A switch and proportional combined solenoid valve

Abstract

The present invention provides a combined switch and proportional solenoid valve, characterized by an integrated design of a switch solenoid valve and a proportional solenoid valve, with the upper portion being controlled by the switch valve and the lower portion being controlled by the proportional valve. The overall structure primarily comprises a moving iron core 1, a switch solenoid valve excitation coil 2, a solenoid valve main magnetic pole 4, a switch solenoid valve auxiliary magnetic pole 3, a switch solenoid valve return spring 8, a proportional solenoid valve excitation coil 5, a proportional solenoid valve auxiliary magnetic pole 6, an armature 7, and a proportional solenoid valve return spring 9. The combined switch and proportional solenoid valve has multiple operating modes, can be flexibly switched, and is suitable for a variety of working environments. The structure also exhibits low damping force and low eddy current loss, resulting in a good switching response speed. Furthermore, the armature 7 employs a three-section structure of upper cone, lower cone, and cylinder, which significantly suppresses the problem of a rapid increase in electromagnetic force caused by the increased displacement of the armature 7, which would otherwise result in a decrease in the constant-force characteristic of the proportional solenoid valve.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic mechanism design, relates to an electric-mechanical conversion mechanism of an automatic control system, and in particular to a switch and proportional combined electromagnetic valve. Background Art

[0002] A combination on-off and proportional solenoid valve is an automatic control component that uses electromagnetic principles to control the flow of fluids. It is widely used in industrial automation, machinery manufacturing, automobiles, home appliances, and other fields. Traditional solenoid valves are usually only available in one form: a single on-off solenoid valve or a proportional solenoid valve. For example, if there is only a switch solenoid valve, although its structure is simple and the response speed is fast, it cannot achieve precise regulation of flow or pressure; and if there is only a proportional solenoid valve, although it can adjust the flow or pressure according to the input signal to achieve fine control, the response speed of the proportional solenoid valve may be affected by the valve body design; in addition, when the switch solenoid valve is working, the main magnetic pole will generate a large eddy current, which will reduce the dynamic response speed of the solenoid valve on the one hand, and cause temperature rise and energy loss on the other hand (LIU P, ZHANG R, ZHAO Q, et al. Eddy effect and dynamic response of high-speed solenoid valve with composite iron core[J]. Materials, 2023, 16(17): 5823.); and at the end of the stroke of the proportional solenoid valve, the electromagnetic force suddenly increases due to the rapid decrease in magnetic resistance, which makes the constant force characteristic easy to decrease, affecting its control accuracy (Wang Ruiting. Geometric parameter modeling analysis and performance optimization research of moving iron proportional electromagnet[D]. Mechanical Engineering of Wenzhou University, 2019.). Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a switch and proportional combined solenoid valve.

[0004] The object of the present invention is achieved like this:

[0005] A switch and proportional combination solenoid valve is proposed, which is characterized by:

[0006] It includes a moving iron core, a switching solenoid valve excitation coil, a solenoid valve main magnetic pole, a switching solenoid valve auxiliary magnetic pole, a switching solenoid valve return spring, a proportional solenoid valve excitation coil, a proportional solenoid valve auxiliary magnetic pole, an armature, and a proportional solenoid valve return spring;

[0007] The solenoid valve main magnetic poles include the switch solenoid valve main magnetic poles and the proportional solenoid valve main magnetic poles;

[0008] The main magnetic pole of the switch solenoid valve is hollow cylindrical, and the end thereof is provided with four grooves symmetrically distributed along the circumference;

[0009] The main magnetic pole of the proportional solenoid valve is cylindrical, with a stepped hole in the center, which is composed of a circular hole and a tapered hole;

[0010] The auxiliary magnetic pole of the switch solenoid valve is a circular ring structure;

[0011] The auxiliary magnetic pole of the proportional solenoid valve is a cylindrical structure with a circular through hole at the bottom;

[0012] The switching solenoid valve excitation coil is placed between the switching solenoid valve auxiliary magnetic pole and the switching solenoid valve main magnetic pole;

[0013] The proportional solenoid valve excitation coil is placed between the proportional solenoid valve auxiliary magnetic pole and the proportional solenoid valve main magnetic pole;

[0014] The armature structure consists of three sections, which are upper cone, lower cone and cylinder from top to bottom;

[0015] The movable iron core is a disc-shaped structure, and has an annular groove and holes evenly spaced along the circumference on the side close to the main magnetic pole of the switch solenoid valve. The diameter r of the annular groove is larger than the outer diameter R1 of the main magnetic pole of the switch solenoid valve, and smaller than the inner diameter R2 of the auxiliary magnetic pole of the switch solenoid valve.

