A hydraulic cylinder testing system

Abstract

A hydraulic cylinder test system, the hydraulic cylinder test system includes hydraulic oil tank, motor, main pump, control pump, left servo valve, left hydraulic cylinder, base, limit block, right servo valve and right hydraulic cylinder, the hydraulic oil tank is in sequence with main pump, control pump communication, the motor is respectively with main pump, control pump electricity is connected, the oil outlet of main pump is communicated with the P port of left servo valve through P1 mouth, the A port of left servo valve is communicated with the A port of left one hydraulic control check valve, the B port of left one hydraulic control check valve is communicated with the rodless cavity of left hydraulic cylinder through A1 mouth, the rod cavity of left hydraulic cylinder is communicated with the B port of left two hydraulic control check valve through B1 mouth, the oil outlet of left two hydraulic control check valve is communicated with the B port of left servo valve, the T port of left servo valve is communicated with the hydraulic oil tank through T1 mouth, this design can meet the internal leakage test of hydraulic cylinder middle position and the synchronous control precision test of multiple hydraulic cylinders simultaneously through a set of test system.

Description

Technical Field

[0001] This invention relates to an improvement in hydraulic cylinder testing technology, belonging to the field of hydraulic systems, and particularly to a hydraulic cylinder testing system. Background Technology

[0002] Internal leakage testing of hydraulic cylinders is a crucial part of factory testing, directly impacting low-speed control accuracy. During the test, oil is introduced into the working chamber of the tested hydraulic cylinder, pressurized to the rated pressure, and the leakage amount through the piston to the other chamber is measured. Due to testing limitations, hydraulic cylinders can generally only undergo internal leakage testing at two extreme positions: when the piston rod is fully extended or retracted. However, hydraulic cylinders often operate in the middle stroke position. If internal leakage testing at the middle position is required, another hydraulic cylinder or a heavy object is needed to simulate loading, complicating the testing system. Furthermore, in servo hydraulic systems, multiple servo valves are often used to synchronously control multiple hydraulic cylinders. Once the internal leakage test of a single hydraulic cylinder passes, testing the synchronous control accuracy of two or more cylinders requires disassembly and replacement into another testing system, increasing operational difficulty and reducing efficiency.

[0003] Chinese patent application CN 202010377121.3, filed on May 7, 2020, discloses a hydraulic cylinder for a dual-cylinder synchronous load lateral force test bench. The fixed-displacement dual pump includes a plunger pump and a gear pump that draw oil from an oil tank. The oil tank is equipped with an air filter, a level / temperature gauge, and a shut-off valve. A return oil filter and a cooler are installed in the oil return circuit of the oil tank; an oil suction filter is installed in the oil circuit from the oil inlets of the plunger pump and gear pump to the oil tank. A first relief valve, a first directional valve, a second directional valve, a third directional valve, and a pressure sensor are connected to the oil outlet of the plunger pump. The first directional valve is connected to a second relief valve. The second directional valve is connected to the rod chamber and rodless chamber of the first tested cylinder via a first quick-connect coupling and a second quick-connect coupling, respectively. The rodless chamber of the first test cylinder is connected to a first flow meter, and the first flow meter is connected to a first flow sensor; the piston rod of the first test cylinder is connected to a first displacement sensor. However, the above technology does not solve the problem of the test system being complex and difficult to operate.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this patent application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of complex testing systems and high operation difficulty in the existing technology, and to provide a hydraulic cylinder testing system that is simple to operate and has low operation difficulty.

[0006] To achieve the above objectives, the technical solution of the present invention is: a hydraulic cylinder testing system, the hydraulic cylinder testing system comprising a hydraulic oil tank, an electric motor, a main pump, a control pump, a left servo valve, a left hydraulic cylinder, a base, a limit block, a right servo valve, and a right hydraulic cylinder;

[0007] The hydraulic oil tank is connected in sequence to the main pump and the control pump;

[0008] The electric motors are electrically connected to the main pump and the control pump, respectively.

[0009] The oil outlet of the main pump is connected to the P port of the left servo valve via port P1. The A port of the left servo valve is connected to the A port of the left hydraulic control check valve. The B port of the left hydraulic control check valve is connected to the rodless chamber of the left hydraulic cylinder via port A1.

[0010] The rod chamber of the left hydraulic cylinder is connected to the B port of the left second hydraulic control check valve via port B1. The oil outlet of the left second hydraulic control check valve is connected to the B port of the left servo valve. The T port of the left servo valve is connected to the hydraulic oil tank via port T1.

[0011] The oil outlet of the main pump is connected to the P port of the right servo valve via port P1. The A port of the right servo valve is connected to the A port of the right hydraulic control check valve. The B port of the right hydraulic control check valve is connected to the rodless chamber of the right hydraulic cylinder via port A1.

