A testing device and method for mechanical product fatigue testing

Abstract

The application belongs to the field of mechanical product fatigue test, and discloses a testing device and method for mechanical product fatigue test. The device is composed of four parts, i.e. a product fixing part, a loading part, a cam part and a rocker arm part. The product fixing part is used for clamping and positioning the testing mechanical product, and the left end of the testing mechanical product is connected with the rocker arm part. When the testing mechanical product makes linear reciprocating motion after being electrified, the rocker arm part converts the linear motion into circular motion. The loading part is used for preloading the required load value of the test through a rectangular cross-section compression spring. The cam part is subjected to the load of the loading part. The device simulates the real working conditions to study the failure mode and its causes of the material, product or structure under repeated load.

Description

Technical Field

[0001] This invention belongs to the field of fatigue testing of mechanical products, and particularly relates to a testing device and method for fatigue testing of mechanical products. Background Technology

[0002] Fatigue testing evaluates the performance and durability of materials, products, or structures under repeated loads to predict their lifespan and reliability in actual use. Fatigue testing can uncover potential defects in materials or structures, helping to improve product performance. Analyzing the results of fatigue tests ensures the safety and reliability of products under various operating conditions, preventing safety accidents caused by fatigue failure. Product fatigue testing requires specialized load testing equipment. When the load required for fatigue testing exceeds 5000N, this load testing equipment must be placed in a high and low temperature test chamber for high and low temperature testing. Traditional methods of hanging weights are not feasible, partly because the weight is too large to fit into the test chamber, and partly because the test chamber cannot withstand the weight of 500kg. Therefore, product fatigue testing urgently needs a small-sized testing device capable of handling large loads. Summary of the Invention

[0003] This invention provides a testing device and method for fatigue testing of mechanical products. It studies the potential failure modes and causes of materials, products, or structures under repeated loading by simulating real-world working conditions. This device can also be used for durability testing and high / low temperature testing of mechanical products. By simulating various working conditions and environmental conditions in actual use, it detects whether the product will experience performance degradation, malfunctions, or failures during long-term use. Furthermore, the device is small in size and can handle large loads.

[0004] The technical solution of this invention: In a first aspect, the present invention provides a testing device for fatigue testing of mechanical products, the device comprising four parts: a loading component, a cam component, a rocker arm component, and a product fixing component; Among them, the product fixing component is used to clamp and position the test mechanical product, and the left end of the test mechanical product is connected to the rocker arm component; When the test mechanical product is powered on and performs linear reciprocating motion, the rocker arm component will convert the linear motion into circular motion; The loading component is used to preload the load value required for the test using a rectangular cross-section compression spring. The cam component is subjected to the load of the loading component. During the movement, the rocker arm component is connected to the cam component and moves in sync. Therefore, the rocker arm component is also subjected to the load of the loading component. When the cam of the cam component moves from the nearest point to the farthest point, it will compress the rectangular cross-section spring of the loading component in the opposite direction to compensate for the lateral load on the product when the connecting rod in the rocker arm component moves to a position perpendicular to the product's movement direction, thereby maintaining a constant load.

[0005] Furthermore, the device includes: a base plate 1, a bracket 2, a cylindrical pin 3, a first rectangular cross-section compression spring 4, a guide post 5, a screw 6, a shaft elastic retaining ring 7, a bracket 8, a washer 9, a bracket 10, a second rectangular cross-section compression spring 11, a cam 12, a key 13, a deep groove ball bearing 14, a driven shaft 15, a connecting rod 16, a radial spherical bearing 17, a bushing 18, a drive shaft 19, a rolling shaft 20, a cylindrical head socket screw 21, a cylindrical pin 22, a rocker arm 23, a bolt 24, a washer 25, a nut 26, a pin 27, a cylindrical head socket screw 28, a pressure plate 29, a handwheel 30, a pressure plate 31, a pad 32, a baffle 33, a connecting rod 34, a guide plate 35, a cylindrical pin 36, and a washer 37; The loading component consists of a cylindrical pin 3, a first rectangular section compression spring 4, a guide post 5, a screw 6, a bracket 10, a second rectangular section compression spring 11, a handwheel 30, a pressure plate 31, a pad 32, a baffle 33, a cylindrical pin 36, and a washer 37. The cam assembly consists of a shaft elastic retaining ring 7, a washer 9, a cam 12, a key 13, a deep groove ball bearing 14, a driven shaft 15, and a guide plate 35. The rocker arm assembly consists of bracket 8, connecting rod 16, radial joint bearing 17, bushing 18, drive shaft 19, rolling shaft 20, rocker arm 23, bolt 24, washer 25, nut 26, and connecting rod 34. The product fixing components consist of base plate 1, bracket 2, cylindrical head hexagon screw 21, cylindrical pin 22, pin 27, cylindrical head hexagon screw 28, and pressure plate 29.

