A hydraulic motor plunger pair friction performance test device and method

Abstract

The present invention discloses a hydraulic motor plunger pair friction performance test device and method, belonging to the field of hydraulic motor testing. The device comprises a power source and a hydraulic motor plunger pair friction detection device, which are connected via a transmission device. The device comprises two guide rails, a sliding platform connected to the guide rails via sliders, and the sliding platform is slidably connected to a support platform. The sliding platform is provided with an inner curve test track, a columnar roller is provided on the inner curve test track, and a plunger pair loading structure is provided on the roller. The plunger pair loading structure comprises a plunger cylinder with a downward opening, which is vertically arranged on the sliding platform. An end cover is provided on the top of the plunger cylinder. A plunger to be tested that matches the roller is provided in the plunger cylinder. The plunger's bearing shell matches the roller. The end cover is provided with an oil inlet and is connected to a hydraulic valve station via a pipeline. The device has a simple structure, is easy to use, and has wide practical application.

Description

Technical Field

[0001] The invention relates to a hydraulic motor plunger pair friction performance test device and method, belonging to the field of hydraulic motor testing. Background Art

[0002] Hydraulic motors are widely used in engineering machinery, mining machinery and other fields. Among them, low-speed, high-torque hydraulic motors have high output torque, low speed, and can directly drive the load to work. Currently, the structures of low-speed, high-torque motors are mostly crankshaft swing cylinder type, crankshaft plunger type, energy balance type, and internal curve type. Among them, the internal curve type hydraulic motor is relatively small in size, has high output torque, and low pulsation, and should be more popular. The stability of the core component, the plunger pair, affects the service life of the motor. The plunger pair includes a rolling friction pair formed by the roller and the internal curve track, a reciprocating sliding friction pair formed by the plunger and the plunger hole, and a rotating sliding friction pair formed by the roller and the plunger bearing. Under low-speed water lubrication, it is difficult to form an effective lubricating film between the friction pairs of the internal curve motor, resulting in large leakage and rapid wear, resulting in low volumetric efficiency.

[0003] Therefore, a plunger pair test bench is required to study the various performance characteristics of the plunger under these specific operating conditions. The rolling friction pair formed by the roller and the internally curved track is rolling friction and has little impact on the overall motor. The focus is on the reciprocating sliding friction pair between the plunger and the plunger bore, and the rotating sliding friction pair between the roller and the plunger bearing. The reciprocating sliding friction pair between the plunger and the plunger bore, its structure, clearance, and material pairing, determine the offset load, wear, and leakage of the plunger and the plunger bore. The rotating sliding friction pair between the roller and the plunger bearing, whether it is a hydrostatic bearing structure, residual compression, or hydrodynamic lubrication, significantly affects the friction, wear, and leakage of this rotating sliding friction pair. Furthermore, the material pairing between the roller and the plunger bearing also significantly influences the performance of the plunger pair. Currently, there are few test devices and systems for the performance of the plunger pair in low-speed, high-torque, water-lubricated internally curved motors. Ensuring stable operation of the plunger pair, maintaining the motor's volumetric efficiency, and guaranteeing friction and wear performance over extended periods of operation are pressing challenges. Summary of the Invention

[0004] Purpose of the invention: In view of the shortcomings of the existing technology, a hydraulic motor plunger pair friction performance test device and method are provided, which can detect the working performance of the reciprocating sliding friction pair formed by the plunger and the plunger hole, that is, the plunger-cylinder hole pair; and can detect the working performance of the rotating sliding friction pair formed by the roller and the plunger bearing, which is hereinafter referred to as the roller-bearing pair.

[0005] Technical solution: To achieve the above technical objectives, the present invention provides a hydraulic motor plunger pair friction performance test device, comprising a power source and a hydraulic motor plunger pair friction detection device, wherein the power source and the hydraulic motor plunger pair friction detection device are connected via a transmission device;

[0006] The power source includes a motor base, on which a variable frequency motor is arranged, and an output shaft of the variable frequency motor is connected to a reducer;

[0007] The transmission device includes a mounting plate, an L-shaped support leg is provided at the bottom of the mounting plate, a bearing seat is provided on the mounting plate, a rotary crankshaft is matched with the bearing seat, the bottom of the rotary crankshaft passes through the mounting plate and is connected to the reducer via a synchronous pulley, and the top of the rotary crankshaft is connected to the connecting rod;

