High-pressure axial plunger pump friction pair oil film characteristic testing device and method

Abstract

The invention discloses a high-pressure axial plunger pump friction pair oil film characteristic testing device and method, and belongs to the technical field of hydraulic elements. Comprising a motor serving as a power source, an external oil source system, a data acquisition card and an industrial personal computer, the motor is connected with a flow distribution pair testing part and a plunger pair testing part through a main shaft, in a flow distribution pair testing device, the actual pump operation condition is simulated through a flow distribution pair swash plate assembly capable of replacing different inclination angles, and the testing precision of a flow distribution pair oil film is improved; in the plunger pair testing device, a plunger pair swash plate with different inclination angles and dynamic balance balancing and a symmetrically arranged long plunger body plunger pair structure can be replaced, and the whole device is connected with a flow distribution pair testing device through a main shaft and a flow distribution piece, so that two friction pairs can be tested at the same time; the plunger pair testing device is simple and reliable in overall structure, parts are convenient to replace, and the detection cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic components, and in particular relates to a device and method for testing the oil film characteristics of a friction pair of a high-pressure axial piston pump. Background Art

[0002] The axial piston pump is one of the most important power components in the field of fluid transmission and control. It has been widely and deeply used in all walks of life. With the continuous development of industrial technology, various application fields have put forward urgent demands for higher working pressure and larger displacement for axial piston pumps. The distribution pair and the plunger pair are the core friction pairs for the axial piston pump to realize its basic functions. The oil film formed by the distribution pair and the plunger pair during the working process has a decisive influence on the high-speed, high-pressure and high-efficiency performance of the axial piston pump. The oil film at the distribution pair is mainly an annular sealing belt between the cylinder body and the distribution plate, which is formed by the relative movement between the distribution plate and the cylinder body. Its main function is to seal the high-pressure oil port of the plunger pump and the high-pressure oil in the plunger cavity, and to generate support force for the cylinder body. The oil film at the plunger pair is mainly a cylindrical sealing belt between the plunger and the cylinder body, which is formed by the relative movement of the plunger and the cylinder body hole. Its main function is to form a periodically changing plunger cavity. The volume of the cavity decreases to discharge oil, and vice versa to absorb oil. At present, there are mainly the following test devices for testing the oil film at the distribution pair and the plunger pair: 1. Test device based on the whole pump: In this type of test device, the prototype pump is directly used for testing. Harbin Institute of Technology has developed such a test device. The test device directly uses the prototype pump for testing, so the test results of the oil film at the corresponding friction pair are more accurate, but the pressure and displacement tested by this test device are relatively small, and it has little reference value for the development of high-pressure and large-displacement axial piston pumps; 2. Test device based on model pump concept: An existing test device of this type can measure the friction pair inside the pump without changing the structure of the axial piston pump, which is very close to the actual working condition. However, this type of test device must use wireless telemetry technology, which makes the overall cost of the test device expensive, and requires the sensor line to be cut off, so it cannot test the oil film thickness with high accuracy requirements; 3. Test device based on relative motion reversal: This type of test device is based on the idea of ​​relative motion between the swash plate / slipper-plunger assembly and the cylinder block / distributor plate. Through the principle of motion similarity, the rotating swash plate drives the plunger to reciprocate and the rotating friction plate (distributor plate) fixes the cylinder block, which is close to the dynamic behavior of the plunger pair in the real pump. However, the pressure and speed of the existing test device are far lower than the rated value of the actual pump; or the sensor is installed on the fixed cylinder block and distribution plate assembly, but this method poorly simulates the actual working conditions of the prototype pump. Summary of the invention

[0003] In view of the shortcomings of the prior art, a device and method for testing the oil film characteristics of the friction pair of a high-pressure axial piston pump are provided. The device allows the pressure and displacement to be greater than or equal to the rated speed and rated pressure commonly used in current industrial pumps. The device can simultaneously measure the oil film at the distribution pair and the plunger pair, as well as the working speed and the oil pressure in the plunger cavity, and the parts are easy to replace.

[0004] In order to achieve the above-mentioned purpose, the present invention discloses a high-pressure axial piston pump friction pair oil film characteristic test device, comprising: a motor as a power source, an external oil source system, a data acquisition card and an industrial computer, the motor is connected to a horizontally arranged main shaft through a coupling, a left end cover, a distribution pair test part and a plunger pair test part are arranged on the upper side of the main shaft from left to right, a distribution piece is arranged between the distribution pair test part and the plunger pair test part, a through hole for accommodating the main shaft is arranged at the center of the distribution piece, a bearing seat for installing a sliding bearing is arranged on the left side of the through hole of the distribution piece, and a swash plate seat is connected to the right side of the through hole of the distribution piece through a tapered roller bearing; wherein the main shaft and the left end cover are provided with a plurality of A cylindrical roller bearing movable connection is provided which is pressed by a shaft end pressure plate, the cylindrical roller bearing is fixedly connected to the shaft shoulder of the main shaft through a shaft elastic retaining ring, and the shaft end pressure plate is fixed to the left side of the left end cover through a pressure plate screw; wherein a distribution pair housing assembly is provided on the outside of the distribution pair test part, a plunger pair housing assembly is provided on the outside of the plunger pair test part, the distribution pair test part is integrally connected to the plunger pair test part through a distribution piece, and a plurality of eddy current displacement sensors are respectively provided on the oil distribution plate and the cylinder body; the pressure sensor, the temperature sensor in the external oil source system and the eddy current displacement sensor in the test device are all connected to the data acquisition card, and the data acquisition card is connected to the industrial computer; The distribution pair test part includes a distribution pair swash plate and a rotor sleeved on the main shaft. A variable diameter through hole is provided in the rotor axial direction. The front half of the variable diameter through hole matches the main shaft through a spline, and the aperture of the rear half of the variable diameter through hole is increased. A distribution pair spring is provided between the inner wall of the through hole and the main shaft. A spherical surface is provided at the right end of the rotor. The rotor fits the spherical surface with the spherical surface of the oil separator through the spherical surface. The oil separator is fixed on the distribution piece through a locating pin. The oil separator is fixed. The rotor rotates under the drive of the main shaft. The oil separator and the rotor are lubricated by oil. Three evenly distributed eddy current displacement sensors are installed on the outer expansion edge of the oil separator. A sensor measuring plate for receiving eddy current signals is fixed on the right end of the rotor by three countersunk screws. The relative displacement between the rotor and the oil separator is detected by the three eddy current displacement sensors, so as to judge the thickness information of the distribution pair oil film according to the displacement of the rotor relative to the oil separator. The distribution pair swash plate is fixed to the right side of the left end cover by the upper and lower distribution pair swash plate cylindrical pins. The rotor surrounds The main shaft is provided with 9 plunger cavities, which are embedded in the rotor bushing. Each rotor bushing is provided with a plunger body. The plunger body is hinged with a distribution pair sliding shoe through a ball head end to form an assembly. The assembly of the plunger body and the distribution pair sliding shoe is pressed by the disc spring on the right inclined surface of the distribution pair inclined plate through the joint action of the pressure plate, the distribution pair ball joint, the disc spring and the adjusting gasket in sequence; two rotor washers are sleeved on the main shaft in the rear half of the rotor reducing hole, and the two rotor washers are respectively arranged at both ends of the distribution pair spring, one rotor washer is arranged between the middle spline end of the main shaft and the distribution pair spring, and the other rotor washer is arranged between the distribution pair spring and the bearing seat, wherein a hole elastic retaining ring is also arranged between the rotor washer and the bearing seat; the spring force of the distribution pair spring acts on the hole elastic retaining ring fixed on the rotor, thereby causing the spring force to act on the rotor, so that the rotor is pressed against the oil separator; during operation, the rotor and the oil separator are fitted together, so that the displacement between the two is equal to the oil film thickness being detected; The plunger auxiliary test part includes a plunger auxiliary swash plate and a cylinder body that match the swash plate seat. The main shaft is connected and driven with the swash plate seat axis through the end spline. The swash plate seat and the plunger auxiliary swash plate are fixed by two upper and lower plunger auxiliary swash plate cylindrical pins. The left side of the cylinder body matches the inclined surface of the plunger auxiliary swash plate. A preload support part is provided at the center of the cylinder body. The preload support part includes a spring hole for accommodating a plunger auxiliary spring. A shoulder for fixing the plunger auxiliary spring is provided in the spring hole. A plunger auxiliary ball joint is provided at the left end of the plunger auxiliary spring through a spring gasket. The right end of the plunger auxiliary spring is fixed to the shoulder through a spring gasket. Two symmetrically arranged cylinder plunger cavities are opened in the cylinder body around the central spring hole. The tails of the two cylinder plunger cavities are respectively provided with two oil ports connected to the external oil source system pipeline. A long plunger body is provided through the cylinder bushing, and the left end of the long plunger body is a ball head end. The long plunger body is hinged with a plunger auxiliary sliding shoe through the ball head end to form an assembly. The assembly composed of the long plunger body and the plunger auxiliary sliding shoe is pressed against the inclined surface of the plunger auxiliary inclined plate by the spring force of the plunger auxiliary spring by adjusting the spring gaskets of different thicknesses under the joint action of the symmetrical pressure plate, the plunger auxiliary ball joint, the plunger auxiliary spring and the spring gasket; two pairs of eddy current displacement sensors with an angle of 90° to each other and an axial distance are provided on the side wall of a cylinder plunger cavity of the cylinder body, and the two pairs of eddy current displacement sensors are used to detect the posture change of the long plunger body in the cylinder plunger cavity, and the oil film thickness of the plunger auxiliary is judged by the detected posture of the long plunger body in the cylinder plunger cavity.

