A high temperature test device for hydraulic cylinder

Abstract

The application discloses a kind of hydraulic cylinder high temperature test device, including heating furnace, loading cylinder, the control unit of being tested cylinder and loading cylinder control unit;The piston rod of loading cylinder is connected with the piston rod of being tested cylinder transmission;Heating furnace is equipped with the heating cavity capable of containing being tested cylinder;Being tested cylinder control unit is used to according to the movement direction of the piston rod of being tested cylinder, to the rod cavity or rodless cavity of being tested cylinder oil supplement, to adjust the load pressure of being tested cylinder;Loading cylinder control unit is used to according to test demand for the rod cavity or rodless cavity of loading cylinder oil supply, to drive the piston rod movement of loading cylinder, to drive the piston rod movement of being tested cylinder according to test predetermined movement parameter motion.The application can more truly simulate the high temperature operating condition of hydraulic cylinder, realizes the high temperature resistant performance evaluation of the whole hydraulic cylinder.

Description

Technical Field

[0001] This invention relates to a high-temperature testing device for hydraulic cylinders. Background Technology

[0002] Hydraulic cylinders are core working devices in engineering machinery, and their exposure to high temperatures is unavoidable during high-temperature operations. To improve the overall high-temperature resistance of the cylinders, researchers have implemented various targeted designs: using high-temperature resistant seals internally, applying high-temperature resistant coatings to the exterior, and adding heat insulation protection. However, due to the high difficulty, risk, and cost of conducting real-world simulation tests using the entire machine, it is difficult to perform such simulations before the cylinders are put into service to evaluate their high-temperature resistance.

[0003] Existing high-temperature testing devices for hydraulic cylinders verify the reliability of high-temperature seals by heating hydraulic oil. To improve the high-temperature resistance of hydraulic cylinders, researchers not only employ high-temperature seals inside the cylinder but also typically add heat insulation protection measures to the outside. Due to the lack of simulation of high-temperature operating conditions outside the cylinder, it is impossible to conduct a comprehensive high-temperature resistance test on the cylinder. Furthermore, to meet the requirements of high-temperature hydraulic oil, higher temperature resistance requirements are imposed on the relevant testing devices, leading to a significant increase in testing costs.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention 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 shortcomings of the prior art and provide a high-temperature testing device for hydraulic cylinders, which can realize the overall high-temperature resistance test of hydraulic cylinders and has the advantages of low cost and good economic efficiency.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution: A high-temperature testing device for hydraulic cylinders, characterized in that it includes a heating furnace, a loading cylinder, a test cylinder control unit, and a loading cylinder control unit; the piston rod of the loading cylinder is throttle-connected to the piston rod of the test cylinder. The heating furnace is equipped with a heating chamber capable of accommodating the tested oil cylinder; The test cylinder control unit is used to replenish oil to the rod chamber or rodless chamber of the test cylinder according to the movement direction of the piston rod of the test cylinder, so as to adjust the load pressure of the test cylinder. The loading cylinder control unit is used to supply oil to the rod-side or rodless-side chamber of the loading cylinder according to the test requirements, so as to drive the piston rod of the loading cylinder to move the piston rod of the test cylinder according to the predetermined motion parameters of the test.

[0007] The test cylinder control unit includes a pressure control valve assembly and an oil replenishment unit. The pressure control valve assembly includes an oil replenishment port, a first pressure port, and a second pressure port. The oil replenishment port is connected to the oil outlet of the oil replenishment unit. The first pressure port is connected to the rodless chamber of the test cylinder, and the second pressure port is connected to the rod chamber of the test cylinder. The test cylinder control unit can switch the oil inlet and outlet directions of the first pressure port and the second pressure port according to the movement direction of the piston rod of the test cylinder, and simultaneously regulate and control the load pressure of the test cylinder.

[0008] The pressure control valve group includes a first solenoid directional valve, a first relief valve group, and a check valve group; the oil replenishment unit supplies oil to the rod chamber or rodless chamber of the tested cylinder through the first solenoid directional valve and the first relief valve group, and simultaneously replenishes oil to the low-pressure chamber in both chambers of the tested cylinder through the check valve group.

[0009] The oil replenishment unit includes an oil replenishment tank and an oil replenishment motor pump set, which is used to pump the hydraulic oil from the oil replenishment tank to the pressure control valve set.

