JPH066858U - Solenoid proportional pressure control valve - Google Patents

Abstract

(57) [Abstract] [Purpose] Providing a poppet-type electromagnetic proportional pressure control valve that can increase control pressure without the need to strengthen the solenoid guide tube, without reducing the valve seat diameter and without changing the flow rate. To do. [Structure] A valve seat diameter 22a is provided at the seating end of the poppet 21.
A piston portion 21b having a smaller diameter is extended and the piston portion 2
1b is slidably inserted into the through hole 22b of the valve seat 22,
Further, the tip of the piston portion 21b is a tank port T, and there is a movable iron core 2, a fixed iron core 5, and a solenoid coil 11 there.
And a push-type electromagnetic proportional solenoid including a push pin 3 that causes the suction force of the movable iron core 2 to act in the direction of separating the poppet 21, and the diameter of the piston portion 21b is increased to make the valve seat diameter 22a. The control pressure of the control port A can be increased by reducing the pressure receiving area due to the diameter difference.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 In the poppet type electromagnetic proportional pressure control valve of the present invention, the force of the electromagnetic proportional solenoid is applied from the opposite side of the direction of action of the pressure control spring that urges the pressure control poppet to move in the seating direction on the valve seat, and the input current is applied. It relates to the structure of an electromagnetic proportional pressure control valve in which the maximum control pressure is reached when is zero, and the control pressure decreases as the input current increases.

[0002]

[Prior art]

 Conventionally, a general electromagnetic proportional pressure control valve has a control pressure that increases proportionally to the input current value, and the pressure becomes the lowest when the input current value is zero. This type of electromagnetic proportional pressure control valve is used for a hydraulic chuck of a lathe spindle, etc., and when pressure control is performed to obtain a grasping force according to the workpiece, the amplifier that performs current control fails, or the solenoid coil is disconnected. If the electric circuit is broken or has poor contact, the gripping force of the hydraulic chuck will decrease, and there is a risk that the workpiece rotating at high speed will be scattered.

Therefore, an electromagnetic proportional pressure control valve has been developed in which, when the control pressure decreases as the input current value increases and the current becomes zero, the control pressure is maximized by the pressure adjusting spring. It was Examples thereof include Utility Model Application Publication No. 2-35099 “Electromagnetic proportional pressure control valve” and Utility Model Application Publication No. 3-614 “Electromagnetically operated pressure control valve”.

For example, referring to FIG. 2, the former Japanese Utility Model Publication No. 2-35099 will be described with reference to FIG. 2. Reference numeral 41 is a valve case, and a valve hole 42 and a pump port 43 and a tank connected to the valve hole 42 at inner ends thereof, respectively. Ports 44 and are drilled. A valve seat 45 is formed on the inner peripheral surface of the valve hole 42 in the middle of the inner opening of each of the ports 43 and 44, and the pilot valve 46 slides from the opening of the tank port 44 with respect to the valve seat 45. Put it on freely and let it sit. The pilot valve 46 is provided with a rod portion 46a slidably supported by a guide hole of an adjusting screw 48 screwed axially freely from the tank port 44 side of the valve hole 42.

Reference numeral 49 is a spring for hydraulic control that is crimped between the adjusting screw 48 and the pilot valve 46 to urge the pilot valve 46 in the seating direction with respect to the valve seat 45, and 50 is located on the pump port 43 side of the valve case 41. A movable iron core 52, which is a continuous iron case, in which a fixed iron core 51 and a push pin 56 slidably inserted in a pin insertion hole bored in the axial direction thereof are connected in series, and a solenoid. The coil 57 and the coil 57 are arranged concentrically. Reference numeral 59 denotes a pilot spring which is crimped between the push pin 56 and the pilot valve 46 and urges the pilot valve 46 in the seating direction against the urging force of the hydraulic control spring 49.

When the solenoid coil 57 of the electromagnetic proportional pressure control valve configured as described above is energized, a magnetic force is induced in the fixed iron core 51 to attract the movable iron core 52 toward the fixed iron core 51 and push the pin. 56 is projected toward the pilot spring 59 to actuate the pilot valve 46 in the direction of separation via the pilot spring 59. When the acting force of the push pin 56 acting via the pilot spring 59 and the pressure of the pressure oil from the pump port 43 overcome the spring force of the hydraulic control spring 49, the pilot valve 46 performs a relief operation, and the spring. The hydraulic pressure corresponding to the force is established in the pump port 43. Therefore, the pressure at the pump port 43 is controlled to decrease in proportion to the current flowing through the solenoid coil 57. Further, when the electric current is cut off due to a failure of the electric system, the push pin 56 is retracted to the final retracted position shown in the figure, so that the spring force of the pilot spring 59 is weakened to the maximum and the hydraulic control spring 49 of the hydraulic control spring 49 is reduced. Since the spring force is practically maximized, the maximum hydraulic pressure is established in the pump port 43.

