An automobile drive shaft fatigue test device

Abstract

The present invention relates to the technical field of drive shafts for new energy vehicles, and discloses a fatigue test device for an automotive drive shaft, which includes a frame, and also includes a transmission connected to the top of the frame, a driving rod connected to the transmission, a driven rod connected to the driving rod, an external connection frame slidably connected inside the frame, a straight rod and an arc plate for guiding and limiting the sleeve frame. The uneven vibration force generated by the concave-convex drive belt acts on the driven rod through the external connection frame. At the same time, the straight rod makes the driven rod rotate reciprocally through the sleeve frame. By generating an uneven vibration force through the concave-convex drive belt and acting on the driven rod through the external connection frame, it can highly simulate the vibration of the actual road conditions, and the generated vibration is irregular, providing strong support for evaluating its fatigue performance under real working conditions, improving the quality and reliability of the drive shaft, making the weak links that are difficult to find in the conventional simple vibration test exposed during the test of the drive shaft, and improving the effectiveness and generality of the test results.

Description

Technical Field

[0001] The present invention relates to the technical field of drive shafts for new energy vehicles, and particularly to a fatigue test device for an automotive drive shaft. Background Art

[0002] An automotive drive shaft is a component that connects the engine of a vehicle to the drive wheels and is used to transmit power. Generally, it consists of a driving shaft, a driven shaft, a telescopic sleeve, and a universal joint. It can transmit the power output from the engine through the transmission to the drive axle. The universal joint and the telescopic sleeve are responsible for adapting to angle changes and length expansion and contraction respectively to ensure stable power transmission. Therefore, the drive shaft needs to have sufficient strength and strong durability to ensure stable operation under complex working conditions. Conducting fatigue tests is essential for accurately evaluating the performance of the drive shaft in actual use.

[0003] Currently, there are mainly two methods for fatigue testing of drive shafts of new energy vehicles: road tests and bench tests. In road tests, the vehicle equipped with the drive shaft is put into actual road driving, different road conditions are planned, and the driver is required to adopt various driving methods to make the drive shaft bear loads in a real environment to obtain fatigue data. The test results are close to actual applications, but the test cycle is long and the cost is extremely high. At the same time, the complex and uncontrollable factors in the road environment result in large discreteness of the test results, and it is also difficult to ensure accuracy and repeatability. Therefore, currently, the mainstream method is still to use bench tests in the laboratory to simulate the working conditions of the drive shaft with professional equipment and test its fatigue performance by applying periodic torque, speed and other loads. During the test, parameters such as the magnitude, frequency, and waveform of the load can be accurately controlled, and data such as stress, strain, and temperature can be monitored in real time. However, the actual road conditions are extremely complex, and the vehicle will bear complex alternating loads during driving, such as continuous changes in torque and bending moment when accelerating, decelerating, turning, and passing over uneven roads. It is difficult to accurately simulate bench tests, resulting in deviations between the test results and the actual situation.

[0004] For example, for a fatigue test device for an automotive drive shaft with the application number CN202311474401.6, it can adjust the position of the adjusting rod through double rods, and can adjust the vibration amplitude of the shaft rod, so as to achieve the vibration of two different amplitudes simultaneously, and thus apply different vibration forces to the driving and driven shafts. However, during vehicle driving, it is the wheels that are lifted and then dropped under the influence of the road surface to generate vibration, and then this vibration force is transmitted to the driving shaft through the driven shaft, rather than the driving shaft vibrating by itself. At the same time, the driven shaft in this application is always fixed and cannot effectively simulate the influence generated when the vehicle turns. In addition, in this application, springs are also provided at the bottom of the motor to achieve different vibration forces. However, this will cause the motor to vibrate when the transmission rod vibrates. Although the engine will move when the vehicle is driving, at this time it is the vehicle that moves, and the overall frame of the vehicle is large enough to provide effective support and fixation for the generator. During testing, in order to ensure sufficient output force, the motor is usually fixed to ensure the output rotation speed. However, when the motor outputs a large rotation speed, the test frame is simply unable to effectively support the motor, and the vibration of the motor itself will affect the drive shaft, resulting in deviations in the test results and affecting the overall life of the equipment. Moreover, when the vehicle is driving, the vibration it receives is not a gradually changing force. Usually, it is subjected to a suddenly large force, and then the vibration force suddenly decreases. Therefore, there are deviations between the fatigue test data of the existing device and the actual application scenario.

