Test device and test method for a load-sensing variable pump

Abstract

The application relates to a test device and a test method of a load-sensitive variable pump. The test device comprises an oil tank for supplying and recovering oil; a pump inlet interface for connecting a pump inlet of the variable pump and guiding a pump inlet oil path to the oil tank; a pump outlet interface for connecting a pump outlet of the variable pump and guiding a hydraulic oil path to the oil tank through a flow adjusting device and a pressure adjusting device; a pump load feedback interface for connecting a pump load feedback port of the variable pump; an external leakage interface for connecting an external leakage port of the variable pump and guiding an external leakage oil path to the oil tank, wherein a second flow meter for measuring the flow at the external leakage port is arranged in the external leakage oil path; and a reversing valve group for adjusting the test device, so that the variable pump is suitable for an unloading state, a full-displacement state and a load-sensitive variable state. The test device can realize the performance test of the variable pump in the three states simply and conveniently by connecting the variable pump once.

Description

A test apparatus and test method for a load-sensitive variable pump Technical Field

[0001] This invention belongs to the field of hydraulic pump testing technology, specifically relating to a test device and test method for a load-sensitive variable pump. Background Technology

[0002] Load-sensitive variable displacement pumps are widely used in various hydraulic systems because they can simultaneously sense the pressure and flow demands of a hydraulic system and respond correctly to changes in these demands. They provide only the necessary flow to maintain system operation at the required working pressure under the load. As the power actuator of a hydraulic system, the performance indicators of load-sensitive pumps are particularly important for evaluating their performance.

[0003] However, existing Chinese standards for variable displacement pump testing only specify test methods for constant pressure and constant power variable displacement pumps, without specifying test methods for other variable displacement functions. Currently, load-sensitive variable displacement pump tests typically only measure their performance at full displacement, which cannot fully reflect the pump's performance and is not conducive to the application of load-sensitive variable displacement pumps. Summary of the Invention

[0004] In view of this, the present invention provides a test apparatus and test method for a load-sensitive variable pump. By connecting the variable pump to the test apparatus once, tests can be completed under three states: unloading, full displacement, and variable displacement. This solves or at least alleviates one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] To achieve the aforementioned objective, a first aspect of the present invention provides a test apparatus for a load-sensitive variable pump, wherein the test apparatus comprises:

[0006] Oil tank, the oil tank being used for supplying and recovering oil;

[0007] A pump inlet interface is provided for connecting to the pump inlet of the variable pump, and the pump inlet interface leads to the pump inlet oil passage connected to the oil tank.

[0008] A pump outlet interface is provided for connecting to the pump outlet of the variable pump, and the pump outlet interface leads to a hydraulic oil circuit. The hydraulic oil circuit is connected to the oil tank through a flow regulating device and a pressure regulating device. A first pressure gauge for measuring the pressure at the pump outlet interface and a first flow meter for measuring the flow rate at the pump outlet interface are provided in the hydraulic oil circuit.

[0009] A pump load feedback port interface is provided, which is used to connect to the pump load feedback port of the variable pump, and a second pressure gauge for measuring its pressure is provided at the pump load feedback port.

[0010] An external leakage port interface is provided for connecting to the external leakage port of the variable pump, and the external leakage port interface leads to the external leakage oil circuit connected to the oil tank. A second flow meter for measuring the flow rate at the external leakage port interface is provided in the external leakage oil circuit.

[0011] And a reversing valve assembly, which is used to adjust the test apparatus to suit the performance of the variable pump in unloaded state, full displacement state and load-sensitive variable state, respectively.

[0012] Optionally, the test apparatus described above may further include a variable pump drive connector, which is connected to the drive motor of the variable pump. A torque sensor and a speed sensor are provided between the drive motor and the variable pump.

[0013] In the test apparatus described above, optionally:

[0014] The flow regulating device includes a first two-way cartridge valve, a first two-way cartridge valve cover plate, and a two-position four-way directional valve located at the pilot control end of the first two-way cartridge valve. The two-position four-way directional valve is used to control the opening and closing of the first two-way cartridge valve, and the limiting screw of the first two-way cartridge valve cover plate is used to control the opening degree of the first two-way cartridge valve.

