Electro-hydraulic proportional valve test tool and electro-hydraulic proportional valve test method

Abstract

The application discloses an electro-hydraulic proportional valve testing tool and a testing method of an electro-hydraulic proportional valve. The electro-hydraulic proportional valve testing tool comprises a tool body, a through hole group and a pressure measuring hole group which are arranged on the tool body. The through hole group penetrates through the first surface and the second surface of the tool body, and the through hole group comprises four oil channel holes which correspond to the P, A, B and T oil channels of the electro-hydraulic proportional valve respectively. The pressure measuring hole group comprises three pressure measuring holes which are used for mounting pressure sensors respectively. The electro-hydraulic proportional valve testing tool can collect pressure measuring points of the electro-hydraulic proportional valve, and then can process and analyze the pressure of the measuring points, so that the pressure states of the pilot stage, the main stage and the pressure reducing stage of the electro-hydraulic proportional valve can be judged. The operation state of the electro-hydraulic proportional valve of the steam turbine admission regulating system can be diagnosed in advance, the failure of the steam turbine regulating valve of the nuclear power plant can be effectively reduced, and the reliability of the steam turbine admission regulating system can be improved.

Description

Technical Field

[0001] This invention relates to the field of electro-hydraulic proportional valve testing technology, and in particular to an electro-hydraulic proportional valve testing fixture and a testing method for electro-hydraulic proportional valves. Background Technology

[0002] The operational status of the steam turbine inlet regulating valves in nuclear power plants significantly impacts the plant's power generation and can even lead to serious accidents in the turbine unit. Currently, most 1,000 kW nuclear power units use proportional regulating valves for their steam turbine inlet regulating valves. On-site, these valves have repeatedly exhibited instances of momentary closure followed by reopening, causing fluctuations in unit power output. During testing, abnormal conditions have also occurred, such as the inlet regulating valves slowly closing or even failing to close.

[0003] There are several possible causes for the above-mentioned abnormalities, but they all fall into the category of malfunctions in the electro-hydraulic proportional valve actuator of the steam inlet regulating valve, such as pilot stage jamming, main stage jamming, or pressure reducing stage failure. Due to limited on-site monitoring methods, the exact cause of this phenomenon cannot be determined. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a testing fixture for an electro-hydraulic proportional valve and a testing method for an electro-hydraulic proportional valve.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to provide an electro-hydraulic proportional valve testing fixture for installation on an electro-hydraulic proportional valve, the electro-hydraulic proportional valve testing fixture including a fixture body with a polyhedral structure, a group of through holes and a group of pressure measuring holes opened on the fixture body;

[0006] The through-hole group penetrates the first and second surfaces opposite to the tooling body, and the through-hole group includes four oil passage holes corresponding to the P, T, A, and B oil passages of the electro-hydraulic proportional valve, respectively.

[0007] The pressure measuring hole group includes three pressure measuring holes for installing pressure sensors; the three pressure measuring holes are located on three adjacent sides of the tooling body and are respectively connected to the three oil passage holes corresponding to oil passages P, A, and B.

[0008] Preferably, the second surface of the tooling body is provided with four recesses, each of which is located on the outer periphery of an oil passage hole and communicates with the oil passage hole.

[0009] Preferably, the electro-hydraulic proportional valve testing fixture further includes a sealing ring disposed within the recess.

[0010] Preferably, on the first surface of the tooling body, the centers of the four oil passage holes are connected sequentially to form a rhombus; each oil passage hole corresponds to the midline of one side of the first surface.

[0011] Preferably, the pressure testing hole includes a threaded hole section and an end groove; the end groove is located on the side surface, and the threaded hole section extends into the tooling body and connects to the corresponding oil passage hole.

[0012] Preferably, the electro-hydraulic proportional valve testing fixture further includes a positioning pin hole formed on the first surface of the fixture body.

[0013] Preferably, the electro-hydraulic proportional valve testing fixture further includes a plurality of fastening holes penetrating the first and second surfaces opposite to each other of the fixture body; the plurality of fastening holes are distributed around the periphery of the through-hole group.

[0014] Preferably, the electro-hydraulic proportional valve testing fixture further includes a pressure sensor mounted on the pressure testing port.