[0008] The hydraulic motor plunger pair friction detection device includes a supporting platform, two guide rails are provided in parallel on the top of the supporting platform, a sliding platform is connected to the guide rails via a slider, and the sliding platform is slidably connected to the supporting platform; one side of the sliding platform is connected to a connecting rod so that the sliding platform reciprocates left and right under the drive of the connecting rod, an inner curve test track is provided on the sliding platform, a columnar roller is provided on the inner curve test track, a plunger pair loading structure is provided on the roller, the plunger pair loading structure includes a plunger cylinder with a downward opening, the plunger cylinder is vertically arranged on the sliding platform, an end cover is provided on the top of the plunger cylinder, a plunger to be tested that matches the roller is provided in the plunger cylinder, a bearing bush of the plunger matches the roller, an oil inlet is provided in the middle of the end cover, and the oil inlet is connected to a hydraulic valve station through a pipeline;

[0009] A pressure sensor is provided on the pipeline at the end cover, which is connected to the oil inlet on the end cover through an oil pipe and measures the pressure in the plunger cylinder. A proportional relief valve is provided at the outlet of the hydraulic pump station.

[0010] Furthermore, side plates are provided on both sides of the bottom of the plunger cylinder to prevent the plunger from rotating; baffles are provided around the inner curve test track for storing working fluid, thereby forming a groove for storing working fluid with the inner curve test track, thereby simulating the rolling of the roller so that part of the working fluid is brought into the middle of the plunger and roller friction pair to start the lubrication effect, and the plunger and roller are immersed in the working fluid during work; the inner curve test track is made of high-strength engineering plastic, and there is soft and hard contact between the roller and the inner curve test track, thereby reducing the rolling friction of the roller to a minimum, and does not affect the rotational sliding friction between the roller and the bearing.

[0011] Furthermore, the inner curve test track is a curve in the straight direction, specifically a simulated cam curve, that is, a section of the inner curve track is projected on a straight line. The curve on the inner curve test track can make the plunger and the roller subjected to lateral force, thereby simulating the working state of the plunger being overloaded in the plunger cylinder; it can simulate the working conditions of the plunger-cylinder hole pair and the roller-bearing pair, and can also simulate the friction and wear performance of the two plunger pairs under lubrication of different working media.

[0012] Furthermore, the reciprocating sliding of the plunger in the plunger cylinder simulates the motion condition of the inner curve motor plunger, that is, the motion condition of the plunger-cylinder bore pair; at the same time, the power source drives the inner curve test track and the roller to roll in the plunger's bearing by driving the sliding platform to move back and forth, simulating the motion condition of the plunger and roller friction pair, that is, the motion condition of the roller-bearing pair.

[0013] Furthermore, during the motion working condition of the plunger-cylinder pair, different clearances, different materials, different pressures, different speeds and different surface treatment processes between the plunger and the plunger cylinder are adjusted to simulate different friction and wear performances and leakage change laws; by simulating the influence of different sealing structure forms, parameters and plunger-cylinder pair clearances and plunger-cylinder hole surface roughness of the plunger-cylinder pair with a sealing ring sealing structure on the performance of the plunger-cylinder pair.

[0014] Furthermore, the plunger cylinder is vertically arranged through a bracket, and the bracket includes a vertical plate arranged vertically on the support platform, and a horizontal plate is provided on the vertical plate. The plunger cylinder is kept in a fixed position by the horizontal plate.

[0015] Furthermore, the rollers were made to roll in plunger bearings of different structures, and the leakage of the hydrostatically supported roller-bearings and the residually pressed roller-bearings was measured. The wear morphology changes of the hydrostatically supported roller-bearings and the residually pressed roller-bearings were observed after the test, thereby simulating the working performance of the hydrostatically supported roller-bearings, hydrodynamically lubricated roller-bearings, and residually pressed roller-bearings.