[0015] The pressure regulating device includes a second two-way cartridge valve and a second two-way cartridge valve cover plate. The limiting screw of the second two-way cartridge valve cover plate is used to control the opening degree of the second two-way cartridge valve.

[0016] The reversing valve assembly includes a first two-position two-normally closed reversing valve, a second two-position two-normally closed reversing valve, and a two-position two-normally open reversing valve. The first two-position two-normally closed reversing valve is connected upstream of the first two-way cartridge valve and the pump load feedback port interface. The second two-position two-normally closed reversing valve is connected upstream of the second two-way cartridge valve and the pump load feedback port interface. The two-position two-normally open reversing valve is connected to the load feedback port interface and the oil tank.

[0017] In the aforementioned test apparatus, optionally, the oil inlet of the two-position four-way directional valve is connected upstream of the first two-way cartridge valve, and the oil return port of the two-position four-way directional valve is connected to the oil tank.

[0018] In the aforementioned test apparatus, optionally, the oil circuit connecting the first two-position two-normally closed reversing valve to the pump load feedback port interface, the oil circuit connecting the second two-position two-normally closed reversing valve to the pump load feedback port interface, and the oil circuit connecting the two-position two-normally open reversing valve to the pump load feedback port interface are connected in pairs.

[0019] In the aforementioned test apparatus, optionally, the load feedback port interface is connected to an overflow valve leading to the oil tank.

[0020] To achieve the foregoing objectives, a second aspect of the present invention provides a method for testing a load-sensitive variable pump using the testing apparatus as described in any one of the first aspects, wherein the pump inlet of the variable pump is connected to the pump inlet interface, the pump outlet of the variable pump is connected to the pump outlet interface, the pump load feedback port of the variable pump is connected to the pump load feedback port interface, and the external leakage port of the variable pump is connected to the external leakage port interface.

[0021] In the aforementioned method, optionally, during the unloading test, the reversing valve group is de-energized, the flow regulating device is closed, and the pump load feedback port interface is connected to the oil tank to test the performance of the variable pump under different speeds and different unloading pressures.

[0022] Optionally, in the method described above, the directional valve assembly includes a first two-position two-normally closed directional valve, a second two-position two-normally closed directional valve, and a two-position two-normally open directional valve. The first two-position two-normally closed directional valve is connected upstream of the first two-way cartridge valve and to the pump load feedback port interface. The second two-position two-normally closed directional valve is connected upstream of the second two-way cartridge valve and to the pump load feedback port interface. The two-position two-normally open directional valve is connected to the load feedback port interface and the oil tank.

[0023] During the full displacement test, the first two-position two normally closed reversing valve and the second two-position two normally open reversing valve are energized, the connection between the pump load feedback port interface and the oil tank is closed, the pump load feedback port interface is connected to the pump outlet interface through the first two-position two normally closed reversing valve, and the output flow of the pump outlet interface passes through the flow regulating device and the pressure regulating device to test the variable pump according to the fixed displacement pump test method.

[0024] Optionally, in the method described above, the directional valve assembly includes a first two-position two-normally closed directional valve, a second two-position two-normally closed directional valve, and a two-position two-normally open directional valve. The first two-position two-normally closed directional valve is connected upstream of the first two-way cartridge valve and to the pump load feedback port interface. The second two-position two-normally closed directional valve is connected upstream of the second two-way cartridge valve and to the pump load feedback port interface. The two-position two-normally open directional valve is connected to the load feedback port interface and the oil tank.

[0025] During the load-sensitive variable state test, the second normally closed reversing valve and the normally open reversing valve are energized. The connection between the pump load feedback port interface and the oil tank is closed. The pump load feedback port interface is connected to the inlet of the pressure regulating device through the second normally closed reversing valve. The output flow of the pump outlet interface passes through the flow regulating device and the pressure regulating device. The output flow is regulated by the flow regulating device, and the pressure is applied by the flow control device.

