Proportional electromagnetic valve

Abstract

The utility model provides a proportional electromagnetic valve, and belongs to the technical field of electromagnetic valves. The problem that an existing proportional electromagnetic valve is poor in stability is solved. The proportional electromagnetic valve comprises a valve sleeve provided with an oil inlet and an oil outlet and a main valve element movably arranged in the valve sleeve, the valve sleeve is internally provided with a sealing part and a throttling part which are annularly and inwards protruded and are arranged at intervals, and the sealing part and the throttling part are both located between the oil inlet and the oil outlet. The main valve element is provided with a conical sealing face and a conical throttling face which are arranged at intervals, the small-diameter end of the sealing face and the small-diameter end of the throttling face both face the oil outlet, when the sealing face abuts against the sealing portion, the throttling face is located in the throttling portion, the outer circumferential wall of the main valve element is attached to the inner circumferential wall of the throttling portion, and when the sealing face is away from the sealing portion by a certain distance, the throttling face is located in the throttling portion. And a gap for oil liquid to flow is formed between the throttling surface and the throttling part. The proportional electromagnetic valve has the advantages that the opening and closing process of the main valve element is smooth and does not shake, and the stability of the proportional electromagnetic valve is improved.

Description

Technical Field

[0001] This utility model belongs to the field of electromagnetic valve technology and relates to a proportional electromagnetic valve. Background Technology

[0002] The hydraulic system of existing construction machinery includes a gravity lowering mechanism, a proportional solenoid valve, and a pressure compensation valve. The proportional solenoid valve and the pressure compensation valve form a flow valve to control the descent speed of gravity lowering, so that the descent speed is only related to the magnitude of the solenoid valve current and is independent of the load of the gravity lowering mechanism, thereby effectively improving the operation performance of descent.

[0003] Existing proportional solenoid valves, such as the electromagnetic proportional valve, flow valve, and hydraulic system disclosed in Chinese patent literature [Patent No.: 202110260851.X; Authorization Announcement No.: CN112901584B], have a proportional coil installed on a sleeve, an armature slidably disposed within the proportional coil, and a spring disposed between the armature and the sleeve; a first port and a second port are provided on the valve seat; a main valve core is used to switch the connection between the first port and the second port; one end of a pilot valve core passes through the armature, and the other end slides through the main valve core and can abut against the valve port of the main valve core; a first pilot control chamber is formed between the pilot valve core, the main valve core, and the valve seat; a second pilot control chamber is formed between the pilot valve core and the main valve core; the first port is connected to the first pilot control chamber; the first pilot control chamber is connected to the second port through a connecting oil passage; the force of the hydraulic oil in the first pilot control chamber on the pilot valve core is the same as the force of the hydraulic oil in the second pilot control chamber on the pilot valve core.

[0004] In this type of electromagnetic proportional valve, a main valve core is slidably mounted within the valve seat. The main valve core is configured to selectively abut against the valve seat at a position between the first and second ports to control the on / off connection between the first and second ports. However, in this type of electromagnetic proportional valve, the right end of the main valve core has a sealing surface, and the valve seat has an inwardly protruding, annular sealing portion that abuts against the sealing surface to form a seal. When the main valve core moves to the left, causing the sealing surface to leave the sealing portion, the oil in the first port will rapidly flow to the second port. This large change in oil flow rate and impact force causes the main valve core to vibrate, reducing the stability of the electromagnetic proportional valve. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a proportional solenoid valve. The technical problem solved is how to make the opening and closing process of the main valve core smooth and without vibration, thereby improving the stability of the proportional solenoid valve.

[0006] The objective of this utility model can be achieved through the following technical solution: A proportional solenoid valve includes a valve sleeve having an oil inlet and an oil outlet, and a main valve core movably disposed in the valve sleeve. The valve sleeve has a sealing portion and a throttling portion, both annularly protruding inwards and spaced apart, located between the oil inlet and the oil outlet. The main valve core has a sealing surface and a throttling surface, both conical and spaced apart, with the smaller diameter ends of the sealing surface and the throttling surface facing the oil outlet. When the sealing surface abuts against the sealing portion, the throttling surface is located within the throttling portion, and the outer peripheral wall of the main valve core is in contact with the inner peripheral wall of the throttling portion. When the sealing surface moves a certain distance away from the sealing portion, a gap for oil flow is formed between the throttling surface and the throttling portion.

