present invention;

[0024] Figure 4 It is a schematic diagram of the transmission parts of the reducer of the present invention.

[0025] Among them: 1. variable mass excitation system; 2. electromagnetic resonance system; 3. connecting spring; 4. upper connecting plate; 5. preload spring; 6. vibration connecting plate; 7. upper loading unit; 8. lower loading unit; 9. guide rod; 10. working platform; 11. lower connecting plate; 12. ball screw; 13. reducer; 14. servo motor; 15. grounding spring; 16. base; 17. worm; 18. worm wheel; 19. environmental chamber; 20. test gear; 21. strain gauge; 22. elastic line; 23. force sensor; 24. measurement system; 25. gear bracket; 26. heater; 27. cooling pipe; 28. temperature sensor. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific implementations.

[0027] like Figure 1 As shown, the test bench specifically implemented includes a variable mass excitation system 1, an electromagnetic resonance system 2, a servo motor 14 and a base 16; the variable mass excitation system 1 is fixedly placed on the upper end of the electromagnetic vibration system 2, and the lower end of the electromagnetic vibration system 2 passes through the upper connecting plate 4 and is connected to the middle part of the vibration connecting plate 6. In the specific implementation, the bottom surface of the middle part of the variable mass excitation system 1 is connected to the electromagnetic vibration system 2 by bolts, and the two sides of the variable mass excitation system 1 are respectively connected to the upper ends of two connecting springs 3, and the lower ends of the two connecting springs 3 pass through the upper connecting plate 4 and are connected to the two sides of the vibration connecting plate 6. Both sides of the top surface of the vibration connecting plate 6 are connected to the bottom surface of the upper connecting plate 4 through preloaded springs 5; in this way, the variable mass excitation system 1 is coupled and connected to the vibration connecting plate 6 through a group of connecting springs 3, and the vibration connecting plate 6 is coupled and connected to the upper connecting plate 4 through the preloaded springs 5, and the force generated by the electromagnetic resonance system 2 is transmitted to the vibration connecting plate 4 through the variable mass system 1 and the connecting springs 3. The variable mass excitation system 1 and the vibration connecting plate 6 are connected together through the electromagnetic vibration system 2 and two connecting springs 3 to form an overall electromagnetic vibration structure, and the overall electromagnetic vibration structure is elastically floatingly connected to the upper connecting plate 4 through the preload spring 5.

[0028] A force sensor 23 is fixedly installed on the lower end surface of the vibration connecting plate 6, and the probe end of the force sensor 23 faces downward and is fixed with the upper loading unit 7. A measuring system 24 is also connected and installed on the lower end surface of the vibration connecting plate 6. The measuring system 24 includes multiple groups of strain components, each strain component includes an elastic line 22 and a strain gauge 21 connected to the end of the elastic line 22. The upper end of the elastic line 22 is fixedly connected to the lower end surface of the vibration connecting plate 6, and the lower end of the elastic line 22 is fixedly connected to the strain gauge 21. During the test, the strain gauge 21 is cast and glued to the test gear 20.

[0029] The working platform 10 is fixedly mounted on the top of the base 16, and the base 16 is coupled and fixed to the foundation through a group of grounding springs 15. A lower loading unit 8 is fixed on the top surface of the working platform 10, and the lower loading unit 8 is located directly below the upper loading unit 7; the base 16 is hollow inside, and a lower connecting plate 11, a ball screw 12, a servo motor 14 and a reducer 13 are installed in the base 16. Both sides of the bottom of the upper connecting plate 4 are fixedly connected by a guide rod 9 that movably passes through the working platform 10 and the two sides of the top of the lower connecting plate 11. The lower end of the guide rod 9 passes through the guide hole on the working platform 10 and is connected to the lower connecting plate 11. The upper and lower ends of the ball screw 12 are respectively installed on the working platform 10 and in the base 16 through bearings. The ball screw 12 is arranged and installed vertically and the middle part is threadedly sleeved in the threaded hole in the middle of the lower connecting plate 11 to form a screw nut pair. The lower end of the ball screw 12 is connected to the servo motor 14 through the reducer 13, and the reducer 13 and the servo motor 14 are both installed on the base 16. The reducer 13 and the servo motor 14 are made into an integrated body, and the worm 17 and the output shaft of the servo motor 14 are integrated into one body.

