Large-flow electro-hydraulic servo valve

Abstract

The invention discloses a high-flow electro-hydraulic servo valve which comprises a valve body, a valve rod, a valve rod, a valve rod, a valve rod, a valve rod and a valve rod, wherein a valve cavity, a first mounting port and a second mounting port are formed in the valve body; the valve sleeve is fixedly arranged in the valve cavity, and a first opening and a second opening are formed in the valve sleeve; the valve element is slidably arranged in the valve sleeve and provided with a first sliding column end and a second sliding column end. The displacement sensor is used for detecting the moving stroke of the valve element; the two shaft sleeves are fixedly arranged at the first opening and the second opening correspondingly and slidably arranged outside the first sliding column end and the second sliding column end in a sleeving mode correspondingly, and the two shaft sleeves are matched with the first sliding column end and the second sliding column end correspondingly so as to prevent oil liquid in the channel from leaking; the end face of the second sliding column end is configured to be exposed outside through the second opening and the second installation opening so that the moving stroke of the valve element can be detected from the side where the second installation opening is located. According to the invention, the end face of the second sliding column end can be exposed, and an operator can calibrate the precision of the displacement sensor online.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic control, and particularly to a large-flow electro-hydraulic servo valve. Background Art

[0002] In a hydraulic transmission and control system, a servo valve is a crucial control component, and the performance of the servo valve directly affects the dynamic response and steady-state accuracy of the entire system. By setting a displacement sensor, the movement stroke of the spool in the servo valve can be monitored, thereby providing key information feedback for the closed-loop control of the system to ensure that the spool can accurately stay at the target position, so as to achieve precise flow and pressure regulation. When the accuracy of the displacement sensor is insufficient, the control accuracy of the servo valve will decrease and the dynamic response ability will become worse. Summary of the Invention

[0003] This application aims to solve one of the technical problems in the related art to a certain extent. For this purpose, this application provides a large-flow electro-hydraulic servo valve.

[0004] To achieve the above object, this application adopts the following technical solutions: A large-flow electro-hydraulic servo valve, comprising:

[0005] A valve body, which forms a valve cavity and a first mounting port and a second mounting port at both ends of the valve cavity;

[0006] A valve sleeve, which is fixedly arranged in the valve cavity, and the valve sleeve forms a channel and a first opening and a second opening on both sides of the channel;

[0007] A spool, which is slidably arranged in the channel and has a first sliding column end and a second sliding column end, and the spool is configured to be able to slide relative to the valve sleeve under the drive of the oil flowing into the channel;

[0008] A displacement sensor, which is arranged on the valve body and on the side where the first mounting port and the first opening are located, and the displacement sensor is used to detect the movement stroke of the spool; and,

[0009] Two bushings, the two bushings are respectively fixedly arranged at the first opening and the second opening and are respectively slidably sleeved outside the first sliding column end and the second sliding column end, and the two bushings are respectively matched with the first sliding column end and the second sliding column end to prevent the oil in the channel from leaking;

[0010] Wherein, the end face of the second sliding column end is configured to be able to be exposed outside through the second opening and the second mounting port, so that the movement stroke of the spool can be detected from the side where the second mounting port is located.

[0011] The application of this application has the following beneficial effects: The inventor has found through research that the servo valves in the prior art all seal the valve core in the valve body, so the movement stroke of the valve core can only be detected by the displacement sensor provided by the servo valve. When there is a problem with the displacement sensor (for example, the accuracy is reduced), the above problem cannot be discovered in time. Generally, the problem of the displacement sensor can only be discovered by disassembly and detection after the entire hydraulic control system has obvious problems. The present application sets a shaft sleeve, and uses the shaft sleeve to cooperate with the first sliding column end and the second sliding column end respectively to block the leakage of oil in the channel. The displacement sensor is set on the side where the first installation port is located, so that the end face of the second sliding column end can be exposed to the outside through the second opening and the second installation port. The operator can calibrate and detect the movement stroke of the valve core when the servo valve is in the working state, so as to calibrate the accuracy of the displacement sensor. In addition, since the displacement sensor does not need to withstand oil pressure, a displacement sensor that is not resistant to high pressure can be selected when selecting a displacement sensor, which is lower in cost.

