JPH0481665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to improvements in movable mechanisms for opening and closing passages in various valves.

(Prior art) A valve is a general term for equipment with a movable mechanism that can open and close a passage to pass, stop, or control fluid, and in particular to change the shape of flow or control pressure or flow rate. Functionally, control valves are broadly classified into directional control valves, pressure control valves, and flow control valves.

Conventionally, a proportional solenoid system has been widely used as a mechanism for moving a valve body. As an example, the third
In the pressure control valve shown in the figure, the valve seat 3 is located in the valve chamber 2.
A passage 5 on the inlet port 4 side and a passage 7 on the outlet port 6 side are communicated via the valve seat 3 and the valve chamber 2. A movable element 25 is movably fitted into the valve chamber 2, and a solenoid 26 is disposed around the outer periphery of the movable element 25. A valve body 27 is attached to the valve body holding portion 25a of the mover 25 via a compression coil spring 28, and this valve body 27 is attached to the valve seat 3.
It is press-fitted so that it can be opened and closed. When a current is applied to the solenoid 26, the movable element 25 moves and the compression coil spring 28 is compressed, and the valve seat 3
The pressing force of the valve body 27 against the valve body 27 increases. The solenoid thrust changes proportionally according to this current value.
When the solenoid thrust and the compression coil spring 28 are balanced, the movable element 25 stops, the amount of deflection of the compression coil spring 28 is determined, and the pressing force of the valve body 27 against the valve seat 3 is also determined. The pressure on the inlet port 4 side increases and the force acting on the valve body 27 is applied to the compression coil spring 2.
When the elastic force of 8 is overcome, the valve body 27 opens the valve seat 3, the inlet port 4 side and the outlet port 6 side communicate with each other, and the pressure on the inlet port 4 side decreases. Therefore, excessive pressure increase on the inlet port 4 side is prevented. Valve body 27
The valve element 27 closes the valve seat 3 when the force acting thereon and the elastic force of the compression coil spring 28 are balanced. This operation is repeated and the pressure on the inlet port 4 side becomes approximately constant. In this way, the set pressure on the inlet port 4 side can be adjusted by changing the current value of the solenoid 26.

(Problems to be Solved by the Invention) However, in this proportional solenoid system, (a) the solenoid thrust is not very large due to the structural reasons for obtaining a thrust proportional to the current, and there is a demagnetization delay due to the solenoid's inductance, etc. Therefore, the switching of the valve body becomes slow and the response is poor (b)
Since the thrust characteristics of the solenoid are easily changed by thermal effects, variations occur in the set pressure. (c) The suction action of the solenoid acts not only on the mover but also on the body, causing hysteresis loss and reducing the solenoid thrust. (d) This will cause a delay in the movement of the mover.
Proportional solenoids have their own drawbacks, such as the need for special processing of the magnetic circuit.

Therefore, the present invention does not employ the proportional solenoid system which has such various drawbacks, but instead employs a novel piezoelectric element system.

Structure of the Invention (Means for Solving Problems) That is, the present invention provides a valve seat in the valve chamber in the body, and connects the passage on the inlet port side and the passage on the outlet port side through the valve seat and the valve chamber. In the valve, the valve chamber is provided with a valve body that can open and close with respect to the valve seat, and the valve chamber is provided with a piezoelectric element laminate for controlling the valve body, and the valve body is provided with a piezoelectric element laminate for controlling the valve body. a movable body that can expand and contract in the direction of opening and closing of the valve body based on voltage application and that can move within the valve chamber in the direction of expansion and contraction; a valve body that is pressed against the valve seat by a spring attached to the movable body; The piezoelectric element laminate for clamping is attached to the valve body so that the direction of expansion and contraction is different from that of the piezoelectric element laminate for controlling the valve body. A positioning device that is movable within the valve chamber together with the movable body and can be fixed to the inner surface of the valve chamber under pressure when extended; and a partition member that is in sliding contact with the inner surface of the valve chamber and is movable within the valve chamber together with the movable body or the positioning device. , a valve body housing chamber corresponding to the valve seat and a back pressure chamber on the opposite side are formed in the valve chamber by the partitioning member, and the back pressure chamber and the passage on the inlet port side are communicated by a pilot passage. .

(Function) When there is no voltage command for the piezoelectric element stack for controlling the valve body and for clamping, the movable body, the positioning device, and the partitioning member can move within the valve chamber, and the pressure oil supplied from the inlet port is It flows between the valve seat and the valve body to the outlet port.