[0006] Furthermore, in the loading component: The pressure plate 31, the first rectangular section compression spring 4, and the second rectangular section compression spring 11 slide on three guide posts 5 evenly distributed around the circumference. The screw 6 passes through the middle of the pressure plate 31 and is threadedly connected to the pressure plate. The two ends of the three guide posts 5 evenly distributed around the circumference are respectively connected to the brackets 10 on the left and right sides. The guide post 5 is blocked on the outside of the bracket 10 by a cylindrical pin 36 and a washer 37. The screw 6 is at the center of the three guide posts 5 evenly distributed around the circumference, and the two ends of the screw 6 are respectively connected to the two ends of the bracket 10. The guide posts 5 are marked with scale lines, and the guide posts 5 and the screw 6 are evenly distributed on the pressure plate 31.

[0007] Furthermore, by continuously rotating the handwheel 30 to the left, the first rectangular section compression spring 4 is compressed to the required scale position of the guide post 5 through the pad 32. The first rectangular section compression spring 4 applies a certain load to the baffle 33, and the baffle 33 pushes the cam 12 to move within the guide plate 35.

[0008] Furthermore, in the cam component: Cam 12 is connected to the shaft end of driven shaft 15 via deep groove ball bearing 14, key 13, shaft elastic retaining ring 7 and washer 9, and cam 12 is fixed in guide plate 35. The other end of driven shaft 15 is connected to the lower end of connecting rod 16 via key 13. The elastic retaining ring 7 for the shaft is installed in the groove of the driven shaft 15. The flat key 13 is embedded in the keyway of the driven shaft 15 and the cam 12, so that its side is in close contact with the keyway of the driven shaft 15, so as to realize the fixation and transmission between the driven shaft 15 and the cam 12, and to transmit the torque on the driven shaft 15 to the cam 12.

[0009] Furthermore, in the rocker arm component: One end of the driven shaft 15 is connected to the lower end of the connecting rod 16 via a key 13. One end of the driving shaft 19 is connected to the upper end of the connecting rod 16 via a radial joint bearing 17 and a shaft elastic retaining ring 7. The other end of the driving shaft 19 is connected to the upper end of the connecting rod 34. The lower end of the connecting rod 34 is connected to one end of the rolling shaft 20 via a key 13. The other end of the rolling shaft 20 is connected to the deep groove ball bearing 14 inside the bracket 8. The bracket 8 is connected to the base plate 1 via two cylindrical head socket head cap screws 21 and cylindrical pins 22. A deep groove ball bearing 14 is installed on the left end of the rocker arm 23, which is connected to the drive shaft 19. Two bushings 18 are installed at the connection between the rocker arm 23 and the drive shaft 19, which respectively support the radial spherical bearing 17, the inner ring of the deep groove ball bearing 14 and the connecting rod 16. The other end of the rocker arm 23 is connected and fixed to the test mechanical product through bolts 24, washers 25 and nuts 26 to form the rocker arm component.

[0010] Furthermore, in the product fixing components: The bracket 2 is fixed to the base plate 1 by the cylindrical head hexagon screw 21 and the cylindrical pin 22. The right end of the test mechanical product is positioned on the bracket 2 by two pins 27. Then, the left end of the test mechanical product is positioned and clamped by the cylindrical head hexagon screw 28 and the pressure plate 29, which restricts the relative position between the test mechanical product and the bracket 2.

