An electric motor and a servo valve

Abstract

The present application relates to the technical field of hydraulic pressure, and particularly relates to a motor and a servo valve. A motor comprises: a shell; a magnetic group assembly installed in the shell, comprising an outer ring magnetic group and an inner ring magnetic group arranged at intervals, and an annular space formed between the outer ring magnetic group and the inner ring magnetic group; a coil assembly movably installed in the annular space, and moving along an axial direction when the coil assembly is electrified; the coil assembly comprising a coil framework and a winding, and one end of the coil framework forming a mounting structure to connect a driven structure; a sensing assembly sensing the movement of the mounting structure, and the sensing assembly comprising a sensing iron core, a sensing coil and a PCB board, the sensing iron core moving with the mounting structure, the sensing coil being assembled on the PCB board and cooperating with the sensing iron core to sense, and the coil assembly and the sensing coil being electrically connected with the PCB board. The technical problem that the axial size of the overall structure of the servo valve in the prior art is large and the required installation space is large is solved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, specifically to an electric motor and a servo valve. Background Technology

[0002] The requirements for the precision and response speed of control valves are increasing in high-performance hydraulic control scenarios in industries such as injection molding machines, die casting machines, presses, and metallurgy.

[0003] In existing technologies, proportional valves driven by proportional electromagnets, dual-nozzle baffles, or jet-tube servo valves are often used to achieve hydraulic control. For example, document CN218333323U discloses a proportional electromagnet for a proportional valve; document CN119802265B discloses a dual-nozzle baffle type electro-feedback servo valve driven by a linear motor. The above-mentioned servo valves can all achieve control of the valve core position. However, the improvement of the response speed of proportional valves driven by proportional electromagnets has reached a bottleneck and it is difficult to make significant improvements. Although dual-nozzle baffles or jet-tube servo valves have a fast response, they are expensive, have weak anti-pollution ability, and have strict requirements on the application environment and operating conditions.

[0004] To address the technical problems of slow response, high cost, and weak contamination resistance in servo valves, existing technologies have introduced servo valves driven by voice coil motors, which solve these issues. For example, document CN107061398B discloses a servo proportional valve using a voice coil motor. This servo valve is a slide-valve type high-pressure electro-pneumatic servo valve with a three-position, three-way function. The linear voice coil motor of the servo valve includes a motor housing, an annular permanent magnet, and a moving coil winding. The servo valve body and motor housing are connected by screws. The servo valve sleeve has three sealing rings, and a third O-ring seal is used to seal between the servo valve body and the servo valve sleeve. The servo valve sleeve abuts against the left end of the center hole of the servo valve body, achieving axial positioning of the servo valve sleeve. The left end of the servo valve core is threadedly connected to a displacement sensor positioning plate, and the right end of the servo valve core is connected to a positioning sleeve, which is fixed to the moving coil winding of the motor via a connecting nut. The servo valve displacement sensor is connected to the center hole of the displacement sensor positioning seat via a fastening nut, and the positioning seat is fixed to the left end of the servo valve body via a threaded connection. The controller is electrically connected to the moving coil winding, the main valve displacement sensor, and the servo valve displacement sensor via wires. The servo valve displacement sensor sends the detected valve core displacement to the controller. The controller amplifies and processes the difference signal between the servo valve core displacement and the displacement command signal, and then sends it to the moving coil winding of the voice coil motor to form a closed-loop control of the valve core position.

[0005] The servo proportional valve in the aforementioned document uses a voice coil motor to drive the valve core, which has a fast response and a large driving force; however, in order to achieve closed-loop control, the aforementioned proportional solenoid valve has a displacement sensor installed at the end away from the voice coil motor, which increases the axial dimension of the overall structure and requires a large installation space. Summary of the Invention

[0006] To address the technical problem of large axial dimensions and large installation space required for existing servo valves, this invention provides a motor and a servo valve that solve the aforementioned technical problems.

[0007] The technical solution of the present invention is as follows:

[0008] This invention provides an electric motor, comprising:

[0009] shell;

[0010] A magnetic assembly is installed inside a housing. The magnetic assembly includes an outer ring magnetic group and an inner ring magnetic group that are spaced apart, and an annular space is formed between the outer ring magnetic group and the inner ring magnetic group.

[0011] A coil assembly is movably mounted within the annular space. When energized, the coil assembly moves axially. The coil assembly includes a coil frame and windings. One end of the coil frame forms a mounting structure to connect to the driven structure.

[0012] A sensing component is provided to sense the movement of the mounting structure. The sensing component includes a sensing core, a sensing coil, and a PCB board. The sensing core moves with the mounting structure. The sensing coil is mounted on the PCB board and works in conjunction with the sensing core to sense the movement. Both the coil assembly and the sensing coil are electrically connected to the PCB board.

[0013] According to one embodiment of the present invention, one end of the coil frame extends to form a mounting cylinder, the mounting cylinder is located on the axis of the motor, the mounting cylinder is inserted into a mounting shaft, the induction core is limited and installed between the mounting shaft and the mounting cylinder, and the gap of the induction coil is located on the outer periphery of the mounting cylinder.

[0014] According to one embodiment of the present invention, the inner end of the PCB board is placed inside the housing, the outer edge of the inner end of the PCB board is attached to the inner wall of the housing, and the outer end of the PCB board extends out of the housing.

[0015] According to one embodiment of the present invention, a through hole is formed at the inner end of the PCB board, the through hole is coaxially arranged with the mounting structure, the mounting structure passes through the through hole, the skeleton part of the induction coil is fixedly connected to the PCB board, and the coil part of the induction coil is placed in the through hole.

[0016] According to one embodiment of the present invention, the connection point of the PCB board is located on the surface away from the magnetic assembly, and the coil frame further extends with a trace portion that passes through the PCB board, and the wound cable reaches the side of the PCB board away from the magnetic assembly via the trace portion.

[0017] According to one embodiment of the present invention, the outer ring magnetic assembly is formed by alternating axial arrangement of an outer annular axial permanent magnet and an outer annular magnetic conductor, and the inner ring magnetic assembly is formed by alternating axial arrangement of an inner cylindrical axial permanent magnet and an inner cylindrical magnetic conductor.