First, when a voltage is applied to the piezoelectric element stack for clamping, the positioning device is fixed to the inner surface of the valve chamber based on the expansion of the piezoelectric element stack. Next, when a voltage is applied to the piezoelectric element laminate for controlling the valve body, this piezoelectric element laminate expands by a dimension corresponding to the applied voltage, and the elastic force of the spring changes depending on this expansion dimension, thereby increasing the pressing force of the valve body against the valve seat. is decided.

When the voltage applied to the piezoelectric element laminate for clamping is cut off for a short time, the partition member is pressed by the pressure oil flowing into the back pressure chamber from the inlet port side through the pilot passage, so that it is in a contracted state with the movable body. The positioning device and the partitioning member move toward the valve seat, and the pressure of the valve body against the valve seat increases.

After a short time, when voltage is applied again to the piezoelectric element stack for clamping, the positioning device is fixed to the inner surface of the valve chamber under pressure at the position after the movement based on the expansion of the piezoelectric element stack. Therefore, it is possible to maintain the pressure on the inlet port side at an arbitrary set value by changing the voltage applied to the valve body control piezoelectric element stack and adjusting the on/off of the applied voltage to the clamping piezoelectric element stack.

(Example) First, a first example in which the present invention is embodied in a pressure control valve will be described with reference to FIG.

A valve chamber 2 is provided within the body 1, and a valve seat 3 is formed on the left side thereof. An inlet port 4 and an outlet port 6 are provided on the left side of the body 1, and a passage 5 on the inlet port 4 side and a passage 7 on the outlet port 6 side are communicated via the valve seat 3 and the valve chamber 2.

Inside the valve chamber 2 is a piezoelectric element laminate 1 for controlling the valve body.
A movable body 9 consisting of 0 is disposed. The piezoelectric element laminate 10 for valve body control is made by laminating piezoelectric elements with a thickness of about 1 mm so that their expansion and contraction directions are the same, and the expansion and contraction direction based on voltage application is the opening/closing direction of the valve body 15 with respect to the valve seat 3. is made the same as Therefore, the movable body 9 can be expanded and contracted by the piezoelectric element laminate 10 for controlling the valve body, and can move within the valve chamber 2 in the direction of expansion and contraction.

A clamping piezoelectric element laminate 18 constituting the positioning device 8 is attached to the base end (right end in FIG. 1) of the movable body 9. This clamping piezoelectric element laminate 18 is arranged so that the direction of expansion and contraction based on voltage application is perpendicular to the expansion and contraction direction of the valve body control piezoelectric element laminate 10. Therefore, the positioning device 8 is movable within the valve chamber 2 together with the movable body 9 when the piezoelectric element laminate 18 for clamping is contracted, but is pressed and fixed to the inner surface of the valve chamber 2 when the piezoelectric element laminate 18 is expanded. It is becoming more and more common.

The movable body 9 and the positioning device 8 are integrally sandwiched between a pair of left and right guides 11 and 12 that constitute a partitioning member. Both guides 1
1 and 12 are in sliding contact with the inner peripheral surface of the valve chamber 2 and are movable in the direction of expansion and contraction of the piezoelectric element laminate 10 for controlling the valve body. An O-ring 13 is fitted into the left guide 11 corresponding to the valve seat 3, and a valve body housing chamber 2a is provided between the guide 11 and the valve seat 3. This guide 11 has a protrusion 14 extending toward the valve seat 3.
A protrusion 15a is provided on the valve body 15 corresponding to the protrusion 14. And valve body 1
5 and the left guide 11 of the movable body 9 is a compression coil spring 19 for the valve body inserted through both the protrusions 14 and 15a.
is biased towards the valve seat 3. In addition, the valve body housing chamber 2a has an inner surface and a left side guide 1.
1, a compression coil spring 20 for returning the movable body is interposed. On the other hand, the right guide 12
An O-ring 21 is fitted into the valve body, and a back pressure chamber 2b is provided on the opposite side of the valve body housing chamber 2a. This back pressure chamber 2b and the passage 5 on the inlet port 4 side are communicated by a pilot passage 22, and a throttle 23 is provided in the passage 5 on the inlet port 4 side between the pilot passage 22 and the inlet port 4 side. There is. An adjustment screw 16 is screwed onto the right side of the body 1 in correspondence with the right guide 12, and its inner end can come into contact with this guide 12.