[0012] The rod chamber of the right hydraulic cylinder is connected to the B port of the right second hydraulic control check valve via port B1. The oil outlet of the right second hydraulic control check valve is connected to the B port of the right servo valve. The T port of the right servo valve is connected to the hydraulic oil tank via port T1.

[0013] Multiple sets of limiting blocks are installed on the top of the base, and a left hydraulic cylinder and a right hydraulic cylinder are set above the uppermost limiting block.

[0014] The cylinder barrels of the left and right hydraulic cylinders are connected to the upper synchronous beam, and the piston rods of the left and right hydraulic cylinders pass through the lower synchronous beam and are connected to the uppermost limiting block.

[0015] All the limit blocks are fixed to the base by two sets of studs and nuts, which are symmetrically arranged at the left and right ends of the limit blocks.

[0016] The top of the uppermost limiting block has two fixing plates connected by bolts.

[0017] Overflow valves are installed in the oil circuits between the control pump and the left hydraulic cylinder, and between the control pump and the right hydraulic cylinder.

[0018] The X ports of the first and second left hydraulic control check valves are connected to the A port of the left solenoid directional valve. The P port of the left solenoid directional valve is connected to the control pump via the R1 port. The T port of the left solenoid directional valve is connected to the hydraulic oil tank via the L1 port.

[0019] The Y ports of the first and second hydraulically controlled check valves on the left are connected to the hydraulic oil tank via port L1.

[0020] The first left hydraulic control check valve is connected to the first left relief valve, and the second left hydraulic control check valve is connected to the second left relief valve.

[0021] The first hydraulic control check valve on the left is equipped with a first pressure sensor, and the second hydraulic control check valve on the left is equipped with a second pressure sensor.

[0022] The X ports of the right first hydraulic control check valve and the right second hydraulic control check valve are connected to the A port of the right solenoid directional valve. The P port of the right solenoid directional valve is connected to the control pump via the R1 port. The T port of the right solenoid directional valve is connected to the hydraulic oil tank via the L1 port.

[0023] The Y ports of the right first hydraulic control check valve and the right second hydraulic control check valve are connected to the hydraulic oil tank via port L1.

[0024] The first right hydraulic control check valve is connected to the first right relief valve, and the second right hydraulic control check valve is connected to the second right relief valve.

[0025] The rightmost hydraulic control check valve is equipped with a rightmost pressure sensor, and the rightmost hydraulic control check valve is equipped with a rightmost pressure sensor.

[0026] The length of the upper synchronous beam is greater than the length of the lower synchronous beam.

[0027] The base includes a base plate and two columns. The top left and right ends of the base plate are connected to the bottom of the two columns respectively, and the upper synchronous beam is inserted into the upper end of the two columns.

[0028] The top of the base plate is provided with multiple sets of limiting blocks. All the limiting blocks are fixed to the base plate by two sets of studs and nuts. The two sets of studs and nuts are symmetrically arranged at the left and right ends of the limiting blocks.

[0029] The left and right hydraulic cylinders are each equipped with two sets of mounting lugs, and all mounting lugs are installed through the upper synchronous beam.

[0030] The piston rods of the left and right hydraulic cylinders pass through the lower synchronous beam and are connected to the corresponding fixed plates, respectively.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. In a hydraulic cylinder testing system of the present invention, the hydraulic oil tank is sequentially connected to the main pump and the control pump; the electric motor is electrically connected to the main pump and the control pump respectively; multiple sets of limiting blocks are installed on the top of the base, and the left and right hydraulic cylinders are arranged above the uppermost limiting block. No hydraulic cylinder loading or simulated heavy loading is required. A single testing system can simultaneously meet the internal leakage test of the middle position of the hydraulic cylinder and the synchronous control accuracy test of multiple hydraulic cylinders. The system has a high degree of integration, and can measure two extreme positions and the middle position without additional hydraulic cylinder loading or simulated heavy loading. Compared with existing technologies, the system is simplified without compromising the performance. Therefore, the testing system is simple, easy to operate, and highly efficient. Thus, this design makes the testing system simple and easy to use.

[0033] 2. In this invention, a hydraulic cylinder testing system comprises two hydraulic cylinders: the cylinder barrels of the left and right hydraulic cylinders are connected to the upper synchronous beam, and the piston rods of the left and right hydraulic cylinders pass through the lower synchronous beam and connect to the uppermost limiting block. All limiting blocks are fixed to the base by two sets of studs and nuts, symmetrically arranged at the left and right ends of the limiting blocks. The studs and nuts are used to fix the limiting blocks, and the height of the limiting blocks is adjusted and then locked with nuts. The height is adjusted by changing the number or thickness of the limiting blocks to accommodate the extension length of the piston rods. Bolts are used to connect and fix the piston rods and weights of the left and right hydraulic cylinders. Multiple tests can be performed directly without disassembly or reassembly, reducing operational difficulty. Therefore, this design is convenient to adjust and safe to use.

