JP2568195Y2 - Linear actuator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low power consumption and high output linear actuator.

[0002]

2. Description of the Related Art Conventionally, as one of linear actuators used for opening and closing various valves, there is a solenoid actuator, which is composed of a combination of an electromagnetic coil and a plunger made of a magnetic material. It moves forward and backward, moves the valve body of various valves forward and backward, and performs opening and closing operations of the valves.

[0003]

However, such a solenoid actuator still has the following problems to be solved.

That is, in order to increase the output, it is necessary to increase the diameter of the coil or to apply a large voltage, so that the size of the actuator is increased and the power consumption is increased.

An object of the present invention is to provide a linear actuator which can solve the above-mentioned problems.

[0006]

According to the present invention, there is provided an inner case having a fixed volume capable of enclosing a water-absorbing polymer gel therein and allowing an electrolyte to pass therethrough, and an inner case provided on the outer periphery of the inner case. A housing in which an electrolyte is sealed in an annular space formed between the housings; a plunger which can enter the water-absorbing polymer gel in the inner case through a through hole provided in a front wall of the housing; a water-absorbing polymer gel and the plunger A linear actuator comprising a stretchable bellows interposed between the bellows, positive and negative electrodes respectively disposed in the water-absorbent polymer gel and the electrolytic solution, and a power supply for applying a voltage to both electrodes. It is.

In the linear actuator having the above structure, for example, sodium polyacrylate can be used as the water-absorbing polymer gel, and sodium sulfate can be used as the electrolyte.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on an embodiment shown in the accompanying drawings.

(Construction) As shown in FIG. 1, a housing 10 forming an outer shell of a linear actuator A has a tubular wall 11 having a rear end opening, and a packing 12 provided at the rear of the tubular wall 11 via a packing 12. And a rear wall 13 connected in a sealed state. Reference numeral 14 denotes a connection cylinder provided on the outer peripheral surface of the cylindrical wall 11 and the rear wall 13 in order to strengthen the connection between the cylindrical wall 11 and the rear wall 13.

A cylindrical inner case 15 is disposed concentrically within the housing housing 10 having the above-described structure. A gel-filled space 16 is formed in the inner case 15, and an outer periphery of the inner case 15 is formed. Surface and housing 10
An electrolyte-filled space 17 is formed between the inner space and the inner peripheral surface.

The gel-filled space 16 is filled with a water-absorbent polymer gel 18 such as sodium polyacrylate,
On the other hand, the electrolyte sealed space 17 contains sodium sulfate (NaSO ₄ ).
Electrolyte solution 19 made of such as is sealed.

The inner case 15 is formed of, for example, a rigid cylinder made of a permeable metal or rigid resin having a fine mesh, and the electrolytic solution 19 is filled in the gel-filled space 16.
And the electrolyte solution-filled space 17 can freely enter and exit.

A through hole is formed in the front wall 10a of the housing 10.
A rear end of the plunger 21 enters the water-absorbent polymer gel 18 sealed in the gel sealing space 17 in the axial direction through the through hole 20.

Further, the plunger 21 and the water-absorbing polymer gel
An elastic bellows 22 is interposed between the bellows 18 and the bellows 22. The bellows 22 adheres the back surface of the central portion 22a to the rear end surface of the plunger 15, and attaches the peripheral edge portion 22b to the plunger 15.
The front wall 10a of the housing 10 is bonded to a portion around the through hole 20.

In the water-absorbent polymer gel 18, a disc-shaped negative electrode 23 is provided along the inner surface of the rear wall 13 of the housing 10, while a cylindrical positive electrode 23 is provided. Electrode 24
Are arranged concentrically with the housing 10 in the electrolytic solution 19.

One end is connected to the negative electrode 23 and the other to the positive electrode.
Lead wires 25 and 26 connected to 24 are plugs provided on rear wall 13.
It is led out of the housing 10 through 27 and 28, and a power supply 29 and an open / close switch 30 are interposed between the lead-out ends.

When the open / close switch 30 is closed to the electrodes 23 and 24 and a voltage is applied from the power supply 29, the water-absorbent polymer gel 18 absorbs water and its volume increases.
Through the bellows 22, the plunger 21 advances in the axial direction.

On the other hand, by applying a reverse voltage to both electrodes 23 and 24, the plunger 21 can be retracted.

(Operation) Hereinafter, the operation of the linear actuator A according to the present invention will be described with reference to FIG.

FIG. 1 shows a state in which a voltage has not yet been applied to the negative electrode 23 and the positive electrode 24, and the plunger 21 is in a retracted position shown by a solid line.

Next, when a voltage is applied to the negative electrode 23 and the positive electrode 24 by closing the open / close switch 30, the water-absorbing polymer gel 18 in the inner case 15 is
Water is absorbed from the electrolyte solution 19 through the inner case 18 and the volume thereof is increased. Due to this increase in volume, the plunger 21 advances in the axial direction via the bellows 22, and assumes the advanced position indicated by the dotted line.

On the other hand, when a reverse voltage is applied to the negative electrode 23 and the positive electrode 24, the electrolyte solution 19 is discharged from the water-absorbing polymer gel 18 in the inner case 15 into the housing 10 through the inner case 18. The volume of the water-absorbing polymer gel 18 decreases. Due to this reduction in volume, the plunger 21 retreats in the axial direction via the bellows 22, and assumes a retreat position shown by a solid line.

