A sliding bearing friction and wear testing machine simulating varying dynamic loads

Abstract

The utility model relates to sliding bearing detection technical field, concretely relates to a kind of simulation change dynamic load's sliding bearing friction and wear testing machine, including organism and loading mechanism and dynamic pressure driving mechanism installed on it, loading mechanism includes hydraulic loading cylinder, loading rod, loading head and elastic push rod, limit ring is equipped on the organism, dynamic pressure driving mechanism is by the rotation shaft and dynamic cam group vertically arranged, dynamic cam group includes single cam disc, uniform cam disc and variable cam disc, which are all installed on the rotation shaft, dynamic cam group is switched by switching device to realize the cam disc transmission of elastic push rod, the present equipment can simulate constant frequency intermittent load, high-frequency intermittent load and non-constant irregular load respectively, covers the load characteristics in multiple actual scenes, improves the reliability of test data, the present equipment can quickly complete the switching of different cam disc, without stopping machine dismounting a large number of components, significantly improve test efficiency.

Description

Technical Field

[0001] This utility model relates to the field of sliding bearing testing technology, specifically to a sliding bearing friction and wear testing machine that simulates changing dynamic loads. Background Technology

[0002] As a critical transmission component in mechanical equipment, the friction and wear performance of sliding bearings directly affects the operational accuracy, reliability, and service life of the equipment. In actual operating conditions, sliding bearings often bear complex and variable dynamic loads, such as the periodic impacts of rail vehicles passing over joints, the non-constant loads caused by wind speed variations in wind power equipment, and irregular vibration loads that occur after equipment aging. Therefore, conducting friction and wear tests on sliding bearings under simulated dynamic loads under actual operating conditions is an important means of evaluating their performance and lifespan.

[0003] Currently, existing sliding bearing friction and wear testing machines have many limitations in dynamic loading: First, most equipment can only provide constant loads or simple periodic loads, making it difficult to simulate complex and variable non-constant impact loads, resulting in significant deviations between test results and actual working conditions; Second, load adjustment methods are complex, requiring machine shutdown and disassembly of numerous components when switching between different load modes, making operation cumbersome and inefficient, and failing to meet diverse testing needs; Third, during dynamic loading, the stability and accuracy of force transmission are insufficient, and load fluctuations are easily caused by mechanical vibration, component wear, etc., affecting the reliability of test data. Utility Model Content

[0004] Therefore, it is necessary to provide a sliding bearing friction and wear testing machine that simulates changing dynamic loads to address the existing technical problems.

[0005] To solve the problems of the existing technology, the technical solution adopted by this utility model is as follows:

[0006] This utility model provides a sliding bearing friction and wear testing machine for simulating varying dynamic loads, including a body and a loading mechanism and a dynamic pressure drive mechanism mounted thereon. The loading mechanism includes a hydraulic loading cylinder, a loading rod, a loading head, and an elastic push rod. The loading rod is fixed to the output end of the hydraulic loading cylinder, and the loading head is fixedly mounted to the end of the loading rod. The elastic push rod is driven by the hydraulic loading cylinder. The machine body is provided with a limiting ring that limits the initial position of the hydraulic loading cylinder. The dynamic pressure drive mechanism consists of a vertically arranged rotating shaft and a dynamic variable cam group. The dynamic variable cam group includes a single cam disk, a uniform cam disk, and a variable cam disk, all mounted on the rotating shaft. The edge of one of the cam disks in the dynamic variable cam group is tightly fitted with the end of the elastic push rod. The dynamic variable cam group is switched with the cam disk driven by the elastic push rod by a switching device. The dynamic variable cam group is quickly connected to the rotating shaft.

