JP2010169206A - Non leak shockless solenoid proportional control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a hydraulic circuit which prevents the variation of shock relaxing performance due to a change of working fluid temperature, reduce machining costs and acquire proportional control and non-leak state at valve closing of a solenoid valve. <P>SOLUTION: A non-leak shockless solenoid proportional control valve is equipped with a projection 7g formed on an end surface of a plunger 7 and provided with a truncated conical sealing surface 7h and a truncated conical seat surface 1d formed in an inlet of a flow outlet 2 of a flow-in chamber 1 and liquid-tightly fitted with the truncated conical sealing surface 7h so as to be separable therefrom. A base part of the truncated conical sealing surface 7h is exposed from the truncated conical seat surface 1d to the inside of the inflow chamber 1c in a fitted state with the truncated conical seat surface 1d. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a non-leak type shockless solenoid valve, and more particularly to a shockless solenoid valve that enables proportional control.

  As a conventional non-leak type shockless solenoid valve, the SV series described in Non-Patent Document 1 is known, and this solenoid valve is formed with a shallow circular recess 1a as shown in a cross section in FIG. The main body 1 is provided with a truncated conical protrusion 1b formed at the center of the recess 1a, an outlet 2 at the center of the protrusion 1b, and an inlet 3 at the side of the protrusion 1b. And a disc-shaped base 4 as a lid member that is fixed in a liquid-tight manner to the recess 1a and defines an inflow chamber 1c in the recess 1a, and one end of a through hole in the center of the base 4 A sleeve 5 liquid-tightly fixed, a fixed shaft 6 liquid-tightly fixed to the other end of the sleeve 5, and a plunger slidably inserted into the sleeve 5 with a slight gap therebetween 7 and the plunger 7 and the fixed shaft 6 are inserted between the A plunger assembly 9 having a spring 8 that constantly biases the nanger 7 toward the inflow chamber 1c is provided. Further, a flux plate 10 that collects magnetic flux inserted through the sleeve 5 and the fixed shaft 6 and a coil 11 are wound. And a housing 13 which is covered with the flux plate 10 and the bobbin 12 and is fastened and fixed to the fixed shaft 6 with bolts 14.

  Here, as schematically shown in an enlarged view of a part of the solenoid valve in FIG. 6, the tip 7 a of the plunger 7 is provided with a conical protrusion 7 b that enters the outlet 2, and is fixed. Between the base end portion 6 a of the shaft 6 and the rear end portion 7 c of the plunger 7, viscous working oil enters from the inflow chamber 1 c through the gap between the sleeve 5 and the plunger 7. With this configuration, when the plunger 7 is retracted from the outlet 2 by a magnetic force by energizing the coil 11, and the plunger 7 is advanced toward the outlet 2 by the spring 8 by interrupting the energization of the coil 11, As the conical protrusion 7b gradually opens and closes the outlet 2 with the forward and backward movement, the hydraulic oil that has entered between the base end portion 6a of the fixed shaft 6 and the rear end portion 7c of the plunger 7 becomes the sleeve. By entering and exiting the inflow chamber 1c through the gap between the plunger 5 and the plunger 7, the shock of opening and closing of the electromagnetic valve is mitigated. When the plunger 7 is in the advanced limit position, the hydraulic pressure of the hydraulic oil applied from the inflow port 3 depends on the area difference between the pressure receiving surface on the inflow chamber 1c side of the front end 7a of the plunger 7 and the pressure receiving surface on the fixed shaft 6 side of the rear end 7c. Since the flat lower end surface around the protrusion 7b is liquid-tightly pressed against the flat tip surface of the protrusion 1b around the outlet 2 by the differential pressure, the outlet 2 is completely closed. When the valve is closed, it enters a non-leak state in which hydraulic fluid does not leak.

  In addition, as a conventional shockless solenoid valve, for example, a spool type is generally known. This solenoid valve is a plunger that moves forward and backward by the magnetic force of a coil, and slides the spool against the main body to thereby move the outer periphery of the spool. The valve is opened and closed on the surface.

