A 360-degree oil film morphology testing device for a plunger pair

Abstract

The present invention discloses a 360-degree oil film morphology testing device for a plunger pair, and relates to the field of hydraulic component testing. It includes a hydraulic drive motor, a torque meter, and a swash plate shaft assembly; it also includes an experimental box, and the swash plate shaft is installed at the opening on the left end of the box; a plunger bracket is installed at the bottom of the box, and a cylinder support seat is installed above it; a sealing cover is installed at the opening on the right end of the box, and a bearing seat is installed at the left end of the sealing cover; the cylinder support seat and the bearing seat are respectively equipped with bearings for supporting the cylinder body; a worm wheel is installed on the cylinder body, and the cylinder body can be driven to rotate 360 ​​degrees by driving the worm; the right side of the box is an oil supply pipeline. The present invention reduces the number of cylinder sensors installed, reduces costs, and realizes the circumferential arbitrary angle measurement of the plunger oil film characteristics.

Description

Technical Field

[0001] The invention relates to a 360-degree oil film morphology testing device for a plunger pair, belonging to the field of hydraulic component testing. Background Art

[0002] Hydraulic systems are widely used in the industrial field. They have made great contributions to the automation, intelligence and performance improvement of equipment in the fields of engineering machinery and equipment manufacturing. Hydraulic pumps play a vital role as the energy source of hydraulic systems. At present, axial piston pumps are widely used in various engineering practices due to their high pressure, high volumetric efficiency, and easy flow regulation. Therefore, it is of great significance to test the oil film characteristics of the piston pair under working conditions.

[0003] Traditional plunger pair oil film test systems mostly use fixed sensors to collect oil film characteristic parameters at fixed points. The test system needs to install multiple sensors. Such a design is costly, the oil film test range is limited, and the large number of sensors makes the installation and disassembly of the test system inconvenient. Therefore, in view of the shortcomings of the above test system, a plunger pair 360-degree oil film morphology test device is proposed. The plunger pair oil film characteristic parameters are obtained through experiments and the correctness of the theoretical research results is verified to provide support for the optimal design of the plunger pair of the plunger pump. Summary of the invention

[0004] In order to overcome the defects of traditional plunger pair oil film testing systems such as high design cost, limited testing range, and inconvenient installation and disassembly, the present invention provides a plunger pair 360-degree oil film morphology testing device, which can reduce the number of circumferential sensors installed on the plunger pump cylinder body and reduce costs, thereby enabling the cylinder body to rotate around its own axis and realize circumferential arbitrary angle testing of the internal plunger pair oil film characteristics, thereby solving the problem of limited oil film testing range.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a 360-degree oil film morphology test device for a plunger pair, a test system based on this principle, including a hydraulic drive motor, a torque meter, and a swash plate shaft assembly; it also includes an experimental box, the left end opening of the box is equipped with a swash plate shaft; a plunger bracket is installed at the bottom of the box, and a cylinder support seat is installed above it; a sealing cover is installed at the right end opening of the box, and a bearing seat is installed at the left end of the sealing cover; the cylinder support seat and the bearing seat are respectively equipped with bearings for supporting the cylinder body; the right side of the box is an oil supply pipeline;

[0006] The above-mentioned plunger pair 360-degree oil film morphology testing device, the experimental box body is a two-cavity shell structure, the larger cavity on the right is the experimental oil cavity, and the smaller cavity on the left is used to install the swash plate shaft assembly; the swash plate and the main shaft are an integrated structure, and a double-row angular contact ball bearing and a single-row angular contact ball bearing, two large and small bearing sleeves and a bearing end cover constitute the swash plate shaft assembly, which is sealed and connected to the box body by bolts; a step of the swash plate shaft is provided with a round nut installation groove, and the round nut and the retaining washer are used to realize the pre-tightening of the single-row angular contact ball bearing; a keyway is provided at the left end of the swash plate shaft, which is connected to the torque meter through a coupling; the torque meter is connected to the hydraulic motor through another coupling.