[0007] Preferably, the loading mechanism further includes a first mounting bracket mounted on the machine body. The elastic push rod consists of a first telescopic section, a second telescopic section, a contact transmission steel ball, and a first spring. The first mounting bracket is provided with a first mounting seat, a second mounting seat, and a third mounting seat. The first telescopic section and the second telescopic section are slidably connected. The contact transmission steel ball is fixedly mounted on the side of the first telescopic section near the variable cam assembly. The second telescopic section is slidably mounted on the first mounting seat. The first spring is fixedly mounted between the first telescopic section and the second telescopic section. The second mounting seat is located at the connection between the elastic push rod and the hydraulic loading cylinder. A limit ring is fixedly mounted on the second mounting seat. The third mounting seat is mounted on the loading rod. The contact transmission steel ball can engage with the edge of one of the single cam disc, the uniform cam disc, and the variable cam disc.

[0008] Preferably, the rotating shaft consists of a detachable connecting rod, a top connecting rod, and a lifting rod. The top connecting rod and the lifting rod are located at the upper and lower ends of the dynamic cam assembly, respectively. Each pair of cam discs is connected by a detachable connecting rod. The top of the detachable connecting rod can be threaded to the top connecting rod, and the bottom of the detachable connecting rod can be threaded to the lifting rod.

[0009] Preferably, the detachable connecting rod is divided into a first connecting shaft and a second connecting shaft. The second connecting shaft is located below the first connecting shaft and is threadedly connected to the first connecting shaft. The second connecting shaft is provided with a slot. Each cam disk in the dynamic cam assembly is provided with a locking block that engages with the second connecting shaft. Both the first and second connecting shafts are provided with limiting disks for limiting the cam disks. The limiting disks are in contact with the upper and lower surfaces of the dynamic cam assembly.

[0010] Preferably, a second mounting bracket is also installed on the machine body. The rotating shaft and the dynamic cam assembly are both installed in the second mounting bracket. A quick-release mounting plate is provided on the top of the second mounting bracket. A rectangular limiting groove for connecting the quick-release mounting plate is provided on the top of the second mounting bracket. A lifting sleeve is connected to the quick-release mounting plate, and the top connecting rod is installed on the lifting sleeve.

[0011] Preferably, the lifting rod consists of a rotating shaft and a rotating sleeve that can be vertically slidably sleeved on the rotating shaft. A rotating driver is fixedly installed at the bottom of the machine body. The output end of the rotating driver is fixedly connected to the bottom of the rotating shaft. The top of the rotating sleeve is fixedly connected to the lowest detachable connecting rod. The switching device is connected to the rotating sleeve for transmission.

[0012] Preferably, the switching device includes a lifting transmission plate and a lifting hydraulic cylinder. The lifting hydraulic cylinder is fixedly installed below the machine body. The lifting transmission plate is fixedly connected to the rotating sleeve. The output end of the lifting hydraulic cylinder is fixedly connected to the lifting transmission plate.

[0013] Preferably, a guide ring is provided between each cam disk in the dynamic cam assembly, and the radius of the guide ring is the same as the base circle radius of each cam disk.

[0014] Preferably, a positioning disc is installed on the rotating shaft, and a positioning notch is provided on the outer edge of the positioning disc. A positioning block that elastically fits the outer edge of the positioning disc is installed on the machine body. Positioning holes are provided on the positioning disc, single cam disc, uniform cam disc and variable cam disc. A detection sensor for detecting the position of the positioning hole is provided vertically upward on the machine body.

[0015] The advantages of this utility model compared to the prior art are:

[0016] 1. This equipment, through the single cam disk, uniform cam disk and variable cam disk in the dynamic cam group, can simulate constant frequency intermittent load, high frequency intermittent load and non-constant irregular load respectively, covering the load characteristics in a variety of real-world scenarios and improving the reliability of test data.

[0017] 2. The rotating shaft adopts a combination structure of detachable connecting rod, top connecting rod and lifting rod, and with quick-release mounting plate and rectangular limit groove, it realizes quick disassembly and assembly and overall replacement of dynamic cam group; the switching device can quickly complete the switching of different cam disks through the coordinated action of lifting hydraulic cylinder, lifting transmission plate and rotating sleeve, without stopping the machine to disassemble a large number of parts, which significantly improves the test efficiency.

