JPS62159877A - Actuator - Google Patents

Abstract

PURPOSE:To obtain a piezo-electric actuator which can obtain a large displacement by bringing the end part of one of doubly provided piezo-electric element laminated bodies into contact with an output shaft while the end part of the other into contact with a case and connecting both of said laminated bodies with a holder. CONSTITUTION:Laminated bodies 14 consisting of piezo-electric elements are at least doubled, and the end part of an inside piezo-electric element is brought into contact with an output shaft 8 while the end part of an outside piezo-electric element is brought into contact with a case 13. Since both the piezo-electric elements are connected by holders 17a, 17b, the displacement quantity of the piezo-electric elements can be increased without need for increasing the length of the piezo-electric elements, obtaining a piezo-electric actuator having a large displacement.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an actuator using a piezoelectric element, and is used, for example, in a fluid control valve.

(Prior Art) Conventionally, as an actuator for a fluid control valve, for example, as shown in Japanese Patent Application Laid-Open No. 60-14'6978,
An electromagnetic valve that drives a valve body by excitation of an electromagnet is known.

(Problems to be solved by the invention) However, such electromagnetic actuators,
There is a problem with responsiveness, and if an attempt is made to improve this, the actuator itself has to become larger, and the large current generates heat. One possible solution to this problem is to use a so-called ceramic actuator in which a large number of piezoelectric elements are laminated, but while this has good response, the displacement is small. In order to increase this displacement, it is possible to increase the number of laminations and layers of piezoelectric elements, but this would make the laminate longer in one direction.

Therefore, the object of this invention is to provide an actuator such as a fluid control valve that is compact and can be operated at high speed.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a structure in which a laminate in which a large number of piezoelectric elements are laminated is provided at least twice, and one end of the first laminate is provided. comes into contact with the output shaft, and the second
One end of the laminate contacts the case, and the other end of the first laminate and the other end of the second laminate are connected via a holder.

(Function) When the piezoelectric elements of the first and second laminates are energized, their internal crystal structures change and each laminate is simultaneously displaced in one direction, and since these are connected by the holder,
The displacements of both of them are added up, and the displacement as a whole becomes large, so that the above-mentioned problem can be achieved.

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which one of the seven cutuators of the present invention is applied to a fluid control valve. The actuator 2 is connected to the upper part of the actuator 2.

The valve part l has a body 3, and a fluid artificial passage 4 and a fluid outlet passage 5 are formed in the lower part of the body 3, and a connecting part between the fluid inlet passage 4 and the fluid outlet passage 5 is formed. A valve seat 6 is formed.

Further, a valve stem sliding hole 7 is formed in the center of the body 3, and a valve stem 8 serving as an output shaft of an actuator 2, which will be described later, is slidably inserted into this valve body sliding hole 7. The tapered tip portion seats on the valve seat 6 and blocks communication between the fluid artificial passage 4 and the fluid outlet passage 5. By displacing the valve stem 8 upward, the fluid inlet passage 4 and the fluid outlet passage 6 are brought into communication. Further, the upper part of the body 3 is expanded into a cylindrical shape to form a large diameter part 9, and this large diameter part 9 and the lower outer periphery of a case 13, which will be described later, are screwed together. Furthermore, four spring storage parts 10 are formed in the center of the bottom surface of the large diameter part 9 in the axial direction, and the flange-shaped spring receiver formed at the upper end of the spring storage recess 10 and the valve body 8 is connected to the part 11. A spring 12 is loaded between them, and the spring 12 biases the valve stem 8 in the opening direction.

As shown in FIG. 2, the actuator 2 has a case 13 that is screwed into the large diameter portion 9 of the body 3 described above. This case I3 has a cylindrical shape with a closed upper end, and for example, triple stacked bodies 14a and 14c are arranged inside the case 13. As shown in FIG. 3, these laminates 148 to 14C are arranged between an electrode plate 15a connected to the positive side and an electrode plate 15b connected to the negative side, except for the ends where holders 17a and 17b, which will be described later, come into contact. It is constructed by stacking a large number of these with piezoelectric elements 16 in between. Piezoelectric element 16
is made of a well-known ceramic semiconductor having a piezo effect, such as TiBa0z or BaTi01.