[0005] Therefore, a fatigue test device for an automotive drive shaft is proposed, which can more accurately test the fatigue test data of the drive shaft. Summary of the Invention

[0006] The purpose of the present invention is to provide a fatigue test device for an automotive drive shaft, which solves the problem that the true fatigue condition of the drive shaft in the actual driving application scenario is difficult to fit and there are significant deviations.

[0007] The technical solution of the present invention is: a fatigue test device for an automotive drive shaft, including a frame, and further including a transmission connected to the top of the frame, a driving rod connected to the transmission, a driven rod connected to the driving rod, an external frame slidably connected inside the frame, a sleeve frame sleeved outside the external frame, an arc plate fixedly connected to the top end of the frame, an uneven driving belt arranged inside the frame, a straight rod sleeved inside the frame, and a spring connected between the external frame and the frame. The middle part of the driven rod is located inside the external frame. The uneven driving belt is located below the external frame. The straight rod and the arc plate are used to guide and limit the sleeve frame. The uneven driving belt generates uneven vibration force and acts on the driven rod through the external frame. At the same time, the straight rod makes the driven rod rotate reciprocally through the sleeve frame.

[0008] Further, the sleeve frame includes a square sleeve sleeved outside one end of the driven rod, and a linkage rod fixedly connected to the bottom of the square sleeve.

[0009] Further, an arc notch is formed in the arc plate, a straight notch is formed in the straight rod, and the linkage rod penetrates through the straight notch and the arc notch.

[0010] Further, the concave-convex drive belt is located below the external frame. A plurality of circular bumps of different sizes are arranged on the outer surface of the concave-convex drive belt. The outer surface of the concave-convex drive belt is divided into a high convex surface, a flat convex surface, a short convex surface, an inclined convex surface and a smooth surface. The positions of the concave-convex drive belt without circular bumps are all smooth surfaces. The length of the circular bumps on the high convex surface is greater than that of the rest of the outer surface. The density of the number of circular bumps on the short convex surface is greater than that of the rest of the outer surface.

[0011] Further, a limiting frame is arranged in the middle of the top end of the machine frame. A support frame is arranged at the bottom of the machine frame. A servo motor is arranged on one side of the support frame. A transmission belt is sleeved on the output end of the servo motor. A bidirectional lead screw is rotatably connected inside the machine frame. A limiting rod is fixedly connected inside the machine frame. A plurality of support frames are provided. The concave-convex drive belt is rotatably connected inside the plurality of support frames.

[0012] Further, both ends of the straight rod are sleeved outside the bidirectional lead screw and the limiting rod respectively. The transmission belt is sleeved between the servo motor and the bidirectional lead screw. The concave-convex drive belt is connected to the output end of the servo motor.

[0013] Further, the distance between the bottom end of the linkage rod and the straight rod is greater than the length of the high convex surface. The length of the circular bumps on the inclined convex surface gradually increases in the direction away from the high convex surface.

[0014] Further, the external frame includes a hollow plate arranged on the top of the machine frame, a connecting rod fixedly connected to the bottom of the hollow plate, and a rotating wheel rotatably connected to the bottom of the connecting rod. A limiting arc groove is formed in the hollow plate. The rotating wheel is attached to the surface of the concave-convex drive belt. The center of the arc notch is located at the connection between the driving rod and the driven rod. The arc notch and the limiting arc groove are concentric.

[0015] Further, two limiting notch openings are symmetrically formed inside the limiting frame. A first shaft sleeve is sleeved outside the driving rod. Both ends of the first shaft sleeve are located inside the limiting notch openings. A second shaft sleeve is sleeved outside the driven rod. The top and bottom of the second shaft sleeve are located inside the limiting arc groove. The second shaft sleeve is located between the driven rod and the hollow plate.

[0016] Further, the transmission includes a driving motor fixedly connected to the top of the machine frame, a connecting sleeve fixedly connected to the output end of the driving motor, and the connecting sleeve is connected to the driving rod.