[0018] or,

[0019] The outer ring magnetic assembly is formed by alternating axial arrangements of outer annular axial permanent magnets and outer annular radial permanent magnets, and the inner ring magnetic assembly is formed by alternating axial arrangements of inner cylindrical axial permanent magnets and inner annular radial permanent magnets. The magnetization directions of adjacent outer annular axial permanent magnets are opposite, the magnetization directions of adjacent outer annular radial permanent magnets are opposite, the magnetization directions of adjacent inner cylindrical axial permanent magnets are opposite, and the magnetization directions of adjacent inner annular radial permanent magnets are opposite.

[0020] The present invention also provides a servo valve, comprising:

[0021] Electric motor;

[0022] A valve assembly, including a valve body and a valve core, wherein the valve core moves under the drive of the motor;

[0023] The controller is electrically connected to the PCB board.

[0024] According to one embodiment of the present invention, the end of the valve core is inserted into the end of the mounting structure, and a connecting pin is interference-fitted through the end of the valve core and the mounting structure to connect the two into one, and an elastic element is also provided between the valve core and the mounting structure.

[0025] According to one embodiment of the present invention, the valve body is provided with a pressure oil passage, a working oil passage and a return oil passage, the valve core is provided with a flow groove corresponding to the working oil passage, and a shoulder is formed in the flow groove; the valve core is provided with a cavity corresponding to the return oil passage.

[0026] According to one embodiment of the present invention, a reset structure is provided at the end of the valve core away from the motor.

[0027] Based on the above technical solution, the technical effects that the present invention can achieve are as follows:

[0028] 1. The motor of the present invention, by setting the sensing component to be mounted at the mounting structure of the coil component, facilitates the assembly of the sensing component without increasing the axial dimension of the overall structure. Moreover, the sensing component can sense the movement of the driven structure by sensing the movement of the mounting structure, thus meeting the requirements of closed-loop control. The sensing component includes a PCB board, which facilitates the assembly of the induction coil. On the other hand, the coil component and the induction coil can also be routed through the PCB board. The cable assembly and the induction coil can be electrically connected to the inner end of the PCB board, and the outer end of the PCB board is electrically connected to the controller. It is not necessary for the coil component and the induction coil to pass through the outer shell to be electrically connected to the controller separately, which can shorten the cable length, facilitate cable layout, and save space. The integration of the sensing component into the motor can reduce the external wiring harness, reduce the structural requirements of the driven structure, and make the voice coil motor more flexible in application scenarios. It can be adapted to various types of valve structures and can also be extended to be used as a driver for other products.

[0029] 2. The motor of the present invention has a coil frame mounting structure including a mounting cylinder and a mounting shaft. When the mounting shaft is inserted into the mounting cylinder, the induction core can be limited and installed. The through hole of the PCB board is coaxially arranged with the mounting structure. When the frame part of the induction coil is fixed on the PCB board, the coil part can be located in the through hole, and the gap is located on the outer periphery of the mounting structure, so that it can cooperate with the induction core for detection. The connection point of the PCB board is located on the surface away from the magnetic assembly. The winding cable reaches the side of the PCB board away from the magnetic assembly through the wiring part and is electrically connected to the PCB board. The cable of the induction coil reaches the side of the PCB board away from the magnetic assembly through the frame part and is electrically connected to the PCB board. This makes it so that no cable passes between the PCB board and the magnetic assembly, without increasing the space between the PCB board and the magnetic assembly, and without affecting the movement of the magnetic assembly.

[0030] 3. In the motor of the present invention, the outer ring magnetic assembly adopts an alternating axial arrangement of annular axial permanent magnets and annular magnetic conductors, while the inner ring magnetic assembly adopts an alternating axial arrangement of cylindrical axial permanent magnets and cylindrical magnetic conductors to form a double Halbach magnetic array structure. This structure can form multiple sets of annular magnetic field lines, increasing the magnetic field strength passing through the coil assembly, greatly increasing the output force of the motor, and thus improving the response speed of the hydraulic valve. The inner ring magnetic assembly uses solid cylindrical permanent magnets, which can increase the volume of the permanent magnets and increase the magnetic field strength. At the same time, the larger contact area can improve the heat conduction efficiency, which helps the motor dissipate heat, increases the maximum operating current of the motor and the stability of long-term operation, and increases the overall performance. Output force within the same volume; the use of a magnetic conductor allows adaptation to the direction of magnetic field lines and reduces costs; by changing the direction and magnitude of the current passing through the coil assembly, the direction and magnitude of the Ampere force on the coil assembly can be changed, thereby controlling the reciprocating linear motion of the motor; the structure is simple and easy to use; the motor generates output force by cutting magnetic field lines through winding, without producing pollution, and can adapt to various working conditions; the outer ring magnetic assembly can also be configured with alternating axial arrangement of annular radial permanent magnets and annular axial permanent magnets, or alternating axial arrangement of annular radial permanent magnets and cylindrical axial permanent magnets, which can further enhance the magnetic field strength and further improve the output force of the motor;

[0031] 4. The servo valve of the present invention has a controller that is directly electrically connected to the PCB board, which can realize current control of the winding, current control of the induction coil, and signal control.

[0032] 5. The servo valve of the present invention, after the valve core end is inserted into the end of the mounting structure, is connected as a whole by a connecting pin, which can ensure that the motor and the valve core are coaxially set; an elastic element is set between the valve core and the mounting structure, which can increase the shear force of the connection structure and strengthen the connection strength of the interference fit. The connection structure adopts a rigid connection, which not only ensures the reliability of the connection, but also ensures the coaxiality between the valve core and the motor, reduces friction loss, and reduces costs.

[0033] 6. In the servo valve of the present invention, a shoulder is added to the valve core. When the valve core moves, the resultant force of the shoulder is in the same direction as the direction of valve core movement, which promotes valve opening and improves response efficiency. The valve core also has a cavity added to the return oil passage. The resultant force of the oil on the cavity is in the same direction as the direction of valve core movement, which promotes valve opening and improves response efficiency.

