JPH0113680B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rocking motion generating mechanism, and more particularly to a rocking motion generating mechanism that generates rocking motion by applying a voltage to a piezoelectric body and causing displacement.

The oscillating motion in the present invention refers to a oscillating motion that reciprocates between a small negative angle, for example, about 1 degree. In order to generate such a rocking motion, it is possible to utilize the displacement that occurs when a voltage is applied to the piezoelectric body. By using an arm to expand the angular displacement obtained by a rocking motion generating mechanism that utilizes the displacement of a piezoelectric body, and converting it into a reciprocating motion of the tip of the arm, it is possible to generate a stroke proportional to the length of the arm. A reciprocating motion can be obtained. The reciprocating motion thus obtained is used as a mechanical drive source in piezoelectric relays, speakers, and the like.

FIG. 1 is a perspective view showing a conventional rocking motion generating mechanism. In the figure, one end of the piezoelectric bodies 31 and 32 is fixed to two parallel mounting surfaces facing each other of the mounting part 1 made of metal or plastic, and the other end of the piezoelectric bodies 31 and 32 is fixed to two parallel mounting surfaces facing each other. A movable part 2 of a plastic plate is fixed and supported parallel to the mounting surface.
The positions at which the ends of the piezoelectric bodies 31 and 32 are fixed to the movable part 2 are determined so that a force couple that causes the movable part 2 to swing acts when the piezoelectric bodies 31 and 32 expand and contract. The piezoelectric bodies 31 and 32 are plates made of piezoelectric material, and conductive wires 81 and 8 are connected to electrodes 71 and 72, which are provided in pairs on each side.
A voltage is applied through 2, and piezoelectric bodies 31 and 32 expand and contract in accordance with the applied voltage.

Figures 2a and 2b are side views showing the operation of the mechanism of Figure 1. Figure a shows a state in which no voltage is applied to the piezoelectric bodies 31 and 32 and the movable part 2 is held horizontally. A metal arm 6 is attached and fixed to the movable part 2. FIG. 2b shows the piezoelectric body 3
1 and 32 are shown when voltage is applied. The piezoelectric bodies 31 and 32 expand according to the applied voltage, and the movable part 2
A couple acts on , causing a displacement of an angle θ. The arm 6 is for making the displacement of the angle θ caused in the movable part 2 into an expanded distance displacement. At this time,
Since one end of the piezoelectric bodies 31 and 32 fixed to the movable part 2 moves with the displacement of the movable part 2, the piezoelectric bodies 31 and 32 are bent. In this way,
To generate an angular displacement in the movable part 2 in response to the presence or absence of voltage application to the piezoelectric bodies 31 and 32, and to expand the angular displacement of the movable part 2 by the arm 6 to obtain reciprocating motion of the tip of the arm 6. Can be done.

However, in the conventional rocking motion generation mechanism,
As the piezoelectric body bends as the movable part moves, a considerable portion of the electrical energy supplied when applying a voltage to the piezoelectric body is consumed to bend the piezoelectric body, causing the piezoelectric body to bend. It is not possible to obtain large angular displacements. In other words, the energy spent on bending a piezoelectric body is approximately proportional to the cube of the thickness of the piezoelectric body, but if a large amount of oscillating kinetic energy is required, the volume of the piezoelectric body must be increased, and the volume of the piezoelectric body must be increased accordingly. Therefore, the thickness of the piezoelectric body must be increased, and most of the electrical energy is spent on bending the piezoelectric body. In addition, piezoelectric bodies equipped with multilayer electrodes that utilize the longitudinal effect are suitable for obtaining large displacements at low voltages, but with this structure it is difficult to reduce the thickness of the piezoelectric body, so conventional When used in a rocking motion generating mechanism, most of the electrical energy is consumed for bending. Also,
Generally, the strength of a piezoelectric body against bending stress is not very high, so when a conventional rocking motion generation mechanism repeatedly generates rocking motion, the piezoelectric body may be damaged. For the above reasons, the conventional rocking motion generation mechanism that generates large bending stress in the piezoelectric body as the piezoelectric body bends cannot be applied to devices that require large rocking motion energy. Therefore, it has the disadvantage of being subject to significant restrictions in the field of application.