[0016] In the test of the hydrostatically supported roller-bearing pair, the structural parameters of the hydrostatically supported roller-bearing pair include: the diameter of the fixed damper is Dr, the length Lr, the plunger diameter Dz, and the bearing cavity width W. According to the design calculation results, the main shaft bearing and roller of the corresponding size are first processed, and then installed in the plunger cylinder 12. The roller 19 is subjected to rolling friction in the bearing by the inner curve test track 10, and at the same time, the upper cavity of the plunger 18 is subjected to liquid pressure, thereby realizing the simulation of the friction and wear test of the roller-bearing pair; since the projected area of ​​the residual compression type plunger bearing in the axial direction is smaller than the plunger bottom area, and the projected area of ​​the hydrostatically supported plunger bearing in the axial direction is larger than the plunger bottom area, the two are only different in the friction pair structure, so the process and method of the residual compression type roller-bearing pair test are the same as the test process of the hydrostatically supported roller-bearing pair, and the bearing cavity width in the residual compression type roller-bearing pair is Ws;

[0017] In the hydrodynamic lubrication roller-bearing pair test, the structural parameters of the roller-bearing pair during hydrodynamic lubrication include: the roller-bearing radius clearance is machined to Rzw-Rg, the roller rolling speed is the rolling friction speed of the roller in the bearing, which is determined by the reciprocating speed of the inner curve test track and achieved by adjusting the speed of the variable frequency motor. By replacing rollers and plungers made of different materials, different friction and wear properties can be tested.

[0018] Furthermore, the relative motion speed adjustment process of the friction pair in the movement of the plunger-cylinder bore pair and the roller-bearing pair is: by adjusting the frequency converter to control the variable frequency motor, and then controlling the output speed of the reducer to drive the synchronous pulley to make the rotating crankshaft move at different speeds, and then drive the connecting rod and the sliding platform to move, and the sliding platform drives the inner curve test track to move, and finally realize the reciprocating sliding speed of the plunger in the plunger cylinder, and at the same time realize the rolling speed of the roller in the plunger bearing, simulating the working conditions of the plunger-cylinder bore pair and the roller-bearing pair under different pressures and different speeds.

[0019] Furthermore, a proportional relief valve is used to adjust the working pressure of the working medium in the plunger cylinder cavity, and the working liquid is adjusted to make the plunger subject to liquid pressure, thereby ensuring that the roller is pressed tightly against the inner curve test guide rail 10; the working medium in the plunger cylinder cavity can be pure water, emulsion, water glycol, anti-wear hydraulic oil, and seawater, simulating the friction and wear performance of the plunger-cylinder pair and the roller-bearing pair under the lubrication of liquids with different viscosities.

[0020] A hydraulic motor plunger pair friction and wear performance test device, the steps are as follows:

[0021] a. First, according to the test purpose, assemble the processed plunger, roller, and plunger cylinder and install them on the horizontal plate. Install the inner curve test track on the sliding platform and add working fluid into the liquid reservoir formed by the inner curve test track and its four baffles.

[0022] b. Turn on the power and start the frequency converter to control the frequency conversion motor to rotate. The frequency conversion motor drives the output shaft of the reducer through the coupling. The reducer drives the synchronous pulley to drive the rotary crankshaft to rotate. The rotary crankshaft drives the connecting rod to make the sliding platform slide back and forth on the guide rail.

[0023] c. When the inner curve test track moves back and forth with the sliding platform, it pushes the plunger to reciprocate in the plunger cylinder, realizing the friction and wear test simulation of the plunger-cylinder bore pair; at the same time, the interaction between the inner curve test track and the roller causes the roller to roll in the plunger bearing, realizing the friction and wear test simulation of the roller-bearing pair;

[0024] d. Start the hydraulic pump station to supply fluid to the plunger cylinder cavity, adjust the pressure of the proportional relief valve, and control the pressure of the working fluid in the plunger cylinder. At the same time, the pressure in the plunger cylinder cavity is measured and recorded by the pressure sensor, which can realize the friction and wear test of the plunger-cylinder pair and the roller-bearing pair under different pressures;

[0025] e. By adjusting the frequency converter to control the output speed of the variable frequency motor, the reciprocating speed of the plunger in the plunger cylinder and the rolling speed of the roller in the bearing are controlled in sequence through the reducer, synchronous pulley, rotary crankshaft, connecting rod, and sliding platform on the inner curve test track, thereby realizing friction and wear tests of the plunger-cylinder pair and the roller-bearing pair at different movement speeds;

[0026] f. During the test, the leakage of the plunger-cylinder pair and the roller-bearing pair is collected in the liquid collection tank, and the leakage of the friction pair is recorded during the test;

[0027] After the test, the plunger cylinder, plunger and roller are removed. By measuring the surface profile curve fluctuation, surface roughness, microscopic wear marks and microscopic three-dimensional morphology of the corresponding friction surfaces of the plunger-cylinder bore pair and the roller-bearing pair, and combining the volume of working liquid collected in the liquid collection tank during the test, the friction and wear test performance of the plunger-cylinder bore pair and the roller-bearing pair under different pressures and speeds are analyzed, and then the working performance and wear failure mechanism of the friction pair are evaluated.