[0007] When the proportional solenoid valve is closed, the sealing surface abuts against the sealing part to form a seal. When the proportional solenoid valve is opened, the main valve core moves, causing the sealing surface to no longer abut against the sealing part. After the sealing surface moves a certain distance away from the sealing part, a gap for oil flow is formed between the throttling surface and the throttling part due to the conical shape of the throttling surface and the smaller diameter end of the throttling surface facing the oil outlet. This gap is small, meaning the flow cross-sectional area is small, allowing a small amount of oil to flow from the oil inlet to the oil outlet. As the main valve core moves, this gap gradually increases until the throttling surface moves away from the throttling part, gradually increasing the amount of oil flowing from the oil inlet to the oil outlet. This results in a smaller change in the oil flow rate from the oil inlet to the oil outlet when the proportional solenoid valve is first opened, reducing the impact force of the oil on the main valve core, making the opening process of the main valve core smooth and vibration-free, and improving the stability of the proportional solenoid valve. Similarly, when the proportional solenoid valve is closed, the cross-sectional area of ​​the flow between the throttling surface and the throttling section gradually decreases, thus gradually reducing the amount of oil flowing from the inlet to the outlet. This results in a smaller change in the oil flow rate from the inlet to the outlet, reducing the impact force of the oil on the main valve core, making the closing process of the main valve core smooth and vibration-free, and improving the stability of the proportional solenoid valve. In this proportional solenoid valve, the sealing surface and throttling surface are set separately, reducing machining difficulty, improving machining accuracy, and enhancing the sealing effect of the sealing surface.

[0008] In the aforementioned proportional solenoid valve, the throttling section has a first guide surface arranged along the axial direction of the valve sleeve, and the main valve core has a second guide surface arranged along the axial direction of the valve sleeve. The second guide surface is located between the sealing surface and the throttling surface, and is connected to the throttling surface. When the sealing surface abuts against the sealing section, the first guide surface and the second guide surface are in contact. When the sealing surface abuts against the sealing section, the first guide surface and the second guide surface are in contact. When the main valve core moves to make the sealing surface leave the sealing section, and the movement distance is within a certain distance, the first guide surface and the second guide surface are still in contact, and the main valve core is still in contact with the throttling section. This reduces the impact of the oil on the main valve core and allows the oil to approach the throttling section and the throttling surface. After the sealing surface leaves the sealing section by a certain distance, the oil can pass through the gap between the throttling surface and the throttling section more smoothly, reducing the impact force of the oil on the main valve core. This makes the opening process of the main valve core smooth and vibration-free, improving the stability of the proportional solenoid valve.

[0009] In the aforementioned proportional solenoid valve, a first annular receiving groove is provided between the sealing part and the throttling part, and a second annular receiving groove is provided on the main valve core. The second receiving groove is located between the sealing surface and the second guide surface, and the first receiving groove and the second receiving groove are connected. Oil passing through the sealing surface can first enter the first and second receiving grooves, allowing the oil to pass more smoothly through the gap between the throttling surface and the throttling part, reducing the impact force of the oil on the main valve core, making the opening process of the main valve core smooth and vibration-free, and improving the stability of the proportional solenoid valve.

[0010] In the aforementioned proportional solenoid valve, the sidewall of the sealing part facing the throttling part is a conical first guide wall, with the larger diameter end of the first guide wall facing the oil outlet. The wall of the second receiving groove near the second guide surface is a conical second guide wall, with the smaller diameter end of the second guide wall facing the oil outlet. When the sealing part moves axially along the valve sleeve to the middle of the second receiving groove, the second guide surface moves to the middle of the first receiving groove, causing the first and second guide walls to be positioned opposite each other. This allows the sealing part, the second receiving groove, the throttling part, and the first receiving groove to cooperate in forming an S-shaped flow channel for oil flow between the oil inlet and the oil outlet. This structure allows the oil to flow in the S-shaped curved flow channel, gradually changing the oil's speed and direction. This reduces local pressure fluctuations and eddy current formation, lowers the impact of the oil on the main valve core, and ensures smooth, vibration-free opening and closing of the main valve core, thus improving the stability of the proportional solenoid valve.

