Proportional valve

Abstract

The utility model relates to the technical field of hydraulic systems, in particular to a proportional valve. The proportional valve comprises a flux sleeve, a moving iron and a lubricating piece, the moving iron is movably arranged in the flux sleeve in a penetrating mode, the lubricating piece is located in a radial gap between the flux sleeve and the moving iron, and the moving iron can move in the axial direction of the flux sleeve relative to the lubricating piece. According to the proportional valve provided by the utility model, the lubricating piece is arranged in the radial gap between the flux sleeve and the moving iron, so that the moving iron moves along the axial direction of the flux sleeve relative to the lubricating piece, the relative friction force between the moving iron and the lubricating piece is greatly reduced, and the proportional valve has the advantages of small hysteresis and high precision; and the lubricating piece can keep low friction performance for a long time, and hysteresis deterioration of the proportional valve is avoided. In addition, the lubricating piece is arranged to reduce the friction resistance when the moving iron moves, the requirement for the machining precision of the moving iron and the flux sleeve is lowered, the machining cost is reduced, and the machining efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic systems, in particular to a proportional valve. Background Art

[0002] The proportional valve provided in the related art needs to reduce the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, so as to reduce the friction force of the moving iron when it moves relative to the magnetic sleeve in the magnetic sleeve, so that the proportional valve has the advantages of small hysteresis and high precision. However, in order to reduce the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, the processing accuracy requirements for the magnetic sleeve and the moving iron are greatly increased, which increases the processing cost and reduces the processing efficiency. In addition, after long-term use of the proportional valve, due to the mechanical contact between the moving iron and the magnetic sleeve, the moving iron and the magnetic sleeve will cause mutual wear, resulting in an increase in the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, thereby increasing the friction force of the moving iron when it moves relative to the magnetic sleeve in the magnetic sleeve, making the hysteresis of the proportional valve worse.

[0003] Therefore, a proportional valve is urgently needed to solve the above problems. Utility Model Content

[0004] The purpose of the utility model is to provide a proportional valve, so that the proportional valve has the advantages of small hysteresis and high precision, can also avoid the hysteresis of the proportional valve from deteriorating, and can reduce the processing accuracy requirements for the moving iron and the magnetic sleeve, reduce processing costs, and improve processing efficiency.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A proportional valve, comprising:

[0007] Magnetic sleeve;

[0008] a moving iron, the moving iron being movably disposed in the magnetic conductive sleeve; and

[0009] A lubricating member is located in a radial gap between the magnetic sleeve and the movable iron, and the movable iron can move along the axial direction of the magnetic sleeve relative to the lubricating member.

[0010] As an optional solution, the lubricating component includes a base material and a coating layer coated on the outer surface of the base material, the base material is made of glass fiber material, and the coating layer is made of polytetrafluoroethylene material.

[0011] As an optional solution, a mounting cavity is provided inside the magnetic conductive sleeve, and the proportional valve further includes a first limiter, the first limiter is fixed in the inner cavity wall of the mounting cavity, the movable iron is movably provided in the mounting cavity, and the movable iron can pass through the first limiter;

[0012] Two ends of the lubricating member along the axial direction of the magnetic conductive sleeve are respectively in contact with the bottom wall of the installation cavity and the first limiting member.

[0013] As an optional solution, a mounting groove is provided on the inner wall of the mounting cavity, and the first limiting member includes:

[0014] an elastic circlip fixed in the mounting groove; and

[0015] A limiting ring is clamped between the elastic retaining ring and the lubricating component.

[0016] As an optional solution, the proportional valve further includes:

[0017] A coil, wherein the coil is fixedly sleeved on the outer periphery of the magnetic sleeve;

[0018] a valve sleeve, the valve sleeve being fixedly connected to the end of the magnetic sleeve, and the valve sleeve being provided with a first port and a second port;

[0019] a main valve core, the main valve core being slidably disposed in the valve sleeve, the main valve core being capable of connecting the first port and the second port or blocking the first port and the second port;

[0020] a pilot valve core, one end of which is connected to the end of the movable iron, the other end of which is capable of abutting against the main valve core, and the pilot valve core is capable of driving the main valve core to slide to a position that blocks the first port and the second port; and

[0021] An elastic member is located between the magnetic sleeve and the movable iron, and the elastic member is configured to always have a tendency to drive the movable iron to move toward the pilot valve core and enable the pilot valve core to drive the main valve core to move.