[0026] This invention, through the oil circuit setup of the load-sensitive variable pump test device, enables the switching between three states of the variable pump—unloaded, full displacement, and variable displacement—with a single connection between the variable pump and the test device, thereby simplifying and effectively measuring the performance of the variable pump in these three states. Attached Figure Description

[0027] The disclosure of this invention will become more apparent from the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings:

[0028] Figure 1 is a schematic diagram of a test apparatus for the load-sensitive variable pump of the present invention;

[0029] Figure 2 is a schematic diagram of another embodiment of the test device for the load-sensitive variable pump of the present invention;

[0030] Figure 3 is a schematic diagram of the installation and testing principle of the variable pump in the embodiment of the test device in Figure 2.

[0031] Reference numerals: 1-Oil tank; 2-Variable pump; 3-Pump inlet interface; 4-Pump outlet interface; 5-Pump load feedback port interface; 6-External leakage port interface; 7-Pump drive connector; 8-Drive motor; 11-First pressure gauge; 12-Second pressure gauge; 13-First flow meter; 14-Second flow meter; 15-Torque sensor; 16-Speed ​​sensor; 20-Flow regulating device; 21-First two-way cartridge valve; 22-First two-way cartridge valve cover plate; 23-Second two-way cartridge valve; 24-Second two-way cartridge valve cover plate; 25-Two-position four-way directional valve; 26-First two-position two normally closed directional valve; 27-Second two-position two normally closed directional valve; 28-Two-position two normally open directional valve; 29-Relief valve; 30-Pressure regulating device; S-Pump inlet; P-Pump outlet; L-External leakage port; Ls-Pump load feedback port. Detailed Implementation

[0032] Referring to the accompanying drawings and specific embodiments, the structure, composition, features, and advantages of the test apparatus and test method for the load-sensitive variable pump of the present invention will be described below by way of example. However, all descriptions should not be construed as limiting the present invention in any way.

[0033] Furthermore, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the various figures, the present invention still allows for any combination or deletion of these technical features (or their equivalents) without any technical obstacle, and thus these further embodiments according to the present invention should also be considered within the scope of this description.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0035] Figure 1 is a schematic diagram of an embodiment of the test apparatus for the load-sensitive variable pump of the present invention.

[0036] As shown in the embodiment of Figure 1, the test apparatus includes an oil tank 1 for supplying and recovering hydraulic fluid. The apparatus also includes a pump inlet port 3, a pump outlet port 4, a pump load feedback port 5, an external leakage port 6, a flow regulating device 20, a pressure regulating device 30, and a reversing valve assembly. The pump inlet port 3 connects to the oil tank 1 to form and guide the pump inlet oil circuit; the external leakage port 6 connects to the oil tank 1 to form and guide the external leakage oil circuit; and the pump outlet port 4 sequentially connects to the flow regulating device 20, the pressure regulating device 30, and the oil tank 1 to form and guide the hydraulic oil circuit.

[0037] As shown in Figure 1, the test apparatus includes a first pressure gauge 11 and a first flow meter 13 in the hydraulic circuit at the pump outlet interface 4. The first pressure gauge 11 measures the oil pressure at the pump outlet interface 4, and the first flow meter 13 measures the oil flow rate at the pump outlet interface 4. A second pressure gauge 12 is installed at the pump load feedback interface 5 to measure the oil pressure at the pump load feedback interface 5. A second flow meter 14 is installed in the external leakage circuit at the external leakage port interface 6 to measure the oil flow rate at the external leakage port interface 6. The product of the measured flow rate and pressure value is the output power of the variable pump 2. Based on the measured flow rate and pressure value, the pump displacement of the variable pump 2 can be calculated, thereby evaluating the performance of the tested variable pump 2. A database range is formed based on the oil flow rate values ​​measured at the external leakage port L of a large number of variable pumps of the same model. By comparing the oil flow rate value at the external leakage port interface 6 measured by the second flow meter 14, it can be determined whether it is within a reasonable range, thus judging whether the tested variable pump 2 is faulty.

