A hydraulic measuring device and method for measuring the stacking volume of an electro-hydraulic servo valve.

Abstract

This invention discloses a hydraulic measurement device and method for the superposition volume of an electro-hydraulic servo valve. The device includes a measuring fixture and a hydraulic system. The measuring fixture is used to fix the electro-hydraulic servo valve to be tested and to drive the valve core of the electro-hydraulic servo valve to move, thereby obtaining the displacement of the valve core. The hydraulic system includes an oil source and a measuring oil circuit. The oil source includes an oil tank and a hydraulic pump. The hydraulic pump is used to pump hydraulic oil from the oil tank through a pipeline pump from the oil inlet P to the measuring oil circuit, and the hydraulic oil in the measuring oil circuit returns to the oil tank through a pipeline from the oil return port T. The hydraulic measurement device and method for the superposition volume of an electro-hydraulic servo valve provided by this invention uses multiple solenoid valves in conjunction with a throttle valve in its hydraulic system, which facilitates the completion of various operations as needed. It also incorporates structures such as a pressure reducing valve and an accumulator, achieving pressure control through the principle of pressure reduction, which helps improve measurement efficiency and stability and ensures measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of electro-hydraulic servo valve technology, and in particular to a hydraulic measuring device and method for measuring the stacking volume of an electro-hydraulic servo valve. Background Technology

[0002] Electro-hydraulic servo valves are crucial control components in electro-hydraulic servo systems, widely used in high-power, high-response applications such as aerospace, shipbuilding, and robotics. Their manufacturing processes demand high precision and are highly complex, with the measurement of the valve's overlap amount being a significant challenge. The overlap amount of an electro-hydraulic servo valve refers to the axial fit dimension between the working edge of the valve core boss and the valve sleeve bore when the valve core is in the center position. Existing methods for measuring the overlap amount of electro-hydraulic servo valves often suffer from problems such as complex device structures, cumbersome operation, and insufficient measurement accuracy. Summary of the Invention

[0003] To address the problems mentioned in the background section, the present invention provides the following technical solution:

[0004] An electro-hydraulic servo valve stacking volume hydraulic measurement device includes a measuring fixture and a hydraulic system;

[0005] The measuring fixture is used to fix the electro-hydraulic servo valve to be tested and to drive the valve core of the electro-hydraulic servo valve to be tested to move, while obtaining the displacement of the valve core.

[0006] The hydraulic system includes an oil source and a measuring oil circuit;

[0007] The oil source includes an oil tank and a hydraulic pump. The hydraulic pump is used to pump the hydraulic oil in the oil tank from the oil inlet P to the measuring oil circuit through the pipeline pump. The hydraulic oil in the measuring oil circuit returns to the oil tank from the oil return port T through the pipeline.

[0008] In the measuring oil circuit, the oil inlet P is connected to the first solenoid valve through a pipeline and then splits into two branches. One branch is connected to the second solenoid valve, the first throttle valve and the third solenoid valve in parallel through a pipeline and then connected to the AD side inlet of the electro-hydraulic servo valve to be tested. The other branch is connected to the fourth solenoid valve, the second throttle valve and the fifth solenoid valve in parallel through a pipeline and then connected to the BC side inlet of the electro-hydraulic servo valve to be tested.

[0009] The M port of the electro-hydraulic servo valve under test is connected to the sixth solenoid valve and the first flow meter in sequence through a pipeline, and then returns to the oil tank through the return port T. The N port of the electro-hydraulic servo valve under test is connected to the seventh solenoid valve and the second flow meter in sequence through a pipeline, and then returns to the oil tank through the return port T.

[0010] The measuring oil circuit is also equipped with multiple pressure sensors and corresponding pressure measuring connectors.

[0011] In some embodiments, within the measuring oil circuit, the oil inlet P is also connected in sequence to the eighth solenoid valve and the third throttle valve via a pipeline, and then reaches the oil return port T.

[0012] A first accumulator is connected to the rear end of the first solenoid valve, and then connected to the ninth solenoid valve via a pipeline to the return port T.

[0013] In some embodiments, in the oil source, the hydraulic oil in the oil tank passes through the oil outlet pipeline in sequence through the oil suction filter, hydraulic pump, check valve, high pressure filter and manual pressure reducing valve to reach the oil inlet P; the hydraulic oil at the oil return port T passes through the oil return pipeline in sequence through the air cooler and oil return filter to return to the oil tank.

