Fatigue test device for orbital transfer crank

Abstract

The invention belongs to the technical field of test devices, and particularly relates to an orbital transfer crank fatigue test device which comprises a main shaft motor and an auxiliary shaft motor, a main shaft gear is arranged on a rotating shaft of the main shaft motor and is in transmission connection with a main eccentric wheel gear, an eccentric hole is formed in a main eccentric wheel, and an auxiliary eccentric wheel is rotationally arranged in the eccentric hole. An auxiliary shaft gear is arranged on a rotating shaft of the auxiliary shaft motor and is in transmission connection with a central shaft gear on one side of the auxiliary eccentric wheel; an eccentric shaft on the other side of the auxiliary eccentric wheel is rotatably connected with a connecting rod, the other end of the connecting rod is rotatably connected with a sliding rod, the sliding rod is slidably arranged, the other end of the sliding rod is used for being connected with a testing part, and the other end of the testing part is fixedly arranged during testing. Compared with a traditional reducing mechanism, the device does not need to use a slip ring, has a larger dynamic amplitude modulation range and a higher response speed, and can meet the requirements of various fatigue test conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of test devices, and particularly relates to a variable-rail crank fatigue test device. Background Art

[0002] A fatigue testing machine is an important device for studying the fatigue characteristics of materials, components and devices under cyclic loads, and is widely used in fields such as aerospace, automobile manufacturing and basic materials science. Existing fatigue testing machines are mainly divided into two categories: strain control and stress control. Among them, strain-controlled fatigue testing machines are usually used for constant amplitude testing, while stress-controlled fatigue testing machines are suitable for variable amplitude testing. However, most current fatigue testing machines have the following limitations when performing variable amplitude testing: First, at higher frequencies, the working amplitude of the testing machine will be greatly attenuated, making it difficult to meet the testing requirements of high frequency and large amplitude; Second, the amplitude of traditional testing machines usually depends on hydraulic drive, electric drive or electromagnetic drive for adjustment, but these methods have problems such as complex structure, limited amplitude adjustment range and slow response speed, and cannot meet the requirements of some special fatigue tests. In addition, during the working process, it is often difficult to adjust the amplitude of the testing machine in real time, and the existing real-time adjustment amplitude is small and cannot be adjusted in a large range, seriously limiting its adaptability and experimental accuracy under complex working conditions.

[0003] Due to its unique kinematic characteristics, the crank-slider mechanism provides new possibilities for the amplitude adjustment of fatigue testing machines. By adjusting the crank length, the movement amplitude of the slider can be flexibly changed to achieve relatively precise amplitude control. Compared with traditional hydraulic, electric or electromagnetic drive methods, the crank-slider mechanism has the advantages of simple structure, easy amplitude control and high efficiency. However, the existing amplitude adjustment schemes based on the crank-slider mechanism still have limitations.

[0004] The Chinese patent with the authorized announcement number CN221549983U discloses a fatigue testing machine and its driving mechanism, including an extrusion mechanism, an eccentric mechanism, a transmission mechanism and an upper plate position adjustment mechanism. This invention drives the transmission wheel and / or the eccentric shaft to move along the axis of the rotating shaft through the eccentric distance adjustment mechanism to change the axial relative position between the transmission wheel and the eccentric shaft, thereby realizing the adjustment of the eccentric distance. This adjustment method improves the flexibility of amplitude control to a certain extent, enabling the testing machine to adapt to different testing requirements. However, the adjustment range of this invention is relatively small and cannot meet the requirements of large amplitude adjustment, limiting its applicability in high amplitude or large range adjustable vibration tests. Summary of the Invention

[0005] To solve the above technical problems of the small amplitude adjustment range and difficult real-time adjustment of the fatigue testing machine, the invention provides a variable-rail crank fatigue test device.

