Hydraulic cylinder test system and method

Abstract

The invention discloses a hydraulic cylinder testing system and method, and relates to the technical field of hydraulic cylinder tests.The hydraulic cylinder testing system comprises a tested cylinder, a loading cylinder, a liquid tank, a liquid pump and a pressure adjusting loop, and a rodless cavity of the tested cylinder is connected with the liquid tank and the liquid pump to form a first liquid supply loop; a rod cavity of the tested cylinder is connected with the liquid tank and the liquid pump to form a second liquid supply loop, and a rod cavity of the loading cylinder is connected with the liquid tank and the pressure adjusting loop to form a third liquid supply loop. A rodless cavity of the loading cylinder is respectively connected with the liquid tank and the pressure regulating loop to form a fourth liquid supply loop, and each liquid supply loop is provided with a hydraulic control reversing valve and a hydraulic control one-way valve to control the on-off of the corresponding liquid supply loop and the flow direction of the liquid, so that the tested cylinder is tested. The test system can be used for carrying out a non-load test, a durability test, a leakage test and a withstand voltage test.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder testing technology, and in particular to a hydraulic cylinder testing system and method. Background Technology

[0002] A hydraulic cylinder is an actuator in a hydraulic system that converts hydraulic energy into mechanical energy. The space inside a hydraulic cylinder is divided into a rod chamber and a rodless chamber by a piston. When fluid flows into the rodless chamber and out of the rod chamber, the piston rod extends. When fluid flows into the rod chamber and out of the rodless chamber, the piston rod retracts. Hydraulic cylinders require testing to verify their performance, primarily including no-load tests, leakage tests, durability tests, and pressure tests.

[0003] If the piston rod is not under any force when the hydraulic cylinder extends or retracts, and the pressure of the inlet fluid is almost zero, this is called a no-load test. During leakage tests, durability tests, and pressure tests, a certain force needs to be applied to the piston rod to bring the fluid in the rodless or rod-side chamber to a certain pressure.

[0004] National standards only allow leakage tests to be performed on the cylinder at two positions: fully extended and fully retracted. However, the industry requires leakage tests to be performed on the hydraulic cylinder piston rod at positions such as 0%, 25%, 50%, 75%, and 100% extension.

[0005] The following shortcomings exist in current hydraulic cylinder testing:

[0006] (1) The test system has a single function and requires multiple different test systems to carry out different test items, resulting in low efficiency and high cost.

[0007] (2) The position of the baffle needs to be adjusted in the leakage test to conduct leakage tests on the hydraulic cylinder piston rod at different positions, which is time-consuming, labor-intensive and inefficient.

[0008] (3) The test system uses multiple pumps to supply liquid to the test cylinder and the loading cylinder respectively, which makes the system complex and costly.

[0009] (4) There is a lack of methods in the industry to simulate the actual working conditions of hydraulic cylinders on site, and the life of hydraulic cylinders obtained in the test is far from the life of actual use. Summary of the Invention

[0010] The present invention aims to at least solve the technical problems existing in the prior art, such as the need for multiple different test systems to conduct different test items, low efficiency, high cost, system complexity, and large gap between the hydraulic cylinder life obtained in the test and the actual life in use.

[0011] Therefore, one object of the present invention is to provide a hydraulic cylinder testing system, including a test cylinder, a loading cylinder, a liquid tank, a liquid pump, and a pressure regulating circuit. The piston rods of the loading cylinder and the test cylinder are connected abuttingly. The rodless chamber of the test cylinder is connected to the liquid tank and the liquid pump to form a first liquid supply circuit. The rod chamber of the test cylinder is connected to the liquid tank and the liquid pump to form a second liquid supply circuit. The rod chamber of the loading cylinder is connected to the liquid tank and the pressure regulating circuit to form a third liquid supply circuit. The rodless chamber of the loading cylinder is connected to the liquid tank and the pressure regulating circuit to form a fourth liquid supply circuit. Each of the first, second, third, and fourth liquid supply circuits is equipped with a hydraulically controlled directional valve and a hydraulically controlled check valve to control the on / off state and liquid flow direction of the corresponding liquid supply circuit, thereby testing the test cylinder.

[0012] In some embodiments, the first liquid supply circuit is provided with a first hydraulically controlled directional valve and a first hydraulically controlled check valve. The rodless chamber of the test cylinder is connected to the first interface of the first hydraulically controlled directional valve through a first pipeline. The second interface of the first hydraulically controlled directional valve is connected to the liquid tank. The third interface of the first hydraulically controlled directional valve is connected to the liquid pump. The first hydraulically controlled check valve is disposed on the first pipeline. The second liquid supply circuit is provided with a second hydraulically controlled directional valve and a second hydraulically controlled check valve. The rod chamber of the test cylinder is connected to the first interface of the second hydraulically controlled directional valve through a second pipeline. The second interface of the second hydraulically controlled directional valve is connected to the liquid tank. The third interface of the second hydraulically controlled directional valve is connected to the liquid pump. The second hydraulically controlled check valve is disposed on the second pipeline. The third liquid supply circuit is equipped with a third hydraulically controlled directional valve and a third hydraulically controlled check valve. The rodless chamber of the loading cylinder is connected to the first interface of the third hydraulically controlled directional valve through a third pipeline. The second interface of the third hydraulically controlled directional valve is connected to the liquid tank. The third interface of the third hydraulically controlled directional valve is connected to the pressure regulating circuit. The third hydraulically controlled check valve is located on the third pipeline. The fourth liquid supply circuit is equipped with a fourth hydraulically controlled directional valve and a fourth hydraulically controlled check valve. The rod chamber of the loading cylinder is connected to the first interface of the fourth hydraulically controlled directional valve through a fourth pipeline. The second interface of the fourth hydraulically controlled directional valve is connected to the liquid tank. The third interface of the fourth hydraulically controlled directional valve is connected to the pressure regulating circuit. The third hydraulically controlled check valve is located on the fourth pipeline.

[0013] In some embodiments, a first adjustable flow valve is provided on the first pipeline between the first hydraulic check valve and the first interface of the first hydraulic directional valve; a second adjustable flow valve is provided on the second pipeline between the second hydraulic check valve and the first interface of the second hydraulic directional valve.