[0010] The replenishing oil pump unit is connected to the oil inlet of the first solenoid directional valve via a third check valve. The oil inlet and return port of the first solenoid directional valve are respectively connected to the replenishing oil tank, so that the hydraulic oil in the first solenoid directional valve can flow back to the replenishing oil tank when switching.

[0011] The loading cylinder control unit includes a loading control valve assembly and an oil supply unit. The loading control valve assembly includes an oil supply port, a first loading port, and a second loading port. The oil supply port is connected to the oil outlet of the oil supply unit. The first loading port is connected to the rodless chamber of the loading cylinder, and the second loading port is connected to the rod chamber of the loading cylinder. The loading cylinder control unit can switch the oil inlet and outlet directions of the first loading port and the second loading port according to the movement direction of the piston rod of the loading cylinder.

[0012] The loading control valve group includes a second solenoid directional valve, a throttle valve, a second relief valve, and a directional unloading valve; The oil supply unit supplies oil to the rod-side or rodless chamber of the loading cylinder through the second electromagnetic reversing valve, the throttle valve, and the oil supply unit. The oil supply unit is also connected to the reversing unloading valve through the second overflow valve to realize low-pressure unloading and maximum pressure protection of the oil supply unit.

[0013] The oil supply unit includes a loading oil tank and a loading oil motor pump group, which is used to pump the hydraulic oil from the loading oil tank to the loading control valve group.

[0014] The loading control valve group is also equipped with a second pressure sensor for detecting the pressure at the oil outlet of the oil supply unit. The second overflow valve and the reversing unloading valve perform low-pressure unloading and maximum pressure protection on the oil supply unit according to the pressure at the oil outlet of the oil supply unit.

[0015] The heating furnace includes an acceleration rate adjustment unit, a heating temperature adjustment unit, and a holding time adjustment unit, which are used to adjust the heating rate, heating temperature, and holding time of the heating furnace, respectively.

[0016] A cooling system is also connected to the oil circuit between the test cylinder control unit and the test cylinder.

[0017] The heating furnace is provided with multiple through holes. The piston rod of the loading cylinder is connected to the test cylinder through one of the through holes. The test cylinder control unit connects the oil pipe to the test cylinder through the other through holes. Heat insulation felt is provided around the through holes.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The high-temperature testing device for hydraulic cylinders provided by this invention places the test cylinder in a heating furnace to simulate the high-temperature operating conditions outside the hydraulic cylinder. A loading cylinder located outside the heating furnace drives the test cylinder to reciprocate. Compared with the prior art that uses heating of hydraulic oil, the high-temperature testing device for hydraulic oil provided by this invention can more realistically simulate the high-temperature operating conditions of the hydraulic cylinder and realize the overall high-temperature resistance performance evaluation of the hydraulic cylinder. In addition, the testing device provided by this invention, except for the test cylinder, has all other related components arranged outside the heating furnace, which reduces the temperature resistance requirements of the testing device, thereby reducing the manufacturing cost and operating cost of the testing device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a high-temperature testing device for hydraulic cylinders provided in an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of hydraulic circuit connection for medium-pressure control valve assembly; Figure 3 yes Figure 1 Schematic diagram of hydraulic circuit connection for the medium-load control valve group; In the diagram: 1. Heating furnace; 2. Pressure control valve assembly; 201. First solenoid directional valve; 202. First overflow valve assembly; 203. Temperature sensor; 204. First pressure sensor; 205. Check valve assembly; 206. Third check valve; 3. Oil replenishment motor pump assembly; 4. Oil replenishment tank; 5. Test cylinder; 6. Loading cylinder; 7. Loading control valve assembly; 701. Second solenoid directional valve; 702. Throttle valve; 703. Second pressure sensor; 704. Reversing unloading valve; 705. Second overflow valve; 706. Fourth check valve; 8. Loading oil motor pump assembly; 9. Loading tank; 10. Insulation felt; 11. Cooling system; 12. First oil pipe of the test cylinder; 13. Second oil pipe of the test cylinder; 14. First oil pipe of the loading cylinder; 15. Second oil pipe of the loading cylinder. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0021] like Figure 1 As shown, this is a high-temperature testing device for a hydraulic cylinder provided in an embodiment of the present invention, including a heating furnace 1, a loading cylinder 6, a control unit for the tested cylinder 5, and a control unit for the loading cylinder 6.

