A motorcycle frame fatigue test device

Abstract

The present application relates to the technical field of vehicle parts testing, in particular to a motorcycle frame fatigue test device, which comprises a test platform and an excitation mechanism arranged thereon, the excitation mechanism comprising a transmission mechanism and two synchronously rotating rotary cams. A front wheel and a rear wheel are assembled on the frame body. In the test state, the front wheel and the rear wheel are respectively lapped down on the two rotary cams, and the frame is vibrated up and down by the rotary cam to establish a highly realistic road bump stress model. In addition, the frame bearing bottom plate is connected with a front counterweight for simulating the load of an oil tank, the front counterweight is connected with a limiting slide, and the limiting slide is connected with the test platform in the vertical direction. The present application can effectively limit the lateral deviation and prevent the frame from rolling over without interfering with the free jumping of the frame up and down with the excitation force, thereby improving the accuracy of the fatigue data and ensuring the safety and stability of the high-strength continuous test.

Description

Technical Field

[0001] This invention relates to the field of vehicle component testing technology, specifically to a motorcycle frame fatigue testing device. Background Technology

[0002] As the core load-bearing skeleton of the entire motorcycle, the structural strength and fatigue life of the motorcycle frame directly affect the safety of the rider. Therefore, rigorous dynamic fatigue testing must be conducted on it during the product development stage. However, existing motorcycle frame fatigue testing equipment still has the following shortcomings in practical applications: Firstly, in terms of dynamic operating condition simulation, traditional fatigue testing benches typically rigidly anchor a few mounting points of the frame directly to the actuators, subjecting them to harsh unidirectional tension and compression. This fixing method ignores the actual state of a motorcycle riding on a real road, where road bumps are transmitted upwards through the front and rear wheels, alternating stress. It fails to establish a dynamic bump force model of the entire vehicle based on the differential undulation of the front and rear wheels, resulting in a significant deviation between the obtained fatigue test data and real riding conditions.

[0003] Secondly, regarding vehicle weight distribution and test stability, in order to make the test stress closer to the real state, it is usually necessary to add a load simulating the weight of components such as the fuel tank in the bottom plate area in the middle of the frame. However, the motorcycle frame itself has the physical characteristics of "high center of gravity and narrow chassis". When a central weight is applied and a violent vertical alternating vibration test is carried out, the frame is very prone to losing balance and shifting left and right or even tipping over. This will not only frequently force the test to be interrupted, but also easily cause serious equipment damage or safety accidents.

[0004] To address the aforementioned rollover issue, using conventional multi-dimensional rigid clamps to lock the frame in all directions to prevent lateral displacement would directly restrict the frame's vertical free movement, making alternating vertical vibration tests difficult to conduct smoothly. Therefore, how to simulate the vehicle's counterweight load while allowing the frame to move freely up and down under vibration force, and effectively limiting its lateral tilting, is a pressing technical challenge in this field. Summary of the Invention

[0005] Therefore, it is necessary to provide a motorcycle frame fatigue testing device to address the problems of existing technology.

[0006] To address the problems of existing technologies, the present invention adopts the following technical solution: a motorcycle frame fatigue testing device for conducting fatigue tests on the frame body, wherein the frame body is provided with a steering head tube, a load-bearing base plate, a rear swingarm mounting lug, and a seat mounting bracket, comprising: Test platform, fixed settings; A vibration excitation mechanism is provided on the test platform. The vibration excitation mechanism includes a transmission mechanism and two rotating cams spaced apart in the horizontal direction. The transmission mechanism is used to drive the two rotating cams to rotate synchronously. The test wheel includes a front wheel and a rear wheel, the front wheel and the rear wheel being detachably connected to the steering head tube and the rear swingarm mounting lug, respectively; A front counterweight, detachably connected to the supporting base plate, to simulate the load on the fuel tank; and A limiting slide block is slidably connected to the test platform in the vertical direction, and the limiting slide block is connected to the front counterweight to limit the left and right displacement of the vehicle frame body; In the test state, the front wheel and the rear wheel are respectively attached downwards to the two rotating cams, so that the rotating cams drive the frame body to vibrate up and down.