[0038] In an optional embodiment, the flow regulating device 20 includes a first two-way cartridge valve 21, a second two-way cartridge valve cover plate 22, and a two-position four-way directional valve 25. The oil inlet of the two-position four-way directional valve 25 is connected upstream of the first two-way cartridge valve 21, and the pump outlet port 4 is connected to the pilot control end of the first two-way cartridge valve 21. Thus, the hydraulic oil is guided from the pump outlet port 4 to the oil inlet of the first two-way cartridge valve 21, and simultaneously flows through the two-position four-way directional valve 25 to the pilot control end of the first two-way cartridge valve 21. At this time, the oil pressure at both ends of the valve core of the first two-way cartridge valve 21 is the same. Since the contact area between the pilot control end of the valve core and the oil is larger than the contact area between the inlet end and the oil, the oil pressure at the pilot control end of the valve core is greater than the oil pressure at the inlet end. Therefore, the valve core cannot be opened, that is, the first two-way cartridge valve 21 is closed, thereby closing the oil circuit of the pump outlet interface 4.

[0039] When the two-position four-way directional valve 25 is energized, its return port is connected to the oil tank 1, connecting the pilot control end of the first two-way cartridge valve 21 to the oil tank 1. This ensures that the pressure at the pilot control end of the first two-way cartridge valve 21 is the same as that in the oil tank 1. Hydraulic oil is guided into the inlet of the first two-way cartridge valve 21 via the pump outlet port 4. At this point, the hydraulic pressure on the valve core at the inlet is greater than the pressure at its pilot control end, allowing the oil at the inlet to push open the valve core, thus opening the first two-way cartridge valve 21. The valve cover plate 22 of the first two-way cartridge valve has a limiting screw, which controls the opening degree of the first two-way cartridge valve 21 to adjust the flow rate of the hydraulic oil circuit, simulating changes in the hydraulic system load, thereby testing the response performance of the variable pump 2 under test.

[0040] According to the embodiment in Figure 1, the pressure regulating device 30 includes a second two-way cartridge valve 23 and a second two-way cartridge valve cover plate 24. The pilot control end and downstream end of the second two-way cartridge valve 23 are connected to the oil tank 1, and the upstream end of the second two-way cartridge valve 23 is connected to the downstream end of the first two-way cartridge valve 21, thereby guiding the hydraulic oil circuit from the pump outlet interface 4 through the first two-way cartridge valve 21 to the second two-way cartridge valve 23. The second two-way cartridge valve cover plate 24 has a limiting screw, which can control the opening degree of the second two-way cartridge valve 23 to adjust the pressure of the hydraulic oil circuit upstream of it, simulate the load change of the hydraulic system, and thus test the response performance of the variable pump 2 under test.

[0041] The directional valve assembly includes a first two-position two-normally closed directional valve 26, a second two-position two-normally closed directional valve 27, and a two-position two-normally open directional valve 28. The first two-position two-normally closed directional valve 26 is connected upstream of the first two-way cartridge valve 21 and to the pump load feedback port interface 5. When the first two-position two-normally closed directional valve 26 is energized, hydraulic oil is guided from the pump outlet interface 4 through the first two-position two-normally closed directional valve 26 to the pump load feedback port interface 5, forming the full displacement state test oil circuit for the variable pump 2. The second two-position two-normally closed directional valve 27 is connected downstream of the first two-way cartridge valve 21 and to the pump load feedback port interface 5. When the second two-position two-normally closed directional valve 27 is energized, hydraulic oil is guided from the pump outlet interface 4 through the first two-way cartridge valve 21 to the second two-way cartridge valve 23, and simultaneously through the second two-position two-normally closed directional valve 27 to the pump load feedback port interface 5, forming the variable state test oil circuit for the variable pump 2. The two-position two-normally open reversing valve 28 connects the load feedback port interface 5 and the oil tank 1. The oil flowing out of the pump load feedback port interface 5 flows to the oil tank 1 through the two-position two-normally open reversing valve 28, forming the unloading state test oil circuit of the variable pump 2. When the two-position two-normally open reversing valve 28 is energized, the connection between the pump load feedback port interface 5 and the oil tank 1 is closed.

