A double-station hydraulic cylinder seal test system with eccentric load and test method thereof

Abstract

The present invention discloses a double-station hydraulic cylinder sealing test system with eccentric loading, wherein the driving hydraulic circuit comprises a driving cylinder, a variable pump for controlling the system flow of the driving hydraulic circuit and a first proportional relief valve for controlling the system pressure of the driving hydraulic circuit, the tested cylinder hydraulic circuit comprises two tested cylinders arranged in parallel and a second proportional relief valve for controlling the internal pressure of the tested cylinder, the piston rod of the tested cylinder is connected to the piston rod of the driving cylinder via a tension pressure sensor, the eccentric loading system comprises an air compressor, a pneumatic stop valve, a pressure reducing valve and two loading cylinders, the speed of the tested cylinder can be controlled by the loading driving force of the driving cylinder and the precise control of the output flow and displacement detection feedback, the reciprocating motion of the hydraulic cylinder at different speeds can be simulated, and the sealing performance at different speeds can be examined.

Description

Technical Field

[0001] The present patent application relates to the technical field of hydraulic cylinder sealing performance testing, and in particular to a double-station hydraulic cylinder sealing testing system with eccentric loading and a testing method thereof. Background Art

[0002] If there is a lack of control over the key variables that affect the installation and operation of hydraulic cylinder reciprocating seals, the test results of hydraulic cylinder sealing performance will be unpredictable. In order to obtain comparative data on hydraulic cylinder sealing performance and provide a basis for the design and selection of seals, the test subjects of the seals should strictly control these key variables and strictly require the test conditions.

[0003] The hydraulic cylinder sealing performance test method and equipment mainly use specially designed test devices to achieve control such as applying pressure loads with specific changing cycles, high oil temperature environment, high and low speed reciprocating motion, etc. to the tested hydraulic cylinder seals, simulating the actual working conditions of the seals for testing, and measuring and recording the friction characteristics, wear, leakage and other key performance indicators of the seals during the test. The test results provide a scientific basis for the comprehensive performance evaluation and application selection of seals. In the actual operation of hydraulic cylinders, eccentric loading often occurs, which is easy to damage the seals. In the past, it was generally difficult to achieve sealing performance tests under eccentric loading conditions, and the test efficiency was low, which easily resulted in large resource and energy consumption. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of this patent application is to provide a double-station hydraulic cylinder seal test system with eccentric load and a test method thereof to solve the above-mentioned problems of the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A double-station hydraulic cylinder sealing test system with eccentric loading includes a test bench and a hydraulic system and an eccentric loading system installed on the test bench, the hydraulic system includes a driving hydraulic circuit and a test cylinder hydraulic circuit, the driving hydraulic circuit includes a driving cylinder, a variable pump for controlling the system flow of the driving hydraulic circuit and a first proportional relief valve for controlling the system pressure of the driving hydraulic circuit, the test cylinder hydraulic circuit includes two test cylinders arranged in parallel and a second proportional relief valve for controlling the internal pressure of the test cylinders, the piston rod of the test cylinder is connected to the piston rod of the driving cylinder through a tension pressure sensor, the eccentric loading system includes an air compressor, a pneumatic stop valve, a pressure reducing valve and two loading cylinders, the air is compressed by the air compressor and input into the two loading cylinders after being controlled by the pressure of the pressure reducing valve, and the eccentric load pressure is applied to the piston rods of the two test cylinders respectively, and the pneumatic stop valve controls the opening and closing of the loading force output by the loading cylinder.

[0007] Furthermore, the driving hydraulic circuit also includes an electromagnetic reversing valve connected to the two oil ports of the driving cylinder, the A and B ports of the electromagnetic reversing valve are respectively connected to the two oil ports of the driving cylinder through the first stop valve, the oil outlet of the variable pump is connected to the P port of the electromagnetic reversing valve through the first one-way valve, the oil outlet of the variable pump is also connected to the oil inlet of the first proportional relief valve through the first one-way valve, the oil outlet of the first proportional relief valve and the oil inlet of the variable pump are respectively connected to the first filter, and the first filter is connected to the first oil tank.