[0007] Furthermore, a rear counterweight is installed on the seat mounting frame. The rear counterweight includes a flexible bearing pad and several columnar counterweight blocks. The flexible bearing pad is fitted and bound to the seat mounting frame. The upper surface of the flexible bearing pad is provided with several spaced-apart annular fastening straps, and each annular fastening strap is closed by a nylon hook and loop fastener to form a receiving ring. Each columnar counterweight block is horizontally inserted into the corresponding receiving ring.

[0008] Furthermore, the front counterweight is a water tank, the top of the water tank is provided with a water inlet, a sealing cap is screwed onto the water inlet, and a quick-release connector is provided between the water tank and the limiting slide to fix the two together.

[0009] Furthermore, a plurality of first inserts are fixedly provided on the limiting slide, each of the first inserts being vertically arranged and having an elastic contraction opening at one end. A plurality of inserts corresponding one-to-one with the first inserts are fixedly provided at the bottom of the water tank, each insert passing through the bearing base plate and inserted into the corresponding first insert. The number of quick-release connectors is the same as the number of first inserts, and each quick-release connector is a first pipe clamp fitted onto the elastic contraction opening of the first insert.

[0010] Furthermore, a positioning seat is fixedly provided on the test platform, and two symmetrically arranged vertical guide rails are fixedly provided on the top of the positioning seat. A slider is slidably provided in each vertical guide rail. The limiting slide is rotatably connected between the two sliders. A support plate is provided below the limiting slide. A hydraulic cylinder for driving the lifting and lowering of the support plate is fixedly provided in the positioning seat.

[0011] Furthermore, the test platform is fixedly provided with two symmetrically arranged mounting seats, each of which is slidably connected to the test platform in the horizontal direction, and the sliding directions of the two mounting seats are consistent. The test platform is fixedly provided with two linear drive mechanisms, each of which is connected to the corresponding mounting seat to drive it to translate. The two rotary cams are respectively rotatably connected to the two mounting seats.

[0012] Furthermore, each of the rotating cams has a raised layer arranged around its circumference on its outer peripheral surface. One end of the raised layer forms a sudden drop step between itself and the outer peripheral surface of the rotating cam, and the other end of the raised layer forms a gradual rise transition portion that smoothly transitions with the outer peripheral surface of the rotating cam.

[0013] Furthermore, the transmission mechanism includes a drive motor, a drive rod, and two bevel gear transmission components. The drive rod is horizontally positioned and rotatably connected to the test platform. The output end of the drive motor is connected to the drive rod. Splines are provided on the outer walls of both ends of the drive rod. Each bevel gear transmission component includes a first bevel tooth and a second bevel tooth that mesh with each other. The first bevel tooth is coaxially fixed to the corresponding rotary cam, and the axis of each rotary cam is perpendicular to the axis of the drive rod. A cantilever bracket is fixedly provided on each mounting base. The second bevel tooth is rotatably connected to the cantilever bracket and axially fixed. The center of the second bevel tooth is provided with a spline groove that fits onto the drive rod and engages with the spline tooth.

[0014] Furthermore, the front wheel is connected to the steering head tube via a front fork simulator. The front fork simulator includes a guide rod and a first extension frame. The guide rod is inserted and fixed to the steering head tube. A second sleeve for the guide rod to be inserted is fixed on the first extension frame. One end of the second sleeve has an elastic contraction opening and a second tube clamp is fitted on it. The front wheel is rotatably connected to the lower end of the first extension frame.

[0015] Furthermore, the rear wheel is connected to the rear swingarm mounting lug via a rear fork simulator. The rear fork simulator includes a T-shaped connecting arm and a second extension frame. The short shaft of the T-shaped connecting arm is fixedly connected to the rear swingarm mounting lug. A third sleeve is fixedly provided on the second extension frame. The long shaft of the T-shaped connecting arm is inserted into the third sleeve. One end of the third sleeve is provided with an elastic contraction opening, and a third tube clamp is fitted onto it. The rear wheel is rotatably connected to the lower end of the second extension frame.