[0007] The above-mentioned plunger pair 360-degree oil film morphology testing device, in the experimental oil chamber, the plunger bracket is installed at the bottom by bolts, and the cylinder support seat and the plunger bracket are connected by bolts; there is a positioning shoulder in the middle of the cylinder body, and the left side of the shoulder is connected to the cylinder support seat through the first support bearing; the cylinder surface is processed with mounting holes for eddy current displacement sensor, armored thermocouple, and piezoelectric pressure sensor; a step hole is made inside the cylinder body, the left end is divided into a positioning hole for installing the bushing, and the right end is divided into an oil inlet pipe hole; a test bushing is installed at the left end of the cylinder body, and the positioning holes of the eddy current displacement sensor, armored thermocouple, and piezoelectric pressure sensor are processed on the surface of the bushing; three sensors are installed on the cylinder body, and the right end of the cylinder body is rotatably connected to the bearing seat through the second support bearing; an auxiliary plunger is installed on the left side of the plunger bracket, parallel to the upper test plunger; an oil inlet channel is opened inside the plunger bracket, which is connected to the oil supply pipeline branch under the box.

[0008] The above-mentioned 360-degree oil film morphology testing device for the plunger pair has an opening on the right side of the experimental oil chamber, which is sealed and connected to the sealing cover of the box body; the center of the left end of the sealing cover is a concave hole, and an oil guide pipe sleeve is installed in the middle. The oil guide pipe on the left side is fixed to the oil guide pipe sleeve through two semicircular oil guide pipe pressure plates, and the pressure plate and the oil guide pipe sleeve are fixed in the sealing cover hole by bolts; the left end of the oil guide pipe passes through the through hole of the bearing seat and enters the oil guide pipe hole of the cylinder body, and fits with the clearance at the right end of the cylinder body; a diverter block is installed on the right end of the sealing cover by bolts, and the right end of the diverter block is connected to the oil inlet pipe, and the lower part is connected to the oil supply branch pipe to form an oil supply pipeline; a pressure sensor is installed on the rear side of the diverter block.

[0009] To further optimize the design, a 360-degree oil film morphology testing device for a plunger pair is provided with a worm gear through a thin flat key on the right side of the middle shoulder of the cylinder body, and the worm gear cooperates with the upper worm; the worm is installed on the worm bracket through a pair of bearings, a blind cover and a transparent cover; the worm bracket is connected to the bottom of the experimental oil chamber through bolts; a through hole is opened at the rear of the oil chamber, and the shaft at one end of the worm passes through the transparent cover and extends out of the box body, and is connected to the stepper motor through a coupling; the stepper motor is fixed to the motor bracket by bolts, and the motor bracket is fixed to the outer wall of the box body by bolts.

[0010] The invention has the beneficial effect that the technical solution drives the swash plate shaft to rotate and drives the plunger to reciprocate through the hydraulic motor. During the test, the test plunger and the auxiliary plunger are provided with pressure oil by the same hydraulic oil source through the oil supply pipeline. The bottom of the sliding shoe and the swash plate form an oil hydrostatic support, which can balance the force and simulate the working condition of the real pump. The cylinder body is fixed by two angular contact ball bearings, which can prevent the cylinder body from being driven by the plunger to produce axial movement and can also perform circumferential rotation around the axis. The self-locking of the worm gear and the self-locking of the stepper motor are used to prevent the cylinder body from producing circumferential rotation during a test; the stepper motor is used to drive the worm and then drive the worm gear and the cylinder body to rotate 360° around their own axis, so as to perform tests at any angle, obtain the oil film characteristics at any angle in the plunger cavity when the plunger moves, and realize the measurement of the 360-degree plunger surface oil film characteristics with a small number of sensors, effectively solving the problems of high design cost, inconvenient installation and disassembly, and limited oil film test range in the traditional plunger auxiliary oil film test system. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a cross-sectional view of the experimental box of the present invention without a top cover;

[0012] Figure 2 A top view of the test system of the present invention without a box top cover;

[0013] Figure 3 It is an isometric view of the cylinder of the present invention;

[0014] Figure 4 It is an isometric view of the bushing of the present invention.