[0008] Furthermore, the driving hydraulic circuit also includes two first pressure measuring joints respectively connected to the A and B ports of the electromagnetic reversing valve, wherein one of the first pressure measuring joints is connected to the first pressure gauge, and the other first pressure measuring joint is connected to the pressure sensor.

[0009] Furthermore, the hydraulic circuit of the test cylinder also includes a metering pump, the oil outlet of the metering pump is connected to the oil inlet of the automatic overflow valve and the oil inlet of the second stop valve through a second one-way valve, the oil outlet of the second stop valve is respectively connected to the oil inlets of the two test cylinders, the oil outlet of the test cylinder is connected to the oil inlet of the third stop valve, the oil outlets of the two third stop valves are connected to the oil inlet of the second proportional overflow valve, and the oil inlet of the metering pump, the oil outlet of the automatic overflow valve and the oil outlet of the second proportional overflow valve are respectively connected to the second oil tank through a second filter.

[0010] Furthermore, the oil outlet of the metering pump is also connected to a second pressure measuring joint through a second one-way valve, the second pressure measuring joint is connected to a second pressure gauge, and the oil outlet of the test cylinder is also connected to a third pressure measuring joint, the third pressure measuring joint is connected to a third pressure gauge.

[0011] Furthermore, oil leakage receiving cups are provided at both ends of the tested cylinder.

[0012] Furthermore, the test bench includes a basic platform, two groups of test cylinder fixing frames for fixing the test cylinder are installed on one side of the upper end of the basic platform, and two groups of guide rails are installed on the other side of the upper end of the basic platform. No less than one slider is slidably connected to the guide rail, and the upper ends of multiple sliders on the same guide rail are connected to the same slider connecting plate, and the upper ends of the two slider connecting plates are connected to the same connecting end seat, the outward end of the piston rod of the test cylinder is connected to one end of the tension and pressure sensor connecting rod through a first connecting earring, a first rod head connecting tool and a first connecting pin, the tension and pressure sensor is installed on the tension and pressure sensor connecting rod, and the other end of the tension and pressure sensor connecting rod is connected to a connecting rod support installed on the slider connecting plate, the outward end of the piston rod of the driving cylinder is connected to the connecting seat through a second connecting earring, a second rod head connecting tool and a second connecting pin, and the connecting seat is connected to the side wall of the connecting end seat.

[0013] Furthermore, the upper ends of the two slider connecting plates are connected to the same loading cylinder fixing frame, and the loading cylinder located directly above the tested cylinder is installed in the loading cylinder fixing frame.

[0014] Furthermore, a displacement sensor is fixedly connected to the side wall of the base platform, and the sensing end of the sensing magnetic ring on the displacement sensor is fixed to the slider connecting plate through a bracket.

[0015] A test method for the double-station hydraulic cylinder seal test system with eccentric load as described above comprises the following steps:

[0016] S1. Assemble the test cylinder according to the test requirements, and start the driving hydraulic circuit and the test cylinder hydraulic circuit through computer control;

[0017] S2. Regulate the variable pump to control the system flow of the driving hydraulic circuit, regulate the first proportional relief valve to control the system pressure of the driving hydraulic circuit, and control the reversing of the electromagnetic reversing valve through a computer to achieve the reciprocating motion of the piston rod on the driving cylinder. The change of the flow of the driving hydraulic system can control the reciprocating speed of the driving cylinder. By adjusting the output flow of the variable pump through the displacement change fed back by the displacement sensor, the reciprocating speed can be precisely controlled, thereby meeting the test requirements under different driving reciprocating speeds;