[0015] The present invention also provides a test method for an electro-hydraulic proportional valve, comprising using the test fixture described in any of the above claims, the test method comprising the following steps:

[0016] S1. Install the tooling body between the pilot stage and the pressure reducing stage of the electro-hydraulic proportional valve;

[0017] The four oil passage holes on the tooling body are respectively connected to the P, T, A, and B oil passages of the pilot stage and the depressurization stage.

[0018] S2. Install pressure sensors on three sides of the tooling body respectively;

[0019] The three pressure sensors correspond to the P, A, and B oil passages of the electro-hydraulic proportional valve, respectively.

[0020] S3. Fix the electro-hydraulic proportional valve with the tooling body to the integrated block of the hydraulic motor, start the power oil pump, and open the oil supply valve of the hydraulic motor.

[0021] S4. The valve controlling the steam turbine inlet regulating valve opens at the first rate until the opening degree is 100%;

[0022] S5. Control the steam turbine inlet regulating valve to close at a second rate, and obtain the pressure detected by the pressure sensor;

[0023] S6. Based on the pressure detected by the pressure sensor, analyze the pressure change trend of the detected pressure measuring point, and diagnose the status of the main stage and / or pressure reducing stage of the electro-hydraulic proportional valve.

[0024] Preferably, step S1 includes: separating the pilot stage on the electro-hydraulic proportional valve from the pressure reducing stage; inserting a locating pin into the locating pin hole of the tooling body; aligning the tooling body with the locating pin hole on the pilot stage using the locating pin; stacking the tooling body on the pressure reducing stage; stacking the pilot stage on the tooling body; and fastening the tooling body between the pressure reducing stage and the pilot stage using fasteners.

[0025] The electro-hydraulic proportional valve testing fixture of the present invention is used to install on the electro-hydraulic proportional valve. It is connected to the oil passage in the voltage proportional valve through a set oil passage hole. The pressure sensor can collect pressure measurement points at multiple points of the electro-hydraulic proportional valve, and then process and analyze the pressure at the measurement points to determine the pressure status of the pilot stage, main stage, pressure reducing stage, etc. of the electro-hydraulic proportional valve. It can diagnose the operating status of the electro-hydraulic proportional valve in the steam turbine inlet regulating system in advance, provide early warning, and prompt on-site personnel to take action to eliminate and mitigate the faults, effectively reducing the failure of the steam turbine regulating valve in nuclear power plants and improving the reliability of the steam turbine inlet regulating system. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the electro-hydraulic proportional valve testing fixture according to an embodiment of the present invention at an angle;

[0028] Figure 2 This is a schematic diagram of the electro-hydraulic proportional valve testing fixture of one embodiment of the present invention from another angle;

[0029] Figure 3 yes Figure 1 The diagram shows the back structure of the electro-hydraulic proportional valve test fixture.

[0030] Figure 4 yes Figure 1 The diagram shows a longitudinal cross-sectional view of the electro-hydraulic proportional valve testing fixture.

[0031] Figure 5 yes Figure 1 The diagram shows a cross-sectional view of the electro-hydraulic proportional valve testing fixture in the transverse direction. Detailed Implementation

[0032] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figures 1-5As shown, an embodiment of the electro-hydraulic proportional valve testing fixture of the present invention is used to be installed on an electro-hydraulic proportional valve to test the performance of the electro-hydraulic proportional valve. The testing fixture may include a fixture body 10, a group of through holes and a group of pressure measuring holes disposed on the fixture body 10.

[0034] The tooling body 10 has a polyhedral structure, having at least a first surface 11 and a second surface 12 facing away from each other, and multiple side surfaces 13 sequentially adjacent to and connected between the first surface 11 and the second surface 12. Specifically, for Figure 1 The tooling body 10 shown is a hexahedral structure, which has four adjacent sides 13, forming six faces of the hexahedral structure with the first surface 11 and the second surface 12 respectively.

[0035] The tooling body 10 can be made of materials such as 45# (45 steel), Q235, and 0Cr18Ni9.

[0036] The through-hole group is formed on the first surface 11 of the tooling body 10 and extends through the second surface 12, that is, through the first surface 11 and the second surface 12 opposite to the tooling body 10.