[0015] In the figure, 1. swash plate shaft, 2. lip seal ring, 3. round nut, 4. retaining washer, 5. bearing end cover, 6. large bearing sleeve, 7. single row angular contact ball bearing, 8. bearing sleeve seal ring, 9. small bearing sleeve, 10. double row angular contact ball bearing, 11. experimental oil chamber, 12. test plunger sliding shoe, 13. test plunger, 14. bushing, 15. cylinder body, 16. cylinder body support seat, 17. first cylinder body support bearing, 18. worm gear, 19. worm, 2 0. First worm support bearing, 21. Stepper motor, 22. Stepper motor coupling, 23. Stepper motor bracket, 24. Bearing cover, 25. Sleeve, 26. Second bearing side seal ring, 27. Second bearing outer ring seal ring, 28. Second cylinder support bearing, 29. Bearing seat, 30. Bearing seat seal ring, 31. Sealing cover, 32. Oil pipe pressure plate, 33. Oil pipe sleeve, 34. Oil pipe, 35. Diverter block, 36. Pressure sensor , 37. Oil inlet pipe, 38. Oil guide pipe sleeve sealing ring, 39. Oil supply branch pipe, 40. Experimental box, 41. Bearing cover, 42. Oil drain port, 43. Second worm support bearing, 44. Eddy current displacement sensor, 45. Armored thermocouple, 46. Piezoelectric pressure sensor, 47. Worm bracket, 48. Threaded joint, 49. Auxiliary plunger, 50. Plunger bracket, 51. Auxiliary plunger shoe, 52. Cavity oil temperature sensor mounting hole, 5 3. Box base, 54. First coupling, 55. Torque meter, 56. Torque meter mounting seat, 57. Second coupling, 58. Motor mounting seat, 59. Hydraulic motor, 60. Eddy current displacement sensor mounting hole, 61. Armored thermocouple mounting hole, 62. Piezoelectric pressure sensor mounting hole, 63. Eddy current displacement sensor positioning hole, 64. Armored thermocouple positioning hole, 65. Piezoelectric pressure sensor positioning hole, 66. Pressure sensor oil inlet hole. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0017] like Figure 1As shown, a 360-degree oil film morphology test device for a plunger pair is shown, wherein the swash plate shaft 1 is the main input shaft, and the swash plate and the input shaft are an integrated structure, forming the swash plate shaft 1; the swash plate shaft 1 is supported by a single-row angular contact ball bearing 7 and a double-row angular contact ball bearing 10, and the inner rings of the two bearings are positioned by a small bearing sleeve 9, and the small bearing sleeve 9 has two small oil holes on the upper and lower sides, and the outer rings of the two bearings are positioned by the step holes on the large bearing sleeve 6, and the right end of the inner ring of the double-row angular contact ball bearing 10 is positioned by the shoulder of the swash plate shaft 1, and the left end of the single-row angular contact ball bearing 7 is axially fixed and pre-tightened by a stop washer 4 and a round nut 3; the large bearing sleeve 6 and the bearing end cover 5 are fixed to the left end of the experimental box 40 by bolts, and the swash plate shaft 1 and the bearing end cover 5 are sealed by a lip seal ring 2, and the outer edge of the large bearing sleeve 6 is sealed by a seal ring 8; the above components constitute a swash plate shaft assembly except for the experimental box 40;

