A proportional solenoid valve

Abstract

The present invention provides a proportional solenoid valve, belonging to the technical field of solenoid valves. It solves the problem of poor stability of existing proportional solenoid valves. The proportional solenoid valve comprises a valve sleeve with an oil inlet and an oil outlet and a main valve core movably arranged in the valve sleeve, the valve sleeve has a sealing portion and a throttling portion both of which are annularly convex and spaced apart, the sealing portion and the throttling portion are both located between the oil inlet and the oil outlet, the main valve core has a sealing surface and a throttling surface both of which are conical and spaced apart, the smaller diameter ends of the sealing surface and the throttling surface are both facing the oil outlet, when the sealing surface abuts against the sealing portion, the throttling surface is located in 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 leaves the sealing portion for a certain distance, a gap for the flow of oil is formed between the throttling surface and the throttling portion. The proportional solenoid valve has the advantages of making the opening and closing process of the main valve core smooth and free of vibration, and improving the stability of the proportional solenoid valve.

Description

Technical Field

[0001] The invention belongs to the technical field of solenoid valves and relates to a proportional solenoid valve. Background Art

[0002] The hydraulic system of existing engineering machinery includes a gravity lowering mechanism, a proportional solenoid valve and a pressure compensation valve. The proportional solenoid valve and the pressure compensation valve constitute a flow valve, which is used to control the descent speed of gravity lowering, so that the descent speed is only related to the current of the solenoid valve, but has nothing to do with the load of the gravity lowering mechanism, thereby effectively improving the descent operation performance.

[0003] Existing proportional solenoid valves, for example, Chinese patent literature discloses an electromagnetic proportional valve, a flow valve and a hydraulic system [patent number: 202110260851.X; authorization announcement number: CN112901584B]. The electromagnetic proportional valve has a proportional coil installed on the sleeve, an armature slidably arranged in the proportional coil, and a spring arranged between the armature and the sleeve; a first port and a second port are arranged on the valve seat; the main valve core is used for switching between the first port and the second port; one end of the pilot valve core is penetrated by the armature, and the other end is slidably penetrated by 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, and 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, and the first pilot control chamber is connected to the second port through a connecting oil channel, and the force of the hydraulic oil in the first pilot control chamber on the pilot valve core and the force of the hydraulic oil in the second pilot control chamber on the pilot valve core are the same.

[0004] The electromagnetic proportional valve of this structure has a main valve core slidingly arranged in the valve seat, and the main valve core is configured to selectively abut against the position of the valve seat between the first port and the second port, and is used to control the on-off between the first port and the second port. However, the electromagnetic proportional valve of this structure has a sealing surface at the right end of the main valve core, and the valve seat has a sealing portion protruding inward and in an annular shape, and the sealing portion abuts against the sealing surface to form a seal. When the main valve core moves to the left so that the sealing surface leaves the sealing portion, the oil in the first port will quickly flow to the second port, and the oil flow rate changes greatly, and the impact force is large, which causes the main valve core to shake, reducing the stability of the electromagnetic proportional valve. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems in the prior art and propose a proportional solenoid valve, which solves the technical problem of how to make the opening and closing process of the main valve core smooth without shaking, thereby improving the stability of the proportional solenoid valve.