[0018] S3. When the driving hydraulic circuit is controlled to be tested according to the steps in S2, since the outward end of the piston rod of the tested cylinder is connected to the driving cylinder through the tension pressure sensor, and the driving cylinder piston rod is connected through the second connecting earring and the connecting end seat and the connecting seat, as the driving cylinder piston rod reciprocates, all the connecting structural parts on the slider connecting plate (including the piston rod of the tested cylinder) reciprocate along the guide rail, and the tension pressure sensor detects the reciprocating driving force output by the driving cylinder in real time. The change of the driving force can directly reflect the change of the friction between the seal and the piston rod in the tested cylinder, so as to judge the change of the sealing performance by the change of the friction;

[0019] S4. When the driving cylinder drives the piston rod of the tested cylinder to reciprocate, adjust the direct-acting relief valve in the hydraulic circuit of the tested cylinder to set the maximum system pressure as the system safety control pressure; adjust the second proportional relief valve in the hydraulic circuit of the tested cylinder to control the internal pressure of the tested cylinder. The pressure can be set in a constant pressure form or a dynamic pulse pressure form to meet various test requirements. At this time, the driving cylinder can carry the double-station tested cylinder to perform a hydraulic cylinder sealing test under a specific test pressure (internal pressure of the tested cylinder);

[0020] S5. The opening and closing of the loading cylinder output loading force can be controlled by opening and closing the pneumatic stop valve, adjusting the pressure of the pressure reducing valve, changing the eccentric load pressure on the piston rod of the tested cylinder, and changing the eccentric load force to meet the needs of various eccentric load forces; when the pneumatic stop valve is opened, the eccentric load force from the loading cylinder is applied to the piston rod of the tested cylinder, thereby realizing the double-station hydraulic cylinder sealing test with eccentric load;

[0021] S6. During the test, the driving force provided by the driving cylinder is detected to reflect the change in the friction force of the seal of the tested cylinder. At the same time, the oil leakage is received at both ends of the tested cylinder to test the leakage amount.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Through the loading driving force of the driving cylinder, as well as the precise control of the output flow and displacement detection feedback, the speed of the tested cylinder can be controlled, the reciprocating motion of the hydraulic cylinder at different speeds can be simulated, and the performance of the seal at different speeds can be examined;

[0024] 2. By loading the cylinder, adjusting the loading force change can control the eccentric load, simulate the eccentric load condition of the hydraulic cylinder, and adjust the eccentric load force according to different eccentric load pressures;

[0025] 3. Through the setting of double working stations, one driving cylinder can drive two tested cylinders to reciprocate, thus realizing the test of multiple sets of seals and improving the test efficiency;

[0026] 4. By controlling the pressure of the proportional relief valve in the hydraulic circuit of the tested cylinder, the pressure can be set to a constant pressure or a dynamic pulse pressure to meet various test requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the hydraulic principle of the present invention;

[0028] Figure 2 This is a schematic diagram of the driving hydraulic circuit principle of the present invention;

[0029] Figure 3 It is a schematic diagram of the principle of the hydraulic circuit of the tested cylinder of the present invention;

[0030] Figure 4 It is a schematic diagram of the principle of the eccentric loading system of the present invention;

[0031] Figure 5 It is a schematic diagram of the three-dimensional structure of the test bench of the present invention;

[0032] Figure 6 This is a schematic diagram of the three-dimensional structure of the test bench of the present invention from another perspective;

[0033] Figure 7 For the present invention Figure 5 Schematic diagram of the side structure.