[0018] 3. The point contact design of the transmission steel ball in the elastic push rod reduces friction and wear. The first spring acts as a buffer compression to avoid damage to components such as the hydraulic loading cylinder from rigid impact. The slot and block of the detachable connecting rod, the axial clamping of the limit plate, and the overall support of the second mounting bracket ensure the structural stability of the dynamic cam group during high-speed rotation and dynamic loading, reduce the risk of component loosening or deformation, and improve the accuracy and stability of the equipment when radial loading is applied. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of a sliding bearing friction and wear testing machine that simulates varying dynamic loads.

[0020] Figure 2 This is a partial three-dimensional structural diagram of a sliding bearing friction and wear testing machine that simulates varying dynamic loads;

[0021] Figure 3 This is a three-dimensional structural diagram of the loading mechanism in a sliding bearing friction and wear testing machine that simulates changing dynamic loads;

[0022] Figure 4 This is an exploded three-dimensional view of the loading mechanism in a sliding bearing friction and wear testing machine that simulates varying dynamic loads.

[0023] Figure 5 This is a three-dimensional structural diagram of the hydrodynamic drive mechanism in a sliding bearing friction and wear testing machine that simulates varying dynamic loads.

[0024] Figure 6 This is a three-dimensional structural diagram of a dynamically changing cam assembly in a sliding bearing friction and wear testing machine that simulates varying dynamic loads.

[0025] Figure 7 This is a three-dimensional exploded view of the dynamically changing cam assembly in a sliding bearing friction and wear testing machine that simulates changing dynamic loads.

[0026] Figure 8 This is an exploded top view of the dynamically changing cam assembly in a sliding bearing friction and wear testing machine that simulates changing dynamic loads.

[0027] The numbers on the map are:

[0028] 1. Body; 2. Loading mechanism; 3. Dynamic pressure drive mechanism; 4. Hydraulic loading cylinder; 5. Loading rod; 6. Loading head; 7. Elastic push rod; 8. Limiting ring; 9. Rotating shaft; 10. Variable cam assembly; 11. Single cam disc; 12. Uniform cam disc; 13. Variable cam disc; 14. Switching device; 15. First mounting bracket; 16. First telescopic section; 17. Second telescopic section; 18. Abutment transmission steel ball; 19. First spring; 20. First mounting seat; 21. Second mounting seat; 22. Third mounting seat; 23. Detachable 24. Connecting rod; 25. Top connecting rod; 26. Lifting rod; 27. First connecting shaft; 28. Second connecting shaft; 29. ​​Slot; 30. Locking block; 31. Limiting plate; 32. Second mounting bracket; 33. Quick-release mounting plate; 34. Rectangular limiting groove; 35. Lifting sleeve; 36. Rotating shaft; 37. Rotating sleeve; 38. Rotating driver; 39. Lifting transmission plate; 40. Lifting hydraulic cylinder; 41. Guide ring; 42. Positioning plate; 43. Positioning notch; 44. Positioning block; 45. Positioning hole; 46. Detection sensor. Detailed Implementation

[0029] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0030] like Figures 1-8The sliding bearing friction and wear testing machine simulating varying dynamic loads includes a body 1 and a loading mechanism 2 and a dynamic pressure drive mechanism 3 mounted thereon. The loading mechanism 2 includes a hydraulic loading cylinder 4, a loading rod 5, a loading head 6, and an elastic push rod 7. The loading rod 5 is fixed to the output end of the hydraulic loading cylinder 4, the loading head 6 is fixedly mounted to the end of the loading rod 5, and the elastic push rod 7 is connected to the hydraulic loading cylinder 4 via transmission. The body 1 is provided with a limiting ring 8 that limits the initial position of the hydraulic loading cylinder 4. The dynamic pressure drive mechanism 3 consists of a vertically arranged rotating shaft 9 and a dynamic variable cam group 10. The dynamic variable cam group 10 includes a single cam disk 11, a uniform cam disk 12, and a variable cam disk 13, all mounted on the rotating shaft 9. The edge of one of the cam disks in the dynamic variable cam group 10 is tightly fitted with the end of the elastic push rod 7. The dynamic variable cam group 10 is switched with the cam disk that is driven by the elastic push rod 7 by a switching device 14. The dynamic variable cam group 10 is quickly detached from the rotating shaft 9.