[0006] The object of the present invention is achieved by the following technical solutions. A variable orbit crank fatigue test device proposed according to the present invention includes a main shaft motor and a secondary shaft motor. A main shaft gear is arranged on the rotating shaft of the main shaft motor, and the main shaft gear is in gear transmission connection with a main eccentric wheel gear. An eccentric hole is provided on the main eccentric wheel, and a secondary eccentric wheel is rotatably arranged in the eccentric hole. A secondary shaft gear is arranged on the rotating shaft of the secondary shaft motor, and the secondary shaft gear is in gear transmission connection with a central shaft gear on one side of the secondary eccentric wheel; an eccentric shaft on the other side of the secondary eccentric wheel is rotatably connected to a connecting rod, and the other end of the connecting rod is rotatably connected to a sliding rod. The sliding rod is slidably arranged and the other end of the sliding rod is used for connecting with a test component, and the other end of the test component is fixedly arranged during the test.

[0007] Further, the main shaft motor is arranged on a positioning plate through a main shaft motor bracket. The rotating shaft of the main shaft motor is connected to the main shaft through a main shaft elastic coupling, and the main shaft gear is arranged on the main shaft; the secondary shaft motor is arranged on the positioning plate through a secondary shaft motor bracket. The rotating shaft of the secondary shaft motor is connected to the secondary shaft through a secondary shaft elastic coupling, and the secondary shaft gear is arranged on the secondary shaft.

[0008] Further, the main shaft is rotatably arranged on the positioning plate through a main shaft bearing seat group, and the main shaft bearing seat group is arranged on the positioning plate through a corresponding heightening sleeve so that the central horizontal plane of the main shaft is aligned with the central horizontal plane of the main eccentric wheel; the secondary shaft is rotatably arranged on the positioning plate through a secondary shaft bearing seat group, and the secondary shaft bearing seat group is arranged on the positioning plate through a corresponding heightening sleeve so that the axis of the secondary shaft coincides with the axis of the main eccentric wheel.

[0009] Further, a main eccentric wheel gear for meshing with the main shaft gear is arranged on the outer ring of the main eccentric wheel. A rotating bearing is also arranged on the outer ring of the main eccentric wheel. The inner ring of the rotating bearing is sleeved and fixed on the outer ring of the main eccentric wheel, and the outer ring of the rotating bearing is nested and fixed on the main eccentric wheel bracket, so that the main eccentric wheel is rotatably arranged on the main eccentric wheel bracket, and the main eccentric wheel bracket is arranged on the positioning plate.

[0010] Further, the sliding rod is slidably arranged on a linear bearing, and the linear bearing is arranged on the positioning plate through a linear bearing fixing seat. The linear bearing fixing seat is arranged on the positioning plate through a corresponding heightening sleeve so that the central horizontal plane of the sliding rod is aligned with the central horizontal plane of the main eccentric wheel.

[0011] Further, the other end of the test component is arranged on a T-shaped shaft seat, and the T-shaped shaft seat is arranged on the positioning plate through a corresponding heightening sleeve so that both ends of the test component are at the same height.

[0012] Further, both ends of the test component are fixed on corresponding cylindrical pins. A expansion sleeve for fixing the corresponding cylindrical pin is arranged at the other end of the sliding rod, and an intermediate hole for fixing the corresponding cylindrical pin is arranged on the T-shaped shaft seat.

[0013] Further, the T-shaped shaft seat is slidably disposed on the positioning plate, and the sliding direction is parallel to the sliding direction of the sliding rod. After adjusting the position of the T-shaped shaft seat according to the length of the test component, the T-shaped shaft seat can be fixed on the positioning plate.

[0014] Further, an eccentric wheel gear for meshing with the secondary shaft gear is provided on the central shaft of the secondary eccentric wheel.

[0015] Further, both ends of the connecting rod are respectively rotatably connected to the eccentric shaft and the sliding rod through bushings. The bushing of the connecting rod connected to the sliding rod is provided with a pin shaft, and the pin shaft is arranged on the sliding rod.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The present invention aims to provide a fatigue test device with real-time adjustable amplitude to overcome the limitations of existing testing machines in amplitude adjustment. The device ingeniously combines the efficient transmission characteristics of the planetary gear mechanism and the crank-slider mechanism, and has significant advantages such as a compact structure, flexible adjustment, and strong adaptability. Compared with the traditional variable-diameter mechanism, the device does not require a slip ring, and at the same time has a larger dynamic amplitude adjustment range and a higher response speed, and can meet the requirements of various fatigue test conditions. The test device provides reliable experimental equipment support for the study of the fatigue characteristics of materials, components, and devices under complex working conditions.