[0017] Advantages of the present invention:

[0018] By generating uneven vibration force through the concave-convex drive belt and acting on the driven rod through the external frame, it can highly simulate the vibration of the actual road conditions, and the generated vibration is irregular. With its unique design of high convex surface, flat convex surface, short convex surface, inclined convex surface and smooth surface on the outer surface, and the distribution of circular convex blocks of different sizes, the concave-convex drive belt provides strong support for evaluating its fatigue performance under real working conditions, enabling targeted optimization of the design, improving the quality and reliability of the drive shaft, exposing weak links in the drive shaft during the test that are difficult to detect in conventional simple vibration tests, and improving the effectiveness and generality of the test results.

[0019] The straight rod enables the sleeve frame to translate, and at the same time, the arc plate is used to guide the sleeve frame, making one end of the driven rod rotate around the connection point with the driving rod, simulating the torsional force borne by the drive shaft under conditions such as vehicle turning. This ensures that the movement trajectory of the driven rod is accurate during the simulated turning, approaching the movement state of the drive shaft during actual vehicle driving. It can efficiently and low-costly repeat the test multiple times, quickly obtain data, greatly shorten the R & D cycle, discover potential safety hazards in advance, prompt vehicle manufacturers to improve the design and manufacturing process of the drive shaft, and ensure the safe and stable operation of the vehicle under various driving conditions.

[0020] Through the cooperation of the straight rod with the bidirectional lead screw and the limit rod, and the interaction between the linkage rod in the sleeve frame and the straight slot and the arc slot, the torsional movement of the driven rod can be accurately controlled, precisely simulating the vehicle turning condition. The mechanical contact mode between the concave-convex drive belt and the external frame can also accurately transmit the uneven vibration force to the driven rod, highly restoring the complex vibration during vehicle driving, being able to more directly and accurately simulate the actual working condition, improving the accuracy of the test results, relying entirely on the mechanical structure to be able to operate continuously and stably without being affected by the outside, and at the same time being able to be quickly combined with existing equipment, avoiding large-scale equipment replacement. Brief Description of the Drawings

[0021] Figure 1 It is a three-dimensional structural schematic diagram of the first perspective of the present invention;

[0022] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0023] Figure 3 For the present invention Figure 2 The sectional view taken along A-A in it;

[0024] Figure 4 For the present invention Figure 3 The enlarged schematic diagram at B in it;

[0025] Figure 5 It is a structural schematic diagram of the arc plate of the present invention;

[0026] Figure 6 Schematic structural diagram of the external frame of the present invention;

[0027] Figure 7 For the present invention Figure 3 Enlarged schematic diagram at position C in the present invention;

[0028] Figure 8 Schematic structural diagram of the frame of the present invention;

[0029] Figure 9 Top view of the present invention;

[0030] Figure 10 Front view of the present invention.

[0031] In the figure: 1. Frame; 101. Limiting frame; 1011. Limiting notch; 102. Support frame; 103. Servo motor; 104. Transmission belt; 105. Bi-directional lead screw; 106. Limiting rod; 2. Transmission; 21. Driving motor; 22. Connecting sleeve; 3. Active rod; 4. Driven rod; 5. External frame; 51. Hollowed-out plate; 511. Limiting arc groove; 52. Connecting rod; 53. Runner; 6. Sleeve frame; 61. Square sleeve; 62. Linking rod; 7. Arc plate; 71. Arc notch; 8. Concave-convex driving belt; 81. High convex surface; 82. Flat convex surface; 83. Short convex surface; 84. Oblique convex surface; 85. Smooth surface; 801. Round convex block; 9. Straight rod; 91. Straight notch; 10. Spring; 11. First shaft sleeve; 12. Second shaft sleeve. Detailed implementation manners

[0032] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given in conjunction with the accompanying drawings of the specification.