[0031] This device first utilizes the loading mechanism 2, which drives the loading rod 5 via the hydraulic loading cylinder 4. This drives the loading head 6 at the top of the loading rod 5 to apply a constant radial pressure to the outer wall of the sliding bearing. Then, the pressure is output through the dynamic pressure drive mechanism 3. By rotating the dynamic variable cam group 10, the elastic push rod 7 is intermittently pressed against the cam. When the cam disc in the dynamic variable cam group 10 that is in contact with the elastic push rod 7 rotates to the protruding part, the elastic push rod 7 is compressed and applies a pushing force to the hydraulic loading cylinder 4 connected to it. The pushing force is then transmitted to the loading head 6, thereby enhancing the radial pressure on the outer wall of the sliding bearing. When the single cam disc 11 or the uniform cam disc 12 is operating, the cam disc stably and intermittently provides additional loading force during constant rotation, thereby simulating the situation of continuous and stable intermittent pressure. Examples include mechanical devices that operate intermittently at a constant frequency in equipment, and the situation of being impacted at a constant speed when passing through the track joint during track travel. Compared with the single cam disc 11, the uniform cam disc 12 can quickly obtain more impact frequencies at the same rotation speed. Different cam discs can be selected for operation according to the actual simulation situation. The variable cam disk 13 can simulate uncontrollable impact forces, i.e., the impact interval and number of impacts are unstable. At this time, the radial compressive capacity of the sliding bearing can be further tested, simulating the impact of sliding bearings on uncontrollable factors in more actual use scenarios, such as the constantly changing impact force during the use of wind power bearings, and the impact of other devices on the bearings caused by equipment aging or inadequate maintenance after a period of use. In this way, the load-bearing capacity of the bearing can be tested more comprehensively, improving the accuracy of the test and the reliability of the experiment.

[0032] The dynamic cam assembly 10 can be quickly disassembled and replaced, thereby changing the loading state of the constant frequency impact and dynamic impact required for the experiment according to the actual testing needs, and improving the applicability of the equipment.

[0033] The loading mechanism 2 also includes a first mounting bracket 15 mounted on the body 1. The elastic push rod 7 is composed of a first telescopic section 16, a second telescopic section 17, a contact transmission steel ball 18, and a first spring 19. The first mounting bracket 15 is provided with a first mounting seat 20, a second mounting seat 21, and a third mounting seat 22. The first telescopic section 16 and the second telescopic section 17 are slidably connected. The contact transmission steel ball 18 is fixedly mounted on the side of the first telescopic section 16 near the dynamic cam assembly 10. The second telescopic section 17 is slidably mounted on the first mounting seat 20. The first spring 19 is fixedly mounted between the first telescopic section 16 and the second telescopic section 17. The second mounting seat 21 is located at the connection between the elastic push rod 7 and the hydraulic loading cylinder 4. The limiting ring 8 is fixedly mounted on the second mounting seat 21. The third mounting seat 22 is mounted on the loading rod 5. The contact transmission steel ball 18 can abut against the edge of one of the single cam disk 11, the uniform cam disk 12, and the variable cam disk 13.

