A servo valve with double valve core

Abstract

The present application discloses a servo valve with a double valve core, including a first valve seat, a second valve seat, an inner valve core, a first drive assembly and a second drive assembly; the inner valve core is seal-slidably mounted on the first valve seat to form a small-opening servo valve, and the first drive assembly is suitable for driving the inner valve core to move along the first valve seat to adjust the opening; the first valve seat is seal-slidably mounted on the second valve seat, so that the first valve seat acts as a valve core and cooperates with the second valve seat to form a large-opening servo valve, and the second drive assembly is suitable for driving the small-opening servo valve as a whole to move along the second valve seat to adjust the opening. Beneficial effects of the present application: By integrating the two-stage valve core structure, a small-opening servo valve and a large-opening servo valve structure that do not interfere with each other can be formed, so that different flow rates can be accurately controlled according to different application scenarios.

Description

Technical Field

[0001] The present application relates to the field of valve technology, and in particular to a servo valve with a double valve core. Background Art

[0002] The servo valve is a commonly used control element in hydraulic systems, which can realize flow control, pressure control, direction control and automatic adjustment of hydraulic systems. Taking pressure control as an example, the servo valve adjusts the opening of the valve port by moving its own valve core to achieve pressure control.

[0003] Under the condition of constant pressure, there are two main ways to control the movement of the valve core of the servo valve. One is the linear gain mode, that is, the valve opening and the valve core displacement are in a linear relationship; the other is the nonlinear mode, that is, the valve opening and the valve core displacement are in a multi-power relationship. For the above two control methods, under the same diameter, the flow regulation accuracy of the nonlinear mode at a small opening is higher than that of the linear mode, but the flow regulation accuracy at a large opening is lower than that of the linear mode. Therefore, the existing hydraulic system often needs to set up multiple servo valves of different modes for different opening requirements, which will make the overall connection structure of the hydraulic system complicated and the cost is relatively high. Summary of the invention

[0004] One of the objectives of the present application is to provide a dual valve core servo valve that can solve at least one of the defects in the above-mentioned background technology.

[0005] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: a dual-valve core servo valve, comprising a first valve seat, a second valve seat, an inner valve core, a first drive assembly and a second drive assembly; the inner valve core is seal-slidingly installed on the first valve seat to form a small-opening servo valve, and the first drive assembly is suitable for driving the inner valve core to move along the first valve seat to adjust the opening; the first valve seat is seal-slidingly installed on the second valve seat, so that the first valve seat acts as a valve core and cooperates with the second valve seat to form a large-opening servo valve, and the second drive assembly is suitable for driving the small-opening servo valve as a whole to move along the second valve seat to adjust the opening.

[0006] Preferably, the first drive assembly includes a first drive device and a first traction member; the first drive device is fixedly mounted on the outside of the second valve seat, one end of the first traction member is driven and cooperated with the first drive device, and the other end passes through the second valve seat and is connected to the inner valve core in the first valve seat; the first traction member is suitable for driving the inner valve core to move along the first valve seat under the drive of the first drive device.

[0007] Preferably, the first driving device adopts a motor, and the inner valve core adopts a non-circular cross-section or is rotationally limited with the first valve seat; the first traction member includes a first transmission member and a first driving rod; the first transmission member is rotatably installed on the first valve seat, one end of the first transmission member is transmission-coordinated with the first driving device, and the other end is threaded or screw-coordinated with the first driving rod; the end of the first driving rod away from the first transmission member is fixedly connected to the inner valve core.

[0008] Preferably, the first transmission member includes a first rotating sleeve and a first transmission shaft; the first rotating sleeve is rotatably installed on the first valve seat and is threaded or screw-matched with the first drive rod; one end of the first transmission shaft is fixedly connected to the first rotating sleeve, and the other end is transmission-matched with the first drive device.

[0009] Preferably, the output end of the first drive device is spline-coupled with the first transmission member; or, the output end of the first drive device is meshed with a second gear provided on the first transmission member through a first gear, and the width difference between the first gear and the second gear is greater than or equal to the opening stroke of the large-opening servo valve.