[0016] The switch solenoid valve return spring is built into the main magnetic pole of the switch solenoid valve and can push the moving iron core to move;

[0017] The proportional solenoid valve reset spring is built into the main magnetic pole stepped hole of the proportional solenoid valve and can push the armature to move.

[0018] When the proportional solenoid valve excitation coil is not energized, only the upper cone of the armature is placed in the stepped hole of the main magnetic pole of the proportional solenoid valve; when the proportional solenoid valve excitation coil is energized, the main magnetic pole of the proportional solenoid valve, the auxiliary magnetic pole of the proportional solenoid valve and the armature are magnetized to generate a main magnetic flux Φ1, and the main magnetic flux Φ1 generates two partial magnetic fluxes Φ2 and Φ3; the partial magnetic flux Φ2 enters the main magnetic pole of the proportional solenoid valve through the air gap between the end face of the armature and the stepped hole of the main magnetic pole of the proportional solenoid valve, generating an axial electromagnetic force F1 acting on the end face of the armature, and the partial magnetic flux Φ3 enters the main magnetic pole of the proportional solenoid valve through the air gap between the upper cone surface of the armature and the main magnetic pole of the proportional solenoid valve, generating an electromagnetic force F2 acting on the upper cone surface of the armature, and the electromagnetic force F2 induces axial and radial electromagnetic component forces F 2z and F 2r At this time, the axial electromagnetic force F1 and the electromagnetic force F2 are the axial electromagnetic force F 2z Together they constitute the armature driving force; as the armature displacement increases, the lower cone of the armature also enters the stepped hole of the main magnetic pole of the proportional solenoid valve. At this time, the main magnetic flux Φ1 also generates a partial magnetic flux Φ4, which enters the main magnetic pole of the proportional solenoid valve through the air gap between the lower cone surface of the armature and the main magnetic pole of the proportional solenoid valve, generating an electromagnetic force F3 acting on the lower cone surface of the armature. The electromagnetic force F3 induces axial and radial electromagnetic component forces F3z and F 3r At this time, the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic force F 2z and electromagnetic force F3 axial electromagnetic force F 3z The three together constitute the armature driving force; due to the electromagnetic force F3 axial electromagnetic component F 3z The three and the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic component force F 2z The direction of action is opposite to that of the armature, which can suppress the problem of rapid increase of electromagnetic force caused by the increase of armature displacement in the later stage, resulting in a decrease in its constant force characteristics.

[0019] When the switch solenoid valve and the proportional solenoid valve work at the same time, current is passed through the switch solenoid valve excitation coil and the proportional solenoid valve excitation coil at the same time, generating magnetic flux Φ and magnetic flux Φ1. Under the action of magnetic flux Φ and Φ1, electromagnetic force is generated, causing the moving iron core and the armature to start moving together along the axial direction of the return springs of the two under the action of the electromagnetic force.

[0020] When the switch solenoid valve works alone, current is passed through the switch solenoid valve excitation coil, and the switch solenoid valve main magnetic pole, switch solenoid valve secondary magnetic pole and movable iron core are magnetized, generating magnetic flux Φ. The magnetic flux Φ starts from the switch solenoid valve main magnetic pole and enters the air gap under the movable iron core, and then goes to the switch solenoid valve secondary magnetic pole, forming a closed loop. At this time, only the switch solenoid valve moves axially along the switch solenoid valve return spring under the action of electromagnetic force, while the armature is in a stationary state.

[0021] When the proportional solenoid valve works alone, the proportional solenoid valve excitation coil is energized while the switch solenoid valve excitation coil is not energized; at this time, only the armature moves axially along the proportional solenoid valve return spring under the action of electromagnetic force while the moving iron core is in a stationary state.