[0006] The objective of the present invention can be achieved through the following technical scheme: a proportional solenoid valve, comprising a valve sleeve having an oil inlet and an oil outlet and a main valve core movably arranged in the valve sleeve, characterized in that the valve sleeve has a sealing portion and a throttling portion, both of which are annularly protruding inwards and arranged at intervals, the sealing portion and the throttling portion are both located between the oil inlet and the oil outlet, the main valve core has a sealing surface and a throttling surface, both of which are conical and arranged at intervals, the smaller diameter ends of the sealing surface and the throttling surface are both facing the oil outlet, when the sealing surface abuts against the sealing portion, the throttling surface is located in 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 leaves the sealing portion for a certain distance, 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 so that the sealing surface no longer abuts against the sealing part, and when the sealing surface leaves the sealing part for a certain distance, since the throttling surface is conical and the end with a smaller diameter of the throttling surface faces the oil outlet, a gap for the flow of oil is formed between the throttling surface and the throttling part. The gap is small, that is, the flow cross-sectional area is small, so that a small amount of oil flows from the oil inlet to the oil outlet. As the main valve core moves, the gap gradually increases until the throttling surface leaves the throttling part, so that the amount of oil flowing from the oil inlet to the oil outlet gradually increases, so that when the proportional solenoid valve is just opened, the change in the oil flow from the oil inlet to the oil outlet is small, reducing the impact force of the oil on the main valve core, making the opening process of the main valve core smooth and without shaking, and improving the stability of the proportional solenoid valve. Similarly, when the proportional solenoid valve is closed, the flow cross-sectional area between the throttling surface and the throttling part gradually decreases, so that the amount of oil flowing from the oil inlet to the oil outlet gradually decreases, so that the change in the oil flow from the oil inlet to the oil outlet is small, and the impact force of the oil on the main valve core is reduced, so that the closing process of the main valve core is smooth and does not shake, and the stability of the proportional solenoid valve is improved. The sealing surface and the throttling surface of the proportional solenoid valve are set separately, which reduces the difficulty of processing, improves the processing accuracy, and can improve the sealing effect of the sealing surface.

[0008] In the above-mentioned proportional solenoid valve, the throttling part 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 the second guide surface is connected to the throttling surface, and when the sealing surface abuts against the sealing part, the first guide surface and the second guide surface are in contact. When the sealing surface abuts against the sealing part, the first guide surface and the second guide surface are in contact, and when the main valve core moves to make the sealing surface leave the sealing part, and the moving distance is within a certain distance, at this time, the first guide surface and the second guide surface are still in contact, and the main valve core is still against the throttling part, so that the impact of the oil on the main valve core can be reduced, and the oil is close to the throttling part and the throttling surface, so that after the sealing surface leaves the sealing part for a certain distance, the oil can pass through the gap between the throttling surface and the throttling part more smoothly, reducing the impact of the oil on the main valve core, making the main valve core open smoothly without shaking, and improving the stability of the proportional solenoid valve.

[0009] In the above-mentioned proportional solenoid valve, there is a first annular receiving groove between the sealing part and the throttling part, and there is a second annular receiving groove 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 is connected to the second receiving groove. The oil passing through the sealing surface can first enter the first receiving groove and the second receiving groove, so that the oil can pass through the gap between the throttling surface and the throttling part more smoothly, reducing the impact force of the oil on the main valve core, making the main valve core open smoothly without shaking, and improving the stability of the proportional solenoid valve.

[0010] In the above-mentioned proportional solenoid valve, the side wall of the sealing part facing the throttling part is a first conical guide wall, the larger diameter end of the first guide wall faces the oil outlet, the groove wall of the second receiving groove close to the second guide surface is a second conical guide wall, the smaller diameter end of the second guide wall faces the oil outlet, when the sealing part moves relatively to the middle of the second receiving groove along the axial direction of the valve sleeve, the second guide surface moves to the middle of the first receiving groove, so that the first guide wall and the second guide wall are arranged relative to each other, so that the sealing part, the second receiving groove, the throttling part and the first receiving groove cooperate to form an S-shaped flow channel for the flow of oil supply liquid between the oil inlet and the oil outlet. This structure allows the oil to flow in the S-shaped curved flow channel, so that the speed and direction of the oil gradually change, which can reduce local pressure fluctuations and vortex formation, reduce the impact of the oil on the main valve core, make the opening and closing process of the main valve core smooth and not shake, and improve the stability of the proportional solenoid valve.

[0011] In the above-mentioned 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 makes the flow cross-sectional area of ​​the gap between the throttling surface and the throttling part smaller, so that the flow rate of the oil changes gradually, improves the stability of the main valve core, and thus improves the stability of the proportional solenoid valve.