An object of the present invention is to provide an efficient rocking motion generating mechanism that eliminates the above-mentioned drawbacks, does not generate large bending stress in the piezoelectric body, and consumes less energy for unnecessary displacement.

In the present invention, the mechanism of the first invention includes two piezoelectric bodies that expand and contract according to the voltage applied to each electrode to cause dimensional distortion, and one end of each of the two piezoelectric bodies is fixed. a mounting part that supports the
a first transmission part having one end fixed to one of the two piezoelectric bodies and transmitting the strain of the dimension of the piezoelectric body;
a second transmission section having one end fixed to the other one of the two piezoelectric bodies and transmitting the strain of the dimension of the piezoelectric body; and a second transmission section to a predetermined location via the first and second transmission sections. and a movable part that generates a displacement of the inclination angle in response to the transmitted distortion of the dimensions of the two piezoelectric bodies.

Further, the mechanism of the second invention includes two piezoelectric bodies that expand and contract according to the voltage applied to each electrode to cause dimensional distortion, and one end of which is fixed to one of the two piezoelectric bodies. a first transmission section that transmits the strain of the dimension of the piezoelectric body; a second transmission section that has one end fixed to the other one of the two piezoelectric bodies and transmits the strain of the dimension of the piezoelectric body; a first support part having one end fixed to one of the two piezoelectric bodies and supporting the piezoelectric body; and a second support part having one end fixed to the other one of the two piezoelectric bodies and supporting the piezoelectric body. a support part, a movable part that causes a displacement of the inclination angle by receiving the distortion of the dimensions of the two piezoelectric bodies transmitted to a predetermined location via the first and second transmission parts; a third support part that is fixed to a predetermined part of the movable part and supports the movable part; and a mounting part that fixes and supports the ends of the first, second, and third support parts. We are prepared.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 3 is a perspective view showing a first embodiment of the first invention. Two piezoelectric bodies 31 and 32 are mounted on the mounting surface of the mounting portion 11 made of metal or plastic.
Each end of is fixed. Piezoelectric body 31
and 32, one ends of the first and second transmission parts 41 and 42 are fixed respectively, and the other ends of the first and second transmission parts 41 and 42 are fixed to the other ends of the movable part 21 and 32, respectively. is fixed to one side of the The piezoelectric bodies 31 and 32 are both made of a piezoelectric material, and are electrically polarized in a predetermined direction between a pair of electrodes 71 and 72 provided on two opposing sides of each piezoelectric body. When a voltage in the same (or opposite) direction as the polarization is applied to the pair of electrodes 71 (or 72) through the conductor wire 81 (or 82), the piezoelectric body 31 (or 32) expands (or contracts) and causes dimensional distortion. arise. The movable part 21 and the first and second transmission parts 41 and 42 are plates made of metal or plastic, respectively. The plate surfaces of the first and second transmitting parts 41 and 42 are substantially parallel to each other, and the plate surface of the movable part 21 is held substantially parallel to the mounting surface of the mounting part 11. Figures 4a and b show the third
FIG. 3 is a side view illustrating the operation of the mechanism shown in the figure. Figure a
2 shows a state in which no voltage is applied to the piezoelectric bodies 31 and 32 and the movable part 21 is held parallel to the mounting surface of the mounting part 11. FIG. 4b shows that a voltage in the same direction as the polarization is applied to the piezoelectric body 31, and a voltage in the opposite direction to the polarization is applied to the piezoelectric body 32, and in response, the piezoelectric body 31 moves in the direction of arrow A. This shows the piezoelectric body 32 extending in the direction of arrow B and contracting in the direction of arrow B. The dimensional distortion occurring in the piezoelectric bodies 31 and 32 is transmitted to the movable part 21 almost along the plate surfaces of the first and second transmission parts 41 and 42, respectively, and A rotational moment is generated around an axis parallel to the plate surface of 42. This rotational moment causes an angular displacement in the movable part 21, and along with this, the first and second
Since the transmission parts 41 and 42 are bent, the bending stress generated in the piezoelectric bodies 31 and 32 can be reduced compared to the conventional one. Furthermore, compared to the case where the piezoelectric body is bent in a conventional mechanism, the first and second transmission sections 41 and 42 have a smaller plate thickness, so that less energy is consumed for bending. The movable part 2 is similar to the case shown in Fig. 2a and b.
By attaching and fixing an arm to 1, it is possible to obtain a reciprocating motion of the tip of the arm that magnifies the angular displacement generated in the movable portion 21. Although FIG. 4b shows a case where the piezoelectric body 31 is expanded and the piezoelectric body 32 is contracted, if the directions of the voltages applied to the piezoelectric bodies 31 and 32 are reversed, the piezoelectric body 31 is contracted and the piezoelectric body 32 is compressed. Since the body 32 extends and causes an angular displacement in the opposite direction to the movable part 21, a swinging motion in both directions can be obtained by changing the polarity of the applied voltage, and therefore a large angular displacement can be obtained. . Further, since a rotational moment acts on the movable portion 21 via the plate-shaped first and second transmission portions 41 and 42, the movable portion 21 performs a stable rocking motion with little lateral vibration. Furthermore, the mounting portion 11 has a simple structure and is easy to manufacture.

