Rotary joint hydraulic test system and control method

Abstract

The application discloses a kind of rotary joint hydraulic test system and control method, the control method is connected by hydraulic test system first hydraulic joint and second hydraulic joint on test piece, and supplies hydraulic high pressure and hydraulic low pressure to two respectively, then by hydraulic drive system low-speed drive first hydraulic joint and second hydraulic joint rotate to one end value of rated angle range, maintain the pressure value and then pressure relief to zero, then alternate the supplied hydraulic value of first hydraulic joint and second hydraulic joint, and drive first hydraulic joint and second hydraulic joint rotate to another end value of rated angle range, complete hydraulic test cycle is formed once, by multiple cycles, it is helpful to optimize the sealing selection of rotary joint, improve its reliability.

Description

Technical Field

[0001] This invention relates to the field of performance testing technology for aircraft landing gear rotary joints, and more specifically, to a rotary joint hydraulic testing system and control method. Background Technology

[0002] The rotary joint accessory on the aircraft landing gear strut actuator needs to undergo durability testing during the design and evaluation process to assess the sealing and wear resistance of the rotary joint, so as to optimize the sealing selection of the rotary joint based on the test results.

[0003] Chinese patent application CN115326621A discloses a wear testing fixture for a hydraulic strut rotary joint. The fixture includes a frame, a drive unit mounted on the frame, a main shaft, a fixed clamp assembly, and a swing clamp assembly. The output end of the drive unit is connected to one end of the main shaft to drive it to rotate forward and backward. The other end of the main shaft is connected to the swing clamp assembly, on which the rotating shaft of the hydraulic strut rotary joint is fixedly connected. The rotating shaft, fixed to the fixed clamp assembly, is coaxial with the main shaft. This invention enables wear testing of the sealing ring in a hydraulic strut rotary joint, allowing for the study of the seal's wear under different environments, swing angles, and swing cycles. The aforementioned hydraulic strut rotary joint wear test fixture provides a detailed description of the connection methods and movement modes of its drive unit, main shaft, and other components. It represents a significant achievement in theoretical research and practical exploration in the field of rotary joint test bench design. However, its application is specific to certain products and has the following limitations: Firstly, it does not provide the principle and composition of the hydraulic system for the rotary joint test bench; it only proposes the mechanical design scheme of the test fixture. The rotary joint test system should also include a hydraulic system and an electrical system, with the test fixture being only one part. The detailed composition and implementation principle of the hydraulic system cannot be determined from the scheme. Secondly, due to these limitations, the patent application does not provide a test method for the rotary joint, does not disclose whether the rotary joint needs to be connected to the hydraulic system, and does not specify the requirements for the logical functions of the hydraulic control. Summary of the Invention

[0004] To address the above-mentioned deficiencies or improvement needs of existing technologies, this invention provides a rotary joint hydraulic testing system and method, which enables the rotary joint on the aircraft landing gear strut actuator cylinder to be rotated for testing.

