JPH02199378A - Directional control valve - Google Patents

Abstract

PURPOSE:To miniaturize a valve, reduce the cost, and allow high-density piping by providing a solenoid driving a spool, a plunger slidably provided in the spool, and an excitation deformation member driving the plunger. CONSTITUTION:To communicate the first port (1) and a common port (3) from the all-port cutoff position, for example, an excitation deformation member 9 is excited, and a plunger 7 provided in a spool 2 is moved from the port cutoff position as a result of this deformation. To communicate the second port (2) and the common port (3), a solenoid 10 is turned on to move the spool 2, and a passage 4 to the second port (2) of the spool 2 is communicated to the common port (3). A directional control valve is obtained which can control three positions: all-port cutoff position, communicating position of the first port (1) and the common port (3), and communicating position of the second port (2) and the common port (3), with only one solenoid 10 by adding the action of the plunger 7.

Description

Detailed Description of the Invention [Industrial Application Field] This invention provides communication between a first port and a third port, and communication between a second port and a third port, even though there is only one solenoid. The present invention relates to a directional control valve that can control a total of three positions: communication between ports and isolation between both first and second ports and a third port.

[Conventional technology]

2. Description of the Related Art So-called directional control valves equipped with a solenoid are often used as valves that automatically switch or shut off passages of fluid pressure such as hydraulic pressure or pneumatic pressure. Among such directional control valves, for example, one having three ports such as a first port, a second port, and a common port (third port) is usually the one shown in Fig. 5. There is something like that. In the figure, when connecting the first port ■ and the common port ■, by turning on the solenoid M1, a valve such as a spool of the direction control valve is compressed against the elasticity of three attached springs. move it in the direction you want. Next, to cut off the communication between ports ■ and ■, use solenoid M.
, by turning off the spool, the spring S2
It returns to its original position due to its elasticity. Similarly, to establish communication between ports ■ and ■, turn on solenoid M2 and move the spool against the elasticity of spring Sl, and turn off solenoid M2 and the spool will return to its original position due to the elasticity of spring S. Return to position. In other words, the illustrated directional control valve can be controlled in three positions: when the solenoid is OFF, all ports are blocked, when the solenoid M1 is turned on, the ports ■ and ■ are communicated with each other, and when the solenoid M2 is turned on, the ports ■ and ■ are communicated with each other. This is what we do.

[Problem to be solved by the invention] However, in such a conventional directional control valve,
Since the solenoid can only control two positions by turning it ON and OFF, two solenoids are required to control three positions.

Since the solenoid has a tall shape, the valve shape becomes large, which obstructs high-density piping, and the costs of the valve itself and the fluid pressure piping increase.

The present invention has been made in view of these conventional problems, and aims to solve the above problems by using an energized deformable member in addition to one solenoid.

[Means to solve the problem]

The present invention provides a valve body having three ports, a first passage for fluid pressure provided within the valve body and communicating a first port and a third port of the valve body, and a second passage for fluid pressure. a spool having a second fluid pressure passage communicating the port and the third port independently of the first passage; and the spool is driven to alternately connect the two passages of the spool to the valve body. A directional control valve comprising a solenoid corresponding to each port, a plunger that is slidably provided in the spool and opens and closes a first passage, and an energized deformable member that performs a deforming operation when energized to drive the plunger. That is.

[Operation] Since the present invention is configured as described above, for example, the first port and the common port (third
In order to establish communication between the spool and the spool, the plunger provided in the spool may be moved from the port cutoff position by energizing the energizing deformable member and deforming the energizing deformable member. Next, in order to communicate the second port with the common port, if the spool is moved by turning on the solenoid, the path of the spool to the second port and the common port are communicated. Therefore, all ports are in the blocked position.

Even though there is only one solenoid, the communication position between the first port and the common port and the communication position between the second port and the common port is a directional control valve that can be controlled in 3 positions by adding plunger operation. be able to.

〔Example〕

The present invention will be explained below based on the drawings. 1 to 3 are diagrams for explaining an embodiment of the present invention as a directional control valve for direct gas flow.

First, to explain the configuration, a bore 1a with one end closed and the other end open is formed in the valve body 1, and a first port 2 is perpendicular to the bore 1a.

A second port (2) and a common port (third port) (3) are formed. The first port (2) and the common port (2) are arranged on the same straight line, and the second port (2) is formed perpendicularly to both of them.

A spool 2 is fitted into the bore la so that it can move forward and backward,
The spool 2 is urged toward the closed end of the bore 1 by a compression spring 12 seated on a solenoid 10 fixed to the open end of the valve body 1 and disposed within the bore la. The closed end of the bore 1a communicates with the outside air through a small hole 1c in the valve body 1 in order to prevent malfunction of the spool 2 due to airtightness.

The spool 2 is provided with a first diametrical passage 3 that communicates with the ports (1) and (2), and a first passage 3 (3) is formed in the spool 2 at a different position in the forward and backward direction of the spool 2 (independent of the passage 3). A bent second passage 4 communicating the second port (2) and the common port (2) is bored.

A tube 5 is connected to the first port (■) of the valve body 1 using a one-touch joint, while a common port (■) of the valve body 1 has a taper threaded portion 6 for connecting it to a fluid pressure device such as a cylinder. It is formed.

A cylindrical portion 2a extending in the axial direction of the spool 2 is protruded from the end of the spool 2 on the compression spring 12 side, and a bore 2b is formed in the spool 2 continuously from the inside of the cylindrical portion 2a. The bore 2b opens into the passage 3. A plunger 7 is fitted into the bore 2b from within the cylindrical portion 2a so as to be freely retractable.
When the tip of the tube protrudes into the passage 3 as shown in Fig. 1,
This passage 3 is closed.