[0034] Description of the accompanying symbols: driving hydraulic circuit 1, first filter 11, variable pump 12, first non-return valve 13, first proportional relief valve 14, electromagnetic reversing valve 15, first stop valve 16, driving cylinder 17, first pressure measuring joint 18, pressure sensor 19, tested cylinder hydraulic circuit 2, second filter 21, quantitative pump 22, second non-return valve 23, automatic relief valve 24, second proportional relief valve 25, oil leakage receiving cup 26, second stop valve 27, tested cylinder 28, third stop valve 29, second pressure measuring joint 210, third pressure measuring joint 211, Offset loading system 3, air compressor 31, pneumatic stop valve 32, pressure reducing valve 33, loading cylinder 34, test bench 4, basic platform 41, test cylinder fixing frame 42, drive cylinder fixing seat 43, loading cylinder fixing frame 44, tension and pressure sensor connecting rod 45, connecting rod support 46, first rod head connecting tooling 47, first connecting earring 48, first connecting pin 49, connecting end seat 410, connecting seat 411, guide rail 412, slider 413, slider connecting plate 414, displacement sensor 415, bracket 416, tension and pressure sensor 5. DETAILED DESCRIPTION

[0035] The following describes the implementation of the present patent application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present patent application from the content disclosed in this specification. The present patent application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present patent application. It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict.

[0036] See also Figure 1-7 , the present invention provides a technical solution:

[0037] A double-station hydraulic cylinder seal test system with eccentric load, such as Figure 1 and Figure 5 As shown, it includes a test bench 4 and a hydraulic system and an eccentric load loading system 3 installed on the test bench 4, and the hydraulic system includes a driving hydraulic circuit 1 and a test cylinder hydraulic circuit 2.

[0038] like Figure 2As shown, the driving hydraulic circuit 1 includes a driving cylinder 17, a variable pump 12 for controlling the system flow of the driving hydraulic circuit 1, and a first proportional relief valve 14 for controlling the system pressure of the driving hydraulic circuit 1. The driving hydraulic circuit 1 also includes an electromagnetic reversing valve 15 connected to two oil ports of the driving cylinder 17. The A and B ports of the electromagnetic reversing valve 15 are respectively connected to the two oil ports of the driving cylinder 17 through a first stop valve 16. The oil outlet of the variable pump 12 is connected to the P port of the electromagnetic reversing valve 15 through a first check valve 13. The oil outlet of the variable pump 12 is also connected to the oil inlet of the first proportional relief valve 14 and the fourth pressure measuring joint through the first check valve 13. The fourth pressure measuring joint is connected to the pressure instrument for system pressure detection, the oil outlet of the first proportional relief valve 14 and the oil inlet of the variable pump 12 are respectively connected to the first filter 11, and the T port of the electromagnetic reversing valve 15 is also connected to a third filter. The effect of the third filter is return oil filtering. The two first filters 11 are connected to the first oil tank. The driving hydraulic circuit 1 also includes two first pressure measuring joints 18 respectively connected to the A and B ports of the electromagnetic reversing valve 15, one of the first pressure measuring joints 18 is connected to the first pressure gauge, and the other first pressure measuring joint 18 is connected to the pressure sensor 19, which is used to test the pressure of the two oil ports of the driving cylinder 17.

[0039] The electromagnetic reversing valve 15 is a two-position four-way reversing valve, wherein the A and B ports are the working oil ports connected to the drive cylinder 17, the P port is the oil inlet port connected to the oil from the variable pump 12, and the T port is the oil return port connected to the oil return direction.

[0040] like Figure 3 As shown, the tested cylinder hydraulic circuit 2 includes two tested cylinders 28 arranged in parallel and a second proportional relief valve 25 for controlling the internal pressure of the tested cylinder 28. The piston rod of the tested cylinder 28 is connected to the piston rod of the driving cylinder 17 through the tension pressure sensor 5. The tested cylinder hydraulic circuit 2 also includes a metering pump 22. The oil outlet of the metering pump 22 is connected to the oil inlet of the automatic relief valve 24 and the oil inlet of the second stop valve 27 through the second one-way valve 23. The oil outlet of the second stop valve 27 is connected to the oil inlets of the two tested cylinders 28 respectively. The oil outlet of the tested cylinder 28 is connected to the oil inlet of the third stop valve 29. The oil outlets of the two third stop valves 29 are connected to the second The oil inlet of the proportional relief valve 25, the oil inlet of the metering pump 22, the oil outlet of the automatic relief valve 24 and the oil outlet of the second proportional relief valve 25 are respectively connected to the second oil tank through the second filter 21. The oil outlet of the metering pump 22 is also connected to the second pressure measuring joint 210 through the second one-way valve 23. The second pressure measuring joint 210 is connected to a second pressure gauge for detecting the system pressure. The oil outlet of the test cylinder 28 is also connected to a third pressure measuring joint 211. The third pressure measuring joint 211 is connected to a third pressure gauge for detecting the oil port pressure of the test cylinder 28. Oil leakage receiving cups 212 are provided at both ends of the test cylinder 28 for receiving leakage generated by the test.