[0022] The advantages of the present invention are:

[0023] 1. The switch and proportional combination solenoid valve proposed in the present invention combines the characteristics of a switch solenoid valve and a proportional solenoid valve, can achieve fast switch control, and can perform precise continuous adjustment. It has multiple working modes and is suitable for a wider range of application scenarios.

[0024] 2. The present invention proposes a switch and proportional combination solenoid valve, in which the main magnetic pole of the switch solenoid valve is provided with a groove, which can increase the resistance formed by the eddy current of the main magnetic pole of the switch solenoid valve and effectively reduce the eddy current loss; at the same time, the annular groove opened on the moving iron core expands the local distance between the moving iron core and the main magnetic pole of the switch solenoid valve, which can reduce the magnitude of the oil film damping force exerted on the moving iron core in the oil environment and accelerate its dynamic response speed.

[0025] 3. The switch and proportional combination solenoid valve proposed in the present invention has an armature structure composed of three sections: an upper cone, a lower cone, and a cylinder. This can suppress the problem of a rapid increase in electromagnetic force caused by the increase in the displacement of the armature in the later stage, which leads to a decrease in its constant force characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural schematic diagram of a switch and proportional combination solenoid valve according to the present invention;

[0027] Figure 2 Schematic diagram of the structure of the moving iron core;

[0028] Figure 3 It is a schematic diagram of the combination of the main magnetic pole of the solenoid valve and the auxiliary magnetic pole of the switch solenoid valve;

[0029] Figure 4 This is the excitation schematic diagram of the proportional solenoid valve in the initial working state;

[0030] Figure 5 This is the excitation diagram of the proportional solenoid valve when its stroke is nearing the end;

[0031] Figure 6 This is a schematic diagram of simultaneous excitation of the switch and proportional solenoid valve;

[0032] Figure 7 This is a schematic diagram of separate excitation of the switch solenoid valve;

[0033] In the figure, 1: moving iron core; 2: switching solenoid valve excitation coil; 3: switching solenoid valve secondary magnetic pole; 4: solenoid valve main magnetic pole; 5: proportional solenoid valve excitation coil; 6: proportional solenoid valve secondary magnetic pole; 7: armature; 8: switching solenoid valve return spring; 9: proportional solenoid valve return spring; 10: hole of moving iron core; 11: annular groove of moving iron core; 12: groove of switching solenoid valve secondary magnetic pole; 41: switching solenoid valve main magnetic pole; 42: proportional solenoid valve main magnetic pole. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0035] like Figure 1-3As shown, the present invention discloses a switch and proportional combination solenoid valve, specifically comprising: a moving iron core 1, a switch solenoid valve excitation coil 2, a solenoid valve main magnetic pole 4, a switch solenoid valve auxiliary magnetic pole 3, a switch solenoid valve return spring 8, a proportional solenoid valve excitation coil 5, a proportional solenoid valve auxiliary magnetic pole 6, an armature 7, and a proportional solenoid valve return spring 9. The solenoid valve main magnetic pole 4 includes a switch solenoid valve main magnetic pole 41 and a proportional solenoid valve main magnetic pole 42. The switch solenoid valve main magnetic pole 41 is a hollow cylinder, and has four symmetrically distributed grooves 12 along the circumferential direction at the end; the proportional solenoid valve main magnetic pole 42 is a cylinder, with a stepped hole in the center, and the stepped hole consists of a circular hole and a tapered hole. The switch solenoid valve auxiliary magnetic pole 3 is a circular ring structure; the proportional solenoid valve auxiliary magnetic pole 6 is a barrel structure, with a circular through hole at the bottom. The switching solenoid valve excitation coil 2 is placed between the switching solenoid valve secondary magnetic pole 3 and the switching solenoid valve main magnetic pole 41; the proportional solenoid valve excitation coil 5 is placed between the proportional solenoid valve secondary magnetic pole 6 and the proportional solenoid valve main magnetic pole 42. The armature 7 structure consists of three sections: an upper cone, a lower cone, and a cylinder, from top to bottom. The moving iron core 1 is a disc-shaped structure, with an annular groove 11 on the side close to the switching solenoid valve main magnetic pole 41 and holes 10 evenly spaced along the circumference. The center diameter r of the annular groove is larger than the outer diameter R1 of the switching solenoid valve main magnetic pole, but smaller than the inner diameter R2 of the switching solenoid valve secondary magnetic pole 3. The switching solenoid valve return spring 8 is built into the switching solenoid valve main magnetic pole 41 to drive the moving iron core 1; the proportional solenoid valve return spring 9 is built into the stepped hole of the proportional solenoid valve main magnetic pole 42 to drive the armature 7.