[0005] To achieve the above objectives, according to one aspect of the present invention, a hydraulic testing system for a rotary joint is provided, including a P port for supplying oil to a test bench. The oil circuit at the P port is divided into a first oil circuit and a second oil circuit. The hydraulic testing system further includes a hydraulic drive system connected to the first oil circuit and a hydraulic testing system connected to the second oil circuit. The hydraulic drive system includes a second pressure reducing valve, a proportional directional valve, a shuttle valve, a shut-off valve, a one-way speed regulating valve, a swing hydraulic cylinder having chambers C and D, and a second oil tank. The first oil circuit is sequentially connected to the second pressure reducing valve and the proportional directional valve. Two branches are arranged downstream of the proportional directional valve; one branch connects to chamber D of the swing hydraulic cylinder, and the other branch sequentially connects to the one-way speed regulating valve and chamber C of the swing hydraulic cylinder. The shuttle valve and the shut-off valve are arranged in parallel between the two branches. When the shut-off valve is closed, the swing hydraulic cylinder is in a pressurized driven state; when the shut-off valve is open, the swing hydraulic cylinder is in a depressurized and stationary state. A push-pull mechanism is provided inside the swing hydraulic cylinder for driving the swing hydraulic cylinder to rotate around a main shaft. The proportional directional valve is connected upstream of the second oil tank. The inlet of the directional control valve is connected to the second pressure reducing valve, and the outlet of the proportional directional control valve is connected to the shuttle valve. The hydraulic testing system includes a second oil circuit, and a pressure control pipeline and a directional control pipeline connected in parallel downstream of the second oil circuit. The hydraulic testing system includes a first pressure reducing valve, a first oil tank, a first solenoid directional control valve, a second solenoid directional control valve, a third solenoid directional control valve, a fourth solenoid directional control valve, a first check valve, a second check valve, a first reversing circuit, and a second reversing circuit. The pressure control pipeline is connected to the first pressure reducing valve, and the first check valve... The first pressure reducing valve and the second check valve are connected in parallel downstream of the first pressure reducing valve. The first reversing circuit and the second reversing circuit are connected in parallel downstream of the directional control pipeline. The first reversing circuit is connected in series with the first solenoid reversing valve and the third solenoid reversing valve. The second reversing circuit is connected in series with the second solenoid reversing valve and the fourth solenoid reversing valve. The downstream pipeline of the first reversing circuit is connected to the first hydraulic joint with a rod chamber. The downstream pipeline of the second reversing circuit is connected to the second hydraulic joint without a rod chamber. Both the first solenoid reversing valve and the second solenoid reversing valve are connected to the first oil tank.

[0006] Furthermore, a first pressure sensor is installed on the pipeline leading to the first hydraulic connector, and a second pressure sensor is installed on the pipeline leading to the second hydraulic connector.

[0007] According to another aspect of the present invention, a control method for a rotary joint hydraulic testing system is provided, comprising the following steps: The first step is to connect the first hydraulic connector on the test piece to the downstream pipeline of the first reversing circuit, and connect the second hydraulic connector to the downstream pipeline of the second reversing circuit, and depressurize the first and second hydraulic connectors. The second step involves pressurizing the first hydraulic connector to the first pressure and the second hydraulic connector to the second pressure. The push-pull mechanism drives the main shaft of the swing hydraulic cylinder to rotate clockwise to reach the rated angle. The third step is to depressurize the first and second hydraulic connectors; Fourth step: the first hydraulic connector is pressurized to the second pressure, the second hydraulic connector is pressurized to the first pressure, and the push-pull mechanism drives the swing hydraulic cylinder to rotate counterclockwise around the main shaft to reach the rated rotation angle; Fifth step: depressurize the first hydraulic connector and the second hydraulic connector, disconnect the first hydraulic connector from the downstream pipeline of the first reversing circuit, disconnect the second hydraulic connector from the downstream pipeline of the second reversing circuit, and complete the durability test of the first hydraulic connector and the second hydraulic connector.

[0008] Furthermore, in the second step, the one-way speed control valve of the hydraulic drive system circuit throttles and regulates the speed on the return oil circuit. The one-way speed control valve cooperates with the proportional directional valve. By setting the valve opening of both valves, different angular velocities are achieved for the forward or reverse rotation of the hydraulic swing cylinder, so that the push-pull mechanism in the second step drives the swing hydraulic cylinder spindle to achieve a low-speed drive of 6s to 7s.

[0009] Furthermore, in the second step, the second pressure reducing valve and the shuttle valve are respectively connected to the oil inlet end and the oil outlet end of the proportional directional valve, forming a constant pressure difference ΔP between the oil inlet end and the oil outlet end of the proportional directional valve, thereby maintaining a constant flow rate when the load changes and improving the speed rigidity of the swing hydraulic cylinder.