[0014] In some embodiments, the hydraulic cylinder testing system further includes a first pilot valve, a second pilot valve, a third pilot valve, a fourth pilot valve, a fifth pilot valve, a sixth pilot valve, a seventh pilot valve, and an eighth pilot valve. The first hydraulically controlled directional valve is connected to the first pilot valve; the second hydraulically controlled directional valve is connected to the second pilot valve; the third hydraulically controlled directional valve is connected to the third pilot valve; the fourth hydraulically controlled directional valve is connected to the fourth pilot valve; the first hydraulically controlled check valve is connected to the fifth pilot valve; the second hydraulically controlled check valve is connected to the sixth pilot valve; the third hydraulically controlled check valve is connected to the seventh pilot valve; and the fourth hydraulically controlled check valve is connected to the eighth pilot valve.

[0015] In some embodiments, a proportional relief valve is provided on the pressure regulating circuit.

[0016] In some embodiments, a throttling valve is further provided on the pipeline connecting the liquid pump and the proportional relief valve.

[0017] Another aspect of the present invention provides a hydraulic cylinder testing method, implemented using the hydraulic cylinder testing system described in any of the preceding claims. A first pressure sensor is provided on the first pipeline between the rodless chamber of the test cylinder and the first hydraulically controlled check valve; a second pressure sensor is provided on the second pipeline between the rod chamber of the test cylinder and the second hydraulically controlled check valve; a third pressure sensor is provided on the third pipeline between the rod chamber of the loading cylinder and the third hydraulically controlled check valve; and a fourth pressure sensor is provided on the fourth pipeline between the rodless chamber of the loading cylinder and the fourth hydraulically controlled check valve.

[0018] Another aspect of the present invention provides a hydraulic cylinder testing method, which is implemented using the hydraulic cylinder testing system described in any of the above claims. A slider is connected between the piston rod of the loading cylinder and the piston rod of the test cylinder. A first displacement sensor is provided on the test cylinder, a second displacement sensor is provided on the loading cylinder, and a third displacement sensor is provided on the slider.

[0019] Another aspect of the present invention provides a hydraulic cylinder testing method, implemented using the hydraulic cylinder testing system described in any of the preceding claims, comprising, during a no-load test:

[0020] Both the rod-side chamber and the rodless chamber of the loading cylinder are connected to the liquid tank;

[0021] When the test cylinder extends, the rodless chamber of the test cylinder is connected to the liquid pump, and its rod chamber is connected to the liquid tank; when the test cylinder retracts, the rodless chamber of the test cylinder is connected to the liquid tank, and its rod chamber is connected to the liquid pump.

[0022] Another aspect of the present invention provides a hydraulic cylinder testing method, implemented using the hydraulic cylinder testing system described in any of the preceding claims, comprising the following steps when conducting a durability test:

[0023] When the test cylinder is extended, the rodless chamber of the test cylinder is connected to the liquid pump, the rod chamber of the test cylinder is connected to the liquid tank, the rodless chamber of the loading cylinder is connected to the pressure regulating circuit, and the rod chamber of the loading cylinder is connected to the liquid tank.

[0024] When the test cylinder is retracted, the rodless chamber of the test cylinder is connected to the liquid tank, the rod chamber of the test cylinder is connected to the liquid pump, the rod chamber of the loading cylinder is connected to the pressure regulating circuit, and the rodless chamber of the loading cylinder is connected to the liquid tank.

[0025] Another aspect of the present invention provides a hydraulic cylinder testing method, implemented using the hydraulic cylinder testing system described in any of the above claims, comprising: [The method includes] conducting a rodless chamber leakage test on the tested cylinder, including:

[0026] Both the rod-side chamber and the rodless chamber of the loading cylinder are connected to the liquid tank. The test cylinder can be extended or retracted to the designated test position under no-load conditions.

[0027] Upon reaching the designated test position, the fourth liquid supply circuit connected to the rodless chamber of the loading cylinder is disconnected. The rod chambers of the loading cylinder and the rod chamber of the test cylinder are both connected to the liquid tank, and the rodless chamber of the test cylinder is connected to the liquid pump. The liquid pump pressure is adjusted to the test pressure, and the working pressure of the pressure adjustment circuit is adjusted to 0.

[0028] De-energize the hydraulic control check valve in the first liquid supply circuit and wait for both the rodless chamber of the test cylinder and the rodless chamber of the loading cylinder to rise to the pump pressure.

[0029] De-energize the hydraulic control directional valve in the first liquid supply circuit to cut off the first liquid supply circuit to the rodless chamber of the test cylinder; maintain pressure as required and observe the pressure changes in the rodless chamber of the test cylinder and the rodless chamber of the loading cylinder.

[0030] Another aspect of the present invention provides a hydraulic cylinder testing method, implemented using the hydraulic cylinder testing system described in any of the above claims, comprising: [The method includes] conducting a rodless chamber leakage test on the tested cylinder, including:

[0031] Collect data on the changes in load pressure on the hydraulic cylinders at the site;

[0032] The working pressure of the pressure regulating circuit is adjusted according to the changes in the load pressure of the hydraulic cylinder at the site to evaluate the life of the cylinder under test.

[0033] The present invention provides a hydraulic cylinder testing system, which has the following beneficial effects:

[0034] This invention is a multifunctional hydraulic cylinder testing system consisting of a pilot valve, a hydraulically controlled directional valve, a hydraulically controlled check valve, an adjustable flow valve, and a proportional relief valve.

[0035] The combination of pilot valves, hydraulically controlled directional valves, hydraulically controlled check valves, throttle valves, and proportional relief valves in the pressure regulation circuits of each liquid supply circuit enables no-load and loaded tests of the test cylinder. This invention uses only one proportional relief valve and one liquid pump to achieve the loading actions of cylinder extension and retraction. The combination of pilot valves, hydraulically controlled directional valves, and hydraulically controlled check valves allows leakage tests to be performed on the piston rod of the test cylinder at any position, meeting the industry's need for leak testing at multiple locations.

[0036] The test cylinders with different diameters are adapted to be tested by adjusting the first and second adjustable flow valves. The working pressure of the test cylinder is adjusted by adjusting the working pressure of the proportional relief valve, and the pressure of the proportional relief valve is controlled to change in real time according to the actual working conditions of the test cylinder, so as to realize the simulation of the actual working conditions of the hydraulic cylinder. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of a hydraulic cylinder testing system according to an embodiment of the present invention.