[0011] Secondly, the present invention also provides a test method for fatigue testing of mechanical products, the method being implemented using the aforementioned apparatus, the method comprising: First, the test mechanical product is connected and fixed to the bracket 2 by the pin 27. Then, the front end of the test mechanical product is positioned and fixed to the rocker arm 23 by the bolt 24, washer 25, and nut 26. At this time, the test mechanical product is connected and fixed to the test device. Then loading begins. Before loading, the left pressure plate 31 is placed at the left end of the screw 6. Then the handwheel 30 is turned. The handwheel 30 is connected to the screw 6 through the cylindrical pin 3 and rotates together. At this time, the right pressure plate 31 is pushed to the left and screwed to the right thread of the screw 6. By continuously turning the handwheel 30 to move to the left, the first rectangular section compression spring 4 is compressed to the required scale of the guide post 5 through the pad 32. The first rectangular section compression spring 4 presses the right side baffle 33, which in turn pushes the cam 12. The cam 12 slides to the left along the guide post 5, which drives the connecting rod 16 on one side. The connecting rod 16 drives the drive shaft 19, which drives the rocker arm 23 to move to the left, thereby pulling the test mechanical product to achieve tensile load and conduct tensile fatigue test on the product. After the test is completed, the handwheel 30 is turned to the initial position. The principle of pressure testing is the same as that of tensile testing, only the direction of loading is opposite.

[0012] This invention provides a testing apparatus and method for fatigue testing of mechanical products. The apparatus simulates the cyclic loads experienced by mechanical products during long-term use to evaluate their service life and durability. Fatigue testing allows for understanding the performance and reliability of products under prolonged operating conditions; it can also identify potential defects in materials or structures, helping designers optimize the materials and structures of mechanical products and select more suitable materials and design solutions. This fatigue testing apparatus can also be used for durability testing of mechanical products. By simulating various working conditions and environmental conditions in actual use, it detects whether the product will experience performance degradation, malfunctions, or failures during long-term use. This helps assess the reliability and stability of the product, ensuring safe and stable operation throughout its entire service life, thereby reducing after-sales maintenance costs. Attached Figure Description

[0013] Figure 1 This is a front view of a testing device for fatigue testing of mechanical products provided by the present invention; Figure 2 This is a top view of a testing device used for fatigue testing of mechanical products; Figure 3 This is a left view of a testing device used for fatigue testing of mechanical products; Figure 4 This is a schematic diagram of the loading component of a testing device used for fatigue testing of mechanical products; Explanation of icon numbers: 1. Base plate; 2. Bracket; 3. Cylindrical pin; 4. First rectangular section compression spring; 5. Guide post; 6. Screw; 7. Shaft retaining ring; 8. Bracket; 9. Washer; 10. Bracket; 11. Second rectangular section compression spring; 12. Cam; 13. Key; 14. Deep groove ball bearing; 15. Driven shaft; 16. Connecting rod; 17. Radial spherical bearing; 18. Bushing; 19. Drive shaft; 20. Rolling shaft; 21. Socket head screw; 22. Cylindrical pin; 23. Rocker arm; 24. Bolt; 25. Washer; 26. Nut; 27. Pin; 28. Socket head screw; 29. ​​Pressure plate; 30. Handwheel; 31. Pressure plate; 32. Pad; 33. Baffle; 34. Connecting rod; 35. Guide plate; 36. Cylindrical pin; 37. Washer. Detailed Implementation

[0014] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0015] This invention provides a testing device for fatigue testing of mechanical products, comprising four parts: a product fixing component, a loading component, a cam component, and a rocker arm component. The device includes: a base plate 1, a bracket 2, a cylindrical pin 3, a first rectangular cross-section compression spring 4, a guide post 5, a screw 6, a shaft elastic retaining ring 7, a bracket 8, a washer 9, a bracket 10, a second rectangular cross-section compression spring 11, a cam 12, a key 13, a deep groove ball bearing 14, a driven shaft 15, a connecting rod 16, a radial spherical bearing 17, a bushing 18, a drive shaft 19, a rolling shaft 20, a cylindrical head socket head cap screw 21, a cylindrical pin 22, a rocker arm 23, a bolt 24, a washer 25, a nut 26, a pin 27, a cylindrical head socket head cap screw 28, a pressure plate 29, a handwheel 30, a pressure plate 31, a pad 32, a baffle 33, a connecting rod 34, a guide plate 35, a cylindrical pin 36, and a washer 37.