[0010] Furthermore, in the fourth step, the one-way speed control valve is in a one-way open state and does not participate in speed regulation.

[0011] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) The present invention provides a control method for a rotary joint hydraulic test system. By setting a pressure compensation unit, the rotary drive is smooth and stable, the forward / reverse rotation speed is adjustable, and the dual joint alternating supply / release function and high / low pressure on / off function are well integrated and highly accurate.

[0012] (2) The present invention provides a hydraulic test system for rotary joints. The test bench is used to assess the sealing performance and wear resistance of the test piece, which helps to optimize the sealing selection of hydraulic rotary joints and improve their reliability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the hydraulic testing system for the rotary joint according to an embodiment of the present invention; Figure 2 This is a control logic diagram of the rotary joint hydraulic valve according to an embodiment of the present invention.

[0014] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. First hydraulic joint; 2. Second hydraulic joint; 3. First oil circuit; 4. Second oil circuit; 5. Pressure control pipeline; 11. First solenoid directional valve; 12. Second solenoid directional valve; 21. Third solenoid directional valve; 22. Fourth solenoid directional valve; 31. First check valve; 32. Second check valve; 41. First pressure sensor; 42. Second pressure sensor; 51. First pressure reducing valve; 52. Second pressure reducing valve; 61. First oil tank; 62. Second oil tank; 7. Proportional directional valve; 8. Shuttle valve; 9. Shut-off valve; 10. One-way speed control valve; 13. Swing hydraulic cylinder. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0016] like Figure 1 As shown, according to the first aspect of the present invention, this embodiment provides a rotary joint hydraulic testing system. The test bench includes a hydraulic drive system and a hydraulic drive system. The test piece is an aircraft landing gear strut actuator cylinder. The strut actuator cylinder includes a first hydraulic joint 1 with a rod cavity and a second hydraulic joint 2 without a rod cavity. Both the first hydraulic joint 1 and the second hydraulic joint 2 are connected to hydraulic hoses. The connection points are rotatable structures. During the forward / reverse rotation of the first hydraulic joint 1 and the second hydraulic joint 2 of the test object, the two are alternately pressurized / depressurized to achieve the durability test function.

[0017] like Figure 1 As shown, the entire test bench is connected to pressurized oil through the hydraulic inlet at point P, and the oil circuits branch off from point P into three lines, each leading to... Figure 1 To the left, up, and right of point P, the first oil circuit 3, located on the right side of the diagram, connects to the hydraulic drive system, and the second oil circuit 4 connects to the hydraulic testing system. Downstream of the second oil circuit 4, it splits into a pressure control line 5 and a direction control line 4, both connected in parallel. The pressure control line 5 is located... Figure 1At point P, facing upwards, the direction control pipeline is located to the left of point P. The hydraulic drive system is used to control the swing hydraulic cylinder 13. The hydraulic drive system includes a second pressure reducing valve 52, a proportional directional valve 7, a shuttle valve 8, a shut-off valve 9, a one-way speed regulating valve 10, the swing hydraulic cylinder 13 with chambers C and D, and a second oil tank 62. The first oil circuit 3 is sequentially connected to the second pressure reducing valve 52 and the proportional directional valve 7. Two branches are provided downstream of the proportional directional valve 7; one branch connects to chamber D of the swing hydraulic cylinder 13, and the other... A branch line connects sequentially to the C chamber of the one-way speed regulating valve 10 and the swing hydraulic cylinder 13. The shuttle valve 8 and the shut-off valve 9 are connected in parallel between the two branches. The upstream of the proportional directional valve 7 is connected to the second oil tank 62. The pressure reducing valve 52 reduces the hydraulic inlet pressure P to the rated low pressure P2. The pressure reducing valve 52 and the shuttle valve 8 form a pressure compensation unit, creating a constant pressure difference ΔP between the oil inlet and working port of the proportional directional valve 7, thereby maintaining a constant flow of pressure oil when the load changes and improving the speed rigidity of the swing hydraulic cylinder 13. Furthermore, the shut-off valve 9 is used to select between two states: pressure-driven or pressureless. When the shut-off valve 9 is closed, the swing hydraulic cylinder 11 is in a pressure-driven state; when the shut-off valve 9 is open, the swing hydraulic cylinder 11 is in a pressureless state.