[0012] In the above-mentioned 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 above-mentioned proportional solenoid valve, the proportional solenoid valve also includes a magnetic sleeve fixedly connected to the valve sleeve, a moving iron core inserted in the magnetic sleeve, a pilot valve core and a spring, the magnetic sleeve is outer-circuited with a coil, the main valve core is provided with a connecting channel, a first oil channel and a second oil channel, the pilot valve core is provided with a third oil channel, one end of the pilot valve core is connected to the moving iron core, and the other end is inserted in the connecting channel, a first oil chamber is provided between the main valve core and the moving iron core, the oil inlet is connected to the first oil chamber through the first oil channel, the first oil chamber is connected to the oil outlet through the outer end of the connecting channel and the second oil channel, the first oil chamber is connected to the inner end of the connecting channel through the third oil channel, and the two ends of the spring act on the magnetic sleeve and the pilot valve core respectively, or the two ends of the spring act on the magnetic sleeve and the moving iron core respectively. When the coil is energized, it can overcome the elastic force of the spring and drive the moving iron core to move. The size of the coil current can control the opening of the proportional solenoid valve. The oil enters the inner end of the connecting channel from the oil inlet through the first oil channel, the first oil chamber and the third oil channel, so that the oil pressure at both ends of the pilot valve core is the same, avoiding the jitter of the pilot valve core, thereby 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 the oil flows from the oil inlet through the first oil channel, the first oil chamber, the outer end of the connecting channel and the second oil channel to the oil outlet. At this time, the pressure in the first oil chamber will be lower than the pressure at the oil inlet but will not drop very quickly. The pressure at the oil inlet pushes the main valve core to move to the left (open) or to the right (close) linearly, and will not move violently and quickly, ensuring that the opening and closing flow is continuous and linear, making the opening and closing process of the main valve core smooth without jitter, thereby 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 pre-pressure of the spring, that is, adjust the starting current of the proportional solenoid valve.

[0014] In the above-mentioned proportional solenoid valve, the third oil channel includes a main oil channel arranged along the axial direction of the pilot valve core and a branch oil channel arranged along the radial direction of 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, and the groove depth of the connecting groove is 1 / 15-1 / 25 of the diameter of the pilot valve core. The main oil channel is connected to the inner end of the connecting channel through the branch oil channel and the connecting groove.

[0015] In the above-mentioned 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 cut off the connection between the first oil chamber and the second oil channel. When the abutment surface leaves the main valve core, the first oil chamber can be connected to the second oil channel through the transition groove.

[0016] In the above-mentioned proportional solenoid valve, the valve sleeve has a first oil hole, the main valve core has a second oil hole connected to the first oil passage, and the first oil hole can be connected to the second oil hole. The first oil hole and the second oil hole play a role in regulating the oil pressure in the first oil chamber, so that the pilot valve core and the main valve core move smoothly, thereby improving the stability of the proportional solenoid valve.

[0017] Compared with the prior art, the proportional solenoid valve provided by the present invention has the following advantages:

[0018] 1. The throttling surface and the sealing surface of the proportional solenoid valve are arranged at intervals, so that when the main valve core is opened, a gap for oil flow is formed between the throttling surface and the throttling part, and the gap is small, so that a small amount of oil flows from the oil inlet to the oil outlet. As the main valve core moves, the gap gradually increases until the throttling surface leaves the throttling part, so that the amount of oil flowing from the oil inlet to the oil outlet gradually increases, so that the change in the oil flow rate from the oil inlet to the oil outlet is small, the impact force of the oil on the main valve core is reduced, the opening process of the main valve core is smooth without shaking, and the stability of the proportional solenoid valve is improved. The same applies to the closing of the main valve core.

[0019] 2. This proportional solenoid valve is provided with a throttling part and a throttling surface. When it is opened to the maximum, an S-shaped flow channel for the oil flow is formed between the oil inlet and the oil outlet, so that the speed and direction of the oil gradually change, which can reduce local pressure fluctuations and vortex formation, reduce the impact of the oil on the main valve core, make the opening and closing process of the main valve core smooth without shaking, and improve the stability of the proportional solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[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 opened.

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

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

[0024] Figure 5 It is a sectional view of the overall structure of the second embodiment of the proportional solenoid valve.