[0034] 3. In the hydraulic cylinder testing system of this invention, the base includes a base plate and two columns. The left and right ends of the top of the base plate are connected to the bottom of the two columns, respectively. An upper synchronous beam is inserted into the upper end of the two columns. The piston rods of the left and right hydraulic cylinders pass through the lower synchronous beam and are connected to the corresponding fixed plates. The installation of the columns, base plate, and fixed plates makes the installation of the left and right hydraulic cylinders more stable and the operation of the device safer. Therefore, this design is stable in operation and highly safe. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the oil circuit connection of the present invention.

[0036] Figure 2 This is the oil circuit diagram of the left servo valve in this invention.

[0037] Figure 3 This is the oil circuit diagram of the right servo valve in this invention.

[0038] Figure 4 This is a schematic diagram of the structure of the left and right hydraulic cylinders in this invention.

[0039] In the diagram: 1. Hydraulic oil tank; 2. Electric motor; 3. Main pump; 4. Control pump; 5. Relief valve; 6. Left servo valve; 7. Left first hydraulic check valve; 81. Left second hydraulic check valve; 82. Left first relief valve; 91. Left second relief valve; 92. Left first pressure sensor; 101. Left second pressure sensor; 102. Left hydraulic cylinder; 11. Base; 12. Base plate; 121. Column; 122. Upper synchronous beam; 13. Lower synchronous beam; 14. Limit block; 15. Stud; 16. Nut; 17. Bolt; 18. Right servo valve; 19. Right electromagnetic directional valve; 20. Right first hydraulic check valve; 211. Right second hydraulic check valve; 212. Right first relief valve; 221. Right second relief valve; 222. Right first pressure sensor; 231. Right second pressure sensor; 232. Right hydraulic cylinder; 24. Mounting lug; 25. Fixing plate; 26. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] See Figures 1 to 4 A hydraulic cylinder testing system includes a hydraulic oil tank 1, an electric motor 2, a main pump 3, a control pump 4, a left servo valve 6, a left hydraulic cylinder 11, a base 12, a limit block 15, a right servo valve 19, and a right hydraulic cylinder 24.

[0042] The hydraulic oil tank 1 is connected in sequence to the main pump 3 and the control pump 4;

[0043] The electric motor 2 is electrically connected to the main pump 3 and the control pump 4 respectively;

[0044] The oil outlet of the main pump 3 is connected to the P port of the left servo valve 6 via port P1. The A port of the left servo valve 6 is connected to the A port of the left hydraulic control check valve 81. The B port of the left hydraulic control check valve 81 is connected to the rodless chamber of the left hydraulic cylinder 11 via port A1.

[0045] The rod chamber of the left hydraulic cylinder 11 is connected to the B port of the left second hydraulic control check valve 82 via port B1. The oil outlet of the left second hydraulic control check valve 82 is connected to the B port of the left servo valve 6. The T port of the left servo valve 6 is connected to the hydraulic oil tank 1 via port T1.

[0046] The oil outlet of the main pump 3 is connected to the P port of the right servo valve 19 via port P1. The A port of the right servo valve 19 is connected to the A port of the right hydraulic control check valve 211. The B port of the right hydraulic control check valve 211 is connected to the rodless chamber of the right hydraulic cylinder 24 via port A1.

[0047] The rod chamber of the right hydraulic cylinder 24 is connected to the B port of the right second hydraulic control check valve 212 via port B1. The oil outlet of the right second hydraulic control check valve 212 is connected to the B port of the right servo valve 19. The T port of the right servo valve 19 is connected to the hydraulic oil tank 1 via port T1.

[0048] Multiple sets of limiting blocks 15 are installed on the top of the base 12, and a left hydraulic cylinder 11 and a right hydraulic cylinder 24 are arranged above the uppermost limiting block 15.

[0049] The cylinder barrels of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 are connected to the upper synchronous beam 13, and the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 pass through the lower synchronous beam 14 and are connected to the uppermost limiting block 15.

[0050] All the limiting blocks 15 are fixed to the base 12 by two sets of studs 17 and nuts 16, and the two sets of studs 17 and nuts 16 are symmetrically arranged at the left and right ends of the limiting blocks 15.

[0051] The top of the uppermost limiting block 15 is connected to two fixing plates 26 by bolts 18.