[0036] During operation, the movable iron core 1 is located in an oil environment. The annular groove 11 and hole 10 formed therein not only increase the local distance between the movable iron core and the main magnetic pole of the switching solenoid valve, but also provide an additional flow channel for the oil, thereby reducing the oil pressure on the surface of the movable iron core and the oil damping force, thereby helping to improve the response speed of the switching solenoid valve. Furthermore, the groove 12 provided in the secondary magnetic pole 3 of the switching solenoid valve interrupts the closed loop of eddy currents induced during operation in the main magnetic pole 41 of the switching solenoid valve, effectively increasing the eddy current circuit resistance, thereby reducing eddy current losses and improving the response speed of the switching solenoid valve.

[0037] Depend on Figure 4It can be seen that when the proportional solenoid valve excitation coil 5 is not energized, only the upper cone of the armature 7 is placed in the stepped hole of the proportional solenoid valve main magnetic pole; when the proportional solenoid valve excitation coil 5 is energized, the proportional solenoid valve main magnetic pole 42, the proportional solenoid valve auxiliary magnetic pole 6 and the armature 7 are magnetized, generating a main magnetic flux Φ1, and the main magnetic flux Φ1 generates two partial magnetic fluxes Φ2 and Φ3; the partial magnetic flux Φ2 enters the proportional solenoid valve main magnetic pole 42 through the air gap between the end face of the armature 7 and the stepped hole of the proportional solenoid valve main magnetic pole 42, generating an axial electromagnetic force F1 acting on the end face of the armature 7, and the partial magnetic flux Φ3 enters the proportional solenoid valve main magnetic pole 42 through the air gap between the upper cone of the armature 7 and the proportional solenoid valve main magnetic pole 42, generating an electromagnetic force F2 acting on the upper cone surface of the armature 7, and the electromagnetic force F2 induces axial and radial electromagnetic component forces F 2z and F 2r At this time, the axial electromagnetic force F1 and the electromagnetic force F2 are the axial electromagnetic force F 2z At this time, in the magnetic flux Φ3 circuit, the working air gap magnetic resistance between the upper cone of the armature 7 and the main magnetic pole 42 of the proportional solenoid valve gradually decreases, and the degree of reduction is greater than the working air gap magnetic resistance between the end face of the armature 7 and the main magnetic pole 42 of the proportional solenoid valve in the magnetic flux Φ2 circuit. This makes the magnetic flux Φ2 gradually decrease and the magnetic flux Φ3 gradually increase, resulting in a decrease in F1 acting on the end face of the armature 7 and a decrease in the axial electromagnetic force F acting on the upper cone of the armature 7. 2z Therefore, the output electromagnetic force obtained by the superposition of the two forces remains basically unchanged within a working stroke, thus producing a horizontal characteristic, which is also called a constant force characteristic.

[0038] Depend on Figure 5 It can be seen that as the lower conical portion of the armature 7 also enters the stepped hole of the main magnetic pole 42 of the proportional solenoid valve, the distance between the armature 7 and the proportional solenoid valve is further reduced, and the working air gap magnetic resistance between the end face of the armature 7 and the proportional solenoid valve is also significantly reduced, which also increases the magnetic flux Φ2, thereby increasing the axial force F1. Therefore, at the end of the working stroke, the output electromagnetic force increases, and eventually leads to the degradation of the overall constant force characteristic. However, due to the entry of the lower conical portion of the armature 7, the main magnetic flux Φ1 now generates another partial magnetic flux Φ4. The partial magnetic flux Φ4 enters the main magnetic pole 42 of the proportional solenoid valve through the air gap between the lower conical surface of the armature 7 and the main magnetic pole 42 of the proportional solenoid valve, generating an electromagnetic force F3 acting on the lower conical surface of the armature 7. The electromagnetic force F3 induces axial and radial electromagnetic component forces F 3z and F 3r At this time, the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic force F 2z and electromagnetic force F3 axial electromagnetic force F 3z The three together constitute the armature driving force. 3z The three and the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic component force F 2zThe direction of action is opposite to that of the armature 7, so it can suppress the problem that the electromagnetic force caused by the increase in displacement of the armature 7 in the later stage becomes rapidly larger and causes its constant force characteristics to decrease.