[0037] The corresponding electro-hydraulic proportional valve has four oil passages: P, A, B, and T. The through-hole group includes four oil passage holes, which are divided into a first oil passage hole 21, a second oil passage hole 22, a third oil passage hole 23, and a fourth oil passage hole 24. The four oil passage holes correspond one-to-one with the P, A, B, and T oil passages of the electro-hydraulic proportional valve and are arranged at intervals on the tooling body 10.

[0038] On the first surface 11 of the tooling body 10, the centers of four oil passage holes, namely the first oil passage hole 21, the second oil passage hole 22, the fourth oil passage hole 24, and the third oil passage hole 23, are connected in sequence to form a rhombus; the first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23, and the fourth oil passage hole 24 can each correspond to the midline of one side of the first surface 11.

[0039] Typically, an electro-hydraulic proportional valve has a pilot stage (pilot valve), a main stage (main valve), and a pressure reducing stage (pressure reducing valve). The test fixture of the present invention is used to be installed between the pressure reducing stage and the pilot stage of the electro-hydraulic proportional valve. The first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23, and the fourth oil passage hole 24 are respectively connected to the P, A, B, and T oil passages of the pilot stage and the pressure reducing stage.

[0040] The second surface 12 of the tooling body 10 is also provided with four recesses, each recess located on the outer periphery of an oil passage hole and communicating with the oil passage hole. The recesses are used to position the sealing ring, and by accommodating the sealing ring therein, the sealing performance of the tooling body 10 on the electro-hydraulic proportional valve is improved. The four recesses are divided into a first recess 211, a second recess 221, a third recess 231, and a fourth recess 241. The first recess 211, the second recess 221, the third recess 231, and the fourth recess 241 are located on the outer periphery of the first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23, and the fourth oil passage hole 24, respectively, and are communicating with them.

[0041] Corresponding to the recessed platform, the electro-hydraulic proportional valve testing fixture of the present invention may further include a sealing ring (not shown) disposed within the recessed platform. The sealing ring is preferably a fluororubber sealing ring.

[0042] The pressure testing hole group primarily serves as a pressure testing point. By installing pressure sensors on it, the pressure within the channel holes can be detected, allowing for analysis and acquisition of pressure changes or trends in the electro-hydraulic proportional valve. The pressure testing hole group includes three testing holes for mounting pressure sensors; these three holes are located on three adjacent sides of the tooling body and are connected to the three oil passage holes corresponding to oil passages P, A, and B, respectively. For example, the first oil passage hole 21, the second oil passage hole 22, and the third oil passage hole 23... Figure 1 , 2 As shown, the three pressure measuring holes are divided into a first pressure measuring hole 31, a second pressure measuring hole 32, and a third pressure measuring hole 33. The first pressure measuring hole 31 is connected to the first oil passage hole 21, and their length extension directions can be relatively perpendicular. The second pressure measuring hole 32 is connected to the second oil passage hole 22, and their length extension directions can be relatively perpendicular. The third pressure measuring hole 33 is connected to the third oil passage hole 23, and their length extension directions can be relatively perpendicular.

[0043] Of course, depending on the installation requirements and actual settings of the pressure sensor, the pressure measuring hole and the second oil passage hole can be tilted relative to each other at a certain angle, as long as it does not affect the pressure measurement and accuracy.

[0044] refer to Figure 4 and Figure 5 Each pressure testing hole (i.e., the first pressure testing hole 31 to the third pressure testing hole 33) may further include a threaded hole section 301 and an end groove 302; the end groove 302 is located on the side 13 of the tooling body 10, and the threaded hole section 301 extends into the tooling body 10 and connects to the corresponding oil passage hole.

[0045] Furthermore, the electro-hydraulic proportional valve testing fixture of the present invention also includes a locating pin hole 40 formed on the first surface 11 of the fixture body 10. This locating pin hole 40 is a blind hole, meaning it has a certain depth on the first surface 11 of the fixture body 10 and does not need to penetrate the second surface 12. Simultaneously, the locating pin hole 40 is located outside the through-hole assembly and is used to cooperate with the locating pin on the electro-hydraulic proportional valve, serving to position the testing fixture during installation.

[0046] To facilitate the mounting and securing of the test fixture on the electro-hydraulic proportional valve, the test fixture also includes multiple fastening holes 50 for tightening bolts and other fasteners. Each fastening hole 50 penetrates the first surface 11 and the second surface 12 opposite to the fixture body 10. The multiple fastening holes 50 are distributed around the periphery of the through-hole group, for example, as shown in the image. Figure 1-3 The four corners near the tooling body 10 are shown.