[0039] Figure label:

[0040] 10. First pilot valve; 11. Second pilot valve; 12. Third pilot valve; 13. Fourth pilot valve; 14. Fifth pilot valve; 15. Sixth pilot valve; 16. Seventh pilot valve; 17. Eighth pilot valve; 21. First hydraulically controlled directional valve; 22. Second hydraulically controlled directional valve; 23. Third hydraulically controlled directional valve; 24. Fourth hydraulically controlled directional valve; 31. First hydraulically controlled check valve; 32. Second hydraulically controlled check valve; 33. Third hydraulically controlled check valve; 34. Fourth hydraulically controlled check valve; 41. First pressure sensor 42. Second pressure sensor; 43. Third pressure sensor; 44. Fourth pressure sensor; 45. First displacement sensor; 46. Second displacement sensor; 47. Third displacement sensor; 51. Test cylinder; 52. Loading cylinder; 61. First adjustable flow valve; 62. Second adjustable flow valve; 63. Throttle valve; 71. Proportional relief valve; 81. Slider; 100. First liquid supply circuit; 200. Second liquid supply circuit; 300. Third liquid supply circuit; 400. Fourth liquid supply circuit. Detailed Implementation

[0041] Various aspects and features of the present invention are described herein with reference to the accompanying drawings.

[0042] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of the invention will be apparent to those skilled in the art.

[0043] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

[0044] These and other features of the invention will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0045] It should also be understood that although the invention has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of the invention, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0046] The above and other aspects, features and advantages of the invention will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0047] Specific embodiments of the invention are described below with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of the invention, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the invention. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use the invention in various ways with substantially any suitable detailed structure.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0049] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0050] In the description of this invention, "a plurality of" means two or more.

[0051] In the description of this invention, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0052] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0053] In the description of this invention, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0055] like Figure 1As shown, the first embodiment of this disclosure provides a hydraulic cylinder testing system, including a test cylinder 51, a loading cylinder 52, a liquid tank, a liquid pump, and a pressure regulating circuit. The piston rod of the loading cylinder 52 and the piston rod of the test cylinder 51 are connected abuttingly, and the movement of the piston rod of the test cylinder 51 can drive the movement of the piston rod of the loading cylinder 52. The rodless chamber of the test cylinder 51 is connected to the liquid tank and the liquid pump to form a first liquid supply circuit 100, and the rod chamber of the test cylinder 51 is connected to the liquid tank and the liquid pump to form a second liquid supply circuit 200. The rod-side chamber of the loading cylinder 52 is connected to the liquid tank and the pressure regulating circuit to form a third liquid supply circuit 300. The rodless chamber of the loading cylinder 52 is connected to the liquid tank and the pressure regulating circuit to form a fourth liquid supply circuit 400. The first liquid supply circuit 100, the second liquid supply circuit 200, the third liquid supply circuit 300 and the fourth liquid supply circuit 400 are all equipped with hydraulic control directional valves and hydraulic control check valves to control the on / off of the corresponding liquid supply circuits and the direction of liquid flow, thereby conducting no-load tests, durability tests (i.e., loading tests), leakage tests and pressure resistance tests on the test cylinder.

[0056] Furthermore, the rodless chamber of the test cylinder 51 is connected to a first liquid supply circuit 100, through which liquid is supplied to the rodless chamber of the test cylinder 51 by the liquid pump, or the liquid in the rodless chamber of the test cylinder 51 flows out to the liquid tank; the rod chamber of the test cylinder 51 is connected to a second liquid supply circuit 200, through which liquid is supplied to the rod chamber of the test cylinder 51 by the liquid pump, or the liquid in the rod chamber of the test cylinder 51 flows out to the liquid tank through the second liquid supply circuit 200; by controlling the on / off state of the first liquid supply circuit 100 and the second liquid supply circuit 200 and the direction of liquid flow, the extension or retraction of the test cylinder 51 can be achieved;

[0057] Specifically, the first liquid supply circuit 100 is provided with a first hydraulically controlled check valve 31 and a first hydraulically controlled directional valve 21 in sequence from the direction near the test cylinder 51 to the direction away from the test cylinder 51; the second liquid supply circuit 200 is provided with a second hydraulically controlled check valve 32 and a second hydraulically controlled directional valve 22 in sequence from the direction near the test cylinder 51 to the direction away from the test cylinder 51; when the test cylinder 51 extends, the first hydraulically controlled directional valve 21 is connected to the liquid pump, and the second hydraulically controlled directional valve 22 is connected to the liquid tank, and the liquid passes sequentially through the liquid pump, the first hydraulically controlled directional valve 21, and the first hydraulically controlled check valve. The liquid enters the rodless chamber of the test cylinder 51. The liquid in the rod chamber of the test cylinder 51 enters the liquid tank sequentially through the second hydraulic control check valve 32 and the second hydraulic control directional valve 22. When the test cylinder 51 retracts, the first hydraulic control directional valve 21 is connected to the liquid tank, and the second hydraulic control directional valve 22 is connected to the liquid pump. The liquid in the rodless chamber of the test cylinder 51 enters the liquid tank sequentially through the first hydraulic control check valve 31 and the first hydraulic control directional valve 21. The liquid enters the rod chamber of the test cylinder 51 sequentially through the liquid pump, the second hydraulic control directional valve 22, and the second hydraulic control check valve 32.

[0058] Furthermore, the rod chamber of the loading cylinder 52 is connected to a third liquid supply circuit 300, through which liquid is supplied to the rod chamber of the loading cylinder 52, or the liquid in the rod chamber of the loading cylinder 52 flows out to the liquid tank through the third liquid supply circuit 300; the rodless chamber of the loading cylinder 52 is connected to a fourth liquid supply circuit 400, through which liquid is supplied to the rodless chamber of the loading cylinder, or the liquid in the rodless chamber of the loading cylinder 52 flows out to the liquid tank through the fourth liquid supply circuit 400; by controlling the on / off state of the third liquid supply circuit 300 and the fourth liquid supply circuit 400 and the direction of liquid flow, the extension and retraction of the loading cylinder 52 can be achieved;

[0059] Specifically, a third hydraulic control check valve 33 and a third hydraulic control directional valve 23 are sequentially connected to the third liquid supply circuit 300 in the direction from near the loading cylinder 52 to away from the loading cylinder 52; a fourth hydraulic control check valve 34 and a fourth hydraulic control directional valve 24 are sequentially connected to the fourth liquid supply circuit in the direction from near the loading cylinder 52 to away from the loading cylinder 52.