[0012] Optionally, the large-flow electro-hydraulic servo valve further includes an end cover, which is closed at the second mounting port; the end cover is detachably disposed on the valve body; or, the end cover includes a main body portion fixedly disposed on the valve body and a disassembly portion detachably disposed on the main body portion.

[0013] Optionally, the displacement sensor includes a shell, a detection coil disposed in the shell, and an iron core extending from the shell, the iron core is fixedly connected to the first sliding column end, and the detection coil is used to detect the movement of the iron core to obtain the movement stroke of the valve core.

[0014] Optionally, the iron core is provided with an external thread, the first sliding column end is provided with an internal thread, and the iron core is threadedly connected to the first sliding column end.

[0015] Optionally, a first locking nut is threadedly connected to the iron core, and the first locking nut abuts against the first slide post end after the iron core is tightened on the first slide post end.

[0016] Optionally, the large-flow electro-hydraulic servo valve further includes a sensor mounting seat, the sensor mounting seat is fixedly disposed at the first mounting port, and the sensor mounting seat is provided with a threaded hole, and the displacement sensor is threadably connected to the sensor mounting seat through the housing.

[0017] Optionally, a second locking nut is threadedly connected to the shell, and the second locking nut abuts against the sensor mounting seat after the shell is tightened on the sensor mounting seat.

[0018] Optionally, the spool further includes a main body shaft located between the first slide column end and the second slide column end. A first shoulder continuous with the first slide column end and a second shoulder continuous with the second slide column end are formed on the main body shaft. The outer diameter of the first shoulder is larger than that of the first slide column end to form a first control surface therebetween. The inner wall of the channel, the outer surface of the first slide column end, the first control surface, and the inner end surface of one of the bushings cooperate to enclose a first oil chamber. The valve sleeve is provided with a first control oil flow passage communicating with the first oil chamber. The outer diameter of the second shoulder is larger than that of the second slide column end to form a second control surface therebetween. The inner wall of the channel, the outer surface of the second slide column end, the second control surface, and the inner end surface of the other bushing cooperate to enclose a second oil chamber. The valve sleeve is provided with a second control oil flow passage communicating with the second oil chamber.

[0019] Optionally, the ratio of the outer diameter of the first slide column end to the outer diameter of the first shoulder is a selected value between 0.5 and 0.6. The ratio of the outer diameter of the second slide column end to the outer diameter of the second shoulder is a selected value between 0.5 and 0.6.

[0020] Optionally, the bushing includes a first annular section, a second annular section with a diameter smaller than that of the first annular section, and a transition section located between the first annular section and the second annular section. The transition section has a guiding inclined surface. The second annular section and the transition section on one of the bushings are arranged corresponding to the first control oil flow passage to guide the control oil to flow to the first control surface. The second annular section and the transition section on the other bushing are arranged corresponding to the second control oil flow passage to guide the control oil to flow to the second control surface.

[0021] These features and advantages of the present application will be disclosed in detail in the following specific embodiments and the accompanying drawings. The best embodiments or means of the present application will be shown in detail in combination with the drawings, but it is not a limitation to the technical solution of the present application. In addition, these features, elements, and components appear in multiple in each of the following texts and drawings, and different symbols or numbers are marked for convenience of representation, but all represent components with the same or similar structures or functions. Description of the Drawings

[0022] The present application will be further described below with reference to the accompanying drawings:

[0023] Figure 1 It is a schematic structural diagram of a large-flow electro-hydraulic servo valve provided by an embodiment of the present application;

[0024] Figure 2 It is an exploded view of the large-flow electro-hydraulic servo valve;

[0025] Figure 3Explosion diagram of the large-flow electro-hydraulic servo valve from another perspective;