[0022] As an optional solution, the outer wall of the main valve core is provided with an oil inlet groove connected to the second port. When the moving iron drives the pilot valve core to move in a direction away from the pilot valve core, the hydraulic oil entering the oil inlet groove through the second port can drive the main valve core to slide toward the position connecting the first port and the second port.

[0023] As an optional solution, the proportional valve further includes:

[0024] A second limit member is fixed in the inner wall of the installation cavity, and the second limit member can abut against the main valve core to limit the main valve core from sliding toward the position that guides the first port and the second port.

[0025] As an optional solution, a connecting cavity is provided in the moving iron and extends through the moving iron along its axial direction. The connecting cavity is connected to the mounting cavity. An oil inlet cavity is formed between the pilot valve core and the main valve core. The oil inlet cavity is connected to the connecting cavity, and the oil inlet cavity is connected to the second port.

[0026] As an optional solution, a radial oil inlet hole is provided on the outer peripheral wall of the main valve core, and the radial oil inlet hole connects the second port and the oil inlet chamber; an axial oil inlet hole is provided on the end of the main valve core, and the axial oil inlet hole can connect the first port and the oil inlet chamber, and when the other end of the pilot valve core abuts against the main valve core, the other end of the pilot valve core blocks the axial oil inlet hole.

[0027] As an optional solution, magnetic isolation copper is provided on the magnetic conductive sleeve.

[0028] Beneficial effects of the utility model:

[0029] The utility model provides a proportional valve. By providing a lubricating element in the radial gap between a magnetic sleeve and a movable iron, the movable iron moves axially relative to the lubricating element along the magnetic sleeve, significantly reducing the relative friction between the movable iron and the lubricating element. This results in a proportional valve with low hysteresis and high precision. Furthermore, the lubricating element can maintain low friction over a long period of time, thus preventing deterioration in the hysteresis performance of the proportional valve. Furthermore, by providing the lubricating element to reduce frictional resistance during movable iron movement, the machining precision requirements for the movable iron and the magnetic sleeve are reduced, thereby reducing machining costs and improving machining efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a cross-sectional view of the structure of the proportional valve provided by an embodiment of the utility model;

[0031] Figure 2 This is a schematic structural diagram of a lubricating component provided by an embodiment of the present utility model;

[0032] Figure 3 yes Figure 1 A magnified view of the structure at point A;

[0033] Figure 4 This is a structural cross-sectional view of the main valve core provided by an embodiment of the utility model;

[0034] Figure 5 It is a structural schematic diagram of the pilot valve core provided by an embodiment of the utility model.

[0035] In the picture:

[0036] 1. Magnetic guide sleeve; 11. Mounting cavity; 111. Mounting groove; 12. Magnetic insulation copper; 13. Connecting piece; 2. Moving iron; 21. Connecting cavity; 22. Abutting groove; 23. T-type connecting groove; 3. Lubricating piece; 31. First end; 32. Second end; 4. First limiting piece; 41. Elastic retaining ring; 42. Limiting ring; 5. Coil; 6. Valve sleeve; 61. First port; 62. Second port; 7. Main valve core; 71. Oil inlet groove; 72. Radial oil inlet hole; 73. Axial oil inlet hole; 8. Pilot valve core; 81. T-type connecting part; 82. Main body; 821. Connecting groove; 83. Abutting part; 9. Elastic piece; 10. Second limiting piece; 20. Locking nut; 30. Oil inlet cavity. DETAILED DESCRIPTION

[0037] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the present invention are further explained below with reference to the accompanying drawings and through specific implementation methods.