[0018] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. In order to make the purpose, features, and advantages of the present invention more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a three-dimensional schematic diagram of an embodiment of a variable-rail crank fatigue test device of the present invention;

[0020] Figure 2 is a three-dimensional schematic diagram of another perspective of an embodiment of a variable-rail crank fatigue test device of the present invention;

[0021] Figure 3 is Figure 2 an enlarged schematic diagram of the connection position between the secondary shaft motor and the secondary shaft in

[0022] Reference numerals:

[0023] 1. Spindle motor; 2. Spindle motor bracket; 3. Spindle elastic coupling; 4. Spindle; 5. Spindle gear; 6. Spindle bearing block group; 7. Countershaft motor; 8. Countershaft motor bracket; 9. Sub-eccentric wheel; 10. Main eccentric wheel; 11. Main eccentric wheel bracket; 12. Bush; 13. Connecting rod; 14. Slide bar; 15. Pin shaft; 16. Linear bearing fixed seat; 17. Linear bearing; 18. Expansion sleeve; 19. Cylindrical pin; 20. Test spring; 21. T-shaped shaft seat; 22. Thin-wall bearing; 23. Eccentric wheel gear; 24. Countershaft gear; 25. Countershaft elastic coupling; 26. Countershaft; 27. Countershaft bearing block group; 28. 60mm heightening sleeve; 29. 50mm heightening sleeve; 30. 30mm heightening sleeve; 31. Positioning plate; 32. Aluminum profile. Detailed implementation manners

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] An embodiment of a variable-rail crank fatigue test device of the present invention is as Figures 1 to 3 shown, hereinafter referred to as the device. The device includes a horizontally arranged positioning plate 31, and the various components arranged on the upper part of the positioning plate 31 are positioned with the positioning plate 31 as the reference. The positioning plate 31 is fixed to the aluminum profile 32 by bolts, and all the components connected to the positioning plate 31 are also installed by bolts and nuts. The four corners of the positioning plate 31 are stably supported horizontally through the aluminum profile 32.

[0026] A spindle motor bracket 2 is arranged on the positioning plate 31, a spindle motor 1 is installed on the spindle motor bracket 2, the rotating shaft of the spindle motor 1 is connected to the spindle 4 through a spindle elastic coupling 3. The spindle elastic coupling 3 can absorb shock and buffer, protect other components, and can also compensate for deviations (deviations generated during the manufacturing, installation, and use of each component). Therefore, this design can effectively reduce the installation error and improve the transmission accuracy of the device.

[0027] A shrink disc is sleeved on the main shaft 4, and a main shaft gear 5 is sleeved on the shrink disc. The main shaft gear 5 is fixed on the main shaft 4 through the shrink disc inside it. At both ends of the main shaft 4, a main shaft bearing seat group 6 is provided. The main shaft bearing seat group 6 is arranged on the positioning plate 31 to provide a simply supported beam type rotational support. The rotation of the main shaft motor 1 can drive the rotation of the main shaft 4. In order to ensure that the central horizontal plane of the main shaft 4 is aligned with the central horizontal plane of the main eccentric wheel 10, a 30 mm heightening sleeve 30 is added below the main shaft bearing seat group 6. The 30 mm heightening sleeve 30 is arranged on the positioning plate 31, so as to achieve precise centering installation. In other embodiments, the height dimension of the heightening sleeve can be adjusted according to the specific structural dimensions of the device.