[0010] Preferably, the second drive assembly includes a second drive device and a second traction member; the second drive device is fixedly mounted on the outside of the second valve seat, the second traction member is sleeved on the first traction member, one end of the second traction member is driven and cooperated with the second drive device, and the other end is arranged in the second valve seat and connected with the first valve seat; the second traction member is suitable for driving the small-opening servo valve to move under the drive of the second drive device.

[0011] Preferably, the second driving device adopts a motor, the first valve seat adopts a non-circular cross-section or is rotationally limited with the second valve seat; the second traction member includes a second transmission member and a second driving rod; the second transmission member is rotatably installed on the second valve seat, one end of the second transmission member is gear-coupled with the second driving device, and the other end is threaded or screwed with the second driving rod; the end of the second driving rod away from the second transmission member is fixedly connected to the first valve seat.

[0012] Preferably, the second transmission member includes a second rotating sleeve and a second transmission shaft; the second rotating sleeve is rotatably mounted on the second valve seat and is threaded or screw-coupled with the second drive rod; one end of the second transmission shaft is fixedly connected to the second rotating sleeve, and the other end is gear-coupled with the second drive device.

[0013] Preferably, the inner valve core is sealingly slidably installed in the first inner cavity of the first valve seat, and the first valve seat is sealingly slidably installed in the second inner cavity of the second valve seat; an oil path connecting the oil inlet of the first valve seat and the first inner cavity is provided in the inner valve core; and the first valve seat is provided with a first oil port connecting the second inner cavity on the side of the first inner cavity.

[0014] Preferably, the oil inlet of the first valve seat cooperates with the inner valve core through a conical surface, and the oil inlet of the second valve seat also cooperates with the first valve seat through a conical surface.

[0015] Compared with the prior art, the beneficial effects of this application are:

[0016] By integrating the two-stage valve core structure, a small-opening servo valve and a large-opening servo valve structure that do not interfere with each other can be formed, thereby accurately controlling different flow rates according to different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the overall structure of this application.

[0018] Figure 2 This is a schematic diagram of the local structure of the small-opening servo valve in this application when it is opened.

[0019] Figure 3 It is a schematic diagram of the local structure when the large-opening servo valve in this application is opened.

[0020] In the figure: a first valve seat 1, a first valve port 10, a first oil port 11, a first inner cavity 12, an inner valve core 2, a second oil port 20, a third oil port 21, a second valve seat 3, a second valve port 30, a second inner cavity 31, a first drive assembly 4, a first drive device 41, a first gear 411, a first transmission shaft 42, a second gear 421, a first rotating sleeve 43, a first drive rod 44, a second drive assembly 5, a second drive device 51, a third gear 511, a second transmission shaft 52, a fourth gear 521, a second rotating sleeve 53, a second drive rod 54, and a mounting cover 6. DETAILED DESCRIPTION

[0021] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0022] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present application.

[0023] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0024] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0026] The terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0027] One of the preferred embodiments of the present application is as follows: Figure 1 As shown, a servo valve with a double valve core includes a first valve seat 1, a second valve seat 3, an inner valve core 2, a first drive assembly 4, and a second drive assembly 5. The inner valve core 2 is sealed and slidably mounted on the first valve seat 1 to form a small opening servo valve, and then the inner valve core 2 realizes the opening adjustment of the first valve port 10 on the first valve seat 1 by moving along the first valve seat 1. The first drive assembly 4 can be installed on the second valve seat 3 or externally installed at other positions, and it is only necessary that the first drive assembly 4 can be stably driven; the first drive assembly 4 can be driven and matched with the inner valve core 2, and then the inner valve core 2 moves along the first valve seat 1 under the drive of the first drive assembly 4 to adjust the opening. The first valve seat 1 is sealed and slidably mounted on the second valve seat 3, so that the first valve seat 1 can be used as a valve core to cooperate with the second valve seat 3 to form a large opening servo valve, and then the first valve seat 1 realizes the opening adjustment of the second valve port 30 on the second valve seat 3 by moving along the second valve seat 3. The second drive component 5 can be installed on the second valve seat 3 or installed externally at other locations, and it only needs to include the first drive component 4 to be able to operate stably; the second drive component 5 can cooperate with the first valve seat 1 for driving, and then the first valve seat 1 moves along the second valve seat 3 under the drive of the second drive component 5 to adjust the opening.