[0060] The test system also includes a pressure regulating circuit that provides working pressure when the test cylinder 51 moves. The pressure regulating circuit is equipped with a proportional relief valve 71, which is used to regulate the load pressure (i.e., the working pressure of the test cylinder) supplied by the loading cylinder 52 to the test cylinder 51. When the loading cylinder 52 extends, the third hydraulically controlled directional valve 23 is connected to the proportional relief valve 71, and the fourth hydraulically controlled directional valve 24 is directly connected to the liquid tank. The liquid in the rod chamber of the loading cylinder 52 sequentially enters the liquid tank through the third hydraulically controlled check valve 33, the third hydraulically controlled directional valve 23, and the proportional relief valve 71. The liquid in the tank enters the rodless chamber of the loading cylinder 52 sequentially through the fourth hydraulically controlled directional valve 24 and the fourth hydraulically controlled check valve, replenishing the rodless chamber of the loading cylinder 52. When the loading cylinder 52 retracts, the third hydraulically controlled directional valve 23 is directly connected to the liquid tank, and the fourth hydraulically controlled directional valve 24 is connected to the proportional overflow valve 71. The liquid in the liquid tank enters the rod chamber of the loading cylinder 52 sequentially through the third hydraulically controlled directional valve 23 and the third hydraulically controlled check valve 33. The liquid in the rodless chamber of the loading cylinder 52 enters the liquid tank sequentially through the fourth hydraulically controlled check valve 44, the fourth hydraulically controlled directional valve 24, and the proportional overflow valve 71.

[0061] In this embodiment, when the test cylinder 51 extends, the rodless chamber of the loading cylinder 52 is connected to the proportional relief valve 71, and the rod chamber of the loading cylinder 52 is directly connected to the liquid tank. The load applied by the loading cylinder 52 to the test cylinder 51 is to the left, and the load size is equal to the product of the working pressure of the proportional relief valve 71 and the piston area of ​​the loading cylinder. When the piston diameters of the loading cylinder 52 and the test cylinder 51 are the same, the working pressure of the proportional relief valve 71 is equal to the working pressure of the rodless chamber of the test cylinder 51.

[0062] When the test cylinder 51 is retracted, the rod chamber of the loading cylinder 52 is connected to the proportional relief valve 71, and the rodless chamber of the loading cylinder 52 is directly connected to the liquid tank. The load applied by the loading cylinder 52 to the test cylinder 51 is to the right, and the load size is equal to the product of the working pressure of the proportional relief valve 71 and the annular area of ​​the rod chamber of the loading cylinder 52. Since the annular diameters of the loading cylinder 52 and the test cylinder 51 are the same, the working pressure of the proportional relief valve 71 is the working pressure of the rod chamber of the test cylinder 51.

[0063] In this embodiment, to control the switching actions of the first hydraulically controlled directional valve 21, the second hydraulically controlled directional valve 22, the third hydraulically controlled directional valve 23, and the fourth hydraulically controlled directional valve 24, a first pilot valve 10 is connected to the first hydraulically controlled directional valve 21 to control its switching; a second pilot valve 11 is connected to the second hydraulically controlled directional valve 22 to control its switching; a third pilot valve 12 is connected to the third hydraulically controlled directional valve 23 to control its switching; and a fourth pilot valve 13 is connected to the fourth hydraulically controlled directional valve 24 to control its switching.

[0064] In this embodiment, to control the forward and reverse conduction functions of the first hydraulic check valve 31, the second hydraulic check valve 32, the third hydraulic check valve 33, and the fourth hydraulic check valve 34, the first hydraulic check valve 31 is connected to the fifth pilot valve 14 to control its forward and reverse conduction functions. When the fifth pilot valve 14 is energized, the first hydraulic check valve 31 conducts in both forward and reverse directions; when the fifth pilot valve 14 is de-energized, the first hydraulic check valve 31 can only conduct in the forward direction. The second hydraulic check valve 32 is connected to the sixth pilot valve 15 to control its forward and reverse conduction functions. When the sixth pilot valve 15 is energized, the second hydraulic check valve 32 conducts in both forward and reverse directions. When the sixth pilot valve 15 is de-energized, the second hydraulically controlled check valve 32 can only be forward-biased; the third hydraulically controlled check valve 33 is connected to the seventh pilot valve 16, controlling the forward and reverse conduction functions of the third hydraulically controlled check valve 33. When the seventh pilot valve 16 is energized, the third hydraulically controlled check valve 33 is conducting in both forward and reverse directions. When the seventh pilot valve 16 is de-energized, the third hydraulically controlled check valve 33 can only be forward-biased; the fourth hydraulically controlled check valve 34 is connected to the eighth pilot valve 17, controlling the forward and reverse conduction functions of the fourth hydraulically controlled check valve 34. When the eighth pilot valve 17 is energized, the fourth hydraulically controlled check valve 34 is conducting in both forward and reverse directions. When the eighth pilot valve 17 is de-energized, the fourth hydraulically controlled check valve 34 can only be forward-biased.

[0065] In this embodiment, the test system further includes a first adjustable flow valve 61 and a second adjustable flow valve 62 for adjusting the flow rates of the first liquid supply circuit 100 and the second liquid supply circuit 200, as well as the speed of the piston rod in the test cylinder 51. The first adjustable flow valve 61 is disposed on the pipeline between the first hydraulic control check valve 31 and the first reversing valve 21, and is used to adjust the flow rate of the first liquid supply circuit 100 and the speed of the piston rod in the test cylinder 51. The second adjustable flow valve 62 is disposed on the pipeline between the second hydraulic control check valve 32 and the second hydraulic control reversing valve 22, and is used to adjust the flow rate of the second liquid supply circuit 200 and the speed of the piston rod in the test cylinder 51.

[0066] In this embodiment, the proportional overflow valve 71 is also connected to a liquid pump. A throttle valve 63 is provided on the pipeline between the proportional overflow valve 71 and the liquid pump. The throttle valve 63 is used to continuously supply liquid to the proportional overflow valve 71. When the loading cylinder 52 is not moving, the proportional overflow valve 71 is always in an overflow state. When the loading cylinder 52 switches actions, the working pressure of the test cylinder 51 can remain stable.