[0034] 7. The servo valve of the present invention further includes a reset structure, which is located at the end of the valve core away from the motor. The reset structure can provide a reset force to the valve core. The position of the reset structure facilitates installation and debugging. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the motor structure according to Embodiment 1 of the present invention;

[0036] Figure 2 for Figure 1 Enlarged view of part A;

[0037] Figure 3 for Figure 1 BB cross-section;

[0038] Figure 4 This is a schematic diagram of the coil assembly.

[0039] Figure 5 A schematic diagram of the structure in which the sensing components are mounted on the housing;

[0040] Figure 6 This is a front view of the induction coil mounted on the PCB board.

[0041] Figure 7 This is a side view of the induction coil mounted on the PCB board.

[0042] Figure 8 This is a schematic diagram of the servo valve according to Embodiment 1 of the present invention;

[0043] Figure 9 A schematic diagram of the valve assembly and reset structure;

[0044] Figure 10 This is a partial structural diagram of the valve core;

[0045] Figure 11 for Figure 10 A force diagram of the structure shown;

[0046] Figure 12 This is a schematic diagram of the motor structure according to Embodiment 2 of the present invention;

[0047] Figure 13 This is a schematic diagram of the motor structure according to Embodiment 3 of the present invention;

[0048] Figure 14 This is a schematic diagram of the structure of an outer annular radial permanent magnet;

[0049] Figure 15 This is a schematic diagram of the structure of an inner annular radial permanent magnet;

[0050] In the diagram: 1-Outer shell; 11-Housing shell; 111-Fixed bushing; 112-Partially narrowed opening; 12-End cap; 13-Screw plug; 2-Magnetic assembly; 21-Outer ring magnetic assembly; 211, 211a, 211b, 211c, 211d-Outer annular axial permanent magnets; 212, 212a, 212b, 212c, 212d-Outer annular magnetic conductors; 213, 213a, 213b, 213c, 213d-Outer annular radial permanent magnets 22-Inner ring magnetic assembly; 221, 221a, 221b, 221c, 221d-Inner cylindrical axial permanent magnet; 222, 222a, 222b, 222c-Inner cylindrical magnetic conductor; 223, 223a, 223b, 223c-Inner annular radial permanent magnet; 23-Magnetic conductor block; 24-Outer support sleeve; 25-Inner support sleeve; 3-Coil assembly; 31-Coil frame; 311-Mounting structure; 3111-Mounting Cylinder; 3112-Mounting shaft; 312-Wire routing section; 32-Winding; 321-Second cable assembly; 4-Sensing assembly; 41-Induction core; 42-Induction coil; 421-Frame section; 422-Coil section; 4221-First cable assembly; 43-PCB board; 431-Inner end; 4311-Through hole; 4312-Allowing hole; 432-Outer end; 5-Valve assembly; 51-Valve body; 511-Pressure oil passage; 512-Working oil passage ; 513-Return oil passage; 52-Valve core; 521-Flow groove; 522-Shoulder; 523-Annular groove; 524-Cavity; 525-Cylindrical pin; 53-Valve sleeve; 531-Pressure oil port; 532-Working oil port; 533-Return oil port; 534-Outer expansion; 6-Reset structure; 61-Inner spring; 62-Outer spring; 63-Large spring seat; 64-Small spring seat; 65-End cap; 7-Connecting pin; 8-Elastic element; 9-Controller. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0053] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0054] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0055] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0056] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0057] Example 1

[0058] like Figure 1-7 As shown, this embodiment provides a motor, including a housing 1, a magnetic assembly 2, and a coil assembly 3. The magnetic assembly 2 is assembled inside the housing 1 and generates magnetic field lines. The coil assembly 3 is movably assembled. When energized, the coil assembly 3 can move axially to provide a driving function.

[0059] like Figure 1 As shown, the outer shell 1 can be an open-end structure, or it can be a split structure. The outer shell 1 includes a housing 11, an end cap 12, and a screw plug 13. The housing 11 is a cylindrical structure with open ends. The end cap 12 is fitted to one end of the housing 11. The end cap 12 is ring-shaped and can be inserted into the end of the housing 11 to block the outer ring magnetic assembly 21 of the magnetic assembly 2. The central hole of the end cap 12 facilitates the insertion of the inner ring magnetic assembly 22 of the magnetic assembly 2. The screw plug 13 is inserted into the central hole of the end cap 12 and can block the inner ring magnetic assembly 22 of the magnetic assembly 2.

[0060] As a preferred embodiment, a stepped surface is formed inside the housing 11. After the outer magnetic assembly 21 is installed inside the housing 11, the stepped surface and the end cap 12 can cooperate to axially limit the outer magnetic assembly 21. A partial constriction 112 is also formed inside the housing 11, such as... Figure 1 , 3 As shown, the partial constriction 112 can cooperate with the screw plug 13 to axially limit the inner ring magnetic assembly 22.

[0061] As a preferred technical solution in this embodiment, the housing 11, end cap 12 and screw plug 13 are all made of soft magnetic material.

[0062] like Figure 1-3 As shown, the magnetic assembly 2 is assembled inside the housing 1. The magnetic assembly 2 includes an outer magnetic assembly 21 and an inner magnetic assembly 22 arranged at intervals, forming an annular space between the outer magnetic assembly 21 and the inner magnetic assembly 22. The outer magnetic assembly 21 is formed by alternating axial arrangements of annular permanent magnets and annular magnetic conductors; the inner magnetic assembly 22 is formed by alternating axial arrangements of cylindrical permanent magnets and cylindrical magnetic conductors.