[0033] Referring to Figures 1-10 , which is an embodiment of the present invention, a fatigue test device for an automobile drive shaft is provided, including a frame 1, and further including a transmission 2 connected to the top of the frame 1, an active rod 3 connected to the transmission 2, a driven rod 4 connected to the active rod 3, an external frame 5 slidably connected inside the frame 1, a sleeve frame 6 sleeved outside the external frame 5, an arc plate 7 fixedly connected to the top end of the frame 1, a concave-convex driving belt 8 arranged inside the frame 1, a straight rod 9 sleeved inside the frame 1, and a spring 10 connected between the external frame 5 and the frame 1. The middle part of the driven rod 4 is located inside the external frame 5. The concave-convex driving belt 8 is located below the external frame 5. The straight rod 9 and the arc plate 7 are used to guide and limit the sleeve frame 6. The uneven vibration force generated by the concave-convex driving belt 8 acts on the driven rod 4 through the external frame 5. At the same time, the straight rod 9 makes the driven rod 4 rotate reciprocally through the sleeve frame 6.

[0034] Specifically, the concave-convex drive belt 8 can be made of elastic materials such as rubber or polyurethane, and has regular or irregular concave-convex structures on its surface. When the concave-convex drive belt 8 rotates, its outer surface continuously contacts the bottom of the external connection frame 5, thereby generating uneven vibration force. This vibration force is transmitted to the driven rod 4 through the external connection frame 5 to simulate the irregular vibration received during vehicle driving. The straight rod 9 and the arc plate 7 guide and limit the sleeve frame 6. When the straight rod 9 moves, the sleeve frame 6 moves along the path inside the arc plate 7, enabling the driven rod 4 to rotate reciprocally, effectively making up for the deficiency of the existing device in simulating the influence of vehicle turning, and making the test results closer to the actual situation.

[0035] Refer to Figures 1-6 , the sleeve frame 6 includes a square sleeve 61 sleeved outside one end of the driven rod 4, and a linkage rod 62 fixedly connected to the bottom of the square sleeve 61. An arc notch 71 is formed on the arc plate 7, and a straight notch 91 is formed on the straight rod 9. The linkage rod 62 penetrates through the straight notch 91 and the arc notch 71. When the straight rod 9 drives the linkage rod 62 to translate, and since the linkage rod 62 is located inside the arc notch 71, the linkage rod 62 is guided by the arc notch 71, and thus the linkage rod 62 is double-guided. When the linkage rod 62 moves along with the straight rod 9, the top of the linkage rod 62 will move along the path of the arc notch 71, and at the same time the bottom of the linkage rod 62 will slide inside the straight notch 91. When the linkage rod 62 moves, the square sleeve 61 also moves accordingly, and one end of the driven rod 4 is connected to the square sleeve 61, so the square sleeve 61 drives one end of the driven rod 4 to move, while the other end of the driven rod 4 is connected to the driving rod 3 and cannot move, thus causing one end of the driven rod 4 to rotate.

[0036] Specifically, by pushing the entire sleeve frame 6 with the straight rod 9, one end of the driven rod 4 can be rotated. During long-term test operation, it can effectively reduce the looseness and wear between components, reduce the probability of equipment failure, and extend the overall service life of the test equipment. Moreover, by changing the shapes, sizes, and positional relationships of the straight notch 91 and the arc notch 71, the stress conditions of the drive shaft under different turning radii and angles of different vehicle models can be simulated, meeting diverse test requirements and providing a more flexible solution for the research and development and testing of the drive shaft. For example, for the different turning characteristics of small cars and large trucks, corresponding adjustments can be made to achieve precise simulation.

[0037] Refer to Figures 1-7, the concave-convex drive belt 8 is located below the external frame 5. Multiple circular bumps 801 of different sizes are arranged on the outer surface of the concave-convex drive belt 8. The outer surface of the concave-convex drive belt 8 is divided into a high convex surface 81, a flat convex surface 82, a short convex surface 83, an inclined convex surface 84, and a smooth surface 85. The positions on the concave-convex drive belt 8 where no circular bumps 801 are provided are all smooth surfaces 85. The length of the circular bumps 801 on the high convex surface 81 is greater than that of the rest of the outer surface, which can instantaneously generate a large-amplitude impact vibration force on the external frame 5, simulating the strong jolts received when the vehicle passes through large potholes or speed bumps during driving. The density of the circular bumps 801 on the short convex surface 83 is greater than that of the rest of the outer surface, similar to the vibration situation when the vehicle is driving on a continuous pebble road surface or a rough road surface. The length of the circular bumps 801 on the inclined convex surface 84 gradually increases in the direction away from the high convex surface 81, which will make the vibration force received by the external frame 5 show a regular gradual change process, and can simulate the stress state when the vehicle is driving on a road surface with a certain slope change or uneven undulation.