[0047] To meet testing requirements, the electro-hydraulic proportional valve testing fixture of the present invention also includes a pressure sensor (not shown) installed on each pressure testing port.

[0048] When the testing fixture is not in use, install dustproof bolts on the pressure test hole to seal it and prevent dust and other impurities from entering the pressure test hole and affecting the pressure measurement.

[0049] The electro-hydraulic proportional valve is tested using the electro-hydraulic proportional valve testing fixture of the present invention, with reference to... Figures 1-5 The test method for this electro-hydraulic proportional valve may include the following steps:

[0050] S1. Install the tooling body 10 between the pilot stage and the pressure reducing stage of the electro-hydraulic proportional valve;

[0051] The four oil passage holes on the tooling body 10 are respectively connected to the P, T, A, and B oil passages of the pilot stage and the depressurization stage, that is: the first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23 and the fourth oil passage hole 24 are respectively connected to the P, A, B and T oil passages of the pilot stage and the depressurization stage.

[0052] The specific operation of step S1 is as follows:

[0053] S1.1 Separate the pilot stage from the pressure reducing stage on the electro-hydraulic proportional valve, insert the locating pin into the locating pin hole of the tooling body 10, align the tooling body 10 with the locating pin on the pilot stage, and stack the tooling body 10 on the pressure reducing stage, that is: stack the tooling body 10 with the first surface 11 with the locating pin facing upward on the pressure reducing stage (the pressure reducing stage is above the main stage of the electro-hydraulic proportional valve), and the first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23 and the fourth oil passage hole 24 are respectively connected to the P, A, B and T oil passages of the pressure reducing stage.

[0054] S1.2. The pilot stage is stacked on the tooling body 10, and the P, A, B and T oil passages on the pilot stage are respectively connected to the first oil passage hole 21, the second oil passage hole 22, the third oil passage hole 23 and the fourth oil passage hole 24 on the tooling body 10.

[0055] S1.3 Secure the tooling body 10 between the pressure reducing stage and the pilot stage using fasteners.

[0056] S2. Install pressure sensors on three sides of the tooling body 10 respectively;

[0057] Among them, the first pressure measuring hole 31, the second pressure measuring hole 32 and the third pressure measuring hole 33 on the three sides are respectively used as pressure measuring points. The three pressure sensors detect the pressure at the three pressure measuring points respectively. The three pressure measuring points also correspond to the P, A and B oil passages of the electro-hydraulic proportional valve respectively.

[0058] S3. Fix the electro-hydraulic proportional valve with tooling body 10 to the integrated block of the oil motor, start the power oil pump, and open the oil supply valve of the oil motor.

[0059] S4. The valve controlling the steam turbine inlet regulating valve opens at the first rate until the opening degree is 100%.

[0060] Alternatively, the first rate may be, but is not limited to, 1.1%, 3.3%, or 21%.

[0061] When the valve opens, the power oil pump drives the power oil through the hydraulic actuator's integrated block to the electro-hydraulic proportional valve. Under the action of the open command, the pilot coil of the electro-hydraulic proportional valve is driven, and the power oil enters the hydraulic actuator cylinder to do work, opening the turbine inlet steam regulating valve.

[0062] S5. Control the steam turbine inlet regulating valve to close at a second rate and obtain the pressure detected by the pressure sensor.

[0063] Alternatively, the second rate may be, but is not limited to, 1.1%, 3.3%, or 21%.

[0064] When the valve is closed, the electro-hydraulic proportional valve, under the action of the close command, drives the pilot coil of the electro-hydraulic proportional valve, and the power oil is discharged from the oil cylinder of the oil motor to the oil tank. Under the action of the oil motor spring, the turbine inlet steam regulating valve is closed.

[0065] S6. Based on the pressure detected by the pressure sensor, analyze the pressure change trend of the detected pressure measuring point, that is, the pressure trend on both sides of the main stage of the electro-hydraulic proportional valve (A and B oil passages), and the pressure after the pressure reducing stage (pressure entering the pilot stage). Diagnose the state of the main stage and / or pressure reducing stage of the electro-hydraulic proportional valve through the above pressure trends.

