A test device and test method for roller / cam rolling friction pairs

Abstract

This invention discloses a testing device and method for a roller / cam rolling friction pair. The testing system is used to test the mechanical loss of the roller / cam rolling friction pair under different loads and speeds. The testing system includes a roller testing module and an input shaft testing module. The roller testing module includes a roller bracket with two symmetrical through slots for mounting a first roller and a second roller, respectively. Bearings are installed inside both the first and second rollers. Mounting holes are formed on the upper and lower surfaces of the roller bracket, and the first and second roller supports pass through the mounting holes to fix the first and second rollers. The input shaft testing module includes a cylinder with a piston inside. One end of the piston is connected to a cam, and the other end is connected to the input shaft. The cam contacts the first and second rollers. A hydraulic power supply system provides pressurized oil to the testing system to simulate the load. A mechanical power supply system provides the torque required for the rotation of the testing device.

Description

Technical Field

[0001] This invention belongs to the field of rolling friction testing technology, and particularly relates to a rolling friction pair testing device and testing method for rollers / cams. Background Technology

[0002] Chinese patents CN106089621A, CN111396279A, and CN112901436A are all invention patents based on two-dimensional piston pumps. Their core components are rolling friction pairs composed of conical rollers and cam guides. The mechanical losses of rolling friction pairs under different speeds and loads are the focus and core of research on rolling friction pairs. However, current research on the mechanical losses of such rolling friction pairs under different speeds and loads is still lacking. The main reason for this is that the rollers and cam guides are installed inside the pump, and the limited space inside the pump makes it impossible to install sensors for measurement.

[0003] Therefore, there is an urgent need to develop a roller / cam rolling friction pair testing device to detect the mechanical loss of the rolling friction pair under different speeds and loads. This has an important impact on improving the mechanical efficiency of the pump and improving the pump's thermal balance. Summary of the Invention

[0004] To investigate the mechanical losses and slip rate of a roller relative to a cam caused by rolling on a cam under different speeds and loads, this invention provides a roller / cam rolling friction pair testing device and method. The roller / cam rolling friction pair testing device can measure the mechanical losses generated by the roller / cam rolling friction pair under different speeds and loads, and the slip rate of the roller relative to the cam during rotation.

[0005] The technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a roller / cam rolling friction pair testing device, comprising:

[0006] A testing system is used to test the mechanical loss of a roller / cam rolling friction pair under different loads and speeds. The testing system includes a roller testing module and an input shaft testing module. The roller testing module includes a roller support with two symmetrical through slots for mounting a first roller and a second roller, respectively. Bearings are installed inside both the first and second rollers. Mounting holes are formed on the upper and lower surfaces of the roller support, through which first and second roller supports pass to fix the first and second rollers. The input shaft testing module includes a cylinder body, one end of which is fixed to a front end cover. A wear-resistant sleeve is installed inside the cylinder body, and a piston is installed inside the wear-resistant sleeve. One end of the piston is connected to a cam, and the other end is connected to the input shaft. The wear-resistant sleeve, front end cover, input shaft, and piston form a hydraulic working chamber. The cam contacts the first and second rollers.

[0007] A hydraulic energy supply system for supplying pressurized oil to a test system to simulate a load;

[0008] A mechanical energy supply system, which is connected to an input shaft in the test system and is used to provide the torque required for the rotation of the test device.

[0009] Further, the hydraulic energy supply system includes a vane pump. The inlet of the vane pump is connected to an oil tank, and the outlet of the vane pump is respectively connected to an overflow valve and an accumulator; the overflow valve is used to adjust the pressure of the pressurized oil to provide different loads to the test system and serves as a safety valve.

[0010] Further, the upper surface of the roller support is fixedly connected to the top cover plate, and the lower surface of the roller support is fixedly connected to the lower support to prevent the first roller strut and the second roller strut from moving or falling out; the roller support is also provided with an arc-shaped groove on the side facing the cam to prevent interference with the movement of the cam.