[0026] Figure 4 Cross-sectional view of the large-flow electro-hydraulic servo valve;

[0027] Figure 5 For Figure 4 Enlarged schematic diagram of part A in;

[0028] Figure 6 For Figure 4 Enlarged schematic diagram of part B in;

[0029] Figure 7 For Figure 4 Enlarged schematic diagram of part C in;

[0030] Figure 8 Structural schematic diagram of the bushing;

[0031] Figure 9 Cross-sectional view of the valve body and the spool;

[0032] Figure 10 Cross-sectional view after the spool moves to the right relative to the valve body;

[0033] Figure 11 Cross-sectional view after the spool moves to the left relative to the valve body.

[0034] Wherein, 1. Valve body; 10. Valve cavity; 100. First mounting port; 101. Second mounting port; 2. Valve sleeve; 20. Channel; 200. First opening; 201. Second opening; 21. First control oil flow channel; 22. Second control oil flow channel; 23. First oil supply flow channel; 24. Second oil supply flow channel; 25. First load flow channel; 26. Second load flow channel; 27. Oil return flow channel; 3. Spool; 30. Main shaft; 31. First slide column end; 32. Second slide column end; 33. First shoulder; 330. First control surface; 34. Second shoulder; 340. Second control surface; 35. Third shoulder; 36. Fourth shoulder; 37. First oil cavity; 38. Second oil cavity; 4. Displacement sensor; 40. Housing; 41. Detection coil; 42. Iron core; 43. First locking nut; 44. Second locking screw; 5. Bushing; 50. First annular section; 51. Second annular section; 52. Transition section; 6. End cover; 60. Body part; 61. Dismantling part; 7. Sensor mounting seat. Figure 9 And Figure 10 The arrow direction in indicates the oil flow direction. Specific implementation manner

[0035] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments based on the embodiments are intended to be used to explain the present application and cannot be understood as limiting the present application.

[0036] References to "one embodiment" or "an example" or "an example" in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment disclosed in the present application. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0037] After research, the inventor found that the servo valves in the prior art all seal the valve core in the valve body, so the movement of the valve core can only be detected by the displacement sensor provided by the servo valve. When there is a problem with the displacement sensor (for example, the accuracy is reduced), the problem cannot be discovered in time. Generally, the problem of the displacement sensor can only be discovered by disassembly and detection after the entire hydraulic control system has obvious problems. To this end, this embodiment provides a large flow electro-hydraulic servo valve, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the large flow electro-hydraulic servo valve comprises a valve body 1, a valve sleeve 2, a valve core 3, a displacement sensor 4 and a shaft sleeve 5. The valve body 1 is formed with a valve cavity 10 and a first mounting port 100 and a second mounting port 101 located at both ends of the valve cavity 10. The valve sleeve 2 is fixedly arranged in the valve cavity 10, and the valve sleeve 2 is formed with a channel 20 and a first opening 200 and a second opening 201 located at both sides of the channel 20. The valve core 3 is slidably arranged in the channel 20 and has a first sliding column end 31 and a second sliding column end 32. The valve core 3 is configured to be able to slide relative to the valve sleeve 2 under the drive of the oil flowing into the channel 20. It is easy to understand that the valve sleeve 2 can be assembled into the valve cavity 10 through the first mounting port 100 or the second mounting port 101, and the valve core 3 can be assembled into the channel 20 through the first opening 200 or the second opening 201. The displacement sensor 4 is arranged in the valve body 1 and is located on the side where the first mounting port 100 and the first opening 200 are located. The displacement sensor 4 is used to detect the movement stroke of the valve core 3. That is, when the valve core 3 slides relative to the valve sleeve 2 under the push of the oil, the displacement sensor 4 can detect the movement stroke of the valve core 3 . Specifically, the displacement sensor 4 can detect the sliding direction and sliding distance of the valve core 3 .

