JPH01202179A - Fine distance stepless drive type actuator - Google Patents

Abstract

PURPOSE:To effectively control a flow rate by providing a manual resetter for pressing or rotating a plunger to move it forward. CONSTITUTION:A fine distance stepless drive type actuator A is composed by telescopically attaching a plunger (d) along an axis concentrically within a cylindrical actuator casing (c) having front and rear walls (a), (b), and arranging a piezoelectric element assembly B made of 4 piezoelectric elements (e)...(h) concentrically on the outer periphery. The elements (g), (h) are disposed at the center on the casing, and cantilever elastic bridges (i), (j) are secured at the base ends to the elements (g), (h). The plunger (d) can be moved in an axial direction by controlling the sequence of applying a voltage to the elements (e)...(h). In this case, a manual reset button (p) is attached to the position opposite to the plunger (d) at the center of the wall (b). A flowout accident can be prevented by pressing it.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a minute distance stepless drive type actuator used for operating various devices.

(b) Conventional technology Conventionally, micro-distance stepless drive actuators such as piezoelectric actuators and stepping linear motors have been known as a means of performing high-precision positioning and precisely controlling the operations of various devices and machines. It is being

(c) Problems to be Solved by the Invention However, in such an actuator, when used, for example, in an on-off valve, the plunger may stop at the valve open position during a power outage or the like.

If such a state is left as it is, the objects to be transported, such as fluids, will be thrown away, and depending on the objects to be transported, it may lead to a dangerous accident.

An object of the present invention is to provide a minute distance stepless drive type actuator that can solve the above problems.

(d) Means for solving the problem The present invention provides a micro-distance stepless actuator in which a plunger is installed in the actuator casing so that it can move forward and backward steplessly in small steps along the axis, in which the plunger is pressed or rotated. The present invention relates to a minute-distance stepless drive type actuator characterized by being provided with a manual return section for moving forward.

In addition, here, micro-distance stepless drive actuators include laminated piezoelectric actuators, piezoelectric bimorph actuators, stepping linear motors, piezoelectric linear motors, ultrasonic linear motors, combinations of ultrasonic motors (rotary type) and rotating screws, and stepping motors. (rotary type) and a rotating screw.

(e) Actions and Effects With the configuration described above, the present invention has the following actions and effects.

In the present invention, since a manual return section is provided that moves the plunger forward by pressing or rotating it, in the event of a power outage, etc., the plunger can be fully closed by pressing or rotating the manual return section. It is possible to quickly prevent objects to be transported from flowing out, thereby preventing losses, accidents, etc. due to flowing out.

(f) Examples The present invention will be specifically described below based on examples shown in the attached drawings.

FIG. 1 shows the configuration of a piezoelectric actuator A, which is one form of a minute distance stepless drive type actuator according to this embodiment.

As shown in the figure, the actuator A has a plunger d installed in a cylindrical actuator casing C having front and rear walls a and b so as to be movable back and forth concentrically and along the axis. Concentrically,
Four piezoelectric elements e, f.

It is constructed by arranging a piezoelectric element assembly B consisting of g+h.

Furthermore, in the illustrated embodiment, the piezoelectric element g+11 is disposed in the center of the actuator casing a,
It is fixed to the tip of a holder H whose base end is fixed to the front wall a.

Further, IIJ is a cantilever-shaped elastic bridge whose base end is fixed to the piezoelectric element g+h and whose tip end extends toward the front and rear walls a and b.

Piezoelectric actuators e and f are attached to the outer peripheral surfaces of the ends of the elastic bridges i and j, and I is fixed to the brake shoes on the inner peripheral surfaces thereof.

This piezoelectric element e+Lg+h is configured to contract when the power is turned off.

That is, when the piezoelectric elements e and f are energized, they expand and expand their inner diameters to release the clamp on the plunger d, and when they are not energized, they contract to reduce their inner diameters and clamp the plunger d. .

On the other hand, the piezoelectric element g+h extends in the axial direction on the plunger d when it is energized, and contracts on the plunger d when it is not energized, thereby shortening its total length in the axial direction.

The plunger d then connects these four piezoelectric elements e and f.
, g, and h are controlled by a control device C, which will be described later, to allow movement in the axial direction.

As shown in FIGS. 1 and 2, the piezoelectric elements e, f+g+h are cylindrical elements formed by laminating a large number of piezoelectric element pieces in the axial direction of the plunger d, and electrodes are provided at both ends of the cylinder. By applying a voltage across these ends,
It is configured to stretch.

Note that the piezoelectric element piece can be made of, for example, piezoelectric ceramics, and examples of such piezoelectric ceramics include AB
P ZT (P b (Z r.