[0016] The beneficial effects of this invention compared to the prior art are: This invention, on the one hand, directly connects the front and rear wheels mounted on the chassis body downwards onto two rotating cams synchronously driven by a transmission mechanism. This breaks away from the rigid tension and compression mode of traditional equipment that uses rigid anchoring of nodes, realistically replicating the process of dynamic alternating stress transmitted from road undulations to the chassis through the wheels. It establishes a highly realistic whole-vehicle bump stress model, significantly improving the accuracy of fatigue data. On the other hand, this invention connects a front counterweight simulating the fuel tank load to the chassis bearing plate and connects this front counterweight to a limiting slide that can only slide vertically along the test platform. This structure, without interfering with the chassis's free vertical movement under the excitation force, forcibly restricts the left and right lateral degrees of freedom of the chassis body. It completely solves the problem that a high center of gravity chassis with a central counterweight is prone to deflection and overturning during violent jumping, ensuring the safety and stability of high-intensity continuous testing. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the vehicle frame. Figure 2 This is a three-dimensional structural diagram of the vehicle frame body when it is mounted on this test device; Figure 3 This is a plan view of the vehicle frame mounted on this test apparatus; Figure 4 This is a three-dimensional structural diagram of the connection between the limiting slide and the water tank. Figure 5 This is a plan view of the limit slide when it is connected to the water tank; Figure 6 This is a 3D structural diagram of a front fork simulator; Figure 7 This is a three-dimensional structural diagram of the rear fork simulator; Figure 8 It is an exploded three-dimensional structure diagram of the columnar counterweight and the annular fastening band; Figure 9 This is a three-dimensional structural diagram of the transmission mechanism; Figure 10 This is a three-dimensional structural diagram of the first and second bevel serrations; Figure 11 This is a schematic diagram of the three-dimensional structure of a rotary cam. Figure 1 ; Figure 12 This is a schematic diagram of the three-dimensional structure of a rotary cam. Figure 2 .

[0018] The following components are labeled in the diagram: 1. Steering head tube; 2. Load-bearing base plate; 3. Rear swingarm mounting lug; 4. Seat mounting bracket; 5. Test platform; 6. Transmission mechanism; 7. Rotary cam; 8. Front wheel; 9. Rear wheel; 10. Limiting slide; 11. Flexible load-bearing pad; 12. Columnar counterweight; 13. Annular fastening band; 14. Water tank; 15. Water inlet; 16. Sealing cap; 17. First sleeve; 18. Insert column; 19. First pipe clamp; 20. Positioning seat; 21. Vertical guide rail; 22. Slider; 23. Support plate; 24. Hydraulic cylinder 25. Mounting base; 26. Linear drive mechanism; 27. Raised layer; 28. Sudden drop step; 29. ​​Gradual rise transition section; 30. Drive motor; 31. Drive rod; 32. Spline tooth; 33. First bevel tooth; 34. Second bevel tooth; 35. Overhang bracket; 36. Spline groove; 37. Front fork simulator; 38. Guide rod; 39. Second sleeve; 40. First extension frame; 41. Second tube clamp; 42. Rear fork simulator; 43. T-shaped connecting arm; 44. Second extension frame; 45. Third sleeve; 46. Third tube clamp. Detailed Implementation

[0019] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0020] refer to Figures 1 to 12 The diagram illustrates a motorcycle frame fatigue testing device, primarily used for fatigue testing of the frame body. The frame body includes a steering head tube 1, a load-bearing base plate 2, a rear swingarm mounting lug 3, and a seat mounting bracket 4. The device includes a fixed test platform 5, serving as a stable support foundation for the entire system. The test platform 5 is equipped with a vibration excitation mechanism, comprising a transmission mechanism 6 and two horizontally spaced rotating cams 7. The transmission mechanism 6 drives the two rotating cams 7 to rotate synchronously, providing a continuous alternating excitation force. To withstand this excitation force, the device also includes test wheels, comprising a front wheel 8 and a rear wheel 9. The front wheel 8 and rear wheel 9 are detachably connected to the steering head tube 1 and the rear swingarm mounting lug 3 on the frame body, respectively. In the test state, the front wheel 8 and rear wheel 9 rest downwards on the two rotating cams 7, causing the rotating cams 7 to drive the frame body to vibrate up and down, thus establishing a basic road bump model.