[0038] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0039] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on the positions or locations shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0041] The proportional valve provided in the related art needs to reduce the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, so as to reduce the friction force of the moving iron when it moves relative to the magnetic sleeve in the magnetic sleeve, so that the proportional valve has the advantages of small hysteresis and high precision. However, in order to reduce the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, the processing accuracy requirements for the magnetic sleeve and the moving iron are greatly increased, which increases the processing cost and reduces the processing efficiency. In addition, after long-term use of the proportional valve, due to the mechanical contact between the moving iron and the magnetic sleeve, the moving iron and the magnetic sleeve will cause mutual wear, resulting in an increase in the surface roughness of the inner cavity wall of the magnetic sleeve and the outer peripheral wall of the moving iron, thereby increasing the friction force of the moving iron when it moves relative to the magnetic sleeve in the magnetic sleeve, making the hysteresis of the proportional valve worse.

[0042] In order to solve the above problems, Figure 1 and Figure 2 As shown, this embodiment provides a proportional valve, which includes a magnetic sleeve 1, a movable iron 2, and a lubricating member 3, wherein the movable iron 2 is movably arranged in the magnetic sleeve 1, the lubricating member 3 is located in the radial gap between the magnetic sleeve 1 and the movable iron 2, and the movable iron 2 can move axially along the magnetic sleeve 1 relative to the lubricating member 3. The proportional valve provided in this embodiment, by arranging the lubricating member 3 in the radial gap between the magnetic sleeve 1 and the movable iron 2, allows the movable iron 2 to move axially along the magnetic sleeve 1 relative to the lubricating member 3, thereby greatly reducing the relative friction between the movable iron 2 and the lubricating member 3, so that the proportional valve has the advantages of small hysteresis and high precision, and the lubricating member 3 can maintain low friction performance for a long time, avoiding the deterioration of the hysteresis of the proportional valve. In addition, by arranging the lubricating member 3 to reduce the friction resistance of the movable iron 2 during movement, the processing accuracy requirements for the movable iron 2 and the magnetic sleeve 1 are reduced, the processing cost is reduced, and the processing efficiency is improved.

[0043] Optionally, in this embodiment, the lubricating component 3 includes a base material and a coating layer applied to the outer surface of the base material, wherein the base material is made of a glass fiber material and the coating layer is a polytetrafluoroethylene material. By coating the coating layer of polytetrafluoroethylene material on the surface of the base material, the lubricity of the outer surface of the lubricating component 3 is effectively improved. In addition, by designing the base material to be a glass fiber material, the cost is reduced, the structural strength of the lubricating component 3 is ensured, and the lubricating component 3 has a certain flexibility, which facilitates the production and installation of the lubricating component 3. Specifically, a thin sheet-like base material can be produced first, and then the base material can be cut and coated on the outer surface of the base material. The base material coated with the coating layer is then wound in the radial gap between the magnetic sleeve 1 and the moving iron 2.

[0044] In this embodiment, if Figure 1 and Figure 2As shown, the interior of the magnetic sleeve 1 is provided with a mounting cavity 11, and the proportional valve further includes a first position-limiting member 4, which is fixed in the inner cavity wall of the mounting cavity 11. The movable iron 2 is movably arranged in the mounting cavity 11 and can pass through the first position-limiting member 4. The two ends of the lubricating member 3 along the axial direction of the magnetic sleeve 1 are respectively a first end 31 and a second end 32, the first end 31 abuts against the bottom wall of the mounting cavity 11, and the second end 32 abuts against the first position-limiting member 4. The above arrangement enables the bottom wall of the mounting cavity 11 and the first position-limiting member 4 to limit the lubricating member 3 in the axial direction, thereby preventing the lubricating member 3 from following the movable iron 2 relative to the magnetic sleeve 1 along the axial direction of the magnetic sleeve 1, thereby ensuring the stability and reliability of the relative position of the lubricating member 3 and the magnetic sleeve 1.

[0045] In this embodiment, if Figure 1 and Figure 3 As shown, a mounting groove 111 is defined on the inner wall of the mounting cavity 11. The first position-limiting member 4 includes an elastic circlip 41 and a limiting ring 42. The elastic circlip 41 is fixed in the mounting groove 111, and the limiting ring 42 is sandwiched between the elastic circlip 41 and the second end 32. This arrangement causes the elastic circlip 41 to press against the limiting ring 42, causing the limiting ring 42 to abut against the second end 32, thereby achieving elastic abutment and limiting of the lubricating member 3, avoiding rigid abutment and limiting of the lubricating member 3, and improving protection of the lubricating member 3.