[0028] Compared with the traditional method, the present application integrates the two-stage valve core structure to form a small opening servo valve and a large opening servo valve structure that do not interfere with each other, so as to accurately control different flow rates according to different application scenarios. In addition, using the small opening servo valve as the valve core of the large opening servo valve can effectively reduce the number of parts of the servo valve, thereby saving costs and reducing the installation space requirements of the servo valve.

[0029] It is understandable that if Figures 1 to 3 As shown, the oil inlets of the first valve seat 1 and the second valve seat 3 are on the same side, the first valve port 10 of the first valve seat 1 and the second valve port 30 of the second valve seat 3 are interconnected, and the opening size of the first valve port 10 is smaller than the opening size of the second valve port 30.

[0030] When nonlinear opening control is required in a small opening scenario, the first valve seat 1 needs to ensure that the port and the oil inlet of the second valve seat 3 are in a sealed state; at this time, the inner valve core 2 is driven by the first drive component 4 to slide along the first inner cavity 12 of the first valve seat 1 to seal and open the first valve port 10, and then the oil will enter from the oil inlet of the first valve seat 1, and then flow out from the second valve port 30 after passing through the opened first valve port 10; the specific flow route is as follows Figure 2 Indicated by the dotted line.

[0031] When linear opening control is required in a large opening scenario, the port of the first valve seat 1 and the oil inlet of the second valve seat 3 can be in a sealed state or directly in an open state. It is only necessary to ensure that the inner valve core 2 and the first valve seat 1 remain relatively still during the subsequent opening adjustment process. For the convenience of description, the following description will be based on the example that the port of the first valve seat 1 and the oil inlet of the second valve seat 3 are in a sealed state. Then, driven by the second drive component 5, the first valve seat 1 slides in a sealed manner along the second inner cavity 31 of the second valve seat 3 to open the second valve port 30, and then the oil will enter from the oil inlet of the second valve seat 3, and then flow out along the opened second valve port 30. The specific flow route is as follows: Figure 3 It should be noted that, during the movement of the first valve seat 1 , the inner valve core 2 needs to keep moving synchronously with the first valve seat 1 .

[0032] It should be known that in order to ensure stable sealing of the oil inlet between the inner valve core 2 and the first valve seat 1, and to ensure stable sealing of the oil inlet between the first valve seat 1 and the second valve seat 3, the oil inlet of the first valve seat 1 can be matched with the port of the inner valve core 2 through a conical surface, and the oil inlet of the second valve seat 3 can also be matched with the port of the first valve seat 1 through a conical surface.

[0033] In this embodiment, Figure 1As shown, the first drive assembly 4 includes a first drive device 41 and a first traction member; the first drive device 41 is fixedly installed outside the second valve seat 3, one end of the first traction member is driven and matched with the output end of the first drive device 41, and the other end of the first traction member can pass through the second valve seat 3 and connect with the inner valve core 2 in the first valve seat 1. When the opening of the small opening servo valve needs to be adjusted, the first drive device 41 can be started, and then the first traction member can drive the inner valve core 2 to move along the first valve seat 1 under the drive of the first drive device 41.

[0034] It can be understood that the first traction member drives the inner valve core 2 to move in a linear motion, and there are multiple specific driving modes in which the first drive device 41 drives the first traction member to realize the linear motion of the inner valve core 2. For example, the first drive device 41 can directly drive the first traction member to move in a linear manner to drive the inner valve core 2 to move synchronously; for example, the first drive device 41 drives the first traction member to rotate, and then realizes the linear motion of the inner valve core 2 through a transmission structure such as a screw rod or a thread.