Fine Sinter Co., Ltd. Catalog No. published in January 2005 Pages 11-14 of KC-0501 "TSM Hydraulic Equipment Series"

  By the way, the above-mentioned conventional non-leak shockless solenoid valve depends on not only the conical protrusion 7b but also the viscosity of the hydraulic oil to obtain the shock mitigation performance, so that the plunger changes when the hydraulic oil temperature changes. 7 has a problem that the operating speed of the motor 7 is changed, and the shock mitigation performance varies. In addition, since the hydraulic oil enters and exits through the minute flow path between the sleeve 5 and the plunger 7, there is a problem that high machining accuracy is required for these parts and the machining cost increases.

  On the other hand, since the latter conventional shockless solenoid valve is of a spool type, there is a problem that hydraulic oil leaks from the gap between the main body and the spool, and the structure does not become a non-leak state. When trying to obtain a non-leak state, it is necessary to combine with a shut-off valve, and there is a problem that the cost of the hydraulic circuit increases.

  An object of the present invention is to advantageously solve the above-mentioned problems. A non-leak shockless electromagnetic proportional control valve according to the present invention includes a main body having a recess having an outlet and an inlet and an opening in the recess. A lid member that is liquid-tightly fixed and defines an inflow chamber in the recess, a sleeve that is liquid-tightly fixed at one end to the through-hole of the lid member, and liquid-tightly fixed to the other end of the sleeve A fixed shaft, a plunger slidably fitted in the sleeve, and a spring that is interposed between the plunger and the fixed shaft and constantly urges the plunger toward the inflow chamber. A solenoid valve comprising: a coil fitted around the sleeve and the fixed shaft; and a flux plate interposed between the lid member and the coil to direct the magnetic flux of the coil toward the plunger. smell A convex portion having a truncated conical sealing surface formed on an end surface of the plunger facing the inflow chamber, and the truncated conical seal formed at an inlet of the outlet of the inflow chamber. A frustoconical seating surface, which is separably liquid-tightly fitted to the surface, and the frustoconical shape in a fitted state between the frustoconical sealing surface and the frustoconical seating surface. A base portion of the sealing surface is exposed from the truncated conical seating surface to the inflow chamber.

  In the non-leak shockless electromagnetic proportional control valve according to the present invention, the start of energization of the coil and the increase of the energization amount in the state where the hydraulic oil has flowed from the inlet to the inflow chamber and between the plunger and the fixed shaft. The plunger is gradually retracted from the outlet by a magnetic force against the spring by the spring, and the plunger is directed to the outlet by a spring without resisting the magnetic force by reducing the energization amount to the coil or by deactivating the energization. As the plunger moves forward and backward, the gap between the truncated cone-shaped sealing surface of the convex portion of the plunger and the truncated cone-shaped seating surface of the inlet of the outlet gradually opens and closes Therefore, the shock of opening and closing the solenoid valve is alleviated. Further, as the plunger moves forward and backward, the hydraulic oil that has entered between the fixed shaft and the plunger enters and exits through the gap between the sleeve and the plunger. When the plunger is at the advanced limit position, the hydraulic pressure of the hydraulic oil applied from the inlet is determined by the pressure difference due to the area difference between the inlet chamber side pressure receiving surface and the fixed shaft side pressure receiving surface of the plunger and the pressing force of the spring. Since the conical sealing surface is pressed against the truncated conical seating surface in a fluid-tight manner, the outlet is completely closed. A non-leak state that does not occur. Moreover, since the base of the frustoconical sealing surface is exposed to the inflow chamber from the frustoconical seating surface in a closed state where the frustoconical sealing surface and the frustoconical seating surface are fitted, The inflow chamber side pressure receiving surface of the plunger extends to the exposed base portion, and the area difference between the inflow chamber side pressure receiving surface and the fixed shaft side pressure receiving surface of the plunger is slight.

  Therefore, according to the non-leak shockless electromagnetic proportional control valve of the present invention, the outlet is gradually opened and closed by the change in the magnetic force of the coil and the spring, and the pressure-receiving surface on the inflow chamber side of the plunger that opposes the magnetic force of the coil when the valve is opened. Since the pressure due to the pressure difference between the bearing and the fixed shaft side pressure receiving surface is made smaller than the spring pressing force due to a slight area difference between the pressure receiving surfaces, shock relaxation performance is obtained. Variations in the relaxation performance can be prevented, and the machining accuracy of the sleeve and plunger can be lowered to reduce the machining cost. Moreover, when this control valve is closed, it becomes a non-leak state that does not cause hydraulic oil leakage. Therefore, when the proportional control of the solenoid valve and the non-leak state when the valve is closed are required, it is not necessary to combine with the shut-off valve. It is possible to reduce the.