[0063] As a preferred embodiment, the outer magnetic assembly 21 is formed by alternating axial arrangements of an outer annular axial permanent magnet 211 and an outer annular magnetic conductor 212, while the inner magnetic assembly 22 is formed by alternating axial arrangements of an inner cylindrical axial permanent magnet 221 and an inner cylindrical magnetic conductor 222. The outer annular axial permanent magnet 211 is located on the radial outer periphery of the inner cylindrical axial permanent magnet 221, and the outer annular magnetic conductor 212 is located on the radial outer periphery of the inner cylindrical magnetic conductor 222. Figure 3As shown, when there are four outer annular axial permanent magnets 211, they are specifically outer annular axial permanent magnets 211a, 211b, 211c, and 211d; and there are three outer annular magnetic conductors 212, specifically outer annular magnetic conductors 212a, 212b, and 212c. Along the direction from the end cap 12 to the stepped surface, the outer annular axial permanent magnet 211a, outer annular magnetic conductor 212a, outer annular axial permanent magnet 211b, outer annular magnetic conductor 212b, outer annular axial permanent magnet 211c, outer annular magnetic conductor 212c, and outer annular axial permanent magnet 211d are arranged in sequence; there are four inner cylindrical axial permanent magnets 221, specifically inner cylindrical axial permanent magnets 221a, 221b, 221c, and 221d; there are three inner cylindrical magnetic conductors 222, specifically inner cylindrical magnetic conductors 222a, 222b, and 222c. Along the direction from the screw plug 13 to the partial constriction 112, the inner cylindrical axial permanent magnets 221a, 222a, 221b, 222b, 221c, 222c, and 221d are arranged sequentially. The inner cylindrical axial permanent magnets 221a are spaced within the inner circumference of the outer annular axial permanent magnets 211a; the inner cylindrical axial permanent magnets 221b are spaced within the inner circumference of the outer annular axial permanent magnets 211b; the inner cylindrical axial permanent magnets 221c are spaced within the inner circumference of the outer annular axial permanent magnets 211c; and the inner cylindrical axial permanent magnets 221d are spaced within the inner circumference of the outer annular axial permanent magnets 211d. The inner cylindrical magnetic conductors 222a are spaced apart within the inner circumference of the outer annular magnetic conductors 212a, the inner cylindrical magnetic conductors 222b are spaced apart within the inner circumference of the outer annular magnetic conductors 212b, and the inner cylindrical magnetic conductors 222c are spaced apart within the inner circumference of the outer annular magnetic conductors 212c. This arrangement, together with the outer shell 1 and the magnetic block 23, forms four sets of annular magnetic field lines. Besides the above-mentioned quantity settings, the outer annular axial permanent magnets 211, outer annular magnetic conductors 212, inner cylindrical axial permanent magnets 221, and inner cylindrical magnetic conductors 222 can also be set to other quantities, as long as the quantities of the outer annular axial permanent magnets 211 and inner cylindrical axial permanent magnets 221 are the same, and the quantities of the outer annular magnetic conductors 212 and inner cylindrical magnetic conductors 222 are the same.

[0064] As a preferred technical solution of this embodiment, the magnetization directions of the two axially adjacent outer annular axial permanent magnets 211 are opposite, that is, the magnetic field lines generated by the two axially adjacent outer annular axial permanent magnets 211 are opposite; the magnetization directions of the two axially adjacent inner cylindrical axial permanent magnets 221 are opposite, that is, the magnetic field lines generated by the two axially adjacent inner cylindrical axial permanent magnets 221 are opposite; the magnetization directions of the outer annular axial permanent magnets 211 and the inner cylindrical axial permanent magnets 221 are opposite, that is, the magnetic field lines generated by the outer annular axial permanent magnets 211 and the inner cylindrical axial permanent magnets 221 are opposite.

[0065] As a preferred embodiment, the magnetic assembly 2 further includes a magnetic guide block 23, which is located between the inner magnetic assembly 22 and the partial constriction 112. The magnetic guide block 23 abuts against the partial constriction 112, and the magnetic guide block 23 and the screw plug 13 are located on opposite axial sides of the inner magnetic assembly 22.

[0066] As a preferred technical solution of this embodiment, the magnetic assembly 2 further includes an outer support sleeve 24, which is placed inside the housing 11, and the outer ring magnetic assembly 21 is constrained within the outer support sleeve 24.

[0067] As a preferred technical solution in this embodiment, the magnetic assembly 2 further includes an inner support sleeve 25, and the inner magnetic assembly 22 is constrained within the inner support sleeve 25.

[0068] As a preferred technical solution in this embodiment, the outer support sleeve 24 and the inner support sleeve 25 are made of non-magnetic material.

[0069] like Figure 1-4 As shown, the coil assembly 3 is movably installed within the annular space. When energized, the coil assembly 3 moves axially. The coil assembly 3 includes a coil frame 31 and windings 32. The coil frame 31 is located between the outer magnetic group 21 and the inner magnetic group 22. The coil frame 31 is provided with windings 32, which can be configured in multiple groups. The windings 32 cut magnetic field lines between the outer magnetic group 21 and the inner magnetic group 22, generating an output force.

[0070] As a preferred embodiment, one end of the coil frame 31 has a mounting structure 311 for easy connection to the driven structure. Specifically, the mounting structure 311 is located at the end of the coil frame 31 furthest from the end cap 12. The mounting structure 311 includes a mounting cylinder 3111 formed by a partial extension of the coil frame 31. The mounting cylinder 3111 is located on the axis of the motor. A mounting shaft 3112 is inserted into the mounting cylinder 3111. One end of the mounting shaft 3112 is inserted into the mounting cylinder 3111, and the other end of the mounting shaft 3112 extends out of the mounting cylinder 3111 to connect to the driven structure. Preferably, the coil frame 31 has a partial constriction 112, and the mounting cylinder 3111 is located on the side of the partial constriction 112 closer to the adjacent opening. Specifically, one end of the coil frame 31 has a radially extending portion, and the mounting cylinder 3111 extends from the radially extending portion.

[0071] As a preferred embodiment, one end of the coil frame 31 further extends to form a wiring portion 312, which is located on the outer periphery of the mounting cylinder 3111 to facilitate the routing of the cable of the winding 32. Preferably, the wiring portion 312 extends parallel to the axis from the radial extension portion, and the axial extension length of the wiring portion 312 is greater than the axial extension length of the mounting cylinder 3111.