[0035] It should be known that if the first drive device 41 directly drives the first traction member to perform linear motion, then the common structure of the first drive device 41 is a cylinder or a hydraulic cylinder, which means that the first drive device 41 also needs to be additionally configured with an air source or an oil source. In addition, both the cylinder and the hydraulic cylinder may leak, and the leakage of the cylinder or the hydraulic cylinder will reduce the opening control accuracy of the small opening servo valve. Therefore, in this embodiment, the first drive device 41 drives the first traction member to move the inner valve core 2 by rotating, that is, the first drive device 41 preferably uses a motor, and the servo control of the motor can achieve precise control of the opening of the small opening servo valve.

[0036] Specifically, Figure 1 and Figure 2 As shown, the inner valve core 2 adopts a non-circular cross-section or is rotationally limited with the first valve seat 1, so that the inner valve core 2 can perform stable linear motion later. The first traction member includes a first transmission member and a first drive rod 44; the first transmission member is rotatably mounted on the first valve seat 1, one end of the first transmission member is transmission-matched with the first drive device 41, and the other end is threaded or screwed with the first drive rod 44. The end of the first drive rod 44 away from the first transmission member is fixedly connected to the inner valve core 2.

[0037] When the opening of the small opening servo valve needs to be controlled, the first drive device 41 will be started, and then the first transmission member will rotate under the drive of the first drive device 41. Since the first transmission member can only rotate around the first valve seat 1 and cannot move axially, the first transmission member cooperates with the thread or screw of the first drive rod 44 to drive the first drive rod 44 to drive the inner valve core 2 to move axially. For the nonlinear mode of the inner valve core 2, it can be achieved by controlling the rotation speed of the first drive device 41 non-constantly.

[0038] It should be known that, taking the threaded engagement of the first transmission member and the first driving rod 44 as an example, the first transmission member can be inserted into the first driving rod 44 for threaded engagement, or the first driving rod 44 can be inserted into the first transmission member for threaded engagement. There are many specific installation methods for the first transmission member and the first driving rod 44. For ease of understanding, a detailed description will be given below using one of the structures as an example.

[0039] Specifically, Figures 1 to 3 As shown, the first transmission member includes a first rotating sleeve 43 and a first transmission shaft 42. A pair of mounting covers 6 are arranged at intervals along the length direction on the inner side of the first valve seat 1. The mounting covers 6 can be fixedly connected to the first valve seat 1 by welding or bolting, so that a rotating mounting space can be formed between the two mounting covers 6. The first rotating sleeve 43 is located in the rotating mounting space and cooperates with the two mounting covers 6 respectively through thrust bearings at both ends, so that the first rotating sleeve 43 is rotatably mounted on the first valve seat 1. The first transmission shaft 42 is fixedly connected to one end of the first rotating sleeve 43 away from the inner valve core 2, and the other end of the first transmission shaft 42 extends out of the second valve seat 3 and is transmission-coordinated with the first driving device 41. The first driving rod 44 can be threaded or screwed with the first rotating sleeve 43, and then when the first driving device 41 is started, the first transmission shaft 42 can drive the first rotating sleeve 43 to rotate synchronously, so that the first rotating sleeve 43 drives the inner valve core 2 to move by cooperating with the thread or screw of the first driving rod 44.

[0040] It should be known that, from the above content, when the large-opening servo valve is started, the entire small-opening servo valve will move along the second valve seat 3. Since the first transmission shaft 42 is fixedly connected to the first rotating sleeve 43, the first transmission shaft 42 will move synchronously with the small-opening servo valve. In order to ensure the stable connection between the first drive device 41 and the first transmission shaft 42, either the first drive device 41 is set to float, that is, the first drive device 41 can move axially synchronously with the first transmission shaft 42; or a floating structure is set between the output end of the first drive device 41 and the first transmission shaft 42, so that the first transmission shaft 42 can move axially relative to the first drive device 41 while maintaining a stable transmission connection with the first drive device 41. Considering the actual application scenario, the floating setting of the first drive device 41 may not meet the application of some scenarios. Therefore, in this embodiment, it is preferred to set a floating structure between the output end of the first drive device 41 and the first transmission shaft 42. Since the specific installation positions of the first driving device 41 and the first transmission shaft 42 are different, the specific structure of the floating structure is also different. For the sake of easy understanding, two specific examples will be used for detailed description below.