[0018] Furthermore, in the appendix Figure 1 The swing hydraulic cylinder 11 shown has a one-way speed control valve 10 installed in chamber C, which works in conjunction with the proportional directional valve 7. By setting the valve openings of both the proportional directional valve 7 and the one-way speed control valve 10, the swing hydraulic cylinder 11 can achieve different angular velocities for forward and reverse rotation.

[0019] Furthermore, located in Figure 1The second oil circuit 4 on the left side of the hydraulic inlet P is connected to the hydraulic test system. Downstream of the second oil circuit 4, a pressure control line 5 and a directional control line are connected in parallel. The hydraulic test system includes a first pressure reducing valve 51, a first oil tank (61), a first solenoid directional valve 11, a second solenoid directional valve 12, a third solenoid directional valve 21, a fourth solenoid directional valve 22, a first check valve 31, a second check valve 32, a first reversing circuit, and a second reversing circuit. The hydraulic test system is used to control the pressure and direction during the test. Specifically, after the P port is connected to the inlet pressure P of the hydraulic system pump station, it enters the hydraulic test system from the left side. The second oil circuit 4 is then divided into two lines, namely the pressure control line 5 and the directional control line. The pressure control line 5 enters the first pressure reducing valve 51, and then downstream it is connected to two parallel first check valves 31 and second check valves 32 to reduce the inlet pressure P to the pressure required by the first hydraulic connector 1 and the second hydraulic connector 2. In this embodiment, the pressure is 1 MPa. Downstream of the directional control pipeline is connected to two sets of parallel first and second reversing circuits. The first reversing circuit is connected in series with a first solenoid directional valve 11 and a third solenoid directional valve 21, both of which are two-position three-way valves. The second reversing circuit is connected in series with a second solenoid directional valve 12 and a fourth solenoid directional valve 22, both of which are normally open two-position two-way valves. Downstream of the first reversing circuit is the first hydraulic connector 1, and downstream of the second reversing circuit is the second hydraulic connector 2. Further, a first pressure sensor 41 is installed on the pipeline entering the first hydraulic connector 1 to measure the hydraulic pressure of the first hydraulic connector 1, and a second pressure sensor 42 is installed on the pipeline entering the second hydraulic connector 2 to measure the hydraulic pressure of the second hydraulic connector 2. Figure 1 As shown, the hydraulic testing system and the hydraulic drive system are each equipped with an oil tank.

[0020] Furthermore, the test bench in the embodiment is used to conduct a durability test on the aircraft landing gear strut actuator, including several single cycles, each single cycle including the following two steps: Step 1: Supply the second pressure to the first hydraulic connector 1 and the first pressure to the second hydraulic connector 2. In this embodiment, the second pressure is 21 MPa and the first pressure is 1 MPa. The main shaft of the swing hydraulic cylinder 13 rotates the support rod actuator cylinder forward by +α°, which is +45° in this embodiment, for 6 to 7 seconds. Maintain the hydraulic pressure of the first hydraulic connector 1 and the second hydraulic connector 2 for 3 seconds, and then release the pressure to zero. Step 2: The first hydraulic connector 1 supplies the first pressure and the second hydraulic connector 2 supplies the second pressure. The external force causes the cylinder to rotate in the opposite direction by -α°, which is -45° in this embodiment, to enter the initial state. This takes 4 to 5 seconds. The first hydraulic connector 1 and the second hydraulic connector 2 maintain the hydraulic pressure for 3 seconds, and then the pressure is released to zero.