[0021] During actual testing, those skilled in the art discovered that if a real shock-absorbing fork were used to connect the front wheel 8, the shock absorber would absorb most of the excitation force, leading to distortion of the fatigue stress transmitted to the frame body. Therefore, the front wheel 8 is connected to the steering head tube 1 via a fork simulation component 37 to achieve rigid force transmission. Figure 6As shown, the front fork simulation component 37 includes a guide rod 38 and a first extension frame 40. The guide rod 38 is inserted and fixed to the steering head tube 1. A second sleeve 39 for the guide rod 38 to be inserted is fixed on the first extension frame 40. One end of the second sleeve 39 is provided with an elastic contraction opening, and a second tube clamp 41 is sleeved on it. The operator can lock the guide rod 38 securely in the second sleeve 39 by locking the second tube clamp 41. The front wheel 8 is rotatably connected to the lower end of the first extension frame 40, thereby achieving efficient assembly of the front end.

[0022] Similarly, for the rear structure of the frame, a suspension support without shock absorber interference is also required. The rear wheel 9 is connected to the rear swingarm mounting lug 3 via the rear fork simulator 42, as shown below. Figure 7 As shown, the rear fork simulation component 42 includes a T-shaped connecting arm 43 and a second extension frame 44. The short shaft of the T-shaped connecting arm 43 is fixedly connected to the rear swingarm mounting lug 3. A third sleeve 45 is fixedly provided on the second extension frame 44. The long shaft of the T-shaped connecting arm 43 is inserted into the third sleeve 45. One end of the third sleeve 45 is provided with an elastic contraction opening, and a third tube clamp 46 is sleeved on it. Quick release and fixation are completed by locking the third tube clamp 46. The rear wheel 9 is rotatably connected to the lower end of the second extension frame 44 to ensure the lossless transmission of the rear end excitation force.

[0023] In order to apply realistic road impacts to the chassis body, such as Figure 11 and Figure 12 As shown, each rotating cam 7 has a raised layer 27 arranged around its circumference on its outer peripheral surface. One end of the raised layer 27 forms a sudden drop step 28 between itself and the outer peripheral surface of the rotating cam 7, and the other end of the raised layer 27 forms a gradual rise transition 29 that smoothly transitions to the outer peripheral surface of the rotating cam 7. When the rotating cam 7 rotates at high speed, the gradual rise transition 29 can simulate a vehicle going uphill or on a gently undulating road surface. When it turns to the sudden drop step 28, it can instantly cause the front wheel 8 or the rear wheel 9 to fall and jump, thus perfectly replicating the strong alternating impact condition when the vehicle runs over a deep pit or step.

[0024] Considering the significant differences in wheelbase among motorcycles of different engine displacements and models on the market, this test setup needs to be highly compatible. Therefore, if... Figure 2 and Figure 9 As shown, two symmetrically arranged mounting seats 25 are fixedly provided on the test platform 5. Each mounting seat 25 is slidably connected to the test platform 5 in the horizontal direction, and the sliding directions of the two mounting seats 25 are the same. Two linear drive mechanisms 26 are fixedly provided on the test platform 5. It should be noted that the linear drive mechanism 26 can be a precision ball screw slide driven by a servo motor. Each linear drive mechanism 26 is connected to the corresponding mounting seat 25 to drive it to translate, thereby freely adjusting the front and rear wheelbase. Two rotating cams 7 are rotatably connected to the two mounting seats 25 respectively and translate into position accordingly.

[0025] Maintaining stable and synchronized power input between the two rotating cams 7 during the aforementioned spacing adjustment process is a major technical challenge. To address this issue, as follows... Figure 9 and Figure 10 As shown, the transmission mechanism 6 includes a drive motor 30, a drive rod 31, and two bevel gear transmission components. The drive rod 31 is horizontally positioned and rotatably connected to the test platform 5. The output end of the drive motor 30 is connected to the drive rod 31 to provide global active force. Spline teeth 32 are provided on the outer walls of both ends of the drive rod 31. Each bevel gear transmission component includes a first bevel tooth 33 and a second bevel tooth 34 that mesh with each other. The first bevel tooth 33 is coaxially fixed to the corresponding rotating cam 7, and the axis of each rotating cam 7 is perpendicular to the axis of the drive rod 31. At the same time, each mounting base 25 is fixedly provided with a cantilever bracket 35. The second bevel tooth 34 is rotatably connected to the cantilever bracket 35 and axially fixed. The center of the second bevel tooth 34 is provided with a spline groove 36 that is sleeved on the drive rod 31 and cooperates with the spline tooth 32. Through this mechanical cooperative design, when the mounting base 25 is translated, the cantilever bracket 35 can force the second bevel tooth 34 to slide axially along the spline tooth 32, and can still receive the rotational torque transmitted by the drive rod 31 during the entire sliding process, which completely solves the problem of power disconnection under variable wheelbase.