[0042] As can be seen from the embodiment in Figure 1, the oil circuit connecting the first two-position two-normally closed reversing valve 26 to the pump load feedback port interface 5, the oil circuit connecting the second two-position two-normally closed reversing valve 27 to the pump load feedback port interface 5, and the oil circuit connecting the two-position two-normally open reversing valve 28 to the pump load feedback port interface 5 are connected in pairs, making the test device simple in structure. The variable pump 2 can switch between unloaded state, full displacement state and load sensitive variable state by connecting to the test device once.

[0043] Optionally, as shown in the embodiment of Figure 1, the test apparatus is equipped with an overflow valve 29. This overflow valve 29 ensures that the pressure of the test apparatus does not exceed the allowable value during the test, thereby ensuring the safety of the test. The overflow valve 29 connects the first two-position two-normally closed directional valve 26, the second two-position two-normally closed directional valve 27, the load feedback port interface 5, and the oil tank 1. That is, the above-mentioned oil circuits share a single overflow valve 29, making the test apparatus simple in structure and effectively ensuring the safety of the test process under the three states of the variable pump 2.

[0044] It should be noted that the aforementioned reversing valve assembly, flow regulating device 20, pressure regulating device 30, and relief valve 29 can be electrically controlled or manually controlled. That is, the first two-way cartridge valve 21, the first two-way cartridge valve cover plate 22, the second two-way cartridge valve 23, the second two-way cartridge valve cover plate 24, the two-position four-way reversing valve 25, the first two-position two normally closed reversing valve 26, the second two-position two normally closed reversing valve 27, and the two-position two normally open reversing valve 28 can be electrically controlled or manually controlled. In actual testing, they can be operated as needed.

[0045] Figure 2 is a schematic diagram of another embodiment of the test apparatus for the load-sensitive variable pump of the present invention.

[0046] Optionally, in the embodiment shown in FIG2, the test apparatus further includes a variable pump drive connector 7, which is connected to the drive motor 8 of the variable pump 2, and the drive motor 8 drives the variable pump 2 to draw oil from the oil tank 1.

[0047] As can also be seen from the embodiment in Figure 2, a torque sensor 15 and a speed sensor 16 are provided between the drive motor 8 and the variable pump 2 to measure the torque and speed of the drive motor 8, respectively. The speed measurement can test the performance indicators of the variable pump 2 at different speeds, and the product of the measured torque and speed is the input power of the variable pump 2.

[0048] Figure 3 is a schematic diagram of the installation and testing principle of the variable pump in the embodiment of the experimental setup in Figure 2. Compared to Figures 1 and 2, Figure 3 shows the variable pump 2.

[0049] The variable displacement pump 2 can be composed of a pump body and a variable mechanism. The full displacement state is the function achieved by the pump body, while the variable mechanism embodies the functional characteristics of the variable displacement pump 2. The variable displacement pump 2 can be divided into two states: unloaded and operational. Therefore, this invention classifies the test states of the load-sensitive variable displacement pump into three categories: full displacement, unloaded, and load-sensitive variable. Specifically, the basic performance of the pump under test in the full displacement state can be tested according to the relevant standards for hydraulic pumps; the assembly level of the load-sensitive pump can be evaluated by testing its outlet pressure, leakage, and input power in the unloaded state; and the variable performance under the load-sensitive state is tested, including its regulation performance and flow stability under load changes.