[0011] Further, the lower support is in a "U" shape, and the bottom surface of the lower support is fixed to the working platform.

[0012] Further, the first roller and the second roller are tapered rollers, flat rollers or round rollers; the cam is a constant acceleration and deceleration cam, a sine-type cam or a cosine-type cam.

[0013] Further, through holes for passing hydraulic oil are opened on the end surface of the cylinder block; the cylinder block is fitted with a wear-resistant sleeve, and a U-shaped hole is opened on the end surface of the wear-resistant sleeve; the U-shaped hole is aligned with the through hole; the wear-resistant sleeve is made of a copper sleeve.

[0014] Further, a through hole for installing an input shaft is opened at the center of the front end cover. A rolling bearing is installed on the front end surface thereof, and an oil seal is installed on the rear end surface thereof; the front end cover is connected to an oil seal cover to fix the oil seal; the right end of the front end cover is fixed to the working platform through an L-shaped bracket.

[0015] Further, the other end of the piston is connected to the input shaft through a ball spline sleeve; the input shaft is designed as a stepped shaft, and symmetric upper and lower ball grooves are opened on the shaft head part of the input shaft, and the ball spline sleeve is fitted through the ball grooves; the shaft body part of the input shaft is used to limit the axial displacement of the rolling bearing installed on the front end cover; a key groove for installing a coupling is also opened on the shaft neck part of the input shaft.

[0016] The second aspect of the embodiments of the present invention provides a method for testing a roller / cam rolling friction pair, which is realized by the above-mentioned roller / cam rolling friction pair test device. The method includes:

[0017] S1, Test preparation stage: First, turn on the hydraulic power supply device, and the hydraulic oil flows into the hydraulic oil working chamber of the test system; under the action of hydraulic oil pressure, the cam runs to the left limit state, and the cam and the first roller and the second roller are in a tight state;

[0018] S2, activate the mechanical energy supply system to provide the required rotational speed and torque for the test device, and input shaft rotation;

[0019] S3 adjusts the pressure of the hydraulic oil supplied by the hydraulic energy supply system, thereby changing the force of the cam acting on the first and second rollers; by adjusting the speed supplied by the mechanical energy supply system, the speed of the input shaft and the cam is changed.

[0020] S4 measures the input torque of the motor in the system by using a torque / speed sensor, which is the resistance torque generated by the roller / cam friction pair, i.e., the mechanical loss generated by the roller / cam friction pair.

[0021] A third aspect of the present invention provides a method for measuring the relative slip rate between a roller and a cam, which is implemented by the roller / cam rolling friction pair testing device described above. The method specifically involves: a first roller and a second roller forming a roller; firstly, a non-reflective paint is applied to the surface of the roller; then, a reflective sheet is attached to the end of the roller; an infrared velocimeter is used to measure the actual rotation speed of the roller; the difference between the actual rotation speed and the theoretical rotation speed of the roller is calculated to obtain the relative slip rate between the roller and the cam.

[0022] The beneficial effects of this invention are mainly reflected in:

[0023] 1. The testing device of this invention separates the roller / cam rolling friction pair for individual testing. Different loads can be simulated by adjusting the pressure of the hydraulic oil through the relief valve, and the rotational speed of the cam can be controlled by adjusting the motor speed. The input torque of the motor in the mechanical energy supply system is measured using a torque / speed sensor. This input torque is the resistance torque generated by the cam / roller friction pair, i.e., the mechanical loss generated by the cam / roller friction pair. Through the above measurement method, the study of the mechanical losses generated by the roller / cam rolling friction pair under different loads and speeds can be successfully carried out.

[0024] 2. By measuring the roller speed using an infrared tachometer, the slip rate of the roller relative to the cam can be obtained under different loads and speeds. This is of great value in reducing the mechanical losses of the roller / cam rolling friction pair.