[0021] Furthermore, to complete the above-mentioned single-cycle action using a test bench, the present invention provides a control method for a rotary joint hydraulic test system, comprising the following steps: Step 1: Connect the first hydraulic connector on the test piece to the downstream pipeline of the first reversing circuit, and connect the second hydraulic connector to the downstream pipeline of the second reversing circuit. Depressurize the first hydraulic connector 1 and the second hydraulic connector 2. In the hydraulic drive system, the solenoids DT5 and DT6 in the proportional reversing valve 7 are de-energized, the valve core is in the neutral O-type function, and the oil circuit is closed. In the hydraulic test system, the solenoids DT1, DT2, DT3, and DT4 in the first solenoid reversing valve 11, the second solenoid reversing valve 12, the third solenoid reversing valve 21, and the fourth solenoid reversing valve 22 are de-energized, the valve cores are in the normal function, and the oil circuit is open. The pressurized oil is divided into two paths after passing through the first pressure reducing valve 51. One path passes through the first check valve 31, the fourth solenoid reversing valve 22, the second solenoid reversing valve 12, and enters the first oil tank 61. The other path passes through the second check valve 32, the third solenoid reversing valve 21, the first solenoid reversing valve 11, and enters the first oil tank 61.

[0022] Step 2: The first hydraulic connector 1 is pressurized to 21MPa, and the second hydraulic connector 2 is pressurized to 1MPa. In the hydraulic drive system, the electromagnet DT5 in the proportional directional valve 7 is energized, causing the valve core to open to the left. The pressure oil passes through the second pressure reducing valve 52, the proportional directional valve 7, and enters the D chamber of the swing hydraulic cylinder 13. The swing hydraulic cylinder 13 is equipped with a push-pull mechanism. The push-pull mechanism drives the main shaft of the swing hydraulic cylinder 13 to rotate clockwise through gear transmission, reaching the rated rotation angle +45°. The pressure oil in the C chamber of the swing hydraulic cylinder 13 enters the proportional directional valve 7 through the one-way speed regulating valve 10 and finally enters the second oil tank 62. Furthermore, in the second step, the one-way speed control valve 10 of the hydraulic drive system circuit throttles and regulates the speed on the return oil line, so that the swing hydraulic cylinder 13 obtains a lower speed to achieve... Figure 2The table shows that the second step requires a lower drive speed of 6 to 7 seconds. The second pressure reducing valve 52 and the shuttle valve 8 are connected to the inlet and outlet of the proportional directional valve 7, respectively, forming a constant pressure difference ΔP between the inlet and outlet of the proportional directional valve 7. This maintains a constant flow rate when the load changes, improving the speed rigidity of the swing hydraulic cylinder 13. In the hydraulic test system, the pressure oil is divided into a pressure control line 5 and a direction control line. The direction control line passes through the first solenoid directional valve 11, the third solenoid directional valve 21, and the first hydraulic connector 1. The system provides 21MPa hydraulic pressure. During this process, the solenoid DT1 of the first solenoid directional valve 11 is energized and opens to the left, while the solenoid DT3 of the third solenoid directional valve 21 is de-energized and opens to the right. The pressure control pipeline 5 provides 1MPa hydraulic pressure through the first pressure reducing valve 51, the first check valve 31, and the rotating second hydraulic connector 2. During this process, the second check valve 32 is closed, the solenoid DT4 in the fourth solenoid directional valve 22 is energized and operates to the left, and the oil circuit is closed, isolating the high and low pressures between the first hydraulic connector 1 and the second hydraulic connector 2.

[0023] Furthermore, during the clockwise rotation of the first hydraulic connector 1 and the second hydraulic connector 2, and during the process of stopping and maintaining pressure at the rated rotation angle, both the hydraulic drive system and the hydraulic test system maintain the aforementioned control logic state.

[0024] Step 3: Depressurize the first hydraulic connector 1 and the second hydraulic connector 2. The control logic of the hydraulic drive system and the hydraulic test system is the same as in the first step, so as to realize the depressurization of the first hydraulic connector 1 and the second hydraulic connector 2.