[0025] In the figure, 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 accommodating groove; 16, first oil hole; 2, main valve core; 21, sealing surface; 22, throttling surface; 23, second guide surface; 24, second accommodating groove; 241, second guide wall; 25, connecting channel; 26, first oil channel; 27, second oil channel; 28, second oil hole; 3, magnetic sleeve; 4, moving iron core; 5, pilot valve core; 51, third oil channel; 511, main oil channel; 512, branch oil channel; 513, connecting groove; 52, abutment surface; 53, transition groove; 6, spring; 7, coil; 8, first oil chamber. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0027] Embodiment 1

[0028] like Figure 1 , Figure 2 , Figure 3 As shown, the proportional solenoid valve includes a valve sleeve 1, a main valve core 2, a magnetic guide 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 in the circumference, and an oil outlet 12 at the end of the valve sleeve 1. The valve sleeve 1 is fixedly connected to the magnetic sleeve 3. The main valve core 2 is movably arranged in the valve sleeve 1. The moving iron core 4, the pilot valve core 5 and the spring 6 are inserted in 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 channel 26 and a second oil channel 27. The pilot valve core 5 has a third oil channel 51. One end of the pilot valve core 5 is connected to the moving iron core 4, and the other end is inserted in 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 along the axial direction of the pilot valve core 5 and a branch oil passage 512 arranged along the radial direction of the pilot valve core 5. A connecting groove 513 is provided on the outer peripheral wall of the inner end of the pilot valve core 5 away from the moving iron core 4. 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 groove depth of the connecting groove 513 is 1 / 20 of the diameter of the pilot valve core 5. In actual production, the groove 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 on the main valve core 2.

[0031] There is a first oil chamber 8 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 passage 25, the transition groove 53 and the second oil passage 27, and the first oil chamber 8 is connected to the inner end of the connecting passage 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, the communication between the first oil chamber 8 and the second oil passage 27 can be cut off, and when the abutting surface 52 leaves the main valve core 2, the first oil chamber 8 can be connected to 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 connected to the first oil passage 26 . When the proportional solenoid valve is at a certain opening, the first oil hole 16 is connected to the second oil hole 28 .

[0033] The valve sleeve 1 has a sealing portion 13 and a throttling portion 14, both of which are annular and inwardly protruding and spaced apart. The sealing portion 13 and the throttling portion 14 are both located between the oil inlet 11 and the oil outlet 12. A first annular accommodating groove 15 is provided between the sealing portion 13 and the throttling portion 14. The throttling portion 14 has a first guide surface 141 provided 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 of which are tapered and spaced apart. The smaller diameter ends of the sealing surface 21 and the throttling surface 22 face the oil outlet 12, and 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 is 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 a second annular receiving groove 24, the second receiving groove 24 is located between the sealing surface 21 and the second guide surface 23, and the first receiving groove 15 is connected to the second receiving groove 24.

[0036] The side wall of the sealing portion 13 facing the throttling portion 14 is a conical first guide wall 131, and the larger diameter end of the first guide wall 131 faces the oil outlet 12. The groove wall of the second accommodating groove 24 close to the second guide surface 23 is a conical second guide wall 241, and the smaller diameter end of the second guide wall 241 faces the oil outlet 12. When the sealing portion 13 moves relatively to the middle of the second accommodating groove 24 along the axial direction of the valve sleeve 1, the second guide surface 23 moves to the middle of the first accommodating 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 portion 13, the second accommodating groove 24, the throttling portion 14 and the first accommodating groove 15 cooperate to form an S-shaped flow channel for the flow of oil supply liquid 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 portion 13 to form a seal, the throttling surface 22 is located in the throttling portion 14, and the first guide surface 141 fits with the second guide surface 23. When the proportional solenoid valve is opened, Figure 2 As shown, when the sealing surface 21 is less than a certain distance away from the sealing portion 13, which is set to 3mm, that is, when the valve core moves 0-3mm to the left, the throttling surface 22 is located in the throttling portion 14, and the first guide surface 141 and the second guide surface 23 are still in contact with each other. The 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 portion 13, that is, when the valve core moves more than 3mm to the left, a gap is formed between the throttling surface 22 and the throttling portion 14 for the oil to flow, and the oil in the first receiving groove 15 and the second receiving groove 24 flows to the oil outlet 12 through the gap. The valve core continues to move to the left, and the flow cross-sectional area of ​​the gap becomes larger and larger until the throttling surface 22 completely leaves the throttling portion 14, as shown in FIG. Figure 3 As shown, the proportional solenoid valve is at its maximum opening, and the sealing portion 13, the second receiving groove 24, the throttling portion 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 portion 14, and then the first guide surface 141 and the second guide surface 23 fit together until the sealing surface 21 abuts against the sealing portion 13.