[0026] During actual testing, those skilled in the art also discovered that the chassis, due to its high center of gravity, is highly susceptible to lateral rollover under severe alternating vertical vibrations, potentially leading to serious safety accidents or interrupting the test. Therefore, such as... Figure 2 , Figure 4 and Figure 5 As shown, this device is equipped with a limiting slide 10, and a positioning seat 20 is fixedly installed on the test platform 5. Two symmetrically arranged vertical guide rails 21 are fixedly installed on the top of the positioning seat 20. A slider 22 is slidably installed in each vertical guide rail 21. Considering that the frame body will tilt and jump in a forward and backward tilting posture when the front and rear wheels 9 are subjected to asynchronous excitation, the limiting slide 10 is rotatably connected between the two sliders 22. This rotatable connection design allows the limiting slide 10 to maintain a vertical sliding connection with the test platform 5 while adapting to and following the forward and backward tilting angle of the frame body. The change effectively prevents the slider 22 from getting stuck or mechanically jammed in the guide rail. In addition, a support plate 23 is provided below the limiting slide 10, and a hydraulic cylinder 24 for driving the support plate 23 to rise and fall is fixed in the positioning seat 20. During initial assembly, the hydraulic cylinder 24 lifts the support plate 23 to support the limiting slide 10, making it convenient for workers to connect the frame. When the test begins, the hydraulic cylinder 24 descends and disengages from the support plate 23, so that the limiting slide 10 only has the freedom of vertical sliding and forward and backward deflection. Under the premise of not interfering with the actual jumping posture of the frame, the left and right offset of the frame body is forcibly restricted.

[0027] To further improve the accuracy of fatigue test data and ensure that the stress model of the equipment is completely equivalent to the actual state of the vehicle, this device is equipped with a front counterweight. The front counterweight is detachably connected to the load-bearing base plate 2 to simulate the load on the fuel tank. Simultaneously, the limiting slide 10 is connected to the front counterweight, utilizing this load-bearing center point as the anti-tipping pull base. Specifically, as follows... Figure 2 As shown, the front counterweight is a water tank 14. The top of the water tank 14 is provided with a water inlet 15, and a sealing cap 16 is screwed on the water inlet 15. The advantage of using the water tank 14 as the counterweight carrier is that the operator can control the amount of water injected inside and adjust the weight to accurately simulate the vibration response of the vehicle under different center of gravity states such as full oil, half oil or empty oil. In addition, a quick-release connector is provided between the water tank 14 and the limiting slide 10 to fix the two together.

[0028] When facing high-intensity continuous testing tasks, the ease of docking of test pieces is particularly important. Therefore, such as... Figure 4 and Figure 5 As shown, a number of first inserts 17 are fixedly provided on the limiting slide 10. Each first insert 17 is vertically arranged and has an elastic contraction opening at one end. A number of inserts 18 corresponding to the first inserts 17 are fixedly provided at the bottom of the water tank 14. Each insert 18 passes through the bearing base plate 2 and is inserted into the corresponding first insert 17, so that the frame body is tightly clamped. At the same time, the number of quick-release connectors is the same as the number of first inserts 17. Each quick-release connector is a first tube clamp 19 sleeved on the elastic contraction opening of the first insert 17. Simply tightening the first tube clamp 19 can deform the insert and thus securely clamp the insert 18.