Thus, the voltage required to cause the water-absorbing polymer gel 18 to increase or decrease its volume may be extremely small, but a large thrust can be applied to the plunger 21 by increasing or decreasing the volume. That is, it is possible to provide the low-consumption, high-output linear actuator A.

Next, an example of use of the linear actuator A will be described with reference to FIG.

[0025] FIG 2 is a linear actuator A according to the present invention is an automatic valve V ₁ which is configured to drive the valve body V of the diaphragm type, 40 is a valve body, respectively, the primary piping and the secondary An inflow path 41 and an outflow path 42 are provided for communication with the pipe.

In the valve box 40, a main valve hole 43 is formed between the inflow path 41 and the outflow path 42, and a main valve seat 44 is formed around the upper end opening of the main valve hole 43. I have.

On the main valve seat 44, a diaphragm 45 also serving as a main valve body for opening and closing the main valve hole 43 is provided.

Above the diaphragm 45, a diaphragm back chamber 46 is formed. The diaphragm back chamber 46 is connected to an inflow passage through an orifice 47 provided on the periphery of the diaphragm 45.
Communicates with 41.

Reference numeral 48 denotes a pilot valve hole formed in the diaphragm 45, and connects the diaphragm back chamber 46 to the outflow passage 42.

A pilot valve element 49 provided at the lower end of the plunger 21 of the linear actuator A faces the pilot valve hole 48, and the pilot valve hole 48 is opened and closed by the operation of the linear actuator A.

In FIG. 2, reference numeral 50 denotes a protective cover;
Is a watertight packing, and 52 is a packing holder.

[0032] With the above configuration, the automatic valve V ₁ was a self-servo effect with the valve body V of the diaphragm type, that the diaphragm 45 for opening and closing the main valve seat 44 so as to follow the movement of the plunger 21 of the linear actuator A it can.

However, as described above, in the present invention,
The linear actuator A is configured to generate a thrust to the plunger 21 by utilizing the increase / decrease of the volume of the water-absorbent polymer gel 18 due to the application of a voltage. The voltage required to cause the volume increase / decrease of the water-absorbent polymer gel 18 may be extremely small, but a large thrust can be applied to the plunger 21 by the volume increase / decrease. Therefore, a low-power, high-output linear actuator A
In the automatic valve V ₁ can be opened and closed, it is possible to achieve energy saving and miniaturization of the linear actuator A.

[0034]

[Effects of the Invention] As described above, in the present invention,
A linear actuator is enclosed in a water-absorbent polymer gel and has a fixed volume that allows the electrolyte to pass through.A linear actuator is provided on the outer periphery of the inner case, and an annular space is formed between the inner case and the electrolyte. , A plunger that can enter the water-absorbing polymer gel in the inner case through a through hole provided in the front wall of the housing, and a telescopically interposed between the water-absorbing polymer gel and the plunger. It comprises a bellows, positive and negative electrodes disposed in the water-absorbent polymer gel and the electrolytic solution, respectively, and a power supply for applying a voltage to both electrodes.

Therefore, a slight voltage is applied to the water-absorbing polymer gel and the electrolyte to increase the volume of the water-absorbing polymer gel.
By causing the reduction, a large thrust can be applied to the plunger. Therefore, a low power consumption and high output linear actuator can be obtained, and energy saving and miniaturization of the linear actuator can be achieved.

[0036]

[Brief description of the drawings]

FIG. 1 is an overall sectional configuration diagram of a linear actuator according to the present invention in a state where no voltage is applied.

FIG. 2 is a sectional front view of the automatic valve to which the linear actuator according to the present invention is applied.

[Explanation of symbols]

 A Linear actuator 10 Housing 15 Inner case 18 Water absorbing polymer gel 19 Electrolyte 20 Through hole 21 Plunger 22 Bellows 23 Electrode 24 Electrode

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Keishi Horiuchi 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Tochiki Kiki Co., Ltd. (56) References JP-A-63-309532 (JP, A) JP-A-2-283980 (JP, A) JP-A-3-701 (JP, A) JP-A-1-102580 (JP, U)

Claims (3)

(57) [Scope of request for utility model registration] 1. An inner case (15) having a constant volume, in which a water-absorbing polymer gel (18) is sealed and an electrolyte is permeable.
Provided on the outer periphery of the inner case (15), the inner case (1
The inner case (15) passes through a housing (10) in which an electrolyte (19) is sealed in an annular space formed between the housing (10) and a through hole (20) provided in a front wall (10a) of the housing (10). A plunger (21) that can enter into the water-absorbent polymer gel (18), and a stretchable bellows (22) interposed between the water-absorbent polymer gel (18) and the plunger (21), Positive and negative electrodes (23) (24) disposed in the water-absorbent polymer gel (18) and the electrolyte (19), respectively, and a power supply (30) for applying a voltage to both electrodes (23) (24) A linear actuator comprising: 2. The linear actuator according to claim 1, wherein the water-absorbing polymer gel (18) is sodium polyacrylate. 3. The linear actuator according to claim 1, wherein the electrolyte is sodium sulfate.