[0014] In some embodiments, in the oil source, a first pressure gauge and a second accumulator are also connected in the oil outlet line between the high-pressure filter and the manual pressure reducing valve, and the oil returns to the oil tank after passing through a pressure sensor and a parallel manual pressure relief valve and a safety pressure valve in sequence.

[0015] In some embodiments, in the oil source, a second pressure gauge is also connected in the oil outlet line between the hydraulic pump and the check valve, and is connected to the return line after passing through an electromagnetic pressure relief valve.

[0016] In some embodiments, the measuring fixture includes a first fixture and a second fixture located at both ends of the electro-hydraulic servo valve to be tested;

[0017] The first fixture includes a base, a slider, a cylinder, a bracket, and a push rod;

[0018] The slider is slidably mounted on the base, the cylinder is used to drive the slider and the push rod to move horizontally as a whole, and the bracket is used to support the push rod;

[0019] The second fixture also includes a base, a slider, a cylinder, a bracket, and a push rod;

[0020] The push rods of the first and second clamps contact the valve core of the electro-hydraulic servo valve under test from the left and right sides, respectively.

[0021] In some embodiments, the first fixture further includes a linear motor mounted on the slider, the output end of the linear motor being connected to the push rod for precisely controlling the linear motion of the push rod, and a force sensor for detecting the pressure of the push rod is also provided at the connection between the linear motor and the push rod.

[0022] The second fixture also includes a spring and a displacement sensor. The spring provides a restoring force to the slider and the push rod, and the displacement sensor accurately detects the displacement of the slider and the push rod.

[0023] Another aspect of the present invention provides a method for hydraulically measuring the stacking volume of an electro-hydraulic servo valve, employing the aforementioned hydraulically measuring device for the stacking volume of an electro-hydraulic servo valve, and comprising the following steps:

[0024] S1. Complete the assembly of the measuring fixture, hydraulic system and the electro-hydraulic servo valve to be tested;

[0025] S2. Adjust each solenoid valve according to the measurement requirements, start the hydraulic pump, and the measuring fixture drives the valve core of the electro-hydraulic servo valve to move, and obtain the displacement of the valve core. The flow rate is obtained through the flow meter to obtain the displacement-flow curve.

[0026] S3. After finding the middle position of the electro-hydraulic servo valve core, complete the measurement of the overlap amount of the electro-hydraulic servo valve.

[0027] In some embodiments, if it is necessary to measure the displacement-flow curve of the AD side of the electro-hydraulic servo valve, then in step S2, the second solenoid valve and the third solenoid valve are opened, and the fourth solenoid valve and the fifth solenoid valve are closed.

[0028] If it is necessary to measure the displacement-flow curve of the BC side of the electro-hydraulic servo valve, then in step S2, the second and third solenoid valves are closed, and the fourth and fifth solenoid valves are opened.

[0029] If it is necessary to simultaneously measure the displacement-flow curves of the AD and BC sides of the electro-hydraulic servo valve, then in step S2, the second, third, fourth, and fifth solenoid valves are opened simultaneously.

[0030] In some embodiments, if it is necessary to find the middle position of the electro-hydraulic servo valve core, in step S2, the fourth solenoid valve is opened, and the second, third and fifth solenoid valves are closed. Oil is supplied to the BC side of the electro-hydraulic servo valve through the second throttle valve. The measuring fixture drives the valve core of the electro-hydraulic servo valve to move, and the displacement and flow rate of the valve core are obtained. The displacement value corresponding to the minimum flow rate is the middle position of the valve core.

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

[0032] The electro-hydraulic servo valve stacking volume hydraulic measurement device and method provided by the present invention uses multiple solenoid valves in conjunction with throttle valves in the hydraulic system, which facilitates the completion of various operations as needed; and is equipped with pressure reducing valves, energy storage devices and other structures, which realize pressure control through the principle of pressure reduction, which helps to improve the efficiency and stability of measurement and ensure measurement accuracy. Attached Figure Description

[0033] Figure 1 A schematic diagram of the measuring oil circuit of the electro-hydraulic servo valve stacking volume hydraulic measuring device provided by the present invention;

[0034] Figure 2A schematic diagram of the oil source for the electro-hydraulic servo valve stacking volume hydraulic measurement device provided by the present invention;