[0041] like Figure 4 As shown, the eccentric loading system 3 includes an air compressor 31, a pneumatic stop valve 32, a pressure reducing valve 33 and two loading cylinders 34. The air is compressed by the air compressor 31 and input into the two loading cylinders 34 through the pressure control of the pressure reducing valve 33, and the eccentric load pressure is applied to the piston rods of the two test cylinders 28 respectively. The pneumatic stop valve 32 controls the opening and closing of the loading force output by the loading cylinder 34.

[0042] like Figure 5 and Figure 6 As shown, the test bench 4 includes a basic platform 41, two sets of test cylinder fixing frames 42 for fixing the test cylinder 28 are installed on one side of the upper end of the basic platform 41, and two sets of guide rails 412 are installed on the other side of the upper end of the basic platform 41. The guide rails 412 are slidably connected with at least one slider 413, and the upper ends of multiple sliders 413 on the same guide rail 412 are connected to the same slider connecting plate 414, and the upper ends of the two slider connecting plates 414 are connected to the same connecting end seat 410. The outward end of the piston rod of the test cylinder 28 is connected to the tension and compression through the first connecting earring 48, the first rod head connecting tool 47 and the first connecting pin 49. One end of the force sensor connecting rod 45 is connected, the tension pressure sensor 5 is installed on the tension pressure sensor connecting rod 45, and the other end of the tension pressure sensor connecting rod 45 is connected to a connecting rod support 46 installed on the slider connecting plate 414. The outward end of the piston rod of the driving cylinder 17 is connected to the connecting seat 411 through a second connecting earring, a second rod head connecting tool and a second connecting pin. The connecting seat 411 is connected to the side wall of the connecting end seat 410. The upper ends of the two slider connecting plates 414 are connected to the same loading cylinder fixing frame 44. The loading cylinder 34 located directly above the test cylinder 28 is installed in the loading cylinder fixing frame 44. Figure 7 As shown, a displacement sensor 415 is fixedly connected to the side wall of the base platform 41 , and the sensing end of the sensing magnetic ring on the displacement sensor 415 is fixed to the slider connecting plate 414 through a bracket 416 .

[0043] The first rod head connecting fixture 47 and the second rod head connecting fixture are two rectangular plates detachably connected by locking nails, which facilitates the assembly between two adjacent structures.

[0044] In addition, during the test, the operation of the test system is controlled by a computer, and a temperature control system is configured to control the temperature of the test system, mainly including controlling electrical components such as the variable pump 12, the first one-way valve 13, the first proportional relief valve 14, the electromagnetic reversing valve 15, the first stop valve 16, the pressure sensor 19, the quantitative pump 22, the second one-way valve 23, the automatic relief valve 24, the second proportional relief valve 25, the second stop valve 27, the third stop valve 29, the air compressor 31, the pneumatic stop valve 32, and the pressure reducing valve 33. Computer control and temperature control are well known to those skilled in the art and are common knowledge, and will not be described one by one here.