[0072] As a preferred embodiment, the number of windings 32 can be multiple, with adjacent windings 32 having opposite winding directions, ensuring that the Ampere force generated by the current cutting the magnetic field lines in all windings 32 has the same direction. The number of windings 32 is one less than the number of outer annular axial permanent magnets 211. By changing the direction and magnitude of the current in the windings 32, the direction and magnitude of the Ampere force experienced by the coil assembly 3 can be changed. In this embodiment, the number of windings 32 in the coil assembly 3 is three.

[0073] like Figure 1 , 3 As shown in Figure 5-7, the sensing component 4 senses the movement of the coil assembly 3, and thus can sense the movement of the driven structure. The sensing component 4 includes a sensing core 41, a sensing coil 42, and a PCB board 43. The sensing core 41 moves with the coil assembly 3, and the sensing coil 42 cooperates with the sensing core 41 to sense. The PCB board 43 is fixedly mounted, and the sensing coil 42 is mounted on the PCB board 43. Both the coil assembly 3 and the sensing coil 42 are electrically connected to the PCB board 43, and traces are routed through the PCB board 43.

[0074] As a preferred technical solution in this embodiment, the sensing component 4 senses the movement of the mounting structure 311, and the sensing core 41 is disposed on the mounting structure 311. Specifically, the sensing core 41 is placed inside the mounting cylinder 3111 and is limited between the mounting shaft 3112 and the mounting cylinder 3111, that is, when the mounting shaft 3112 is inserted into the mounting cylinder 3111, the sensing core 41 is limited inside the mounting cylinder 3111.

[0075] As a preferred embodiment, the induction coil 42 is positioned on the outer periphery of the mounting cylinder 3111. The induction coil 42 includes a frame portion 421 and a coil portion 422. The frame portion 421 is used to connect with the PCB board 43, and the coil portion 422 is mounted on the frame portion 421.

[0076] As a preferred embodiment, the PCB board 43 includes an inner end 431 and an outer end 432. The inner end 431 is placed inside the housing 11, near the opening of the housing 11, and the outer edge of the inner end 431 is in contact with the inner wall of the housing 11. The outer end 432 extends out of the housing 11. Specifically, an axial notch can be formed on the housing 11 corresponding to the outer end 432. The PCB board 43 is axially pushed in, with its inner end 431 in contact with the inner wall of the housing 11 and its outer end 432 fitting into the axial notch, thereby achieving radial positioning of the PCB board 43. Furthermore, by setting a fixing bushing 111 at the opening of the housing 11, the fixing bushing 111 and the axial notch can cooperate to axially position the PCB board 43, thus achieving the installation of the PCB board 43.

[0077] As a preferred technical solution in this embodiment, the inner end 431 of the PCB board 43 is ring-shaped, and a through hole 4311 is formed in the middle of the inner end 431. The through hole 4311 is coaxially arranged with the mounting structure 311, and the mounting structure 311 passes through the through hole 4311. The diameter of the through hole 4311 is larger than the outer diameter of the mounting structure 311.

[0078] As a preferred technical solution in this embodiment, the skeleton part 421 of the induction coil 42 is attached to the PCB board 43, and the fastener can fix the skeleton part 421 to the PCB board 43. The coil part 422 of the induction coil 42 is located in the through hole 4311 and is directly opposite to the induction iron core 41 in the mounting cylinder 3111.

[0079] As a preferred embodiment, the connection point of the PCB board 43 is located on the surface away from the magnetic assembly 2. Both the cable of the winding 32 and the cable of the induction coil 42 are connected to the connection point on the inner end 431 of the PCB board 43. Specifically, a clearance hole 4312 is also formed on the inner end 431 of the PCB board 43 to facilitate the passage of the wiring portion 312. The second cable assembly 321 of the winding 32 reaches the side of the PCB board 43 away from the magnetic assembly 2 via the wiring portion 312 and connects to the connection point on the inner end 431 of the PCB board 43. The first cable assembly 4221 of the coil portion 422 passes through the frame portion 421 to reach the side of the PCB board 43 away from the magnetic assembly 2 and connects to the connection point on the inner end 431 of the PCB board 43. There are also wiring traces inside the PCB board 43, such as... Figure 6As shown, the internal wiring of the PCB board 43 is indicated by dashed lines. Preferably, because the coil assembly 3 needs to reciprocate axially, the second cable assembly 321 with the winding 32 has a larger length on the side of the PCB board 43 away from the magnetic assembly 2, reducing the damage caused by the pulling of the wire connection points due to frequent reciprocating linear motion.

[0080] like Figure 8-11 As shown, this embodiment also provides a servo valve, including the aforementioned motor, and also includes a valve assembly 5. The valve assembly 5 includes a valve core 52, which serves as a driven structure and moves under the drive of the motor.

[0081] like Figure 9 As shown, the valve assembly 5 includes a valve body 51, a valve core 52, and a valve sleeve 53. The valve body 51 has an installation hole and multiple oil passages. The valve sleeve 53 is installed in the installation hole. The valve core 52 is slidably assembled in the valve sleeve 53. The sliding of the valve core 52 controls the opening and closing of the oil passages.

[0082] As a preferred technical solution in this embodiment, the mounting hole is a through hole that penetrates the valve body 51 and is located on the axis of the motor.

[0083] As a preferred embodiment, the valve body 51 contains multiple oil passages, including a pressure oil passage 511, a working oil passage 512, and a return oil passage 513, all of which are connected to the mounting hole. The pressure oil passage 511 is used to introduce pressure oil; there are two working oil passages 512, arranged on both sides of the pressure oil passage 511; the return oil passage 513 extends to both sides of the working oil passage 512 and is connected to the mounting hole.

[0084] As a preferred technical solution in this embodiment, the valve body 51 and the housing 11 at the end away from the end cap 12 can axially limit the fixed bushing 111.