[0034] When the dynamic cam assembly 10 of the dynamic pressure drive mechanism 3 begins to rotate, the edge of the cam disk comes into contact with the contact transmission steel ball 18 of the elastic push rod 7. As the cam disk continues to rotate, the protruding part of its contour gradually approaches the contact transmission steel ball 18, generating a radial thrust on the contact transmission steel ball 18. At this time, the contact transmission steel ball 18 transmits this thrust to the first telescopic section 16 fixedly connected to it, causing the first telescopic section 16 to slide towards the second telescopic section 17. Since the first telescopic section 16 and the second telescopic section 17 are slidably connected, and a first spring 19 is provided between them, the sliding of the first telescopic section 16 will compress the first spring 19, and its elastic force will be transmitted to the hydraulic loading cylinder 4 connected to the second telescopic section 17 through the second telescopic section 17. This thrust is transmitted through the hydraulic loading cylinder 4 and the loading rod 5, and finally acts on the loading head 6, increasing the radial pressure of the loading head 6 on the outer wall of the sliding bearing. When the protrusion of the cam disc rotates past the abutting transmission steel ball 18, its thrust on the abutting transmission steel ball 18 gradually decreases. The first spring 19 extends under its own elastic restoring force, driving the first telescopic section 16 to reset. At this time, the additional thrust transmitted to the hydraulic loading cylinder 4 disappears, and the pressure of the loading head 6 returns to the initial constant radial pressure state.

[0035] The contact between the transmission steel ball 18 and the edge of the cam disk significantly reduces frictional resistance through point contact, minimizing wear after long-term operation and extending the service life of the components. It also ensures accurate force transmission, preventing force loss due to excessive friction from affecting experimental data. The sliding connection between the first telescopic section 16 and the second telescopic section 17 allows for the compression of the elastic push rod 7, preventing damage caused by forced displacement when the distance between the hydraulic loading cylinder 4 and the bearing cannot be changed. Combined with the guiding function of the first mounting base 20, this ensures the stability of the telescopic section's movement trajectory during force transmission, preventing deviation or jamming and ensuring the loading force is always radial, thus improving loading stability. The first spring 19 plays a crucial buffering role. When the cam disk's protrusion rapidly impacts the transmission steel ball 18, the first spring 19 absorbs the instantaneous impact force through elastic deformation, preventing rigid impact from damaging components such as the hydraulic loading cylinder 4 and the loading rod 5. It also makes the change in loading force smoother, reducing the interference of force fluctuations on experimental results.

[0036] The rotating shaft 9 consists of a detachable connecting rod 23, a top connecting rod 24, and a lifting rod 25. The top connecting rod 24 and the lifting rod 25 are located at the upper and lower ends of the dynamic cam assembly 10, respectively. Each pair of cam discs is connected by a detachable connecting rod 23. The top of the detachable connecting rod 23 can be threaded to the top connecting rod 24, and the bottom of the detachable connecting rod 23 can be threaded to the lifting rod 25.

[0037] When assembling the variable cam assembly 10, firstly, select a single cam disk 11, a uniform cam disk 12, or a variable cam disk 13 according to experimental requirements, and arrange the cam disks in a preset order. Adjacent cam disks are connected by a detachable connecting rod 23. Specifically, the top of the detachable connecting rod 23 is threaded to the top connecting rod 24 located at the upper end of the variable cam assembly 10, and the bottom is threaded to the lifting rod 25 located at the lower end of the variable cam assembly 10. Through the tightening effect of the threaded engagement, the top connecting rod 24, the detachable connecting rod 23, each cam disk, and the lifting rod 25 form an integral rotating shaft 9 assembly, ensuring that the variable cam assembly 10 does not undergo relative displacement during rotation.

[0038] When different types of cam discs need to be replaced to simulate different working conditions, the original variable cam assembly 10 can be removed individually or as a whole simply by loosening the threaded connection between the detachable connecting rod 23 and the top connecting rod 24 and the lifting rod 25. Afterwards, the cam discs are reassembled according to the new experimental requirements, and the detachable connecting rod 23 is used again to reconnect with the top connecting rod 24 and the lifting rod 25, completing the installation of the new variable cam assembly 10. The threaded connection between the detachable connecting rod 23 and the top connecting rod 24 and the lifting rod 25 not only enables quick assembly and disassembly of the variable cam assembly 10, significantly shortening the time for replacing the cam disc and improving the equipment's debugging efficiency, but the lifting rod 25 can also be used to adjust the height position of the variable cam assembly 10 in conjunction with the overall structure, enabling the switching of the transmission cam disc. This ensures that the cam disc and the contact transmission steel ball 18 of the elastic push rod 7 maintain precise contact, further improving the stability and accuracy of the experiment.