[0046] In this embodiment, if Figure 1 and Figure 3As shown, the proportional valve also includes a coil 5, a valve sleeve 6, a main valve core 7, a pilot valve core 8 and an elastic member 9, wherein the coil 5 is fixedly sleeved on the outer periphery of the magnetic sleeve 1, the valve sleeve 6 is fixedly connected to the end of the magnetic sleeve 1, and a first port 61 and a second port 62 are provided on the valve sleeve 6. The main valve core 7 is slidably arranged in the valve sleeve 6. The main valve core 7 can connect the first port 61 and the second port 62 or block the first port 61 and the second port 62. One end of the pilot valve core 8 is connected to the end of the moving iron 2, and the other end of the pilot valve core 8 can abut against the main valve core 7, and the pilot valve core 8 can drive the main valve core 7 to slide to a position that blocks the first port 61 and the second port 62. The elastic member 9 is located between the magnetic sleeve 1 and the moving iron 2. The elastic member 9 always has a tendency to drive the moving iron 2 to move toward the pilot valve core 8 and enable the pilot valve core 8 to drive the main valve core 7 to move. When the coil 5 does not generate a magnetic field, no electromagnetic force is generated. Under the action of the elastic part 9, the moving iron 2 moves toward the pilot valve core 8 and drives the pilot valve core 8 to drive the main valve core 7 to move to the position of isolating the first port 61 and the second port 62; when the magnetic induction intensity of the magnetic field generated by the coil 5 becomes larger and larger, a certain electromagnetic force is generated, causing the moving iron 2 to pull the pilot valve core 8 to slide in the direction away from the main valve core 7. At this time, the elastic part 9 is compressed until the electromagnetic force is balanced with the elastic force of the elastic part 9, and when the moving iron 2 pulls the pilot valve core 8 to slide in the direction away from the main valve core 7, the main valve core 7 is no longer subject to the pressure driving force of the pilot valve core 8. Under the action of the hydraulic oil, the main valve core 7 can slide with the pilot valve core 8, so that the main valve core 7 moves to the position of connecting the first port 61 and the second port 62, so that the hydraulic oil can output a corresponding flow from the second port 62 to the first port 61, thereby adjusting the speed of the actuator.

[0047] Optionally, in this embodiment, if Figure 1 As shown, the elastic member 9 is a spring. Optionally, a connecting member 13 is connected to the bottom wall of the installation cavity 11, and a contact groove 22 is formed on the side of the movable iron 2 facing the connecting member 13. One end of the elastic member 9 is sleeved on the connecting member 13, and the other end of the elastic member 9 is located in the contact groove 22.

[0048] It should be noted that if Figure 1 As shown, the proportional valve further includes a locking nut 20. The locking nut 20 is screwed onto the end of the magnetic sleeve 1 that extends outside the coil 5. The locking nut 20 abuts against one end of the coil 5, and the other end of the coil 5 abuts against the limiting shoulder of the magnetic sleeve 1, thereby ensuring the stability of the coil 5 mounted on the magnetic sleeve 1. In addition, in this embodiment, the other end of the magnetic sleeve 1 that extends outside the coil 5 (i.e., the end where the magnetic sleeve 1 is connected to the valve sleeve 6) is provided with an external thread. The other end of the magnetic sleeve 1 that extends outside the coil 5 can be connected to the relevant valve group structure via the external thread.

[0049] Optionally, in this embodiment, if Figure 1As shown, the magnetic sleeve 1 is provided with a magnetic isolation copper 12. By providing the magnetic isolation copper 12 on the magnetic sleeve 1, the magnetic sleeve 1 can reasonably distribute the magnetic induction intensity in the axial and radial directions of the magnetic sleeve 1, ensuring that the electromagnetic force generated within the working stroke does not change with the position of the moving iron 2.

[0050] In this embodiment, if Figure 1 and Figure 3 As shown, the outer wall of the main valve core 7 is provided with an oil inlet groove 71 connected to the second port 62. When the moving iron 2 drives the pilot valve core 8 to move in the direction away from the pilot valve core 8, the hydraulic oil entering the oil inlet groove 71 through the second port 62 can drive the main valve core 7 to slide toward the position of the first port 61 and the second port 62.