[0052] An overflow valve 5 is provided in the oil circuit between the control pump 4 and the left hydraulic cylinder 11, and in the oil circuit between the control pump 4 and the right hydraulic cylinder 24.

[0053] The X ports of the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 are connected to the A port of the left solenoid directional valve 7. The P port of the left solenoid directional valve 7 is connected to the control pump 4 via the R1 port. The T port of the left solenoid directional valve 7 is connected to the hydraulic oil tank 1 via the L1 port.

[0054] The Y ports of the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 are connected to the hydraulic oil tank 1 via port L1.

[0055] The first left hydraulic control check valve 81 is connected to the first left relief valve 91, and the second left hydraulic control check valve 82 is connected to the second left relief valve 92.

[0056] The first left hydraulic control check valve 81 is equipped with a first left pressure sensor 101, and the second left hydraulic control check valve 82 is equipped with a second left pressure sensor 102.

[0057] The X ports of the right first hydraulic control check valve 211 and the right second hydraulic control check valve 212 are connected to the A port of the right electromagnetic directional valve 20. The P port of the right electromagnetic directional valve 20 is connected to the control pump 4 via the R1 port. The T port of the right electromagnetic directional valve 20 is connected to the hydraulic oil tank 1 via the L1 port.

[0058] The Y ports of the right first hydraulic control check valve 211 and the right second hydraulic control check valve 212 are connected to the hydraulic oil tank 1 via port L1.

[0059] The right first hydraulic control check valve 211 is connected to the right first relief valve 221, and the right second hydraulic control check valve 212 is connected to the right second relief valve 222;

[0060] The right hydraulic control check valve 211 is equipped with a right pressure sensor 231, and the right hydraulic control check valve 212 is equipped with a right pressure sensor 232.

[0061] The length of the upper synchronous beam 13 is greater than the length of the lower synchronous beam 14.

[0062] The base 12 includes a base plate 121 and two columns 122. The top left and right ends of the base plate 121 are respectively connected to the bottom of the two columns 122, and the upper synchronous beam 13 is inserted into the upper end of the two columns 122.

[0063] The top of the base plate 121 is provided with multiple sets of limiting blocks 15. All the limiting blocks 15 are fixed to the base plate 121 by two sets of studs 17 and nuts 16. The two sets of studs 17 and nuts 16 are symmetrically arranged at the left and right ends of the limiting blocks 15.

[0064] Two sets of mounting lugs 25 are respectively installed on the cylinder barrels of the left hydraulic cylinder 11 and the right hydraulic cylinder 24, and all the mounting lugs 25 are arranged through the upper synchronous beam 13.

[0065] The piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 pass through the lower synchronous beam 14 and are respectively connected to the corresponding fixed plates 26.

[0066] The principle of this invention is explained as follows:

[0067] Hydraulic oil tank 1 is used to store hydraulic oil. Electric motor 2 is used to drive main pump 3 and control pump 4. The two pumps are a series pump. Main pump 3 is a constant pressure variable pump, which provides a stable high pressure oil source for the system. Control pump 4 is a fixed displacement pump, which stabilizes the output pressure through pump outlet relief valve 5 and provides pilot control oil to the left first hydraulic control check valve 81, left second hydraulic control check valve 82, right first hydraulic control check valve 211, and right second hydraulic control check valve 212. Left servo valve 6 is used to control left hydraulic cylinder 11. Right servo valve 19, right solenoid directional valve 20, right first hydraulic control check valve 211, right second hydraulic control check valve 212, right first relief valve 221, right second relief valve 222, right first pressure sensor 231, right second pressure sensor 232, and right hydraulic cylinder 24 are exactly the same as the corresponding components on the left.

[0068] Example 1:

[0069] A hydraulic cylinder testing system includes a hydraulic oil tank 1, an electric motor 2, a main pump 3, a control pump 4, a left servo valve 6, a left hydraulic cylinder 11, a base 12, a limit block 15, a right servo valve 19, and a right hydraulic cylinder 24. The hydraulic oil tank 1 is sequentially connected to the main pump 3 and the control pump 4. The electric motor 2 is electrically connected to both the main pump 3 and the control pump 4. The oil outlet of the main pump 3 is connected to the P port of the left servo valve 6 via port P1, and the A port of the left servo valve 6 is connected to the left hydraulic control valve 24. The A port of the left hydraulic check valve 81 is connected to the left hydraulic cylinder 11 via the A1 port, and the B port of the left hydraulic cylinder 11 is connected to the rodless chamber via the B1 port. The rod chamber of the left hydraulic cylinder 11 is connected to the B port of the left second hydraulic check valve 82 via the B1 port. The oil outlet of the left second hydraulic check valve 82 is connected to the B port of the left servo valve 6. The T port of the left servo valve 6 is connected to the hydraulic oil tank 1 via the T1 port. The oil outlet of the main pump 3 is connected to the P port of the right servo valve 19 via the P1 port. The A port of the right servo valve 19 is connected to the right first hydraulic check valve. Port A of 211 is connected; Port B of the right hydraulic check valve 211 is connected to the rodless chamber of the right hydraulic cylinder 24 via Port A1; the rod chamber of the right hydraulic cylinder 24 is connected to Port B of the right second hydraulic check valve 212 via Port B1; the oil outlet of the left second hydraulic check valve 82 is connected to Port B of the left servo valve 6; Port T of the left servo valve 6 is connected to the hydraulic oil tank 1 via Port T1; multiple sets of limit blocks 15 are installed on the top of the base 12, and the left hydraulic cylinder 11 is located above the uppermost limit block 15. Right hydraulic cylinder 24; the cylinder barrels of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 are connected to the upper synchronous beam 13, and the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 pass through the lower synchronous beam 14 and are connected to the uppermost limiting block 15; all the limiting blocks 15 are fixed to the base 12 by two sets of studs 17 and nuts 16, and the two sets of studs 17 and nuts 16 are symmetrically arranged at the left and right ends of the limiting blocks 15; the top of the uppermost limiting block 15 is connected to two fixing plates 26 by bolts 18.

[0070] When applying:

[0071] This design includes four test modes, which are illustrated using the left hydraulic cylinder as an example, as follows:

[0072] Test 1: Single-cylinder internal leakage test

[0073] 1. Leakage test of the rodless cavity of the left hydraulic cylinder

[0074] First, the left solenoid directional valve 7 is energized, controlling the oil outlet of pump 4 to open the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82. The left servo valve 6 controls the current to 0~10V and operates in the right position. The oil circuit function is P→A, B→T. The high-pressure oil from the main pump 3 outlet enters the rodless chamber of the left hydraulic cylinder 11 through the left servo valve 6 and the left first hydraulic control check valve 81. The oil in the rod chamber of the left hydraulic cylinder 11 returns through the left second hydraulic control check valve 82 and the left servo valve 6. Then, the piston rod is slowly extended. When the piston rod head contacts the limit block 15, it is held for about 5 seconds. Tighten the limit block 15 to eliminate its own deformation and corresponding piston rod displacement, preventing interference with the test. Record the value of the second left pressure sensor 102, which is approximately zero at this time. Then, continue to control the piston rod of the left hydraulic cylinder 11 to extend by the left servo valve 6. After holding for about 5 seconds, the left solenoid directional valve 7 is de-energized, which closes the first left hydraulic control check valve 81 and the second left hydraulic control check valve 82. At this time, the rodless chamber of the left hydraulic cylinder 11 can still receive oil, while the rod chamber is closed by the second left hydraulic control check valve 82. Hold for about 5 minutes and record the value of the second left pressure sensor 102 again.

[0075] If there is internal leakage in the left hydraulic cylinder 11, the high pressure oil will leak from the rodless chamber to the rod chamber. The pressure sensor 102 corresponding to the rod chamber, which is closed by the left second hydraulic control check valve 82, will rise, which means that the internal leakage in the rodless chamber is unqualified.

[0076] 2. Leakage test of the rod chamber of the left hydraulic cylinder

[0077] First, the left solenoid directional valve 7 is energized, controlling the oil outlet of pump 4 to open the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82. The left servo valve 6 controls the current from 0 to -10V, operating in the left position. The oil circuit function is P→B, A→T. The high-pressure oil from the main pump 3 outlet enters the rod chamber of the left hydraulic cylinder 11 through the left servo valve 6 and the left second hydraulic control check valve 82. The oil in the rodless chamber of the left hydraulic cylinder 11 returns through the left first hydraulic control check valve 81 and the left servo valve 6. Then, the piston rod is slowly retracted, and after tightening the stud 17, it is held for about 5 seconds. s, eliminate the piston rod displacement corresponding to its own deformation to prevent interference with the test, record the value of the left pressure sensor 101, which is about zero at this time; then continue to make the left servo valve control the piston rod of the left hydraulic cylinder to retract, hold for about 5s, then the left solenoid directional valve 7 is de-energized, that is, the left hydraulic control check valve 81 and the left hydraulic control check valve 82 are closed. At this time, the rod chamber of the left hydraulic cylinder 11 can still be filled with oil, while the rodless chamber is closed by the left hydraulic control check valve 81. Hold for about 5min, and record the value of the left pressure sensor 101 again at this time;

[0078] If there is internal leakage in the left hydraulic cylinder 11, the high pressure oil will leak from the rod chamber to the rodless chamber. The pressure sensor 101 corresponding to the rodless chamber, which is closed by the left hydraulic check valve 81, will rise, which means that the internal leakage in the rod chamber is unqualified.