[0041] Example 1: The output end of the first driving device 41 is colinear with the axis of the first transmission shaft 42; then the output end of the first driving device 41 can be spline-driven with the first transmission shaft 42 to form a floating structure.

[0042] Example 2: If Figure 1 As shown, the output end of the first driving device 41 is not colinear with the axis of the first transmission shaft 42; the output end of the first driving device 41 is meshed with the second gear 421 provided on the first transmission shaft 42 through the first gear 411, and there is a width difference between the first gear 411 and the second gear 421, and the width difference is greater than or equal to the opening stroke of the large opening servo valve. Specifically, the width of the first gear 411 can be greater than the width of the second gear 421, or the width of the second gear 421 can be greater than the width of the first gear 411, and the specific selection can be made according to the actual needs of those skilled in the art.

[0043] In this embodiment, Figure 1As shown, the second drive assembly 5 includes a second drive device 51 and a second traction member; the second drive device 51 is fixedly installed on the outside of the second valve seat 3, and the second traction member is sleeved on the first traction member, that is, the first traction member and the second traction member are in smooth contact or non-contact; one end of the second traction member is driven and matched with the second drive device 51, and the other end of the second traction member is arranged in the second valve seat 3 and connected with the first valve seat 1. When the opening of the large-opening servo valve needs to be adjusted, the second drive device 51 can be started, and then the second traction member can drive the entire small-opening servo valve to move along the second valve seat 3 under the drive of the second drive device 51.

[0044] It can be understood that the second traction member drives the small-opening servo valve to operate in a linear motion, and there are multiple specific driving methods for the second drive device 51 to drive the second traction member to realize the linear motion of the small-opening servo valve. For example, the second drive device 51 can directly drive the second traction member to move linearly to drive the small-opening servo valve to move synchronously; for example, the second drive device 51 drives the second traction member to rotate, and then realizes the linear motion of the small-opening servo valve through a transmission structure such as a screw rod or a thread.

[0045] It should be known that if the second drive device 51 directly drives the second traction member to perform linear motion, then the common structure of the second drive device 51 is a cylinder or a hydraulic cylinder, which means that the second drive device 51 also needs to be additionally configured with an air source or an oil source. In addition, both the cylinder and the hydraulic cylinder may leak, and the leakage of the cylinder or the hydraulic cylinder will reduce the opening control accuracy of the large-opening servo valve. Therefore, in this embodiment, the second drive device 51 drives the second traction member to move the small-opening servo valve by rotating it, that is, the second drive device 51 preferably uses a motor, and the servo control of the motor can achieve precise control of the opening of the small-opening servo valve.

[0046] Specifically, Figures 1 to 3 As shown, the first valve seat 1 adopts a non-circular cross-section or is rotationally limited with the second valve seat 3, so that the first valve seat 1 can perform stable linear motion later. The second traction member includes a second transmission member and a second drive rod 54; the second transmission member is rotatably mounted on the second valve seat 3, one end of the second transmission member is gear-coupled with the second drive device 51, and the other end is threaded or screwed with the second drive rod 54; the end of the second drive rod 54 away from the second transmission member is fixedly connected to the first valve seat 1.

[0047] When the opening of the large-opening servo valve needs to be controlled, the second drive device 51 will be started, and then the second transmission member will rotate under the drive of the second drive device 51. Since the second transmission member can only rotate around the second valve seat 3 and cannot move axially, the second transmission member cooperates with the thread or screw of the second drive rod 54 to drive the second drive rod 54 to drive the first valve seat 1 to move axially. For the linear operation mode of the small-opening servo valve, it can be achieved by constantly controlling the rotation speed of the second drive device 51.

[0048] It should be known that, taking the threaded engagement of the second transmission member and the second drive rod 54 as an example, the second transmission member can be inserted into the second drive rod 54 for threaded engagement, or the second drive rod 54 can be inserted into the second transmission member for threaded engagement. There are many specific installation methods for the second transmission member and the second drive rod 54. For ease of understanding, a detailed description will be given below using one of the structures as an example.