[0018] In the experimental oil chamber 11, the plunger bracket 50 is connected to the bottom of the experimental oil chamber 11 by bolts, an oil inlet passage is opened in the plunger bracket 50, one end of the threaded joint 48 is connected to the oil inlet passage through the through hole at the bottom of the box body 40, and the other end is connected to the oil supply branch pipe 39; the top of the plunger bracket 50 is connected to the cylinder support seat 16 by bolts; the first cylinder support bearing 17 supporting the cylinder body is installed on the right side of the cylinder support seat 16; the left end of the cylinder body 15 passes through the first cylinder support bearing 17 and is rotatably connected to the cylinder support seat 16; the inner ring of the first cylinder support bearing 17 is connected to the cylinder body 15 The shaft shoulder is fixed, and its outer ring is fixed by the step hole of the rigid support seat 16; the right end of the cylinder body 15 is rotatably connected with the bearing seat 29 through the second cylinder support bearing 28; the inner ring of the second cylinder support bearing 28 is fixed by the step surface of the right end of the cylinder body 15, and the outer ring is fixed by the step hole of the bearing seat 29, and its left side and outer edge are sealed by the second bearing side sealing ring 26 and the second bearing outer ring sealing ring 27 respectively; the shaft section on the right side of the cylinder body 15 shaft shoulder is connected to the worm wheel 18 through a thin flat key, and the axial positioning of the worm wheel 18 and the inner ring positioning of the second cylinder support bearing 28 are realized through the sleeve 25;

[0019] The worm wheel 18 cooperates with the worm 19 above it to form a worm gear pair; Figure 2 As shown, the worm 19 is installed on the worm bracket 47 through the first worm support bearing 20 and the second worm support bearing 43, the inner rings of the two bearings are fixed by the shaft shoulder of the worm 19, the outer ring of the first worm support bearing 20 is fixed by the bearing cover 24, and the outer ring of the second worm support bearing 43 is fixed by the bearing cover 41; the bearing cover 24 and the bearing cover 41 are connected to the worm bracket 47 by bolts; one end of the worm 19 extends out of the experimental box 40 through the through hole on the experimental box 40, and is connected to the stepper motor 21 through the stepper motor coupling 22; the stepper motor 21 is fixed to the stepper motor bracket 23 by four small bolts, and the stepper motor bracket 23 is connected to the outer wall of the experimental box 40 by bolts;

[0020] like Figure 1 As shown, a stepped hole is opened inside the cylinder body 15 for installing the bushing 14, and the bushing 14 is in clearance with the test plunger 13; a plunger cavity is opened inside the plunger bracket 50, and an auxiliary plunger 49 is installed on the left side, parallel to the test plunger 13; the right side inside the cylinder body 15 is an oil inlet pipe hole, which is in clearance with the left end of the oil inlet pipe 34; the middle section of the oil inlet pipe 34 is sealed and connected to the right side of the bearing seat 29 through the bearing seat sealing ring 30; the right end of the oil inlet pipe 34 is pressed on the oil inlet pipe sleeve 33 through two semicircular oil inlet pipe pressing plates 32, and the two semicircular oil inlet pipe pressing plates 32 are pressed on the oil inlet pipe sleeve 33. The semicircular oil introduction pipe pressure plate 32 and the oil introduction pipe sleeve 33 are fixed in the concave hole on the left side of the sealing cover 31 by bolts; the oil introduction pipe sleeve 33 and the sealing sleeve 31 are sealed by a sealing ring 38; the bearing seat 29 is fixed to the left end of the sealing cover 31 by bolts; the sealing cover 31 is connected to the right outer wall of the experimental box 40 by bolts; the right end of the sealing cover 31 is installed with a diverter block 35 by four bolts, and the through hole of the diverter block 35 is coaxial with the central hole of the sealing cover 31; the lower part of the diverter block 35 is connected to the oil supply branch pipe 39 by threading;