[0039] Depend on Figure 6 It can be seen that when the switch and the proportional solenoid valve work at the same time, current is passed through the switch solenoid valve excitation coil 2 and the proportional solenoid valve excitation coil 5 at the same time, generating magnetic flux Φ and magnetic flux Φ1. Under the action of the magnetic fluxes Φ and Φ1, electromagnetic force is generated, causing the moving iron core 1 and the armature 7 to start moving together along the axial direction of their return springs under the action of the electromagnetic force.

[0040] Depend on Figure 7 As can be seen, the switch solenoid valve operates independently. When current flows through the switch solenoid valve excitation coil 2, the switch solenoid valve main magnetic pole 41, the switch solenoid valve secondary magnetic pole 3, and the movable iron core 1 are magnetized, generating a magnetic flux Φ. This magnetic flux Φ originates from the switch solenoid valve main magnetic pole, enters the air gap below the movable iron core 1, and then flows to the switch solenoid valve secondary magnetic pole 3, forming a closed loop. As the current in the switch solenoid valve excitation coil 2 increases, the electromagnetic force gradually increases. When the electromagnetic force is greater than the load force applied to the switch solenoid valve return spring 8, the movable iron core 1 begins to move toward the switch solenoid valve main magnetic pole 41, ultimately completing the pull-in movement. When the switch solenoid valve excitation coil 8 is de-energized, the electromagnetic force applied to the movable iron core 1 gradually decreases. Under the combined action of the external load force and the switch solenoid valve return spring 8, the movable iron core 1 moves away from the switch solenoid valve main magnetic pole 41, completing the release process.

[0041] When the proportional solenoid valve works alone, the proportional solenoid valve excitation coil 5 is energized and the switch solenoid valve excitation coil 2 is not energized; at this time, only the armature 7 moves axially along the proportional solenoid valve return spring 9 under the action of electromagnetic force, and the moving iron core is in a stationary state.

[0042] In summary, by designing the armature 7 into a three-section structure consisting of an upper cone, a lower cone, and a cylinder, respectively, and by providing a hole 10 and an annular groove 11 in the movable iron core 1, and a groove 12 in the main magnetic pole 41 of the switch solenoid valve, and integrating the switch and proportional solenoid valve, the solenoid valve has multiple operating modes, adapting to a wider range of application scenarios, while also improving its switch response speed and proportional control accuracy. The technical features disclosed in this invention are practical, feasible, and significantly innovative and effective.

[0043] Finally, it should be noted that the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A switch and proportional combination solenoid valve, specifically comprising: A moving iron core (1), a switching solenoid valve excitation coil (2), a solenoid valve main magnetic pole (4), a switching solenoid valve auxiliary magnetic pole (3), a switching solenoid valve return spring (8), a proportional solenoid valve excitation coil (5), a proportional solenoid valve auxiliary magnetic pole (6), an armature (7), and a proportional solenoid valve return spring (9), characterized in that: The solenoid valve main magnetic pole (4) comprises a switch solenoid valve main magnetic pole (41) and a proportional solenoid valve main magnetic pole (42); The main magnetic pole (41) of the switch solenoid valve is in the shape of a hollow cylinder, and has four grooves symmetrically distributed along the circumference at its end; The main magnetic pole (42) of the proportional solenoid valve is cylindrical, with a stepped hole in the center, and the stepped hole is composed of a circular hole and a tapered hole; The auxiliary magnetic pole (3) of the switch solenoid valve is a circular ring structure; The auxiliary magnetic pole (6) of the proportional solenoid valve is a cylindrical structure with a circular through hole at the bottom; The switch solenoid valve excitation coil (2) is placed between the switch solenoid valve auxiliary magnetic pole (3) and the switch solenoid valve main magnetic pole (41); The proportional solenoid valve excitation coil (5) is placed between the proportional solenoid valve auxiliary magnetic pole (6) and the proportional solenoid valve main magnetic pole (42); The armature (7) structure consists of three sections, which are upper cone, lower cone and cylinder from top to bottom; The moving iron core (1) is a disc-shaped structure, and a ring-shaped groove is formed on a side close to the main magnetic pole (41) of the switch solenoid valve, and holes are formed along the circumference at even intervals. The switch solenoid valve return spring (8) is built into the switch solenoid valve main magnetic pole (41) to push the iron core (1) to move; The proportional solenoid valve reset spring (9) is built into the stepped hole of the proportional solenoid valve main magnetic pole (42) to push the armature (7) to move.