[0039] The detachable connecting rod 23 is divided into a first connecting shaft 26 and a second connecting shaft 27. The second connecting shaft 27 is located below the first connecting shaft 26 and is threadedly connected to the first connecting shaft 26. The second connecting shaft 27 is provided with a slot 28. Each cam disk in the variable cam assembly 10 is provided with a locking block 29 that engages with the second connecting shaft 27. The first connecting shaft 26 and the second connecting shaft 27 are both provided with a limiting disk 30 for limiting the cam disk. The limiting disk 30 is in contact with the upper and lower surfaces of the variable cam assembly 10.

[0040] The rigid engagement of the slot 28 and the block 29 achieves circumferential fixation between the cam disk and the second connecting shaft 27, ensuring no relative slippage during rotation. When adjacent cam disks are connected by the detachable connecting rod 23, the limiting disks 30 located on the first connecting shaft 26 and the second connecting shaft 27 will respectively fit tightly against the upper and lower surfaces of the corresponding cam disks in the variable cam assembly 10, forming axial limiting.

[0041] The body 1 is also equipped with a second mounting bracket 31. The rotating shaft 9 and the dynamic cam assembly 10 are both installed in the second mounting bracket 31. The top of the second mounting bracket 31 is provided with a quick-release mounting plate 32. The top of the second mounting bracket 31 is provided with a rectangular limiting groove 33 for connecting the quick-release mounting plate 32. The quick-release mounting plate 32 is shaft-connected with a lifting sleeve 34, and the top connecting rod 24 is installed on the lifting sleeve 34.

[0042] During equipment operation, the second mounting bracket 31 bears the radial force generated by the rotating shaft 9, the variable cam assembly 10, and the transmission process. The quick-release mounting plate 32 simplifies the disassembly and assembly process of the rotating shaft 9 and the variable cam assembly 10. When it is necessary to replace the variable cam assembly 10 as a whole or to maintain the rotating shaft 9, the rotating shaft 9 and the variable cam assembly 10 can be removed from the second mounting bracket 31 simply by removing the quick-release mounting plate 32, which greatly shortens the equipment maintenance time.

[0043] The lifting rod 25 consists of a rotating shaft 35 and a rotating sleeve 36 that can be vertically slidably sleeved on the rotating shaft 35. A rotating driver 37 is fixedly installed at the bottom of the machine body 1. The output end of the rotating driver 37 is fixedly connected to the bottom of the rotating shaft 35. The top end of the rotating sleeve 36 is fixedly connected to the lowest detachable connecting rod 23. The switching device 14 is connected to the rotating sleeve 36 in a transmission connection.

[0044] The switching device 14 includes a lifting transmission plate 38 and a lifting hydraulic cylinder 39. The lifting hydraulic cylinder 39 is fixedly installed below the machine body 1. The lifting transmission plate 38 is fixedly connected to the rotating sleeve 36. The output end of the lifting hydraulic cylinder 39 is fixedly connected to the lifting transmission plate 38.

[0045] When it is necessary to switch the cam disc driven by the elastic push rod 7, the switching device 14 starts to work. The lifting hydraulic cylinder 39 drives the lifting transmission plate 38 to move vertically. The lifting transmission plate 38 simultaneously drives the rotating sleeve 36 to move synchronously, thereby driving the entire upper part of the rotating sleeve 36 to rise and fall synchronously. This, in turn, drives the entire variable cam group 10 and the top connecting rod 24 to rise and fall together. Different cam discs in the variable cam group 10 will change height accordingly. The cam disc that was originally in close contact with the abutting transmission steel ball 18 of the elastic push rod 7 gradually disengages, while the target cam disc gradually moves to the position where it is in close contact with the abutting transmission steel ball 18, thus completing the cam disc switching. After the switching is completed, the output end of the lifting hydraulic cylinder 39 remains in the current state, keeping the lifting transmission plate 38, rotating sleeve 36 and variable cam group 10 in the current position to ensure stable cooperation between the cam disc and the elastic push rod 7 in subsequent operations.