[0066] For example, the pressure status of the pressure measuring points corresponding to oil passages A and B can reflect the movement status of the main stage of the electro-hydraulic proportional valve, whether there is jamming, and whether the main stage is moving in the direction of oil inlet or outlet.

[0067] It can also diagnose the state of the pressure reducing stage of the electro-hydraulic proportional valve. For example, the pressure measuring point after the pressure reducing stage of the electro-hydraulic proportional valve can reflect the state of the pressure reducing stage. If the pressure after the pressure reducing stage is too small compared to the set pressure at a certain set pressure, it can be determined that the pressure reducing stage is stuck or in other abnormal states.

[0068] The invention will be further illustrated below using the Eaton VICKERS KHDG5V833C270NXVMU1H120 electro-hydraulic proportional valve as an example.

[0069] Test fixtures:

[0070] The test fixtures can be machined using raw materials such as 45#, Q235, and 0Cr18Ni9;

[0071] The tooling body is equipped with four φ5.5 fastening holes, four φ6.0 oil passage holes (P / T / A / B oil passages), and four 9.25*1.78 fluororubber sealing rings are arranged on the recessed platform (φ21 / 1.4) at the four φ6.0 oil passage holes; and one φ4 / 6 locating pin hole.

[0072] One pressure testing hole is arranged on each of the three sides of the tooling body. The threaded hole of the pressure testing hole has a specification of G1 / 4-13 / 16 and a threaded hole section of φ6.0 / 21.7; the end groove is φ21 / 1.

[0073] Test method:

[0074] Loosen the fixing bolts of the pilot stage and pressure reducing stage of the electro-hydraulic proportional valve. Align the locating pin on the test fixture with the locating pin hole of the pilot stage. Place the fixture body between the pressure reducing stage and the pilot stage, and tighten the fixing bolts. Open the dustproof bolts on the side of the test fixture, check that the sealing ring at the thread of the pressure sensor is intact, and screw it into the three pressure testing holes on the three sides. Tighten the seals. During this process, it is essential to prevent foreign objects from entering.

[0075] Fix the electro-hydraulic proportional valve with the test fixture installed on the integrated block of the hydraulic motor, start the power oil pump, open the oil supply valve, and give an enable command signal when the oil pressure reaches 12MPa.

[0076] When a 100% opening command at a certain rate (e.g., 1.1%, 3.3%, 21%) is given on the controller, and the valve is fully opened, a closing command at a certain rate (e.g., 1.1%, 3.3%, 21%) is given. By using three pressure sensor measuring points on the test fixture, the pressure change trends at these three measuring points can be obtained, namely the pressure trends on both sides of the main stage of the electro-hydraulic proportional valve (A, B), and the pressure after the pressure reducing stage of the electro-hydraulic proportional valve (the pressure entering the pilot stage of the electro-hydraulic proportional valve).

[0077] By using the testing fixtures and the above testing methods, the state of the main stage of the electro-hydraulic proportional valve can be diagnosed. For example, the pressure status at measuring points A and B can reflect the movement state of the main stage of the electro-hydraulic proportional valve, whether there is jamming, and whether the main stage is moving in the direction of oil inlet or outlet. The state of the pressure reducing stage of the electro-hydraulic proportional valve can also be diagnosed. For example, the pressure measuring point after the pressure reducing stage of the electro-hydraulic proportional valve can reflect the state of the pressure reducing stage. If the pressure after the pressure reducing stage is too low compared to the set pressure at a certain set pressure, it can be judged that the pressure reducing stage is jammed or has other abnormal conditions.

[0078] Failure of pressure reducing stage in electro-hydraulic proportional valve:

[0079] After the controller issues a 100% opening command (rate 21%), the pilot stage of the electro-hydraulic proportional valve actuates, reaching -100% opening (valve opening direction). The current in the electro-hydraulic proportional valve solenoid coil reaches its maximum value of 3A, but the hydraulic actuator position signal remains unchanged. Inspection revealed that the feedback from the main stage of the electro-hydraulic proportional valve did not change, and the oil pressure after the pressure reducing stage and at ports A and B after the pilot stage remained around 0MPa. It was determined that the cause of the electro-hydraulic proportional valve failure was a failure of the pressure reducing stage, resulting in no oil pressure after the pressure reducing stage.