[0079] Experiment 2: Single-cylinder control accuracy test

[0080] First, remove the limit block 15, stud 16, nut 17, and bolt 18, without installing the synchronization beam 14, so that the piston rod of the left hydraulic cylinder 11 is in a free state; then, the left solenoid directional valve 7 is energized, controlling the outlet oil of pump 4 to open the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82; at this time, the left servo valve 6 controls the piston rod of the left hydraulic cylinder 11 to extend or retract, and the control accuracy is detected by the displacement sensor built into the left hydraulic cylinder 11. If it is better than the position synchronization accuracy required by the product, such as 0.1mm, then proceed to test three; if it is lower than the position synchronization accuracy required by the product, then readjustment is required.

[0081] Experiment 3: Dual-cylinder synchronous test—without lower synchronous beam

[0082] First, remove the limit block 15, stud 16, nut 17, and bolt 18, without installing the synchronization beam 14, so that the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 are in a free state. Then, energize the left solenoid directional valve 7 and the right solenoid directional valve 20 to control the oil outlet of pump 4 to open the left first hydraulic control check valve 81, the left second hydraulic control check valve 82, the right first hydraulic control check valve 211, and the right second hydraulic control check valve 212. At this time, the left servo valve 6 and the right servo valve 19 simultaneously control the extension or retraction of the hydraulic cylinder piston rods, and the control accuracy is detected by the displacement sensor built into the hydraulic cylinder. Then, compare the displacement difference between the left hydraulic cylinder 11 and the right hydraulic cylinder 24. If it is better than the position synchronization accuracy required by the product, such as 0.1mm, then proceed to test four. If it is lower than the position synchronization accuracy required by the product, then readjustment is required.

[0083] Test 4: Dual-cylinder synchronous test – with lower synchronous beam

[0084] First, install the synchronous beam 14 to simulate the actual working conditions of the product; then, energize both the left solenoid directional valve 7 and the right solenoid directional valve 20, controlling the oil outlet of pump 4 to open the left first hydraulic control check valve 81, the left second hydraulic control check valve 82, the right first hydraulic control check valve 211, and the right second hydraulic control check valve 212; at this time, the left servo valve 6 and the right servo valve 19 simultaneously control the extension or retraction of the hydraulic cylinder piston rod, and detect the control accuracy through the displacement sensor built into the hydraulic cylinder, while simultaneously detecting the values ​​of the left and right pressure sensors; then compare the values ​​of the left hydraulic cylinder 11 and the right hydraulic cylinder. If the displacement difference of cylinder 24, and the pressure difference of the left pressure sensor 101, the second left pressure sensor 102, the first right pressure sensor 231, and the second right pressure sensor 232 are better than the product's required position synchronization accuracy (e.g., 0.1 mm) and pressure difference threshold (e.g., 2 MPa), then the test is qualified. Conversely, if the synchronization accuracy is poor, it will cause the left hydraulic cylinder 11 and the right hydraulic cylinder 24 to affect each other, resulting in the pressure difference exceeding the threshold. In this case, the test is unqualified, and the control program needs to be further debugged. Then, the above steps are repeated until the test is qualified.

[0085] Example 2:

[0086] Example 2 is basically the same as Example 1, except that:

[0087] A hydraulic cylinder testing system includes a left hydraulic control check valve 81 and a left hydraulic control check valve 82, whose X ports are connected to the A port of a left solenoid directional valve 7. The P port of the left solenoid directional valve 7 is connected to a control pump 4 via an R1 port, and the T port of the left solenoid directional valve 7 is connected to a hydraulic oil tank 1 via an L1 port. The Y ports of the left hydraulic control check valve 81 and the left hydraulic control check valve 82 are connected to the hydraulic oil tank 1 via an L1 port. The left hydraulic control check valve 81 is connected to a left relief valve 91, and the left hydraulic control check valve 82 is connected to a left relief valve 92. A left pressure sensor 101 is installed on the left hydraulic control check valve 81, and a left pressure sensor 102 is installed on the left hydraulic control check valve 82. The X ports of the right first hydraulic control check valve 211 and the right second hydraulic control check valve 212 are connected to the A port of the right solenoid directional valve 20. The P port of the right solenoid directional valve 20 is connected to the control pump 4 via the R1 port, and the T port of the right solenoid directional valve 20 is connected to the hydraulic oil tank 1 via the L1 port. The Y ports of the right first hydraulic control check valve 211 and the right second hydraulic control check valve 212 are connected to the hydraulic oil tank 1 via the L1 port. The right first hydraulic control check valve 211 is connected to the right first relief valve 221, and the right second hydraulic control check valve 212 is connected to the right second relief valve 222. The right first hydraulic control check valve 211 is equipped with a right first pressure sensor 231, and the right second hydraulic control check valve 212 is equipped with a right second pressure sensor 232.