[0067] The testing system provided in this embodiment achieves no-load testing, durability testing, leakage testing, and pressure resistance testing functions by controlling the on / off states of the first pilot valve 10, second pilot valve 11, third pilot valve 12, fourth pilot valve 13, fifth pilot valve 14, sixth pilot valve 15, seventh pilot valve 16, and eighth pilot valve 17. The system can adapt to testing hydraulic cylinders of different diameters by adjusting the first adjustable flow valve 61 and the second adjustable flow valve 62. The working pressure of the tested cylinder 52 can be adjusted by adjusting the working pressure of the proportional relief valve 72.

[0068] In this embodiment, to measure the pressure in the rodless chamber of the test cylinder 51, a first pressure sensor 41 is installed in the pipeline between the rodless chamber of the test cylinder 51 and the first hydraulic check valve 31; to measure the pressure in the rod chamber of the test cylinder 51, a second pressure sensor 42 is installed in the pipeline between the rod chamber of the test cylinder 51 and the second hydraulic check valve 32; to measure the pressure in the rod chamber of the loading cylinder 52, a third pressure sensor 43 is installed in the pipeline between the rod chamber of the loading cylinder 52 and the third hydraulic check valve 33; and to measure the pressure in the rodless chamber of the loading cylinder 52, a fourth pressure sensor 44 is installed in the pipeline between the rodless chamber of the loading cylinder 52 and the fourth hydraulic check valve 34.

[0069] To monitor the displacement of the piston rod of the test cylinder 51, a first displacement sensor 45 is installed on the test cylinder 51; to monitor the displacement of the piston rod of the loading cylinder 52, a second displacement sensor 46 is installed on the loading cylinder.

[0070] In one specific embodiment of the present invention, the piston rod of the test cylinder 51 and the piston rod of the loading cylinder 52 are connected by a connecting member, which is a rigid component capable of transmitting the force of the piston rod in real time; or the piston rod of the test cylinder 51 and the piston rod of the loading cylinder 52 are connected by a slider 81, a third displacement sensor 81 is connected to the slider 81, and the slider 81 and the piston rod of the test cylinder 51 are connected by a first connecting member; the slider 81 and the piston rod of the loading cylinder 52 are connected by a second connecting member; both the first and second connecting members are rigid components capable of transmitting the force in real time.

[0071] The working principle of a hydraulic cylinder testing system according to this embodiment is explained below:

[0072] The working principle of no-load testing is as follows:

[0073] The no-load test includes two actions: extending and retracting the test cylinder 51. These actions are repeated several times according to the test requirements. During both extension and retraction, the loading cylinder 52 does not apply any load to the test cylinder 51; that is, the rodless and rod-side chambers of the loading cylinder 52 are always connected to the liquid tank, and the pressure is 0.

[0074] When the test cylinder 51 extends, liquid sequentially enters the rodless chamber of the test cylinder 51 through the liquid pump, the first hydraulically controlled directional valve 21, and the first hydraulically controlled check valve 31. Liquid in the rod chamber of the test cylinder 51 sequentially enters the liquid tank through the second hydraulically controlled check valve 32 and the second hydraulically controlled directional valve 22. When the test cylinder 51 retracts, liquid in the rodless chamber of the test cylinder 51 sequentially enters the liquid tank through the first hydraulically controlled check valve 31 and the first hydraulically controlled directional valve 21. Simultaneously, liquid in the liquid tank sequentially enters the rod chamber of the test cylinder 51 through the second directional valve 22 and the second hydraulically controlled check valve 32. The operating states of each pilot valve during the no-load test are as follows:

[0075] Table 1 Pilot Valve Status Table for No-Load Test

[0076]

[0077]

[0078] The working principle of durability testing (i.e., loading testing) is as follows:

[0079] The durability test includes two actions: extending and retracting the test cylinder 51. These actions are repeated several times, alternating between extension and retraction, according to the test requirements. During extension and retraction, the loading cylinder 52 applies a load to the test cylinder 51.

[0080] When the test cylinder 51 is extended, liquid sequentially enters the rodless chamber of the test cylinder 51 through the liquid pump, the first hydraulically controlled directional valve 21, and the first hydraulically controlled check valve 31. Liquid in the rod chamber of the test cylinder 51 sequentially enters the liquid tank through the second hydraulically controlled check valve 32 and the second hydraulically controlled directional valve 22. Liquid in the rodless chamber of the loading cylinder 52 sequentially enters the liquid tank through the fourth hydraulically controlled check valve 34, the fourth hydraulically controlled directional valve 24, and the proportional overflow valve 71. Liquid in the liquid tank sequentially enters the rod chamber of the loading cylinder 52 through the third hydraulically controlled directional valve 23 and the third hydraulically controlled check valve 33.

[0081] When the test cylinder 51 is retracted, the liquid in the rodless chamber of the test cylinder 51 enters the liquid tank sequentially through the first hydraulically controlled check valve 31 and the first hydraulically controlled directional valve 21. At the same time, the liquid in the liquid tank enters the rod chamber of the test cylinder 51 sequentially through the second directional valve 22 and the second hydraulically controlled check valve 32. The liquid in the rod chamber of the loading cylinder 52 enters the liquid tank sequentially through the third hydraulically controlled check valve 33, the third hydraulically controlled directional valve 23 and the proportional overflow valve 71. The liquid in the liquid tank enters the rodless chamber of the loading cylinder 52 sequentially through the fourth hydraulically controlled directional valve 24 and the fourth hydraulically controlled check valve 34.

[0082] Table 2. Status of Solenoid Pilot Valve During Loading Test

[0083]

[0084]

[0085] During the test, the working pressure of the test cylinder 51 was adjusted by adjusting the working pressure of the proportional overflow valve 71.

[0086] The working principle of a leak test is as follows:

[0087] This system can perform leakage tests at any position of the hydraulic cylinder.

[0088] The leakage test procedure for the rodless chamber of test cylinder 51 is as follows:

[0089] Step 1: The test cylinder 51 is first extended or retracted to the designated test position under no-load conditions;

[0090] Step 2: After reaching the designated test position, the fourth liquid supply circuit 400 of the rodless chamber of the loading cylinder 52 is cut off through the fourth hydraulic control check valve 34. The rod chamber of the loading cylinder 52 and the rod chamber of the test cylinder 51 are connected to the liquid tank, and the rodless chamber of the test cylinder 51 is connected to the liquid pump. The liquid pump pressure is adjusted to the test pressure, and the working pressure of the proportional overflow valve 71 is adjusted to 0.