[0038] There are two bushings 5 in this embodiment. The two bushings 5 are respectively fixedly arranged at the first opening 200 and the second opening 201 and are respectively sleeved outside the first slide post end 31 and the second slide post end 32 in a sliding manner. The two bushings 5 are respectively matched with the first slide post end 31 and the second slide post end 32 to block the leakage of the oil fluid in the channel 20. Among them, the end face of the second slide post end 32 is configured to be able to be exposed outside through the second opening 201 and the second installation port 101, so that the moving stroke of the spool 3 can be detected from the side where the second installation port 101 is located. In this application, by arranging the bushing 5, the bushing 5 is respectively matched with the first slide post end 31 and the second slide post end 32 to block the leakage of the oil fluid in the channel 20. The displacement sensor 4 is arranged on the side where the first installation port 100 is located. In this way, the end face of the second slide post end 32 can be exposed outside through the second opening 201 and the second installation port 101. The operator can calibrate and detect the moving stroke of the spool 3 when the servo valve is in the working state, so as to calibrate the accuracy of the displacement sensor 4. In addition, since the displacement sensor 4 does not need to bear the oil pressure, a displacement sensor 4 that is not resistant to high pressure can be selected when selecting the displacement sensor 4, and the cost is lower.

[0039] Furthermore, the large-flow electro-hydraulic servo valve provided in this embodiment further includes an end cover 6, and the end cover 6 is closed at the second installation port 101. By arranging the end cover 6, the second installation port 101 can be closed to prevent external dust and other sundries from entering the valve cavity 10. Of course, in order to realize the detection of the moving stroke of the end face of the second slide post end 32, the end cover 6 in this embodiment includes a body part 60 fixedly arranged on the valve body 1 and a disassembly part 61 detachably arranged on the body part 60. Specifically, the body part 60 is tightly and fixedly connected into the second installation port 101. The body part 60 is provided with a threaded hole, and the disassembly part 61 is a stud threadedly connected to the threaded hole. When it is necessary to calibrate the accuracy of the displacement sensor 4, the disassembly part 61 can be removed, and the end face of the second slide post end 32 can be exposed outside through the threaded hole on the body part 60, so that a calibration instrument can be used to perform a stroke detection on it, and the calibration of the displacement sensor 4 can be realized. Of course, in other alternative embodiments, the end cover 6 can also be an integral structure. Correspondingly, the end cover 6 is detachably arranged relative to the valve body 1 as a whole. In this way, when it is necessary to calibrate the accuracy of the displacement sensor 4, the end cover 6 can be detached relative to the valve body 1 as a whole, so that the second installation port 101 is completely opened. In addition, in other alternative embodiments, the disassembly part 61 can also be designed as a detachable connection method such as snap connection or plug connection relative to the body part 60, which will not be elaborated here.

[0040] It is easy to understand that according to the calibration operation requirements, the calibration instrument refers to a displacement detection instrument whose accuracy is at least one order of magnitude higher than that of the displacement sensor 4 applied in the large-flow electro-hydraulic servo valve.

[0041] As described above, when the large-flow electro-hydraulic servo valve provided in this embodiment is adopted, since the displacement sensor 4 does not need to bear the oil pressure, a displacement sensor 4 that is not resistant to high pressure can be selected when choosing the displacement sensor 4, and the cost is lower. Specifically in this embodiment, the displacement sensor 4 is a linear variable differential transformer (LVDT - Linear Variable Displacement Transducer), which belongs to a linear displacement sensor 4. It includes a housing 40, a detection coil 41 arranged in the housing 40, and an iron core 42 extending from the housing 40. The iron core 42 is fixedly connected to the first slide post end 31. The detection coil 41 is used to detect the movement of the iron core 42 to obtain the movement stroke of the spool 3. The detection coil 41 includes a primary coil and two secondary coils. When the iron core 42 is in the middle position, the induced electromotive forces generated by the two secondary coils are equal, and thus the output voltage is zero. When the iron core 42 moves inside the secondary coil and deviates from the central position, the induced electromotive forces generated by the two secondary coils are not equal, and there will be a voltage output. The magnitude of the output voltage depends on the magnitude of the displacement. The voltage output by the LVDT is the difference between the voltages of the two secondary coils, and the output voltage value is linearly related to the displacement of the iron core 42.