[0080] Pilot stage failure in electro-hydraulic proportional valves:

[0081] After the controller issues a 100% opening command (rate 21%), the pilot stage of the proportional valve actuates and reaches -100% opening (valve opening direction). The current of the electro-hydraulic proportional valve solenoid coil reaches the maximum value of 3A. Inspection revealed that the oil pressure difference between ports A and B of the electro-hydraulic proportional valve has been around 0MPa (or remains unchanged), indicating that the pilot stage has failed.

[0082] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A test method for an electro-hydraulic proportional valve, characterized in that, An electro-hydraulic proportional valve testing fixture is used. The fixture includes a fixture body with a polyhedral structure, a group of through holes and a group of pressure measuring holes formed on the fixture body. The group of through holes penetrates a first surface and a second surface opposite to each other on the fixture body, and includes four oil passage holes corresponding to the P, A, B, and T oil passages of the electro-hydraulic proportional valve. The group of pressure measuring holes includes three pressure measuring holes for mounting pressure sensors. The three pressure measuring holes are located on three sequentially adjacent sides of the fixture body and are respectively connected to the three oil passage holes corresponding to the P, A, and B oil passages. The testing method includes the following steps: S1. Install the tooling body between the pilot stage and the pressure reducing stage of the electro-hydraulic proportional valve; The four oil passage holes on the tooling body are respectively connected to the P, T, A, and B oil passages of the pilot stage and the depressurization stage. S2. Install pressure sensors on three sides of the tooling body respectively; The three pressure sensors correspond to the P, A, and B oil passages of the electro-hydraulic proportional valve, respectively. S3. Fix the electro-hydraulic proportional valve with the tooling body to the integrated block of the hydraulic motor, start the power oil pump, and open the oil supply valve of the hydraulic motor. S4. The valve controlling the steam turbine inlet regulating valve opens at the first rate until it reaches 100% opening. S5. Control the steam turbine inlet regulating valve to close at a second rate, and obtain the pressure detected by the pressure sensor; S6. Based on the pressure detected by the pressure sensor, analyze the pressure change trend of the detected pressure measuring point, and diagnose the status of the main stage and / or pressure reducing stage of the electro-hydraulic proportional valve.

2. The test method for the electro-hydraulic proportional valve according to claim 1, characterized in that, The electro-hydraulic proportional valve testing fixture also includes a positioning pin hole formed on the first surface of the fixture body. Step S1 includes: separating the pilot stage on the electro-hydraulic proportional valve from the pressure reducing stage; inserting the locating pin into the locating pin hole of the tooling body; aligning the tooling body with the locating pin hole on the pilot stage using the locating pin; stacking the tooling body on the pressure reducing stage; stacking the pilot stage on the tooling body; and fastening the tooling body between the pressure reducing stage and the pilot stage using fasteners.

3. The test method for the electro-hydraulic proportional valve according to claim 1, characterized in that, The second surface of the tooling body is provided with four recessed platforms, each of which is located on the outer periphery of an oil passage hole and is connected to the oil passage hole.

4. The test method for the electro-hydraulic proportional valve according to claim 3, characterized in that, The electro-hydraulic proportional valve testing fixture also includes a sealing ring disposed within the recessed platform.

5. The test method for the electro-hydraulic proportional valve according to claim 1, characterized in that, On the first surface of the tooling body, the centers of the four oil passage holes are connected sequentially to form a rhombus; each oil passage hole corresponds to the midline of one side of the first surface.

6. The test method for the electro-hydraulic proportional valve according to claim 1, characterized in that, The pressure testing hole includes a threaded hole section and an end groove; the end groove is located on the side surface, and the threaded hole section extends into the tooling body and connects to the corresponding oil passage hole.

7. The test method for the electro-hydraulic proportional valve according to any one of claims 1-6, characterized in that, The electro-hydraulic proportional valve testing fixture also includes multiple fastening holes penetrating the first and second surfaces opposite to each other of the fixture body; the multiple fastening holes are distributed around the periphery of the through-hole group.

8. The test method for the electro-hydraulic proportional valve according to any one of claims 1-6, characterized in that, The electro-hydraulic proportional valve testing fixture also includes a pressure sensor installed on the pressure testing port.

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