[0028] Beneficial Effects: This invention can conduct friction and wear tests on plunger pairs under different operating conditions, simulating friction and wear tests on plunger-cylinder and roller-bearing pairs under varying pressures, speeds, structural forms, and parameters. By processing different friction pair materials, the optimal material pairings for plunger-cylinder and roller-bearing pairs can be studied. The leakage of the friction pairs can be measured, and the friction performance of the roller and plunger bearing under dry friction conditions can also be studied. With its simple structure and convenient operation, the invention provides an experimental basis and relevant theoretical reference for plunger pair design and friction and wear performance research.

[0029] This device fits the actual working conditions of the plunger-cylinder bore pair and the roller bearing pair, and truly simulates the plunger-cylinder bore pair and the roller bearing pair of the internal curve hydraulic motor, solving the difficult problem of being unable to measure the friction working performance of these two friction pairs. By designing the relevant plunger, plunger bore, plunger bearing, roller structure and materials, the friction and wear performance under different working conditions is simulated, and then the optimal friction pair structure is selected for use in the motor, providing a research basis and technical means for the design and research of the internal curve motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A front view of the friction and wear performance test device for the hydraulic motor plunger pair of the present invention;

[0031] Figure 2 AA cross-sectional schematic diagram of the hydraulic motor plunger pair friction and wear performance testing device of the present invention.

[0032] Figure 3 Schematic diagram of plunger bearing, dynamic pressure lubrication type, static pressure support type and residual pressure type roller-bearing structure.

[0033] In the figure, 1-frequency conversion motor, 2-motor base, 3-reducer, 4-mounting plate, 5-synchronous pulley, 6-support platform, 7-guide rail, 8-slider, 9-sliding platform, 10-inner curve test track, 11-cross plate, 12-plunger cylinder, 13-end cover, 14-L-shaped support leg, 15-bearing seat, 16-rotating crankshaft, 17-connecting rod, 18-plunger, 19-roller, 20-liquid collection tank, 21-pressure sensor. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings.

[0035] like Figure 1 As shown, a hydraulic motor plunger pair friction and wear performance test device is characterized in that: it includes a variable frequency motor 1, the variable frequency motor 1 is mounted on the motor base 2, and the variable frequency motor 1 is connected to the reducer 3 through a coupling, the reducer 3 and the bearing base 15 are mounted on the mounting plate 4, the output main shaft of the reducer 3 is connected to the rotary crankshaft 16 through the synchronous pulley 5 and transmits the power, the mounting plate 4, the motor base 2, and the L-shaped support leg 14 are assembled together and fixed on the mounting table; the rotary crankshaft 16 is mounted in the bearing base 15 and connected to the sliding platform 9 through the connecting rod 17, and the two ends of the connecting rod 7 are connected to the sliding platform 9 and the rotary crankshaft 16 through hinges consisting of bearings and pins;

[0036] like Figure 2 As shown, the inner curve test track 10 is surrounded by baffles for storing working fluid, and the inner curve test track 10 is installed on the sliding platform 9, and the sliding platform 9 is fixed to the slider 8 by bolts, and then the slider 8 is installed on the guide rail 7, and the guide rail 7 is installed on the supporting platform 6 by bolt connection, and the supporting platform 6 is fixed on the mounting platform, and a cross plate 11 is installed on the vertical plate, and the plunger cylinder 12 and the end cover 13 are installed on the cross plate 11 by bolt connection, and the roller 19 is installed in the bearing of the plunger 18. A radial through hole cavity is provided in the plunger cylinder 12, and the plunger 18 is integrally installed in the through hole cavity of the plunger cylinder 12. Side plates are provided on both sides of the bottom of the plunger cylinder 12 to prevent the plunger from rotating. The pressure sensor 21 for measuring the pressure in the plunger cylinder 12 is connected to the inlet of the end cover 13 through an oil pipe, and the proportional relief valve is used to set the test pressure in the through hole cavity of the plunger cylinder 12.