[0088] In application: To ensure control accuracy, the left servo valve 6 has a built-in valve core position feedback closed loop. When the control current is 0~10V, the left servo valve operates in the right position, with the hydraulic circuit function being P→A, B→T, corresponding to the extension of the piston rod of the left hydraulic cylinder 11; when the control current is 0~-10V, the left servo valve 6 operates in the left position, with the hydraulic circuit function being P→B, A→T, corresponding to the retraction of the piston rod of the left hydraulic cylinder 11. The left solenoid directional valve 7 is used to control the on / off state of the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82. When the left solenoid directional valve 7 is de-energized, the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 are closed, locking the left hydraulic cylinder 11; when .... When energized, the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 open, allowing the piston rod of the left hydraulic cylinder 11 to extend and retract freely. The left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 are used to control whether the left hydraulic cylinder 11 is working. Both the left first hydraulic control check valve 81 and the left second hydraulic control check valve 82 are controlled by a left solenoid directional valve to ensure synchronous opening or closing. The left first relief valve 91 and the left second relief valve 92 are used to protect the left hydraulic cylinder 11 and prevent overpressure. The left first pressure sensor 101 and the left second pressure sensor 102 are used to detect the pressure in the rodless chamber and the rod chamber of the left hydraulic cylinder 11. The left hydraulic cylinder 11 has a built-in displacement sensor to detect the displacement of the piston and piston rod.

[0089] Example 3:

[0090] Example 3 is basically the same as Example 1, except that:

[0091] A hydraulic cylinder testing system is provided, wherein the length of the upper synchronous beam 13 is greater than the length of the lower synchronous beam 14; the base 12 includes a base plate 121 and two columns 122, the left and right ends of the top of the base plate 121 are respectively connected to the bottom of the two columns 122, and the upper synchronous beam 13 is inserted into the upper end of the two columns 122; the top of the base plate 121 is provided with multiple sets of limiting blocks 15, all of which are fixed to the base plate 121 by two sets of studs 17 and nuts 16, which are symmetrically arranged at the left and right ends of the limiting blocks 15; the cylinder barrels of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 are respectively equipped with two sets of mounting lugs 25, all of which are arranged through the upper synchronous beam 13; the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 pass through the lower synchronous beam 14 and are respectively connected to the corresponding fixing plates 26.

[0092] In application: the base plate 121 supports the limiting block 15; the column 122 is used to fix the upper synchronous beam 13, which is used to install and fix the cylinders of the left hydraulic cylinder 11 and the right hydraulic cylinder 24; the height is adjusted by adjusting the number or thickness of the limiting blocks 15 to correspond to different positions of the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24, and the extension and retraction of the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 are controlled by the left servo valve 6 and the right servo valve 19, so that the internal leakage test at the intermediate position can be performed; the lower synchronous beam 14 is used to mechanically synchronize the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 to test the synchronization control accuracy of the left hydraulic cylinder 11 and the right hydraulic cylinder 24; the studs 16 and nuts 17 are used to fix the limiting block 15, and the limiting block height 15 is locked with nuts 17 after adjustment; the bolts 18 are used to connect and fix the piston rods of the left hydraulic cylinder 11 and the right hydraulic cylinder 24 and the weight.