[0022] The piston rod of the loading cylinder 6 is connected to the piston rod of the tested cylinder 5 via a transmission connection. Specifically, the two piston rods can be set at the same horizontal height and connected by intermediate structural components such as couplings; alternatively, the two piston rods can be located at different horizontal heights, and the height difference between the two piston rods can be compensated by selecting appropriate intermediate docking fixtures to achieve horizontal transmission.

[0023] The heating furnace 1 is used to simulate the external high temperature working conditions of the tested hydraulic cylinder. The heating furnace 1 is provided with a heating chamber, and the tested cylinder 5 is fixed in the heating chamber.

[0024] The control unit of the tested cylinder 5 is used to replenish oil to the rod chamber or rodless chamber of the tested cylinder 5 by the self-replenishing oil unit according to the movement direction of the piston rod of the tested cylinder 5, so as to adjust the load pressure of the tested cylinder 5, thereby simulating the reciprocating motion of the tested cylinder 5 under a certain load in a high temperature environment.

[0025] The control unit of the loading cylinder 6 is used to supply oil to the rod-side or rodless-side chamber of the loading cylinder 6 according to the test requirements, so as to drive the piston rod of the loading cylinder 6 to move, thereby causing the piston rod of the tested cylinder 5 to move according to the predetermined motion parameters of the test. During the test, the reciprocating speed, displacement, and frequency of the piston rod of the loading cylinder 6 can be adjusted indirectly to regulate the reciprocating speed, displacement, and frequency of the piston rod of the tested cylinder 5.

[0026] In summary, the high-temperature testing device for hydraulic cylinders provided in this embodiment of the invention places the test cylinder 5 in a heating furnace 1 to simulate the high-temperature working conditions outside the hydraulic cylinder. A loading cylinder 6 located outside the heating furnace 1 drives the test cylinder 5 to reciprocate. Compared with the prior art that uses heating of hydraulic oil, the high-temperature testing device for hydraulic oil provided by this invention can more realistically simulate the high-temperature working conditions of the hydraulic cylinder and realize the overall high-temperature resistance performance evaluation of the hydraulic cylinder. In addition, the testing device provided by this invention, except for the test cylinder 5, has all other related components arranged outside the heating furnace 1, which reduces the temperature resistance requirements of the testing device, thereby reducing the manufacturing cost and operating cost of the testing device.

[0027] In one embodiment of the present invention, the control unit of the tested cylinder 5 may include a pressure control valve assembly 2 and an oil replenishment unit; the pressure control valve assembly 2 includes an oil replenishment port, a first pressure oil port, and a second pressure oil port. The oil replenishment port is connected to the oil outlet of the oil replenishment unit. The first pressure oil port is connected to the rodless chamber of the tested cylinder 5 through a first oil pipe 12 of the tested cylinder, and the second pressure oil port is connected to the rod chamber of the tested cylinder 5 through a second oil pipe 13 of the tested cylinder. The control unit of the tested cylinder 5 can switch the oil inlet and outlet directions of the first pressure oil port and the second pressure oil port according to the movement direction of the piston rod of the tested cylinder 5, so as to regulate and control the load pressure of the tested cylinder 5. Specifically, refer to... Figure 1 When the piston rod of the tested cylinder 5 extends, the second pressure port serves as the return port, and hydraulic oil flows back from the rod chamber of the tested cylinder 5 to the pressure control valve group 2. The first pressure port serves as the outlet port, and hydraulic oil flows from the pressure control valve to the rodless chamber of the tested cylinder 5. When the piston rod of the tested cylinder 5 retracts, conversely, the first pressure port serves as the return port, and hydraulic oil flows back from the rodless chamber of the tested cylinder 5 to the pressure control valve group 2. The second pressure port serves as the outlet port, and hydraulic oil flows from the pressure control valve to the rod chamber of the tested cylinder 5.

[0028] In some embodiments of the present invention, the oil replenishment unit may include an oil replenishment tank 4 and an oil replenishment motor pump group 3. The oil replenishment motor pump group 3 is used to deliver the hydraulic oil in the oil replenishment tank 4 to the pressure control valve group 2 to replenish the oil in the tested cylinder 5. The oil replenishment motor pump group 3 can use a low-power motor to meet the power requirements for oil replenishment.