[0005] Furthermore, the motor is fixed on the ground, the motor transmits power to the main shaft through a coupling and a flat key, and the main shaft transmits power to the rotor and the swash plate seat in sequence through a spline.

[0006] Further, the distribution pair housing assembly includes: a left flange, a reinforcing rib, a distribution pair oil drain port pressure plate, an inner hexagon screw, a bolt, an elastic gasket, a nut, a distribution piece left O-ring, a distribution pair middle flange, a distribution pair housing, a left end cover locating pin, and a left end cover O-ring; the left flange, the reinforcing rib, the distribution pair oil drain port pressure plate and the distribution pair middle flange are welded to the distribution pair housing by welding; a distribution pair oil drain port pressure plate is provided in the middle of the distribution pair housing, the left side of the distribution pair housing is matched with the stopper on the left end cover through the left flange, and the right side of the distribution pair housing is matched with the stopper on the distribution piece through the inner flange of the distribution pair to ensure coaxiality, and at the same time, the distribution piece and the left end cover are provided with a left O-ring for installing the distribution piece and an O-ring for the left end cover to prevent oil leakage; the left flange and the distribution pair middle flange are matched with the left end cover and the distribution piece respectively through two left end cover locating pins, and the left end cover and the distribution piece, and are fixed with a inner hexagon screw and multiple sets of bolts, elastic gaskets and nuts.

[0007] Furthermore, the plunger sub-housing assembly includes: reinforcing ribs, a plunger sub-oil drain port pressure plate, a sensor outlet plate, a right flange, a cylinder O-ring, a plunger sub-housing, a right flange locating pin, a right O-ring of a distribution piece, and a plunger sub-center flange; the reinforcing ribs, the plunger sub-oil drain port pressure plate, the sensor outlet plate, the right flange and the plunger sub-center flange are welded to the plunger sub-housing by welding; two openings are respectively provided in the middle of the plunger sub-housing, and the two openings are respectively provided with a plunger sub-oil drain port pressure plate and a sensor outlet plate, the left side of the plunger sub-housing cooperates with the stop on the distribution piece through the left end plunger sub-center flange, and the right side of the plunger sub-housing cooperates with the stop on the cylinder body through the right flange, and a cylinder O-ring and a right O-ring of the distribution piece are respectively installed on the cylinder body and the distribution piece; the plunger sub-center flange and the right flange cooperate with the cylinder body and the distribution piece respectively through two right flange locating pins, and are fixed with a hexagon socket screw and multiple sets of bolts, elastic gaskets and nuts.

[0008] Furthermore, the external oil source system includes: a stop valve, an overflow loading system, a low-pressure oil source and a cooling system; wherein the overflow loading system includes a proportional overflow valve and a safety valve arranged in parallel, the low-pressure oil source includes an oil tank, the oil tank pipeline is connected to a low-pressure pump with a motor a, the outlet pipeline of the low-pressure pump is connected to an essential oil filter and an overflow valve, the cooling system includes a gear pump with a motor b and an oil tank cooling device, the motor a drives the low-pressure pump, through the overflow valve, to load low-pressure oil, the oil passes through the essential oil filter and the distribution pair test part in turn; the distribution pair test part loads high-pressure oil through the proportional overflow valve in the overflow loading system, and introduces it into the plunger pair test part, and a stop valve is arranged in the middle of the pipeline; when the oil temperature is too high, the motor b starts, driving the gear pump to introduce the oil into the oil tank cooling device.

[0009] Furthermore, the front and rear end faces of the distribution component are respectively provided with an oil inlet and an oil outlet, the oil inlet is connected to an external oil source system, the oil inlet is connected to the distribution pair test part through the internal oil channel of the distribution component, the oil outlet is connected to the oil port pipelines of the two cylinder plunger chambers in the cylinder body, and a stop valve is provided in the middle of the pipeline, thereby introducing the high-pressure oil loaded in the distribution pair test part into the plunger pair test part through the hydraulic pipeline.

[0010] Further, the cylinder body includes a plunger hole and a spring hole; the spring hole is a cylindrical hole opened at the center of the cylinder body, and the plunger hole part is two cylindrical holes surrounding the spring hole; in the cylinder body plunger cavity formed by one of the plunger holes, there are 2 groups of 4 eddy current displacement sensors located behind the cylinder body bushing, each group of eddy current displacement sensors is located on the same cross section of the plunger hole and is arranged at an angle of 90°. According to the principle that two measuring points and a radius determine a circle, and two circles determine a cylindrical position, the displacement of the measuring point obtained by the 4 eddy current displacement sensors is The parameters are used to determine the spatial position of the long plunger body in the plunger cavity, and then the plunger auxiliary oil film thickness field, that is, the relative displacement between the cylinder liner and the long plunger body, is calculated; in order to avoid damaging the oil film integrity area at the contact between the cylinder liner and the long plunger body, the installation position of the eddy current displacement sensor is set behind the cylinder liner in the plunger hole; because the four eddy current displacement sensors need to sense the plunger body at all times, the cylinder plunger cavity and the long plunger body are lengthened to ensure that the stroke of the long plunger body is always within the detection range of the four eddy current displacement sensors.

[0011] Furthermore, the cylinder body and the right flange in the plunger auxiliary housing part are fixed by multiple sets of bolts, elastic washers and nuts; and multiple inclined sheets are placed at different angles and positions between the cylinder body and the right flange to simulate different inclined states of the cylinder body.