[0025] Step 4: The first hydraulic connector 1 is pressurized to 1 MPa, and the second hydraulic connector 2 is pressurized to 21 MPa. In the hydraulic drive system, the solenoid DT6 inside the proportional directional valve 7 is energized, opening the valve core to the right. Pressurized oil passes through the second pressure reducing valve 52, the proportional directional valve 7, and the one-way speed regulating valve 10, entering chamber C of the swing hydraulic cylinder 13. Through the push-pull mechanism, the main shaft of the swing hydraulic cylinder 13 rotates counterclockwise to reach the rated angle of -45°. The oil in chamber D of the swing hydraulic cylinder 13 flows through the proportional directional valve 7 to the second oil tank 62. In this circuit, the one-way speed regulating valve 10 is open in one direction on the inlet line without speed regulation, allowing the swing hydraulic cylinder 13 to achieve a faster speed. Figure 1 The second step in the table requires a drive speed of 4 to 5 seconds.

[0026] Furthermore, the hydraulic oil in the hydraulic testing system is divided into two paths. One path passes through the second solenoid directional valve 12, where the solenoid DT2 is energized and opens to the left, then passes through the fourth solenoid directional valve 22, where the solenoid DT4 is de-energized and opens to the right, and finally enters the second hydraulic connector 2, providing a hydraulic pressure of 21 MPa. The other path of hydraulic oil passes through the first pressure reducing valve 51, the second check valve 32, and the first hydraulic connector 1, providing a hydraulic pressure of 1 MPa. During the counterclockwise rotation of the first hydraulic connector 1 and the second hydraulic connector 2, and during the rotation to the rated angle and the pressure holding process, the function of each component and the control logic state are the same as in the second step.

[0027] Finally, in the fifth step, the first hydraulic connector 1 and the second hydraulic connector 2 are depressurized. The control logic of the hydraulic drive system and the hydraulic test system is the same as in the first step. The connection between the first hydraulic connector 1 and the downstream pipeline of the first reversing circuit is disconnected, and the connection between the second hydraulic connector 2 and the downstream pipeline of the second reversing circuit is disconnected, thus completing the durability test. Through the hydraulic control logic of the first to fourth steps mentioned above, the first hydraulic connector 1 and the second hydraulic connector 2 complete a complete single hydraulic test cycle. Through multiple single hydraulic test cycles, the durability test of the first hydraulic connector 1 and the second hydraulic connector 2 is completed.