[0021] like Figure 2 As shown, the right end of the through hole of the diverter block 35 is connected to the oil inlet pipe 37 of the oil supply pipeline through a thread, and a pressure sensor 36 is installed at the rear to monitor the pressure of the oil supply pipeline; the oil inlet pipe 37, the diverter block 35, the center hole of the sealing cover 31, the oil introduction pipe 34, the oil introduction pipe sleeve 33, the oil introduction pipe pressure plate 32, the oil supply branch pipe 39, and the threaded joint 48 constitute the oil supply pipeline; the front end of the experimental oil chamber 11 is provided with an oil drain port 42 through a thread; the hydraulic drive motor 59 is fixed to the motor mounting seat 58 by bolts, and the motor mounting seat 58 is connected to the experimental box body 40 by bolts; the output shaft of the hydraulic motor 59 is connected to the torque meter 55 through the second coupling 57, and the torque meter 55 is connected to the swash plate shaft 1 through the first coupling 54; the torque meter 55 is fixed to the torque meter mounting seat 56, and the torque meter mounting seat 56 is connected to the experimental box body 40 by bolts; the entire experimental box body 40 is fixed to the box body bottom frame 53 by bolts;

[0022] like Figure 1 As shown, a cavity oil temperature sensor mounting hole 52 is opened at the rear end of the experimental oil cavity 11;

[0023] like Figure 3 As shown, three rows of sensor mounting holes are processed in parallel on the left surface of the cylinder body 15, which are two eddy current displacement sensor mounting holes 60, three armored thermocouple mounting holes 61, and three piezoelectric pressure sensor mounting holes 62. The same type of sensor mounting holes are distributed along the axial direction of the cylinder body, and the center distance is 15mm. Different types of sensors are distributed 45° apart in the circumferential direction.

[0024] like Figure 4As shown, three rows of sensor positioning holes are processed in parallel on the surface of the bushing 14, which are two eddy current displacement sensor positioning holes 63, three armored thermocouple positioning holes 64, and three piezoelectric pressure sensor positioning holes 65. A pressure sensor oil inlet hole 66 is processed in the center of each pressure sensor positioning hole 65, which is connected to the inside of the bushing 14; the positioning holes of sensors of the same type are distributed along the axial direction of the cylinder body, with a center distance of 15 mm, and sensors of different types are distributed 45° apart in the circumferential direction.

[0025] The helix angle of the worm 19 is 3.22°, and it can achieve self-locking. The worm wheel 18 can only be driven to rotate by the worm 19, thereby driving the cylinder body 15 to rotate through the thin flat key, while the cylinder body 15 cannot in turn drive the worm 19 to rotate through the worm wheel 18; the worm 19 is connected to the stepper motor 21 through the stepper motor coupling 22. Through the self-locking of the stepper motor 21 and the self-locking of the worm wheel 18 and the worm 19 themselves, it can be ensured that the cylinder body 15 does not rotate around the axis during a test, thereby avoiding affecting the test results.

[0026] The thickness of the oil film layer between the bushing 14 and the test plunger 13 changes rapidly, the oil film pressure is high, and the working environment is relatively harsh, so the eddy current method is selected to measure the oil film thickness; the eddy current displacement sensor 44 is installed flush with the inner wall of the bushing 14; the test plunger 13 is cylindrical, and a circle can be determined based on two points and a radius, so if the cylinder body 15 cannot rotate, at least four displacement sensors are required to measure the offset of the plunger in two planes in the axial direction, thereby calculating the inclination of the plunger and obtaining the distribution of the oil film thickness; and the present technical solution uses a rotatable cylinder body 15, and only two eddy current displacement sensors 44 need to be arranged in one axial direction. After two measurements, the two sets of data measured when the cylinder body 15 is at different angles are Synthesis, thereby obtaining the same effect as the above-mentioned four sensor tests; when the cylinder body cannot rotate, only the data of four positions at two fixed circumferential angles can be measured. The technical solution rotates the cylinder body 15 through the worm gear 18 and worm 19, measures the data multiple times, and synthesizes it, so that the eddy current displacement sensor 44 can measure the oil film thickness at any circumferential angle, thereby reducing the use of mathematical means and making the measurement results of the circumferential oil film morphology more intuitive and more in line with the actual situation; the axial direction of the oil film still needs to be calculated by mathematical means to obtain the morphology of the entire oil film; the number of eddy current displacement sensors can also be increased in the axial direction to measure nonlinear data, so that the obtained oil film thickness data is more accurate.