  In the non-leak shockless electromagnetic proportional control valve of the present invention, it is preferable that the plunger is formed with an oil passage that communicates the clearance between the plunger and the fixed shaft and the inflow chamber. . In this way, the hydraulic oil can easily flow between the gap between the plunger and the fixed shaft and the inflow chamber when the plunger moves forward and backward, so the shock mitigating performance can be achieved by changing the hydraulic oil temperature. It is possible to more effectively prevent the variation.

  In the non-leak shockless electromagnetic proportional control valve according to the present invention, it is preferable that an adjustment screw for adjusting a preload of the spring is inserted into the fixed shaft in a liquid-tight manner and screwed. In this way, the preload of the spring can be easily adjusted according to the hydraulic pressure of the hydraulic oil without disassembling the electromagnetic proportional control valve.

  Furthermore, in the non-leak shockless electromagnetic proportional control valve according to the present invention, it is preferable that the end portions of the plunger and the fixed shaft facing each other are formed with truncated cone surfaces in a direction of fitting with each other. In this way, it is possible to reduce the change in the distance from the fixed shaft due to the forward and backward movement of the plunger, and it is possible to easily control the plunger's attractive force by the magnetic force.

It is sectional drawing which shows one Example of the non-leak shockless electromagnetic proportional control valve of this invention. It is explanatory drawing which expands and schematically shows a part of non-leak shockless electromagnetic proportional control valve of the said Example. It is a circuit diagram which shows an example of the hydraulic circuit using the non-leak shockless electromagnetic proportional control valve of the said Example. It is explanatory drawing which shows the control example of the non-leak shockless electromagnetic proportional control valve of the said Example at the time of operating a hydraulic cylinder with the hydraulic circuit shown in FIG. It is sectional drawing which shows an example of the conventional non-leak shockless solenoid valve. It is explanatory drawing which expands and shows a part of said conventional solenoid valve typically.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the non-leak shockless electromagnetic proportional control valve of the present invention. FIG. 2 is an enlarged view of a part of the non-leak shockless electromagnetic proportional control valve of the above embodiment. FIG. 3 is an explanatory diagram schematically showing a circuit diagram showing an example of a hydraulic circuit using the non-leak shockless electromagnetic proportional control valve of the above embodiment, and FIG. 4 shows a hydraulic cylinder in the hydraulic circuit shown in FIG. It is explanatory drawing which shows the example of control of the non-leak shockless electromagnetic proportional control valve of the said Example at the time of making it operate | move, In the figure, the part similar to the prior art example shown in FIG.5, 6 is shown with the same code | symbol as it. .

  In the non-leak shockless electromagnetic proportional control valve of this embodiment, as shown in a cross section in FIG. 1, a shallow circular recess 1a is formed, and a frustoconical protrusion 1b is formed at the center of the recess 1a. The main body 1 is provided with an outlet 2 at the center of the projecting portion 1b and an inlet 3 at the side of the projecting portion 1b, and is screwed and fixed in a liquid-tight manner to the concave portion 1a through, for example, an O-ring. And a plunger assembly 9 having a disc-like base portion 4 as a lid member defining an inflow chamber 1c in the recess 1a. The plunger assembly 9 has a central portion of the base portion 4 in addition to the base portion 4. A sleeve 5 whose one end is liquid-tightly fixed to the through hole 4a, for example, by brazing, a fixed shaft 6 made of a magnetic material, which is liquid-tightly fixed to the other end of the sleeve 5, for example, by brazing, and the sleeve 5 Leave a slight gap inside A plunger 7 made of a magnetic material slidably inserted, and a front end portion (end portion on the inflow chamber 1c side) from a rear end portion (end portion on the fixed shaft 6 side) 7c along the central axis of the plunger 7 ) The spring 8 accommodated in the recess 7d formed toward 7a and the through hole 6b formed along the central axis of the fixed shaft 6 are inserted in a liquid-tight manner, for example, via an O-ring. An adjustment screw 14 in which a male screw 14 a at the head is screwed to a female screw 6 c in the through hole 6 b, and this is also accommodated in the recess 7 d of the plunger 7, and between the tip of the adjustment screw 14 and the spring 8. And a disc-like spacer 15 inserted therein.