[0016] The product fixing component mainly secures and positions the product stably and reliably, ensuring accurate positioning within the product space. Simultaneously, the left end of the product connects to the rocker arm component. When the product is powered on and performs linear reciprocating motion, the rocker arm component converts this linear motion into circular motion. The loading component primarily uses a rectangular cross-section compression spring to preload the required load value for the test. The cam component is subjected to the load from the loading component. During movement, the rocker arm component and the cam component are closely connected and move in sync. Therefore, the rocker arm component is also subjected to the load from the loading component. When the cam of the cam component moves from its closest point to its farthest point, it compresses the rectangular cross-section spring of the loading component in the opposite direction. This compensates for the lateral load on the product when the connecting rod moves perpendicular to the product's direction of movement, thus maintaining a constant load.

[0017] The product fixing components (such as) Figure 1 , 2(As shown) includes a base plate 1, a bracket 2, cylindrical head socket screws 21, cylindrical pins 22, pins 27, cylindrical head socket screws 28, and a pressure plate 29. The bracket 2 is fixed to the base plate 1 by the cylindrical head socket screws 21 and cylindrical pins 22. The right end of the product part is positioned on the bracket 2 by two pins 27. The left end of the product part is positioned and clamped by the cylindrical head socket screws 28 and the pressure plate 29, restricting the relative position between the product part and the bracket 2 and preventing the product part from moving.

[0018] The pin 27 is mainly used to determine the relative position between the product parts and the bracket 2, restrict the degree of freedom of the product parts in space, and ensure the assembly accuracy and stability between the product parts and the bracket 2.

[0019] The loading component (such as) Figure 4 (As shown) includes a cylindrical pin 3, a first rectangular cross-section compression spring 4, guide posts 5, a screw 6, a bracket 10, a second rectangular cross-section compression spring 11, a handwheel 30, a pressure plate 31, a pad 32, a baffle 33, a cylindrical pin 36, and a washer 37. The pressure plate 31, the first rectangular cross-section compression spring 4, and the second rectangular cross-section compression spring 11 slide on three evenly distributed guide posts 5. The screw 6 is threadedly connected to the middle of the pressure plate 31. The two ends of the three evenly distributed guide posts 5 are respectively connected to the left and right sides of the bracket 10. The guide post 5 is blocked outside the left bracket 10 by the cylindrical pin 36 and the washer 37. The screw 6 is located at the center of the three evenly distributed guide posts 5 and also at both ends of the bracket 10. By continuously rotating the handwheel 30 to the left, the first rectangular section compression spring 4 is compressed to the required scale position of the guide post 5 through the pad 32. The first rectangular section compression spring 4 applies a certain load to the baffle 33, and the baffle 33 pushes the cam 12 to move within the guide plate 35. The guide posts 5 and screws 6 are evenly distributed on the pressure plate 31 (e.g., ...). Figure 1 , 3 As shown in the diagram, this symmetry means that the distribution is balanced, with no obvious clusters or sparse areas, and no bias. This clamping structure is simple to operate, reduces the labor intensity of workers, improves work efficiency, and the central clamping force ensures high consistency and reliability.

[0020] The guide post 5 is marked with scale lines (such as...). Figure 2 (as shown in the figure) so that the required load can be adjusted to the scale during loading, making the component more intuitive and accurate during the loading process.

[0021] The first rectangular section compression spring 4 and the second rectangular section compression spring 11 (e.g.) Figure 1As shown, its cross-sectional shape is rectangular. This structure allows it to provide a larger contact area when under pressure, thereby dispersing stress and improving the spring's load-bearing capacity. Rectangular compression springs have high stiffness and stability, and are not easily bent or deformed under force, thus providing better support and stability. Furthermore, as the loading component of the device, this rectangular spring can provide a large elastic force to meet the test requirements.