A bias spring 8 is interposed in the cylindrical portion 2a between the plunger 7 and an inward flange formed at the open end thereof, and urges the plunger 7 in the projecting direction.

An energizing deformable member 9 is installed between the rear end of the plunger 7 and the lid 11 at the outer end of the solenoid 10. In this embodiment, the energized deformable member 9 is a shape memory alloy that recovers its reduced shape as shown in FIGS. 2 and 3 when energized and heated.

Since this energized deformable member 9 is easily deformed by external force at low temperatures (when not energized), it is suspended in a straight line by the bias spring 8 as shown in FIG. The bias spring 8 biases the plunger 7 and tensions the energized deformable member 9.

The solenoid 10 attracts the spool 2 by magnetic force against the bias of the compression spring 12 when turned on, and the passage 4 is located at a position where the second port (2) and the common port (2) communicate with each other at this time, And solenoid 10 is turned off.
Therefore, when the spool 2 returns to the position shown in FIG. 1 due to the biasing force of the compression spring 12, the passage 3 is located at a position where the first port (2) and the common port (2) communicate with each other.

Next, the operation will be explained.

First, connect the first port ■ and the common port ■,
When supplying fluid pressure to an actuator such as a cylinder (not shown) connected to the Taper screw 6, the temperature of the deformable member 9 is increased by energizing the deformable member 9.
restores the memorized shape with a force greater than the elasticity of the bias spring 8, contracts as shown in FIG. 2, and pulls the plunger 7 to the left in the figure, thereby opening the passage 3 that had been blocked until then. Connect between both ports ■■.

Next, when discharging the residual pressure from the actuator side such as a cylinder, the solenoid 10 is turned on and the spool 2 is sucked against the elasticity of the compression spring 12, and the spool 2 is moved to the left in the figure as shown in FIG. Move it to the common port ■
When the passage 4 of the spool and the passage 4 of the spool are aligned, the ports (2) and (2) communicate with each other via the passage 4, and the residual pressure is discharged from the port (2).

At this time, if a speed controller (not shown), which is a throttle valve, is provided on the extension of port (2), the return speed of the actuator such as the cylinder can be adjusted. Furthermore, at this time, since the spool passage 3 is closed within the valve body 1, the power to the energized deformable member 9 may be either ON or OFF. After the residual pressure of the actuator has been discharged,
When the power to the solenoid 10 and the energized deformable member 9 is turned off, the spool 2 returns to its original state due to the elasticity of the compression spring 12, the plunger 7 also returns to its original state together with the spool 2, and the ports ■, ■, and ■ are all shut off. The state shown in FIG. 1 is reached.

Note that although a shape memory alloy is used in this embodiment as the electrically deformable member 9, the present invention is not limited to this, and any material that deforms when electrically applied, such as a piezoelectric ceramic or a bimetal, may be used.

Also, turn on this energized deformable member and solenoid.

By combining this device with a sequencer or the like, the OFF state can automatically control the three positions of the directional control valve in any order.

FIG. 4 shows another embodiment of the combination structure of the current-carrying deformable member 9 made of a shape memory alloy and the bias spring 8 in the above embodiment, in which a thick plastic vibe 21 and a thin A shape memory alloy 9 is stretched inside a plastic pipe 22 using maple terminals 23, and a bias spring 8 is interposed between both plastic pipes. In this device, when the shape memory alloy 9 is energized, Joule heat is generated and the temperature rises. When the operating temperature is exceeded, the shape will be restored to the originally set shape.
It contracts against the elasticity of the bias spring 8. As a result, the plunger 7 is moved in the same way as in the previous embodiment.

In the above embodiment, in order to prevent the positions of the opening ends of the passages 3 and 4 on the outer periphery of the spool 2 and each port from shifting in the circumferential direction of the spool 2, Of course, this has a rotation preventing structure such as a square cross section of the bore 1a to be fitted therein.

Further, although this embodiment has been described as controlling the direction of the normal gas flow, it is of course possible to control the direction of the hydraulic flow.

〔Effect of the invention〕

As explained above, according to the present invention, in a directional control valve that controls three positions, only one solenoid is required instead of the conventional two solenoids, which reduces costs by reducing the size of the valve. Since the solenoid is not bulky, effects such as high-density piping can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, FIG. 2 is an explanatory view of the action of the plunger in a state in which the plunger is moved by energizing the energized deformable member in FIG. 1, and FIG. FIG. 4 is a side view of another embodiment of the operating portion of the combination of the energized deformable member and the bias spring; FIG.
The figure shows a conventional directional control valve using JIS symbols. ■・・・First port, ■・・・Second port, ■・・・Common port (third port), 1
... Valve body, 2 ... Spool, 3.4
...Passage, 7...Plunger, 9...
...Electric deformable member, 10...Solenoid.

Claims (1)

[Claims] (1) A valve body having three ports, a first fluid pressure passage provided within the valve body and communicating the first port and third port of the valve body, and a second port. and third
a spool having a second fluid pressure passage that communicates with the port independently of the first passage; and driving the spool to alternately connect the two passages of the spool to each port of the valve body. A directional control valve comprising a corresponding solenoid, a plunger that is slidably provided in the spool and opens and closes a first passage, and an energized deformable member that performs a deforming operation when energized to drive the plunger.