[0025] 3. The test objects of the test device of the present invention are universal. The form of rollers and cams is not limited to conical rollers and constant acceleration and deceleration cams. Rollers may also include flat rollers and round rollers; cams may also include sine type and cosine type. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 Schematic diagram of a test device for roller / cam rolling friction pairs;

[0028] Figure 2 A system for providing hydraulic energy;

[0029] Figure 3 This is a cross-sectional view of the test system;

[0030] Figure 4 A system that provides mechanical energy;

[0031] Figure 5 Exploded view of the roller test section of the test system;

[0032] Figure 6 For roller brackets;

[0033] Figure 7 A schematic diagram of roller support and roller installation;

[0034] Figure 8 An exploded view of the input axis test section of the test system;

[0035] Figure 9 This is a schematic diagram showing the installation of the cylinder block, copper bushing, and front end cap.

[0036] Figure 10 A schematic diagram showing the installation of the cam, piston, ball spline sleeve, and input shaft.

[0037] Figure 11 This is a cross-sectional view of the input shaft;

[0038] Figure 12 A cross-sectional view of the cam operating at its left limit;

[0039] Figure 13 A cross-sectional view of the cam operating at its right limit;

[0040] Figure 14 This diagram illustrates the use of an infrared velocimeter to collect the roller rotation speed. Detailed Implementation

[0041] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0042] The present invention will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0043] like Figure 1 As shown, an embodiment of the present invention provides a roller / cam rolling friction pair testing device, the device including a hydraulic energy supply system 1, a testing system 2 and a mechanical energy supply system 3.

[0044] like Figure 2 As shown, the hydraulic power supply system 1 supplies pressurized oil to the testing device 2 via hydraulic oil pipes. The hydraulic power supply system 1 consists of an accumulator 11, a vane pump 12, a relief valve 13, and an oil tank 14. The vane pump 12 supplies pressurized oil. The upstream end of the relief valve 13 is connected to the outlet of the vane pump 12, serving both to regulate system pressure and as a safety valve, while the downstream end is connected to the oil tank 14. The oil tank 14 is connected to the inlet of the vane pump 12 via hydraulic oil pipes, used to supply and store hydraulic oil. The accumulator 11 is installed at the outlet of the vane pump 12 to stabilize system pressure. The pressurized oil is supplied to the testing device 2 by the vane pump 12 via hydraulic oil pipes.

[0045] like Figure 4 As shown, the mechanical energy supply system 3 drives the motor 32 to output the torque required for the rotation of the testing device 2. The mechanical energy supply system 3 consists of a torque / speed sensor 31 and a motor 32. The motor 32 provides the torque required for the input shaft to rotate. The torque / speed sensor 31 is used to measure the motor speed and the provided torque. The output shaft of the motor 32, the torque / speed sensor 31, and the input shaft 210 of the testing system 2 are sequentially connected to each other via couplings.

[0046] like Figure 3 As shown, the test system 2 is divided into a roller test module and an input shaft test module.

[0047] The roller testing module includes a top cover plate 21, a roller bracket 217, a rolling bearing assembly 23 (composed of rolling bearings 231, 232, 233, and 234), rollers 24 (composed of a first roller 241 and a second roller 242), roller supports 221 and 222, and a lower support 216. Figure 5 and Figure 6As shown, the roller bracket 217 is a cuboid. Threaded holes 217a, 217b, 217c, and 217d are formed at the four corners of the top of the roller bracket 217, which are bolted to the top cover plate 21. Circular holes 217e and 217r are formed at the top and bottom of the roller bracket for mounting roller supports 221 and 222, respectively. Two symmetrical rectangular through slots 217f and 217k are formed on the front of the roller bracket 217 for mounting rollers 241 and 242. The roller bracket 217 also has arc-shaped grooves 217g and 217l on the side facing the cam to prevent interference with cam movement. Like the top, the bottom of the roller bracket has four threaded holes at the top corners for fixing the lower bracket 216.