[0028] The main shaft gear 5 and the main eccentric wheel 10 are meshed and connected through gear transmission. Specifically, a main eccentric wheel gear meshing with the main shaft gear 5 is sleeved and fixed on the outer ring of the main eccentric wheel 10. Or, in other embodiments, the main eccentric wheel gear is integrally arranged with the main eccentric wheel 10, that is, teeth are arranged on the outer circumferential wall of the main eccentric wheel 10; A thin-walled bearing 22 is also installed on the outer ring of the main eccentric wheel 10. The thin-walled bearing 22 is installed in cooperation with the main eccentric wheel bracket 11 to provide a smooth rotational support. In other embodiments, the thin-walled bearing 22 can also be replaced with other forms of ordinary rotational bearings. The thin-walled bearing 22 and the main eccentric wheel gear are axially distributed on the outer ring of the main eccentric wheel 10. The inner ring of the thin-walled bearing 22 is sleeved and fixed on the main eccentric wheel 10, and the outer ring is nested and fixed on the main eccentric wheel bracket 11, so as to rotatably arrange the main eccentric wheel 10 on the main eccentric wheel bracket 11. The rotation of the main shaft gear 5 can drive the rotation of the main eccentric wheel 10. The main eccentric wheel bracket 11 is arranged on the positioning plate 31. The main eccentric wheel bracket 11 is provided with set screw holes. The set screws are screwed through the main eccentric wheel bracket 11 and pressed against the outer ring of the thin-walled bearing 22 to lock the thin-walled bearing 22, so as to improve the installation stability and reduce the risk of loosening caused by vibration.

[0029] The main eccentric wheel 10 is provided with an eccentric hole, and the sub-eccentric wheel 9 is installed in the eccentric hole. In this embodiment, the distance between the center of the sub-eccentric wheel 9 and the center of the main eccentric wheel 10 is 20 mm. The sub-eccentric wheel 9 can rotate freely in the eccentric hole to achieve dynamic amplitude modulation.

[0030] The positioning plate 31 is also provided with a sub-shaft motor bracket 8. The sub-shaft motor bracket 8 installs the sub-shaft motor 7 through bolts and nuts. The rotating shaft of the sub-shaft motor 7 is connected to the sub-shaft 26 through a sub-shaft elastic coupling 25; The sub-shaft 26 is provided with a rotational support by a sub-shaft bearing seat group 27. The sub-shaft bearing seat group 27 is arranged on the positioning plate 31. In this embodiment, the sub-shaft bearing seat group 27 is arranged on the positioning plate 31 through its corresponding heightening sleeve, so that the axis of the sub-shaft 26 coincides with the axis of the main eccentric wheel 10.

[0031] The end of the secondary shaft 26 is equipped with a secondary shaft gear 24, which is fixed by a set screw. The secondary shaft gear 24 meshes with the eccentric wheel gear 23 to form a power transmission structure. The eccentric wheel gear 23 is also fixed on the central axis of one side of the secondary eccentric wheel 9 by a set screw. When the secondary shaft motor 7 rotates, it drives the secondary shaft gear 24 to rotate, thereby driving the eccentric wheel gear 23 to rotate and driving the secondary eccentric wheel 9 to rotate within the eccentric hole.

[0032] A bushing 12 is installed on the eccentric shaft on the other side of the secondary eccentric wheel 9. In this embodiment, the axial distance between the eccentric shaft and the central axis on the secondary eccentric wheel 9 is 20 mm. When the secondary eccentric wheel 9 rotates, the eccentric shaft can pass through the center of the main eccentric wheel 10.

[0033] A connecting rod 13 is sleeved outside the bushing 12, enabling the connecting rod 13 to rotate around the eccentric shaft on the secondary eccentric wheel 9 through the bushing 12. The other end of the connecting rod 13 is also installed with a bushing 12, and a pin shaft 15 is inserted into the bushing 12, forming a stable hinged connection between the pin shaft 15 and the connecting rod 13. The pin shaft 15 is passed through the slide bar 14, thereby connecting the connecting rod 13 and the slide bar 14 to form a revolute pair.

[0034] The slide bar 14 cooperates with the linear bearing 17, enabling it to perform reciprocating linear motion within the guiding structure. The linear bearing 17 is installed in the linear bearing fixing seat 16 and is accurately positioned and fixed through the linear bearing fixing seat 16 to ensure the guiding accuracy. In order to ensure that the central horizontal plane of the slide bar 14 is aligned with the central horizontal plane of the main eccentric wheel 10, a 60-mm heightening sleeve 28 is added below the linear bearing fixing seat 16 to ensure the coaxiality of the entire motion system. In other embodiments, the height dimension of the heightening sleeve can be adjusted according to the specific structural dimensions of the device.