[0046] A guide ring 40 is also provided between each cam disk in the dynamic cam assembly 10. The radius of the guide ring 40 is the same as the base circle radius of each cam disk.

[0047] The design of the guide ring 40 having the same radius as the base circle of the cam disc ensures the continuity of force on the contact transmission steel ball 18 during the transition between cam discs, avoids impact force fluctuations caused by surface discontinuities, reduces wear on the elastic push rod 7 and the dynamic cam assembly 10, extends the service life of the components, and the temporary support of the guide ring 40 during the cam disc switching process reduces vibration and impact at the moment of switching, making the switching action smoother and improving the safety of equipment operation.

[0048] A positioning disk 41 is installed on the rotating shaft 9. The outer edge of the positioning disk 41 is provided with a positioning notch 42. A positioning block 43 that elastically fits the outer edge of the positioning disk 41 is installed on the machine body 1. Positioning holes 44 are provided on the positioning disk 41, the single cam disk 11, the uniform cam disk 12 and the variable cam disk 13. A detection sensor 45 for detecting the position of the positioning hole 44 is provided vertically upward on the machine body 1.

[0049] The positioning disk 41 rotates together with the rotating shaft 9. The positioning block 43 elastically fits against the outer edge of the positioning disk 41. When the positioning disk 41 rotates to the position where the positioning notch 42 and the positioning block 43 are opposite each other, the positioning block 43 will be embedded in the positioning notch 42. At this time, the pressure detection of the positioning block 43 changes. The positioning block 43 can automatically pop out of the positioning notch 42 as the positioning disk 41 continues to rotate. When the switching device 14 needs to work, the end of the elastic push rod 7 needs to be fitted with the base circle edge of the cam disk to facilitate smooth switching operations. The positioning block 43 can lock the switching angle, which is convenient for subsequent cam disk switching operations. The design of the positioning hole 44 can detect the installation accuracy of the cam disk and improve the accuracy of subsequent switching operations.

[0050] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A sliding bearing friction and wear testing machine for simulating varying dynamic loads, characterized in that, The machine body (1) includes a loading mechanism (2) and a dynamic pressure drive mechanism (3) mounted on it. The loading mechanism (2) includes a hydraulic loading cylinder (4), a loading rod (5), a loading head (6), and an elastic push rod (7). The loading rod (5) is fixed at the output end of the hydraulic loading cylinder (4), the loading head (6) is fixedly mounted at the end of the loading rod (5), and the elastic push rod (7) is connected to the hydraulic loading cylinder (4) in a transmission manner. The machine body (1) is provided with a limiting ring (8) that limits the initial position of the hydraulic loading cylinder (4). The dynamic pressure drive mechanism... The structure (3) consists of a vertically arranged rotating shaft (9) and a dynamic cam assembly (10). The dynamic cam assembly (10) includes a single cam disk (11), a uniform cam disk (12), and a variable cam disk (13) all mounted on the rotating shaft (9). In the dynamic cam assembly (10), the edge of one of the cam disks is tightly fitted with the end of the elastic push rod (7). The dynamic cam assembly (10) is switched with the cam disk driven by the elastic push rod (7) by the switching device (14). The dynamic cam assembly (10) is quickly connected to the rotating shaft (9).

2. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 1, characterized in that, The loading mechanism (2) also includes a first mounting bracket (15) mounted on the body (1). The elastic push rod (7) is composed of a first telescopic section (16), a second telescopic section (17), a contact transmission steel ball (18), and a first spring (19). The first mounting bracket (15) is provided with a first mounting seat (20), a second mounting seat (21), and a third mounting seat (22). The first telescopic section (16) and the second telescopic section (17) are slidably connected. The contact transmission steel ball (18) is fixedly mounted on the side of the first telescopic section (16) near the dynamic cam assembly (10). The second telescopic section (17) is slidably mounted on the first mounting seat (20). The first spring (19) is fixedly mounted between the first telescopic section (16) and the second telescopic section (17). The second mounting seat (21) is located at the connection between the elastic push rod (7) and the hydraulic loading cylinder (4). The limiting ring (8) is fixedly mounted on the second mounting seat (21). The third mounting seat (22) is mounted on the loading rod (5). The abutting transmission steel ball (18) can abut against the edge of one of the single cam disc (11), the uniform cam disc (12), and the variable cam disc (13).

3. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 1, characterized in that, The rotating shaft (9) is composed of a detachable connecting rod (23), a top connecting rod (24) and a lifting rod (25). The top connecting rod (24) and the lifting rod (25) are located at the upper and lower ends of the dynamic cam group (10), respectively. Each pair of cam discs is connected by a detachable connecting rod (23). The top of the detachable connecting rod (23) can be threaded to the top connecting rod (24), and the bottom of the detachable connecting rod (23) can be threaded to the lifting rod (25).

4. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 3, characterized in that, The detachable connecting rod (23) is divided into a first connecting shaft (26) and a second connecting shaft (27). The second connecting shaft (27) is located below the first connecting shaft (26) and is threadedly connected to the first connecting shaft (26). The second connecting shaft (27) is provided with a slot (28). Each cam disk in the dynamic cam group (10) is provided with a locking block (29) that engages with the second connecting shaft (27). The first connecting shaft (26) and the second connecting shaft (27) are provided with a limiting disk (30) for limiting the cam disk. The limiting disk (30) is in contact with the upper and lower surfaces of the dynamic cam group (10).

5. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 3, characterized in that, The body (1) is also equipped with a second mounting bracket (31). The rotating shaft (9) and the dynamic cam assembly (10) are both installed in the second mounting bracket (31). The top of the second mounting bracket (31) is provided with a quick-release mounting plate (32). The top of the second mounting bracket (31) is provided with a rectangular limiting groove (33) for the quick-release mounting plate (32) to be connected. The quick-release mounting plate (32) is connected to a lifting sleeve (34). The top connecting rod (24) is installed on the lifting sleeve (34).

6. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 3, characterized in that, The lifting rod (25) consists of a rotating shaft (35) and a rotating sleeve (36) that can be vertically slidably mounted on the rotating shaft (35). A rotating driver (37) is fixedly installed at the bottom of the machine body (1). The output end of the rotating driver (37) is fixedly connected to the bottom of the rotating shaft (35). The top of the rotating sleeve (36) is fixedly connected to the detachable connecting rod (23) at the bottom. The switching device (14) is connected to the rotating sleeve (36) in a transmission.

7. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 6, characterized in that, The switching device (14) includes a lifting transmission plate (38) and a lifting hydraulic cylinder (39). The lifting hydraulic cylinder (39) is fixedly installed below the machine body (1). The lifting transmission plate (38) is fixedly connected to the rotating sleeve (36). The output end of the lifting hydraulic cylinder (39) is fixedly connected to the lifting transmission plate (38).

8. The sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 1, characterized in that, A guide ring (40) is also provided between each cam disk in the dynamic cam assembly (10), and the radius of the guide ring (40) is consistent with the base circle radius of each cam disk.

9. A sliding bearing friction and wear testing machine for simulating varying dynamic loads according to claim 8, characterized in that, A positioning plate (41) is installed on the rotating shaft (9). The outer edge of the positioning plate (41) is provided with a positioning notch (42). A positioning block (43) that elastically fits the outer edge of the positioning plate (41) is installed on the machine body (1). Positioning holes (44) are provided on the positioning plate (41), the single cam plate (11), the uniform cam plate (12) and the variable cam plate (13). A detection sensor (45) for detecting the position of the positioning hole (44) is provided vertically upward on the machine body (1).

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