JPH0319654Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a directional control valve, and more specifically, to a directional control valve in which a valve member is opened and closed by an electrostrictive element. It is.

[Prior Art] Directional switching valves that utilize the property of a laminated electrostrictive element to expand and contract when energized to open and close a valve seat with a valve member provided on the electrostrictive element include, for example,
This is known from Japanese Patent Application Laid-open No. 111226/1983.

However, such a laminated electrostrictive element has a characteristic that the acting force associated with expansion and contraction is large but the stroke is small, and therefore it is difficult to apply it to switching valves that require a large stroke. .

In order to solve this problem, the stroke of the electrostrictive element was amplified using a lever.
This is proposed by Publication No. 9075. However, when the stroke is amplified by a lever, the amount of displacement of the point of action changes greatly due to slight variations in the positions of the fulcrum, force point, and point of action due to manufacturing errors, etc. If the amount of displacement of the valve member is large, the acting force due to the expansion of the electrostrictive element is extremely large, and the valve member is pressed against the valve seat with excessive force, resulting in wear and tear. If the amount of displacement of the valve member becomes large and the amount of displacement of the valve member is small, a new problem arises in that the sealing force of the valve seat is insufficient and fluid tends to leak.

[Problem to be solved by the invention] The problem to be solved by the invention is to amplify the stroke of a laminated electrostrictive element using a lever, and to find a direction in which the valve seat sealing force can be easily adjusted by the valve member. The purpose of the present invention is to provide a switching valve.

[Means for Solving the Problems] In order to solve the above problems, the directional control valve of the present invention includes a valve seat, a laminated electrostrictive element that expands and contracts when a voltage is applied and released, and an intermediate position between these elements. a pedestal, an elastic lever swingably supported by the pedestal, and a valve member for opening and closing the valve seat attached to the tip of the elastic lever, and the electrostrictive element is attached to the base end of the elastic lever. the lever, the distance between the pedestal and the valve member of the lever is larger than the distance between the pedestal and the electrostrictive element connecting portion, and the valve seat and the pedestal are arranged in the swinging direction of the elastic lever. It is characterized by being able to move forward and backward.

[Operation] When a predetermined voltage is applied to the electrostrictive element, the electrostrictive element expands and presses the base end of the lever to rotate the lever. The members switch to open or close the valve seat.

At this time, since the distance between the fulcrum of the lever and the valve member is larger than the distance between the fulcrum and the electrostrictive element connection part, the extension stroke of the electrostrictive element is amplified, and the valve member is larger than the electrostrictive element. Move with strokes.

In this case, the elasticity of the lever absorbs and reduces the acting force of the electrostrictive element, and by moving the valve seat and pedestal forward and backward with respect to the swinging direction of the lever, the force of the valve member abutting against the valve seat is reduced. The contact force can be adjusted very easily to obtain the desired contact force.

When the application of voltage to the electrostrictive element is removed, the electrostrictive element returns to its expanded and contracted state, and the valve member returns to its initial state.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 illustrates the case where the present invention is applied to a 3-port valve, in which 10 is the valve body;
1 is an input port provided in the body 10; 12 is an input port provided in the body 10;
indicates the same output port, 13 indicates the same discharge port, and the valve chamber 14 through which these ports 11 to 13 communicate
Inside is a first valve seat 1 that communicates with the input port 11.
5 and a second valve seat 16 communicating with the discharge port 13 are formed to face each other, and between these valve seats 15 and 16, a valve member 17 for alternately opening and closing them is attached to the tip of an elastic lever 18. It is arranged according to the requirements.

The input port 11 and the first valve seat 15, and the discharge port 13 and the second valve seat 16 are provided on screw members 19 and 20, respectively, so that the distance between them can be adjusted.

The elastic lever 18 is made of an elastic material such as a leaf spring, and has a fulcrum 2 at an intermediate position.
2, whose fulcrum 22 is swingably supported by a pedestal 24 on an adjustment screw 23, and a push rod 26 integrated with an electrostrictive element 25 abuts the base end of the elastic lever 18. A return spring 27 is disposed at a position of the elastic lever 18 close to the valve member 17 and urges the elastic lever 18 in a direction in which the valve member 17 closes the first valve seat 15. The fulcrum 22 of the elastic lever 18 is such that the distance a between the fulcrum 22 and the valve member 17 is the same as that between the fulcrum 22 and the push rod 26.
It is formed at a position that is larger than the distance b between the connecting portion and the connecting portion.