This adjusting screw 16 is arranged such that the valve body 15 is fixed to the piezoelectric element laminate 1 when the piezoelectric element laminate 18 for clamping is contracted.
The movement of the movable body 9 to the right is restricted so that when the valve seat 3 moves in the direction of closing due to the expansion and contraction of 0 (in the direction of arrow A), the movable body 9 receives the reaction force. On the other hand, when the piezoelectric element laminate 18 for clamping is extended, the positioning device 8 is fixed to the inner surface of the valve chamber 2 under pressure. The reaction force of the pressing force against the valve seat 3 is received by the positioning device 8.

Each piezoelectric element of both the piezoelectric element laminates 10 and 18 for controlling the valve body and for clamping is connected to a pressure setting device 17. This pressure setting device 17 is a pressure sensor (not shown) that detects the pressure on the inlet port 4 side.
A predetermined voltage command is output to the piezoelectric element based on the input from the piezoelectric element. Note that it is also possible to use a part of the piezoelectric element laminate 10 for valve body control as a pressure sensor in place of the pressure sensor.

Now, when there is no voltage command for the piezoelectric element stacks 10 and 18 for controlling the valve body and for clamping, the movable body 9 and the positioning device 8 are movable within the valve chamber 2, and the valve body 15 is moved against the valve seat 3. There is no pressing force, and the valve seat 3 is separated from the valve seat 3, or is in a state where it can be separated. Pressure oil supplied from the inlet port 4 passes between the valve seat 3 and the valve body 15 and flows to the outlet port 6.

From this state, first operate the adjustment screw 16 to determine the movement restriction position of the movable body 9, and then apply a voltage to the clamping piezoelectric element laminate 18 using the pressure setting device 17, and the clamping piezoelectric element laminate 18 will expand. The positioning device 8 is fixed to the inner surface of the valve chamber 2 under pressure. Next, when a voltage is applied to the valve body control piezoelectric element stack 10 by the pressure setting device 17, the valve body control piezoelectric element stack 10 is expanded in the direction of arrow A by a dimension corresponding to the applied voltage. At this time, since the movable body 9 is positioned by the positioning device 8, the movable body 9 moves the valve seat 3 around this position.
Extended to the side. Due to this expansion, the valve body compression coil spring 19 is compressed, and the valve body 15 is pressed against the valve seat 3. When the valve seat 3 is closed by the valve body 15, the flow from the inlet port 4 side to the outlet port 6 side is blocked, and the pressure on the inlet port 4 side increases.

In this state, when the voltage applied to the piezoelectric element laminate 18 for clamping is cut off for a short time, the press-fixed state of the positioning device 8 to the inner surface of the valve chamber 2 is released.
Then, the pilot passage 22 is opened from the inlet port 4 side.
Pressure oil flowing into the back pressure chamber 2b through the back pressure chamber 2b acts on the right guide 12. As a result, the movable body 9, the positioning device 8, and both guides 11, 12 move toward the valve seat 3 against the biasing force of the movable body return compression coil spring 20, and the pressure force of the valve body 15 against the valve seat 3 increases. When a voltage is applied to the piezoelectric element stack 18 for clamping again after a short time, the piezoelectric element stack 18 for clamping expands, and the positioning device 8 is fixed to the inner surface of the valve chamber 2 under pressure due to this expansion. Positioned at a moving position.

The pressure on the inlet port 4 side is detected by a pressure sensor, and this detected pressure is input to the pressure setting device 17. When this detected pressure becomes higher than the set value of the pressure on the inlet port 4 side, the force acting on the valve body 15 overcomes the elastic force of the valve body compression coil spring 19, and the valve body 1
5 opens the valve seat 3, the inlet port 4 side and the outlet port 6 side communicate with each other, and the pressure on the inlet port 4 side decreases. Therefore, excessive pressure rise on the inlet port 4 side can be prevented, and the pressure on the inlet port 4 side can be maintained at an arbitrary set value.

When the voltage applied to the valve body control piezoelectric element stack 10 is changed, the valve body control piezoelectric element stack 10 expands and contracts in accordance with the applied voltage, and the amount of deflection of the valve body compression coil spring 19 changes. The pressing force of the valve body 15 against the valve seat 3 is determined according to this amount of deflection, and the set pressure on the inlet port 4 side can be changed.