[0035] Figure 3 A schematic diagram of the measuring fixture for the electro-hydraulic servo valve stacking volume hydraulic measuring device provided by the present invention;

[0036] Figure 4 for Figure 3 The corresponding top view;

[0037] Figure 5 This is a one-sided displacement-flow rate curve in a specific embodiment;

[0038] Figure 6 This is a displacement-flow rate curve for the centering process in a specific embodiment. Detailed Implementation

[0039] To make the technical means, creative features, objectives and effects of this invention easier to understand, the following description, in conjunction with the accompanying drawings and specific embodiments, further explains how this invention is implemented.

[0040] This invention provides a hydraulic measuring device for the superposition of electro-hydraulic servo valves, including a measuring fixture and a hydraulic system. The measuring fixture is used to fix the electro-hydraulic servo valve 300 to be tested and to drive the valve core of the electro-hydraulic servo valve 300 to move, while obtaining the displacement of the valve core. The hydraulic system includes an oil source and a measuring oil circuit. The oil source includes an oil tank 10 and a hydraulic pump 7. The hydraulic pump 7 is used to pump the hydraulic oil in the oil tank 10 from the oil inlet P to the measuring oil circuit through a pipeline pump. The hydraulic oil in the measuring oil circuit returns to the oil tank 10 through the oil return port T through a pipeline.

[0041] Reference Figure 1 As shown, in the measuring oil circuit, the oil inlet P is connected to the first solenoid valve 1.1 via a pipeline and then splits into two branches. One branch is connected to the second solenoid valve 1.2, the first throttle valve 2.1 connected in parallel, and the third solenoid valve 1.3 via a pipeline, and then connected to the AD side inlet of the electro-hydraulic servo valve 300 under test. The other branch is connected to the fourth solenoid valve 1.4, the second throttle valve 2.2 connected in parallel, and the fifth solenoid valve 1.5 via a pipeline, and then connected to the BC side inlet of the electro-hydraulic servo valve 300 under test. The M port of the electro-hydraulic servo valve 300 under test is connected to the sixth solenoid valve 1.6 and the first flow meter 3.1 via a pipeline, and then returns to the oil tank 10 through the return port T. The N port of the electro-hydraulic servo valve 300 under test is connected to the seventh solenoid valve 1.7 and the second flow meter 3.2 via a pipeline, and then returns to the oil tank 10 through the return port T. The measuring oil circuit is also equipped with multiple pressure sensors 4.1 and corresponding pressure testing connectors 4.2.

[0042] It is understandable that A, B, C, D, M, and N above all refer to... Figure 1The diagram shows the ports of the electro-hydraulic servo valve 300. Ports A, B, C, and D are inlets; ports A and D are connected as the AD side inlet; ports B and C are connected as the BC side inlet; and ports M and N are outlets.

[0043] Preferably, in the measuring oil circuit, the oil inlet P is also connected to the eighth solenoid valve 1.8 and the third throttle valve 2.3 in sequence through pipelines to reach the oil return port T; the first accumulator 5.1 is also connected to the rear end of the first solenoid valve 1.1, and is connected to the ninth solenoid valve 1.9 through pipelines to reach the oil return port T.

[0044] Further reference Figure 2 As shown, in the oil source, the hydraulic oil in the oil tank 10 passes through the oil outlet pipeline in sequence through the oil suction filter 6, hydraulic pump 7, check valve 13, high pressure filter 15 and manual pressure reducing valve 18 before reaching the oil inlet P; the hydraulic oil at the oil return port T passes through the oil return pipeline in sequence through the air cooler 9 and oil return filter 8 before returning to the oil tank 10.

[0045] Preferably, in the oil source, the oil outlet line between the high-pressure filter 15 and the manual pressure reducing valve 18 is also connected to a first pressure gauge 11.1 and a second accumulator 5.2, and returns to the oil tank 10 after passing through the pressure sensor 4.1 and the parallel manual pressure relief valve 17 and safety pressure valve 16.

[0046] Preferably, in the oil source, a second pressure gauge 11.2 is also connected in the oil outlet line between the hydraulic pump 7 and the check valve 13, and is connected to the return oil line after passing through the electromagnetic pressure relief valve 14.