[0027] The measurement of oil film temperature considers using armored thermocouples and adopts non-contact measurement method. The armored thermocouple positioning hole 64 on the bushing 14 is not pierced. During the test, the inner surface of the bushing 14 is directly in contact with the oil film. When the oil film temperature reaches an equilibrium, the temperature distribution of the oil film layer is the same as the temperature distribution of the inner wall of the bushing 14. Since the temperature transfer in the metal parts only needs to consider heat conduction, it is relatively easy to analyze. Therefore, the temperature distribution of the oil film layer can be inferred based on the temperature of the measuring point measured in the bushing 14, the thermal physical properties of the material itself, and the temperature transfer method.

[0028] Since the oil film pressure between the test plunger 13 and the bushing 14 changes all the time, when the rotation speed of the swash plate shaft 1 is high, the frequency of pressure change is also high, so a piezoelectric pressure sensor is selected for measurement; according to the pressure measurement principle of the sensor, the required data can only be measured when the oil pressure of the oil film acts on the pressure sensor, so each pressure measuring point, that is, the center of the piezoelectric pressure sensor positioning hole 65 on the bushing 14, is processed with a pressure sensor oil inlet hole 66 so that the pressure oil can act on the sensor.

[0029] During the test, the stepper motor 21 is self-locked, and the worm gear 18 and worm 19 are self-locked and the first cylinder support bearing 17 and the second cylinder support bearing 28 are fixed, so that the cylinder 15 cannot move in the circumferential and axial directions; the external oil supply pipeline provides pressure oil to the plunger cavity of the test plunger 13 and the auxiliary plunger 49, pressing the test plunger slipper 12 and the auxiliary plunger slipper 51 on the swash plate surface, and forming a static pressure support at the same time; the hydraulic motor 59 drives the swash plate shaft 1 to rotate, and the rotation of the swash plate surface makes the test plunger 13 The auxiliary plunger 49 reciprocates to simulate the real pump oil suction and discharge, and after reaching equilibrium, record the temperature, pressure, displacement and other data; stop the hydraulic motor 59, wait for the whole system to stop running, start the stepper motor 21, make the cylinder 15 rotate a certain angle, stop the stepper motor 21 and self-lock, start the hydraulic motor 59 again, and repeat the above test; repeat this process, record multiple groups of data on the oil film characteristics of the cylinder 15 at different angles, and synthesize them to finally obtain the characteristics of the oil film in the entire plunger cavity.