[0085] As a preferred embodiment, the valve sleeve 53 has multiple oil ports corresponding to multiple oil passages. Specifically, the valve sleeve 53 has a pressure oil port 531, a working oil port 532, and a return oil port 533. There is one pressure oil port 531, which is connected to the pressure oil passage 511; there are two working oil ports 532, which are respectively connected to two working oil passages 512; and there are two return oil ports 533, which are connected to the return oil passage 513. The valve core 52 can control the flow of oil passages by controlling the opening and closing of the oil ports.

[0086] As a preferred technical solution in this embodiment, the valve core 52 is slidably assembled in the valve sleeve 53. The valve core 52 is provided with a flow groove 521 corresponding to the two working oil ports 532. The two flow grooves 521 are connected to the two working oil ports 532. When in the middle position, the oil ports are not connected to each other. When the valve core 52 moves to the two working positions, one working oil port 532 is connected to the pressure oil port 531 through the corresponding flow groove 521, and the other working oil port 532 is connected to the return oil port 533 through the corresponding flow groove 521.

[0087] As a preferred technical solution in this embodiment, such as Figure 10 As shown, a shoulder 522 is provided inside the flow channel 521. The shoulder 522 divides the flow channel 521 into two parts. When the valve core 52 slides to the first working position ( Figure 9-10 When the oil is in the left position (as shown in the image), the oil in the working oil passage 512 on the left side reaches the corresponding flow groove 521 through the corresponding working oil port 532, and then passes through the flow groove 521 on the left side of the shoulder 522 to reach the adjacent return oil port 533. The flow direction of the oil is as follows: Figure 10 As shown, according to Bernoulli's equation, neglecting energy loss, the fluid pressure decreases as the fluid velocity increases. The right side of shoulder 522 is a non-flowing cavity with a velocity of almost zero. Therefore, the pressure on the right side of shoulder 522 is greater than the pressure on the left side. Figure 11 As shown, P4 > P3, F4 > F3, and the resultant force direction of shoulder 522 is the same as the movement direction of valve core 52, promoting valve opening and improving response time. Similarly, when valve core 52 slides to the second working position ( Figure 9 When the valve is in the right position, the resultant force of the shoulder 522 in the flow groove 521 on the right side is in the same direction as the movement direction of the valve core 52.

[0088] As a preferred technical solution in this embodiment, such as Figure 10 As shown, the valve core 52 also forms cavities 524 corresponding to the two return oil ports 533. Specifically, the valve core 52 is provided with annular grooves 523 corresponding to the two return oil ports 533, and the portion of the annular grooves 523 located outside the return oil ports 533 can form cavities 524. Preferably, the valve sleeve 53 can be provided with an outwardly expanding portion 534 around the return oil ports 533, and the portion of the annular grooves 523 located outside the return oil ports 533 and the corresponding outwardly expanding portion 534 cooperate to form cavities 524. Figure 10 As shown, when the valve core 52 slides to the first working position ( Figure 9-10 When the fluid flows to the left side of cavity 524 (as shown in the left position), the oil does not flow through the left side of cavity 524, and eddies will be generated on the right side of cavity 524. According to Bernoulli's equation, neglecting energy loss, the fluid pressure decreases as the fluid velocity increases. The oil velocity on the left side of the cavity is almost zero, resulting in higher pressure. Figure 11P1 > P2, F1 > F2, and the resultant force is in the same direction as the movement direction of valve core 52, which promotes valve opening and improves response time.

[0089] The valve core 52 is driven to move by a motor, and the end of the valve core 52 near the motor is connected to the mounting structure 311. Specifically, the end of the mounting shaft 3112 extending out of the mounting cylinder 3111 has a blind hole, and the end of the valve core 52 is inserted into the blind hole of the mounting shaft 3112. Corresponding connecting holes are formed on the mounting shaft 3112 and the valve core 52. The connecting pin 7 passes through the connecting holes of the mounting shaft 3112 and the valve core 52 to connect the mounting shaft 3112 and the valve core 52 together.

[0090] As a preferred embodiment, the connecting pin 7 and the connecting hole on the mounting shaft 3112 are interference-fitted, and the connecting pin 7 and the connecting hole on the valve core 52 are also interference-fitted. The connecting pin 7 can be, but is not limited to, a cylindrical pin, and a groove can be provided on the cylindrical pin.

[0091] As a preferred embodiment, an elastic element 8 is further provided between the valve core 52 and the mounting shaft 3112, such as... Figure 9 As shown, the end of the valve core 52 also has a stepped surface. When the end of the valve core 52 is inserted into the mounting shaft 3112, the annular end face of the mounting shaft 3112 can abut against the stepped surface of the end of the valve core 52. The elastic element 8 is placed between the annular end face of the mounting shaft 3112 and the stepped surface of the end of the valve core 52. The elastic element 8 can be, but is not limited to, a disc spring.

[0092] like Figure 8 As shown, a reset structure 6 is provided at the end of the valve assembly 5 furthest from the motor. The reset structure 6 acts on the valve core 52, providing a reset force to the valve core 52. Figure 9 As shown, the reset structure 6 includes an inner spring 61 and an outer spring 62, which provide opposite reset forces to the valve core 52. The reset structure 6 also includes two spring seats and an end cap 65. The end cap 65 is sealed and fitted onto the side of the valve body 51 away from the motor, sealing the opening of the mounting hole and covering the end of the valve core 52. The two spring seats are a large spring seat 63 and a small spring seat 64, which are slidably fitted onto the valve core 52. The two ends of the inner spring 61 act on the large spring seat 63 and the small spring seat 64, respectively. The outer spring 62 is fitted around the outer periphery of the inner spring 61, with one end acting on the large spring seat 63 and the other end acting on the inner wall of the end cap 65.

[0093] As a preferred technical solution in this embodiment, the inner spring 61 and the outer spring 62 have the same elastic stiffness, so the inner spring 61 and the outer spring 62 provide the same reset force to the valve core 52.

[0094] As a preferred technical solution in this embodiment, the outer peripheral surface of the end of the valve core 52 is formed with a stepped surface, which can be used to limit the large spring seat 63; the end of the valve core 52 is also provided with a cylindrical pin 525, which is closer to the end face of the valve core 52 than the stepped surface, and the cylindrical pin 525 can be used to limit the small spring seat 64.