[0037] Figure 3As shown, one end of the plunger 18 is processed with a semicircular structure for accommodating a roller 19, which is a bearing bush.

[0038] A hydraulic motor plunger pair friction and wear performance test method, the working steps are as follows:

[0039] a) First, according to the test objectives, assemble the processed plunger 18, roller 19, and plunger cylinder 12 and install them on the cross plate 11. Install the inner curve test track 10 on the sliding platform 9. Add working fluid to the reservoir formed by the inner curve test track 10 and its four baffles;

[0040] b) Turn on the power supply and start the frequency converter to control the frequency conversion motor 1 to rotate. The frequency conversion motor 1 drives the output shaft of the reducer 3 to rotate through the coupling. The reducer 3 drives the synchronous pulley 5 to rotate the rotary crankshaft 16. The rotary crankshaft 16 drives the connecting rod 17 to make the sliding platform 9 slide back and forth on the guide rail 7;

[0041] c) When the inner curve test track 10 reciprocates with the sliding platform 9, it pushes the plunger 18 to reciprocate in the plunger cylinder 12, realizing a friction and wear test simulation of the plunger-cylinder bore pair; at the same time, during operation, the inner curve test track 10 interacts with the roller 19, causing the roller 19 to roll in the bearing of the plunger 18, realizing a friction and wear test simulation of the roller-bearing pair;

[0042] d) Start the hydraulic pump station to supply fluid to the plunger cylinder 12 cavity, adjust the pressure of the proportional relief valve, and control the pressure of the working fluid in the plunger cylinder 12. At the same time, the pressure in the plunger cylinder 12 cavity is measured and recorded by the pressure sensor 21, so as to realize the friction and wear test of the plunger-cylinder bore pair and the roller-bearing pair under different pressures;

[0043] e) By adjusting the frequency converter to control the output speed of the variable frequency motor 1, the reciprocating speed of the plunger 18 in the plunger cylinder 12 and the rolling speed of the roller 19 in the bearing are controlled by the inner curve test track 10 through the reducer 3, synchronous pulley 4, rotary crankshaft 16, connecting rod 17, and sliding platform 9, respectively, to achieve friction and wear tests of the plunger-cylinder pair and the roller-bearing pair at different movement speeds;

[0044] f) During the test, the leakage of the plunger-cylinder pair and the roller-bearing pair is collected in the liquid collection tank 20, and the leakage of the friction pair during the test is recorded;

[0045] g) After the test, the plunger cylinder 12, plunger 18 and roller 19 are removed. By measuring the surface profile curve fluctuation, surface roughness, microscopic wear marks, and microscopic three-dimensional morphology of the corresponding friction surfaces of the plunger-cylinder bore pair and the roller-bearing pair, and combining the volume of fluid collected in the liquid collection tank 20 during the test, the friction and wear test performance of the plunger-cylinder bore pair and the roller-bearing pair at different pressures and speeds is analyzed, and the working performance and wear failure mechanism of the friction pair are evaluated.

[0046] Furthermore, the inner curve test track 10 is made of high-strength engineering plastic, and the roller 19 and the inner curve test track 10 are in soft and hard contact. During the test, the rolling friction of the roller 19 is reduced to a minimum, thereby not affecting the rotational sliding friction between the roller 19 and the bearing.

[0047] Furthermore, the working medium of the hydraulic pump station can use pure water, emulsion, water glycol, anti-wear hydraulic oil, and seawater, and then study the friction and wear performance of the plunger-cylinder pair and the roller-bearing pair under lubrication of liquids of different viscosities, and analyze the influence of liquid viscosity on the lubrication of the plunger-cylinder pair and the roller-bearing pair.

[0048] Furthermore, the plunger-cylinder bore pair can be divided into two types in the test: (1) a plunger-cylinder bore pair with a gap sealing structure. In the test, the friction pair gap between the plunger and the plunger cylinder can be set to simulate the friction wear performance and leakage change law of the plunger-cylinder bore pair under different gaps. At the same time, the plunger and the plunger cylinder can also be processed using different materials, processing techniques, and surface treatment technologies in the test to simulate the friction wear performance of the plunger-cylinder bore pair under different material pairings, so as to select the best material pairing for the design of the plunger-cylinder bore pair; (2) a plunger-cylinder bore pair with a sealing ring sealing structure. In the test, a sealing ring is set on the outer circle of the plunger 18. The structure of the sealing ring can include lip seal, step seal, Gley ring, pan seal, etc. The influence of sealing rings of different structural forms on the friction wear and sealing performance of the plunger-cylinder bore pair is studied. At the same time, the influence of the plunger-cylinder bore pair gap and the roughness of the plunger cylinder bore surface on the performance of the plunger-cylinder bore pair can also be studied.