[0035] A tension sleeve 18 is installed at the end of the sliding rod 14 for clamping and fixing the cylindrical pin 19. A T-shaped shaft seat 21 is provided at the end of the device. The T-shaped shaft seat 21 is slidably arranged on the positioning plate 31. The sliding direction of the T-shaped shaft seat 21 is parallel to the sliding direction of the sliding rod 14. The position of the T-shaped shaft seat 21 on the positioning plate 31 can be adjusted according to the length of the test spring 20 and the T-shaped shaft seat 21 can be fixed on the positioning plate 31. Therefore, springs of different models can be tested. The middle hole of the T-shaped shaft seat 21 cooperates with the cylindrical pin 19, and the two side walls of the middle hole clamp and fix the cylindrical pin 19. To ensure the same height of the two cylindrical pins (the cylindrical pin 19 at the end of the sliding rod 14 and the cylindrical pin 19 on the T-shaped shaft seat 21), a 50-mm heightening sleeve 29 is added below the T-shaped shaft seat 21 to ensure that the two cylindrical pins 19 are at the same height. The 50-mm heightening sleeve 29 is slidably arranged on the positioning plate 31. The 50-mm heightening sleeve 29 adjusts its position on the positioning plate 21 according to the length of the test spring 20 and is fixed. In other embodiments, the height dimension of the heightening sleeve can be adjusted according to the specific structural dimensions of the device. The two ends of the test spring 20 are respectively installed on the two cylindrical pins 19 on both sides. Since the two cylindrical pins 19 on both sides have the same height, the two ends of the test spring 20 can have the same height, keeping the test spring 20 in a horizontal state.

[0036] During the amplitude modulation process of the device, the crank length is mainly changed by controlling the relative position adjustment of the main eccentric wheel 10 and the auxiliary eccentric wheel 9, so as to realize the dynamic adjustment of the amplitude of the fatigue test device. The amplitude modulation process includes the main shaft motor 1 driving the main eccentric wheel 10 to rotate and the auxiliary shaft motor 7 driving the auxiliary eccentric wheel 9 to rotate to achieve precise amplitude modulation control.

[0037] When the main shaft motor 1 and the auxiliary shaft motor 7 rotate at a fixed speed ratio (the ratio of the rotational speeds of the main shaft motor 1 and the auxiliary shaft motor 7), the auxiliary shaft motor 7 drives the auxiliary shaft gear 24 to rotate through the auxiliary shaft 26 and is linked with the eccentric wheel gear 23, causing the sub-eccentric wheel 9 to rotate within the eccentric hole of the main eccentric wheel 10; at the same time, the main shaft motor 1 drives the main shaft gear 5 to rotate and drives the main eccentric wheel 10 to rotate through gear transmission. In this case, since the speed ratio of the two motors remains constant, the main eccentric wheel 10 and the sub-eccentric wheel 9 are relatively stationary, that is, the main eccentric wheel 10 and the sub-eccentric wheel 9 can be regarded as a rotating whole. The eccentric shaft on the sub-eccentric wheel 9 rotates around the center of the main eccentric wheel 10, and the distance between the eccentric shaft of the sub-eccentric wheel 9 and the center of the main eccentric wheel 10 is the crank length, so that the crank length can be kept unchanged, which is equivalent to the working mode of the traditional crank-slider mechanism. When the test spring 20 is subjected to a fatigue test by this device, the distance between the eccentric shaft of the sub-eccentric wheel 9 and the center of the main eccentric wheel 10 can be set in advance, that is, the crank length is adjusted, and the test can be carried out after adjusting to the corresponding amplitude. The method of setting the amplitude is as follows: First, start the auxiliary shaft motor 7 to make the sub-eccentric wheel 9 rotate, and then adjust the position of the eccentric shaft on the sub-eccentric wheel 9. The position of the eccentric shaft can be at the center of the main eccentric wheel 10. At this time, the crank length is 0 and the corresponding amplitude is the smallest; it can also be set so that the eccentric shaft is at the position farthest from the center of the main eccentric wheel 10. At this time, the distance between the eccentric shaft and the center of the main eccentric wheel 10 (crank length) is the sum of the distance from the eccentric shaft to the center of the sub-eccentric wheel 9 and the distance from the center of the sub-eccentric wheel 9 to the center of the main eccentric wheel 10, which is 40 mm in this embodiment, and the corresponding amplitude is the largest; or the eccentric shaft is set at the corresponding position between the minimum amplitude and the maximum amplitude. At this time, the crank length is between 0 and 40 mm, and then the main shaft motor 1 and the auxiliary shaft motor 7 are turned on simultaneously and the speed ratio is kept unchanged to carry out the fatigue test at the corresponding amplitude. By adjusting the rotational speeds of the two motors, the vibration frequency can be adjusted.