[0029] See Figure 2In one embodiment of the present invention, the pressure control valve group 2 includes a first solenoid directional valve 201, a first relief valve group 202, and a check valve group 205. The oil replenishment unit provides a driving oil source for no-load reciprocating motion to the oil circuit through the first solenoid directional valve 201, and the oil replenishment unit replenishes oil to the rod chamber or rodless chamber of the tested cylinder through the first relief valve group 202 and the check valve group 205 (typically with a maximum pressure of 30 MPa). It can be understood that the first solenoid directional valve 201 is used to switch the inlet and outlet directions of the first pressure port and the second pressure port. The first relief valve group 202 can control the hydraulic pressure entering the rod chamber and rodless chamber of the tested cylinder through relief. The first relief valve group 202 may include a relief valve connected to the rod chamber of the tested cylinder and a relief valve connected to the rodless chamber of the tested cylinder. The one-way valve assembly 205 may include a first one-way valve and a second one-way valve. The oil replenishment unit can replenish oil to the low-pressure chamber in the two chambers of the tested oil cylinder through the one-way valve assembly 205 to prevent the tested oil cylinder from being sucked into the air.

[0030] The replenishing oil pump unit 3 is connected to the oil inlet of the first electromagnetic directional valve 201 via the third check valve 206. The oil inlet and return port of the first electromagnetic directional valve 201 are respectively connected to the replenishing oil tank 4, so that the hydraulic oil in the first electromagnetic directional valve 201 can flow back to the replenishing oil tank 4 when switching.

[0031] In some embodiments of the present invention, the control unit of the loading cylinder 6 may include a loading control valve group 7 and an oil supply unit. The loading control valve group 7 includes an oil supply port, a first loading port, and a second loading port. The oil supply port is connected to the oil outlet of the oil supply unit. The first loading port is connected to the rodless chamber of the loading cylinder 6 through a first oil pipe 14 of the loading cylinder. The second loading port is connected to the rod chamber of the loading cylinder 6 through a second oil pipe 15 of the loading cylinder. The control unit of the loading cylinder 6 can complete the reversing movement of the piston rod of the loading cylinder 6 and the switching of the oil inlet and outlet directions of the first loading port and the second loading port according to the test requirements. Specifically: when the piston rod of the tested cylinder 5 extends, the piston rod of the corresponding loading cylinder 6 retracts. The first loading port serves as the return port, and hydraulic oil flows back from the rodless chamber of the loading cylinder 6 to the loading control valve group 7. The second loading port serves as the outlet port, and hydraulic oil flows from the drive control valve to the rod chamber of the loading cylinder 6. When the piston rod of the tested cylinder 5 retracts, the piston rod of the corresponding loading cylinder 6 extends. At this time, the second loading port serves as the return port, and hydraulic oil flows back from the rod chamber of the loading cylinder 6 to the loading control valve group 7. The first loading port serves as the outlet port, and hydraulic oil flows from the drive control valve to the rodless chamber of the loading cylinder 6.

[0032] Optionally, the oil supply unit includes a loading oil tank 9 and a loading oil motor pump group 8, wherein the loading oil motor pump group 8 is used to deliver the hydraulic oil in the loading oil tank 9 to the oil supply port.

[0033] See Figure 3 This is a schematic diagram of the hydraulic oil circuit connection of a loading control valve group provided in an embodiment of the present invention.

[0034] The loading control valve group 7 may include a second solenoid directional valve 701, a throttle valve 702, a second relief valve 705, and a directional unloading valve 704. The oil supply unit supplies oil to the rod-side or rodless chamber of the loading cylinder via the second electromagnetic reversing valve 701 and the throttle valve 702. The second electromagnetic reversing valve 701 switches the oil inlet and outlet directions of the first and second loading ports, thereby reversing the piston rod movement of the loading cylinder. The throttle valve 702 is used for flow control and speed regulation, adjusting the oil flow rate and pressure to regulate the piston rod speed. The oil supply unit is also connected to the reversing unloading valve 704 via the second overflow valve 705. A second pressure sensor 703 is installed at the oil outlet of the oil supply unit to detect the pressure at the outlet. The reversing unloading valve 704 and the second overflow valve 705 provide low-pressure unloading and maximum-pressure protection for the oil supply unit based on the pressure at its outlet.