[0048] The upper cover plate 21 is a rectangular cover plate with threaded holes at the four corners to fix it to the roller bracket 217, preventing the roller support 221 installed inside the roller bracket 217 from moving or falling out.

[0049] like Figure 7 As shown, both roller supports 221 and 222 are hollow stepped shafts. Taking roller support 221 as an example, the shoulder 221a provided on roller support 221 is used to hold the inner ring of bearing 231 installed in roller 241, so as to ensure that roller 241 can rotate freely inside roller bracket 217, but its displacement in the vertical direction of the support is restricted.

[0050] In this embodiment of the invention, rollers 241 and 242 are tapered rollers, each with two bearings installed inside. Taking roller 241 as an example, during installation, roller 241 is placed in the rectangular through groove 217f of roller bracket 217 and then fixed with roller support 221.

[0051] The lower support 216 is U-shaped, with four threaded holes on its upper end face for connecting the roller support 217 and preventing the roller support 222 from falling out. Two threaded holes are located on each side of its lower end face for connecting to the work platform. The lower support 216 also prevents the roller support installed below from shifting. The work platform is a cast iron plate used to fix the testing system.

[0052] like Figure 8 As shown, the input shaft test module includes a cylinder body 25, a copper sleeve 26, a piston 214, a cam 215, a rolling spline sleeve 213, an input shaft 210, a rolling bearing 29, an oil seal 211, an oil seal cover 28, a front end cover 27, and an L-shaped bracket 212. The piston 214, cam 215, rolling spline sleeve 213, and input shaft 210 are all moving parts.

[0053] The cylinder body 25 mates with the copper sleeve 26; one end of the cylinder body 25 is fixed to the front end cover 27; the cylinder body 25, the copper sleeve 26, and the front end cover 27 form a hydraulic working chamber; a piston 214 is provided inside the copper sleeve 26, one end of the piston 214 is connected to the cam 215, and the other end of the piston 214 is connected to the input shaft 210 through a rolling spline sleeve 213. In this embodiment of the invention, one end of the piston 214 is connected to the cam 215 through a rectangular key, and a groove for installing the rolling spline sleeve 213 is opened inside the piston 214. An oil seal 211 is also provided on the front end cover 27, and an oil seal cover 28 is fixed to the front end cover 27 by bolts. Several threaded holes are also opened along the circumferential direction on the outer edge of the front end cover 27, and it is fixed to one side of the L-shaped bracket 212 by bolts, and the other side of the L-shaped bracket 212 is fixed to the working platform.

[0054] Specifically, the cylinder body 25 is a hollow cuboid with a through hole on its upper end face for hydraulic oil to enter and exit. The upper end face of the cylinder body 25 also has four bolt holes for mounting hydraulic oil pipe flanges. The copper sleeve 26 is tightly fitted to the inner wall of the cylinder body 25 and serves as a wear-resistant sleeve for the piston 214. The copper sleeve is assembled to the cylinder body 25 using a heat-fitting process. During high-speed piston movement, it inevitably scrapes against the copper sleeve 26; therefore, the copper sleeve is used as a wear-resistant sleeve. In this embodiment, the copper sleeve is a thin-walled ring. The copper sleeve 26 also has a U-shaped hole for hydraulic oil to enter. After the copper sleeve 26 is installed and fitted with the cylinder body 25, the U-shaped groove aligns with the through hole on the cylinder body 25 for hydraulic oil to enter and exit. Threaded holes for mounting a front end cap 27 are provided at the four corners of the right side of the cylinder body 25. The front end cap 27 is fixed to the cylinder body 25 with bolts. The front cover 27 has a through hole at its center for mounting the input shaft 210, and steps at both the front and rear for mounting the rolling bearing 29 and oil seal 211. The copper sleeve 26, front cover 27, input shaft 210, and piston 214 form a cavity, which serves as a hydraulic working chamber. Hydraulic oil enters the cavity and acts on the piston 214. The side plates of the L-shaped bracket 212 are fixed to the front cover 27 and the working platform respectively by bolts.