FIG. 5 is a perspective view showing a second embodiment of the first invention. The difference between this embodiment and the first embodiment shown in FIG. is fixed, and one end of the piezoelectric body 32 is fixed to the other mounting surface, and one end of the first transmitting part 41 is fixed to one surface of the movable part 22, and the second transmitting part 42 is fixed to the other surface of the movable part 22. One end of the is fixed. Therefore, by applying a voltage in the direction in which the piezoelectric bodies 31 and 32 extend together or in the direction in which they contract together, swinging motion in both directions can be obtained. In this mechanism,
Since the distance between the first and second transmission sections 41 and 42 can be reduced, it is easy to increase the angular displacement that occurs in the movable section 22. Note that as the material of the piezoelectric bodies 31 and 32, an electrostrictive material instead of a piezoelectric material subjected to polarization treatment can be used. In this case, when a voltage is applied to the piezoelectric bodies 31 and 32, the piezoelectric bodies 31 and 32 expand depending on the polarity. Therefore, although only a unidirectional rocking motion can be obtained, there is an advantage that there is little hysteresis in the relationship between the applied voltage and the resulting dimensional distortion.

FIG. 6 is a perspective view showing the first embodiment of the second invention. The mounting part 13 made of metal or plastic has first and second mounting surfaces, and the first
One end of each of the first and second supporting parts 63 and 64 is fixed to the mounting surface, and an end of the third supporting part 53 is fixed to the second mounting surface. The other ends of the first and second support parts 63 and 64 are fixed to one ends of the piezoelectric bodies 31 and 32, respectively, and the other ends of the piezoelectric bodies 31 and 32 are provided with first and second transmission parts, respectively. One ends of 43 and 44 are fixed. 1st and 2nd
The other ends of the transmission parts 43 and 44 are both fixed to predetermined locations on one plate surface of the movable part 23, and a third support part 5 is attached to the end of the movable part 23.
3 ends are fixed. The movable part 23, the first and second transmission parts 43, 44, and the first, second and third support parts 63, 64 and 53 are all plates made of metal or plastic. The plate surfaces of the first and second transmission parts 43 and 44 are parallel to each other and in the same direction as the plate surfaces of the first and second support parts 63 and 64. The movable part 23 is
The first and second transmitting parts 43, 4 are arranged so that the plate surfaces thereof are substantially parallel to the first mounting surface of the mounting part 13.
4 and a third support portion 53 . The piezoelectric bodies 31 and 32 are both made of piezoelectric material and are electrically polarized, and a voltage in the same (or opposite) direction as the polarization is applied to the conductor 81.
(or 82) to the pair of electrodes 71 (or 72), the piezoelectric body 31 (or 32) expands (or contracts), causing dimensional distortion. 7a and 7b are side views illustrating the operation of the mechanism of FIG. 6. FIG. FIG. 5A shows a state in which no voltage is applied to the piezoelectric bodies 31 and 32 and the movable part 23 is held parallel to the first mounting surface of the mounting part 13. FIG. 7b shows that a voltage in the same direction as the polarization is applied to the piezoelectric body 31, and a voltage in the opposite direction to the polarization is applied to the piezoelectric body 32, and in response, the piezoelectric body 31 moves in the direction of arrow C. This shows a state in which the piezoelectric body 32 is expanded and contracted in the direction of arrow D. Distortion in the dimensions of the piezoelectric bodies 31 and 32 is transmitted to the movable part 23 almost along the plate surfaces of the first and second transmission parts 43 and 44, respectively.
and 44 to produce a rotational moment about an axis parallel to the plane of the plate. This rotational moment causes an angular displacement in the movable part 23, and along with this, the first and second transmission parts 43 and 44, the first, second and third support parts 63, 64 and 5
Since the piezoelectric bodies 31 and 32 are bent, the bending stress generated in the piezoelectric bodies 31 and 32 can be reduced compared to the conventional piezoelectric bodies 31 and 32. Also, compared to the case where the piezoelectric body is bent in the conventional mechanism, the first and second transmission parts 43 and 44,
Since the first, second, and third support portions 63, 64, and 53 have small thicknesses, less energy is consumed for bending. By changing the polarity of the applied voltage, a rocking motion in the opposite direction can be obtained, so a large angular displacement can be obtained.