When the cut-off time of the piezoelectric element laminate 18 for clamping is changed, the positioning device 8
The fixed position of changes. Therefore, in addition to adjusting the pressure contact force of the valve body 15 by the valve body control piezoelectric element stack 10, the pressure contact force of the valve body 15 can also be adjusted by changing the cut-off time of the clamping piezoelectric element stack 18. I can do it.

Piezoelectric element laminate 1 for valve body control and clamping
When the applied voltages 0 and 18 are cut off, the piezoelectric element laminate 10 for controlling the valve body contracts in the direction opposite to the arrow A, the valve seat 3 opens, and the pressure oil on the inlet port 4 side flows to the outlet port 6 side. The passage 5 on this inlet port 4 side has a restriction 2.
3, the pressure between the throttle 23 and the valve seat 3 becomes low, and the pressure oil in the back pressure chamber 2b flows into the pilot passage 2.
2 and flows back into the passage 5 on the inlet port 4 side.
As a result, the movable body 9, the positioning device 8, and both guides 11, 12 are returned to the right by the movable body return compression coil spring 20 and stop when they come into contact with the adjustment screw 16.

In the second embodiment shown in FIG. 2, a tension coil spring 24 for returning the movable body is provided in the back pressure chamber 2b in place of the compression coil spring 20 for returning the movable body in the first embodiment, and both ends of the tension coil spring 24 are connected to the right guide 12. and is fixed to the inner surface of the back pressure chamber 2b, and the operation of this second embodiment is the same as that of the first embodiment.

Effects of the Invention As detailed above, according to the present invention, in addition to adjusting the pressure contact force of the valve body by the piezoelectric element laminate for controlling the valve body provided in the movable body, the piezoelectric element laminate for clamping provided in the positioning device In addition, since the pressure contact force of the valve body can be adjusted by the pilot passage, fine pressure control over a wide range is possible, and excellent controllability of the valve is achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a pressure control valve according to a first embodiment, FIG. 2 is a sectional view showing a pressure control valve according to a second embodiment, and FIG. 3 is a sectional view showing a conventional pressure control valve. be. In the figure, 2 is a valve chamber, 2a is a valve body storage chamber, 2b is a back pressure chamber, 3 is a valve seat, 4 is an inlet port, 5 is an inlet port side passage, 6 is an outlet port, 8 is a positioning device,
9 is a movable body, 10 is a piezoelectric element laminate for controlling a valve body,
11 and 12 are left and right guides as partition members; 15
is a valve body, 18 is a piezoelectric element laminate for clamping, 19
2 is a compression coil spring for the valve body, 22 is a pilot passage, and 23 is a throttle.

Claims (1)

[Claims] 1. A valve seat is provided in the valve chamber in the body, and a passage on the inlet port side and a passage on the outlet port side are communicated via the valve seat and the valve chamber. On the other hand, in a valve provided with a valve body that can be opened and closed, a piezoelectric element stack 10 for controlling the valve body is provided in the valve chamber 2, and the valve body A movable body 9 that can expand and contract in the direction of the opening and closing operation of 15 and can move within the valve chamber 2 in the expansion and contraction direction.
And, the valve seat 3 is moved by the spring 19 attached to this movable body 9.
A valve body 15 is pressed against the movable body 9, and a piezoelectric element laminate 10 for controlling the valve body is attached to the movable body 9.
The clamping piezoelectric element laminate 18 is attached so that the direction of expansion and contraction is different from that of the clamping piezoelectric element laminate 18, which expands and contracts based on voltage application to the clamping piezoelectric element laminate 18, and when contracted, the valve chamber 2 along with the movable body 9. a positioning device 8 that is movable within the valve chamber 2 and can be fixed to the inner surface of the valve chamber 2 under pressure when extended; and a partition member that is in sliding contact with the inner surface of the valve chamber 2 and is movable within the valve chamber 2 together with the movable body 9 or the positioning device 8. 1
1 and 12, and the partition members 11 and 12 form within the valve chamber 2 a valve body storage chamber 2a corresponding to the valve seat 3 and a back pressure chamber 2b on the opposite side, and the back pressure chamber 2b and A piezoelectric element valve in which a pilot passage 22 communicates with a passage 5 on the inlet port 4 side. 2. The piezoelectric element valve according to claim 1, wherein a restriction 23 is provided in the passage 5 on the inlet port 4 side between the pilot passage 22 and the inlet port 4.