[0011] In the aforementioned proportional solenoid valve, the angle between the sealing surface and the central axis of the valve sleeve is greater than the angle between the throttling surface and the central axis of the valve sleeve. This structure ensures the sealing effect of the sealing surface and reduces the cross-sectional area of ​​the gap between the throttling surface and the throttling section, allowing the oil flow rate to change gradually, improving the stability of the main valve core, and thus enhancing the stability of the proportional solenoid valve.

[0012] In the aforementioned proportional solenoid valve, the angle between the sealing surface and the central axis of the valve sleeve is between 40-50°, and the angle between the throttling surface and the central axis of the valve sleeve is between 10-20°.

[0013] In the aforementioned proportional solenoid valve, the proportional solenoid valve further includes a magnetic sleeve fixedly connected to the valve sleeve, a moving iron core passing through the magnetic sleeve, a pilot valve core, and a spring. A coil is disposed outside the magnetic sleeve. The main valve core has a connecting channel, a first oil passage, and a second oil passage. The pilot valve core has a third oil passage. One end of the pilot valve core is connected to the moving iron core, and the other end passes through the connecting channel. A first oil cavity is provided between the main valve core and the moving iron core. The oil inlet is connected to the first oil cavity through the first oil passage. The first oil cavity is connected to the oil outlet through the outer end of the connecting channel and the second oil passage. The first oil cavity is connected to the inner end of the connecting channel through the third oil passage. The two ends of the spring act on the magnetic sleeve and the pilot valve core, or the two ends of the spring act on the magnetic sleeve and the moving iron core, respectively. When the coil is energized, it overcomes the spring force and drives the moving iron core to move. The magnitude of the coil current controls the opening degree of the proportional solenoid valve. Oil enters the inner end of the connecting channel from the inlet through the first oil passage, the first oil chamber, and the third oil passage, making the oil pressure at both ends of the pilot valve core the same, avoiding pilot valve core vibration, and thus improving the stability of the proportional solenoid valve. The movement of the moving iron core can pull the pilot valve core to move, so that oil flows from the inlet through the first oil passage, the first oil chamber, the outer end of the connecting channel, and the second oil passage to the outlet. At this time, the pressure in the first oil chamber will be lower than the pressure at the inlet, but it will not drop very quickly. The pressure at the inlet pushes the main valve core to move to the left (open) or to the right (close) linearly, without violent and rapid movement, ensuring that the flow rate during opening and closing is continuous and linear, making the opening and closing process of the main valve core smooth and vibration-free, thus improving the stability of the proportional solenoid valve. The two ends of the spring act on the magnetic sleeve and the pilot valve core respectively, which can adjust the maximum stroke of the moving iron core, that is, adjust the maximum opening flow of the proportional solenoid valve; the two ends of the spring act on the magnetic sleeve and the moving iron core respectively, which can adjust the spring preload, that is, adjust the starting current of the proportional solenoid valve.

[0014] In the aforementioned proportional solenoid valve, the third oil passage includes a main oil passage arranged axially along the pilot valve core and a branch oil passage arranged radially along the pilot valve core. The outer peripheral wall of the pilot valve core away from the inner end of the moving iron core has a connecting groove. The groove depth is 1 / 15 to 1 / 25 of the diameter of the pilot valve core. The main oil passage is connected to the inner end of the connecting channel through the branch oil passage and the connecting groove.

[0015] In the aforementioned proportional solenoid valve, the pilot valve core has a conical abutment surface and an annular transition groove. When the abutment surface abuts against the main valve core, it can disconnect the first oil chamber from the second oil passage. When the abutment surface leaves the main valve core, it allows the first oil chamber to connect with the second oil passage through the transition groove.