Ti)03) system, or PLZT (Pb (Zr, Ti)
03], PT (PbTi03) system, or PZ
A three-component system based on T can be used.

The piezoelectric element e + f + g + h can also be formed by laminating a large number of thin ring-shaped piezoelectric element pieces in the axial direction around the axis of the plunger d, as shown in FIG. In this case, the direction of voltage application is changed by 90 degrees.

Further, in FIG. 1, m is a U seal with low sliding resistance, which is provided to improve the watertightness of the actuator A.

Note that in the above configuration, the piezoelectric element +3 + f +
g + h can have not only a circular cross section but also a rectangular cross section, for example, and can also be formed from divided pieces as shown in FIGS. 4 and 5.

In addition, since the plunger d is clamped to the brake shoe many times by l, it has a small linear expansion coefficient, high hardness, strength, creep resistance, and wear resistance, and has high processing accuracy. Desirably, for example, a ceramic material may be considered.

Furthermore, in this embodiment, the piezoelectric actuator A is
As shown in the figure, a manual return button p made of elastic rubber or the like is attached as a form of a manual return part at the center of the rear wall at a location facing the plunger d. When the manual return button p is pressed, its front surface protrudes forward and comes into contact with the rear end of the plunger d,
Push plunger d against the clamping force of piezoelectric elements e and f,
It can be pushed forward.

Therefore, if the plunger d stops with the valve etc. open during a power outage, etc., the manual return button p is immediately activated.
Press to close the valve completely to prevent spills, etc.

In addition, in this embodiment, the plunger d has a diameter-reduced tip q formed at its tip, and the tip q has an end surface area (pressure receiving area) that is significantly smaller than the cross-sectional area of the plunger d. There is.

Note that an elastic body is attached to the tip of the diameter-reduced tip q.

Therefore, when used in a valve, etc., as described later, the pressure receiving area can be significantly reduced, so the thrust force applied to the plunger d can be minimized, and the thrust force L'lE for driving the plunger d can be minimized. Yes, actuator A
Accurate driving is possible.

Furthermore, if the stepped portion of the plunger d is brought into contact with the rear surface of the front wall a when the plunger d is moved forward a certain distance (for example, at a fully closed position or a position slightly advanced than that), Further advancement of the plunger d can be restricted, and damage to the diaphragm, etc. of the on-off valve due to excessive advancement can be reliably prevented.

Further, FIG. 6 shows the configuration of a control device C for controlling the piezoelectric actuator A.

As shown, the control device C includes a microprocessor r
, input/output interfaces s and t, and the piezoelectric element e
It is composed of a memory U that stores a drive order program of 1LgJ.

Next, the movement of the plunger d by the actuator A having such a configuration will be explained with reference to FIGS. 7 to 9.

When the actuator drive button V shown in FIG. 6 is pressed, the control device C releases the voltage application to the piezoelectric element e and retracts the plunger d, as shown in FIG. 7, according to the drive order program read from the memory U. At the same time, a voltage is applied to the piezoelectric element f to extend the plunger d.
Release the clamp.

Next, as shown in FIG. 8, when a voltage is applied to piezoelectric element g+11 to extend it, piezoelectric elements e and f move in the direction of the arrow, and along with this, plunger d, which piezoelectric element e clamps,
also moves in the direction of the arrow.

Thereafter, as shown in FIG. 9, when a voltage is applied to the piezoelectric element e to release the clamp on the stretching plunger d, and at the same time, when the applied voltage to the piezoelectric element g+h is released, the piezoelectric element g+h contracts in the direction of the arrow, and the plunger d moves further in the direction of the arrow.

After that, by repeating the above operation, plunger d
can be moved in a linear manner with a stroke on the μm order or sub-μm order, and various devices and machines can be operated precisely.

In this embodiment, 1. As mentioned above, the piezoelectric actuator A is equipped with a manual return button p, so if the plunger d stops with the valve etc. open during a power outage, etc. , the valve can be completely closed by pressing the manual return button p immediately to prevent leakage accidents.

That is, as shown in Figure 10, when a power outage occurs (10
0), the power failure detection circuit is activated (101), and the piezoelectric element power supply circuit is cut off (102). As a result, piezoelectric elements e+f+g+h are all turned off and contracted, and in particular, piezoelectric elements e and f clamp plunger d and maintain the same clamping force (103).

Thereafter, the manual return button p is pressed to advance the plunger d against the clamping force to close the valve 104), thereby preventing spillage accidents and the like (105).

Further, FIG. 11 shows an application example of the actuator A according to this embodiment, and is an example in which the piezoelectric actuator A is applied to an automatic opening/closing valve that functions as a hot water mixing faucet.