In the mechanism shown in FIG. 6, compared to the mechanism shown in FIG. 3, as the piezoelectric bodies 31 and 32 expand and contract, the first and second transmitting parts 43,
44 and the first and second support parts 63 and 64 transmit the swinging force to the movable part 23 while bending, the bending stress generated in the piezoelectric bodies 31 and 32 can be further reduced. Further, since the end portion of the movable portion 23 is supported by the plate-shaped third support portion 53, stable rocking motion with little horizontal shaking can be obtained.

FIG. 8 is a perspective view showing a second embodiment of the second invention. The difference between this embodiment and the first embodiment shown in FIG.
One end of the is fixed. Mounting part 14
The ends of the first and second support parts 65 and 66 and one end of the third support part 54 are fixed to the. Therefore, by applying a voltage in the direction in which the piezoelectric bodies 31 and 32 extend together or in the direction in which they contract together, swinging motion in both directions can be obtained. In this mechanism, as with the mechanism shown in FIG. 6, the bending stress generated in the piezoelectric bodies 31 and 32 can be reduced, and stable rocking motion with little lateral vibration can be obtained. Note that a piezoelectric body made of an electrostrictive material can also be used, which allows operation with less hysteresis.

FIGS. 9a to 9c are perspective views illustrating embodiments of the plate-shaped transmission section and support section used in the first and second inventions. First and second transmission parts 41 to 44 of the mechanism shown in Figures 3, 5, 6 and 8
and the first and second parts of the mechanism shown in Figures 6 and 8.
and third support parts 63-66 and 53-54
are metal or plastic plates, respectively, which bend as the piezoelectric bodies 31 and 32 expand and contract, causing angular displacement in the movable parts 21-24. In order to further reduce the energy consumed for bending at this time, it is possible to reduce the plate thickness of these transmitting parts and supporting parts, but if the plate thickness is made too small, the piezoelectric bodies 31 and 32 will be disconnected from the movable part 2.
It becomes difficult to transmit the dimensional distortion to 1 to 24.
The transmission section and support section shown in FIGS. 9a to 9c are intended to solve these difficulties. Figures a and b show grooves that are parallel to the end faces that are fixed to the movable part or the mounting part on one and both surfaces of the transmission part and the support part, respectively, to form a part with a small thickness. It is something. Figure c
The transmission part and the support part are formed by joining two thin plates to each other to form a transmitting part and a supporting part, each of which has a small part of the plate thickness. These transmission parts and support parts are manufactured by molding, cutting, or welding using metal or plastic. If high mechanical strength is required, the material may be fabricated using fiber-reinforced metal or fiber-reinforced plastic. By using such a transmission part and support part, in the mechanism of the present invention, less energy is consumed in bending the transmission part and support part, and dimensional distortion is transmitted from the piezoelectric body to the movable part to achieve good operation. You can make it happen.