[0016] In the aforementioned proportional solenoid valve, the valve sleeve has a first oil hole, and the main valve core has a second oil hole that communicates with the first oil passage. The first oil hole and the second oil hole can communicate with each other. The first oil hole and the second oil hole regulate the oil pressure in the first oil chamber, ensuring smooth movement of the pilot valve core and the main valve core, thereby improving the stability of the proportional solenoid valve.

[0017] Compared with the prior art, the proportional solenoid valve provided by this utility model has the following advantages:

[0018] 1. The throttling surface and sealing surface of this proportional solenoid valve are spaced apart, so that when the main valve core is opened, a gap for oil flow is formed between the throttling surface and the throttling part. This gap is small, allowing a small amount of oil to flow from the inlet to the outlet. As the main valve core moves, the gap gradually increases until the throttling surface leaves the throttling part, gradually increasing the amount of oil flowing from the inlet to the outlet. This reduces the change in oil flow rate from the inlet to the outlet, reduces the impact force of the oil on the main valve core, and makes the opening process of the main valve core smooth and vibration-free, improving the stability of the proportional solenoid valve. The same principle applies when the main valve core is closed.

[0019] 2. This proportional solenoid valve, by setting a throttling section and throttling surface, forms an S-shaped flow channel for oil flow between the oil inlet and outlet when fully opened. This gradually changes the speed and direction of the oil, reducing local pressure fluctuations and eddy current formation, reducing the impact of the oil on the main valve core, and making the opening and closing process of the main valve core smooth and vibration-free, thus improving the stability of the proportional solenoid valve. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the proportional solenoid valve when it is closed.

[0021] Figure 2 This is a cross-sectional view of the proportional solenoid valve when it is slightly open.

[0022] Figure 3 This is a cross-sectional view of the proportional solenoid valve when it is fully open.

[0023] Figure 4 This is a cross-sectional view of the inner end of the pilot valve core of this proportional solenoid valve.

[0024] Figure 5 This is a cross-sectional view of the overall structure of Embodiment 2 of the proportional solenoid valve.

[0025] In the diagram, 1. Valve sleeve; 11. Oil inlet; 12. Oil outlet; 13. Sealing part; 131. First guide wall; 14. Throttling part; 141. First guide surface; 15. First receiving groove; 16. First oil hole; 2. Main valve core; 21. Sealing surface; 22. Throttling surface; 23. Second guide surface; 24. Second receiving groove; 241. Second guide wall; 25. Connecting channel; 26. First oil passage; 27. Second oil passage; 28. Second oil hole; 3. Magnetic sleeve; 4. Moving iron core; 5. Pilot valve core; 51. Third oil passage; 511. Main oil passage; 512. Branch oil passage; 513. Connecting groove; 52. Abutment surface; 53. Transition groove; 6. Spring; 7. Coil; 8. First oil chamber. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] Example 1

[0028] like Figure 1 , Figure 2 , Figure 3 As shown, this proportional solenoid valve includes a valve sleeve 1, a main valve core 2, a magnetic sleeve 3, a moving iron core 4, a pilot valve core 5, a spring 6, and a coil 7.

[0029] The valve sleeve 1 has an oil inlet 11 around its circumference and an oil outlet 12 at its end. The valve sleeve 1 is fixedly connected to the magnetic sleeve 3. The main valve core 2 is movably disposed in the valve sleeve 1. The moving iron core 4, the pilot valve core 5, and the spring 6 pass through the magnetic sleeve 3, and the coil 7 is sleeved outside the magnetic sleeve 3. The main valve core 2 has a connecting channel 25, a first oil passage 26, and a second oil passage 27. The pilot valve core 5 has a third oil passage 51. One end of the pilot valve core 5 is connected to the moving iron core 4, and the other end passes through the connecting channel 25. The spring 6 is sleeved outside the pilot valve core 5, and the two ends of the spring 6 act on the magnetic sleeve 3 and the pilot valve core 5, respectively.