[0095] As a preferred technical solution in this embodiment, such as Figure 4-5 As shown, the outer radial end of the large spring seat 63 extends axially toward the valve sleeve 53 with an outer edge, on which a countersunk hole is formed. When the motor is not outputting force, the outer spring 62 is at its maximum length, and the outer edge of the large spring seat 63 abuts against the valve sleeve 53. Under the action of the inner spring 61, the gap between the radial inner end of the large spring seat 63 and the stepped surface of the valve core 52 becomes 0, and there is a certain opening between the valve core 52 and the valve sleeve 53. This opening is the valve core opening degree of the servo valve in the power-off safety position. By adjusting the size of the gap (i.e., adjusting the axial dimension of the countersunk hole of the large spring seat 63), the opening direction and size of the servo valve in the power-off safety position can be easily adjusted. At the same time, using machining dimensions to control the size of this opening can improve the consistency of different batches of products and facilitate quality control in the production process. When the motor outputs thrust, the valve core 52 pushes against the large spring seat 63 and moves toward the end cover 65. The inner spring 61 is at its maximum length, the large spring seat 63 compresses the outer spring 62, and the valve core 52 moves against the force of the outer spring 62. After the motor stops working, the valve core 52 can return to a safe position under the force of the outer spring 62. When the motor outputs pulling force, the large spring seat 63 abuts against the valve sleeve 53, and the cylindrical pin 525 on the valve core 52 pushes the small spring seat 64 away from the end cover 65. The outer spring 62 is at its maximum length, and the small spring seat 64 compresses the inner spring 61. The valve core 52 moves against the force of the inner spring 61. After the motor stops working, the valve core 52 can return to a safe position under the force of the inner spring 61.

[0096] The servo valve also includes a controller 9, which is electrically connected to the PCB board 43. The controller 9 can be positioned close to the PCB board 43. The controller 9 can control the magnitude and direction of the current in the coil portion 422 of the induction coil 42; the controller 9 can also control the magnitude and direction of the current in the winding 32. The controller 9 also receives the position signal from the mounting structure 311 fed back by the induction coil 42, i.e., the position signal of the valve core 52. The controller 9 adjusts the current in the winding 32 in real time according to the position signal to perform closed-loop control of the movement of the valve core 52.

[0097] Based on the above technical solution, the servo valve in this embodiment has a sensing component 4 installed at the connection between the motor and the valve core 52. This eliminates the need to increase the axial length of the servo valve, facilitating its installation. The sensing component 4 includes an induction core 41, an induction coil 42, and a PCB board 43. The PCB board 43 not only meets the circuit routing requirements and facilitates oil sealing but also allows for the assembly of the induction coil 42, resulting in a compact motor structure. The mounting structure 311 of the induction core 41 and the coil frame 31 is integrated, achieving lightweight and miniaturized displacement detection. The dual-induction coil half-bridge displacement sensor, composed of the induction core 41, induction coil 42, and PCB board 43, is smaller in size than the LVDT sensor commonly used in proportional valves. Furthermore, a bridge method is employed to improve sensitivity, linearity, common-mode interference immunity, and temperature stability.

[0098] Example 2

[0099] like Figure 12 As shown, this embodiment is basically the same as Embodiment 1, except that the outer support sleeve 24 is removed, the outer annular axial permanent magnet 211 and the outer annular magnetic conductor 212 can be enlarged, and are limited by the inner wall of the housing 11; the material of the housing 11 is changed to a non-magnetic material to improve the motor output force; the number of outer annular magnetic conductors 212 is increased, such as... Figure 12 As shown, an outer ring magnetic conductor 212d is added. The outer ring magnetic conductor 212d is located on the outer periphery of the magnetic conductor block 23 to reduce magnetic leakage.

[0100] Example 3

[0101] like Figure 13 As shown, this embodiment is basically the same as embodiment two, except that the outer annular magnetic conductor 212 is replaced by an outer annular radial permanent magnet 213, and the outer ring magnetic assembly 21 is formed by alternating axial arrangement of the outer annular axial permanent magnet 211 and the outer annular radial permanent magnet 213; the inner cylindrical magnetic conductor 222 is replaced by an inner annular radial permanent magnet 223, and the inner ring magnetic assembly 22 is formed by alternating axial arrangement of the inner cylindrical axial permanent magnet 221 and the inner annular radial permanent magnet 223.

[0102] As a preferred technical solution of this embodiment, the outer annular axial permanent magnet 211 is located on the radial outer periphery of the inner cylindrical axial permanent magnet 221, and the outer annular radial permanent magnet 213 is located on the radial outer periphery of the inner annular radial permanent magnet 223.

[0103] As a preferred embodiment, the magnetization directions of two axially adjacent outer annular radial permanent magnets 213 are opposite, meaning the magnetic field lines generated by the two axially adjacent outer annular radial permanent magnets 213 are in opposite directions; similarly, the magnetization directions of two axially adjacent inner annular radial permanent magnets 223 are also opposite, meaning the magnetic field lines generated by the two axially adjacent inner annular radial permanent magnets 223 are in opposite directions. The magnetization direction of the outer annular radial permanent magnet 213 is the same as that of the inner annular radial permanent magnet 223, meaning the magnetic field lines generated by the outer annular radial permanent magnet 213 and the inner annular radial permanent magnet 223 are in the same direction. The magnetization direction of the outer annular radial permanent magnet 213 corresponds to the magnetization direction of the adjacent outer annular axial permanent magnet 211; the magnetization direction of the inner annular radial permanent magnet 223 corresponds to the magnetization direction of the adjacent inner cylindrical axial permanent magnet 221.