[0029] During actual testing, those skilled in the art discovered that if a metal block is used directly as a rigid counterweight at the seat position, the inertial impact of the metal block during violent bouncing can easily cause non-rigid impact damage to the frame, leading to premature test failure. Therefore, a rear counterweight is installed on the seat mounting bracket 4, such as... Figure 2 and Figure 8 As shown, the rear counterweight includes a flexible bearing pad 11 and several columnar counterweight blocks 12. The flexible bearing pad 11 is fitted and tied to the seat mounting bracket 4 to act as a buffer medium. The upper surface of the flexible bearing pad 11 is provided with several spaced annular fastening straps 13, and each annular fastening strap 13 is closed by a Velcro fastener to form a receiving ring. Each columnar counterweight block 12 is horizontally inserted into the corresponding receiving ring. This Velcro-style binding design not only eliminates rigid impact, but also allows testers to simulate the alternating stress at the rear of the vehicle when riding by drivers of different weights by increasing or decreasing the number of columnar counterweight blocks 12 at any time.

[0030] Furthermore, the core objective of this device is to effectively record and display the fatigue of the frame body to output clear test results throughout the alternating vibration test. During the actual test preparation phase, operators pre-attach strain gauges or triaxial accelerometers to key stress concentration areas of the frame body (such as the welded joint of the steering head tube 1, the bend of the load-bearing base plate 2, or the root of the rear swingarm mounting lug 3), and connect their data cables to an external fatigue test control terminal. As the rotating cam 7 continuously applies alternating vibration force, the device's control system automatically accumulates and records the number of cycles the motor-driven cam rotates (i.e., the fatigue vibration frequency); simultaneously, the control terminal's display screen plots and displays the stress-strain curves of each monitoring point in real time. When the frame body develops microcracks or undergoes localized plastic deformation and yielding due to prolonged mechanical fatigue, the structural stiffness at that point undergoes a sudden change, causing significant jumps, divergence, or precipitous drops in the stress-strain curve waveform on the display screen. By visually observing the abrupt change points of the curve and combining this with the system's recorded limit number of cycles, testers can accurately determine the fatigue life limit of the frame. At the same time, by combining visual inspection or penetrant testing of weak points after shutdown, the physical fatigue fracture morphology or crack direction can be directly displayed, thus forming a complete fatigue display framework from data curves to physical appearance, providing detailed data support for the structural optimization of the frame.

[0031] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A motorcycle frame fatigue testing device for conducting fatigue tests on the frame body, wherein the frame body is provided with a steering head tube (1), a bearing base plate (2), a rear swingarm mounting lug (3), and a seat mounting bracket (4), characterized in that, include: Test platform (5), fixed settings; The excitation mechanism is located on the test platform (5). The excitation mechanism includes a transmission mechanism (6) and two rotating cams (7) spaced apart in the horizontal direction. The transmission mechanism (6) is used to drive the two rotating cams (7) to rotate synchronously. The test wheel includes a front wheel (8) and a rear wheel (9), the front wheel (8) and the rear wheel (9) being detachably connected to the steering head tube (1) and the rear swingarm mounting lug (3), respectively; A front counterweight is detachably connected to the bearing base plate (2) to simulate the load of the fuel tank; and Limiting slide (10), the limiting slide (10) is slidably connected to the test platform (5) in the vertical direction, and the limiting slide (10) is connected to the front counterweight to limit the left and right displacement of the frame body; In the test state, the front wheel (8) and the rear wheel (9) are respectively attached downwards to the two rotating cams (7), so that the rotating cams (7) drive the frame body to vibrate up and down.

2. The motorcycle frame fatigue testing device according to claim 1, characterized in that, The rear counterweight is installed on the seat mounting bracket (4). The rear counterweight includes a flexible bearing pad (11) and several columnar counterweights (12). The flexible bearing pad (11) is attached to and tied to the seat mounting bracket (4). The upper surface of the flexible bearing pad (11) is provided with several spaced annular fastening bands (13). Each annular fastening band (13) is closed by a nylon hook and loop fastener to form a receiving ring. Each columnar counterweight (12) is horizontally inserted into the corresponding receiving ring.

3. The motorcycle frame fatigue testing device according to claim 1, characterized in that, The front counterweight is a water tank (14), the top of the water tank (14) is provided with a water inlet (15), a sealing cap (16) is screwed on the water inlet (15), and a quick-release connector is provided between the water tank (14) and the limiting slide (10) to fix the two together.