[0030] like Figure 4As shown, the third oil passage 51 includes a main oil passage 511 arranged axially along the pilot valve core 5 and a branch oil passage 512 arranged radially along the pilot valve core 5. The outer peripheral wall of the inner end of the pilot valve core 5 away from the moving iron core 4 has a connecting groove 513. The main oil passage 511 is connected to the inner end of the connecting channel 25 through the branch oil passage 512 and the connecting groove 513. In this embodiment, the depth of the connecting groove 513 is 1 / 20 of the diameter of the pilot valve core 5. In actual production, the depth of the connecting groove 513 can be 1 / 15 or 1 / 25 of the diameter of the pilot valve core 5. The pilot valve core 5 has a conical abutment surface 52 and an annular transition groove 53. The abutment surface 52 can abut against the main valve core 2.

[0031] A first oil chamber 8 is located between the main valve core 2 and the moving iron core 4. The oil inlet 11 is connected to the first oil chamber 8 through the first oil passage 26. The first oil chamber 8 is connected to the oil outlet 12 through the outer end of the connecting channel 25, the transition groove 53, and the second oil passage 27. The first oil chamber 8 is connected to the inner end of the connecting channel 25 through the main oil passage 511, the branch oil passage 512, and the connecting groove 513. When the abutting surface 52 abuts against the main valve core 2, it can isolate the connection between the first oil chamber 8 and the second oil passage 27. When the abutting surface 52 leaves the main valve core 2, it can allow the first oil chamber 8 to connect with the second oil passage 27 through the transition groove 53.

[0032] The valve sleeve 1 has a first oil hole 16, and the main valve core 2 has a second oil hole 28 that is connected to the first oil passage 26. When the proportional solenoid valve is at a certain opening, the first oil hole 16 and the second oil hole 28 are connected.

[0033] The valve sleeve 1 has a sealing part 13 and a throttling part 14 that are both annularly protruding and spaced apart. The sealing part 13 and the throttling part 14 are both located between the oil inlet 11 and the oil outlet 12. There is an annular first receiving groove 15 between the sealing part 13 and the throttling part 14. The throttling part 14 has a first guide surface 141 that is arranged along the axial direction of the valve sleeve 1.

[0034] The main valve core 2 has a sealing surface 21 and a throttling surface 22, both conical and spaced apart. The smaller diameter ends of the sealing surface 21 and the throttling surface 22 face the oil outlet 12. The angle between the sealing surface 21 and the central axis of the valve sleeve 1 is greater than the angle between the throttling surface 22 and the central axis of the valve sleeve 1. In this embodiment, the angle between the sealing surface 21 and the central axis of the valve sleeve 1 is 45°, and the angle between the throttling surface 22 and the central axis of the valve sleeve 1 is 15°. In actual production, the angle between the sealing surface 21 and the central axis of the valve sleeve 1 can be 40° or 50°, and the angle between the throttling surface 22 and the central axis of the valve sleeve 1 can be 10° or 20°.

[0035] The main valve core 2 has a second guide surface 23 arranged along the axial direction of the valve sleeve 1. The second guide surface 23 is located between the sealing surface 21 and the throttling surface 22, and the second guide surface 23 is connected to the throttling surface 22. The main valve core 2 has an annular second receiving groove 24, which is located between the sealing surface 21 and the second guide surface 23. The first receiving groove 15 is connected to the second receiving groove 24.

[0036] The side wall of the sealing part 13 facing the throttling part 14 is a conical first guide wall 131, with the larger diameter end of the first guide wall 131 facing the oil outlet 12. The wall of the second receiving groove 24 near the second guide surface 23 is a conical second guide wall 241, with the smaller diameter end of the second guide wall 241 facing the oil outlet 12. When the sealing part 13 moves relative to the middle of the second receiving groove 24 along the axial direction of the valve sleeve 1, the second guide surface 23 moves to the middle of the first receiving groove 15, so that the first guide wall 131 and the second guide wall 241 are arranged opposite to each other, so that the sealing part 13, the second receiving groove 24, the throttling part 14 and the first receiving groove 15 cooperate to form an S-shaped flow channel for oil supply between the oil inlet 11 and the oil outlet 12.