[0047] In the hydraulic system of this invention, multiple solenoid valves are used in conjunction with a throttle valve to facilitate the completion of various operations as needed; and pressure reducing valves, accumulators and other structures are set up to control the pressure through the principle of pressure reduction, which helps to improve the efficiency and stability of measurement and ensure measurement accuracy.

[0048] Pressure stabilization at the downstream end is achieved through manual pressure reducing valve 18; the second accumulator 5.2 can eliminate some of the pulsating pressure fluctuations of the oil source, and can also store energy when the flow rate is reduced by manual pressure reducing valve 18.

[0049] The third throttle valve 2.3 in the measuring oil circuit can perform oil source testing before testing and can increase oil temperature after pre-start. In addition, during testing, when the valve core of the electro-hydraulic servo valve 300 needs to be closed, the third throttle valve 2.3 helps to prevent the manual pressure reducing valve 18 from working in the minimum working range and ensures that the manual pressure reducing valve 18 works in the linear range.

[0050] Further reference Figure 3 and Figure 4As shown, the measuring fixture includes a first fixture 100 and a second fixture 200 located at both ends of the electro-hydraulic servo valve 300 under test. The first fixture 100 includes a base 101, a slider 102, a cylinder 103, a bracket 104, and a push rod 105. The slider 102 is slidably mounted above the base 101. The cylinder 103 is used to drive the slider 102 and the push rod 105 to move horizontally as a whole. The bracket 104 is used to support the push rod 105. The second fixture 200 also includes a base, a slider, a cylinder, a bracket, and a push rod. The push rods 105 of the first fixture 100 and the second fixture 200 contact the valve core of the electro-hydraulic servo valve 300 under test from the left and right sides, respectively.

[0051] Preferably, the first clamp 100 also includes a linear motor 106, which is mounted on the slider 102. The output end of the linear motor 106 is connected to the push rod 105 for precisely controlling the linear movement of the push rod 105. A force sensor 107 for detecting the pressure of the push rod 105 is also provided at the connection between the linear motor 106 and the push rod 105.

[0052] The second clamp 200 also includes a spring 201 and a displacement sensor 202. The spring 201 is used to provide a restoring force for the slider and the push rod, and the displacement sensor 202 is used to accurately detect the displacement of the slider and the push rod.

[0053] In addition, in specific embodiments, both the first clamp 100 and the second clamp 200 may include two cylinders 103; the driving force of the linear motor 106 can reach 300N, the maximum thrust of a single cylinder 103 can reach 250N, and the two cylinders 103 can reach 500N. The number of springs 201 can also be two, and the spring pressure can be designed to be 200N. Different springs 201 can be selected according to actual conditions to reduce the rebound force.

[0054] Another aspect of the present invention provides a method for hydraulically measuring the stacking volume of an electro-hydraulic servo valve, employing the aforementioned hydraulically measuring device for the stacking volume of an electro-hydraulic servo valve, and comprising the following steps:

[0055] S1. Complete the assembly of the measuring fixture, hydraulic system and the electro-hydraulic servo valve 300 to be tested;

[0056] S2. Adjust each solenoid valve according to the measurement requirements, start the hydraulic pump 7, and the measuring fixture drives the valve core of the electro-hydraulic servo valve 300 to move, and obtain the displacement of the valve core, and obtain the flow rate through the flow meter to obtain the displacement-flow curve.

[0057] S3. After finding the middle position of the valve core of the electro-hydraulic servo valve 300, complete the measurement of the overlap amount of the electro-hydraulic servo valve 300.

[0058] Understandably, before measurement, the cylinders of the first clamp 100 and the second clamp 200 are used to push the push rods on both sides into the initial position, which helps to reduce the time for the equipment to be aligned and reduces the chance of oil leakage.

[0059] If it is necessary to measure the displacement-flow curve of the AD side of the electro-hydraulic servo valve 300, then in step S2, the second solenoid valve 1.2 and the third solenoid valve 1.3 are opened, and the fourth solenoid valve 1.4 and the fifth solenoid valve 1.5 are closed.

[0060] If it is necessary to measure the displacement-flow curve of the BC side of the electro-hydraulic servo valve 300, then in step S2, the second solenoid valve 1.2 and the third solenoid valve 1.3 are closed, and the fourth solenoid valve 1.4 and the fifth solenoid valve 1.5 are opened.