[0055] The cam 215 is saddle-shaped on one side and has a circular hole for mounting the piston 214 on the other side. The cam 215 is then fixed to the piston 214 using a rectangular key. The piston 214 is a two-step cylindrical shape, with its largest outer circle fitting into the inner wall of the copper sleeve 26. A circular hole and bolt hole are located at its center for mounting the rolling spline sleeve 213. The rolling spline sleeve 213 is a standard part.

[0056] like Figure 11As shown, the input shaft 210 is designed as a stepped shaft; the head of the input shaft 210 has a row of symmetrical ball grooves 210a for engaging with the ball spline sleeve. The input shaft 210 has two symmetrical oil passages 210b on its left and right sides to prevent the left end face of the input shaft 210, the piston 214, and the ball spline sleeve 213 from forming a dead cavity. The right side of the shaft body of the input shaft 210 engages with the rolling bearing 29 installed in the front end cover 27 to limit the axial displacement of the rolling bearing 29 and prevent the pressure oil in the hydraulic working chamber from pushing the input shaft 210 to the right; the left side of the journal of the input shaft 210 engages with the inner ring of the rolling bearing 29 installed in the front end cover 27, and the right side of the journal of the input shaft 210 also has a keyway for installing a coupling.

[0057] The working principle of the roller / cam rolling friction pair testing device is as follows: First, the hydraulic power supply system is turned on, and pressurized oil flows through the cylinder and copper sleeve into the hydraulic working chamber. The pressurized oil pushes the piston. Because the piston and cam are fixedly connected, the cam will eventually move to its lowest point and contact the conical roller. At this time, both the cam and the piston have moved to the leftmost end of their stroke. Figure 12 Then the mechanical energy supply system is activated, and the motor starts rotating, driving the input shaft to rotate. The input shaft transmits the rotational motion to the piston via ball splines. Under the action of the pressurized oil and the input shaft, the piston can both rotate and reciprocate linearly; driven by the pressurized oil and the input shaft, both the cam and the piston move to the rightmost end of their stroke. Figure 13 At this point, the highest point of the cam contacts the conical roller, thus completing the function of simulating the two-dimensional piston movement inside a two-dimensional piston pump.

[0058] Based on the aforementioned roller / cam rolling friction pair testing device, this invention provides a method for testing roller / cam rolling friction pairs, specifically including the following steps:

[0059] S1, Test Preparation Phase: First, turn on the hydraulic power supply device 1. Hydraulic oil flows from the hydraulic pump 12 into the cavity formed by the copper sleeve 26, front end cover 27, input shaft 210, and piston 214 in the test system 2. Because the piston 214 can move freely at this time, under the action of high-pressure oil, the entire test system 2 will be in a state of high pressure. Figure 11 In this state, cam 215 and the two rollers 241 and 242 are in a close contact state.

[0060] S2, at the start of the test, the mechanical energy supply system 3 is turned on, and the motor 32 begins to rotate. The rotational mechanical energy is transmitted from the motor 32 to the test system 2 via the torque / speed sensor 31, and the input shaft 210 begins to rotate. Because the cam 215 is in close contact with the rollers 241 and 242, there must be a resistance torque generated by the cam / roller friction pair when the input shaft rotates.

[0061] S3, by adjusting the relief valve 13 in the hydraulic power supply system 1, the pressure of the high-pressure oil can be changed, thereby changing the force exerted by the cam 215 on the roller 24. By adjusting the motor speed, the rotational speed of the cam 215 can be changed.

[0062] S4, the input torque of the motor 32 in the mechanical energy supply system 3 is measured by the torque / speed sensor 31, which is the resistance torque generated by the roller / cam friction pair, i.e., the mechanical loss generated by the roller / cam friction pair. This completes the test of the mechanical loss generated by the roller / cam friction pair under different loads and speeds.