[0037] like Figure 1 As shown, when the proportional solenoid valve is closed, the sealing surface 21 abuts against the sealing part 13 to form a seal, the throttling surface 22 is located in the throttling part 14, and the first guide surface 141 is in contact with the second guide surface 23. When the proportional solenoid valve is opened, as shown... Figure 2 As shown, when the sealing surface 21 is less than a certain distance away from the sealing part 13 (set to 3mm), i.e., when the valve core moves 0-3mm to the left, the throttling surface 22 is located in the throttling part 14, and the first guide surface 141 and the second guide surface 23 remain in contact. Oil enters the first receiving groove 15 and the second receiving groove 24 through the sealing surface 21, but does not flow to the oil outlet 12. When the sealing surface 21 is a certain distance away from the sealing part 13, i.e., when the valve core moves more than 3mm to the left, a gap for oil flow is formed between the throttling surface 22 and the throttling part 14. The oil in the first receiving groove 15 and the second receiving groove 24 flows to the oil outlet 12 through this gap. As the valve core continues to move to the left, the cross-sectional area of ​​the gap increases until the throttling surface 22 completely leaves the throttling part 14. Figure 3 As shown, the proportional solenoid valve is at its maximum opening at this time. The sealing part 13, the second receiving groove 24, the throttling part 14, and the first receiving groove 15 cooperate to form an S-shaped flow channel. When the proportional solenoid valve is closed, the main valve core 2 moves to the right, and the throttling surface 22 first enters the throttling part 14. Then, the first guide surface 141 and the second guide surface 23 come into contact until the sealing surface 21 abuts against the sealing part 13.

[0038] Example 2

[0039] like Figure 5As shown, the structure and principle of this embodiment are basically the same as those of Embodiment 1. The difference is that in this embodiment, the two ends of the spring 6 act on the magnetic sleeve 3 and the moving iron core 4 respectively.

[0040] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

[0041] Although this document frequently uses terms such as valve sleeve 1, oil inlet 11, oil outlet 12, sealing part 13, first guide wall 131, throttling part 14, first guide surface 141, first receiving groove 15, first oil hole 16, main valve core 2, sealing surface 21, throttling surface 22, second guide surface 23, second receiving groove 24, second guide wall 241, connecting channel 25, first oil passage 26, second oil passage 27, second oil hole 28, magnetic sleeve 3, moving iron core 4, pilot valve core 5, third oil passage 51, main oil passage 511, branch oil passage 512, connecting groove 513, abutting surface 52, transition groove 53, spring 6, coil 7, and first oil chamber 8, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.

Claims

1. A proportional solenoid valve, comprising a valve sleeve (1) having an oil inlet (11) and an oil outlet (12) and a main valve core (2) movably disposed within the valve sleeve (1), characterized in that, The valve sleeve (1) has a sealing part (13) and a throttling part (14) that are both annularly protruding and spaced apart. The sealing part (13) and the throttling part (14) are both located between the oil inlet (11) and the oil outlet (12). The main valve core (2) has a sealing surface (21) and a throttling surface (22) that are both conical and spaced apart. The smaller diameter ends of the sealing surface (21) and the throttling surface (22) face the oil outlet (12). When the sealing surface (21) abuts against the sealing part (13), the throttling surface (22) is located in the throttling part (14) and the outer peripheral wall of the main valve core (2) is in contact with the inner peripheral wall of the throttling part (14). When the sealing surface (21) moves away from the sealing part (13) by a certain distance, a gap for oil flow is formed between the throttling surface (22) and the throttling part (14).

2. A proportional solenoid valve according to claim 1, characterized in that, The throttling section (14) has a first guide surface (141) arranged along the axial direction of the valve sleeve (1), and the main valve core (2) has a second guide surface (23) arranged along the axial direction of the valve sleeve (1). The second guide surface (23) is located between the sealing surface (21) and the throttling surface (22), and the second guide surface (23) is connected to the throttling surface (22). When the sealing surface (21) abuts against the sealing section (13), the first guide surface (141) and the second guide surface (23) are in contact.