Further, for example, referring to FIG. 3, an example of the invention of Japanese Utility Model Publication No. 3-614 will be described. In FIG. A hole 64 is provided so that the small-diameter valve hole 64 communicates with a control passage 65 to the actuator, and a supply passage 66 from a hydraulic pump that is always kept at a higher pressure than the control passage 65 communicates with the throttle 67. Further, the large-diameter valve hole 62 communicates with a discharge passage 68 to the storage tank. A valve element 69 is connected to one end side of the movable iron core 74 so as to be seated on the valve seat 63. The pressure of the control passage 65 acts on one end side from the small diameter valve hole 64 and is pushed in the separating direction. I have to. Reference numeral 70 denotes an electromagnetic device attached to the valve body 61 so as to cover the opening of the large-diameter valve hole 62. A movable iron core 74 is coaxially arranged with the valve seat 63 on one end side in a case 71 which serves as a magnetic path. A yoke 75 that is movably inserted and supported is provided, and a fixed iron core 76 is provided at the other end side, and a coil 77 is provided between the fixed iron core 76 and the yoke 75, and when the coil 77 is energized, the movable iron core 76 is provided. The movable iron core 74 is attracted to the fixed iron core 76 and acts on the movable iron core 74 in the separating direction of the valve body 69. The acting force generated on the movable iron core 74 is the current supplied to the coil 77. I am trying to increase according to the increase of. Reference numeral 78 is a pressure adjusting spring that presses the movable iron core 74 in the seating direction of the valve body 69, and extends over the spring receiver 79 screwed to the fixed iron core 76 so as to be adjustable forward and backward and the other end side of the movable iron core 74. It is installed.

With the above configuration, when the coil 77 is not energized, the valve body 69 is seated on the valve seat 63 by the spring force of the pressure adjusting spring 78, and the pressure in the control passage 65 rises to adjust. When the spring force of the pressure spring 78 becomes higher than that of the pressure spring 78, the valve body 69 separates and the liquid flows out to the discharge passage 68 to keep the pressure in the control passage 65 constant. When the coil 77 is energized, an acting force is generated in the movable iron core 74 in the direction in which the valve body 69 is separated according to the current, and the spring force of the acting force adjusting spring 18 is weakened. The pressure in the control passage 65 can be adjusted depending on the size of the. Even in the present invention, the pressure in the control passage 65 is highest when the power is not supplied.

[0009]

[Problems to be solved by the device]

 However, in the example of the solenoid proportional valve shown in FIG. 2, the pressure oil for control is introduced into the solenoid guide tube 50a containing the fixed iron core 51 and the movable iron core 52. In order to increase the pressure, it is necessary to increase the strength or the thickness of the thin solenoid guide tube 50a. If the wall thickness is increased, the magnetic efficiency of the solenoid will deteriorate and the attractive force will decrease.

In addition, when trying to control pressure oil of higher pressure, both of the above-mentioned conventional techniques (FIGS. 2 and 3) deal with an increase in load on the pressure adjusting spring. The spring force must be increased, in which case the maximum suction force of the solenoid required to counter the spring force of the pressure adjusting spring must also be increased. Therefore, the required energizing current increases and the control amplifier also needs to have a high output.

Further, as another means, when the pressure oil to be controlled is increased without changing the suction force of the solenoid, the valve seat diameter may be reduced, but in this case, the control is possible. There was a problem that the effective flow rate was reduced.

In addition, the conventional solenoid proportional valve shown in FIG. 3 uses a pull solenoid instead of the general push proportional solenoid used in solenoid proportional valves widely used in general industrial machines. Since it is used, there was a problem that the production efficiency was poor and the manufacturing cost was high.