The electrostrictive element 25 is of a laminated type made by laminating a large number of plate-like materials, and expands in the axial direction when a voltage of a predetermined polarity is applied, and when a voltage of the opposite polarity is applied or a voltage is applied. When released, it returns to the contracted state. This electrostrictive element 25 is inserted into an accommodation chamber 29 separate from the valve chamber 14 in which the elastic lever 18 is disposed, and is provided with an adjusting screw 31 via a pedestal 30.
The push rod 26 is fixed to the tip of the push rod 26 in a fluid-tight manner through an O-ring 32 into the valve chamber 29.

In addition, in the figure, 33 indicates an O-ring, and 34 indicates a spring seat.

In the direction switching valve having the above configuration, when a predetermined voltage is applied to the electrostrictive element 25, the electrostrictive element 25 extends in the axial direction, and the push rod 26 at the tip presses the base end of the elastic lever 18. Therefore, the elastic lever 18 rotates around the fulcrum 22, and the valve member 17 attached to its tip switches, opening the first valve seat 15 and closing the second valve seat 16.

At this time, the distance a between the fulcrum 22 of the elastic lever 18 and the valve member 17 is
6, the extension stroke of the electrostrictive element 25 is amplified by this elastic lever 18, and the opening/closing stroke of the valve member 17 is larger than the extension stroke of the electrostrictive element 25. growing. Further, the large acting force of the electrostrictive element 25 is absorbed and alleviated by the elasticity of the elastic lever 18, and the force of the valve member 17 being pressed against the second valve seat 16 due to the movement of the second valve seat 16 and the pedestal 24 back and forth. can be adjusted, it is possible to prevent wear and tear on the valve member 17 due to excessive pressure contact and fluid leakage due to poor sealing of the valve seat 16.

When the voltage application to the electrostrictive element 25 is released, the electrostrictive element 25 returns to the contracted state, and the elastic lever 1
8 is also returned to its initial position by the biasing force of the return spring 27, so the second valve seat 16 is opened by the valve member 17 and the first valve seat 15 is closed. Also in this case, by moving the first valve seat 15 back and forth, the valve member 17 can reliably close the first valve seat 15 with an appropriate contact force.

FIG. 2 shows a sliding member 35 made of a slippery material attached to the base end of an elastic lever 34.
A fulcrum 36 is formed at the fulcrum 3, and a push rod 37 of the electrostrictive element is brought into contact with the fulcrum 36.
This is intended to prevent wear and tear at the portion 6 and the portion where the push rod 37 comes into contact, and to prevent a reduction in the transmission force.

[Effect of the invention] According to the invention having the above configuration, the displacement of the electrostrictive element is amplified by the elastic lever and transmitted to the valve member. The stroke valve member can be operated to open or close.

In addition, the elasticity of the lever can absorb and relieve the acting force of the electrostrictive element, and by moving the valve seat and pedestal back and forth, the pressure force applied to the valve seat by the valve member can be adjusted extremely easily. .

Therefore, it is possible to reliably prevent wear and tear of the valve member due to excessive pressure contact with the valve portion and leakage of fluid due to poor sealing of the valve seat.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 2 is a sectional view of a main part of another embodiment. 15...first valve seat, 16...second valve seat, 17...
... Valve member, 18 ... Elastic lever, 22 ... Fulcrum,
25...Electrostrictive element.

Claims (1)

[Claims for Utility Model Registration] A valve seat, a laminated electrostrictive element that expands and contracts when a voltage is applied and released, a pedestal located between these elements, and an elastic lever swingably supported by the pedestal. and a valve member that opens and closes the valve seat attached to the tip of the elastic lever, the electrostrictive element is connected to the base end of the elastic lever, and the distance between the base of the lever and the valve member is adjusted. , a directional control valve characterized in that the distance is greater than the distance between the pedestal and the electrostrictive element connection portion, and the valve seat and the pedestal are movable forward and backward with respect to the rocking direction of the elastic lever. .