FIGS. 10a and 10b are perspective views showing embodiments of piezoelectric bodies 31 and 32 used in the first and second inventions. Both of the piezoelectric bodies 31 shown in a and b of the figure are provided with a plurality of electrodes 91 and 92 arranged alternately inside each other, with the electrode 91 being placed on one of the pair of electrodes 71, and the electrode 92 being placed on one of the pair of electrodes 71. It is connected to the other end. Figure a shows a case where a piezoelectric material such as lead zirconium titanate is used as the material. a predetermined direction between the electrodes 91 and 92;
For example, polarization treatment in the direction of arrow R is performed. By applying a voltage in the same (or opposite) direction as the polarization direction between the electrodes 91 and 92 via the pair of electrodes 71, the piezoelectric body 31 undergoes dimensional distortion in the direction of arrow P (or Q). will occur. Therefore, by changing the polarity of the applied voltage, it is possible to obtain distortion in dimensions in both directions. FIG. 10b shows a case where an electrostrictive material such as magnesium lead niobate is used as the material. In this case, when voltage is applied between electrodes 91 and 92, dimensional distortion occurs in the direction of arrow S regardless of its direction. When an electrostrictive material is used, it has the advantage of having little hysteresis. By providing a multilayer electrode in which a plurality of electrodes 91 and 92 are arranged alternately as described above,
A large dimensional strain can be caused in the piezoelectric bodies 31 and 32 with a low applied voltage. Since the mechanism of the present invention hardly bends the piezoelectric bodies 31 and 32 during its operation, a swinging motion of a larger angle than before can be obtained using the longitudinal effect type piezoelectric body provided with the above-mentioned multilayer electrodes.

11 to 13 are side views illustrating the structures of the movable part, the transmission part, and the support part used in the first and second inventions. As exemplified in each of the above embodiments, the first and second transmission parts include a part that transmits strain in one dimension of the two piezoelectric bodies to the movable part;
and a part that transmits the strain of the other dimension of the piezoelectric body to the movable part. When these two parts of the first and second transmission parts, the movable part, and the first and second support parts are made of the same material, two to four of them may be made of an integral structure. Can be manufactured. 11 shows a structure in which the first and second transmission parts 41 and 42 of the mechanism shown in FIG. 3 are integrated into a first and second transmission part 45 and 46, and FIG. The movable part 21 of the mechanism and the first and second transmitting parts 41 and 42 are integrated to form the movable part 25 and the first and second transmitting parts 47 and 48, and FIG. 13 is similar to that of FIG. First and second transmission parts 43 and 44 and third support part 53 of the mechanism are shown integrated into first and second transmission parts 49 and 40 and third support part 55. According to the structure in which a plurality of transmission parts or movable parts are integrated in this way, it is possible to reduce the effort required to assemble the mechanism of the present invention.

As explained above, according to the present invention, the bending stress generated in the piezoelectric body is reduced by providing a transmission part that generates a rotational moment to the movable part while bending in response to the dimensional distortion occurring in the piezoelectric body. It is possible to realize an efficient rocking motion generating mechanism that can obtain a larger rocking angle and consumes less energy due to unnecessary displacement.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 a, b are a perspective view and a side view showing a conventional rocking motion generating mechanism, respectively, and Fig. 3
Figures 5, 6, 8, 9 a to 9 c, and 10 a, b are perspective views showing embodiments of the present invention, Figure 4 a, b, and Figure 7 a, respectively. , b, 11th
Figures 1 to 13 are side views showing embodiments of the present invention. 1, 11-14...Mounting part, 2, 21-25...
...Movable part, 31, 32...Piezoelectric body, 40-49...
...first and second transmission parts, 53-55...third
Supporting parts, 63-66...First and second supporting parts, 7, 71, 72, 91, 92... Electrodes, 8
1,82... Conductor.