[0049] Furthermore, the working performance of the roller-bearing pair structures of the static pressure support type, the dynamic pressure lubrication type, and the residual pressure type can be simulated in the test.

[0050] (i) In the hydrostatic bearing roller-bearing pair test, the effects of different hydrostatic bearing structural parameters, bearing cavity shapes, and fixed damping on the friction, wear, and leakage of the roller-bearing pair can be studied to determine the optimal hydrostatic bearing roller-bearing pair structure. The effect of the material pairing between the roller 19 and the plunger 18 bearing on the friction and wear performance can also be studied.

[0051] (ii) In the hydrodynamic lubrication roller-bearing pair test, by machining the bearing and roller dimensions of the plunger 18, the friction and wear performance of the hydrodynamic lubrication roller-bearing pair under different radial clearances, different roller speeds, and different bearing and roller 19 material pairings can be simulated, and the optimal hydrodynamic lubrication roller-bearing pair structural parameters and materials can be determined.

[0052] During the test, a hydraulic motor plunger pair friction and wear performance test device can independently simulate the friction and wear tests of the plunger-cylinder pair or the roller-bearing pair under different pressures, different speeds, different material combinations and different structural parameters, and can also simultaneously simulate the friction and wear tests of the plunger-cylinder pair and the roller-bearing pair under different pressures, different speeds, different material combinations and different structural parameters.

Claims

1. A hydraulic motor plunger pair friction performance test device, characterized by: It includes a power source and a hydraulic motor plunger pair friction detection device, and the power source and the hydraulic motor plunger pair friction detection device are connected through a transmission device; The power source comprises a motor base (2), a variable frequency motor (1) is arranged on the motor base (2), and an output shaft of the variable frequency motor (1) is connected to a reducer (3); The transmission device includes a mounting plate (4), an L-shaped support leg (14) is provided at the bottom of the mounting plate (4), a bearing seat (15) is provided on the mounting plate (4), a rotating crank shaft (16) is matched with the bearing seat (15), the bottom of the rotating crank shaft (16) passes through the mounting plate (4) and is connected to the reducer (3) through a synchronous pulley (5), and the top of the rotating crank shaft (16) is connected to the connecting rod (17); The hydraulic motor plunger pair friction detection device comprises a supporting platform (6), two guide rails (7) are arranged in parallel on the top of the supporting platform (6), a sliding platform (9) is connected to the guide rail (7) through a slider (8), and the sliding platform (9) is slidably connected to the supporting platform (6); one side of the sliding platform (9) is connected to a connecting rod (17) so that the sliding platform (9) moves back and forth under the drive of the connecting rod (17), an inner curve test track (10) is arranged on the sliding platform (9), and a columnar roller (19) is arranged on the inner curve test track (10). A plunger auxiliary loading structure is provided on the roller (19), and the plunger auxiliary loading structure includes a plunger cylinder (12) with an opening facing downward, the plunger cylinder (12) is vertically arranged on the sliding platform (9), an end cover (13) is provided on the top of the plunger cylinder (12), a plunger (18) to be tested that matches the roller (19) is provided in the plunger cylinder (12), a bearing bush of the plunger (18) matches the roller (19), and a bearing bush of the plunger (18) matches the arc surface of the upper surface of the roller (19), an oil inlet is opened in the middle of the end cover (13), and the oil inlet is connected to a hydraulic valve station through a pipeline; A pressure sensor (21) is provided on the pipeline at the end cover (13). The pressure sensor (21) is connected to the oil inlet on the end cover (13) through an oil pipe and measures the pressure in the plunger cylinder (12). A proportional overflow valve is provided at the outlet of the hydraulic pump station.