4. The motorcycle frame fatigue testing device according to claim 3, characterized in that, The limiting slide (10) is fixedly provided with a number of first inserts (17), each of the first inserts (17) is vertically arranged and has an elastic contraction opening at one end. The bottom of the water tank (14) is fixedly provided with a number of inserts (18) that correspond one-to-one with the first inserts (17). Each insert (18) passes through the bearing base plate (2) and is inserted into the corresponding first insert (17). The number of quick-release connectors is the same as the number of first inserts (17). Each quick-release connector is a first pipe clamp (19) fitted on the elastic contraction opening of the first insert (17).

5. The motorcycle frame fatigue testing device according to claim 1, characterized in that, The test platform (5) is fixedly provided with a positioning seat (20). The top of the positioning seat (20) is fixedly provided with two vertical guide rails (21) arranged symmetrically. Each vertical guide rail (21) is provided with a slider (22) slidingly. The limiting slide (10) is rotatably connected between the two sliders (22). The limiting slide (10) is provided with a support plate (23) below it. The positioning seat (20) is fixedly provided with a hydraulic cylinder (24) for driving the support plate (23) to rise and fall.

6. The motorcycle frame fatigue testing device according to claim 1, characterized in that, The test platform (5) is fixedly provided with two symmetrically arranged mounting seats (25). Each mounting seat (25) is slidably connected to the test platform (5) in the horizontal direction, and the sliding directions of the two mounting seats (25) are consistent. The test platform (5) is fixedly provided with two linear drive mechanisms (26). Each linear drive mechanism (26) is connected to the corresponding mounting seat (25) to drive it to translate. The two rotary cams (7) are rotatably connected to the two mounting seats (25) respectively.

7. The motorcycle frame fatigue testing device according to claim 1, characterized in that, Each of the rotating cams (7) has a raised layer (27) arranged around its circumference on its outer peripheral surface. One end of the raised layer (27) forms a sudden drop step (28) between itself and the outer peripheral surface of the rotating cam (7), and the other end of the raised layer (27) forms a gently rising transition part (29) that smoothly transitions to the outer peripheral surface of the rotating cam (7).

8. The motorcycle frame fatigue testing device according to claim 6, characterized in that, The transmission mechanism (6) includes a drive motor (30), a drive rod (31), and two bevel gear transmission components. The drive rod (31) is horizontally arranged and rotatably connected to the test platform (5). The output end of the drive motor (30) is connected to the drive rod (31) in a transmission manner. Spline teeth (32) are provided on the outer walls of both ends of the drive rod (31). Each bevel gear transmission component includes a first bevel tooth (33) and a second bevel tooth (34) that mesh with each other. The first bevel tooth (33) is coaxially fixed to the corresponding rotary cam (7), and the axis of each rotary cam (7) is perpendicular to the axis of the drive rod (31). A cantilever bracket (35) is fixedly provided on each mounting base (25). The second bevel tooth (34) is rotatably connected to the cantilever bracket (35) and axially fixed. The center of the second bevel tooth (34) is provided with a spline groove (36) that is sleeved on the drive rod (31) and cooperates with the spline tooth (32).

9. The motorcycle frame fatigue testing device according to claim 1, characterized in that, The front wheel (8) is connected to the steering head tube (1) via a front fork simulator (37). The front fork simulator (37) includes a guide rod (38) and a first extension frame (40). The guide rod (38) is inserted and fixed to the steering head tube (1). A second sleeve (39) for the guide rod (38) to be inserted is fixed on the first extension frame (40). One end of the second sleeve (39) is provided with an elastic contraction opening, and a second tube clamp (41) is sleeved on it. The front wheel (8) is rotatably connected to the lower end of the first extension frame (40).

10. A motorcycle frame fatigue testing device according to claim 1, characterized in that, The rear wheel (9) is connected to the rear swingarm mounting lug (3) via a rear fork simulator (42). The rear fork simulator (42) includes a T-shaped connecting arm (43) and a second extension frame (44). The short shaft of the T-shaped connecting arm (43) is fixedly connected to the rear swingarm mounting lug (3). A third sleeve (45) is fixedly provided on the second extension frame (44). The long shaft of the T-shaped connecting arm (43) is inserted into the third sleeve (45). One end of the third sleeve (45) is provided with an elastic contraction opening, and a third tube clamp (46) is sleeved on it. The rear wheel (9) is rotatably connected to the lower end of the second extension frame (44).

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