[0028] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotary union hydrostatic test system comprising a P port for supplying oil to the test system, the oil path at the P port being split into a first oil path (3) and a second oil path (4), characterised in that, The hydraulic testing system also includes a hydraulic drive system connected to the first oil circuit (3), a hydraulic testing device connected to the second oil circuit (4), and a pressure control pipeline (5) and a direction control pipeline connected in parallel downstream of the second oil circuit (4); The hydraulic drive system includes a second pressure reducing valve (52), a proportional directional valve (7), a shuttle valve (8), a shut-off valve (9), a one-way speed control valve (10), a swing hydraulic cylinder (13) with chambers C and D, and a second oil tank (62). The first oil circuit (3) is sequentially connected to the second pressure reducing valve (52) and the proportional directional valve (7). Two branches are arranged downstream of the proportional directional valve (7). One branch connects to the D chamber of the swing hydraulic cylinder (13), and the other branch connects sequentially to the one-way speed control valve (10) and the C chamber of the swing hydraulic cylinder (13). The shuttle valve (9) 8) and the shut-off valve (9) are connected in parallel between the two branches. When the shut-off valve (9) is closed, the swing hydraulic cylinder (13) remains in a pressurized driving state. When the shut-off valve (9) is open, the swing hydraulic cylinder (13) remains in a non-pressurized state. The swing hydraulic cylinder (13) is provided with a push-pull mechanism, which is used to drive the main shaft of the swing hydraulic cylinder (13) to rotate. The upstream of the proportional directional valve (7) is connected to the second oil tank (62). The oil inlet end of the proportional directional valve (7) is connected to the second pressure reducing valve (52). The oil outlet end of the proportional directional valve (7) is connected to the shuttle valve (8). The hydraulic testing device includes a first pressure reducing valve (51), a first oil tank (61), a first solenoid directional valve (11), a second solenoid directional valve (12), a third solenoid directional valve (21), a fourth solenoid directional valve (22), a first check valve (31), a second check valve (32), a first reversing circuit, and a second reversing circuit. The pressure control pipeline (5) is connected to the first pressure reducing valve (51). The first check valve (31) and the second check valve (32) are connected in parallel downstream of the first pressure reducing valve (51). The first reversing circuit and the second reversing circuit... Two reversing circuits are connected in parallel downstream of the direction control pipeline. The first reversing circuit is connected in series with the first electromagnetic reversing valve (11) and the third electromagnetic reversing valve (21). The second reversing circuit is connected in series with the second electromagnetic reversing valve (12) and the fourth electromagnetic reversing valve (22). The downstream pipeline of the first reversing circuit is connected to the first hydraulic joint (1) with a rod chamber. The downstream pipeline of the second reversing circuit is connected to the second hydraulic joint (2) without a rod chamber. Both the first electromagnetic reversing valve (11) and the second electromagnetic reversing valve (12) are connected to the first oil tank (61).

2. A rotary union hydraulic test system as set forth in claim 1, wherein, A first pressure sensor (41) is installed on the pipeline leading to the first hydraulic connector (1), and a second pressure sensor (42) is installed on the pipeline leading to the second hydraulic connector (2).

3. A control method of a rotary joint hydrotest system as claimed in any one of claims 1 or 2, characterized in that, Includes the following steps: The first step is to connect the first hydraulic connector (1) on the test piece to the downstream pipeline of the first reversing circuit, and connect the second hydraulic connector (2) to the downstream pipeline of the second reversing circuit, and depressurize the first hydraulic connector (1) and the second hydraulic connector (2). In the second step, the first hydraulic connector (1) is pressurized to the second pressure, and the second hydraulic connector (2) is pressurized to the first pressure. The push-pull mechanism drives the main shaft of the swing hydraulic cylinder (13) to rotate clockwise to reach the rated angle. The third step is to depressurize the first hydraulic connector (1) and the second hydraulic connector (2); In the fourth step, the first hydraulic connector (1) is pressurized to the first pressure, the second hydraulic connector (2) is pressurized to the second pressure, and the push-pull mechanism drives the main shaft of the swing hydraulic cylinder (13) to rotate counterclockwise to reach the rated angle; Fifth step: depressurize the first hydraulic connector (1) and the second hydraulic connector (2), disconnect the first hydraulic connector (1) from the downstream pipeline of the first reversing circuit, disconnect the second hydraulic connector (2) from the downstream pipeline of the second reversing circuit, and complete the durability test of the first hydraulic connector (1) and the second hydraulic connector (2).

4. The control method of a rotary union hydrostatic test system of claim 3, wherein, In the second step, the one-way speed control valve (10) of the hydraulic drive system circuit throttles and regulates the speed on the return oil circuit.

5. The control method of a rotary union hydrostatic test system as set forth in claim 3, wherein, In the second step, the second pressure reducing valve (52) and the shuttle valve (8) are connected to the oil inlet end and the oil outlet end of the proportional directional valve (7) respectively, forming a constant pressure difference ΔP between the oil inlet end and the oil outlet end of the proportional directional valve (7).

6. The control method of a rotary union hydrostatic test system as described in claim 3, wherein, In the fourth step, the one-way speed control valve (10) is in a one-way open state and does not participate in speed regulation.

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