  As a result, the spring 8 is inserted between the fixed shaft 6 and the plunger 7 and constantly urges the plunger 7 toward the inflow chamber 1 c, and the adjusting screw 14 is screwed in the through hole 6 b of the fixed shaft 6. The spring 8 is compressed through the spacer 15 to increase the preload of the spring 8, and the spring 8 is extended through the spacer 15 when rotated in the return direction in the through hole 6 b of the fixed shaft 6. Thus, by reducing the preload of the spring 8, the preload of the spring 8 is adjusted so as to press the plunger 7 with a pressing force corresponding to the hydraulic pressure of the hydraulic oil supplied to the inlet 3.

  The plunger 7 here is a groove-shaped oil passage 7e formed on the outer peripheral surface of the plunger 7 and extending in the axial direction of the plunger 7, and a communication passage 7f for communicating the oil passage 7e with the recess 7d. As a result, the hydraulic oil that has flowed into the inflow chamber 1c from the inflow port 3 passes through the oil passage 7e and the communication passage 7f, and the rear end portion 7c of the plunger 7 of the fixed shaft 6 The gap between the base end portion 6a and the concave portion 7d of the plunger 7 enters.

  The non-leak shockless electromagnetic proportional control valve of this embodiment further includes a coil assembly 16 that is inserted into and fixed to the sleeve 5 and the fixed shaft 6, and the coil assembly 16 is, for example, a flux plate that collects magnetic flux. A coil 11 is wound between both end plates 13a and 13b of a housing 13 obtained by bending a thick magnetic plate serving as a role into a U shape, and the periphery of the coil 11 is sealed with a resin 19. A bobbin 12 and a disc spring 18 that presses and fixes the bobbin 12 to the upper end plate 13b in FIG. 1 are interposed, and among the two end plates of the housing 13, the lower end plate 13a in FIG. A through-hole 13c through which the sleeve 5 and the fixed shaft 6 can pass is formed, and a small-diameter tip of the fixed shaft 6 (reverse to the plunger 7 side) is formed on the upper end plate 13b. The end) 6d through hole 13d of the inner diameter of the large diameter portion is not placed in the can through the sleeve 5 and the fixed shaft 6 is formed.

  As a result, the coil assembly 16 first inserts the sleeve 5 and the fixed shaft 6 from the tip end portion 6d side into the through hole 13c of the lower end plate 13a of the housing 10 and then into the disc spring 18 and the bobbin 12. Finally, the tip portion 6d is inserted into the through hole 13d of the upper end plate 13b, and the step portion between the large diameter portion and the small diameter tip portion 6d of the fixed shaft 6 is brought into contact with the upper end plate 13b. The upper end plate 13b is fixed to the fixed shaft 6 with a nut 20 screwed into a male screw 6e provided around the tip portion 6d, thereby being fixed to the plunger assembly 9.

  In the non-leak shockless electromagnetic proportional control valve of this embodiment, as shown schematically in an enlarged view of a part of FIG. 2, a convex portion is formed at the center of the tip portion of the plunger 7 facing the concave portion 1a of the main body 1. 7g is provided, a truncated conical sealing surface 7h is formed around the tip of the convex portion 7g, and a truncated conical seating surface 1d is formed at the inlet of the outlet 2 at the center of the projecting portion 1b of the main body 1. The frustoconical sealing surface 7 h and the frustoconical seating surface 1 d are liquid-tightly fitted by the advance movement of the plunger 7 toward the outlet 2. The portion of the truncated conical sealing surface 7h fitted with the truncated conical seating surface 1d in the fitted state of the truncated conical sealing surface 7h and the truncated conical seating surface 1d. The base portion located radially outward is protruded from the frustoconical seat surface 1d and exposed in the inflow chamber 1c.

  Furthermore, in the non-leak shockless electromagnetic proportional control valve of this embodiment, as shown in FIG. 1, the rear end portion 7c of the plunger 7 and the base end portion 6a of the fixed shaft 6 opposed to the rear end portion 7c, A frustoconical surface in the direction of fitting with each other, that is, a convex frustoconical surface is formed at the rear end portion 7c of the plunger 7, and a concave frustoconical surface is formed at the base end portion 6a of the fixed shaft 6. .