2. A switch and proportional combined solenoid valve according to claim 1, characterized in that: The diameter r of the annular groove of the moving iron core (1) is larger than the outer diameter R1 of the main magnetic pole (41) of the switch electromagnetic valve, and smaller than the inner diameter R2 of the auxiliary magnetic pole (3) of the switch electromagnetic valve.

3. A switch and proportional combination solenoid valve according to claim 1, characterized in that: When the proportional solenoid valve excitation coil (5) is not energized, only the upper cone of the armature (7) is placed in the stepped hole of the proportional solenoid valve main magnetic pole (42); when the proportional solenoid valve excitation coil (5) is not energized, the proportional solenoid valve main magnetic pole (42), the proportional solenoid valve auxiliary magnetic pole (6) and the armature (7) are magnetized to generate a main magnetic flux Φ1, and the main magnetic flux Φ1 generates two partial magnetic fluxes Φ2 and Φ3; the partial magnetic flux Φ2 enters the proportional solenoid valve main magnetic pole (42) through the air gap between the end face of the armature (7) and the stepped hole of the proportional solenoid valve main magnetic pole (42), generating an axial electromagnetic force F1 acting on the end face of the armature (7); the partial magnetic flux Φ3 enters the proportional solenoid valve main magnetic pole (42) through the air gap between the upper cone of the armature (7) and the proportional solenoid valve main magnetic pole (42), generating an electromagnetic force F2 acting on the upper cone of the armature (7), and the electromagnetic force F2 induces axial and radial electromagnetic component forces F 2z and F 2r At this time, the axial electromagnetic force F1 and the electromagnetic force F2 are the axial electromagnetic force F 2z Together they constitute the armature driving force; as the displacement of the armature (7) increases, the lower cone of the armature (7) also enters the stepped hole of the main magnetic pole (42) of the proportional solenoid valve, at which time the main magnetic flux Φ1 generates another partial magnetic flux Φ4, which enters the main magnetic pole (42) of the proportional solenoid valve through the air gap between the lower cone of the armature (7) and the main magnetic pole (42), generating an electromagnetic force F3 acting on the lower cone of the armature (7), and the electromagnetic force F3 induces axial and radial electromagnetic component forces F 3z and F 3r At this time, the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic force F 2z and electromagnetic force F3 axial electromagnetic force F 3z The three together constitute the armature driving force; the electromagnetic force F3 and the axial electromagnetic force F 3z The three and the axial electromagnetic force F1, electromagnetic force F2 and axial electromagnetic component force F 2z The direction of action is opposite to that of the armature (7), which suppresses the rapid increase of the electromagnetic force when the displacement of the armature (7) increases in the later stage.

4. A switch and proportional combination solenoid valve according to claim 1, characterized in that: When the switch and the proportional solenoid valve are working simultaneously, the switch solenoid valve excitation coil (2) and the proportional solenoid valve excitation coil (5) are energized at the same time, and the moving iron core (1) and the armature (7) simultaneously move axially along the return springs of the two under the action of electromagnetic force; When the switch solenoid valve works alone, the switch solenoid valve excitation coil (2) is energized while the proportional solenoid valve excitation coil (5) is not energized, and only the moving iron core (1) moves axially along the switch solenoid valve return spring (8) under the action of electromagnetic force while the armature (7) is in a stationary state; When the proportional solenoid valve works alone, the proportional solenoid valve excitation coil (5) is energized while the switch solenoid valve excitation coil (2) is not energized, and only the armature (7) moves axially along the proportional solenoid valve return spring (9) under the action of electromagnetic force while the moving iron core is in a stationary state.

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