2. The friction performance test device for a hydraulic motor plunger pair according to claim 1, characterized in that: Side plates are provided on both sides of the bottom of the plunger cylinder (12) to prevent the plunger (18) from rotating; baffles are provided around the inner curve test track (10) for storing working fluid, thereby forming a groove for storing working fluid with the inner curve test track (10), thereby simulating the roller (19) bringing part of the working fluid into the middle of the friction pair of the plunger (18) and the roller (19) when rolling to start lubrication, and the plunger (18) and the roller (19) are always immersed in the working fluid during operation; the inner curve test track (10) is made of high-strength engineering plastic, and there is soft and hard contact between the roller (19) and the inner curve test track (10), thereby reducing the rolling friction of the roller (19) to a minimum, and does not affect the rotational sliding friction between the roller (19) and the bearing.

3. The friction performance test device for a hydraulic motor plunger pair according to claim 1, characterized in that: The inner curve test track (10) is a curve in the straight direction, specifically a simulated cam curve, that is, a section of the inner curve track is projected on a straight line. The curve on the inner curve test track (10) can make the plunger (18) and the roller (19) be subjected to lateral force, thereby achieving a working state where the plunger is overloaded in the plunger cylinder; it can simulate the working conditions of the plunger-cylinder hole pair and the roller-bearing pair, and can also simulate the friction and wear performance of the two plunger pairs under lubrication of different working media.

4. The friction performance test device for a hydraulic motor plunger pair according to claim 1, characterized in that: The reciprocating sliding of the plunger (18) in the plunger cylinder (12) simulates the motion condition of the inner curve motor plunger, that is, the motion condition of the plunger-cylinder bore pair; at the same time, the power source drives the inner curve test track (10) and the roller (19) to roll in the bearing of the plunger (18) by driving the sliding platform (9) to move back and forth, simulating the motion condition of the plunger and roller friction pair, that is, the motion condition of the roller-bearing pair.

5. The friction performance test device for a hydraulic motor plunger pair according to claim 4, characterized in that: During the motion working condition of the plunger-cylinder pair, different gaps, different materials, different pressures, different speeds and different surface treatment processes between the plunger (18) and the plunger cylinder (12) are adjusted to simulate different friction and wear properties and leakage change laws.

6. The hydraulic motor plunger pair friction performance test device according to claim 1, characterized in that: The plunger cylinder (12) is vertically arranged through a bracket, and the bracket includes a vertical plate arranged vertically on the support platform, and a horizontal plate (11) is provided on the vertical plate. The plunger cylinder (12) is kept in a fixed position by the horizontal plate (11).

7. The friction performance test device for a hydraulic motor plunger pair according to claim 1, characterized in that: The roller (19) is made to roll in the plunger (18) bearings of different structures, and the leakage of the hydrostatic bearing roller-bearing and the residual pressure roller-bearing is measured. The wear morphology change of the hydrostatic bearing roller-bearing and the residual pressure roller-bearing surface after the test is observed, thereby simulating the working performance of the hydrostatic bearing roller-bearing, the dynamic pressure lubrication roller-bearing, and the residual pressure roller-bearing pair structure; wherein: In the test of the hydrostatically supported roller-bearing pair, the structural parameters of the hydrostatically supported roller-bearing pair include: the diameter of the fixed damper is Dr, the length Lr, the plunger diameter Dz, and the bearing cavity width W. According to the design calculation results, the main shaft bearing and roller of corresponding size are first processed and installed in the plunger cylinder (12). The roller (19) is subjected to rolling friction in the bearing by the inner curve test track (10), and the upper cavity of the plunger (18) is subjected to the liquid pressure, thereby realizing the simulation of the friction and wear test of the roller-bearing pair. Since the projected area of ​​the residual compression type plunger bearing in the axial direction is smaller than the plunger bottom area, and the projected area of ​​the hydrostatically supported plunger bearing in the axial direction is larger than the plunger bottom area, the two are only different in the friction pair structure, so the process and method of the residual compression type roller-bearing pair test are exactly the same as the test process of the hydrostatically supported roller-bearing pair. The bearing cavity width in the residual compression type roller-bearing pair is Ws. In the hydrodynamic lubrication type roller-bearing pair test, the structural parameters of the roller-bearing pair during hydrodynamic lubrication include: the roller-bearing radius clearance is made Rzw-Rg by machining, the rolling speed of the roller (19) is the rolling friction speed of the roller (19) in the bearing, and the speed is determined by the reciprocating speed of the inner curve test track (10) and is achieved by adjusting the speed of the variable frequency motor (1). By replacing the roller (19) and the plunger (18) processed by different materials, different friction and wear properties can be tested.

