JPS6216245Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piezoelectric chuck that utilizes the large voltage displacement of a piezoelectric bimorph made of piezoelectric ceramic.

In general, piezoelectric bimorphs made of piezoelectric ceramics are used in speakers and relays because they can obtain large displacements with relatively low voltage by utilizing their bending mode. The present applicant has proposed a bimorph type piezoelectric drive body in which a plurality of rectangular piezoelectric bimorphs are connected in a sequentially folded state. FIG. 1 shows a perspective view of a rectangular bimorph, in which rectangular piezoelectric ceramics 1a and 1b made of lead zirconate titanate are coated with conductive electrodes 2a and 2b such as silver on both sides and baked. , are brought into contact with both sides of a metal terminal 3 made of a metal plate such as copper, and are bonded with an adhesive having a strong adhesive force such as Araldite. Note that the outer electrode 2a of one of the rectangular piezoelectric ceramics 1a is
However, since the metal terminal 3 serves as a common electrode, the electrode 2a may not be provided at the end of one side of the piezoelectric ceramic 1a, and the folded electrode 4 may be provided between this portion and the metal terminal 3. If provided, electrical connection becomes easy.

When the piezoelectric ceramics 1a and 1b of the rectangular bimorph 5 configured in this way are each polarized in the thickness direction, the electrodes 2a and 2b are connected and a DC voltage is applied in series between the folded electrode 4 and the electrode 2a or 2b. When applied, the rectangular bimorph 5 is displaced in an arcuate manner in a certain direction depending on the polarity of the DC voltage.

Rectangular bimorph 5 made as above
A bimorph piezoelectric drive body can be constructed by sequentially connecting a plurality of piezoelectric actuators in a folded manner. That is, as shown in FIG.
One end 6A is a free end, and the other end 6B is folded back to the other end 7B of the next rectangular bimorph 7, and is bound by an elastic member 9 such as rubber or elastic resin. One end 7A of the rectangular bimorph is further connected to one end 8A of the next rectangular bimorph 8 by a semicircle or a rigid member 10 such as a solidified adhesive.

In the bimorph type piezoelectric drive body configured in this way, the electrodes on both sides of the rectangular bimorphs 6, 7, and 8 are connected, and a DC voltage is applied in parallel between the respective folded electrodes. When 6A is fixed, this rectangular bimorph 6
is bent in proportion to the voltage due to the vibration principle of a cantilever beam, and the other end 6B is displaced in a fixed direction. Also, since one end 7A of the rectangular bimorph 7 is in a fixed state,
The other end 6B of the rectangular bimorph 6 and the other end 7B of the rectangular bimorph 7 connected by the elastic member 9
is bent in the same direction as the other end 6B of the rectangular bimorph 6. Furthermore, since one end 8A of the rectangular bimorph 8 is connected to one end 7A of the rectangular bimorph 7 by the rigid member 10 and is in a fixed state, the other end 8B of the rectangular bimorph 8 is the same as the other end 6B of the rectangular bimorph 8. Since it bends in the direction, the rectangular bimorph 6
The displacement of the other end 8B of the rectangular bimorph 8 as seen from the fixed end 6A of is three times the displacement of the other end 6B of the rectangular bimorph 6.

The present invention fixes one end of each of a plurality of piezoelectric drive bodies configured in this way to the inner surface of the outer casing,
The piezoelectric actuators are arranged radially toward the center, and a chuck is provided at the other end of each piezoelectric actuator. The present invention provides a piezoelectric chuck that can be used to attach and detach objects. Embodiments will be described in detail below with reference to the drawings.

3 and 4 show a plan view and a front cross-sectional view of a piezoelectric chuck according to an embodiment of the present invention, in which numerals 11, 12, 13, and 14 are piezoelectric actuators, and these piezoelectric actuators The bodies 11 to 14 each have one end fixed to the inner surface of the outer casing 15 and are arranged radially toward the center.
A chuck tool 16, 1 is attached to the other end of 3, 14, respectively.
7, 18, 19 are fixed, and these chuck tools 16, 17, 18, 19 are arranged so as to form a circle with respect to the center.

In the piezoelectric chuck of this embodiment configured in this manner, by applying a DC voltage electrically in parallel to the piezoelectric drivers 11 to 14, these piezoelectric drivers 11 to 14 are displaced toward the center. Therefore, the chuck tools 16 to 19 move toward the center and perform a chuck action.

In addition, in the above embodiment, the chuck tools 16 to 19
Although the entire structure is circular, it may also be formed into a rectangular or polygonal shape, and the number of piezoelectric actuators may be reduced to 2.
It is possible to configure the chuck accordingly. Further, in the above embodiment, the outer casing 15
Although it is assumed to be annular, it may be rectangular or may cover the entire surface except for the part to be chucked. In addition, the output voltage of the bimorph generated by the impact of an object that comes into contact with the chuck is detected, and the electric circuit installed in each piezoelectric drive body is operated individually to change the voltage applied to this piezoelectric drive body. Therefore, the displacement of the piezoelectric drive body and the pressure of the chuck can be varied.

As explained above, according to the present invention, piezoelectric actuators composed of rectangular bimorphs are arranged radially from the outer casing toward the center, and a chuck is fixed to the other end of the piezoelectric actuator. Since a direct current voltage is applied in parallel to the body and each piezoelectric drive body is displaced toward the center, the object to be chucked can be easily attached and detached.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a rectangular bimorph, FIG. 2 is a front sectional view of a bimorph piezoelectric drive body according to an embodiment of the present invention, and FIG. 3 is a diagram of a piezoelectric chuck according to an embodiment of the present invention. The plan view, FIG. 4, is a front sectional view of FIG. 3. 1a, 1b...piezoelectric ceramic, 2a, 2b, 4...
Electrode, 3... Metal terminal, 5, 6, 7, 8... Rectangular bimorph, 9... Elastic member, 10... Rigid member, 11-14... Piezoelectric drive body, 15... Outer casing,
16-19... Chick tools.

Claims (1)

[Scope of utility model registration request] One end of a plurality of bimorph type piezoelectric actuators consisting of a plurality of rectangular bimorphs joined in tandem is connected to the inner surface of an outer casing and arranged radially from the outer casing toward the center, and the bimorph type piezoelectric actuator is A piezoelectric chuck characterized in that a chuck device is provided at each other end of the chuck.