[0022] The cam component (e.g.) Figure 2 (As shown) includes a shaft retaining ring 7, a washer 9, a cam 12, a key 13, a deep groove ball bearing 14, a driven shaft 15, and a guide plate 35. The cam 12 is connected to the shaft end of the driven shaft 15 via the deep groove ball bearing 14, the key 13, the shaft retaining ring 7, and the washer 9, and the cam 12 is fixed in the guide plate 35. The other end of the driven shaft 15 is connected to the lower end of the connecting rod 16 via the key 13. The cam mechanism described is simple in structure and easy to design. With a suitable cam profile, the driven rod can achieve any predetermined motion law. It has a wide range of applications and can perform various forms of motion, including linear motion, oscillation, and constant velocity motion. Compared to linkage mechanisms, the cam mechanism is simpler to design and can accomplish tasks that linkage mechanisms cannot. Furthermore, the cam mechanism is relatively easy to manufacture, making it widely used in the mechanical field. In this device, the cam mechanism can achieve force balance. Specifically, when the rocker arm 23 pushes the connecting rod 34 to its uppermost or lowermost position (perpendicular to the horizontal plane), the load is at its minimum due to the force it must overcome. The cam will also rotate to its furthest position, at which point it moves to the right against the baffle 33, further compressing the spring and amplifying its elastic force. This compensates for the force overcome by the load when the connecting rod 34 moves to its uppermost or lowermost position (perpendicular to the horizontal plane), thus maintaining load balance.

[0023] The shaft elastic retaining ring 7 is installed in the groove of the driven shaft 15. Its main purpose is to fix the axial movement of the driven shaft 15 and prevent unnecessary movement or axial displacement of the driven shaft 15 or related components in the axial direction. By limiting the position of the shaft, the shaft elastic retaining ring 7 ensures the stability and reliability of the transmission system and can also effectively protect the shaft and reduce the impact of external impact, vibration or wear on the shaft.

[0024] The flat key 13 is embedded in the keyway of the driven shaft 15 and the cam 12, so that its side is in close contact with the keyway of the driven shaft 15 to prevent relative rotation between the two, thereby achieving fixation and transmission between the driven shaft 15 and the cam 12, and transmitting the torque on the driven shaft 15 to the cam 12, ensuring the stability and efficiency of the mechanical transmission.

[0025] The deep groove ball bearing 14 is a key support element, characterized by low frictional resistance and high speed, which can significantly reduce mechanical motion resistance and improve speed and energy efficiency. It can also be used in machine parts that bear radial loads or combined radial and axial loads, as well as machine parts that bear axial loads.

[0026] The rocker arm component (such as) Figure 2 (As shown) includes a bracket 8, a connecting rod 16, a radial spherical bearing 17, a bushing 18, a drive shaft 19, a rolling shaft 20, a rocker arm 23, a bolt 24, a washer 25, a nut 26, and a connecting rod 34. One end of the driven shaft 15 is connected to the lower end of the connecting rod 16 via a key 13 (e.g., ...). Figure 3 As shown), one end of the drive shaft 19 is connected to the upper end of the connecting rod 16 via a radial spherical bearing 17 and an elastic retaining ring 7 to prevent the shaft from falling off. The other end of the drive shaft 19 is connected to the upper end of the connecting rod 34. The lower end of the connecting rod 34 is connected to one end of the rolling shaft 20 via a key 13. The other end of the rolling shaft 20 is connected to a deep groove ball bearing 14 inside the bracket 8. The bracket 8 is connected to the base plate 1 via two cylindrical head socket head cap screws 21 and cylindrical pins 22. A deep groove ball bearing 14 is installed on the left end of the rocker arm 23, which is connected to the drive shaft 19. Two bushings 18 are installed at the connection between the rocker arm 23 and the drive shaft 19, respectively pressing against the radial spherical bearing 17, the inner ring of the deep groove ball bearing 14, and the connecting rod 16. The other end of the rocker arm 23 is connected and fixed to the test machinery product via bolts 24, washers 25, and nuts 26, thus forming the rocker arm assembly.