[0104] As a preferred technical solution in this embodiment, specifically, as follows: Figure 13 As shown, for the outer ring magnetic assembly 21, the outer annular magnetic conductors 212a, 212b, 212c, and 212d are replaced with outer annular radial permanent magnets 213a, 213b, 213c, and 213d. Along the direction from the end cap 12 to the stepped surface, the outer annular axial permanent magnets 211a, 213a, 211b, 213b, 211c, 213c, 211d, and 213d are arranged sequentially. For the inner ring magnetic assembly 22, the inner cylindrical magnetic conductors 222a, 222b, and 222c are replaced with inner annular radial permanent magnets 223a, 223b, and 223c. Along the direction from the screw plug 13 to the partial constriction 112, the inner cylindrical axial permanent magnets 221a, 223a, 221b, 223b, 221c, 223c, and 221d are arranged sequentially.

[0105] As a preferred technical solution in this embodiment, manufacturing a complete radially magnetized annular permanent magnet is quite difficult. To achieve radial magnetization, the annular permanent magnet can be divided into several sector-shaped pieces, which are then produced separately, magnetized, and assembled into a radially magnetized permanent magnet. For example... Figure 14 As shown, the outer annular radial permanent magnet 213a can be produced by dividing a larger annular permanent magnet into several sectors, then producing and magnetizing them separately before assembling them into a radially outward magnetized permanent magnet; as shown... Figure 15As shown, the inner annular radial permanent magnet 223a can be assembled into a radially outward magnetized permanent magnet by dividing a smaller annular permanent magnet into several sectors, producing them separately, magnetizing them, and then assembling them.

[0106] As a preferred technical solution in this embodiment, the housing 11 is made of a magnetically conductive material.

[0107] In this embodiment, the motor and servo valve, the magnetic assembly 2 adopts the superposition of radial permanent magnet and axial permanent magnet magnetic fields, which improves the magnetic field strength passing through the winding 32, and further improves the output force of the motor.

[0108] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An electric motor, characterized in that, include: Outer shell (1); The magnetic assembly (2) is installed inside the housing (1). The magnetic assembly (2) includes an outer ring magnetic assembly (21) and an inner ring magnetic assembly (22) arranged at intervals. An annular space is formed between the outer ring magnetic assembly (21) and the inner ring magnetic assembly (22). The coil assembly (3) is movably installed in the annular space. When the coil assembly (3) is energized, the coil assembly (3) moves along the axial direction. The coil assembly (3) includes a coil frame (31) and a winding (32). One end of the coil frame (31) forms a mounting structure (311) to connect to the driven structure. The sensing component (4) senses the movement of the mounting structure (311). The sensing component (4) includes an induction core (41), an induction coil (42), and a PCB board (43). The induction core (41) moves with the mounting structure (311). The induction coil (42) is mounted on the PCB board (43) and cooperates with the induction core (41) to sense. The coil assembly (3) and the induction coil (42) are both electrically connected to the PCB board (43).

2. The motor according to claim 1, characterized in that, One end of the coil frame (31) extends to form a mounting cylinder (3111), the mounting cylinder (3111) is located on the axis of the motor, the mounting cylinder (3111) is connected to a mounting shaft (3112), the induction core (41) is limited and installed between the mounting shaft (3112) and the mounting cylinder (3111), and the gap of the induction coil (42) is placed on the outer periphery of the mounting cylinder (3111).

3. The motor according to claim 1, characterized in that, The inner end (431) of the PCB board (43) is placed inside the outer shell (1), the outer edge of the inner end (431) of the PCB board (43) is attached to the inner wall of the outer shell (1), and the outer end of the PCB board (43) extends out of the outer shell (1).

4. The motor according to claim 3, characterized in that, The inner end (431) of the PCB board (43) has a through hole (4311), the through hole (4311) is coaxially arranged with the mounting structure (311), the mounting structure (311) passes through the through hole (4311), the skeleton part of the induction coil (42) is fixedly connected to the PCB board (43), and the coil part of the induction coil (42) is placed in the through hole (4311).

5. The motor according to claim 1, characterized in that, The connection point of the PCB board (43) is located on the surface away from the magnetic assembly (2). The coil frame (31) also extends with a wiring section (312). The wiring section (312) passes through the PCB board (43). The cable of the winding (32) reaches the side of the PCB board (43) away from the magnetic assembly (2) through the wiring section (312).

6. The motor according to claim 1, characterized in that, The outer ring magnetic assembly (21) is formed by alternating axial arrangement of an outer ring axial permanent magnet (211) and an outer ring magnetic conductor (212), and the inner ring magnetic assembly (22) is formed by alternating axial arrangement of an inner cylindrical axial permanent magnet (221) and an inner cylindrical magnetic conductor (222). or, The outer ring magnetic assembly (21) is formed by alternating axial arrangement of outer ring axial permanent magnets (211) and outer ring radial permanent magnets (213), and the inner ring magnetic assembly (22) is formed by alternating axial arrangement of inner cylindrical axial permanent magnets (221) and inner ring radial permanent magnets (223). The magnetization directions of adjacent outer ring axial permanent magnets (211) are opposite, the magnetization directions of adjacent outer ring radial permanent magnets (213) are opposite, the magnetization directions of adjacent inner cylindrical axial permanent magnets (221) are opposite, and the magnetization directions of adjacent inner ring radial permanent magnets (223) are opposite.

7. A servo valve, characterized in that, include: The motor according to any one of claims 1-6; The valve assembly (5) includes a valve body (51) and a valve core (52), the valve core (52) moving under the drive of the motor; The controller (9) is electrically connected to the PCB board (43).

8. A servo valve according to claim 7, characterized in that, The end of the valve core (52) is inserted into the end of the mounting structure (311), and the connecting pin (7) passes through the end of the valve core (52) and the mounting structure (311) to connect the two together. An elastic element (8) is also provided between the valve core (52) and the mounting structure (311).

9. A servo valve according to claim 7, characterized in that, The valve body (51) is provided with a pressure oil passage (511), a working oil passage (512) and a return oil passage (513). The valve core (52) is provided with a flow groove (521) corresponding to the working oil passage (512), and a shoulder (522) is formed in the flow groove (521). The valve core (52) is provided with a cavity (524) corresponding to the return oil passage (513).

10. A servo valve according to claim 7, characterized in that, A reset structure (6) is provided at the end of the valve core (52) away from the motor.

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