[0093] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A hydraulic cylinder testing system, characterized in that: The hydraulic cylinder test system includes a hydraulic oil tank (1), an electric motor (2), a main pump (3), a control pump (4), a left servo valve (6), a left hydraulic cylinder (11), a base (12), a limit block (15), a right servo valve (19), and a right hydraulic cylinder (24). The hydraulic oil tank (1) is connected in sequence to the main pump (3) and the control pump (4); The electric motor (2) is electrically connected to the main pump (3) and the control pump (4) respectively; The oil outlet of the main pump (3) is connected to the P port of the left servo valve (6) via the P1 port. The A port of the left servo valve (6) is connected to the A port of the left hydraulic control check valve (81). The B port of the left hydraulic control check valve (81) is connected to the rodless chamber of the left hydraulic cylinder (11) via the A1 port. The rod chamber of the left hydraulic cylinder (11) is connected to the B port of the left second hydraulic control check valve (82) via port B1. The oil outlet of the left second hydraulic control check valve (82) is connected to the B port of the left servo valve (6). The T port of the left servo valve (6) is connected to the hydraulic oil tank (1) via port T1. The oil outlet of the main pump (3) is connected to the P port of the right servo valve (19) via the P1 port. The A port of the right servo valve (19) is connected to the A port of the right hydraulic control check valve (211). The B port of the right hydraulic control check valve (211) is connected to the rodless chamber of the right hydraulic cylinder (24) via the A1 port. The rod chamber of the right hydraulic cylinder (24) is connected to the B port of the right second hydraulic control check valve (212) via port B1. The oil outlet of the right second hydraulic control check valve (212) is connected to the B port of the right servo valve (19). The T port of the right servo valve (19) is connected to the hydraulic oil tank (1) via port T1. The base (12) has multiple sets of limiting blocks (15) installed on its top, and a left hydraulic cylinder (11) and a right hydraulic cylinder (24) are provided above the uppermost limiting block (15). The cylinder barrels of the left hydraulic cylinder (11) and the right hydraulic cylinder (24) are connected to the upper synchronous beam (13), and the piston rods of the left hydraulic cylinder (11) and the right hydraulic cylinder (24) pass through the lower synchronous beam (14) and are connected to the uppermost limiting block (15). All the limiting blocks (15) are fixed to the base (12) by two sets of studs (17) and nuts (16), and the two sets of studs (17) and nuts (16) are symmetrically arranged at the left and right ends of the limiting blocks (15); The top of the uppermost limiting block (15) is connected to two fixing plates (26) by bolts (18).

2. The hydraulic cylinder testing system according to claim 1, characterized in that: An overflow valve (5) is provided in the oil circuit between the control pump (4) and the left hydraulic cylinder (11), and in the oil circuit between the control pump (4) and the right hydraulic cylinder (24).

3. The hydraulic cylinder testing system according to claim 1, characterized in that: The X port of the left first hydraulic control check valve (81) and the left second hydraulic control check valve (82) are connected to the A port of the left electromagnetic directional valve (7). The P port of the left electromagnetic directional valve (7) is connected to the control pump (4) via the R1 port. The T port of the left electromagnetic directional valve (7) is connected to the hydraulic oil tank (1) via the L1 port. The Y ports of the left first hydraulic control check valve (81) and the left second hydraulic control check valve (82) are connected to the hydraulic oil tank (1) via the L1 port.

4. The hydraulic cylinder testing system according to claim 3, characterized in that: The first left hydraulic control check valve (81) is connected to the first left relief valve (91), and the second left hydraulic control check valve (82) is connected to the second left relief valve (92). The first left hydraulic check valve (81) is equipped with a first left pressure sensor (101), and the second left hydraulic check valve (82) is equipped with a second left pressure sensor (102).

5. A hydraulic cylinder testing system according to claim 4, characterized in that: The X port of the right first hydraulic control check valve (211) and the right second hydraulic control check valve (212) are connected to the A port of the right electromagnetic directional valve (20). The P port of the right electromagnetic directional valve (20) is connected to the control pump (4) via the R1 port. The T port of the right electromagnetic directional valve (20) is connected to the hydraulic oil tank (1) via the L1 port. The Y ports of the right first hydraulic control check valve (211) and the right second hydraulic control check valve (212) are connected to the hydraulic oil tank (1) via the L1 port.

6. A hydraulic cylinder testing system according to claim 5, characterized in that: The right first hydraulic control check valve (211) is connected to the right first relief valve (221), and the right second hydraulic control check valve (212) is connected to the right second relief valve (222); The right hydraulic control check valve (211) is equipped with a right pressure sensor (231), and the right hydraulic control check valve (212) is equipped with a right pressure sensor (232).

7. A hydraulic cylinder testing system according to claim 1, characterized in that: The length of the upper synchronous beam (13) is greater than the length of the lower synchronous beam (14).

8. A hydraulic cylinder testing system according to claim 7, characterized in that: The base (12) includes a base plate (121) and two columns (122). The top left and right ends of the base plate (121) are connected to the bottom of the two columns (122) respectively, and the upper synchronous beam (13) is inserted into the upper end of the two columns (122). The top of the base plate (121) is provided with multiple sets of limiting blocks (15). All the limiting blocks (15) are fixed to the base plate (121) by two sets of studs (17) and nuts (16). The two sets of studs (17) and nuts (16) are symmetrically arranged at the left and right ends of the limiting blocks (15).

9. A hydraulic cylinder testing system according to claim 8, characterized in that: The left hydraulic cylinder (11) and the right hydraulic cylinder (24) are respectively equipped with two sets of mounting columns (25), and all the mounting columns (25) are installed through the upper synchronous beam (13).

10. A hydraulic cylinder testing system according to claim 9, characterized in that: The piston rods of the left hydraulic cylinder (11) and the right hydraulic cylinder (24) pass through the lower synchronous beam (14) and are connected to the corresponding fixed plates (26) respectively.

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