[0038] Embodiment 2

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

[0040] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0041] Although the terms valve sleeve 1, oil inlet 11, oil outlet 12, sealing portion 13, first guide wall 131, throttling portion 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, oil passage 512, connecting groove 513, abutting surface 52, transition groove 53, spring 6, coil 7, first oil chamber 8 and the like are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for the purpose of more conveniently describing and explaining the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

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 arranged in the valve sleeve (1), characterized in that: The valve sleeve (1) comprises a sealing portion (13) and a throttling portion (14) which are both annularly convex and arranged at intervals, and the sealing portion (13) and the throttling portion (14) are both located between the oil inlet (11) and the oil outlet (12). The main valve core (2) comprises a sealing surface (21) and a throttling surface (22) which are both conical and arranged at intervals, and the smaller diameter ends of the sealing surface (21) and the throttling surface (22) are both facing the oil outlet (12). When the sealing surface (21) abuts against the sealing portion (13), the throttling surface (22) is located in the throttling portion (14) and the outer peripheral wall of the main valve core (2) is in contact with the inner peripheral wall of the throttling portion (14). When the sealing surface (21) is away from the sealing portion (13) by a certain distance, a gap is formed between the throttling surface (22) and the throttling portion (14) for oil to flow.

2. A proportional solenoid valve according to claim 1, characterized in that: The throttling portion (14) has a first guide surface (141) arranged axially along the valve sleeve (1), and the main valve core (2) has a second guide surface (23) arranged axially along 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), and when the sealing surface (21) abuts against the sealing portion (13), the first guide surface (141) fits with the second guide surface (23).

3. A proportional solenoid valve according to claim 2, characterized in that: A first annular receiving groove (15) is provided between the sealing portion (13) and the throttling portion (14), and a second annular receiving groove (24) is provided on the main valve core (2), wherein the second receiving groove (24) is located between the sealing surface (21) and the second guide surface (23), and the first receiving groove (15) is communicated with the second receiving groove (24).

4. A proportional solenoid valve according to claim 3, characterized in that: The side wall of the sealing portion (13) facing the throttling portion (14) is a first conical guide wall (131), the larger diameter end of the first guide wall (131) faces the oil outlet (12), the groove wall of the second accommodating groove (24) close to the second guide surface (23) is a second conical guide wall (241), the smaller diameter end of the second guide wall (241) faces the oil outlet (12), and when the sealing portion (13) is relatively close to the axial direction of 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 relative to each other, so that the sealing portion (13), the second receiving groove (24), the throttling portion (14) and the first receiving groove (15) cooperate to form an S-shaped flow channel for the flow of oil between the oil inlet (11) and the oil outlet (12).

5. A proportional solenoid valve according to claim 1 or 2 or 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 and 50 degrees, and the angle between the throttling surface (22) and the central axis of the valve sleeve (1) is between 10 and 20 degrees.

7. A proportional solenoid valve according to claim 1 or 2 or 3 or 4, characterized in that: The proportional solenoid valve further comprises a magnetic sleeve (3) fixedly connected to the valve sleeve (1), a moving iron core (4) inserted in the magnetic sleeve (3), a pilot valve core (5) and a spring (6); the magnetic sleeve (3) is provided with a coil (7) on its outer shell; the main valve core (2) is provided with a connecting passage (25), a first oil passage (26) and a second oil passage (27); the pilot valve core (5) is provided with 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 is inserted in the connecting passage (25); there is a spring between the main valve core (2) and the moving iron core (4); A first oil chamber (8), 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 passage (25) and the second oil passage (27), the first oil chamber (8) is connected to the inner end of the connecting passage (25) through the third oil passage (51), and 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) comprises a main oil passage (511) arranged along the axial direction of the pilot valve core (5) and a branch oil passage (512) arranged along the radial direction of the pilot valve core (5); a connecting groove (513) is provided on the outer peripheral wall of the inner end of the pilot valve core (5) away from the moving iron core (4); 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 cut off the communication between the first oil chamber (8) and the second oil passage (27). When the abutment surface (52) leaves the main valve core (2), the first oil chamber (8) can be connected to 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), the main valve core (2) has a second oil hole (28) connected to the first oil passage (26), and the first oil hole (16) can be connected to the second oil hole (28).

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