[0051] In this embodiment, if Figure 1 and Figure 3 As shown, the proportional valve also includes a second limit member 10, which is fixed in the inner cavity wall of the installation cavity 11. The second limit member 10 can abut against the main valve core 7 to limit the extreme position of the main valve core 7 sliding toward the position of the first and second ports 61 and 62. The extreme position of the sliding of the main valve core 7 is limited by the second limit member 10, which can meet the design flow of the proportional valve. Specifically, the second limit member 10 can be in the form of a limit ring. Optionally, in this embodiment, the two ends of the limit ring are respectively abutted by the step wall of the installation cavity 11 and the end of the valve sleeve 6, thereby realizing the positioning of the limit ring in the installation cavity 11.

[0052] In this embodiment, if Figure 1 and Figure 3 As shown, a connecting cavity 21 is provided in the movable iron 2, which extends through the movable iron 2 in the axial direction. The connecting cavity 21 is connected to the mounting cavity 11. An oil inlet cavity 30 is formed between the pilot valve core 8 and the main valve core 7. The oil inlet cavity 30 is connected to the connecting cavity 21, and the oil inlet cavity 30 is connected to the second port 62. The above arrangement enables the mounting cavity 11, the connecting cavity 21, and the oil inlet cavity 30 to be connected to each other, and the hydraulic oil can flow into the mounting cavity 11, the connecting cavity 21, and the oil inlet cavity 30 through the second port 62. In addition, the above arrangement enables the connecting cavity 21 to connect the mounting cavity 11 and the oil inlet cavity 30 on both sides of the axial direction, thereby ensuring the reliability of the movement of the movable iron 2. In this embodiment, the connecting cavity 21 is connected to the abutment groove 22.

[0053] In this embodiment, if Figure 3 and Figure 4As shown, the outer peripheral wall of the main valve core 7 is provided with a radial oil inlet hole 72, which connects the second port 62 and the oil inlet chamber 30. The end of the main valve core 7 is provided with an axial oil inlet hole 73, which can connect the first port 61 and the oil inlet chamber 30. When the other end of the pilot valve core 8 abuts against the main valve core 7, the other end of the pilot valve core 8 blocks the axial oil inlet hole 73. When the coil 5 does not generate a magnetic field, the other end of the pilot valve core 8 blocks the axial oil inlet hole 73. At this time, only the hydraulic oil at the first port 61 enters the oil inlet chamber 30 through the radial oil inlet hole 72, ensuring the sealing effect between the first port 61 and the second port 62. It should be noted that in this embodiment, the bottom wall of the oil inlet groove 71 is provided with a radial oil inlet hole 72.

[0054] In this embodiment, if Figure 3 and Figure 5 As shown, the pilot valve core 8 includes a T-shaped connecting portion 81, a main body 82, and an abutting portion 83, which are sequentially connected along its axial direction. The side of the movable iron 2 facing the pilot valve core 8 is provided with a T-shaped connecting groove 23 that is connected to the communication chamber 21. The T-shaped connecting portion 81 is connected to the T-shaped connecting groove 23, and the abutting portion 83 can abut the end surface of the main valve core 7. Optionally, in this embodiment, the T-shaped connecting portion 81 and the T-shaped connecting groove 23 are clearance-matched. The outer diameter of the main body 82 is larger than the outer diameters of the T-shaped connecting portion 81 and the abutting portion 83. In addition, a connecting groove 821 extending along its axial direction is formed on the outer peripheral wall of the main body 82, thereby creating a radial gap between the main body 82 and the main valve core 7. Moreover, due to the clearance fit between the T-shaped connecting portion 81 and the T-shaped connecting groove 23, a gap is formed between the T-shaped connecting portion 81 and the T-shaped connecting groove 23, thereby ensuring the communication between the communication chamber 21 and the oil inlet chamber 30.

[0055] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A proportional valve, characterized in that: include: Magnetic conductive sleeve (1); A moving iron (2), the moving iron (2) being movably arranged in the magnetic conductive sleeve (1); as well as A lubricating member (3) is located in a radial gap between the magnetic sleeve (1) and the movable iron (2), and the movable iron (2) can move relative to the lubricating member (3) along the axial direction of the magnetic sleeve (1).