[0012] A method for testing the oil film of the flow pair and the plunger pair of a high-pressure and large-displacement axial piston pump, the steps are as follows: The motor drives the spindle to rotate. The spindle is supported by sliding bearings, tapered roller bearings, swash plate seats, and cylindrical roller bearings. The rotation speed of the spindle is detected by a speed sensor equipped on the motor. In the distribution pair test part, the main shaft drives the rotor to rotate through the middle spline, and then drives the distribution pair sliding shoe and plunger body connected by the ball joint pair to rotate. The plunger body is installed in the rotor bushing nested in the rotor plunger cavity. The plunger body and the distribution pair sliding shoe assembly are pressed against the distribution pair inclined plate by the disc spring force under the joint action of the pressure plate, the distribution pair ball joint, the disc spring and the adjustment gasket, and cooperate with the inclined surface of the multi-angle distribution pair inclined plate to form rotation around the main shaft and reciprocating motion along the axial direction; the oil distribution plate is fixed in the distribution piece to realize the isolation of the high and low pressure oil areas and complete the oil distribution; the reciprocating motion of the plunger body causes the periodic change of the rotor plunger cavity volume. When the rotor plunger cavity volume increases, the low-pressure oil is sucked from the external oil source system through the oil inlet of the distribution piece to complete the oil suction function; when the rotor plunger cavity volume decreases, the high-pressure oil is loaded from the overflow loading system in the external oil source system through the oil outlet of the distribution piece to complete the oil discharge function; The sensor measuring plate is installed on the rotor through three countersunk screws. The eddy current displacement sensor collects the oil film thickness at the distribution pair by expanding the area of ​​the rotor bottom surface; the outer ring diameter of the original oil distribution plate is expanded by 30%, and three eddy current displacement sensors are evenly installed around the outer ring facing the sensor measuring plate. The sensor line is led out through the sensor line outlet hole opened in advance on the distribution piece, and is isolated from the tapered roller bearing through the sensor line protection plate; One end of a rotor washer acts on the main shaft spline and the other end acts on the distribution pair spring. Another rotor washer acts on the distribution pair spring and the other end acts on the elastic retaining ring for the hole, and then acts on the rotor, so that the rotor and the oil distributor are fitted together before the test begins; the distribution pair test device is placed in the distribution pair housing assembly that has been welded to seal it in the oil; In the plunger pair test device, the main shaft drives the swash plate seat to rotate, and then drives the plunger pair swash plate designed for dynamic balancing to rotate, and two plunger pair shoes and long plunger bodies act on the upper and lower symmetrical positions of the plunger pair swash plate inclined surface; the plunger pair shoe is connected to the long plunger body through a ball joint pair, and the long plunger body is installed in the cylinder bushing of the cylinder plunger hole, so that one of the long plunger bodies and the cylinder bushing constitute the plunger pair to be tested; the long plunger body and the plunger pair shoe assembly are pressed on the plunger pair swash plate by the joint action of the symmetrical pressure plate, the plunger pair ball joint, the plunger pair spring and the spring gasket, and the high-pressure oil introduced into the plunger cavity from the distribution pair test part, and make a linear reciprocating motion with the rotation of the swash plate, wherein the plunger pair spring is changed by adding spring gaskets of different thicknesses. The size of the spring force changes the clamping force acting on the plunger auxiliary sliding shoe; by placing multiple inclined thin sheets at different angles and positions between the cylinder body and the right flange, the tilt state of the cylinder body can be simulated; on a plunger cavity of the cylinder body, two sets of sensor mounting holes with an angle of 90° are set on the cylinder body, so that two pairs of eddy current displacement sensors are set to detect the posture change of the long plunger body when it moves in the plunger cavity of the cylinder body. The posture change is the oil film thickness. At the same time, in order to avoid damaging the integrity of the plunger auxiliary oil film and avoid the area where the cylinder bushing is located, the eddy current displacement sensor is required to always be able to detect the long plunger body, so the plunger cavity and the long plunger body are lengthened; the eddy current displacement sensor line is led out through the sensor outlet plate welded on the plunger auxiliary housing; The operation of the external oil source system relies on the overflow valve to supply low-pressure oil, which is introduced into the distribution sub-test part through the oil inlet provided on the distribution part and its internal oil channel. The distribution sub-test part discharges oil through the oil outlet of the distribution part, and relies on the proportional overflow valve in the overflow loading system to load high-pressure oil, which is again introduced into the bottom of the long plunger body in the cylinder through the hydraulic pipeline and fed into the cylinder plunger cavity, so as to supply high-pressure oil to the bottom of the long plunger body of the plunger sub-test part; the test state of the plunger sub-test part is realized by opening and closing the stop valve; the oil in the shell is led out through the distribution sub-oil drain port pressure plate welded on the distribution sub-shell and the plunger sub-oil drain port pressure plate welded on the plunger sub-shell, and the cooling system is manually opened through the temperature signal on the industrial computer to cool the oil of the entire experimental device.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This device has two parts: the flow distribution pair test and the plunger pair test. In the flow distribution pair test part, on the basis of completely retaining the core parts of the prototype pump, only the rotor and the oil distribution plate are adapted for sensor installation, so as to restore the oil film morphology and lubrication characteristics of the flow distribution pair under real working conditions to the maximum extent, and make appropriate improvements to the variable inclination angle swash plate, rear cover and housing with small influence on the motion state of the flow distribution pair and complex structure, so as to improve the test accuracy of the oil film thickness of the flow distribution pair. In the plunger pair test device, the overall design concept of swash plate drive-cylinder body fixed is adopted, and the sensor is arranged on the cylinder body, which equivalently restores the axial reciprocating motion of the long plunger body that plays a leading role in the oil film characteristics of the plunger pair, and weakens the influence of the revolution and spin of the long plunger body. The double plungers are arranged symmetrically at an angle of 180° to each other. The upper side is the plunger to be tested, and the lower side is the balancing plunger. The load torque of the balancing plunger auxiliary swash plate, the axial force and overturning torque of the long plunger acting on the swash plate are borne by the tapered roller bearing. At the same time, in order to avoid damaging the integrity of the plunger auxiliary oil film and avoid the area where the copper cylinder bushing is located, the long plunger body is lengthened. By adding multiple inclined thin slices at different positions and angles between the cylinder body and the right flange, the tilting state of the cylinder body can be simulated, making the test of the plunger auxiliary more in line with the actual working conditions. The two test devices are connected together through the distribution piece and the main shaft, which not only allows the two friction pairs to be tested synchronously or in time, but also enables the distribution pair test device to supply high-pressure oil for the plunger auxiliary test. Therefore, the test bench does not need a high-pressure oil source, which effectively realizes cost control. The displacement adjustment of the two test devices is achieved by replacing swash plates with different inclination angles. The swash plates are fixed by symmetrical positioning pins, and the displacement test of multiple swash plate inclination angles can be completed. The overall structure of the device is simple and reliable, the parts are easy to replace, and the processing and testing costs are low. The invention is produced with the in-depth development of industrial technology, and people have put forward higher pressure levels, higher displacements, and higher efficiency performance requirements for axial piston pumps. The successful development of the high-pressure and large-displacement friction pair oil film characteristic test bench will surely provide strong support for the research of high-load friction pair mixed lubrication model, friction pair wear degradation mechanism, friction pair surface modification anti-friction and anti-wear effect evaluation, etc.

[0014] This device is designed to meet the urgent need for axial piston pumps to develop towards higher pressure and larger displacement performance. It can simulate the actual working conditions of the prototype pump, measure the oil film at the distribution pair and the plunger pair, measure the operating speed and the oil pressure in the plunger chamber, and its accessories are easy to replace, which can support the research work on the distribution pair and plunger pair structures with different performances. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the principle of the oil film characteristic test device of the friction pair of the high-pressure axial piston pump of the present invention; Figure 2 A schematic diagram of the structure of the main shaft in an embodiment of the present invention; Figure 3This is a schematic diagram of the structure of the flow distribution component in an embodiment of the present invention; Figure 4 A schematic diagram of the hydraulic principle of a testing device in an embodiment of the present invention; Figure 5 Schematic diagram of the cylinder micro-motion structure in an embodiment of the present invention; Figure 6 It is a structural perspective view of a cylinder body in an embodiment of the present invention.