[0050] As shown in Figure 3, the pump inlet S of variable pump 2 is connected to pump inlet interface 3 to connect to the pump inlet oil circuit; the pump outlet P of variable pump 2 is connected to pump outlet interface 4 to connect to the hydraulic oil circuit; the pump load feedback port interface 5 of variable pump 2 is connected to pump load feedback port Ls to connect to the oil circuit; and the external leakage port L of variable pump 2 is connected to external leakage port interface 6 to connect to the external leakage oil circuit. The following describes the test methods for the performance of variable pump 2 under various states, in conjunction with this figure:

[0051] Variable pump 2 unloading state test: First two-position two normally closed reversing valve 26, second two-position two normally closed reversing valve 27, two-position two normally open reversing valve 28 and two-position four-way reversing valve 25 are de-energized, and the limit screw of the first two-way cartridge valve cover plate 22 closes the opening of the first two-way cartridge valve 21.

[0052] At the start of the test, hydraulic fluid enters the variable pump 2 from the oil tank 1 through the pump inlet S and is divided into two oil circuits. One circuit is a hydraulic oil circuit that flows from the pump outlet P to the inlet of the first two-way cartridge valve 21, and then through the two-position four-way directional valve 25 to the pilot control end of the first two-way cartridge valve 21. At this time, the hydraulic pressure at the pilot control end of the valve core of the first two-way cartridge valve 21 is greater than the hydraulic pressure at the inlet end, so the valve core cannot be opened, thus the first two-way cartridge valve 21 is closed, and the oil circuit at the pump outlet P is closed. The other circuit flows from the pump load feedback port Ls through the two-position two-normally open directional valve 28 to the oil tank 1.

[0053] The unloading pressure inside the variable pump 2 and the speed of the drive motor 8 are adjusted. The values ​​of the first pressure gauge 11, the second pressure gauge 12, the first flow meter 13, the second flow meter 14, the torque sensor 15, and the speed sensor 16 are measured under different unloading pressures and speeds. Based on the measured values, the input power, output power, efficiency, pump displacement, and pump flow rate of the variable pump 2 under different unloading pressures and speeds are calculated, thereby evaluating the performance of the tested variable pump 2 under unloading conditions.

[0054] Specifically, since the pump outlet P is closed, the pressure value at the pump load feedback port Ls is approximately zero. Conventional variable pump unloading state test calculation methods multiply this pressure value by the flow rate to obtain the output power of the pump load feedback port Ls. This output power is very small and differs significantly from the actual output power because this conventional pump test calculation method ignores the internal losses of the tested variable pump 2. These internal losses include, but are not limited to, frictional waste between internal pump components, pressure loss caused by liquid resistance in the flow channels of internal pump components, and oil churning losses caused by moving parts in the pump's internal oil. The test method of this invention uses the torque value measured by the torque sensor 15, the input power of the tested variable pump 2 obtained by the speed sensor 16, the outlet pressure value of the pump load feedback port Ls measured by the second pressure gauge 12, and the flow rate value of the external leakage port L measured by the second flow meter 14. Through calculation, the actual outlet output power of the tested variable pump 2 at the pump load feedback port Ls and the internal losses of the pump can be obtained, thus determining the assembly level of the tested variable pump 2 and evaluating its performance.

[0055] At the same time, it is determined whether the oil flow rate value at the external leakage port L measured by the second flow meter 14 is within a reasonable range, thereby determining whether the variable pump 2 being measured has malfunctioned.

[0056] Variable pump 2 full displacement state test: The two-position two-normally open reversing valve 28 is energized to close the connection between the pump load feedback port Ls and the oil tank 1; the first two-position two-normally closed reversing valve 26 is energized to connect the hydraulic oil circuit of the pump outlet P to the pump load feedback port Ls; the two-position four-way reversing valve 25 is energized to connect the pilot control end of the first two-way cartridge valve 21 to the oil tank 1, thereby opening the first two-way cartridge valve 21.

[0057] At the start of the test, the oil enters the variable pump 2 from the oil tank 1 through the pump inlet S, and is divided into two oil paths from the pump outlet P. One oil path flows through the first two-way cartridge valve 21 to the second two-way cartridge valve 23, and the other oil path flows through the first two-position two-normally closed reversing valve 26 to the pump load feedback port Ls.