The first stacked body 14a placed at the center has a solid cylindrical shape, and its lower end is in contact with the upper end surface of the valve body 8, which is the output shaft, and its upper end is closed. It is in contact with the inner surface of the upper end of the cylindrical first holder 17a. 1st
A second laminate 14b arranged around the laminate 14a of
has a hollow cylindrical shape, and its lower end abuts on a first flange portion 18a formed on the outer periphery of the lower end of the first holder 17a, and its upper end has the same shape as the first holder 17a but has a larger size. It is in contact with the inner surface of the upper end of the second holder +7b. The third laminate 14c arranged around the second laminate 14b has a hollow cylindrical shape like the second laminate 14b, and is connected to the first and second laminates 14a.

14b, and its lower end is concentric with the second holder 17b.
The second flange portion 18b is formed on the outer periphery of the lower end of the case 13, and the upper end thereof is in contact with the inner surface of the upper end of the case 13 described above. The first and second holders 17a and 17b are each made of a conductor and are used as electrodes that sandwich the piezoelectric element 16 together with an electrode plate on the opposite side of the holder.

In the above configuration, when the laminates 14a to 14c are not energized, each piezoelectric element 16 is not displaced, as shown by the solid line in FIG. the fluid control valve is in the open position, the fluid control valve is in an open state, and fluid enters from the fluid inlet passage 4 and passes between the valve stem 8 and the valve seat 6. , exits from the fluid outlet passage 5. Here, each laminate 1
．． When the energizing circuit to 1a-14c is closed, the electrode plate 15
A, 15b or boulders 17a, 17b and the electrode plate, a voltage is applied, current flows through each piezoelectric element 16, each piezoelectric element 16 mainly extends in the lamination direction, each laminated body 143-14c, As shown in FIG. 3, Δh1. Δ
h2. It is displaced in the axial direction by Δh (Δh3 is not shown). Therefore, one end of the outermost stacked body 14c is in contact with the case 13, and each stacked body 14a-14C is attached to the holder 17.
a.

17b, each displacement Δh5. Δh2. Δh3 acts on the valve stem 8 in the form of a sum, and this valve stem 8 moves downward against the spring 12, and its tip portion seats on the valve seat 6, and the fluid inlet passage 4 and the fluid outlet passage 5 are This shuts off communication with the fluid control valve and closes the fluid control valve.

In the above embodiment, the holders 17a and 17b were used as electrodes, but they may be made of synthetic resin or the like without being used as one holder, and the electrodes may be arranged in such a way that they are stacked alternately. It is not limited to this as long as the piezoelectric element 16 can be energized, and the holders can also be brought into contact with each other internally.

Further, in the above embodiment, the laminate is triple-layered, but it is sufficient that the laminate is 2 or more layers, and the displacement can be increased each time the number of laminates is increased. Laminated body 14
case 13 on a, second or third laminate 14b on the periphery
, 14c may be brought into contact with the valve rod 8, respectively. Furthermore, although the above embodiment has been described as an actuator used for a fluid control valve, it is needless to say that the present invention is not limited to this and can be applied to other actuators.

(Effects of the Invention) As described above, according to the present invention, since a plurality of annular piezoelectric element laminates are arranged around a central piezoelectric element laminate, it can be made compact, and the laminates can be made compact. Since the laminates are connected by a holder and the displacements of each laminate are added together, a large displacement can be obtained. Furthermore, since it uses a piezoelectric element, it has excellent responsiveness and other effects.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the actuator used in the above, and FIG. 3 is a sectional view showing the internal configuration and wiring state of the actuator used in the above. 2...Actuator, 13...Case, 14a~
14c...Laminated body, 16...Piezoelectric element, 17a, 1
1b---Holder. Figure 1 '56 [Figure 2 Figure 3

Claims (1)

[Claims] At least two laminates each consisting of a large number of piezoelectric elements
one end of the first laminate is in contact with the output shaft,
An actuator characterized in that one end of the second laminate contacts a case, and the other end of the first laminate and the other end of the second laminate are connected via a holder.