[0016] In the figure: motor 1, coupling 2, flat key 3, main shaft 4, shaft end pressure plate 5, pressure plate screw 6, left end cover 7, left flange 8, reinforcing rib 9, distribution auxiliary swash plate 10, pressure plate 11, distribution auxiliary sliding shoe 12, distribution auxiliary oil drain port pressure plate 13, plunger body 14, rotor bushing 15, rotor 16, sensor measuring plate 17, oil distribution plate 18, positioning pin 19, bearing seat 20, sliding bearing 21, sensor line protection sheet 22, distribution piece 23, tapered roller bearing 24, hexagon socket screw 25, swash plate seat 26, plunger auxiliary swash plate 27, plunger auxiliary oil drain port pressure plate 28, sensor line outlet plate 29, right flange 30, cylinder body 31, long plunger body 32, spring washer 33, plunger auxiliary spring 34, plunger auxiliary ball joint 35, cylinder body O-ring 36, plunger auxiliary housing 37, Right flange cylindrical pin 38, cylinder bushing 39, symmetrical pressure plate 40, plunger pair sliding shoe 41, plunger pair swash plate cylindrical pin 42, distributor right O-ring 43, plunger pair middle flange 44, bolt 45, elastic washer 46, nut 47, distributor left O-ring 48, distributor pair middle flange 49, countersunk screw 50, hole elastic retaining ring 51, rotor washer 52, distributor pair spring 53, distributor pair housing 54, distributor pair ball joint 55, disc spring 56, adjustment gasket 57, left end cover cylindrical pin 58, left end cover O-ring 59, distributor pair swash plate cylindrical pin 60, shaft elastic retaining ring 61, cylindrical roller bearing 62, shaft end pressure plate O-ring 63, skeleton oil seal 64, inclined sheet 65, stop valve 66, overflow loading system 67, low pressure oil source 68, cooling system 69; Oil inlet 231, oil outlet 232, proportional relief valve 671, safety valve 672, motor a681, low-pressure pump 682, essential oil filter 683, relief valve 684, motor b691, gear pump 692. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0018] like Figure 1As shown, the present invention discloses a high-pressure axial piston pump friction pair oil film characteristic test device, comprising: a transmission part, a distribution pair housing assembly, a distribution pair test part, a plunger pair housing assembly, a plunger pair test part, an eddy current displacement sensor, a shaft end pressure plate 5, a pressure plate screw 6, a left end cover 7, a distribution piece 23, a distribution piece right O-ring 43, a distribution piece left O-ring 48, a left end cover O-ring 59, a shaft end pressure plate O-ring 63, a skeleton oil seal 64, and an external oil source system; wherein the transmission part drives the distribution pair test part and the plunger pair test part to operate in turn; the distribution pair test part and the plunger pair test part are respectively installed on the distribution pair housing assembly and the plunger The auxiliary housing assembly is inside so that the test unit is immersed in oil; the distribution pair test unit and the plunger pair test unit rely on the distribution piece 23 to realize the connection between the structure and the oil circuit; the left end cover O-ring 59 is placed on the left end cover 7 to prevent radial oil leakage; the right O-ring 43 of the distribution piece and the left O-ring 48 of the distribution piece are placed on both sides of the distribution piece to prevent radial oil leakage; the shaft end pressure plate 5 is installed on the left end cover 7 using multiple sets of pressure plate screws 6; the shaft end pressure plate O-ring 63 and the skeleton oil seal 64 are placed on the shaft end pressure plate 5 to prevent axial oil leakage and the intrusion of external environment dust, etc.; the external oil source system is used to supply low-pressure oil, loading and cooling oil to the test device.

[0019] The transmission part includes: a motor 1, a coupling 2, a flat key 3, a main shaft 4, a bearing seat 20, a sliding bearing 21, a tapered roller bearing 24, a swash plate seat 26, a plunger auxiliary swash plate 27, a plunger auxiliary swash plate cylindrical pin 42, a shaft elastic retaining ring 61, and a cylindrical roller bearing 62; the motor 1 is fixed on the ground, and the motor 1 is connected to the coupling 2 through a key, such as Figure 2 As shown, a flat key 3 is provided on the left end of the main shaft 4, a spline connected to the sliding bearing 21 is provided in the middle part, and a spline connected to the swash plate seat 26 is provided at the right end tail; the main shaft 4 is connected to the coupling through the flat key 3, and the motor 1 transmits power to the main shaft 4 through the coupling 2; the main shaft 4 is penetrated by the tapered roller bearing 24, the sliding bearing 21, the swash plate seat 26, and the cylindrical roller bearing 62, and the cylindrical roller bearing 62 is fixed to the main shaft 4 through the shaft elastic retaining ring 61 and the shoulder of the main shaft 4. At the same time, the tapered roller bearing 24 is installed between the swash plate seat 26 and the distributor 23 by the shaft end pressure plate 5 fixed on the left end cover 7 by the pressure plate screw 6; the sliding bearing 21 is installed in the bearing seat 20, and the bearing seat 20 is installed in the distributor 23; the plunger auxiliary swash plate 27 is installed on the swash plate seat 26 through two plunger auxiliary swash plate cylindrical pins 42, and the plunger auxiliary swash plate is designed for dynamic balancing.

[0020] The flow distribution pair housing assembly includes: a left flange 8, a reinforcing rib 9, a flow distribution pair oil drain port pressure plate 13, a hexagon socket screw 25, a bolt 45, an elastic gasket 46, a nut 47, a left O-ring 48 of the flow distribution piece, a flow distribution pair middle flange 49, a flow distribution pair housing 54, a left end cover positioning pin 58, and a left end cover O-ring 59; the left flange 8, the reinforcing rib 9, the flow distribution pair oil drain port pressure plate 13 and the flow distribution pair middle flange 49 are all welded to the flow distribution pair housing 54 by welding; the flow distribution pair The two ends of the housing 54 are respectively matched with the stoppers of the left end cover 7 and the distributor 23, and the left O-ring 48 of the distributor and the left end cover O-ring 59 are installed at the same time, which not only ensures the concentricity requirements of the test device, but also ensures the sealing requirements of the test device; the left flange 8 and the flange 49 of the distributor are respectively matched with the left end cover 7 and the distributor 23 through two left end cover positioning pins 58, and play a positioning role, and are fixed with a hexagon socket screw 25 and multiple sets of bolts 45, elastic washers 46, and nuts 47; The distribution pair test part includes: a distribution pair swash plate 10, a pressure plate 11, a distribution pair sliding shoe 12, a plunger body 14, a rotor bushing 15, a rotor 16, a sensor measuring plate 17, an oil distribution plate 18, a positioning pin 19, a countersunk screw 50, an elastic retaining ring for a hole 51, a rotor washer 52, a distribution pair spring 53, a distribution pair ball joint 55, a disc spring 56, an adjustment gasket 57, and a distribution pair swash plate cylindrical pin 60; the distribution pair swash plate 10 is installed on the left end cover 7 through two distribution pair swash plate cylindrical pins 60; 9 plunger bodies 14 are installed in 9 rotor bushings 15 nested in the holes of the rotor 16, the ball head end of the plunger body 14 is hinged with the distribution pair sliding shoe 12, and the plunger body 14 and the distribution pair sliding shoe 12 assembly are pressed on the distribution pair swash plate by the pressure plate 11, the distribution pair ball joint 55, the disc spring 56 and the adjustment gasket 57. On the disk 10, the rotor 16 is connected to the main shaft 4 through the spline. When the main shaft 4 rotates under the drive of the motor 1, the rotating rotor 16 drives the distribution pair sliding shoe 12 and the plunger body 14 assembly to rotate, and under their joint action, they make reciprocating motion in the rotor bushing 15 to complete the oil suction and discharge work; the sensor measuring plate 17 is installed on the rotor 16 through three countersunk screws 50; the outer ring of the oil distribution plate 18 is evenly installed with three eddy current displacement sensor probes facing the sensor measuring plate 17, and is fixed to the distribution piece 23 through the positioning pin 19; one end of a rotor washer 52 acts on the spline of the main shaft 4, and the other end acts on the distribution pair spring 53, and the other end of the rotor washer 52 acts on the distribution pair spring 53, and the other end acts on the elastic retaining ring 51 for the hole, and then acts on the rotor 16, so that the rotor 16 and the oil distribution plate 18 fit together.