[0058] According to the quantitative pump test method, the opening of the first two-way cartridge valve 21 is adjusted by the limiting screw of the first two-way cartridge valve cover plate 22 to control the oil flow rate, and the opening of the second two-way cartridge valve 23 is adjusted by the limiting screw of the second two-way cartridge valve cover plate 24 to control the oil pressure, simulating the load of the hydraulic system. Under constant load, the values ​​of the first pressure gauge 11, the second pressure gauge 12, the first flow meter 13, the second flow meter 14, the torque sensor 15, and the speed sensor 16 are measured. Based on the measured values, the input power, output power, efficiency, pump displacement, and pump flow rate of the variable pump 2 under constant load are calculated to determine the performance of the tested variable pump 2. At the same time, it is determined whether the oil flow rate value at the external leakage port L measured by the second flow meter 14 is within a reasonable range, thereby determining whether the tested variable pump 2 has malfunctioned.

[0059] Variable state test of variable pump 2: The two-position two-normally open directional valve 28 is energized to close the connection between the pump load feedback port Ls and the oil tank 1; the second two-position two-normally closed directional valve 27 is energized to connect the hydraulic oil circuit downstream of the first two-way cartridge valve 21 to the pump load feedback port Ls; the two-position four-way directional valve 25 is energized to connect the pilot control end of the first two-way cartridge valve 21 to the oil tank 1, thereby opening the first two-way cartridge valve 21.

[0060] At the start of the test, the oil enters the variable pump 2 from the oil tank 1 through the pump inlet S, and then passes through the first two-way cartridge valve 21 from the pump outlet P. It then splits into two paths: one flows to the second two-way cartridge valve 23; the other flows to the pump load feedback port Ls through the second two-position normally closed directional valve 27.

[0061] The opening of the first two-way cartridge valve 21 is adjusted by the limiting screw of the first two-way cartridge valve cover plate 22 to control the oil flow rate, and the opening of the second two-way cartridge valve 23 is adjusted by the limiting screw of the second two-way cartridge valve cover plate 24 to control the oil pressure, thereby simulating the load changes of the hydraulic system. The values ​​of the first pressure gauge 11, the second pressure gauge 12, the first flow meter 13, the second flow meter 14, the torque sensor 15, and the speed sensor 16 are measured. By calculating the input power, output power, efficiency, pump displacement, and pump flow rate of the variable pump 2, the performance changes of the variable pump 2 under different loads are obtained. Simultaneously, it is determined whether the oil flow rate value at the external leakage port L measured by the second flow meter 14 is within a reasonable range, thereby determining whether the tested variable pump 2 has malfunctioned.

[0062] This invention relates to a test apparatus for a load-sensitive variable pump. By coordinating various cartridge valves and directional valves to change the oil circuit connection between the pump outlet P and the pump load feedback port Ls, it integrates the test circuits for the unloaded state, full displacement state, and variable displacement state of the load-sensitive variable pump. This allows the test variable pump 2 to complete tests in all three states with a single connection to the test apparatus. Furthermore, by testing the input power and leakage in the standby state, one can use these parameters as one of the bases for evaluating the performance of the pump under test. Simultaneously, this invention uses the standby input power of the variable pump 2 and the oil flow rate at the external leakage port L to determine whether the variable pump 2 is malfunctioning, thereby evaluating the performance of the variable pump 2.

[0063] The technical scope of this invention is not limited to the contents of the above specification. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the scope of this invention.