2. The proportional valve according to claim 1, characterized in that: The lubricating component (3) comprises a base material and a coating layer coated on the outer surface of the base material, the base material is made of glass fiber material, and the coating layer is made of polytetrafluoroethylene material.

3. The proportional valve according to claim 1 or 2, characterized in that: The magnetic conductive sleeve (1) is provided with an installation cavity (11) inside, and the proportional valve further includes a first limiting member (4), the first limiting member (4) is fixed in the inner cavity wall of the installation cavity (11), the movable iron (2) is movably arranged in the installation cavity (11), and the movable iron (2) can pass through the first limiting member (4); Both ends of the lubricating member (3) along the axial direction of the magnetic sleeve (1) are respectively in contact with the bottom wall of the mounting cavity (11) and the first limiting member (4).

4. The proportional valve according to claim 3, characterized in that: An installation groove (111) is provided on the inner wall of the installation cavity (11), and the first limiting member (4) comprises: an elastic retaining ring (41), the elastic retaining ring (41) being fixed in the mounting groove (111); and A limiting ring (42) is sandwiched between the elastic retaining ring (41) and the lubricating member (3).

5. The proportional valve according to claim 3, characterized in that: The proportional valve further comprises: A coil (5), wherein the coil (5) is fixedly sleeved on the outer periphery of the magnetic conductive sleeve (1); a valve sleeve (6), the valve sleeve (6) being fixedly connected to the end of the magnetic conductive sleeve (1), and the valve sleeve (6) being provided with a first port (61) and a second port (62); a main valve core (7), the main valve core (7) being slidably disposed in the valve sleeve (6), the main valve core (7) being capable of connecting the first port (61) and the second port (62) or blocking the first port (61) and the second port (62); a pilot valve core (8), one end of the pilot valve core (8) being connected to the end of the movable iron (2), the other end of the pilot valve core (8) being capable of abutting against the main valve core (7), and the pilot valve core (8) being capable of driving the main valve core (7) to slide to a position that blocks the first port (61) and the second port (62); and An elastic member (9), the elastic member (9) is located between the magnetic sleeve (1) and the movable iron (2), and the elastic member (9) is configured to always have a tendency to drive the movable iron (2) toward the pilot valve core (8) and enable the pilot valve core (8) to drive the main valve core (7) to move.

6. The proportional valve according to claim 5, characterized in that: An oil inlet groove (71) communicating with the second port (62) is provided on the outer peripheral wall of the main valve core (7). When the movable iron (2) drives the pilot valve core (8) to move in a direction away from the pilot valve core (8), the hydraulic oil entering the oil inlet groove (71) through the second port (62) can drive the main valve core (7) to slide toward a position connecting the first port (61) and the second port (62).

7. The proportional valve according to claim 6, characterized in that: The proportional valve further comprises: A second limiting member (10) is fixed in the inner wall of the mounting cavity (11), and the second limiting member (10) can abut against the main valve core (7) to limit the main valve core (7) from sliding to an extreme position of the position that guides the first port (61) and the second port (62).

8. The proportional valve according to claim 5, characterized in that: The movable iron (2) is provided with a connecting cavity (21) extending through the movable iron (2) along its axial direction, the connecting cavity (21) is connected to the mounting cavity (11), an oil inlet cavity (30) is formed between the pilot valve core (8) and the main valve core (7), the oil inlet cavity (30) is connected to the connecting cavity (21), and the oil inlet cavity (30) is connected to the second port (62).

9. The proportional valve according to claim 8, characterized in that: The outer peripheral wall of the main valve core (7) is provided with a radial oil inlet hole (72), and the radial oil inlet hole (72) is connected to the second port (62) and the oil inlet chamber (30); the end of the main valve core (7) is provided with an axial oil inlet hole (73), and the axial oil inlet hole (73) can be connected to the first port (61) and the oil inlet chamber (30). When the other end of the pilot valve core (8) abuts against the main valve core (7), the other end of the pilot valve core (8) blocks the axial oil inlet hole (73).

10. The proportional valve according to claim 1 or 2, characterized in that: Magnetic isolation copper (12) is provided on the magnetic conductive sleeve (1).

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