[0035] In one embodiment of the present invention, the oil supply unit may include a loading oil tank 9 and a loading oil motor pump assembly 8, wherein the loading oil motor pump assembly 8 is used to pump hydraulic oil from the loading oil tank 9 to the loading control valve assembly 7. The loading oil motor pump assembly 8 is connected to the oil supply port of the loading control valve assembly 7 via a fourth check valve.

[0036] To adapt to the needs of different test conditions, the heating furnace 1 includes an acceleration rate adjustment unit, a heating temperature adjustment unit, and a holding time adjustment unit, which are used to adjust the heating rate, heating temperature, and holding time of the heating furnace 1, respectively. The heating method of the heating furnace 1 can be electric heating, gas heating, hot air heating, etc., and its heating rate can be controlled within the range of 3~50℃ / min, and its temperature can be controlled within the range of room temperature~1500℃.

[0037] To ensure the tested oil cylinder 5 is in a relatively sealed test environment, the heating furnace 1 can have multiple through holes as needed for connecting the oil pipes and piston rods. The piston rod of the loading cylinder 6 is connected to the tested oil cylinder 5 through one of the through holes, and the control unit of the tested oil cylinder 5 connects the oil pipes to the tested oil cylinder 5 through the remaining through holes. To reduce heat loss within the furnace, heat insulation felt 10 is arranged around the through holes.

[0038] The hydraulic oil flowing from the test cylinder 5 is typically at a high temperature. To maintain the ambient temperature of all components outside the heating furnace 1, a cooling system 11 is connected to the oil circuit between the control unit of the test cylinder 5 and the test cylinder 5. The cooling system 11 can be water-cooled, air-cooled, or liquid nitrogen-cooled, etc., and can cool the hydraulic oil through the connecting oil pipe of the test cylinder 5. Therefore, in this application, all components except the test cylinder 5 are in an ambient temperature environment, eliminating the need for high-temperature resistant components. The test scheme can be implemented using conventional motor pump sets and control valve sets, resulting in low overall manufacturing and operating costs, stable operation, and high reliability and safety.

[0039] In order to detect the temperature of the hydraulic oil after cooling by the cooling system 11 and the oil pressure in the pipeline, a temperature sensor 203 for detecting the hydraulic oil temperature and a first pressure sensor 204 for detecting the hydraulic oil pressure in the pipeline are also provided on the pipeline between the cooling system 11 and the first relief valve group.

[0040] The specific testing method of the testing device provided in this embodiment of the invention is explained below: First, the test cylinder 5 is fixed in the heating chamber of the heating furnace 1. According to the test requirements, the heating rate, holding temperature, running time, and other parameters of the heating furnace are set to simulate the high-temperature working condition of the test cylinder. The piston rod of the loading cylinder 6 and the piston rod of the test cylinder 5 are connected by a connecting fixture. The driving oil pump motor 8 of the loading cylinder 6 drives the oil supply. The room temperature hydraulic oil in the loading oil tank 9 passes through the loading control valve group 7. The loading control valve group 7 controls the flow rate and direction of the hydraulic oil flowing through the first oil pipe 14 and the second oil pipe 15 of the loading cylinder, and adjusts the displacement and reciprocating speed of the loading cylinder 6. The loading cylinder 6 drives the test cylinder 5, providing the reciprocating stroke, speed, and frequency required for the test of the test cylinder 5. When the tested cylinder 5 is passively reciprocating, its oil replenishment motor pump group 3 drives the oil replenishment, and its pressure control valve group 2 controls the hydraulic oil to provide load pressure to the tested cylinder 5. The hydraulic oil in the oil replenishment tank 4 automatically replenishes the tested cylinder 5 through the first oil pipe 12 and the second oil pipe 13 of the tested cylinder.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature testing device for hydraulic cylinders, characterized in that, It includes a heating furnace, a loading cylinder, a test cylinder control unit, and a loading cylinder control unit; the piston rod of the loading cylinder is connected to the piston rod of the test cylinder in a transmission connection. The heating furnace is equipped with a heating chamber that can accommodate the test cylinder, which is used to simulate the high-temperature working conditions outside the test cylinder. The test cylinder control unit is used to replenish oil to the rod chamber or rodless chamber of the test cylinder according to the movement direction of the piston rod of the test cylinder, so as to adjust the load pressure of the test cylinder. The loading cylinder control unit is used to supply oil to the rod chamber or rodless chamber of the loading cylinder according to the test requirements, so as to drive the piston rod of the loading cylinder to move the piston rod of the test cylinder according to the predetermined motion parameters of the test. The test cylinder control unit includes a pressure control valve group (2) and an oil replenishment unit; the pressure control valve group (2) includes an oil replenishment port, a first pressure oil port and a second pressure oil port, the oil replenishment port is connected to the oil outlet of the oil replenishment unit, the first pressure oil port is connected to the rodless chamber of the test cylinder, and the second pressure oil port is connected to the rod chamber of the test cylinder. The test cylinder control unit can switch the oil inlet and outlet directions of the first pressure oil port and the second pressure oil port according to the movement direction of the piston rod of the test cylinder, and at the same time adjust and control the load pressure of the test cylinder. The pressure control valve group (2) includes a first solenoid directional valve (201), a first overflow valve group (202), and a check valve group (205); the oil replenishment unit can supply oil to the rod chamber or rodless chamber of the tested cylinder through the first solenoid directional valve (201) and the first overflow valve, and replenish oil to the low-pressure chamber in the two chambers of the tested cylinder through the check valve group (205); The oil replenishment unit includes an oil replenishment tank (4) and an oil replenishment motor pump group (3). The oil replenishment motor pump group (3) is used to pump the hydraulic oil from the oil replenishment tank (4) to the pressure control valve group (2). The replenishing oil pump unit (3) is connected to the oil inlet of the first electromagnetic reversing valve (201) through the third check valve (206). The oil inlet and return port of the first electromagnetic reversing valve (201) are respectively connected to the replenishing oil tank (4) so ​​that the hydraulic oil in the first electromagnetic reversing valve (201) can flow back to the replenishing oil tank (4) when reversing.