Claims

1. A 360-degree oil film morphology testing device for a plunger pair, comprising a hydraulic drive motor (59), a torque meter (55), and a swash plate shaft assembly; it also comprises an experimental box (40), the left end opening of the box (40) is provided with a swash plate shaft (1); a plunger bracket (50) is provided at the bottom of the box (40), and a cylinder support seat (16) is provided above the plunger bracket; a sealing cover (31) is provided at the right end opening of the box (40), and a bearing seat (29) is provided at the left end of the sealing cover (31); the cylinder support seat (16) and the bearing seat (29) are provided with bearings respectively for supporting the cylinder (15); the right side of the box (40) is provided with an oil supply pipeline; the experimental box (40) is a two-cavity shell structure, the larger cavity on the right side is the experimental oil cavity (11), and the smaller cavity on the left side is the experimental oil cavity (11). Used to install the swash plate shaft assembly; the swash plate and the main shaft are integrated into a structure, and together with a double-row angular contact ball bearing (10) and a single-row angular contact ball bearing (7), a large bearing sleeve (6), a small bearing sleeve (9) and a bearing end cover (5) form a swash plate shaft assembly, which is sealed and connected to the experimental box (40) by bolts; a round nut installation groove is opened on a section of the swash plate shaft (1), and the single-row angular contact ball bearing (7) is pre-tightened by using a round nut (3) and a locking washer (4); a key groove is opened on the left end of the swash plate shaft, and is connected to the torque meter (55) through a first coupling (54); the torque meter (55) is further connected to the hydraulic drive motor (59) through a second coupling (57); in the experimental oil chamber (11), the plunger bracket (50) is installed at the bottom by bolts, and the cylinder body The support seat (16) is connected to the plunger bracket (50) by bolts; a positioning shoulder is provided in the middle of the cylinder body (15), and the left side of the shoulder is connected to the cylinder body support seat (16) through a support bearing A (17); the surface of the cylinder body (15) is processed with mounting holes for an eddy current displacement sensor (44), an armored thermocouple (45), and a piezoelectric pressure sensor (46); a stepped hole is made inside the cylinder body (15), and the left end is divided into a positioning hole for installing a bushing (14), and the right end is divided into an oil guide pipe hole; a test bushing (14) is installed at the left end inside the cylinder body (15), and the surface of the bushing (14) is processed with an eddy current displacement sensor positioning hole (63), an armored thermocouple positioning hole (64), and a piezoelectric pressure sensor positioning hole (65); three sensors are installed on the cylinder body (15), and the cylinder body (15) The right end is rotatably connected to the bearing seat (29) through the second support bearing (28), and a through hole is opened in the center of the bearing seat (29); an auxiliary plunger (49) is installed on the left side of the plunger bracket (50), which is parallel to the upper test plunger (13); an oil introduction channel is opened inside the plunger bracket (50), which is connected to the oil supply pipeline branch (39) below the box body (40); there is an opening on the right side of the experimental oil chamber (11), and the opening is sealed and connected to the box body sealing cover (31); the left end of the sealing cover (31) is hollow, and an oil introduction pipe sleeve (33) is installed in the middle, and the left oil introduction pipe (34) is fixed on the oil introduction pipe sleeve (33) through two semicircular oil introduction pipe pressure plates (32), and the pressure plate (32) and the oil introduction pipe sleeve (33) are fixed in the hole of the sealing cover (31) by bolts;The left end of the oil guide pipe (34) passes through the through hole of the bearing seat (29) and enters the cylinder body (15), and the outer diameter of the left end thereof is clearance-matched with the inner diameter of the right end of the cylinder body (15); a flow divider block (35) is installed on the right end of the sealing cover (31) through a thread, and the right end of the flow divider block (35) is connected to the oil inlet pipe (37) to form an oil supply pipeline; a pressure sensor (36) is installed on the rear side of the flow divider block (35); A worm wheel (18) is mounted on the right shaft section of the middle shaft shoulder of the cylinder body (15) through a thin flat key. The worm wheel (18) cooperates with the upper worm (19). The worm (19) is driven by a stepper motor and can drive the cylinder body (15) to rotate 360 ​​degrees. The worm (19) is mounted on the worm support (47) through a first worm support bearing (20) and a second worm support bearing (43). The inner rings of the two bearings are fixed through the shaft shoulder of the worm (19). The outer ring of the first worm support bearing (20) is fixed through a bearing cover (24). The outer ring of the second worm support bearing (43) is fixed by a bearing cover (41); the bearing cover (24) and the bearing cover (41) are connected to the worm support (47) by bolts; one end of the worm (19) extends out of the experimental box (40) through a through hole on the experimental box (40) and is connected to the stepper motor through a stepper motor coupling (22); the stepper motor is fixed to the stepper motor support (23) by four small bolts, and the stepper motor support (23) is connected to the outer wall of the experimental box (40) by bolts.

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