[0021] The plunger auxiliary housing assembly includes: a reinforcing rib 9, a plunger auxiliary oil drain port pressure plate 28, a sensor outlet plate 29, a right flange 30, a cylinder O-ring 36, a plunger auxiliary housing 37, a right flange positioning pin 38, a right O-ring 43 of a distribution piece, and a plunger auxiliary middle flange 44; the reinforcing rib 9, the plunger auxiliary oil drain port pressure plate 28, the sensor outlet plate 29, the right flange 30 and the plunger auxiliary middle flange 44 are all welded to the plunger auxiliary housing 37 by welding; the plunger auxiliary housing 37 The two ends are respectively matched with the stoppers of the cylinder body 31 and the distribution piece 23, and are respectively installed with the cylinder body O-ring 36 and the distribution piece right O-ring 43, which not only ensures the concentricity requirements of the test device, but also ensures the sealing requirements of the test device; the piston sub-flange 44 and the right flange 30 are respectively matched with the cylinder body 31 and the distribution piece 23 through two right flange locating pins 38 to play a positioning role, and are fixed with a hexagon socket screw 25 and multiple sets of bolts 45, elastic gaskets 46 and nuts 47.

[0022] The plunger auxiliary test part includes: a cylinder body 31, a long plunger body 32, a spring washer 33, a plunger auxiliary spring 34, a plunger auxiliary ball joint 35, a cylinder body O-ring 36, a cylinder body bushing 39, a symmetrical pressure plate 40 and a plunger auxiliary sliding shoe 41; wherein, the long plunger body 32 is installed in the cylinder body bushing 39 nested in the hole of the cylinder body 31, the ball head end of the long plunger body 32 is hinged to the plunger auxiliary sliding shoe 41, and the long plunger body 32 and the plunger auxiliary sliding shoe 41 assembly are jointly acted on by the symmetrical pressure plate 40, the plunger auxiliary ball joint 35, the plunger auxiliary spring 34 and the spring washer 33. Pressed on the piston auxiliary swash plate 27, when the main shaft 4 rotates under the drive of the motor 1, the swash plate seat 26 and the piston auxiliary swash plate 27 are driven to rotate, and the rotating piston auxiliary swash plate 27 partially pushes the piston auxiliary sliding shoe 41 and the long piston body 32 assembly, so that it reciprocates in the cylinder bushing 39, thereby simulating the dynamic behavior of the piston pair in the axial piston pump; the cylinder O-ring 36 is placed on the cylinder 31 to prevent axial leakage of oil; two pairs of eddy current displacement sensor probes are installed directly above a plunger cavity of the cylinder 31, which are 90 degrees to each other and have a certain axial distance.

[0023] The external oil source system includes: a stop valve 66, an overflow loading system 67, a low-pressure oil source 68 and a cooling system 69; wherein the overflow loading system 67 is composed of a proportional overflow valve 671 and a safety valve 672; the low-pressure oil source 68 is composed of a motor a681, a low-pressure pump 682, an essential oil filter 683 and an overflow valve 684; the cooling system 69 is composed of a motor b691, a gear pump 692 and a cooling device; the motor a681 drives the low-pressure pump 682 to load low-pressure oil through the overflow valve 684, and the oil passes through the essential oil filter 683 and the distribution pair test part in turn; the distribution pair test part loads high-pressure oil through the proportional overflow valve 671 in the overflow loading system 67, and introduces it into the plunger pair test part, and a stop valve 66 is set in the middle of the pipeline; when the oil temperature is too high, the motor b691 starts to drive the gear pump 692 to introduce the oil into the cooling device, such as Figure 4 shown.

[0024] like Figure 3 As shown, the front and rear end surfaces of the distribution member 23 are respectively provided with an oil inlet 231 and an oil outlet 232. The oil inlet 231 of the distribution member 23 is connected to the external oil source system and the distribution pair test part, and the oil outlet 232 is connected to two symmetrical oil ports at the tail end of the cylinder plunger cavity on the cylinder body 31; the external oil source is driven by the motor a681 to drive the low-pressure pump 682, and the low-pressure oil is supplied through the overflow valve 684, and is introduced into the distribution pair test part through the distribution member 23. The distribution pair test part relies on the proportional overflow valve 671 in the overflow loading system 67 to load the high-pressure oil, and the safety valve 672 plays a protective role. The high-pressure oil is introduced into the plunger pair test part through the distribution member 23 again, and the high-pressure oil is supplied for the plunger pair oil film test, thereby reducing a set of high-pressure oil source devices for the entire test device; the stop valve 66 in the external oil source system pipeline is opened and closed, and the different experimental states of the test device are quickly switched. When it is opened, the plunger pair test part is tested, and when it is closed, the test is stopped.

[0025] The cylinder body 31 is formed of a plunger hole portion and a spring hole portion in one piece, which simplifies the test device, and the intermediate body portion is designed to reduce weight; cylindrical holes are opened in the center and both vertical ends of the cylinder body 31, and the cylindrical hole in the center of the cylinder body 31 is installed with a preload support portion, and the two cylindrical holes around the center are used as cylinder plunger cavities to respectively install a cylinder bushing 39 and a long plunger body 32 to meet the simulation of different working conditions of the plunger auxiliary oil film test; the preload support portion includes a plunger auxiliary ball joint 35, a plunger auxiliary spring 34 and two spring washers 33, and in the plunger auxiliary low-pressure test link, the plunger auxiliary slide 41 and the long plunger body 32 assembly can be smoothly returned, and the spring washers 33 of different thicknesses can realize the adjustment of the preload acting on the plunger auxiliary slide 41. Figure 6As shown, four sensor openings for installing eddy current displacement sensors are provided on the side wall of the cylinder 31 at the cylinder plunger cavity. The four sensor openings are arranged in two groups front and back, and a 90-degree angle is formed between the two key sensor openings in each group, so that the installed eddy current displacement sensors form the same angle, thereby ensuring that the long plunger body 32 can always be detected when it moves in the cylinder liner 39. Since the long plunger body 32 will swing away from the central axis when moving in the cylinder liner 39, the detected swing information is thereby judged as the oil film thickness information here.

[0026] The cylinder body 31 and the right flange 30 in the housing part of the plunger pair are fixed by multiple sets of bolts 45, elastic washers 46 and nuts 47; multiple inclined thin sheets 65 are placed between the cylinder body 31 and the right flange 30, and the test data of the distribution pair test is used to understand the inclination state of the cylinder body 31, and the actual working state is reproduced by placing the inclined thin sheets 65 at different angles and positions, thereby reducing the test error, such as Figure 5 shown.

[0027] Multiple pressure sensors and temperature sensors in the external oil source system are connected to the data acquisition card, which is connected to the industrial computer. The industrial computer displays and processes the collected data. Through the temperature signal displayed in real time on the industrial computer, the cooling system 69 is manually turned on to cool the oil in the entire device, ensuring the simulation of the actual working conditions during the test.