In FIG. 11, reference numeral 10 denotes a casing in the form of a cylindrical box, and the casing 10 has two flow passages 13 and 14 formed on its side wall.

The − side flow paths 13 and 14 function as a water supply flow path and a hot water supply flow path for the hot and cold mixer faucet, and their outer open ends communicate with the water supply pipe 15 and the hot water supply pipe 16, respectively.

On the other hand, the inner opening ends of the − side flow paths 13 and 14 are, respectively,
It communicates with compartments 17,18 formed at both ends of the casing 10.

Further, a T-shaped other side flow path 20 having both ends open is formed in the other side wall of the casing 10 .

The other side flow path 20 functions as a mixing water flow path of a hot and cold water mixing faucet, and its outer open end communicates with the mixing water pipe 21, while its inner bifurcated open end is separated. It communicates with rooms 17 and 18.

Further, valve seats 22 and 23 are provided at the inner bifurcated opening of the T-shaped cylinder 19, respectively.
3, the valve seat 2 is moved back and forth in the axial direction within the casing 10.
Valve bodies 24 and 25, which are diaphragm valves that come into contact with and separate from 2 and 23 and open and close inner bifurcated opening ends, are provided.

Furthermore, piezoelectric actuators A are attached to both ends of the casing 10, respectively.

And each piezoelectric actuator A has its plunger d
The tips of the valve bodies 24 and 25 can freely come into contact with the rear parts of the valve bodies 24 and 25, so that the valve bodies 24 and 25 can be opened and closed.

In addition, in FIG. 11, 30 is a temperature sensor provided in the other side flow path 20, which detects the temperature of the mixed water, feeds back the detected value to the control section as shown in FIG. Automatically opens/closes both actuates A based on the detected value.
is operated by PID control or the like to control the appropriate temperature.

The operation of the automatic on-off valve having such a configuration will be briefly explained as follows.

That is, when the detected value from the temperature sensor 30 is fed back to the control section and the control section separately operates both piezoelectric actuators A of the automatic opening/closing valve based on the detected value, the valve bodies 24 and 25 are set to open. - side flow path 13
．． The amount of water supplied flowing from the flow path 14 to the other side flow path 20 and the hot water ffl can be mixed at a constant mixing ratio.

In this action, since the valve bodies 24 and 25 are operated by the piezoelectric actuator A,
Flow rate control can be performed more reliably, and appropriate temperature control can be performed more reliably.

In addition, in this control, as mentioned above, in the event of a power outage, etc., the plunger d can be moved forward by pressing the manual operation button q, and this movement quickly closes the automatic on-off valve. Then, stop water discharging to the drain, shower, etc.

It is possible to reliably prevent outflow losses and burn accidents due to continued water spouting.

As described above, this embodiment has the following functions and effects.

In this embodiment, a manual return button p for pressing the plunger d and moving it forward is installed on the rear wall of the actuator casing a facing the rear end of the plunger d, so that in the event of a power outage, etc. By simply pressing the same manual return button p, the plunger d can be moved to the fully closed position of an automatic on-off valve, etc., quickly preventing the flow of conveyed objects, etc., and preventing loss and burn accidents. can do.

In addition, in this embodiment, a button is used as the manual return unit, but instead of using a button, a pressing hole is provided between the parts,
You can also press the rear end of plunger d directly (
The rear wall of the piezoelectric actuator A is formed of an elastic material,
It is also possible to indirectly press the plunger d by pressing this rear wall.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a piezoelectric actuator which is one form of a minute distance stepless drive type actuator according to the present invention;
Figure 2 is a cross-sectional view taken along line 1-1 in Figure 1, Figures 3 to 5.
The figure is a cross-sectional view of a piezoelectric element according to another embodiment, FIG. 6 is an explanatory diagram of the configuration of the control device, FIGS. 7 to 9 are explanatory diagrams of the operating state of the actuator, and FIG. 10 is an illustration of the piezoelectric actuator during power outage. FIG. 11 is a cross-sectional side view of an automatic opening/closing valve equipped with the above-mentioned actuator. In the figure, A: piezoelectric actuator B: piezoelectric element assembly C: control device D: automatic on-off valve a: front wall b: rear wall C: actuator casing d0 plunger e: piezoelectric element f: piezoelectric element
g: Piezoelectric element h: Piezoelectric element p: Manual return button Patent applicant: TOTOKIKI CO., LTD.

Claims (1)

[Claims] 1. In a micro-distance stepless actuator in which a plunger (d) is installed in the actuator casing (c) so that it can move forward and backward steplessly in small steps along the axis, the plunger (d) is pressed. Alternatively, a minute distance stepless drive type actuator is provided with a manual return section that rotates and moves forward.