  In the non-leak shockless electromagnetic proportional control valve of this embodiment having such a configuration, the inflow chamber 1c and the rear end portion 7c of the plunger 7 and the base end portion 6a of the fixed shaft 6 and the plunger are provided. In the state where the hydraulic oil has flowed into the recess 7d of FIG. 7, the plunger 7 is gradually retreated from the outlet 2 by the magnetic force against the spring 8 by starting energization of the coil 11 and increasing the energization amount. If the plunger 7 is gradually advanced toward the outlet 2 by the spring 8 against the magnetic force by decreasing the energization amount to 11 or without resisting the magnetic force by cutting off the energization, the plunger 7 protrudes as the plunger 7 moves forward and backward. By gradually opening and closing the gap between the truncated conical sealing surface 7h of the portion 7g and the truncated conical seating surface 1d at the inlet of the outlet 2, the shock of opening and closing of the electromagnetic valve is alleviated. Further, as the plunger 7 moves back and forth, the hydraulic oil that has entered between the base end portion 6 a of the fixed shaft 6 and the rear end portion 7 c of the plunger 7 and in the concave portion 7 d of the plunger 7 is formed between the sleeve 5 and the plunger 7. In addition to the clearance, the oil passage 7e on the outer peripheral surface of the plunger 7 and the communication passage 7f that connects the oil passage 7e and the recess 7d enter and exit.

  1 and 2, the plunger 7 receives the hydraulic pressure of the hydraulic oil applied from the inflow port 3 and receives the pressure on the inlet chamber 1c side of the front end 7a of the plunger 7 and the pressure on the fixed shaft 6 side of the rear end 7c. With the pressure difference due to the area difference from the surface and the pressing force of the spring 8, the truncated conical sealing surface 7h is liquid-tightly pressed against the truncated conical seat surface 1d, and the outlet 2 is completely closed. Therefore, the non-leak shockless electromagnetic proportional control valve of this embodiment is in a non-leak state in which hydraulic fluid does not leak when the valve is closed. In addition, in a valve-closed state in which the frustoconical sealing surface 7h and the frustoconical seating surface 1d are fitted, the base of the frustoconical sealing surface 7h comes out of the frustoconical seating surface 1d. Since it is exposed in the inflow chamber 1c, the pressure receiving surface on the inflow chamber 1c side of the plunger 7 extends to the exposed base portion, and the area difference between the pressure receiving surface on the inflow chamber 1c side of the plunger 7 and the pressure receiving surface on the fixed shaft 6 side is slight. It will be a thing.

  Therefore, according to the non-leak shockless electromagnetic proportional control valve of this embodiment, the plunger 7 gradually opens and closes the outlet 2 by the change in the magnetic force of the coil 11 and the spring 8 and opposes the magnetic force of the coil 11 when the valve is opened. Since the pressing force due to the differential pressure between the pressure receiving surface on the inflow chamber 1c side and the pressure receiving surface on the fixed shaft 6 side is made smaller than the pressing force of the spring 8 due to a slight area difference between the pressure receiving surfaces, shock relaxation performance is obtained. The shock relaxation performance can be prevented from varying due to the change in the temperature of the hydraulic oil, the processing accuracy of the sleeve 5 and the plunger 7 can be reduced, and the processing cost can be reduced, and the control valve of this embodiment can be closed by itself. When the valve is in a non-leak state where no hydraulic oil leaks, it is combined with a shut-off valve to determine the proportional control of the solenoid valve and the non-leak state when the valve is closed. It is possible to reduce the construction cost of the hydraulic circuit to eliminate the need.

  Furthermore, according to the non-leak shockless electromagnetic proportional control valve of this embodiment, the plunger 7 includes a gap between the rear end portion 7c of the plunger 7 and the base end portion 6a of the fixed shaft 6, and the inflow chamber 1c. Since the oil passage 7f is formed to communicate the hydraulic fluid, the hydraulic oil is moved between the rear end portion 7c of the plunger 7 and the base end portion 6a of the fixed shaft 6 and the inflow chamber 1c when the plunger 7 moves forward and backward. Therefore, it is possible to effectively prevent variation in shock mitigation performance due to changes in the oil temperature of the hydraulic oil. In addition, since a communication passage 7f that connects the oil passage 7f and the concave portion 7d of the plunger 7 is also formed, the hydraulic oil is transferred to the concave portion 7d of the plunger 7 and the inflow chamber 1c when the plunger 7 moves forward and backward. Therefore, it is possible to more effectively prevent the shock relaxation performance from varying due to a change in the oil temperature of the hydraulic oil.

