JPH0191675A - Actuator - Google Patents

Abstract

PURPOSE:To enable the working of various devices, machines, and the like to be controlled at precision, by fitting a plunger concentrically and movably forward or backward along an axis, into a cylindrical actuator casing provided with front and rear walls. CONSTITUTION:So far as an actuator A is concerned, a plunger d is fitted concentrically and movably forward or backward along an axis, into a cylindrical actuator casing provided with front and rear a walls a, b. Besides, a piezoelectric element assembling unit B consisting of three piezoelectric elements e, f, g is concentrically is set on the outer peripheral surface of the plunger d. The piezoelectric elements e, f, g, are composed to be contracted when a power source is turned ON. In other words, the piezoelectric elements e, f, g are expanded in a state that current is not conducted to, and the plunger d is clamped by the elements, and in a state that current is conducted to, the elements are contracted to release the plunger d. In the meantime, the piezoelectric element g is in a state that it is expanded in the axial direction on the plunger d in a state that current is not conducted, and in a state that current is conducted, the element is contracted on the plunger d, and the full length in the axial direction is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a direct acting actuator used to operate various devices.

(b) Prior Art Conventionally, various types of actuators, such as mechanical actuators, electrical actuators, and fluid actuators, have been known as such actuators.

And by using such an actuator,
Various devices, machines, etc. can be made to perform desired operations automatically.

(c) Problems to be Solved by the Invention However, none of these conventional actuators could perform highly accurate positioning and could not precisely control the operations of various devices and machines.

An object of the present invention is to provide an actuator that can solve the above problems.

(d) Means for Solving the Problems The present invention provides a plunger that is installed in a cylindrical actuator casing having front and rear walls so as to be movable back and forth concentrically and along the axis. A ring-shaped piezoelectric element is arranged inside the front and rear walls, and a cylindrical piezoelectric element is interposed between the piezoelectric elements, and the plunger can be clamped by applying voltage to the piezoelectric element. In addition, the actuator is characterized in that a voltage is applied to the piezoelectric element to make it expandable and retractable in the axial direction of the plunger, and an elastic body is interposed between the inner surface of one of the front and rear walls and the piezoelectric element. This is related.

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

■The actuator moves the plunger forward and backward by activating three piezoelectric elements, so it can move the plunger forward and backward in μm order or sub-μ order depending on the number of voltage applications, making it suitable for various devices and machines. etc. can be operated precisely.

■The actuator can move the plunger forward and backward on the μm order or sub-μm order, so
Various devices and IJS! There is no need to interpose a speed reduction mechanism or the like between the drive device and the driven object such as a machine, and the overall structure of various devices and machines can be made extremely compact.

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

FIG. 1 shows the configuration of an actuator A 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,
Three piezoelectric elements e.

It is constructed by arranging a piezoelectric element assembly B consisting of 12 g.

The piezoelectric elements e, f, and g are configured to contract when the power is turned on.

That is, the piezoelectric elements e and f extend and clamp the plunger d when not energized, and contract and release the plunger d when energized. - side, piezoelectric element g
is extended in the axial direction on the plunger d when it is not energized, and when it is energized, it contracts on the plunger d, shortening its total length in the axial direction.

The plunger d then connects these three piezoelectric elements e and f.
, g can be moved in the axial direction by appropriately controlling.

As shown in FIGS. 1 and 2, the piezoelectric elements e and f are ring-shaped elements formed by laminating a large number of piezoelectric element pieces concentrically around the axis of the plunger d, and the ring is attached to the plunger d. Electrodes are attached to the outside as well as the inside in contact with d, and the ring is configured to contract when a voltage is applied.

Moreover, as shown in FIGS. 1 and 3, the piezoelectric element g is
It is a cylindrical element formed by laminating a large number of piezoelectric element pieces at right angles to the axis of the plunger d. Electrodes are provided at both ends of the cylinder, and it is configured to contract by applying a voltage to both ends. ing.

Furthermore, h is an elastic body such as a disc spring interposed between the rear end of the piezoelectric element g and the rear wall, and the piezoelectric element e.

The piezoelectric element assembly B is integrated by always elastically pressing f and g toward the front wall a.

Further, in FIG. 1, i and j are U seals provided to improve the watertightness of actuator A.

Note that in the above configuration, piezoelectric elements e, r, g
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 many times by the piezoelectric elements e, f, and g, it has a small linear expansion coefficient, high hardness, strength, creep resistance, and wear resistance, and has high processing accuracy. It is preferable to use a ceramic material, for example, a ceramic material.