[0038] Refer to Figures 2-6 , a limit frame 101 is provided in the middle of the top of the frame 1, a support frame 102 is provided at the bottom of the frame 1, a servo motor 103 is provided on one side of the support frame 102, a transmission belt 104 is sleeved on the output end of the servo motor 103, a bidirectional lead screw 105 is rotatably connected inside the frame 1, a limit rod 106 is fixedly connected inside the frame 1, and multiple support frames 102 are provided. The concave-convex drive belt 8 is rotatably connected inside the multiple support frames 102.

[0039] Both ends of the straight rod 9 are respectively sleeved on the outer parts of the bidirectional lead screw 105 and the limit rod 106. The transmission belt 104 is sleeved between the servo motor 103 and the bidirectional lead screw 105. The concave-convex drive belt 8 is connected to the output end of the servo motor 103.

[0040] Among them, the concave-convex drive belt 8 and the transmission belt 104 are driven by the servo motor 103. The bidirectional lead screw 105 is rotated by the transmission belt 104. The straight rod 9 reciprocally translates along the path of the limit rod 106 by the bidirectional lead screw 105, thereby driving the linkage rod 62 to move.

[0041] Specifically, the concave-convex drive belt 8 starts to operate under the drive of the servo motor 103. As the concave-convex drive belt 8 rotates, different regions of its outer surface come into contact with the external connection frame 5 in sequence. When the high convex surface 81 contacts the external connection frame 5, the long circular convex block 801 generates a strong impact vibration force. When the flat convex surface 82 contacts the external connection frame 5, a relatively stable and moderately amplitude vibration is generated. The high-frequency small vibration brought by the short convex surface 83 and the gradually changing vibration force generated by the inclined convex surface 84 are transmitted to the driven rod 4. When the sleeve frame 6 moves along the guiding trajectories of the straight rod 9 and the arc plate 7, it drives the driven rod 4 to rotate reciprocally, simulating the torsional force borne by the transmission shaft under conditions such as vehicle turning. The spring 10 is connected between the frame 1 and the external connection frame 5, buffering and regulating the vibration force throughout the process, enabling the load borne by the driven rod 4 to provide more realistic test results, reducing the waste of R & D costs caused by inaccurate testing, and accelerating the R & D process of the product.

[0042] Refer to Figures 2-6 , the distance between the bottom end of the linkage rod 62 and the straight rod 9 is greater than the length of the high convex surface 81, so as to ensure that when the driven rod 4 moves under the influence of the concave-convex drive belt 8, the linkage rod 62 will not break away from the restriction of the straight rod 9.

[0043] Refer to Figures 1-8 Specifically, the external connection frame 5 includes a hollow plate 51 arranged at the top of the frame 1, a connecting rod 52 fixedly connected to the bottom of the hollow plate 51, and a rotating wheel 53 rotatably connected to the bottom of the connecting rod 52. The hollow plate 51 is provided with a limiting arc groove 511. The rotating wheel 53 is attached to the surface of the concave-convex drive belt 8, enabling the vibration force generated by the concave-convex drive belt 8 to be transmitted to the rotating wheel 53 more efficiently and directly, and then transmitted to the driven rod 4, enhancing the authenticity and accuracy of the simulation of vehicle driving vibration. The center of the arc groove 71 is located at the connection of the driving rod 3 and the driven rod 4, so that when the driven rod 4 rotates, it rotates around the connection point of the driving rod 3 and the driven rod 4. The arc groove 71 and the limiting arc groove 511 are concentric.

[0044] Specifically, the design that the limiting arc groove 511 on the hollow plate 51 is concentric with the arc groove 71 on the arc plate 7 ensures that when simulating conditions such as vehicle turning, the movement trajectory of the driven rod 4 is more accurate and closer to the movement state of the transmission shaft during actual vehicle driving, and.