[0027] The rocker arm 23 is a mechanical transmission component that transmits and converts the direction of motion, adjusts the stroke, and realizes the lever effect of force. By designing the fulcrum position, the displacement pushed by the cam can be amplified or reduced, and the torque can be changed using the lever principle.

[0028] The deep groove ball bearing 14 determines the relative position of the drive shaft 19 and the rocker arm 23 and ensures their free rotation, while transmitting the load between them and can withstand large loads. The ball bearing reduces energy loss through rolling friction, supports rotating components, and can withstand combined radial and axial loads, thereby improving the transmission efficiency and lifespan of the drive shaft 19 and the rocker arm 23.

[0029] The radial spherical plain bearing 17 is mainly used to bear radial loads, while allowing for oscillation, tilting, or rotational motion at a certain angle. While bearing radial loads, it achieves multi-directional motion compensation and load transfer through spherical sliding contact, and adapts to durability requirements under complex working conditions.

[0030] The drive shaft 19 is connected and clamped to the rocker arm 23, connecting rod 16, connecting rod 34, radial spherical bearing 17, and deep groove ball bearing 14 by bushings 18 (e.g., Figure 2(As shown). Bushing 18 abuts against the inner ring of the radial spherical plain bearing 17, the deep groove ball bearing 14, and the connecting rod 16, respectively, to prevent the bearings from falling off. Because bushing 18 is machined by grinding, the inner hole has high precision. This method allows the drive shaft 19 to slide smoothly with the rocker arm 23, connecting rod 16, and connecting rod 34 without jamming. If wear occurs during use and the precision requirements are not met, only bushing 18 can be replaced. This structural design is highly precise, flexible in use, and facilitates subsequent maintenance of the device.

[0031] This invention also provides a test method for fatigue testing of mechanical products, comprising: First, use pin 27 (e.g.) Figure 2 (As shown) Connect and fix the product part to the bracket 2, and then use bolts 24, washers 25 and nuts 26 to position and fix the front end of the product part to the rocker arm 23. At this time, the product part is connected and fixed to the test device.

[0032] Then loading begins. Before loading, the left pressure plate 31 is placed at the left end of the screw 6. The handwheel 30 is then rotated. The handwheel 30 is connected to the screw 6 via the cylindrical pin 3 and rotates together. At this time, the right pressure plate 31 is pushed to the left and screwed to the right thread of the screw 6. By continuously rotating the handwheel 30 to move it to the left, the rectangular compression spring 4 is compressed through the pad 32 to the required mark on the guide post 5. The rectangular compression spring 4 presses the right baffle 33, which in turn pushes the cam 12. The cam 12 slides to the left along the guide post 5, which in turn drives the connecting rod 16 on one side. The connecting rod 16 drives the drive shaft 19, which in turn drives the rocker arm 23 to move to the left, thereby pulling the product to achieve tensile load, that is, to achieve the tensile fatigue test of the product. After the test is completed, the handwheel 30 is screwed back to the initial position.

[0033] The principle of pressure testing is the same as that of tensile testing, only the direction of loading is opposite.

[0034] 1. For new product development, the required quantity of products is relatively small, and dedicated testing benches have low utilization rates, long manufacturing cycles, and high costs. Using this fatigue testing device saves manufacturing costs, shortens the manufacturing cycle, and improves production efficiency, making it suitable for new products, urgently needed products, and small-batch production.

[0035] 2. Compared with specialized test benches and advanced technologies in the industry, this testing device has a simple structure, small size, can achieve large loads, has low manufacturing costs, and is easy to operate and maintain.

[0036] 3. The fatigue testing device can be used for fatigue testing of mechanical products, as well as durability testing and high / low temperature testing. Using this testing device can reduce manufacturing costs and improve production efficiency.

[0037] This invention provides a testing device for fatigue testing of mechanical products. This device assesses the service life and durability of mechanical products by simulating cyclic loads experienced during long-term use. Fatigue testing allows for understanding the performance and reliability of products under prolonged operating conditions; it can also identify potential defects in materials or structures, helping designers optimize the materials and structures of mechanical products and select more suitable materials and design solutions.