[0063] The embodiments of the present invention are based on the above-described roller / cam rolling friction pair testing device, such as... Figure 14 As shown, a method for measuring the relative slip rate between the roller and the cam is also provided, the method specifically being:

[0064] First, the surface of roller 24 is coated with non-reflective paint. A reflective sheet 219 is attached to the end of roller 24. Then, an infrared speed sensor 218 is used to measure the actual rotation speed of roller 24. The infrared speed sensor 218 and the end of roller 24 are on the same horizontal plane. The measured actual rotation speed of roller 24 can be compared with its theoretical rotation speed. The difference between the actual rotation speed and the theoretical rotation speed of roller 24 is calculated to obtain the relative slip rate between roller 24 and cam 215. This is very important for studying roller / cam friction pairs.

[0065] In this embodiment of the invention, the roller is designed as two parts (first roller 241 and second roller 242). The second roller 242 (i.e., the lower roller) is used to contact the cam guide rail and can be designed as a tapered roller, flat roller, or cylindrical roller. The first roller 241 (i.e., the upper roller) is coated with a non-reflective coating and has reflective sheets attached. The roller rotation speed is measured by an infrared tachometer, which can simultaneously measure the mechanical loss generated by the cam / roller friction pair and the relative slip rate between the roller and the cam.

[0066] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0067] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A testing device for roller / cam rolling friction pairs, characterized in that, include: The test system (2) is used to test the mechanical loss of the roller / cam rolling friction pair under different loads and speeds. The test system (2) includes a roller test module and an input shaft test module. The roller test module includes a roller bracket (217), which has two symmetrical through slots for mounting a first roller (241) and a second roller (242) respectively. Bearings are installed in both the first roller (241) and the second roller (242). Mounting holes are opened on the upper and lower surfaces of the roller bracket (217). The first roller support (221) and the second roller support (222) are also included. The first roller (241) and the second roller (242) are fixed by passing through the mounting holes respectively; the input shaft test module includes a cylinder (25), one end of which is fixed to the front end cover (27); a wear-resistant sleeve is provided inside the cylinder (25), and a piston (214) is provided inside the wear-resistant sleeve; one end of the piston (214) is connected to the cam (215), and the other end is connected to the input shaft (210); the wear-resistant sleeve, the front end cover (27), the input shaft (210), and the piston (214) form a hydraulic working chamber; the cam (215) contacts the first roller (241) and the second roller (242); A hydraulic energy supply system (1) is used to supply pressurized oil to the test system (2) to simulate a load; A mechanical energy supply system (3) is connected to the input shaft (210) in the test system (2) and is used to provide the torque required for the rotation of the test system (2); the mechanical energy supply system (3) consists of a torque / speed sensor (31) and a motor (32); The working principle of the roller / cam rolling friction pair testing device is as follows: First, the hydraulic energy supply system (1) is turned on, and the pressure oil flows through the cylinder (25) into the hydraulic working chamber. The pressure oil pushes the piston (214), and the cam (215) moves to its lowest point and contacts the first roller (241) and the second roller (242). At this time, both the cam (215) and the piston (214) move to the leftmost end of the stroke. Then, the mechanical energy supply system (3) is turned on, and the motor (32) starts to rotate, driving the input shaft (210) to rotate. When the input shaft (210) rotates, it transmits the rotational motion to the piston (214). Under the action of the pressure oil and the input shaft (210), the piston (214) can both rotate and reciprocate linearly. Driven by the pressure oil and the input shaft (210), both the cam (215) and the piston (214) move to the rightmost end of the stroke. At this time, the highest point of the cam (215) contacts the first roller (241) and the second roller (242), thus completing the function of simulating the two-dimensional piston motion inside the two-dimensional piston pump.

2. The roller / cam rolling friction pair testing device according to claim 1, characterized in that, The hydraulic energy supply system (1) includes a vane pump (12). The inlet of the vane pump (12) is connected to an oil tank (14), and the outlet of the vane pump (12) is respectively connected to a relief valve (13) and an accumulator (11). The relief valve (13) is used to adjust the pressure of the pressurized oil to provide different loads to the test system (2) and serves as a safety valve.