[0045] Refer to Figures 1-10, two limiting slots 1011 are symmetrically opened inside the limiting frame 101. A first shaft sleeve 11 is sleeved outside the driving rod 3. Both ends of the first shaft sleeve 11 are located inside the limiting slots 1011. The limiting slots 1011 limit the first shaft sleeve 11, enabling the driving rod 3 to only move up and down and preventing the driving rod 3 from being affected by friction with external components. A second shaft sleeve 12 is sleeved outside the driven rod 4. The top and bottom of the second shaft sleeve 12 are located inside the limiting arc slots 511. The second shaft sleeve 12 is located between the driven rod 4 and the hollow plate 51. When the hollow plate 51 moves up and down, it drives the second shaft sleeve 12 and the driven rod 4 to move synchronously. The second shaft sleeve 12 supports the driven rod 4, preventing the driven rod 4 from directly contacting the hollow plate 51 and causing frictional damage.

[0046] Refer to Figures 1-10 , the transmission 2 includes a driving motor 21 fixedly connected to the top of the frame 1, and a connecting sleeve 22 fixedly connected to the output end of the driving motor 21. The connecting sleeve 22 is connected to the driving rod 3.

[0047] Specifically, this test device can effectively isolate the motor vibration, ensuring that the entire transmission shaft is mainly affected by the simulated vehicle driving condition load during the test, ensuring that the external test conditions are controllable, thereby improving the accuracy of the test results.

[0048] The working principle of the present invention is as follows: After the test device is started, first, the driving motor 21 starts the power transmission process. The connecting sleeve 22 connected to its output end drives the driving rod 3 to rotate. The driving rod 3 rotates outside the first bushing 11, avoiding friction interference with external components and ensuring stable power transmission. At the same time, the output end of the servo motor 103 is sleeved with a transmission belt 104, and the transmission belt 104 is sleeved between the servo motor 103 and the bidirectional lead screw 105, driving the bidirectional lead screw 105 to rotate. When the bidirectional lead screw 105 rotates, the straight rod 9 reciprocates along the path of the limiting rod 106. When the straight rod 9 drives the linkage rod 62 to translate, the top of the linkage rod 62 moves along the path of the arc-shaped notch 71, and the bottom slides in the straight notch 91. This double guidance enables the linkage rod 62 to drive the square sleeve 61 to move, and further enables one end of the driven rod 4 to rotate around the connection point with the driving rod 3, simulating the torsional force borne by the transmission shaft under conditions such as vehicle turning. Since the center of the arc-shaped notch 71 is located at the connection between the driving rod 3 and the driven rod 4, and the arc-shaped notch 71 and the limiting arc groove 511 of the hollowed-out plate 51 on the external frame 5 are concentric, it ensures that the movement trajectory of the driven rod 4 is accurate during the simulated turning, approaching the movement state of the transmission shaft during actual vehicle driving. At the same time, the servo motor 103 also drives the concave-convex drive belt 8 to operate. The concave-convex drive belt 8 is rotatably connected inside a plurality of support frames 102, and these support frames 102 are arranged at the bottom of the frame 1, enhancing the overall stability. The high convex surface 81, flat convex surface 82, short convex surface 83, inclined convex surface 84, and smooth surface 85 on the outside of the concave-convex drive belt 8 are provided with a plurality of circular convex blocks 801 of different sizes. When the concave-convex drive belt 8 rotates, its outer surface contacts the runner 53, causing the hollowed-out plate 51 and the connecting rod 52 to move upward, and at the same time stretching the spring 10. The external frame 5 will transmit the uneven vibration force to the driven rod 4 through the external frame 5, simulating the irregular vibration received during vehicle driving.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An automobile drive shaft fatigue test device, comprising a frame (1), characterized in that: It further includes a driver (2) connected to the top of the frame (1), a driving rod (3) connected to the driver (2), a driven rod (4) connected to the driving rod (3), an external frame (5) slidably connected inside the frame (1), a sleeve frame (6) sleeved outside the external frame (5), an arc plate (7) fixedly connected to the top end of the frame (1), a concave-convex driving belt (8) arranged inside the frame (1), a straight rod (9) sleeved inside the frame (1), and a spring (10) connected between the external frame (5) and the frame (1). The middle part of the driven rod (4) is located inside the external frame (5). The concave-convex driving belt (8) is located below the external frame (5). The straight rod (9) and the arc plate (7) are used to guide and limit the sleeve frame (6). The uneven vibration force generated by the concave-convex driving belt (8) acts on the driven rod (4) through the external frame (5). At the same time, the straight rod (9) makes the driven rod (4) rotate reciprocally through the sleeve frame (6). The sleeve frame (6) includes a square sleeve (61) sleeved outside one end of the driven rod (4), and a linkage rod (62) fixedly connected to the bottom of the square sleeve (61). The concave-convex driving belt (8) is located below the external frame (5). A plurality of circular bumps (801) of different sizes are arranged on the outer surface of the concave-convex driving belt (8). The outer surface of the concave-convex driving belt (8) is divided into a high convex surface (81), a flat convex surface (82), a short convex surface (83), an inclined convex surface (84) and a smooth surface (85). The positions of the concave-convex driving belt (8) where no circular bumps (801) are provided are all smooth surfaces (85). The length of the circular bumps (801) on the high convex surface (81) is greater than that of the rest of the outer surface. The density of the circular bumps (801) on the short convex surface (83) is greater than that of the rest of the outer surface.