[0030] The servo motor 14 drives the ball screw 12 to rotate through the reducer 13, and then drives the upper connecting plate 4 and the lower connecting plate 11 to move up and down under the guidance of the guide rod 9 through the screw nut pair, and then drives the upper loading unit 7 connected to the vibration connecting plate 6 on the upper connecting plate 4 to move up and down, adjusts the distance between the upper loading unit 7 and the lower loading unit 8, and makes the upper loading unit 7 move up and down close to or away from the lower loading unit 8.

[0031] like Figure 2 As shown, the test gear 20 is mounted on a gear bracket 25 . The test gear 20 can move up and down and rotate relative to the gear bracket 25 . The gear bracket 25 is mounted on the working platform 10 .

[0032] like Figure 3 As shown, the strain gauge 21 is fixedly attached to the side surface of the tooth root of the test gear 20. Specifically, after the gear is installed, the strain gauge is directly attached to the dangerous section of the tooth root. The test gear 20 is located on one side between the upper loading unit 7 and the lower loading unit 8, and the edges of the upper loading unit 7 and the lower loading unit 8 are both tightly attached to the side surface of the tooth top of the test gear 20.

[0033] The variable mass excitation system 1 mainly consists of four mass blocks which are vertically fixed together, and the mass of the variable mass excitation system 1 can be changed by disassembling and assembling the mass blocks.

[0034] like Figure 4 As shown, the reducer 13 is mainly composed of a worm wheel 18 , a worm 17 and a housing. The worm wheel 18 is coaxially mounted on the lower end of the ball screw 12 . The worm wheel 18 and the worm 17 are meshed with each other. The worm 17 is connected to the output end of the servo motor 14 .

[0035] The working process of the electromagnetic vibration gear bending fatigue test device of the present invention is as follows:

[0036] The test gear 20 has different sizes. The upper loading unit 7 is driven by the servo motor 14 to move up and down, so that the spacing between the upper loading unit 7 and the lower loading unit 8 matches the size of the test gear 20, and the edges of the upper loading unit 7 and the lower loading unit 8 are tightly attached to the top side surfaces of the upper and lower side teeth of the test gear 20.

[0037] The test gear 20 is placed in an environmental box 19, which is filled with a certain level of lubricating oil. The test gear 20 is immersed in the lubricating oil. The lubricating oil can be heated or cooled by a heater 26 and a cooling pipe 27 to provide a specific test temperature. The test temperature can be monitored by a temperature sensor 28. When there is no special test temperature requirement, the lubricating oil is removed and the heater 26 and the cooling pipe 27 are turned off.

[0038] The pressure is detected in real time by the force sensor 23 to obtain the feedback force, and the feedback force is used to feedback control the servo motor 14 to drive the adjustment of the distance between the upper loading unit 7 and the lower loading unit 8, so that the contact pressure between the edges of the upper loading unit 7 and the lower loading unit 8 and the surface of the test gear 20 is within a preset range.

[0039] The strain gauge 21 is then stretched by the elastic wire 22 and fixed with glue to the root side surface of the same tooth on the top side surface of the tooth to which the edge of the upper loading unit 7 is closely attached. The strain gauges 21 of multiple strain assemblies are arranged along the axial direction of the test gear 20, that is, along the root of the tooth.

[0040] Turn on the electromagnetic resonance system 2. Under the fixed variable mass excitation system 1, the electromagnetic resonance system 2 vibrates at a small frequency. After being transmitted to the upper loading unit 7 through the vibration connecting plate 6 and the force sensor 23, the test gear 20 is driven to perform bending fatigue vibration. Under the operation control of the electromagnetic resonance system 2, the test gear 20 is gradually driven to vibrate at the resonance frequency.

[0041] The resonance frequency is obtained by real-time detection through the electromagnetic resonance system 2, and the stress on the tooth root surface of the test gear 20 is detected in real time through the strain gauge 21; the test is continuously performed until the test gear 20 fails, and the fatigue test parameters are obtained.

[0042] A bending fatigue test relationship model is established between the resonance frequency, stress and fatigue test parameters. The test gear 20 to be tested is tested through the relationship model to obtain accurate fatigue test parameter results of the test gear 20, and the fatigue damage of the test gear is obtained, thereby avoiding the calculation error caused by analytical calculation and improving the accuracy of the test results. In the specific implementation, the fatigue test parameters are measured by the number of cycles.