Claims

1. A test apparatus for a load-sensitive variable pump, characterized in that, include: Oil tank (1); Pump inlet interface (3); The pump outlet interface (4) is connected to the oil tank (1) via the hydraulic oil circuit through the flow regulating device (20) and the pressure regulating device (30). A first pressure gauge (11) and a first flow meter (13) are installed in the hydraulic oil circuit. The pump load feedback port interface (5) is provided with a second pressure gauge (12). The external leakage port interface (6) is provided with a second flow meter (14) in the external leakage oil circuit. The pump load feedback port interface (5) is provided with a second pressure gauge (12). The external leakage port interface (6) is provided with a second flow meter (14) in the external leakage oil circuit. The pump load feedback port interface (5) is provided with a second pressure gauge (12). The external leakage port interface (6) is provided with a second flow meter (14). ... pump load feedback port interface (5) is provided with a second pressure gauge (13). The pump load feedback port interface (5) is provided with a second pressure gauge (12). The pump load feedback port interface (5) is provided with a second pressure gauge (13). The pump load feedback port interface (5) is provided with a second pressure gauge (14). The pump load feedback port interface (5) is provided with a second pressure gauge (12). The pump load feedback port interface (5) is provided with a second pressure gauge (13). The pump load feedback port interface (5) is provided with a second pressure gauge (14). The section device (30) includes a second two-way cartridge valve (23) and a second two-way cartridge valve cover plate (24); the reversing valve group includes a first two-position two-normally closed reversing valve (26), a second two-position two-normally closed reversing valve (27) and a two-position two-normally open reversing valve (28). The first two-position two-normally closed reversing valve (26) is connected upstream of the first two-way cartridge valve (21) and the pump load feedback port interface (5). The second two-position two-normally closed reversing valve (27) is connected upstream of the second two-way cartridge valve (23) and the pump load feedback port interface (5). The two-position two-normally open reversing valve (28) is connected to the load feedback port interface (5) and the oil tank (1).

2. The test apparatus as described in claim 1, characterized in that, The test apparatus also includes a variable pump drive connector (7), which is connected to the drive motor (8) of the variable pump. A torque sensor (15) and a speed sensor (16) are provided between the drive motor (8) and the variable pump (2).

3. The test apparatus as described in claim 1, characterized in that, The inlet of the two-position four-way directional valve (25) is connected to the upstream of the first two-way cartridge valve (21), and the return port of the two-position four-way directional valve (25) is connected to the oil tank (1).

4. The test apparatus as described in claim 1, characterized in that, The oil circuit connecting the first two-position two-normally closed reversing valve (26) to the pump load feedback port interface (5), the oil circuit connecting the second two-position two-normally closed reversing valve (27) to the pump load feedback port interface (5), and the oil circuit connecting the two-position two-normally open reversing valve (28) to the pump load feedback port interface (5) are connected in pairs.

5. The test apparatus as described in any one of claims 1 to 4, characterized in that, The load feedback port (5) is connected to an overflow valve (29) leading to the oil tank.

6. A method for testing a load-sensitive variable pump using the testing apparatus as described in any one of claims 1 to 5, characterized in that, Connect the pump inlet (S) of the variable pump (2) to the pump inlet interface (3), connect the pump outlet (P) of the variable pump (2) to the pump outlet interface (4), connect the pump load feedback port (Ls) of the variable pump (2) to the pump load feedback port interface (5), and connect the external leakage port (L) of the variable pump (2) to the external leakage port interface (6).

7. The method as described in claim 6, characterized in that, During the unloading test, the reversing valve group is de-energized, the flow regulating device is closed, and the pump load feedback port interface (5) is connected to the oil tank (1) to test the performance of the variable pump (2) under different speeds and different unloading pressures.

8. The method as described in claim 6, characterized in that: During the full displacement test, the first two-position two normally closed reversing valve (26) and the two-position two normally open reversing valve (28) are energized, the connection between the pump load feedback port interface (5) and the oil tank (1) is closed, the pump load feedback port interface (5) is connected to the pump outlet interface (4) through the first two-position two normally closed reversing valve (26), and the output flow of the pump outlet interface (4) passes through the flow regulating device and the pressure regulating device to test the variable pump (2) according to the quantitative pump test method.

9. The method as described in claim 6, characterized in that: During the load-sensitive variable state test, the second normally closed reversing valve (27) and the normally open reversing valve (28) are energized, the connection between the pump load feedback port interface (5) and the oil tank (1) is closed, the pump load feedback port interface (5) is connected to the inlet of the pressure regulating device through the second normally closed reversing valve (27), the pump outlet interface (4) outputs flow through the flow regulating device and the pressure regulating device, the output flow is regulated by the flow regulating device, and the pressure is applied by the flow control device.

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