[0038] During the test, when the speed ratio of the main shaft motor 1 and the auxiliary shaft motor 7 is adjusted to make the speed ratio change continuously, the sub-eccentric wheel 9 rotates relative to the main eccentric wheel 10. The distance between the eccentric shaft on the sub-eccentric wheel 9 and the center of the main eccentric wheel 10 changes as the sub-eccentric wheel 9 rotates relative to the main eccentric wheel 10, resulting in a change in the crank length, thereby changing the motion amplitude of the slider (i.e., the slide bar 14 in the present invention) and achieving dynamic amplitude adjustment. When the speed ratio of the two motors returns to being constant again, the crank length is stable and the system re-enters the fixed amplitude mode. In this way, the fatigue test device can adjust the amplitude in real time and continuously during the working process to meet the requirements of different fatigue tests.

[0039] In summary, the present invention provides a variable-orbital crank fatigue test device, which includes main components such as a main eccentric wheel 10, a sub-eccentric wheel 9, a connecting rod 13, a slide bar 14, etc. These components are mechanically connected to achieve the function of significantly changing the amplitude in real time during the working process.

[0040] In other embodiments, in addition to testing the test spring 20, the device can also test other elastic components or other types of test components.

[0041] The significant advantages of the present invention are summarized as follows:

[0042] 1) No slip ring design; traditional adjustable-amplitude crank mechanisms usually rely on slip rings for connection, and slip rings have contact wear problems during long-term operation. At the same time, the design of slip rings is limited by rotational speed and it is difficult to meet the requirements of high-frequency fatigue tests; while this device adopts a main eccentric wheel - sub-eccentric wheel linkage structure, eliminating the problems brought by slip ring wear and rotational speed limitation.

[0043] 2) Compact structure; the device mainly uses gears for transmission, making the overall structure more compact and smaller in size, suitable for application scenarios within limited space.

[0044] 3) The amplitude can be continuously and significantly adjusted in real time; traditional amplitude adjustment methods usually require manual adjustment or component replacement, and it is difficult to perform continuous and significant adjustment during the test; this device uses the planetary gear principle to control the relative rotation of the two eccentric wheels, enabling real-time adjustment of the crank length.

[0045] 4) High-precision amplitude control; the present invention can control the servo motor through pulses (both the main shaft motor 1 and the sub-shaft motor 7 of the present invention can use servo motors), enabling precise control of the main eccentric wheel 10 and the sub-eccentric wheel 9, resulting in high-precision changes in the crank length.

[0046] 5) The present invention can achieve continuous amplitude adjustment of the crank length within the range of 0 - 40 mm during the test process (the structural dimensions of the main eccentric wheel and the sub-eccentric wheel can be designed according to needs, and then the amplitude adjustment range can be designed), reducing the dependence on additional transmission systems, thereby significantly improving the applicability of the test device.

[0047] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A crankshaft fatigue test device, comprising a main shaft motor (1) and a secondary shaft motor (7), characterized in that: A main shaft gear (5) is arranged on the rotating shaft of the main shaft motor (1), and the main shaft gear (5) is gear-connected with the main eccentric wheel (10). An eccentric hole is arranged on the main eccentric wheel (10), and a secondary eccentric wheel (9) is rotatably arranged in the eccentric hole. A secondary shaft gear (24) is arranged on the rotating shaft of the secondary shaft motor (7), and the secondary shaft gear (24) is gear-connected with the central shaft on one side of the secondary eccentric wheel (9); the eccentric shaft on the other side of the secondary eccentric wheel (9) is rotatably connected with the connecting rod (13), and the other end of the connecting rod (13) is rotatably connected with the sliding rod (14), the sliding rod (14) is slidably arranged, and the other end of the sliding rod (14) is used to connect with the test component, and the other end of the test component is fixedly arranged during testing.