  Further, according to the non-leak shockless electromagnetic proportional control valve of this embodiment, the adjusting screw 14 for adjusting the preload of the spring 8 is inserted into the fixed shaft 6 in a liquid-tight manner and screwed. Even if the electromagnetic proportional control valve of the embodiment is not disassembled, the preload of the spring 8 can be easily adjusted in accordance with the hydraulic pressure of the hydraulic oil.

  Then, according to the non-leak shockless electromagnetic proportional control valve of this embodiment, the end portions 7c and 6a of the plunger 7 and the fixed shaft 6 facing each other are formed with truncated cone surfaces in the fitting directions. Therefore, the change in the distance from the fixed shaft 6 due to the forward and backward movement of the plunger 7 can be reduced, and the control of the attractive force of the plunger 7 by the magnetic force can be facilitated.

  FIG. 3 shows an example of a hydraulic circuit using the non-leak shockless electromagnetic proportional control valve of this embodiment as solenoid valves SV1 to SV8. This hydraulic circuit is sucked up from a reservoir by a motor-driven pump. The hydraulic oil is regulated by a relief valve that communicates with the reservoir, and is supplied to the inlet 3 of the solenoid valves SV1, 3, 5, and 7, and the outlet 2 of the solenoid valves SV1, 3, 5, and 7, respectively. Supplying to the single-acting hydraulic cylinders A to D via the check valves CV1 to CV4 and the throttle valves TV1, 3, 5, and 7 and operating oil in the single-acting hydraulic cylinders A to D to the solenoid valves SV2, 4, 6, 8 are supplied to the inlet 3, and the outlets 2 of the solenoid valves SV 2, 4, 6, 8 are returned to the reservoir via the throttle valves TV 2, 4, 6, 8, respectively. It is intended.

  FIG. 4 shows the single-acting hydraulic cylinders A to D of the above hydraulic circuit, for example, lift-up / down of the whole chair of a dental chair, tilt-up / down of the backrest, tilt-up / down of the headrest, tilt-up of the footrest・ Examples of control of single-acting hydraulic cylinders A and B when used for down respectively. For example, when the entire chair is lifted up, pump MP is turned on for a certain period of time and SV1 is pulsed during that time. The single-acting hydraulic cylinder A is gradually opened until it is fully opened by the width modulation PWM, and the single-acting hydraulic cylinder A is extended for a certain period of time.

  As a result, the non-leak shockless electromagnetic proportional control valve of this embodiment can lift up the entire chair and maintain it in its lifted up state without causing a shock at the beginning and end of extension of the single acting hydraulic cylinder A. it can. Further, for example, in the case of lift-down of the entire chair, the pump MP is kept OFF, while the SV2 is gradually opened to the full opening by the pulse width modulation PWM, and the single-acting hydraulic cylinder A is contracted by keeping the full opening for a certain time. Thereafter, the single-acting hydraulic cylinder A is maintained in a shortened state by being gradually closed until fully closed. As a result, the non-leak shockless electromagnetic proportional control valve of this embodiment can lift down the entire chair and maintain the lifted down state without causing a shock at the beginning and end of contraction of the single acting hydraulic cylinder A. it can.