[0045] A test method for the double-station hydraulic cylinder seal test system with eccentric load as above comprises the following steps:

[0046] S1. Assemble the test cylinder 28 according to the test requirements, and start the driving hydraulic circuit 1 and the test cylinder hydraulic circuit 2 through computer control;

[0047] S2, adjusting the variable pump 12 to control the system flow of the driving hydraulic circuit 1, adjusting the first proportional relief valve 14 to control the system pressure of the driving hydraulic circuit 1, and controlling the reversing of the electromagnetic reversing valve 15 by a computer, so as to realize the reciprocating motion of the piston rod on the driving cylinder 17. The change of the flow of the driving hydraulic system can control the reciprocating speed of the driving cylinder 17. By adjusting the output flow of the variable pump 12 through the displacement change fed back by the displacement sensor 415, the reciprocating speed can be precisely controlled, so as to meet the test requirements under different driving reciprocating speeds;

[0048] S3. When the driving hydraulic circuit is controlled to be tested according to the steps in S2, since the outward end of the piston rod of the tested cylinder 28 is connected to the driving cylinder 17 through the tension pressure sensor 5, the piston rod of the driving cylinder 17 is connected to the connecting end seat 410 and the connecting seat 411 through the second connecting earring. With the reciprocating movement of the piston rod of the driving cylinder 17, all the connecting structural parts on the slider connecting plate 414 (including the piston rod of the tested cylinder 28) reciprocate along the guide rail 412. The tension pressure sensor 5 detects the reciprocating driving force output by the driving cylinder 17 in real time. The change of the driving force can directly reflect the change of the friction between the seal and the piston rod in the tested cylinder 28, so as to judge the change of the performance of the seal by the change of the friction.

[0049] S4. When the driving cylinder 17 drives the piston rod of the tested cylinder 28 to reciprocate, the direct-acting relief valve 24 in the hydraulic circuit 2 of the tested cylinder is adjusted to set the maximum system pressure as the system safety control pressure; the second proportional relief valve 25 in the hydraulic circuit 2 of the tested cylinder is adjusted to control the internal pressure of the tested cylinder 28. The pressure can be set in a constant pressure form or a dynamic pulse pressure form to meet various test requirements. At this time, the driving cylinder 17 can be used with the double-station tested cylinder 28 to perform a hydraulic cylinder sealing test under a specific test pressure (internal pressure of the tested cylinder 28);

[0050] S5. The opening and closing of the loading force output by the loading cylinder 34 can be controlled by opening and closing the pneumatic stop valve 32, and the pressure of the pressure reducing valve 33 can be adjusted to change the bias load pressure applied to the piston rod of the tested cylinder 28, so as to meet the requirements of various bias load forces; when the pneumatic stop valve 32 is opened, the bias load force from the loading cylinder 34 is applied to the piston rod of the tested cylinder 28, thereby realizing the double-station hydraulic cylinder sealing test with bias load;

[0051] S6. During the test, the driving force provided by the driving cylinder 17 is detected to reflect the change in the friction force of the seal of the tested cylinder 28. At the same time, the leaking oil is received at both ends of the tested cylinder 28 to test the leakage amount.

[0052] The above embodiments are merely illustrative of the principles and effects of this patent application, and are not intended to limit this patent application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of this patent application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed in this patent application should still be covered by the claims of this patent application.