[0049] Specifically, Figures 1 to 3 As shown, the second transmission member includes a second rotating sleeve 53 and a second transmission shaft 52. The rotational installation position of the second rotating sleeve 53 is located in the second valve seat 3, and the specific installation method is basically the same as that of the first rotating sleeve 43, so it will not be elaborated in detail here. The second transmission shaft 52 is fixedly connected to the end of the second rotating sleeve 53 away from the small opening servo valve, and the other end of the second transmission shaft 52 extends out of the second valve seat 3 and meshes with the third gear 511 at the output end of the second drive device 51 through a fixedly installed fourth gear 521. The second drive rod 54 can be threaded or screwed with the second rotating sleeve 53, and then when the second drive device 51 is started, the second transmission shaft 52 can drive the second rotating sleeve 53 to rotate synchronously, so that the second rotating sleeve 53 drives the small opening servo valve to move by cooperating with the thread or screw of the second drive rod 54.

[0050] It should be noted that, in order to ensure that the large opening servo valve and the small opening servo valve do not interfere with each other, the second transmission shaft 52 and the second drive rod 54 are both provided with through holes in their centers, and the first transmission shaft 42 can extend along the through holes in the centers of the second transmission shaft 52 and the second drive rod 54 to the first valve seat 1 and connect with the inner valve core 2. The diameter of the first transmission shaft 42 is smaller than the inner diameter of the through holes in the centers of the second transmission shaft 52 and the second drive rod 54.

[0051] In this embodiment, Figures 1 to 3As shown, the inner valve core 2 is sealingly and slidably mounted on the first inner cavity 12 of the first valve seat 1, and the first valve seat 1 is sealingly and slidably mounted on the second inner cavity 31 of the second valve seat 3. An oil passage connecting the oil inlet of the first valve seat 1 and the first inner cavity 12 is provided in the inner valve core 2. The first valve seat 1 is provided with a first oil port 11 connecting the second inner cavity 31 on the side of the first inner cavity 12. By setting the oil passage and the first oil port 11, the pressure balance at both ends of the valve core can be maintained during the operation of the small opening servo valve and the large opening servo valve, thereby reducing the movement resistance of the valve core when the opening is reduced.

[0052] Specifically, Figures 1 to 3 As shown, a second oil port 20 and a third oil port 21 are provided inside the inner valve core 2; the second oil port 20 is located at the center of the inner valve core 2 and one end is connected to the oil inlet of the first valve seat 1, and the number of the third oil port 21 can be multiple and evenly arranged along the circumferential direction of the inner valve core 2, one end of the third oil port 21 is connected to the first inner cavity 12 of the first valve seat 1, and the other end is connected to the second oil port 20.

[0053] It can be understood that, taking a small opening servo valve as an example, when the inner valve core 2 needs to move in the direction of increasing the opening, the inner valve core 2 can move away from the oil inlet of the first valve seat 1 under the action of the oil pressure. If the oil passage is not provided, when the inner valve core 2 needs to move in the direction of decreasing the opening, since the oil supply pressure of the oil inlet remains unchanged, the movement trend of the inner valve core 2 will squeeze the oil at the oil inlet, causing the pressure at the oil inlet position to increase, thereby increasing the movement resistance of the inner valve core 2. After the oil passage is provided on the inner valve core 2, before the inner valve core 2 moves, the oil at the oil inlet position of the first valve seat 1 will flow into the first inner cavity 12 and the second inner cavity 31 along the oil passage, so that the pressure at both ends of the inner valve core 2 tends to be consistent. Therefore, when the inner valve core 2 needs to move to reduce the opening, the oil storage space of the first inner cavity 12 will increase with the movement of the inner valve core 2, and part of the oil at the oil inlet of the first valve seat 1 can flow into the first inner cavity 12 along the oil path, which will greatly reduce the movement resistance of the inner valve core 2, thereby ensuring that the opening control process of the inner valve core 2 can be carried out smoothly, so as to further improve the opening control accuracy. The specific oil flow direction for maintaining the pressure balance at both ends of the valve core is as follows: Figure 2 and Figure 3 Shown by the dashed line.