[0091] Step 3: De-energize the fifth pilot valve 14 and wait for the rodless chamber of the test cylinder 51 and the rodless chamber of the loading cylinder 52 to rise to the hydraulic pump pressure;

[0092] Step 4: De-energize the first pilot valve 10, and cut off the circuit of the rodless chamber of the test cylinder 51 through the reverse shut-off function of the first hydraulic check valve 31; maintain pressure for a certain period of time as required, and observe the pressure value changes of the first pressure sensor 41 and the fourth pressure sensor 44. If the pressure value does not drop, it indicates no leakage; a slow drop indicates minor leakage; and a rapid drop indicates severe leakage. Here, we assume the test system is intact and leak-free.

[0093] Table 3. Status of Solenoid Pilot Valve During Rodless Chamber Leakage Test

[0094]

[0095]

[0096] The leakage test of the rod chamber of test cylinder 51 is as follows:

[0097] Step 1: The test cylinder 51 is first extended or retracted to the designated test position under no-load conditions;

[0098] Step 2: After reaching the designated test position, the third liquid supply circuit 300 of the rod chamber of the loading cylinder 52 is cut off through the third hydraulic control check valve 33. The rodless chamber of the loading cylinder 52 and the rodless chamber of the test cylinder 51 are connected to the liquid tank. The rod chamber of the test cylinder 51 is connected to the liquid pump. The pressure of the liquid pump is adjusted to the test pressure, and the pressure of the proportional overflow valve 71 is adjusted to 0.

[0099] Step 3: De-energize the sixth pilot valve 15 and wait for the rod chambers of the test cylinder 51 and the loading cylinder 52 to rise to the hydraulic pump pressure;

[0100] Step 4: De-energize the second pilot valve 11. The reverse shut-off function of the second hydraulic check valve 32 cuts off the circuit to the rod chamber of the test cylinder 51. Maintain pressure for a specified time as required, and observe the pressure changes of the second pressure sensor 42 and the third pressure sensor 43. If the pressure does not decrease, it indicates no leakage; a slow decrease indicates minimal leakage; and a rapid decrease indicates severe leakage. Here, we assume the test system is intact and leak-free.

[0101] Table 4. Status of Solenoid Pilot Valve During Rod-Type Chamber Leakage Test

[0102]

[0103]

[0104] The working principle of the pressure resistance test is as follows:

[0105] The pressure test and leakage test are conducted using the same method, but the hydraulic pump pressure needs to be adjusted to 1.5 times the rated pressure of the hydraulic cylinder.

[0106] The working principle of simulating real load is as follows:

[0107] Step 1: Collect data on the changes in load pressure on the hydraulic cylinder at the site;

[0108] Step 2: Adjust the current input to the proportional relief valve 71 in real time according to the change in the load pressure of the on-site hydraulic cylinder, so that the change in the working pressure of the test cylinder 51 is the same as the change in the load pressure of the on-site hydraulic cylinder.

[0109] During testing, the load on the tested cylinder 51 can be changed in real time by supplying a variable current to the proportional relief valve 71, such as a sinusoidal current to the proportional relief valve 71. Real-time pressure data of the hydraulic cylinder during multiple working cycles can be collected under actual operating conditions. The pressure of the proportional relief valve 71 can then be controlled to change in real time based on the collected pressure data, thus better testing the lifespan of the hydraulic cylinder under real-world conditions.

[0110] This invention is a multifunctional hydraulic cylinder testing system composed of a pilot valve, a hydraulically controlled directional valve, a hydraulically controlled check valve, an adjustable flow valve, and a proportional relief valve 71.

[0111] The combination of pilot valves, hydraulically controlled directional valves, hydraulically controlled check valves, throttle valves, and proportional relief valves in the pressure regulating circuits of each liquid supply circuit enables no-load and loaded tests of the test cylinder 51. This invention uses only one proportional relief valve 71 and one liquid pump to achieve the extension and retraction loading actions of the test cylinder 51. The combination of pilot valves, hydraulically controlled directional valves, and hydraulically controlled check valves allows for leakage testing of the piston rod of the test cylinder 51 at any position, meeting the industry's need for multi-position leakage testing.

[0112] The test cylinder 51 with different diameters can be adapted to the test by adjusting the first adjustable flow valve 61 and the second adjustable flow valve 62. The working pressure of the test cylinder 51 is adjusted by adjusting the working pressure of the proportional relief valve 71, and the pressure of the proportional relief valve 71 is controlled to change in real time according to the load pressure of the test cylinder under actual working conditions, so as to realize the simulation of the actual working conditions of the test cylinder 51.

[0113] A second embodiment of the present invention provides a hydraulic cylinder testing method, which is implemented using the hydraulic cylinder testing system described in any of the above claims.

[0114] When performing a no-load test:

[0115] The no-load test includes two actions: extending and retracting the test cylinder 51. These actions are repeated several times according to the test requirements. During both extension and retraction, the loading cylinder 52 does not apply any load to the test cylinder 51; that is, the rodless and rod-side chambers of the loading cylinder 52 are always connected to the liquid tank, and the pressure is 0.

[0116] When the test cylinder 51 extends, liquid sequentially enters the rodless chamber of the test cylinder 51 through the liquid pump, the first hydraulically controlled directional valve 21, and the first hydraulically controlled check valve 31. Liquid in the rod chamber of the test cylinder 51 sequentially enters the liquid tank through the second hydraulically controlled check valve 32 and the second hydraulically controlled directional valve 22. When the test cylinder 51 retracts, liquid in the rodless chamber of the test cylinder 51 sequentially enters the liquid tank through the first hydraulically controlled check valve 31 and the first hydraulically controlled directional valve 21. At the same time, liquid in the liquid tank sequentially enters the rod chamber of the test cylinder 51 through the second directional valve 22 and the second hydraulically controlled check valve 32.

[0117] When conducting durability tests (i.e., load tests):

[0118] The durability test includes two actions: extending and retracting the test cylinder 51. These actions are repeated several times, alternating between extension and retraction, according to the test requirements. During extension and retraction, the loading cylinder 52 applies a load to the test cylinder 51.