Next, the movement of the plunger d by the actuator A having such a configuration will be explained with reference to FIGS. 6 to 8.

As shown in FIG. 6, the plunger d is clamped while leaving the piezoelectric element f as it is, and a voltage is applied to the piezoelectric element e to contract it and release the plunger clamp.

Next, as shown in Fig. 7, when a voltage is applied to the piezoelectric element g to contract it, the piezoelectric element ``moves in the direction of the arrow, and the plunger d clamped by the piezoelectric element f also moves in the same direction. do.

Thereafter, as shown in FIG. 8, when a voltage is applied to the piezoelectric element f to release the clamp of the plunger d and at the same time the voltage applied to the piezoelectric element g is released, the piezoelectric element g extends in the direction of the arrow, and the piezoelectric element f also extends in the same direction.

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.

Further, FIG. 9 shows an application example of the actuator A according to this embodiment, which is an example in which the actuator is applied to an automatic opening/closing valve that functions as a hot water mixing line.

In FIG. 9, reference numeral 10 denotes a casing in the form of a cylindrical box, and the casing 10 has two cylindrical bodies 11 and 12 with openings at both ends protruding from the negative side wall thereof, and a single tube inside. It forms side channels 13,14.

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

On the other hand, the inner opening ends 13b, 14 of the − side flow path 13.14
b communicate with compartments 17 and 18 formed at both ends of the casing 10, respectively.

Further, a T-shaped cylinder 19 with openings at both ends protrudes from the other side wall of the casing 10, and a T-shaped other side flow path 20 is formed in the T-shaped cylinder 19. There is.

The other side flow path 20 functions as a mixed water flow path of a hot and cold water mixer faucet, and its outer open end 20a communicates with the mixed water pipe 21, while its inner bifurcated open end 20b , 20c communicate with compartment 17.18.

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.
2, 23, inner bifurcated opening ends 20b, 20c
Valve bodies 24 and 25 made of diaphragm valves that open and close are provided.

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

Each actuator A has a plunger d whose tip can come into contact with the rear part of the valve body 24.25.
．． 25 can be opened and closed freely.

In addition, in FIG. 9, 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 unit, and causes the control unit to automatically control the temperature based on the detected value. Both actuates A of the on-off valve are operated to control the temperature appropriately.

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 actuators A of the automatic opening/closing valve based on the detected value, the valve body 24.25 opens at the set opening degree. Open and close the - side flow path 13.14
The amount of water supplied and the amount of hot water flowing into the other side channel 20 can be mixed at a constant mixing ratio.

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

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

■Actuator A has three piezoelectric elements e and f.

Since the plunger d is moved forward and backward by operating g, the plunger d can be moved forward and backward on the μm order or sub-μm order depending on the number of voltage applications, and various devices and machines can be operated precisely. can be done.

■Since the actuator A can move the plunger d forward and backward on the μm order or sub-μm order, there is no need to interpose a speed reduction mechanism etc. between the actuator and driven objects such as various devices and machines. The overall structure can be made extremely compact.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of an actuator according to the present invention, FIGS. 2 and 3 are cross-sectional views taken along lines 1-I and 1-n in FIG. 1, and FIGS. 4 and 5 are views of other embodiments. A cross-sectional view of the piezoelectric element according to the example, FIGS. 6 to 8 are explanatory views of the operating state of the actuator, and FIG. 9 is a cross-sectional side view of an automatic on-off valve equipped with the above-mentioned actuator. In the figure, A: actuator B: piezoelectric element assembly a: front wall b: rear wall C: actuator casing d nib plunger e: piezoelectric element f: piezoelectric element
g: Piezoelectric element h: Elastic body Figure 1 Figure 6 Figure 8

Claims (1)

[Claims] 1. A plunger (d) is 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.
Ring-shaped piezoelectric elements (e) and (f) are disposed on the outer circumferential surface of d) and located inside the front and rear walls (a) and (b), and the piezoelectric elements (e) and (f) are A cylindrical piezoelectric element (g) is interposed in the piezoelectric element (g), and a voltage is applied to the piezoelectric elements (e) and (f) to enable clamping of the plunger (d), and a voltage is applied to the piezoelectric element (g). The plunger (d) is expandable and retractable in the axial direction, and an elastic body (h) is interposed between the inner surface of one of the front and rear walls (a) and (b) and the piezoelectric element (f). actuator.