3. The roller / cam rolling friction pair testing device according to claim 1, characterized in that, The upper surface of the roller support (217) is fixedly connected to the top cover plate (21), and the lower surface of the roller support (217) is fixedly connected to the lower support (216) to prevent the first roller strut (221) and the second roller strut (222) from moving or falling out. The roller support (217) is also provided with an arc-shaped groove on the side facing the cam to prevent interference with the movement of the cam.

4. The roller / cam rolling friction pair testing device according to claim 3, characterized in that, The lower support (216) is in a "C" shape, and the bottom surface of the lower support (216) is fixed to the working platform.

5. The roller / cam rolling friction pair testing device according to claim 1, characterized in that, The first roller (241) and the second roller (242) are tapered rollers, flat rollers or round rollers; the cam (215) is a constant acceleration and deceleration cam, a sine-shaped cam or a cosine-shaped cam.

6. The roller / cam rolling friction pair testing device according to claim 1, characterized in that, Through holes for passing hydraulic oil are opened on the end surface of the cylinder block (25). The cylinder block (25) is fitted with a wear-resistant sleeve, and a U-shaped hole is opened on the end surface of the wear-resistant sleeve. The U-shaped hole is aligned with the through hole. The wear-resistant sleeve is made of a copper sleeve.

7. The roller / cam rolling friction pair testing device according to claim 1, characterized in that, A through hole for installing an input shaft (210) is opened at the center of the front end cover (27). A rolling bearing is installed on the front end surface, and an oil seal (211) is installed on the rear end surface. The front end cover (27) is connected to an oil seal cover (28) to fix the oil seal (211). The right end of the front end cover (27) is fixed to the working platform through an L-shaped bracket (212).

8. The roller / cam rolling friction pair testing device according to claim 1 or 7, characterized in that, The other end of the piston (214) is connected to the input shaft (210) through a ball spline sleeve (213). The input shaft (210) is designed as a stepped shaft. Ball grooves are symmetrically opened on the shaft head part of the input shaft (210), and the ball spline sleeve (213) is fitted through the ball grooves. The shaft body part of the input shaft (210) is used to limit the axial displacement of the rolling bearing installed on the front end cover (27). A key groove for installing a coupling is also opened on the shaft neck part of the input shaft (210).

9. A method for testing roller / cam rolling friction pairs, implemented using the roller / cam rolling friction pair testing device according to any one of claims 1-8, characterized in that, The method includes: S1. Test preparation stage: First, start the hydraulic energy supply system (1). Under the action of the hydraulic oil pressure, the cam (215) runs to the left limit state, and the cam (215) is in a tight state with the first roller (241) and the second roller (242). S2. Open the mechanical energy supply system (3) to provide the rotation speed and torque required for the rotation of the test system (2), and the input shaft (210) rotates. S3. Adjust the pressure of the hydraulic oil provided by the hydraulic energy supply system (1) to change the force exerted by the cam (215) on the first roller (241) and the second roller (242). By adjusting the rotation speed provided by the mechanical energy supply system (3), change the rotation speed of the input shaft (210) and the cam (215). S4. Measure the input torque of the motor (32) in the mechanical energy supply system (3) through a torque / rotation speed sensor (31).

10. A method for measuring the relative slip rate between a roller and a cam, implemented using the roller / cam rolling friction pair testing device according to any one of claims 1-8, characterized in that, The method is specifically as follows: The first roller (241) and the second roller (242) form a roller (24). First, non-reflective paint is applied to the surface of the roller (24), and then a reflective sheet is attached to the end of the roller (24). The actual rotation speed of the roller (24) is measured using an infrared velocimeter. The difference between the actual rotation speed and the theoretical rotation speed of the roller (24) is calculated to obtain the relative slip rate between the roller (24) and the cam (215).

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