[0038] This fatigue testing apparatus can also be used for durability testing of mechanical products. By simulating various operating conditions and environmental factors in actual use, it detects whether the product will experience performance degradation, malfunctions, or failures during long-term use. This helps assess the product's reliability and stability, ensuring safe and stable operation throughout its entire service life, thereby reducing after-sales maintenance costs.

Claims

1. A testing device for fatigue testing of mechanical products, characterized in that, The device consists of four parts: a product fixing component, a loading component, a cam component, and a rocker arm component. Among them, the product fixing component is used to clamp and position the test mechanical product, and the left end of the test mechanical product is connected to the rocker arm component; When the test mechanical product is powered on and performs linear reciprocating motion, the rocker arm component will convert the linear motion into circular motion; The loading component is used to preload the required load value for the test using a rectangular cross-section compression spring; After the loading component is preloaded, when the test mechanical product is powered on and performs linear reciprocating motion, the cam component will be subjected to the load of the loading component. During the motion, the rocker arm component is connected to the cam component and moves in sync. Therefore, the rocker arm component will also be subjected to the load of the loading component. When the cam of the cam component moves from the closest point of the cam to the rectangular section compression spring on one side of the loading component to the farthest point of the cam to the rectangular section compression spring on the other side of the loading component, it will compress the rectangular section compression spring on that side of the loading component in the opposite direction. This is used to compensate for the lateral load applied to the product when the connecting rod in the rocker arm component moves to a position perpendicular to the product's movement direction, thereby maintaining a constant load. The loading component includes: a first rectangular cross-section compression spring, a guide post, a screw, a bracket, a second rectangular cross-section compression spring, a handwheel, a left pressure plate, and a right pressure plate; The left pressure plate, the right pressure plate, the first rectangular section compression spring, and the second rectangular section compression spring can slide on the three guide posts that are evenly distributed along the circumference. The screw passes through the middle of the left pressure plate and the right pressure plate and is threadedly connected to the pressure plate. The two ends of the three guide posts that are evenly distributed along the circumference are respectively connected to the brackets on the left and right sides. The two ends of the screw are respectively connected to the two ends of the brackets. The guide posts and the screw are evenly distributed on the pressure plate. Three guide posts evenly distributed along the circumference are sequentially equipped with a left pressure plate, a second rectangular section compression spring, a cam assembly, a first rectangular section compression spring, and a right pressure plate; the cam can slide along the guide post, and the handwheel is connected to the screw; The cam assembly includes: cam, key, deep groove ball bearing, driven shaft, and guide plate; The cam is connected to the end of the driven shaft via a deep groove ball bearing and a key, and the cam is fixed in the guide plate. The other end of the driven shaft is connected to the lower end of the connecting rod via a key. The cam can move within the guide plate; The flat key is embedded in the keyway of the driven shaft and the cam, so that its side fits tightly with the keyway of the driven shaft, thereby achieving fixation and transmission between the driven shaft and the cam, and transmitting the torque on the driven shaft to the cam. The rocker arm components include: bracket, connecting rod, radial spherical bearing, bushing, drive shaft, rolling shaft, rocker arm, bolt, washer, nut, and connecting rod; One end of the drive shaft is connected to the upper end of the connecting rod via a radial spherical bearing and a flexible retaining ring. The other end of the drive shaft is connected to the upper end of the connecting rod. The lower end of the connecting rod is connected to one end of the rolling shaft via a key. The other end of the rolling shaft is connected to a deep groove ball bearing inside the bracket. The bracket is fixedly connected to the base plate. A deep groove ball bearing is installed on the left end of the rocker arm, which is connected to the drive shaft. The other end of the rocker arm is connected and fixed to the left end of the test machinery product.

2. The testing device for fatigue testing of mechanical products according to claim 1, characterized in that, The loading components also include: a pad, a baffle, a cylindrical pin, and a gasket; In the loading component: the guide post is blocked on the outside of the left bracket by a cylindrical pin and a washer, and the screw is at the center of the three guide posts evenly distributed along the circumference. The guide post is marked with scale lines.