2. The high-temperature testing device for hydraulic cylinders according to claim 1, characterized in that, The loading cylinder control unit includes a loading control valve group (7) and an oil supply unit. The loading control valve group includes an oil supply port, a first loading port, and a second loading port. The oil supply port is connected to the oil outlet of the oil supply unit. The first loading port is connected to the rodless chamber of the loading cylinder, and the second loading port is connected to the rod chamber of the loading cylinder. The loading cylinder control unit can switch the oil inlet and outlet directions of the first loading port and the second loading port according to the movement direction of the piston rod of the loading cylinder.

3. The high-temperature testing device for hydraulic cylinders according to claim 2, characterized in that, The loading control valve group (7) includes a second solenoid directional valve (701), a throttle valve (702), a second relief valve (705), and a directional unloading valve (704). The oil supply unit supplies oil to the rod-side or rodless-side chamber of the loading cylinder through the second electromagnetic reversing valve (701), the throttle valve (702); the oil supply unit is also connected to the reversing unloading valve (704) through the second overflow valve (705) to realize low-pressure unloading and maximum pressure protection of the oil supply unit.

4. The high-temperature testing device for hydraulic cylinders according to claim 2 or 3, characterized in that, The oil supply unit includes a loading oil tank (9) and a loading oil motor pump group (8), which is used to pump the hydraulic oil from the loading oil tank (9) to the loading control valve group (7).

5. The high-temperature testing device for hydraulic cylinders according to claim 3, characterized in that, The loading control valve group (7) is also equipped with a second pressure sensor (703) for detecting the pressure at the oil outlet of the oil supply unit. The reversing unloading valve (704) and the second overflow valve (705) perform low-pressure unloading and maximum pressure protection on the oil supply unit according to the pressure at the oil outlet of the oil supply unit.

6. The high-temperature testing device for hydraulic cylinders according to claim 1, characterized in that, The heating furnace includes an acceleration rate adjustment unit, a heating temperature adjustment unit, and a holding time adjustment unit, which are used to adjust the heating rate, heating temperature, and holding time of the heating furnace, respectively.

7. The high-temperature testing device for hydraulic cylinders according to claim 1, characterized in that, A cooling system is also connected to the oil circuit between the test cylinder control unit and the test cylinder.

8. The high-temperature testing device for hydraulic cylinders according to claim 1, characterized in that, The heating furnace is provided with multiple through holes. The piston rod of the loading cylinder is connected to the test cylinder through one of the through holes. The test cylinder control unit connects the oil pipe to the test cylinder through the other through holes. Heat insulation felt is provided around the through holes.

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