2. A track change crank fatigue test device according to claim 1, characterized in that: The main shaft motor (1) is arranged on the positioning plate (31) through the main shaft motor bracket (2), the rotating shaft of the main shaft motor (1) is connected to the main shaft (4) through the main shaft elastic coupling (3), and the main shaft gear (5) is arranged on the main shaft (4); the secondary shaft motor (7) is arranged on the positioning plate (31) through the secondary shaft motor bracket (8), the rotating shaft of the secondary shaft motor (7) is connected to the secondary shaft (26) through the secondary shaft elastic coupling (25), and the secondary shaft gear (24) is arranged on the secondary shaft (26).

3. A track change crank fatigue test device according to claim 2, characterized in that: The main shaft (4) is rotatably arranged on the positioning plate (31) through a main shaft bearing seat group (6), and the main shaft bearing seat group (6) is arranged on the positioning plate (31) through a corresponding cushioning sleeve so that the central horizontal plane of the main shaft (4) is aligned with the central horizontal plane of the main eccentric wheel (10); the secondary shaft (26) is rotatably arranged on the positioning plate (31) through a secondary shaft bearing seat group (27), and the secondary shaft bearing seat group (27) is arranged on the positioning plate (31) through a corresponding cushioning sleeve so that the axis of the secondary shaft (26) coincides with the axis of the main eccentric wheel (10).

4. A track change crank fatigue test device according to claim 2, characterized in that: The outer ring of the main eccentric wheel (10) is provided as a main eccentric wheel gear for meshing with the main shaft gear (5); the outer ring of the main eccentric wheel (10) is also provided with a rotating bearing; the inner ring of the rotating bearing is sleeved and fixed on the outer ring of the main eccentric wheel (10); the outer ring of the rotating bearing is nested and fixed on the main eccentric wheel bracket (11), so that the main eccentric wheel (10) is rotatably arranged on the main eccentric wheel bracket (11); and the main eccentric wheel bracket (11) is arranged on the positioning plate (31).

5. The track change crank fatigue test device according to claim 2, characterized in that: The slide bar (14) is slidably arranged on a linear bearing (17), the linear bearing (17) is arranged on a positioning plate (31) via a linear bearing fixing seat (16), and the linear bearing fixing seat (16) is arranged on the positioning plate (31) via a corresponding cushioning sleeve so that the central horizontal plane of the slide bar (14) is aligned with the central horizontal plane of the main eccentric wheel (10).

6. A track change crank fatigue test device according to claim 2, characterized in that: The other end of the test component is arranged on a T-shaped shaft seat (21), and the T-shaped shaft seat (21) is arranged on a positioning plate (31) via a corresponding cushioning sleeve so that the two ends of the test component are at the same height.

7. A track change crank fatigue test device according to claim 6, characterized in that: Both ends of the test component are fixed on the corresponding cylindrical pin (19), the other end of the slide rod (14) is provided with a tightening sleeve (18) for fixing the corresponding cylindrical pin (19), and a middle hole for fixing the corresponding cylindrical pin (19) is provided on the T-shaped shaft seat (21).

8. The track change crank fatigue test device according to claim 6, characterized in that: The T-shaped shaft seat (21) is slidably arranged on the positioning plate (31), and the sliding direction is parallel to the sliding direction of the slide rod (14). After the position of the T-shaped shaft seat (21) is adjusted according to the length of the test component, the T-shaped shaft seat (21) can be fixed on the positioning plate (31).

9. The track change crank fatigue test device according to claim 1, characterized in that: An eccentric wheel gear (23) for meshing with a countershaft gear (24) is arranged on the central axis of the secondary eccentric wheel (9).

10. The track change crank fatigue test device according to claim 1, characterized in that: The two ends of the connecting rod (13) are rotatably connected to the eccentric shaft and the sliding rod (14) through a shaft sleeve (12), and a pin shaft (15) is passed through the shaft sleeve (12) connecting the connecting rod (13) and the sliding rod (14), and the pin shaft (15) is passed through the sliding rod (14).

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