[0028] The working process of the present invention is as follows: The motor 1 transmits power to the main shaft 4 through the coupling 2. The main shaft 4 supported by the sliding bearing 21, the tapered roller bearing 24, the swash plate seat 26 and the cylindrical roller bearing 62 rotates under the drive of the motor 1. The rotation speed is adjusted by the external frequency converter and detected by the speed sensor equipped on the motor 1. In the distribution pair test part, the main shaft 4 drives the rotor 16 to rotate through the spline, and then drives the 9 distribution pair sliding shoes 12 and the plunger body 14 to rotate to complete the oil suction and discharge work. The opposite side of the distribution pair sliding shoe 9 and the plunger body 14 is the multi-angle distribution pair swash plate 10 fixed by two distribution pair cylindrical pins 60. The distribution pair sliding shoe 12 is connected to the plunger body 14 through a ball joint pair, and the plunger body 14 is installed in the rotor bushing 1 embedded in the hole of the rotor 16. 5; the plunger body 14 and the distribution pair sliding shoe 12 assembly are pressed against the distribution pair swash plate 10 by the joint action of the pressure plate 11, the distribution pair ball joint 55, the disc spring 56 and the adjustment gasket 57, wherein the disc spring force can be changed by adding different numbers of adjustment gaskets 57, thereby changing the force acting on the distribution pair sliding shoe 12; the sensor measuring plate 17 is installed on the rotor 16 by three countersunk screws 50, and the area of ​​the bottom surface of the rotor 16 is enlarged to facilitate the signal collection of the eddy current displacement sensor; the outer ring diameter of the oil distribution plate 18 is enlarged, and three eddy current displacement sensor probes are evenly installed around the outer ring of the sensor measuring plate 17, and the sensor line is led out through the sensor line outlet hole opened in advance in the distribution piece 23, and the sensor line is connected to the sensor line outlet hole through the sensor The inductive line protection plate 22 isolates it from the tapered roller bearing 24 and is fixed to the distribution piece 23 by the locating pin 19; one end of a rotor washer 52 acts on the spline of the main shaft 4 and the other end acts on the distribution sub-spring 53; one end of the other rotor washer 52 acts on the distribution sub-spring 53 and the other end acts on the elastic retaining ring 51 for the hole, and then acts on the rotor 16, so that the rotor 16 and the oil distribution plate 18 fit together; the distribution sub-assembly test device is placed in the distribution sub-shell assembly that has been welded, so that the entire device is sealed in the oil; in the plunger sub-test part, the main shaft 4 drives the swash plate seat 26 to rotate, and then drives the multi-angle plunger sub-swash plate 27 with dynamic balancing design to rotate, at the upper and lower symmetrical positions of the plunger sub-swash plate 27 inclined surface There are two plunger auxiliary shoes 41 and long plunger bodies 32 on each of them; the plunger auxiliary shoes 41 are connected to the long plunger body 32 through a ball joint pair, and the long plunger body 32 is installed in the cylinder bushing 39 in the cylinder hole of the cylinder body 31, wherein one of the long plunger bodies 32 and the cylinder bushing 39 constitutes the plunger pair to be tested; the long plunger body 32 and the plunger auxiliary shoes 41 assembly are pressed on the plunger auxiliary inclined plate 27 by the joint action of the symmetrical pressure plate 40, the plunger auxiliary ball joint 35, the plunger auxiliary spring 34 and the spring gasket 33, wherein the size of the spring force can be changed by adding spring gaskets 33 of different thicknesses, thereby changing the force acting on the plunger auxiliary shoes 41; by placing a plurality of inclined sheets 65 between the cylinder body 31 and the right flange 30, the tilting state of the cylinder body can be simulated;Two pairs of eddy current displacement sensor probes are installed directly above a cylinder plunger cavity of the cylinder body 31, which are 90° apart and have a certain axial distance. The sensor line is led out through the sensor line outlet plate 29 welded on the plunger sub-shell; the operation of the external oil source system relies on the overflow valve 684 to supply low-pressure oil, which is introduced into the distribution sub-test part through the distribution piece 23. The distribution sub-test part relies on the proportional overflow valve 671 in the overflow loading system 67 to load high-pressure oil, and then supplies high-pressure oil to the plunger sub-test part through the distribution piece 23 again, wherein the stop valve 66 in the pump station is opened and closed to realize the experimental state of the plunger sub-test part; the oil in the shell is led out through the distribution sub-oil drain port pressure plate welded on the distribution sub-shell 54 and the plunger sub-oil drain port pressure plate 28 welded on the plunger sub-shell 37, and the cooling system 69 is manually opened through the temperature signal on the industrial computer to cool the oil of the entire experimental device. ;

Claims

1. A high-pressure axial piston pump friction pair oil film characteristics testing device, characterized in that: include: The motor (1) as a power source, an external oil source system, a data acquisition card and an industrial computer, the motor (1) is connected to a horizontally arranged main shaft (4) through a coupling (2), the upper side of the main shaft (4) is provided with a left end cover (7), a distribution sub-test part and a plunger sub-test part from left to right, a distribution part (23) is provided between the distribution sub-test part and the plunger sub-test part, a through hole for accommodating the main shaft (4) is provided at the center of the distribution part (23), a bearing seat (20) for mounting a sliding bearing (21) is provided on the left side of the through hole of the distribution part (23), and a slant plate seat (26) is connected to the right side of the through hole of the distribution part (23) through a tapered roller bearing (24); wherein a shaft end pressure plate (5) is provided between the main shaft (4) and the left end cover (7) ) is movably connected to a cylindrical roller bearing (62) pressed by the main shaft (4), the cylindrical roller bearing (62) is fixedly connected to the shaft shoulder of the main shaft (4) through an elastic retaining ring (61) for the shaft, and the left side of the left end cover (7) fixes the shaft end pressure plate (5) through a pressure plate screw (6); wherein a distribution pair housing assembly is provided on the outer side of the distribution pair test part, and a plunger pair housing assembly is provided on the outer side of the plunger pair test part, and the distribution pair test part is connected to the plunger pair test part as a whole through a distribution piece (23), and a plurality of eddy current displacement sensors are respectively provided on the oil distribution plate (18) and the cylinder body (31); the pressure sensor, the temperature sensor in the external oil source system and the eddy current displacement sensor in the test device are all connected to the data acquisition card, and the data acquisition card is connected to the industrial computer; The flow distribution pair test part comprises a flow distribution pair slant plate (10) sleeved on the main shaft (4) and a rotor (16). The rotor (16) is axially provided with a variable diameter through hole. The front half of the variable diameter through hole matches the main shaft (4) through a spline. The diameter of the rear half of the variable diameter through hole is increased. A flow distribution pair spring (53) is provided between the inner wall of the through hole and the main shaft (4). A spherical surface is provided at the right end of the rotor (16). The rotor (16) fits with the spherical surface of the oil separation plate (18). The oil separation plate (18) is fixed to the flow distribution member (23) through a positioning pin (19). The oil separation plate (18) is fixed. The rotor (16) rotates under the drive of the main shaft (4). The oil separation plate (18) and the rotor (16) are connected. The rotor (16) and the oil separator (18) are lubricated by oil. Three evenly distributed eddy current displacement sensors are installed on the outer edge of the oil separator (18). A sensor measuring plate (17) for receiving eddy current signals is fixed to the right end of the rotor (16) by three countersunk screws (50). The relative displacement between the rotor (16) and the oil separator (18) is detected by the three eddy current displacement sensors, so that the thickness information of the oil film of the distribution auxiliary can be determined according to the displacement of the rotor (16) relative to the oil separator (18). The distribution auxiliary inclined plate (10) is fixed to the right side of the left end cover (7) by two upper and lower distribution auxiliary inclined plate cylindrical pins (60). The rotor (16) is provided with 9 plungers around the main shaft (4). The rotor bushing (15) is embedded in a cavity, each rotor bushing (15) is provided with a plunger body (14), the plunger body (14) is hinged with a distribution pair slide shoe (12) through a ball head end to form a combination, the plunger body (14) and the distribution pair slide shoe (12) are sequentially pressed against the right inclined surface of the distribution pair swash plate (10) by the disc spring (56) under the joint action of the pressure plate (11), the distribution pair ball joint (55), the disc spring (56) and the adjustment gasket (57); two rotor washers (52) are sleeved on the main shaft in the rear half of the variable diameter through hole of the rotor (16), the two rotor washers (52) are respectively arranged at the two ends of the distribution pair spring (53), and a rotor A washer (52) is arranged between a spline end portion of a main shaft (4) and a distribution auxiliary spring (53), and another rotor washer (52) is arranged between the distribution auxiliary spring (53) and a bearing seat (20), wherein a hole elastic retaining ring (51) is also arranged between the rotor washer (52) and the bearing seat (16); the spring force of the distribution auxiliary spring (53) acts on the hole elastic retaining ring (51) fixed on the rotor (16), thereby causing the spring force to act on the rotor (16), so that the rotor (16) is pressed against the oil separation plate (18); during operation, the rotor (16) and the oil separation plate (18) are fitted together, so that the displacement between the two is equal to the thickness of the oil film to be detected; The plunger auxiliary test part includes a plunger auxiliary swash plate (27) matched with the swash plate seat (26) and a cylinder body (31). The main shaft (4) is connected to the axis of the swash plate seat (26) through an end spline and driven. The swash plate seat (26) and the plunger auxiliary swash plate (27) are fixed by two upper and lower plunger auxiliary swash plate cylindrical pins (43). The left side of the cylinder body (31) matches the inclined surface of the plunger auxiliary swash plate (27). A preload support part is provided at the center of the cylinder body (31). The preload support part includes a piston receiving portion. The spring hole of the auxiliary spring (34) is provided with a shoulder for fixing the auxiliary plunger spring (34), the left end of the auxiliary plunger spring (34) is provided with a auxiliary plunger ball joint (35) through a spring washer (33), and the right end of the auxiliary plunger spring (34) is fixed to the shoulder through the spring washer (33); the cylinder body (31) is provided with two symmetrically arranged cylinder body plunger chambers around the central spring hole, and the tails of the two cylinder body plunger chambers are respectively provided with two oil ports connected to the external oil source system pipeline, and the cylinder body plunger chambers are connected to the external oil source system pipeline. A long plunger body (32) is provided through the cylinder bushing (39), the left end of the long plunger body (32) is a ball head end, and the long plunger body (32) is hinged with a plunger auxiliary sliding shoe (41) through the ball head end to form an assembly. The assembly consisting of the long plunger body (32) and the plunger auxiliary sliding shoe (41) is changed by adjusting the spring gasket (33) of different thicknesses under the joint action of the symmetrical pressure plate (40), the plunger auxiliary ball joint (35), the plunger auxiliary spring (34) and the spring gasket (33). The compression amount of the auxiliary spring (34) is pressed against the inclined surface of the auxiliary plunger swash plate (27) by the spring force of the auxiliary plunger spring (34); two pairs of eddy current displacement sensors are arranged on the side wall of a cylinder plunger cavity of the cylinder body (31) at an angle of 90 degrees to each other and axially spaced apart, and the two pairs of eddy current displacement sensors are used to detect the change in the position of the long plunger body (32) in the cylinder plunger cavity of the cylinder body (31), and the oil film thickness of the plunger pair is determined by the detected position of the long plunger body (32) in the cylinder plunger cavity.

2. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1 is characterized in that: The motor (1) is fixed on the ground. The motor (1) transmits power to the main shaft (4) through the coupling (2) and the flat key (3). The main shaft (4) transmits power to the rotor (16) and the swash plate seat (26) in sequence through the spline.

3. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1 is characterized in that: The flow distribution pair housing assembly comprises: a left flange (8), a reinforcing rib (9), a flow distribution pair oil drain port pressure plate (13), a hexagon socket screw (25), a bolt (45), an elastic gasket (46), a nut (47), a flow distribution piece left O-ring (48), a flow distribution pair middle flange (49), a flow distribution pair housing (54), a left end cover positioning pin (58), and a left end cover O-ring (59); the left flange (8), the reinforcing rib (9), the flow distribution pair oil drain port pressure plate (13) and the flow distribution pair middle flange (49) are all welded to the flow distribution pair housing (54) by welding; a flow distribution pair oil drain port pressure plate (13) is provided in the middle of the flow distribution pair housing (54); the flow distribution pair housing (54) is provided with a left O-ring (48), and the left end cover O-ring (59) is provided with a left O-ring (59). The left side of the (54) is matched with the stopper on the left end cover (7) through the left flange, and the right side of the distribution pair housing (54) is matched with the stopper on the distribution piece (23) through the distribution pair middle flange (49) to ensure coaxiality. At the same time, the distribution piece and the left end cover are provided with a left O-ring (48) for installing the distribution piece and an O-ring (59) on the left end cover to prevent oil leakage; the left flange (8) and the distribution pair middle flange (49) are matched with the left end cover (7) and the distribution piece (23) through two left end cover locating pins (58) respectively, and are fixed with a hexagon socket screw (25) and multiple sets of bolts (45), elastic washers (46), and nuts (47).

4. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1, characterized in that: The plunger sub-housing assembly comprises: a reinforcing rib (9), a plunger sub-oil drain port pressure plate (28), a sensor outlet plate (29), a right flange (30), a cylinder body O-ring (36), a plunger sub-housing (37), a right flange positioning pin (38), a distributor right O-ring (43), and a plunger sub-middle flange (44); the reinforcing rib (9), the plunger sub-oil drain port pressure plate (28), the sensor outlet plate (29), the right flange (30), and the plunger sub-middle flange (44) are all welded to the plunger sub-housing (37) by welding; the plunger sub-housing (37) is provided with two openings in the middle, and the plunger sub-oil drain port pressure plate (28) and the sensor outlet plate (29) are provided on the two openings, respectively. The outlet plate (29) is provided. The left side of the plunger sub-housing (37) is matched with the stopper on the distribution piece (23) through the left end plunger sub-middle flange (44). The right side of the plunger sub-housing (37) is matched with the stopper on the cylinder body (31) through the right flange (30). A cylinder body O-ring (36) and a distribution piece right O-ring (43) are respectively installed on the cylinder body (31) and the distribution piece (23). The plunger sub-middle flange (44) and the right flange (30) are respectively matched with the cylinder body (31) and the distribution piece (23) through two right flange locating pins (38), and are fixed by using a hexagon socket screw (25) and a plurality of bolts (45), elastic washers (46) and nuts (47).

5. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1, characterized in that: The external oil source system comprises: a stop valve (66), an overflow loading system (67), a low-pressure oil source (68) and a cooling system (69); wherein the overflow loading system (67) comprises a proportional overflow valve (671) and a safety valve (672) arranged in parallel, the low-pressure oil source (68) comprises an oil tank, the oil tank pipeline is connected to a low-pressure pump (682) with a motor a (681), the outlet pipeline of the low-pressure pump (682) is connected to an essential oil filter (683) and an overflow valve (684), and the cooling system (69) comprises a gear pump with a motor b (691). (692) and the oil tank cooling device, the motor a (681) drives the low-pressure pump (682) to load the low-pressure oil through the overflow valve (684), and the oil passes through the fine oil filter (683) and the distribution pair test part in sequence; the distribution pair test part loads the high-pressure oil through the proportional overflow valve (671) in the overflow loading system (67) and introduces it into the plunger pair test part, and a stop valve (66) is arranged in the middle of the pipeline; when the oil temperature is too high, the motor b (691) starts and drives the gear pump (692) to introduce the oil into the oil tank cooling device.

6. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1, characterized in that: The front and rear end surfaces of the flow distribution component (23) are respectively provided with an oil inlet (231) and an oil outlet (232); the oil inlet (231) is connected to an external oil source system; the oil inlet (231) is connected to the flow distribution pair test part through an internal oil passage of the flow distribution component (23); the oil outlet (232) is connected to the oil port pipelines of the two cylinder plunger chambers in the cylinder body (31); a stop valve (66) is provided in the middle of the pipeline, thereby introducing high-pressure oil loaded in the flow distribution pair test part into the plunger pair test part through the hydraulic pipeline.

7. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1, characterized in that: The cylinder body (31) comprises a plunger hole and a spring hole; the spring hole is a cylindrical hole opened at the center of the cylinder body (31), and the plunger hole part is two cylindrical holes surrounding the spring hole; in a cylinder plunger cavity formed by one of the plunger holes, two groups of four eddy current displacement sensors are arranged behind the cylinder bushing (39), each group of eddy current displacement sensors is located on the same cross section of the plunger hole and is arranged at an angle of 90 degrees, and according to the principle that two measuring points and a radius determine a circle, and two circles determine a cylindrical position, the displacement parameters of the measuring points obtained by the four eddy current displacement sensors are used to determine the position of the long plunger body (32) The spatial position in the plunger cavity is used to infer the plunger auxiliary oil film thickness field, that is, the relative displacement between the cylinder bushing (39) and the long plunger body (32); in order to avoid damaging the oil film integrity area at the contact point between the cylinder bushing (39) and the long plunger body (32), the installation position of the eddy current displacement sensor is set behind the cylinder bushing (39) in the plunger hole. Because the four eddy current displacement sensors need to sense the plunger body at all times, the cylinder plunger cavity and the long plunger body (32) are lengthened to ensure that the stroke of the long plunger body (32) is always within the detection range of the four eddy current displacement sensors.

8. The high-pressure axial piston pump friction pair oil film characteristic testing device according to claim 1, characterized in that: The cylinder body (31) and the right flange (30) in the plunger auxiliary housing portion are fixed by means of multiple sets of bolts (45), elastic washers (46) and nuts (47); and multiple inclined sheets (65) are placed at different angles and positions between the cylinder body (31) and the right flange (30) to simulate different inclined states of the cylinder body.

9. A method for testing the oil film of the flow pair and the piston pair of a high-pressure and large-displacement axial piston pump, characterized in that: Here are the steps: The motor (1) drives the main shaft (4) to rotate. The main shaft (4) is supported by a sliding bearing (21), a tapered roller bearing (24), a swash plate seat (26), and a cylindrical roller bearing (62). The rotation speed of the main shaft (4) is detected by a rotation speed sensor provided on the motor (1). In the flow distribution pair test part, the main shaft (4) drives the rotor (16) to rotate through the middle spline, thereby driving (9) flow distribution pair sliding shoes (12) and plunger bodies (14) connected by ball joints to rotate. The plunger body (14) is installed in a rotor bushing (15) nested in the rotor plunger cavity. The plunger body (14) and the flow distribution pair sliding shoe (12) assembly are pressed against the flow distribution pair inclined plate (10) by the disc spring (53) under the joint action of the pressure plate (11), the flow distribution pair ball joint (55), the disc spring (56) and the adjustment gasket (57), and cooperate with the inclined surface of the multi-angle flow distribution pair inclined plate (10) to form a rotation angle around the main shaft (4). ) rotation and axial reciprocating motion; the oil distribution plate (18) is fixed in the distribution piece (23) to achieve isolation of high and low pressure oil areas, thereby completing oil distribution; the reciprocating motion of the plunger body (14) causes a periodic change in the volume of the plunger cavity of the rotor (16); when the volume of the plunger cavity of the rotor (16) increases, low pressure oil is sucked from an external oil source system through an oil inlet (231) of the distribution piece (23), thereby completing an oil suction function; when the volume of the plunger cavity of the rotor (16) decreases, high pressure oil is loaded from an overflow loading system (67) in the external oil source system through an oil outlet (232) of the distribution piece (23), thereby completing an oil discharge function; The sensor measuring plate (17) is mounted on the rotor (16) by three countersunk screws (50), and the eddy current displacement sensor collects the oil film thickness at the distribution pair by expanding the area of ​​the bottom surface of the rotor (16); the outer ring diameter of the original oil distribution plate (18) is enlarged by 30%, and three eddy current displacement sensors are evenly installed around the outer ring of the sensor measuring plate (17); the sensor wire is led out through the sensor wire outlet hole pre-opened in the distribution piece (23), and is isolated from the tapered roller bearing (24) by the sensor wire protection thin plate (22); One end of a rotor washer (52) acts on the spline of the main shaft (4) and the other end acts on the distribution pair spring (53); one end of another rotor washer (52) acts on the distribution pair spring (53) and the other end acts on the hole elastic retaining ring (51), and then acts on the rotor (16), so that the rotor (16) and the oil distribution plate (18) are fitted together before the test begins; the distribution pair test device is placed in the distribution pair housing assembly that has been welded to seal it in oil; In the plunger auxiliary test device, the main shaft (4) drives the swash plate seat (26) to rotate, thereby driving the plunger auxiliary swash plate (27) with a dynamic balancing design to rotate, and two plunger auxiliary sliding shoes (41) and a long plunger body (32) act on the two symmetrical positions of the upper and lower inclined surfaces of the plunger auxiliary swash plate (27); the plunger auxiliary sliding shoes (41) and the long plunger body (32) are connected through a ball joint pair, and the long plunger body (32) is installed in a cylinder bushing (39) of a cylinder plunger hole, so that one of the long plungers The plunger body (32) and the cylinder bushing (39) constitute the plunger pair to be tested; the long plunger body (32) and the plunger pair sliding shoe (41) assembly are pressed against the plunger pair swash plate (27) by the combined action of the symmetrical pressure plate (40), the plunger pair ball joint (35), the plunger pair spring (34) and the spring washer (33) and the high-pressure oil introduced into the plunger cavity from the distribution pair test part, and perform linear reciprocating motion with the rotation of the swash plate, wherein the spring washer of different thicknesses is added to The sheet (33) changes the size of the spring force of the plunger auxiliary spring (34), thereby changing the pressing force acting on the plunger auxiliary sliding shoe (41); by placing a plurality of inclined thin sheets (65) at different angles and positions between the cylinder body (31) and the right flange (30), the tilt state of the cylinder body (31) is simulated; on a plunger cavity of the cylinder body (31), two groups of sensor mounting holes with an included angle of 90° are set on the cylinder body (31), so that two pairs of eddy current displacement sensors are set to detect the posture change generated when the long plunger body (32) moves in the cylinder plunger cavity, and the posture change is the oil film thickness. At the same time, in order to avoid damaging the integrity of the plunger auxiliary oil film and avoid the area where the cylinder bushing (39) is located, and at the same time, the eddy current displacement sensor is required to always be able to detect the long plunger body (32), the plunger cavity and the long plunger body (32) are lengthened; the eddy current displacement sensor line is led out through the sensor outlet plate (29) welded on the plunger auxiliary housing; The external oil source system is operated by supplying low-pressure oil through the overflow valve (684), which is introduced into the distribution sub-test part through the oil inlet (231) provided on the distribution part (23) and its internal oil passage. The distribution sub-test part discharges the oil through the oil outlet (232) of the distribution part (23), and relies on the proportional overflow valve (671) in the overflow loading system (67) to load the high-pressure oil, which is introduced into the bottom of the long plunger body (32) in the cylinder body (31) through the hydraulic pipeline and fed into the cylinder body plunger. The cavity is used to supply high-pressure oil to the bottom of the long plunger body (32) of the plunger auxiliary test part; the test state of the plunger auxiliary test part is realized by opening and closing the stop valve (66); the oil in the shell is led out through the distribution auxiliary oil drain port pressure plate welded on the distribution auxiliary shell (54) and the plunger auxiliary oil drain port pressure plate (28) welded on the plunger auxiliary shell (37), and the cooling system (69) is manually opened through the temperature signal on the industrial control computer to cool the oil in the entire experimental device.

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