[0061] If it is necessary to simultaneously measure the displacement-flow curves of the AD and BC sides of the electro-hydraulic servo valve 300, then in step S2, the second solenoid valve 1.2, the third solenoid valve 1.3, the fourth solenoid valve 1.4, and the fifth solenoid valve 1.5 are opened simultaneously.

[0062] In one specific embodiment, the curve obtained by unilateral measurement is as follows: Figure 5 As shown, the obtained curves are extended along the two sides respectively. The size of the enclosed portion is used to evaluate the fillet size; the smaller the area, the smaller the fillet. This invention uses multiple solenoid valves to control the oil supply circuit, and the measured curves are helpful for judging the fillet size.

[0063] To locate the center position of the electro-hydraulic servo valve 300, in step S2, open the fourth solenoid valve 1.4 and close the second solenoid valve 1.2, the third solenoid valve 1.3, and the fifth solenoid valve 1.5. Oil is supplied to the BC side of the electro-hydraulic servo valve 300 through the second throttle valve 2.2. Due to the action of the second throttle valve 2.2, the hydraulic flow rate will not exceed the limit value of the second throttle valve 2.2. The measuring fixture moves the valve core of the electro-hydraulic servo valve 300, obtaining the displacement and flow rate of the valve core. The displacement value corresponding to the minimum flow rate is the center position of the valve core. Figure 6 As shown.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hydrodynamic measuring device for electro-hydraulic servo valve stacking, characterized in that, Includes measuring fixtures and hydraulic systems; The measuring fixture is used to fix the electro-hydraulic servo valve (300) to be tested, and to drive the valve core of the electro-hydraulic servo valve (300) to be tested to move, while obtaining the displacement of the valve core. The hydraulic system includes an oil source and a measuring oil circuit; The oil source includes an oil tank (10) and a hydraulic pump (7). The hydraulic pump (7) is used to pump the hydraulic oil in the oil tank (10) from the oil inlet P to the measuring oil circuit through the pipeline pump. The hydraulic oil in the measuring oil circuit returns to the oil tank (10) through the pipeline from the oil return port T. In the measuring oil circuit, the oil inlet P is connected to the first solenoid valve (1.1) through a pipeline and then splits into two branches. One branch is connected to the second solenoid valve (1.2), the first throttle valve (2.1) and the third solenoid valve (1.3) in parallel through a pipeline and then connected to the AD side inlet of the electro-hydraulic servo valve (300) to be tested. The other branch is connected to the fourth solenoid valve (1.4), the second throttle valve (2.2) and the fifth solenoid valve (1.5) in parallel through a pipeline and then connected to the BC side inlet of the electro-hydraulic servo valve (300) to be tested. The M port of the electro-hydraulic servo valve (300) under test is connected to the sixth solenoid valve (1.6) and the first flow meter (3.1) in sequence through a pipeline, and then returns to the oil tank (10) through the return port T. The N port of the electro-hydraulic servo valve (300) under test is connected to the seventh solenoid valve (1.7) and the second flow meter (3.2) in sequence through a pipeline, and then returns to the oil tank (10) through the return port T. The measuring oil circuit is also equipped with multiple pressure sensors (4.1) and corresponding pressure measuring connectors (4.2). In the measuring oil circuit, the oil inlet P is also connected to the eighth solenoid valve (1.8) and the third throttle valve (2.3) in sequence through pipelines before reaching the oil return port T; A first accumulator (5.1) is also connected to the rear end of the first solenoid valve (1.1), and is connected to the ninth solenoid valve (1.9) through a pipeline to reach the return port T.

2. The electro-hydraulic servo valve stacking volume hydraulic measuring device according to claim 1, characterized in that, In the oil source, the hydraulic oil in the oil tank (10) passes through the oil outlet pipeline in sequence through the oil suction filter (6), hydraulic pump (7), check valve (13), high pressure filter (15) and manual pressure reducing valve (18) to reach the oil inlet P; the hydraulic oil at the oil return port T passes through the oil return pipeline in sequence through the air cooler (9) and oil return filter (8) to return to the oil tank (10).

3. The electro-hydraulic servo valve stacking volume hydraulic measuring device according to claim 2, characterized in that, In the oil source, the oil outlet line between the high pressure filter (15) and the manual pressure reducing valve (18) is also connected to the first pressure gauge (11.1) and the second accumulator (5.2), and returns to the oil tank (10) after passing through the pressure sensor (4.1) and the parallel manual pressure relief valve (17) and the safety pressure valve (16).