[0043] By changing the applied mass of the variable mass excitation system 1 and performing repeated test steps under different masses of the variable mass excitation system 1, a more series of test data of resonance frequency, stress and fatigue test parameters can be obtained, and then the bending fatigue test relationship model under different mass influences can be obtained, so as to achieve accurate measurement results in a wider range of application scenarios and improve the validity of the test results.

[0044] When there are special requirements for the test environment, the test gear is heated or cooled through the environmental chamber 19 to obtain a series of fatigue test data under high or low temperature conditions, and then the bending fatigue test relationship model under different test temperatures is obtained to realize the application of fatigue data under multiple environmental conditions.

Claims

1. An electromagnetic vibration gear bending fatigue test bench, characterized in that: The invention comprises a variable mass excitation system (1), an electromagnetic resonance system (2), a servo motor (14) and a base (16); the variable mass excitation system (1) is fixedly placed on the upper end of the electromagnetic vibration system (2); the lower end of the electromagnetic vibration system (2) passes through an upper connection plate (4) and is connected to the middle of a vibration connection plate (6); both sides of the variable mass excitation system (1) are respectively connected to the upper ends of two connection springs (3); the lower ends of the two connection springs (3) pass through the upper connection plate (4) and are connected to both sides of the vibration connection plate (6); both sides of the top surface of the vibration connection plate (6) are connected by The preload spring (5) is connected to the bottom surface of the upper connecting plate (4); a force sensor (23) is fixedly installed on the lower end surface of the vibration connecting plate (6); the probe end of the force sensor (23) faces downward and is fixed with an upper loading unit (7); a measuring system (24) is also connected and installed on the lower end surface of the vibration connecting plate (6); the measuring system (24) includes a plurality of strain components, each strain component includes an elastic line (22) and a strain gauge (21); the upper end of the elastic line (22) is fixedly connected to the lower end surface of the vibration connecting plate (6); and the lower end of the elastic line (22) is fixedly connected to the strain gauge (21). ), the strain gauge (21) is attached to the test gear (20); the working platform (10) is fixedly mounted on the top of the base (16), the base (16) is fixed to the foundation through coupling with the grounding spring (15), the top surface of the working platform (10) is fixed with a lower loading unit (8), the lower loading unit (8) is located directly below the upper loading unit (7), and an environmental chamber (19) is installed and connected between the lower loading unit (8) and the upper loading unit (7); the upper end of the lower loading unit (8) and the lower end of the upper loading unit (7) are both extended into the environmental chamber (19) and connected to the environmental chamber (19) ), a lower connecting plate (11), a ball screw (12), a servo motor (14) and a reducer (13) are installed in the base (16), both sides of the bottom of the upper connecting plate (4) are fixedly connected by a guide rod (9) movably passing through the working platform (10) and the two sides of the top of the lower connecting plate (11), the ball screw (12) is arranged vertically and the middle part is threadedly sleeved in the threaded hole in the middle part of the lower connecting plate (11) to form a screw nut pair, and the lower end of the ball screw (12) is connected to the servo motor (14) through the reducer (13).

2. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The test gear (20) is mounted on a gear bracket (25) and is located in an environmental chamber (19). The test gear (20) can move up and down and rotate relative to the gear bracket (25). The gear bracket (25) is mounted on a working platform (10).

3. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The strain gauge (21) is fixedly attached to the side surface of the tooth root of the test gear (20), and the edges of the upper loading unit (7) and the lower loading unit (8) are both tightly attached to the side surface of the tooth top of the test gear (20).

4. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The variable mass excitation system (1) is mainly composed of four mass blocks fixed together vertically.

5. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The reducer (13) is mainly composed of a worm wheel (18), a worm (17) and a housing. The worm wheel (18) is coaxially mounted on the lower end of the ball screw (12). The worm wheel (18) and the worm (17) are meshed with each other. The worm (17) is connected to the output end of the servo motor (14).

6. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The reducer (13) and the servo motor (14) are made into an integrated form, and the worm (17) and the output shaft of the servo motor (14) are integrated into one body.

7. The electromagnetic vibration gear bending fatigue test bench according to claim 1, characterized in that: The environmental chamber (19) is mainly composed of a chamber body and a heater (26), a cooling pipe (27), and a temperature sensor (28) installed on the chamber body. The heater (26), the cooling pipe (27), and the temperature sensor (28) are all installed on the inner side of the chamber body.

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