[0054] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A servo valve with a double valve core, characterized in that: include: First valve seat; Internal valve core; The inner valve core is sealingly and slidably mounted on the first valve seat to form a small opening servo valve; a first drive assembly; The first driving assembly is suitable for driving the inner valve core to move along the first valve seat to adjust the opening; The first valve seat is sealingly and slidably mounted on the second valve seat, so that the first valve seat acts as a valve core and cooperates with the second valve seat to form a large-opening servo valve; as well as The second drive assembly is suitable for driving the small-opening servo valve to move as a whole along the second valve seat to adjust the opening.

2. The dual-spool servo valve according to claim 1, characterized in that: The first driving assembly comprises: A first driving device; the first driving device is fixedly mounted outside the second valve seat; and A first traction member; one end of the first traction member is driven and cooperated with the first driving device, and the other end passes through the second valve seat and is connected to the inner valve core in the first valve seat; the first traction member is suitable for driving the inner valve core to move along the first valve seat under the drive of the first driving device.

3. The dual-spool servo valve according to claim 2, characterized in that: The first driving device adopts a motor, and the inner valve core adopts a non-circular cross-section or cooperates with the first valve seat to rotate and limit; The first traction member comprises: A first transmission member; the first transmission member is rotatably mounted on the first valve seat, and one end of the first transmission member is in transmission cooperation with the first driving device; and a first driving rod; the other end of the first transmission member is threaded or screwed with the first driving rod; an end of the first driving rod away from the first transmission member is fixedly connected with the inner valve core.

4. The dual-spool servo valve according to claim 3, characterized in that: The first transmission member comprises: A first rotating sleeve; the first rotating sleeve is rotatably mounted on the first valve seat and is threaded or screw-matched with the first driving rod; and A first transmission shaft; one end of the first transmission shaft is fixedly connected to the first rotating sleeve, and the other end is in transmission cooperation with the first driving device.

5. The dual-spool servo valve according to claim 3, characterized in that: The output end of the first driving device is spline-coupled with the first transmission member; Alternatively, the output end of the first driving device is meshed with a second gear provided on the first transmission member through a first gear, and a width difference between the first gear and the second gear is greater than or equal to an opening stroke of the large-opening servo valve.

6. The dual-spool servo valve according to claim 2, characterized in that: The second driving assembly comprises: A second driving device; the second driving device is fixedly mounted outside the second valve seat; and A second traction member; the second traction member is sleeved on the first traction member, one end of the second traction member is driven and cooperated with the second driving device, and the other end is arranged in the second valve seat and connected with the first valve seat; the second traction member is suitable for driving the small-opening servo valve to move under the drive of the second driving device.

7. The dual-spool servo valve according to claim 6, characterized in that: The second driving device adopts a motor, and the first valve seat adopts a non-circular cross-section or cooperates with the second valve seat in rotation and limiting position; The second traction member comprises: A second transmission member; the second transmission member is rotatably mounted on the second valve seat, and one end of the second transmission member is gear-coupled with the second drive device; and a second driving rod; the other end of the second transmission member is threaded or screwed with the second driving rod; and one end of the second driving rod away from the second transmission member is fixedly connected with the first valve seat.

8. The dual-spool servo valve according to claim 7, characterized in that: The second transmission member comprises: A second rotating sleeve; the second rotating sleeve is rotatably mounted on the second valve seat and is threaded or screw-matched with the second driving rod; and A second transmission shaft; one end of the second transmission shaft is fixedly connected to the second rotating sleeve, and the other end is gear-driven with the second driving device.

9. The dual valve core servo valve according to any one of claims 1 to 8, characterized in that: The inner valve core is sealingly and slidably mounted in the first inner cavity of the first valve seat, and the first valve seat is sealingly and slidably mounted in the second inner cavity of the second valve seat; An oil passage communicating with the oil inlet of the first valve seat and the first inner cavity is arranged in the inner valve core; a first oil passage communicating with the second inner cavity is arranged on the side of the first inner cavity of the first valve seat.

10. The dual-spool servo valve according to claim 1, wherein: The oil inlet of the first valve seat cooperates with the inner valve core through a conical surface, and the oil inlet of the second valve seat also cooperates with the first valve seat through a conical surface.

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