2. The fatigue test device for the automotive drive shaft according to claim 1, wherein: An arc notch (71) is formed on the arc plate (7), a straight notch (91) is formed on the straight rod (9), and the linkage rod (62) penetrates through the straight notch (91) and the arc notch (71).

3. The fatigue test device for an automotive drive shaft according to claim 2, characterized in that: A limiting frame (101) is arranged in the middle of the top end of the frame (1). A support frame (102) is arranged at the bottom of the frame (1). A servo motor (103) is arranged on one side of the support frame (102). A transmission belt (104) is sleeved on the output end of the servo motor (103). A bidirectional lead screw (105) is rotatably connected inside the frame (1). A limiting rod (106) is fixedly connected inside the frame (1). A plurality of support frames (102) are provided. The concave-convex driving belt (8) is rotatably connected inside the plurality of support frames (102).

4. The fatigue test device for an automotive drive shaft according to claim 3, wherein: Both ends of the straight rod (9) are respectively sleeved outside the bidirectional lead screw (105) and the limiting rod (106). The transmission belt (104) is sleeved between the servo motor (103) and the bidirectional lead screw (105). The concave-convex driving belt (8) is connected to the output end of the servo motor (103).

5. The fatigue test device for an automotive drive shaft according to claim 1, characterized in that: The distance between the bottom end of the linkage rod (62) and the straight rod (9) is greater than the length of the high convex surface (81), and the length of the circular convex block (801) of the inclined convex surface (84) gradually increases in the direction away from the high convex surface (81).

6. The fatigue test device for an automotive drive shaft according to claim 3, wherein: The external frame (5) includes a hollow plate (51) provided at the top of the frame (1), a connecting rod (52) fixedly connected to the bottom of the hollow plate (51), and a rotating wheel (53) rotatably connected to the bottom of the connecting rod (52). The hollow plate (51) is provided with a limiting arc groove (511). The rotating wheel (53) is in contact with the surface of the concave-convex drive belt (8). The center of the arc groove opening (71) is located at the connection of the driving rod (3) and the driven rod (4), and the arc groove opening (71) and the limiting arc groove (511) are concentric.

7. The fatigue test device for an automotive drive shaft according to claim 6, wherein: Two limiting groove openings (1011) are symmetrically formed inside the limiting frame (101). A first shaft sleeve (11) is sleeved outside the driving rod (3). Both ends of the first shaft sleeve (11) are located inside the limiting groove openings (1011). A second shaft sleeve (12) is sleeved outside the driven rod (4). The top and bottom of the second shaft sleeve (12) are located inside the limiting arc groove (511). The second shaft sleeve (12) is located between the driven rod (4) and the hollow plate (51).

8. The fatigue test device for the automotive drive shaft according to claim 1, wherein: The transmission (2) includes a driving motor (21) fixedly connected to the top of the frame (1), and a connecting sleeve (22) fixedly connected to the output end of the driving motor (21). The connecting sleeve (22) is connected to the driving rod (3).

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