Claims

1. A double-station hydraulic cylinder seal test system with eccentric loading, comprising a test bench (4) and a hydraulic system and an eccentric loading system (3) installed on the test bench (4), characterized in that: The hydraulic system comprises a driving hydraulic circuit (1) and a test cylinder hydraulic circuit (2); the driving hydraulic circuit (1) comprises a driving cylinder (17), a variable pump (12) for controlling the system flow of the driving hydraulic circuit (1), a first proportional relief valve (14) for controlling the system pressure of the driving hydraulic circuit (1), and an electromagnetic reversing valve (15) connected to two oil ports of the driving cylinder (17); the test cylinder hydraulic circuit (2) comprises two test cylinders (28) arranged in parallel and a second proportional relief valve (25) for controlling the internal pressure of the test cylinders (28). 5), the piston rod of the tested cylinder (28) is connected to the piston rod of the driving cylinder (17) through a tension pressure sensor (5); the eccentric loading system (3) comprises an air compressor (31), a pneumatic stop valve (32), a pressure reducing valve (33) and two loading cylinders (34); the air is compressed by the air compressor (31) and input to the two loading cylinders (34) after being pressure-controlled by the pressure reducing valve (33), and the eccentric loading pressure is applied to the piston rods of the two tested cylinders (28) respectively, and the pneumatic stop valve (32) controls the opening and closing of the loading force output by the loading cylinder (34); The test cylinder hydraulic circuit (2) further comprises a metering pump (22), the oil outlet of the metering pump (22) being connected to the oil inlet of the automatic overflow valve (24) and the oil inlet of the second stop valve (27) via a second one-way valve (23), the oil outlet of the second stop valve (27) being connected to the oil inlets of the two test cylinders (28) respectively, the oil outlet of the test cylinder (28) being connected to the oil inlet of the third stop valve (29), the oil outlets of the two third stop valves (29) being connected to the oil inlet of the second proportional overflow valve (25), the oil inlet of the metering pump (22), the oil outlet of the automatic overflow valve (24) and the oil outlet of the second proportional overflow valve (25) being connected to the second oil tank respectively via a second filter (21).

2. A double-station hydraulic cylinder seal test system with eccentric load according to claim 1, characterized in that: The A and B ports of the electromagnetic reversing valve (15) are respectively connected to the two oil ports of the driving cylinder (17) through a first stop valve (16); the oil outlet of the variable pump (12) is connected to the P port of the electromagnetic reversing valve (15) through a first one-way valve (13); the oil outlet of the variable pump (12) is also connected to the oil inlet of a first proportional relief valve (14) through the first one-way valve (13); the oil outlet of the first proportional relief valve (14) and the oil inlet of the variable pump (12) are respectively connected to a first filter (11); and the first filter (11) is connected to a first oil tank.

3. A double-station hydraulic cylinder seal test system with eccentric load according to claim 2, characterized in that: The driving hydraulic circuit (1) also includes two first pressure measuring joints (18) respectively connected to ports A and B of the electromagnetic reversing valve (15), wherein one of the first pressure measuring joints (18) is connected to a first pressure gauge, and the other first pressure measuring joint (18) is connected to a pressure sensor (19).

4. A double-station hydraulic cylinder seal test system with eccentric load according to claim 1, characterized in that: The oil outlet of the metering pump (22) is also connected to a second pressure measuring joint (210) via a second one-way valve (23), and the second pressure measuring joint (210) is connected to a second pressure gauge. The oil outlet of the test cylinder (28) is also connected to a third pressure measuring joint (211), and the third pressure measuring joint (211) is connected to a third pressure gauge.

5. The double-station hydraulic cylinder seal test system with eccentric load according to claim 1, characterized in that: Oil leakage receiving cups (212) are provided at both ends of the tested cylinder (28).

6. The double-station hydraulic cylinder seal test system with eccentric load according to claim 1, characterized in that: The test bench (4) comprises a basic platform (41), two groups of test cylinder fixing frames (42) for fixing the test cylinder (28) are installed on one side of the upper end of the basic platform (41), two groups of guide rails (412) are installed on the other side of the upper end of the basic platform (41), at least one slider (413) is slidably connected to the guide rail (412), the upper ends of multiple sliders (413) on the same guide rail (412) are connected to the same slider connecting plate (414), the upper ends of the two slider connecting plates (414) are connected to the same connecting end seat (410), and the outward end of the piston rod of the test cylinder (28) is connected to the test cylinder (28) through The first connecting earring (48), the first rod head connecting tool (47) and the first connecting pin (49) are connected to one end of the tension pressure sensor connecting rod (45), the tension pressure sensor (5) is installed on the tension pressure sensor connecting rod (45), and the other end of the tension pressure sensor connecting rod (45) is connected to a connecting rod support (46) installed on the slider connecting plate (414), and the outward end of the piston rod of the driving cylinder (17) is connected to the connecting seat (411) through the second connecting earring, the second rod head connecting tool and the second connecting pin, and the connecting seat (411) is connected to the side wall of the connecting end seat (410).