[0042] Of course, other sensors such as magnetoresistive sensors, Hall effect sensors, and inductive sensors that can detect the movement stroke of the spool 3 can also be used.

[0043] Furthermore, the connection firmness between the iron core 42 and the first slide post end 31 will affect the detection accuracy of the displacement sensor 4. For this reason, as shown in Figure 2 、 Figure 4 and Figure 7 In this embodiment, the iron core 42 is provided with an external thread, and the first slide post end 31 is provided with an internal thread. The iron core 42 is threadedly connected to the first slide post end 31. In addition, a first locking nut 43 is threadedly connected to the iron core 42 in this embodiment, and the first locking nut 43 abuts against the first slide post end 31 after the iron core 42 is tightened to the first slide post end 31. That is, a first locking nut 43 is pre-tightened on the iron core 42, and then the iron core 42 is threadedly connected to the first slide post end 31. After that, by screwing the first locking nut 43, the first locking nut 43 can be tightened against the end cover 6. The first locking nut 43 can improve the axial stability of the iron core 42 relative to the first slide post end 31, reduce the influence of working vibration on the connection stability between the iron core 42 and the first slide post end 31, and prevent the iron core 42 from loosening relative to the first slide post end 31. Thereby, the measurement accuracy of the displacement sensor 4 can be improved, and the working reliability of the large-flow electro-hydraulic servo valve can be enhanced.

[0044] Further, the large-flow electro-hydraulic servo valve provided in this embodiment further includes a sensor mounting seat 7. The sensor mounting seat 7 is fixedly arranged at the first mounting port 100, and the sensor mounting seat 7 is provided with a threaded hole. The displacement sensor 4 is threadedly connected to the sensor mounting seat 7 through the housing 40. That is, the housing 40 of the displacement sensor 4 is provided with an external thread, and the housing 40 can be screwed into the threaded hole of the sensor mounting seat 7. In addition, a second locking nut is threadedly connected to the housing 40, and the second locking nut abuts against the sensor mounting seat 7 after the housing 40 is tightened on the sensor mounting seat 7. During assembly, a second locking nut is pre-screwed on the housing 40, and then the housing 40 is threadedly connected to the sensor mounting seat 7. After that, the second locking nut can be tightened against the sensor mounting seat 7 by screwing the second locking nut. The second locking nut can improve the axial stability of the housing 40 relative to the sensor mounting seat 7, reduce the influence of working vibration on the connection stability between the housing 40 and the sensor mounting seat 7, and prevent the housing 40 from loosening relative to the sensor mounting seat 7. Thereby, the measurement accuracy of the displacement sensor 4 can be improved, and the working reliability of the large-flow electro-hydraulic servo valve can be enhanced.

[0045] As understood by those skilled in the art, the dynamic characteristics of the servo valve (mainly including response speed and stability) have a certain correlation with the diameter size of the spool 3. Generally, the dynamic characteristics of the servo valve are inversely proportional to the diameter of the spool 3. However, if the diameter size of the spool 3 is designed to be smaller at the same time, it will cause the oil flow to be restricted and cannot be applied to the large-flow electro-hydraulic servo valve. Therefore, in this embodiment, by designing the structure of the spool 3, the dynamic characteristics of the servo valve and the large-flow requirement can be taken into account. Combining Figure 2 、 Figure 4 、 Figure 5 and Figure 6 shown, the spool 3 in this embodiment further includes a main shaft 30 located between the first slide column end 31 and the second slide column end 32. A first shoulder 33 continuous with the first slide column end 31 and a second shoulder 34 continuous with the second slide column end 32 are formed on the main shaft 30. The outer diameter size of the first shoulder 33 is larger than the outer diameter size of the first slide column end 31 to form a first control surface 330 therebetween. The inner wall of the passage 20, the outer surface of the first slide column end 31, the first control surface 330 and the inner end surface of a bushing 5 cooperate to enclose a first oil chamber 37. The valve sleeve 2 is provided with a first control oil flow passage 21 communicating with the first oil chamber 37. Thus, when the control oil flows into the first oil chamber 37 from the first control oil flow passage 21, the control oil will exert pressure on the first control surface 330.