The present invention has been made in view of the above-mentioned problems of the conventional art, and by making the inflow pressure oil not flow into the solenoid guide tube of the comparative solenoid, the thickness of the solenoid guide tube is increased. First, an object of the present invention is to provide an electromagnetic proportional pressure control valve capable of increasing the pressure of control pressure oil with a simple structure by using a push type proportional solenoid without changing the valve seat diameter.

[0014]

[Means for Solving the Problems]

 The present invention is directed to a piston part having a diameter smaller than the seat diameter of the valve seat, which extends coaxially with the seating end of the pressure control valve body, and a penetrating part which slidably fits the seat part and the piston part and projects to the opposite side. A valve seat having a hole, and a pressure adjustment spring that acts in the seating direction of the valve body against the hydraulic pressure applied to the difference between the piston diameter of the valve body and the seating diameter of the valve seat, An electromagnetic proportional solenoid arranged so as to counteract the acting force of the pressure adjusting spring and act on the tip of the piston portion via a bias spring, and the control pressure can be increased by increasing the diameter of the piston portion. The above problems have been solved by providing the electromagnetic proportional pressure control valve described above.

That is, according to the present invention, a through hole is formed from the seating portion of the valve seat to the opposite side in the seating direction, and the valve body is slidably fitted in the through hole coaxially with the seating direction tip end. A piston with a diameter smaller than the valve seat diameter protruding to the opposite side of the installation hole is integrally extended, and the pressure receiving area is formed by the diameter difference between the piston diameter and the valve seat diameter. In addition, a pressure port that flows in to separate the valve body from the direction intersecting the axis is provided, and a pressure adjustment spring that biases the valve body in the seating direction is provided. Provide an electromagnetic proportional pressure control valve that adjusts the control pressure by operating an electromagnetic proportional solenoid from the side to the tip of the piston via a bias spring to oppose the spring force of the pressure adjusting spring. Is.

[0016]

[Action]

 Since the present invention is configured as described above, only the diameter difference portion and the inflow port are controlled to achieve high pressure, and the inside of the proportional solenoid guide tube is the tank port pressure and is not related to the control pressure. The magnetic efficiency can be increased by using the guide tube of. Also, the pressure receiving area can be reduced by bringing the piston diameter at the tip of the valve closer to the valve seat diameter without changing the valve seat diameter, and with the same pressure force adjustment spring load and suction force of the proportional solenoid. Since the pressure can be increased and the valve seat diameter does not have to be made small, it has the advantage that the controllable flow rate does not decrease. Further, because of its structure, a push type proportional solenoid which is widely used can be used, so that the manufacturing cost can be reduced.

[0017]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is an explanatory view of an electromagnetic proportional pressure control valve according to an embodiment of the present invention, in which 1 is a coil lock nut for mounting and fixing a solenoid coil 11 on an electromagnetic proportional solenoid, and 5 and 2 are coaxial with the solenoid in the solenoid. A fixed iron core 5 that is mounted and that generates a magnetic force by energizing the solenoid coil 11 and a movable iron core 2 that operates so as to be attracted to it. Reference numeral 3 is fixed to the movable iron core 2 by a set screw 17 and is movable. A push pin 4 that acts to press the bias spring 25 when the iron core 2 is attracted to the fixed iron core 5, 4 is a solenoid guide tube that guides the movement of the movable iron core 2, and 6 is a push pin 3 and one end thereof. Is a pressure adjusting screw capable of adjusting the position of the push pin 3 by being rotated so that the push pin 3 can be brought back.

Reference numeral 21 denotes a seating direction distal end which integrally extends a piston portion 21 b which projects to the opposite side of the valve seat 22 and extends to a spring receiver for receiving the bias spring 25, and receives the pressure of the control pressure oil from the pump port P. 22 has a through hole 22b into which the piston portion 21b is slidably inserted, and a valve seat which works together with the poppet 21 to control the control hydraulic pressure. 23 denotes the poppet 21. It is a pressure adjusting spring that is urged against the valve seat 22 in the seating direction to seat it, and acts so as to counteract the hydraulic pressure applied to the area of difference in diameter with the piston portion 21b having a smaller diameter than the valve seat diameter 22a.