7. A double-station hydraulic cylinder seal test system with eccentric load according to claim 6, characterized in that: The upper ends of the two slider connecting plates (414) are connected to the same loading cylinder fixing frame (44), and a loading cylinder (34) located directly above the tested cylinder (28) is installed in the loading cylinder fixing frame (44).

8. The double-station hydraulic cylinder seal test system with eccentric load according to claim 6, characterized in that: A displacement sensor (415) is fixedly connected to the side wall of the base platform (41), and the sensing end of the sensing magnetic ring on the displacement sensor (415) is fixed to the slider connecting plate (414) through a bracket (416).

9. A test method for a double-station hydraulic cylinder seal test system with eccentric load as claimed in any one of claims 6 to 8, characterized in that: The steps include: S1. Assemble the test cylinder (28) according to the test requirements, and start the driving hydraulic circuit (1) and the test cylinder hydraulic circuit (2) through computer control; S2, adjusting the variable pump (12) to control the system flow of the driving hydraulic circuit (1), adjusting the first proportional relief valve (14) to control the system pressure of the driving hydraulic circuit (1), controlling the reversal of the electromagnetic reversing valve (15) through a computer, thereby realizing the reciprocating motion of the piston rod on the driving cylinder (17), and controlling the reciprocating speed of the driving cylinder (17) by the change of the flow of the driving hydraulic system. By adjusting the displacement change fed back by the displacement sensor (415), the output flow of the variable pump (12) is realized to realize the precise control of the reciprocating speed, thereby meeting the test requirements under different driving reciprocating speeds; S3. When the driving hydraulic circuit is controlled to be tested according to the steps in S2, since the outward end of the piston rod of the tested cylinder (28) is connected to the driving cylinder (17) through the tension pressure sensor (5), the piston rod of the driving cylinder (17) is connected through the second connecting earring and the connecting end seat (410) and the connecting seat (411). As the piston rod of the driving cylinder (17) reciprocates, all the connecting structural parts on the slider connecting plate (414) reciprocate along the guide rail (412). The tension pressure sensor (5) detects the reciprocating driving force output by the driving cylinder (17) in real time. The change of the driving force directly reflects the change of the friction between the seal and the piston rod in the tested cylinder (28), so that the change of the performance of the seal is judged by the change of the friction. S4. When the driving cylinder (17) drives the piston rod of the tested cylinder (28) to reciprocate, the automatic relief valve (24) in the hydraulic circuit (2) of the tested cylinder is adjusted to set the maximum system pressure as the system safety control pressure; the second proportional relief valve (25) in the hydraulic circuit (2) of the tested cylinder is adjusted to control the internal pressure of the tested cylinder (28). At this time, the driving cylinder (17) can carry the double-station tested cylinder (28) to perform a hydraulic cylinder sealing test; S5, by opening and closing the pneumatic stop valve (32), the loading cylinder (34) is controlled to open and close the loading force output, and the pressure of the pressure reducing valve (33) is adjusted to change the bias load pressure applied to the piston rod of the cylinder under test (28). The bias load force changes to meet the requirements of various different bias load forces; when the pneumatic stop valve (32) is opened, the bias load force from the loading cylinder (34) is applied to the piston rod of the cylinder under test (28), thereby realizing the double-station hydraulic cylinder sealing test with bias load; S6. During the test, the driving force provided by the driving cylinder (17) is detected to reflect the change in the friction force of the seal of the tested cylinder (28). At the same time, leaking oil is received at both ends of the tested cylinder (28) to test the leakage amount.

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