8. The friction performance test device for a hydraulic motor plunger pair according to claim 1, characterized in that: The relative motion speed adjustment process of the friction pair in the movement of the plunger-cylinder hole pair and the roller-bearing shell pair is as follows: by adjusting the frequency converter to control the variable frequency motor (1), and then controlling the output speed of the reducer (3) to drive the synchronous pulley (5) to make the rotating crankshaft (16) move at different speeds, and then drive the connecting rod (17) and the sliding platform (9) to move, and the sliding platform (9) drives the inner curve test track (10) to move, and finally realizes the reciprocating sliding speed of the plunger (18) in the plunger cylinder (12), and at the same time realizes the rolling speed of the roller (19) in the plunger (18) bearing shell, simulating the working conditions of the plunger-cylinder hole pair and the roller-bearing shell pair under different pressures and different speeds.

9. The hydraulic motor plunger pair friction performance test device according to claim 1, characterized in that: The working pressure of the working medium in the cavity of the plunger cylinder (12) is adjusted by using a proportional relief valve, and the working liquid is adjusted so that the plunger (18) is subjected to liquid pressure, thereby ensuring that the roller (19) is pressed tightly against the inner curve test track (10); the working medium in the cavity of the plunger cylinder (12) can be pure water, emulsion, water glycol, anti-wear hydraulic oil, or seawater, simulating the friction and wear performance of the plunger-cylinder pair and the roller-bearing pair under the lubrication of liquids with different viscosities.

10. An experimental method using the hydraulic motor plunger pair friction and wear performance testing device according to claim 6, characterized in that The steps are: a. First, according to the test purpose, the processed plunger (18), roller (19), and plunger cylinder (12) are assembled and installed on the horizontal plate (11), the inner curve test track (10) is installed on the sliding platform (9), and the working liquid is added to the liquid reservoir formed by the inner curve test track (10) and its four baffles; b. Turn on the power supply and start the frequency converter to control the frequency conversion motor (1) to rotate. The frequency conversion motor (1) drives the output shaft of the reducer (3) to rotate through the coupling. The reducer (3) drives the synchronous pulley (5) to drive the rotary crankshaft (16) to rotate. The rotary crankshaft (16) drives the connecting rod (17) to make the sliding platform (9) slide back and forth on the guide rail (7); c. When the inner curve test track (10) moves back and forth with the sliding platform (9), the plunger (18) is pushed to move back and forth in the plunger cylinder (12), thereby realizing a friction and wear test simulation of the plunger-cylinder bore pair; at the same time, during operation, the inner curve test track (10) and the roller (19) interact with each other to cause the roller (19) to roll in the bearing of the plunger (18), thereby realizing a friction and wear test simulation of the roller-bearing pair; d. Start the hydraulic pump station to supply fluid to the cavity of the plunger cylinder (12), adjust the pressure of the proportional relief valve, and control the pressure of the working fluid in the plunger cylinder (12). At the same time, the pressure in the cavity of the plunger cylinder (12) is measured and recorded by the pressure sensor (21), so as to realize the friction and wear test of the plunger-cylinder pair and the roller-bearing pair under different pressures; e. By adjusting the output speed of the variable frequency motor (1) controlled by the frequency converter, the reciprocating speed of the plunger (18) in the plunger cylinder (12) and the rolling speed of the roller (19) in the bearing are controlled by the inner curve test track (10) through the reducer (3), the synchronous pulley (5), the rotary crankshaft (16), the connecting rod (17), and the sliding platform (9), thereby realizing the friction and wear test of the plunger-cylinder hole pair and the roller-bearing pair at different movement speeds; f. During the test, the leakage of the plunger-cylinder pair and the roller-bearing pair is collected in the liquid collection tank (20), and the leakage of the friction pair during the test is recorded; After the test, the plunger cylinder (12), plunger (18) and roller (19) are disassembled. By measuring the surface profile curve fluctuation, surface roughness, microscopic wear marks and microscopic three-dimensional morphology of the corresponding friction surfaces of the plunger-cylinder hole pair and the roller-bearing pair, and combining the volume of the working liquid collected in the liquid collection tank (20) during the test, the friction and wear test performance of the plunger-cylinder hole pair and the roller-bearing pair under different pressures and different speeds is analyzed, and then the working performance and wear failure mechanism of the friction pair are evaluated.

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