4. The electro-hydraulic servo valve stacking volume hydraulic measuring device according to claim 2, characterized in that, In the oil source, a second pressure gauge (11.2) is also connected in the oil outlet line between the hydraulic pump (7) and the check valve (13), and is connected to the return oil line after passing through the electromagnetic pressure relief valve (14).

5. The electro-hydraulic servo valve stacking volume hydraulic measuring device according to claim 1, characterized in that, The measuring fixture includes a first fixture (100) and a second fixture (200) located at both ends of the electro-hydraulic servo valve (300) to be tested. The first clamp (100) includes a base (101), a slider (102), a cylinder (103), a bracket (104), and a push rod (105). The slider (102) is slidably mounted above the base (101), the cylinder (103) is used to drive the slider (102) and the push rod (105) to move horizontally as a whole, and the bracket (104) is used to support the push rod (105). The second clamp (200) also includes a base, a slider, a cylinder, a bracket, and a push rod; The push rods (105) of the first clamp (100) and the second clamp (200) respectively contact the valve core of the electro-hydraulic servo valve (300) under test from the left and right sides.

6. The electro-hydraulic servo valve stacking volume hydraulic measuring device according to claim 5, characterized in that, The first fixture (100) also includes a linear motor (106), which is mounted on the slider (102). The output end of the linear motor (106) is connected to the push rod (105) for precisely controlling the linear motion of the push rod (105). A force sensor (107) for detecting the pressure of the push rod (105) is also provided at the connection between the linear motor (106) and the push rod (105). The second clamp (200) also includes a spring (201) and a displacement sensor (202), the spring (201) being used to provide a restoring force for the slider and the push rod, and the displacement sensor (202) being used to accurately detect the displacement of the slider and the push rod.

7. A method for measuring the combined volume of an electro-hydraulic servo valve, characterized in that, The electro-hydraulic servo valve stacking volume hydraulic measurement device according to any one of claims 1-6 includes the following steps: S1. Complete the assembly of the measuring fixture, hydraulic system and the electro-hydraulic servo valve (300) to be tested; S2. According to the measurement requirements, adjust each solenoid valve, start the hydraulic pump (7), and the measuring fixture drives the valve core of the electro-hydraulic servo valve (300) to move, and obtain the displacement of the valve core, and obtain the flow rate through the flow meter to obtain the displacement-flow curve. S3. After finding the middle position of the valve core of the electro-hydraulic servo valve (300), complete the measurement of the overlap of the electro-hydraulic servo valve (300).

8. The electro-hydraulic servo valve stacking volume hydraulic measurement method according to claim 7, characterized in that, If it is necessary to measure the displacement-flow curve of the AD side of the electro-hydraulic servo valve (300), then in step S2, the second solenoid valve (1.2) and the third solenoid valve (1.3) are opened, and the fourth solenoid valve (1.4) and the fifth solenoid valve (1.5) are closed. If it is necessary to measure the displacement-flow curve of the BC side of the electro-hydraulic servo valve (300), then in step S2, the second solenoid valve (1.2) and the third solenoid valve (1.3) are closed, and the fourth solenoid valve (1.4) and the fifth solenoid valve (1.5) are opened. If it is necessary to simultaneously measure the displacement-flow curves of the AD and BC sides of the electro-hydraulic servo valve (300), then in step S2, the second solenoid valve (1.2), the third solenoid valve (1.3), the fourth solenoid valve (1.4) and the fifth solenoid valve (1.5) are opened simultaneously.

9. The electro-hydraulic servo valve stacking volume hydraulic measurement method according to claim 7, characterized in that, If it is necessary to find the middle position of the valve core of the electro-hydraulic servo valve (300), in step S2, the fourth solenoid valve (1.4) is opened, the second solenoid valve (1.2), the third solenoid valve (1.3) and the fifth solenoid valve (1.5) are closed, and oil is supplied to the BC side of the electro-hydraulic servo valve (300) through the second throttle valve (2.2). The measuring fixture drives the valve core of the electro-hydraulic servo valve (300) to move, and obtains the displacement and flow rate of the valve core. The displacement value corresponding to the minimum flow rate is the middle position of the valve core.

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