  On the other hand, for example, in the case of tilting up the back of the chair, the pump MP is turned on for a certain time, and during that time, the SV3 is gradually opened by pulse width modulation PWM until it is fully opened, and is kept fully open for a certain time. After extending B, the single-acting hydraulic cylinder B is maintained in an extended state by being gradually closed until fully closed. As a result, according to the non-leak shockless electromagnetic proportional control valve of this embodiment, the backrest of the chair is tilted up to the tilted-up state without causing a shock at the beginning and end of extension of the single-acting hydraulic cylinder B. Can be maintained. For example, in the case of tilting down the back of the chair, the pump MP is kept OFF, and during that time, the SV4 is gradually opened by the pulse width modulation PWM until it is fully opened, and the single-acting hydraulic cylinder B is kept open for a certain period of time. After the contraction, the single-acting hydraulic cylinder B is maintained in a shortened state by being gradually closed until fully closed. As a result, the non-leak shockless electromagnetic proportional control valve of this embodiment tilts the backrest of the chair and maintains the tilted-down state without causing a shock at the beginning and end of contraction of the single-acting hydraulic cylinder B. be able to.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples, and can be appropriately changed within the scope of the claims, for example, around the tip of the convex portion 7g of the plunger 7 The truncated conical sealing surface 7h formed in the above may be a part of the conical surface. Further, the truncated conical seating surface 1d formed at the inlet of the outlet 2 of the main body 1 may be formed on the flat bottom surface of the recess 1a instead of the protruding portion 1b.

  Thus, according to the non-leak shockless electromagnetic proportional control valve of the present invention, the outlet is gradually opened and closed by the change in the magnetic force of the coil and the spring, and the pressure-receiving surface on the inflow chamber side of the plunger that opposes the magnetic force of the coil when the valve is opened. Since the pressure due to the pressure difference between the bearing and the fixed shaft side pressure receiving surface is made smaller than the spring pressing force due to a slight area difference between the pressure receiving surfaces, shock relaxation performance is obtained. Variations in the relaxation performance can be prevented, and the machining accuracy of the sleeve and plunger can be lowered to reduce the machining cost. Moreover, when this control valve is closed, it becomes a non-leak state that does not cause hydraulic oil leakage. Therefore, when the proportional control of the solenoid valve and the non-leak state when the valve is closed, it is not necessary to combine it with the shut-off valve. It is possible to reduce the door.

DESCRIPTION OF SYMBOLS 1 Main body 1a Recessed part 1b Protruding part 1c Inflow chamber 1d Cone conical seat surface 2 Outlet 3 Inlet 4 Base 4a Through-hole 5 Sleeve 6 Fixed shaft 6a Base end 6b Through-hole 6c Female screw 6d Tip 6e Male screw 7 Plunger 7a Front end portion 7b Protrusion 7c Rear end portion 7d Concave portion 7e Oil passage 7f Communication passage 7g Protrusion portion 7h Cone conical sealing surface 8 Spring 9 Plunger assembly 10 Flux plate 11 Coil 12 Bobbin 13 Housing 13a, 13b End plate 13c, 13d Through hole 14 Adjustment screw 14a Male screw 15 Spacer 16 Coil assembly 18 Belleville spring 19 Resin 20 Nut

Claims (4)

A body having an outlet and a recess in which the inlet opens;
A lid member fixed in a liquid-tight manner in the recess and defining an inflow chamber in the recess;
A sleeve whose one end is liquid-tightly fixed to the through hole of the lid member;
A fixed shaft liquid-tightly fixed to the other end of the sleeve;
A plunger slidably inserted into the sleeve;
A spring that is interposed between the plunger and the fixed shaft and constantly biases the plunger toward the inflow chamber;
A coil fitted around the sleeve and the fixed shaft;
A flux plate interposed between the lid member and the coil to direct the magnetic flux of the coil to the plunger;
A solenoid valve comprising:
A convex portion having a truncated conical sealing surface formed on an end surface of the plunger facing the inflow chamber;
A frustoconical seating surface formed at the inlet of the outlet of the inflow chamber, the frustoconical sealing surface separably and separably fitted to the frustoconical sealing surface;
With
When the truncated conical sealing surface and the truncated conical seating surface are fitted, the base of the truncated conical sealing surface is exposed from the truncated conical seating surface to the inflow chamber. Non-leak shockless electromagnetic proportional control valve.   2. The non-leak shockless electromagnetic proportional control according to claim 1, wherein the plunger is formed with an oil passage that communicates the clearance between the plunger and the fixed shaft and the inflow chamber. valve.   The non-leak shockless electromagnetic proportional control valve according to claim 1 or 2, wherein an adjustment screw for adjusting a preload of the spring is inserted in a liquid-tight manner and screwed to the fixed shaft. .   The end portions of the plunger and the fixed shaft facing each other are each formed with a truncated conical surface in a direction in which they are fitted to each other. Non-leak shockless electromagnetic proportional control valve.

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