[0046] Similarly, the outer diameter of the second shoulder 34 in this embodiment is larger than the outer diameter of the second slide end 32 to form a second control surface 340 therebetween. The inner wall of the channel 20, the outer surface of the second slide end 32, the second control surface 340, and the inner end surface of another bushing 5 cooperate to enclose and form a second oil chamber 38. The valve sleeve 2 is provided with a second control oil flow passage 22 communicating with the second oil chamber 38. Thus, when the control oil flows into the second oil chamber 38 from the second control oil flow passage 22, the control oil will exert pressure on the second control surface 340. When the pressure on the first control surface 330 is greater than the pressure on the second control surface 340, the valve core 3 will slide to the right; when the pressure on the first control surface 330 is less than the pressure on the second control surface 340, the valve core 3 will slide to the left.

[0047] Through the above structural design, the area sizes of the first control surface 330 and the second control surface 340 can be designed to be smaller, so that better dynamic characteristics can be obtained. At the same time, the diameter sizes of parts such as the first slide end 31, the second slide end 32, the first shoulder 33, and the second shoulder 34 do not need to be designed to be smaller, which can meet the requirements of large-flow oil. In addition, since the diameter sizes of parts such as the first slide end 31, the second slide end 32, the first shoulder 33, and the second shoulder 34 do not need to be designed to be smaller, the overall strength of the valve core 3 can be ensured.

[0048] Further, the ratio of the area of the first control surface 330 to the area of the longitudinal section of the first shoulder 33 in this embodiment is 0.502. Similarly, the ratio of the area of the second control surface 340 to the area of the longitudinal section of the second shoulder 34 is also 0.502. Through experimental analysis, when the ratio of the area of the first control surface 330 to the area of the longitudinal section of the first shoulder 33 is a selected value between 0.5 and 0.6, and the ratio of the area of the second control surface 340 to the area of the longitudinal section of the second shoulder 34 is a selected value between 0.5 and 0.6, the large-flow electro-hydraulic servo valve can have better dynamic characteristics.

[0049] As Figure 5 and Figure 8 shown, the bushing 5 in this embodiment includes a first annular section 50, a second annular section 51, and a transition section 52 located between the first annular section 50 and the second annular section 51. Among them, the diameter size of the second annular section 51 is smaller than the diameter size of the first annular section 50. Correspondingly, the transition section 52 has a guiding inclined surface. The second annular section 51 and the transition section 52 on one bushing 5 are correspondingly arranged with the first control oil flow passage 21 to guide the control oil to flow towards the first control surface 330. The second annular section 51 and the transition section 52 on the other bushing 5 are correspondingly arranged with the second control oil flow passage 22 to guide the control oil to flow towards the second control surface 340. Through the above structural design, the control oil can flow towards the first control surface 330 and the second control surface 340 more quickly.

[0050] Combined with Figure 2 、 Figure 3 and Figure 9 As shown, the spool 3 in this embodiment further includes a third shoulder section and a fourth shoulder section located between the first shoulder section and the second shoulder section. The two sides of the third shoulder section and the two sides of the fourth shoulder section respectively form the spool working edges. The inner wall of the valve sleeve 2 in this embodiment is formed with valve sleeve working edges corresponding one by one to the four spool working edges. When the spool 3 slides relative to the valve sleeve 2, the spool working edges switch states between contact and separation relative to the valve sleeve working edges, realizing the flow control of the oil fluid and the dynamic regulation of the pressure drop.

[0051] In addition to the first control oil flow passage 21 and the second control oil flow passage 22, the valve sleeve 2 in this embodiment is further provided with a first oil supply flow passage 23, a first load flow passage 25, an oil return flow passage 27, a second load flow passage 26, and a second oil supply flow passage 24 that are sequentially and spaced apart along the axial direction.