3. The testing device for fatigue testing of mechanical products according to claim 2, characterized in that, The handwheel can be continuously rotated to move the right pressure plate to the left, thereby compressing the first rectangular section compression spring to the required scale position on the guide post through the pad. The first rectangular section compression spring squeezes the right baffle to apply a preload, and the right baffle pushes the cam to slide to the left along the guide post, finally pulling the test mechanical product to achieve the pre-application of the tensile load.

4. The testing device for fatigue testing of mechanical products according to claim 1, characterized in that, The cam component also includes: a shaft elastic retaining ring and a washer; The cam is connected to the end of the driven shaft via a deep groove ball bearing, a flat key, a shaft retaining ring, and a washer, and the cam is fixed in the guide plate. The shaft retaining ring is installed in the driven shaft groove.

5. The testing device for fatigue testing of mechanical products according to claim 1, characterized in that, In the rocker arm component: One end of the driven shaft is connected to the lower end of the connecting rod via a key, and the bracket is connected to the base plate via two cylindrical head socket head cap screws and cylindrical pins. Two bushings are installed at the connection between the rocker arm and the drive shaft. One bushing has its two ends abutting against one side of the radial spherical bearing and the deep groove ball bearing on the rocker arm, respectively. The other bushing has its two ends abutting against the other side of the deep groove ball bearing on the rocker arm and the connecting rod, respectively. The other end of the rocker arm is connected and fixed to the left end of the test mechanical product by bolts, washers and nuts to form the rocker arm component.

6. The testing device for fatigue testing of mechanical products according to claim 1, characterized in that, The product fixing components include: base plate, bracket, cylindrical head hexagonal screws, cylindrical pins, pins, and pressure plate; In the product fixing components: the bracket is fixed to the base plate by cylindrical head hexagonal screws and cylindrical pins, the right end of the test mechanical product is positioned on the bracket by two pins, and the left end of the test mechanical product is positioned and clamped by cylindrical head hexagonal screws and pressure plates to limit the relative position between the test mechanical product and the bracket.

7. A test method for fatigue testing of mechanical products, characterized in that, The method is implemented using the apparatus described in any one of claims 1-6, and the method includes: First, the test mechanical product is connected and fixed to the bracket using pins. Then, the left end of the test mechanical product is positioned and fixed to the rocker arm using bolts, washers, and nuts. At this point, the test mechanical product is connected and fixed to the test device. Then begin the preloading of the required load value. Before loading, place the left pressure plate at the left end of the screw rod, and then turn the handwheel. The handwheel is connected to the screw rod through the cylindrical pin, and the two rotate together. At this time, push the right pressure plate to the left and screw it to the right thread of the screw rod. By continuously turning the handwheel, the right pressure plate is moved to the left, and then the first rectangular section compression spring is compressed through the pad to the required scale of the guide post. The first rectangular section compression spring presses against the right side baffle, which in turn pushes the cam. The cam slides to the left along the guide post, driving a connecting rod on one side. The connecting rod drives the drive shaft, which in turn drives the rocker arm to move to the left, thereby pulling the test mechanical product to achieve the pre-load. After the loading component is pre-loaded, when the test mechanical product is powered on and makes linear reciprocating motion, the cam component will be subjected to the load of the loading component. During the movement, the rocker arm component is connected to the cam component and moves in sync. Therefore, the rocker arm component will also be subjected to the load of the loading component. When the cam of the cam component moves from the closest point of the cam to the rectangular section compression spring on one side of the loading component to the farthest point of the cam to the rectangular section compression spring on the other side of the loading component, it will compress the rectangular section compression spring on that side of the loading component in the opposite direction. This is used to compensate for the lateral load applied to the product when the connecting rod in the rocker arm component moves to a position perpendicular to the product's movement direction, thereby maintaining a constant load. After the test is completed, turn the handwheel back to the initial position. The principle of pressure testing is the same as that of tensile testing, only the direction of loading is opposite.

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