A is a pressure control port in which pressure oil flows in from a pump port P provided in an outer peripheral direction intersecting the axis of the valve seat 22 and the hydraulic pressure acts in a direction to separate the poppet, and B is a tank port T. It is an outflow port that communicates. With this configuration, the inside of the solenoid tube 4 having the bias spring chamber C, the movable iron core 2 and the fixed iron core 5 is communicated with the tank port T, and is maintained at a low pressure.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described. When the solenoid is not energized, it flows in from the pump port P and acts on the poppet 21 in the seating direction by the pressure oil. When the hydraulic pressure becomes equal to or higher than the pressure that opposes the load of the pressure adjusting spring 23, the poppet 21 is separated from the valve seat 22, the hydraulic oil flows out to the outflow port B, and returns to the tank port T. As a result, the hydraulic pressures of the pump port P and the pressure control port A are kept constant.

On the other hand, since the push pin 3 of the solenoid is in contact with the side of the bias spring 25 opposite to the piston portion 21b via the spring receiver 24, when a predetermined amount of current is applied to the solenoid coil 11, the movable iron core is moved. 2 is attracted to the fixed iron core 5, and the push pin 3 fixed to the movable iron core 2 disengages the poppet 21 via the spring receiver 24, the bias spring 25, the spring receiver 26, and the piston portion 21b. Act on. Therefore, the adjusting pressure for pressing the poppet 21 in the seating direction is the spring force of the pressure adjusting spring 23 minus the acting force generated in the movable iron core 2, and the pressure obtained at the pressure control port A is the solenoid coil. It will be lower than when not energized.

When the value of the electric current applied to the solenoid coil 11 increases, the acting force generated in the movable iron core 2 increases accordingly, so that the poppet determined by the difference from the spring force of the pressure adjusting spring 23 whose strength does not change. The adjusting pressure of 21 becomes relatively small. In other words, the pressure obtained from the pressure regulation decreases as the current value increases, and conversely becomes maximum when the current is not applied.

The push pin 3 can be brought into contact with one end of the pressure adjusting screw 6 screwed to the coil lock nut 1. The pressure adjusting screw 6 is rotated and screwed into the push pin 3 and the spring. The bias spring 25 is pre-bent through the receiver 24. Since the spring force acts in the direction of separating the poppet 21, the setting of the adjustment pressure when the solenoid coil 11 is not energized can be changed.

[0024]

[Effect of device]

 As described above, according to the present invention, a piston portion having a diameter smaller than the valve seat diameter is extended at the seating end of the poppet, and the piston portion is slidably inserted into the through hole of the valve seat. By making the tip of the piston part a tank port, a push-type electromagnetic proportional solenoid can be attached to it, and since the pump proportional pressure is not applied to the electromagnetic proportional solenoid, increase the pressure of the pump port. Also, there is no need to increase the strength of the solenoid guide tube.

Further, the piston portion having a diameter smaller than the valve seat diameter is provided at the tip of the poppet, and the control oil pressure is applied to the diameter difference area. Therefore, when the control oil pressure of the pump port is increased, By increasing the diameter of the section, the diameter difference from the valve seat diameter can be reduced, and the pressure-receiving area of the control hydraulic pressure can be reduced, so that the valve seat diameter can be reduced and the controllable flow rate can be reduced. It is possible to increase the control oil pressure.

[Brief description of drawings]

FIG. 1 is an explanatory view of an electromagnetic proportional pressure control valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional electromagnetic proportional pressure control valve.

FIG. 3 is a cross-sectional view of another conventional electromagnetically operated pressure control valve.

[Explanation of symbols]

 1: Coil lock nut 2: Movable iron core 3: Push pin 4: Solenoid guide tube 5: Fixed iron core 6: Pressure adjusting screw 11: Solenoid coil 17: Set screw 21: Poppet 21b: Piston part 22: Valve seat 22a: Valve seat diameter 22b: Through hole 23: Pressure adjusting spring 24, 26: Spring receiver 25: Bias spring A: Pressure control port B: Outflow port C: Bias spring chamber

Claims (1)

[Scope of utility model registration request] 1. A piston portion having a diameter smaller than a valve seat seating diameter extending coaxially with the seating direction tip of a pressure control valve body, and a penetrating body in which the seating portion and the piston part are slidably inserted and protrude to the opposite side. A valve seat having a hole, a pressure adjusting spring that acts in the seating direction of the valve body against the hydraulic pressure applied to the diameter difference between the piston portion diameter of the valve body and the seating diameter of the valve seat, An electromagnetic proportional solenoid arranged to act on the tip of the piston portion via a bias spring against the acting force of the pressure adjusting spring, and to increase the control pressure by increasing the diameter of the piston portion. Electromagnetic proportional pressure control valve.