[0119] When the test cylinder 51 is extended, liquid sequentially enters the rodless chamber of the test cylinder 51 through the liquid pump, the first hydraulically controlled directional valve 21, and the first hydraulically controlled check valve 31. Liquid in the rod chamber of the test cylinder 51 sequentially enters the liquid tank through the second hydraulically controlled check valve 32 and the second hydraulically controlled directional valve 22. Liquid in the rodless chamber of the loading cylinder 52 sequentially enters the liquid tank through the fourth hydraulically controlled check valve 34, the fourth hydraulically controlled directional valve 24, and the proportional overflow valve 71. Liquid in the liquid tank sequentially enters the rod chamber of the loading cylinder 52 through the third hydraulically controlled directional valve 23 and the third hydraulically controlled check valve 33.

[0120] When the test cylinder 51 is retracted, the liquid in the rodless chamber of the test cylinder 51 enters the liquid tank sequentially through the first hydraulically controlled check valve 31 and the first hydraulically controlled directional valve 21. At the same time, the liquid in the liquid tank enters the rod chamber of the test cylinder 51 sequentially through the second directional valve 22 and the second hydraulically controlled check valve 32. The liquid in the rod chamber of the loading cylinder 52 enters the liquid tank sequentially through the third hydraulically controlled check valve 33, the third hydraulically controlled directional valve 23 and the proportional overflow valve 71. The liquid in the liquid tank enters the rodless chamber of the loading cylinder 52 sequentially through the fourth hydraulically controlled directional valve 24 and the fourth hydraulically controlled check valve 34.

[0121] During the test, the working pressure of the test cylinder 51 was adjusted by adjusting the working pressure of the proportional overflow valve 71.

[0122] When conducting a leak test:

[0123] The leakage test procedure for the rodless chamber of test cylinder 51 is as follows:

[0124] Step 1: The test cylinder 51 is first extended or retracted to the designated test position under no-load conditions;

[0125] Step 2: After reaching the designated test position, the fourth liquid supply circuit 400 of the rodless chamber of the loading cylinder 52 is cut off through the fourth hydraulic control check valve 34. The rod chamber of the loading cylinder 52 and the rod chamber of the test cylinder 51 are connected to the liquid tank, and the rodless chamber of the test cylinder 51 is connected to the liquid pump. The liquid pump pressure is adjusted to the test pressure, and the working pressure of the proportional overflow valve 71 is adjusted to 0.

[0126] Step 3: De-energize the fifth pilot valve 14 and wait for the rodless chamber of the test cylinder 51 and the rodless chamber of the loading cylinder 52 to rise to the hydraulic pump pressure;

[0127] Step 4: De-energize the first pilot valve 10, and cut off the circuit of the rodless chamber of the test cylinder 51 through the reverse shut-off function of the first hydraulic check valve 31; maintain pressure for a certain period of time as required, and observe the pressure value changes of the first pressure sensor 41 and the fourth pressure sensor 44. If the pressure value does not drop, it indicates no leakage; a slow drop indicates minor leakage; and a rapid drop indicates severe leakage. Here, we assume the test system is intact and leak-free.

[0128] The leakage test of the rod chamber of test cylinder 51 is as follows:

[0129] Step 1: The test cylinder 51 is first extended or retracted to the designated test position under no-load conditions;

[0130] Step 2: After reaching the designated test position, the third liquid supply circuit 300 of the rod chamber of the loading cylinder 52 is cut off through the third hydraulic control check valve 33. The rodless chamber of the loading cylinder 52 and the rodless chamber of the test cylinder 51 are connected to the liquid tank. The rod chamber of the test cylinder 51 is connected to the liquid pump. The pressure of the liquid pump is adjusted to the test pressure, and the pressure of the proportional overflow valve 71 is adjusted to 0.

[0131] Step 3: De-energize the sixth pilot valve 15 and wait for the rod chambers of the test cylinder 51 and the loading cylinder 52 to rise to the hydraulic pump pressure;

[0132] Step 4: De-energize the second pilot valve 11. The reverse shut-off function of the second hydraulic check valve 32 cuts off the circuit to the rod chamber of the test cylinder 51. Maintain pressure for a specified time as required, and observe the pressure changes of the second pressure sensor 42 and the third pressure sensor 43. If the pressure does not decrease, it indicates no leakage; a slow decrease indicates minimal leakage; and a rapid decrease indicates severe leakage. Here, we assume the test system is intact and leak-free.

[0133] During the pressure test:

[0134] The pressure test and leakage test are conducted using the same method, but the hydraulic pump pressure needs to be adjusted to 1.5 times the rated pressure of the hydraulic cylinder.

[0135] When simulating real load:

[0136] Step 1: Collect data on the changes in load pressure on the hydraulic cylinder at the site;

[0137] Step 2: Adjust the current input to the proportional relief valve 71 in real time according to the change in the load pressure of the on-site hydraulic cylinder, so that the change in the working pressure of the test cylinder 51 is the same as the change in the load pressure of the on-site hydraulic cylinder.

[0138] During testing, the proportional relief valve 71 can be supplied with a current that changes in real time to make the load on the test cylinder 51 change in real time.

Claims

1. A hydraulic cylinder testing system, characterized in that, The device includes a test cylinder, a loading cylinder, a liquid tank, a liquid pump, and a pressure regulating circuit. The piston rods of the loading cylinder and the test cylinder are connected end-to-end. The rodless chamber of the test cylinder is connected to the liquid tank and the liquid pump to form a first liquid supply circuit. The rod chamber of the test cylinder is connected to the liquid tank and the liquid pump to form a second liquid supply circuit. The rod chamber of the loading cylinder is connected to the liquid tank and the pressure regulating circuit to form a third liquid supply circuit. The rodless chamber of the loading cylinder is connected to the liquid tank and the pressure regulating circuit to form a fourth liquid supply circuit. Each of the first, second, third, and fourth liquid supply circuits is equipped with a hydraulically controlled directional valve and a hydraulically controlled check valve to control the on / off state and liquid flow direction of the corresponding liquid supply circuit, thereby conducting a test on the test cylinder.