3. A proportional solenoid valve according to claim 2, characterized in that, There is an annular first receiving groove (15) between the sealing part (13) and the throttling part (14), and there is an annular second receiving groove (24) on the main valve core (2). The second receiving groove (24) is located between the sealing surface (21) and the second guide surface (23), and the first receiving groove (15) and the second receiving groove (24) are connected.

4. A proportional solenoid valve according to claim 3, characterized in that, The sealing part (13) has a tapered first guide wall (131) facing the throttling part (14), with the larger diameter end of the first guide wall (131) facing the oil outlet (12). The second receiving groove (24) has a tapered second guide wall (241) near the second guide surface (23), with the smaller diameter end of the second guide wall (241) facing the oil outlet (12). When the sealing part (13) is axially opposite to the valve sleeve (1), When the second guide surface (23) moves to the middle of the second receiving groove (24), the second guide surface (23) moves to the middle of the first receiving groove (15), so that the first guide wall (131) and the second guide wall (241) are arranged opposite to each other, so that the sealing part (13), the second receiving groove (24), the throttling part (14) and the first receiving groove (15) cooperate to form an S-shaped flow channel for oil supply between the oil inlet (11) and the oil outlet (12).

5. A proportional solenoid valve according to claim 1, 2, 3, or 4, characterized in that, The angle between the sealing surface (21) and the central axis of the valve sleeve (1) is greater than the angle between the throttling surface (22) and the central axis of the valve sleeve (1).

6. A proportional solenoid valve according to claim 5, characterized in that, The angle between the sealing surface (21) and the central axis of the valve sleeve (1) is between 40-50°, and the angle between the throttling surface (22) and the central axis of the valve sleeve (1) is between 10-20°.

7. A proportional solenoid valve according to claim 1, 2, 3, or 4, characterized in that, The proportional solenoid valve also includes a magnetic sleeve (3) fixedly connected to the valve sleeve (1), a moving iron core (4) passing through the magnetic sleeve (3), a pilot valve core (5), and a spring (6). A coil (7) is sleeved on the magnetic sleeve (3). The main valve core (2) has a connecting channel (25), a first oil passage (26), and a second oil passage (27). The pilot valve core (5) has a third oil passage (51). One end of the pilot valve core (5) is connected to the moving iron core (4), and the other end passes through the connecting channel (25). There is a connection between the main valve core (2) and the moving iron core (4). The first oil chamber (8) is connected to the first oil chamber (8) through the first oil passage (26). The first oil chamber (8) is connected to the oil outlet (12) through the outer end of the connecting channel (25) and the second oil passage (27). The first oil chamber (8) is connected to the inner end of the connecting channel (25) through the third oil passage (51). The two ends of the spring (6) act on the magnetic sleeve (3) and the pilot valve core (5) respectively, or the two ends of the spring (6) act on the magnetic sleeve (3) and the moving iron core (4) respectively.

8. A proportional solenoid valve according to claim 7, characterized in that, The third oil passage (51) includes a main oil passage (511) arranged axially along the pilot valve core (5) and a branch oil passage (512) arranged radially along the pilot valve core (5). The outer peripheral wall of the pilot valve core (5) away from the inner end of the moving iron core (4) has a connecting groove (513). The groove depth of the connecting groove (513) is 1 / 15-1 / 25 of the diameter of the pilot valve core (5). The main oil passage (511) is connected to the inner end of the connecting channel (25) through the branch oil passage (512) and the connecting groove (513).

9. A proportional solenoid valve according to claim 7, characterized in that, The pilot valve core (5) has a conical abutment surface (52) and an annular transition groove (53). When the abutment surface (52) abuts against the main valve core (2), it can disconnect the first oil chamber (8) from the second oil passage (27). When the abutment surface (52) leaves the main valve core (2), it allows the first oil chamber (8) to connect with the second oil passage (27) through the transition groove (53).

10. A proportional solenoid valve according to claim 7, characterized in that, The valve sleeve (1) has a first oil hole (16), and the main valve core (2) has a second oil hole (28) that communicates with the first oil passage (26). The first oil hole (16) can communicate with the second oil hole (28).

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