[0052] This large-flow electro-hydraulic servo valve further includes a pilot valve 8 disposed outside the valve body 1, and the movement of the spool 3 can be controlled through the pilot valve 8. It is easy to understand that the structure of the pilot valve 8, its connection method with the valve body 1, the corresponding working principle, etc. are prior arts and will not be elaborated here.

[0053] Combined with Figure 10 and Figure 11 As shown, the working process of this large-flow electro-hydraulic servo valve provided in this embodiment during application is described as follows: After receiving an instruction from an external control unit, the pilot valve control oil can flow into the first oil chamber 37 and the second oil chamber 38 respectively from the first control oil flow passage 21 and the second control oil flow passage 22 on the valve sleeve 2, and the control oil acts on the first control surface 330 and the second control surface 340 respectively. When the control oil pressure applied to the first control surface 330 is relatively large, the spool 3 can be pushed to slide rightward relative to the valve sleeve 2 (taking the left-right direction shown in Figure 9 as an example). The state shown in Figure 10 is obtained. In this way, the high-pressure oil fluid flows in from the first oil supply flow passage 23, flows through the adjacent valve sleeve working edge and the first load flow passage 25, and finally flows into the high-pressure chamber of the external load actuator. At the same time, the oil fluid in the low-pressure chamber of the load actuator flows through the second load flow passage 26, the adjacent valve sleeve working edge and the oil return flow passage 27 in sequence, and finally flows back to the fuel tank.

[0054] Similarly, when the control oil pressure applied to the second control surface 340 is relatively large, the spool 3 can be pushed to slide leftward relative to the valve sleeve 2 (taking the left-right direction shown in Figure 9 as an example). The state shown in Figure 11The state shown. In this way, the high-pressure hydraulic oil flows into from the second oil supply passage 24, flows through the adjacent working edge of the valve sleeve and the second load passage 26, and finally flows into the high-pressure cavity of the external load actuator. At the same time, the hydraulic oil in the low-pressure cavity of the load actuator flows through the first load passage 25, the adjacent working edge of the valve sleeve and the oil return passage 27 in sequence, and finally flows back to the fuel tank.

[0055] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that the present application includes but is not limited to the content described in the drawings and the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present application will be included in the scope of the claims.

Claims

1. A large flow electro-hydraulic servo valve, characterized in that: include: A valve body (1) is formed with a valve cavity (10) and a first mounting opening (100) and a second mounting opening (101) located at two ends of the valve cavity (10); A valve sleeve (2) fixedly disposed in the valve cavity (10), the valve sleeve (2) being formed with a channel (20) and a first opening (200) and a second opening (201) located on both sides of the channel (20); a valve core (3) which is slidably disposed in the channel (20) and has a first sliding column end (31) and a second sliding column end (32); the valve core (3) is configured to be able to slide relative to the valve sleeve (2) under the drive of oil flowing into the channel (20); a displacement sensor (4), which is arranged on the valve body (1) and is located on the side where the first installation port (100) and the first opening (200) are located, and the displacement sensor (4) is used to detect the movement stroke of the valve core (3); and, Two shaft sleeves (5), the two shaft sleeves (5) are respectively fixedly arranged at the first opening (200) and the second opening (201) and are respectively slidably sleeved outside the first sliding column end (31) and the second sliding column end (32), and the two shaft sleeves (5) are respectively matched with the first sliding column end (31) and the second sliding column end (32) to prevent oil leakage in the channel (20); The end surface of the second sliding column end (32) is configured to be exposed to the outside through the second opening (201) and the second installation port (101), so that the movement stroke of the valve core (3) can be detected from the side where the second installation port (101) is located.