2. The hydraulic cylinder testing system according to claim 1, characterized in that, The first liquid supply circuit is equipped with a first hydraulically controlled directional valve and a first hydraulically controlled check valve. The rodless chamber of the test cylinder is connected to the first port of the first hydraulically controlled directional valve via a first pipeline. The second port of the first hydraulically controlled directional valve is connected to the liquid tank. The third port of the first hydraulically controlled directional valve is connected to the liquid pump. The first hydraulically controlled check valve is located on the first pipeline. The second liquid supply circuit is equipped with a second hydraulically controlled directional valve and a second hydraulically controlled check valve. The rod chamber of the test cylinder is connected to the first port of the second hydraulically controlled directional valve via a second pipeline. The second port of the second hydraulically controlled directional valve is connected to the liquid tank. The third port of the second hydraulically controlled directional valve is connected to the liquid pump. The second hydraulically controlled check valve is located on the second pipeline. The liquid supply circuit is equipped with a third hydraulically controlled directional valve and a third hydraulically controlled check valve. The rodless chamber of the loading cylinder is connected to the first interface of the third hydraulically controlled directional valve through a third pipeline. The second interface of the third hydraulically controlled directional valve is connected to the liquid tank. The third interface of the third hydraulically controlled directional valve is connected to the pressure regulating circuit. The third hydraulically controlled check valve is located on the third pipeline. The fourth liquid supply circuit is equipped with a fourth hydraulically controlled directional valve and a fourth hydraulically controlled check valve. The rod chamber of the loading cylinder is connected to the first interface of the fourth hydraulically controlled directional valve through a fourth pipeline. The second interface of the fourth hydraulically controlled directional valve is connected to the liquid tank. The third interface of the fourth hydraulically controlled directional valve is connected to the pressure regulating circuit. The third hydraulically controlled check valve is located on the fourth pipeline.

3. The hydraulic cylinder testing system according to claim 2, characterized in that, A first adjustable flow valve is provided on the first pipeline between the first hydraulic control check valve and the first interface of the first hydraulic control directional valve; a second adjustable flow valve is provided on the second pipeline between the second hydraulic control check valve and the first interface of the second hydraulic control directional valve.

4. The hydraulic cylinder testing system according to claim 2, characterized in that, The hydraulic cylinder testing system further includes a first pilot valve, a second pilot valve, a third pilot valve, a fourth pilot valve, a fifth pilot valve, a sixth pilot valve, a seventh pilot valve, and an eighth pilot valve. The first hydraulically controlled directional valve is connected to the first pilot valve; the second hydraulically controlled directional valve is connected to the second pilot valve; the third hydraulically controlled directional valve is connected to the third pilot valve; the fourth hydraulically controlled directional valve is connected to the fourth pilot valve; the first hydraulically controlled check valve is connected to the fifth pilot valve; the second hydraulically controlled check valve is connected to the sixth pilot valve; the third hydraulically controlled check valve is connected to the seventh pilot valve; and the fourth hydraulically controlled check valve is connected to the eighth pilot valve.

5. The hydraulic cylinder testing system according to claim 1, characterized in that, The pressure regulating circuit is equipped with a proportional relief valve.

6. The hydraulic cylinder testing system according to claim 5, characterized in that, A throttling valve is also provided on the pipeline connecting the liquid pump and the proportional relief valve.

7. The hydraulic cylinder testing system according to claim 2, characterized in that, A first pressure sensor is provided on the first pipeline between the rodless chamber of the test cylinder and the first hydraulic check valve; a second pressure sensor is provided on the second pipeline between the rod chamber of the test cylinder and the second hydraulic check valve; a third pressure sensor is provided on the third pipeline between the rod chamber of the loading cylinder and the third hydraulic check valve; and a fourth pressure sensor is provided on the fourth pipeline between the rodless chamber of the loading cylinder and the fourth hydraulic check valve.

8. The hydraulic cylinder testing system according to claim 1, characterized in that, A slider is connected between the piston rod of the loading cylinder and the piston rod of the test cylinder. The test cylinder is equipped with a first displacement sensor, the loading cylinder is equipped with a second displacement sensor, and the slider is equipped with a third displacement sensor.

9. A test method for a hydraulic cylinder, characterized in that, When performing a no-load test using the hydraulic cylinder testing system as described in any one of claims 1-8, the test includes: Both the rod-side chamber and the rodless chamber of the loading cylinder are connected to the liquid tank; When the test cylinder extends, the rodless chamber of the test cylinder is connected to the liquid pump, and its rod chamber is connected to the liquid tank; when the test cylinder retracts, the rodless chamber of the test cylinder is connected to the liquid tank, and its rod chamber is connected to the liquid pump.

10. A method for testing a hydraulic cylinder, characterized in that, When performing a durability test using the hydraulic cylinder testing system as described in any one of claims 1-8, the test includes: When the test cylinder is extended, the rodless chamber of the test cylinder is connected to the liquid pump, the rod chamber of the test cylinder is connected to the liquid tank, the rodless chamber of the loading cylinder is connected to the pressure regulating circuit, and the rod chamber of the loading cylinder is connected to the liquid tank. When the test cylinder is retracted, the rodless chamber of the test cylinder is connected to the liquid tank, the rod chamber of the test cylinder is connected to the liquid pump, the rod chamber of the loading cylinder is connected to the pressure regulating circuit, and the rodless chamber of the loading cylinder is connected to the liquid tank.

11. A method for testing a hydraulic cylinder, characterized in that, When performing a rodless chamber leakage test on the test cylinder using the hydraulic cylinder testing system as described in any one of claims 1-8, the following steps are included: Both the rod-side chamber and the rodless chamber of the loading cylinder are connected to the liquid tank. The test cylinder can be extended or retracted to the designated test position under no-load conditions. Upon reaching the designated test position, the fourth liquid supply circuit connected to the rodless chamber of the loading cylinder is disconnected. The rod chambers of the loading cylinder and the rod chamber of the test cylinder are both connected to the liquid tank, and the rodless chamber of the test cylinder is connected to the liquid pump. The liquid pump pressure is adjusted to the test pressure, and the working pressure of the pressure adjustment circuit is adjusted to 0. De-energize the hydraulic control check valve in the first liquid supply circuit and wait for both the rodless chamber of the test cylinder and the rodless chamber of the loading cylinder to rise to the pump pressure. De-energize the hydraulic control directional valve in the first liquid supply circuit to cut off the first liquid supply circuit to the rodless chamber of the test cylinder; maintain pressure as required and observe the pressure changes in the rodless chamber of the test cylinder and the rodless chamber of the loading cylinder.

12. A method for testing a hydraulic cylinder, characterized in that, When performing a rodless chamber leakage test on the test cylinder using the hydraulic cylinder testing system as described in any one of claims 1-8, the following steps are included: Collect data on the changes in load pressure on the hydraulic cylinders at the site; The working pressure of the pressure regulating circuit is adjusted according to the changes in the load pressure of the hydraulic cylinder at the site to evaluate the life of the cylinder under test.

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