2. The large flow electro-hydraulic servo valve according to claim 1, characterized in that: The large-flow electro-hydraulic servo valve further comprises an end cover (6), wherein the end cover (6) is sealed at the second mounting opening (101); The end cover (6) is detachably arranged on the valve body (1); or, the end cover (6) comprises a main body portion (60) fixedly arranged on the valve body (1) and a disassembly portion (61) detachably arranged on the main body portion (60).

3. The large flow electro-hydraulic servo valve according to claim 1 or 2, characterized in that: The displacement sensor (4) comprises a housing (40), a detection coil (41) disposed in the housing (40), and an iron core (42) extending from the housing (40); the iron core (42) is fixedly connected to the first sliding column end (31); and the detection coil (41) is used to detect the movement of the iron core (42) to obtain the movement stroke of the valve core (3).

4. The large flow electro-hydraulic servo valve according to claim 3, characterized in that: The iron core (42) is provided with an external thread, the first sliding column end (31) is provided with an internal thread, and the iron core (42) is threadedly connected to the first sliding column end (31).

5. The large flow electro-hydraulic servo valve according to claim 4, characterized in that: A first locking nut (43) is threadedly connected to the iron core (42), and the first locking nut (43) abuts against the first sliding column end (31) after the iron core (42) is tightened on the first sliding column end (31).

6. The large flow electro-hydraulic servo valve according to claim 3, characterized in that: The large-flow electro-hydraulic servo valve further comprises a sensor mounting seat (7), the sensor mounting seat (7) being fixedly arranged at the first mounting port (100), and the sensor mounting seat (7) being provided with a threaded hole, and the displacement sensor (4) being threadedly connected to the sensor mounting seat (7) through the housing (40).

7. The large flow electro-hydraulic servo valve according to claim 6, characterized in that: A second locking nut is threadedly connected to the housing (40), and the second locking nut abuts against the sensor mounting seat (7) after the housing (40) is tightened on the sensor mounting seat (7).

8. The large flow electro-hydraulic servo valve according to claim 1 or 2, characterized in that: The valve core (3) further comprises a main body shaft (30) located between the first sliding column end (31) and the second sliding column end (32), and a first boss (33) continuous with the first sliding column end (31) and a second boss (34) continuous with the second sliding column end (32) are formed on the main body shaft (30); The outer diameter of the first boss (33) is greater than the outer diameter of the first sliding column end (31) to form a first control surface (330) therebetween; the inner wall of the channel (20), the outer surface of the first sliding column end (31), the first control surface (330) and the inner end surface of one of the shaft sleeves (5) cooperate to enclose and form a first oil chamber (37); the valve sleeve (2) is provided with a first control oil flow channel (21) communicating with the first oil chamber (37); The outer diameter of the second boss (34) is greater than the outer diameter of the second sliding column end (32) to form a second control surface (340) therebetween; the inner wall of the channel (20), the outer surface of the second sliding column end (32), the second control surface (340) and the inner end surface of the other sleeve (5) cooperate to enclose a second oil chamber (38); the valve sleeve (2) is provided with a second control oil flow channel (22) communicating with the second oil chamber (38).

9. The large flow electro-hydraulic servo valve according to claim 8, characterized in that: The ratio of the outer diameter of the first sliding column end (31) to the outer diameter of the first boss (33) is a selected value between 0.5 and 0.6; The ratio of the outer diameter of the second sliding column end (32) to the outer diameter of the second boss (34) is a selected value between 0.5 and 0.

6.

10. The large flow electro-hydraulic servo valve according to claim 8, characterized in that: The sleeve (5) comprises a first annular segment (50), a second annular segment (51) having a smaller diameter than the first annular segment (50), and a transition segment (52) located between the first annular segment (50) and the second annular segment (51), wherein the transition segment (52) has a guiding inclined surface; The second annular section (51) and the transition section (52) on one of the shaft sleeves (5) are arranged corresponding to the first control oil flow channel (21) to guide the control oil to flow toward the first control surface (330), and the second annular section (51) and the transition section (52) on the other shaft sleeve (5) are arranged corresponding to the second control oil flow channel (22) to guide the control oil to flow toward the second control surface (340).

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