Claims (1)

[Scope of Claims] 1. Two piezoelectric bodies that expand and contract in response to voltages applied to their respective electrodes to cause dimensional distortion;
a mounting part that fixes and supports one end of each of the two piezoelectric bodies; a first transmission part that has one end fixed to one of the two piezoelectric bodies and transmits the strain of the dimension of the piezoelectric body; a second transmission section that is fixed to the other one of the two piezoelectric bodies and transmits the strain of the dimension of the piezoelectric body, and the strain is transmitted to a predetermined location via the first and second transmission sections. a movable part that generates a displacement in an inclination angle in response to distortion of the dimensions of the two piezoelectric bodies. 2. The first and second transmission parts each have a plate shape, the plate surfaces of the first and second transmission parts are substantially parallel to each other, and the distortions of the dimensions of the two piezoelectric bodies are respectively Transmitted to the movable part substantially along the plate surfaces of the first and second transmission parts to generate a rotational moment around an axis substantially parallel to the plate surfaces of the first and second transmission parts. A rocking motion generating mechanism according to claim 1, wherein the rocking motion generating mechanism is configured as follows. 3. The rocking motion generating mechanism according to claim 2, wherein the first and second transmission portions are formed by providing portions with different plate thicknesses. 4. The two piezoelectric bodies each include a portion made of a piezoelectric material in which a plurality of electrodes are arranged approximately parallel to each other at predetermined intervals, and the electrodes are arranged in a predetermined direction between the plurality of electrodes. The rocking motion generating mechanism according to claim 1, which is subjected to polarization treatment. 5. The oscillation according to claim 1, wherein each of the two piezoelectric bodies includes a portion made of an electrostrictive material in which a plurality of electrodes are alternately arranged substantially parallel to each other at predetermined intervals. Movement generation mechanism. 6. The rocking motion generating mechanism according to claim 1, wherein at least any two of the first and second transmission parts and the movable part are integrally formed. 7 Two piezoelectric bodies that expand and contract according to the voltage applied to each electrode to cause dimensional distortion, and one end of which is fixed to one of the two piezoelectric bodies to transmit the dimensional distortion of the piezoelectric body. a first transmitting section having one end fixed to the other one of the two piezoelectric bodies and transmitting the strain of the dimension of the piezoelectric body; a first support part fixed to one of the two piezoelectric bodies and supporting the piezoelectric body; a second support part having one end fixed to the other one of the two piezoelectric bodies and supporting the piezoelectric body; a movable part that causes a displacement of the inclination angle by receiving the distortion of the dimensions of the two piezoelectric bodies transmitted to a predetermined location via a second transmission part; A rocking device comprising: a third support part that is fixed and supports the movable part; and a mounting part that fixes and supports the ends of the first, second, and third support parts. Movement generation mechanism. 8. The first and second transmission parts, the first and second support parts, and the third support part each have a plate shape, and the plate surfaces of the first and second transmission parts are substantially parallel to each other. parallel to each other, the plate surfaces of the first and second transmission parts and the plate surfaces of the first and second support parts are in the same direction, and the plate surface of the third support part is parallel to the first transmission part. and substantially perpendicular to the plate surface of the second transmission section, and the distortion of the dimensions of the two piezoelectric bodies is directed approximately along the plate surface of the first and second transmission sections, respectively, to the movable section. 8. The rocking motion generating mechanism according to claim 7, wherein the rotational moment is transmitted around an axis substantially parallel to the plate surfaces of the first and second transmitting portions. 9. Claim 8, wherein the first and second transmission portions, the first and second support portions, and the third support portion are formed by providing portions with different plate thicknesses.
The rocking motion generating mechanism described in . 10 The two piezoelectric bodies each include a portion made of a piezoelectric material in which a plurality of electrodes are alternately arranged substantially parallel to each other at predetermined intervals, and the electrodes are arranged in a predetermined direction between the plurality of electrodes. The rocking motion generating mechanism according to claim 7, which is subjected to polarization treatment. 11. The oscillation according to claim 7, wherein each of the two piezoelectric bodies includes a portion made of an electrostrictive material in which a plurality of electrodes are alternately arranged substantially parallel to each other at predetermined intervals. Movement generation mechanism. 12. The rocking motion generating mechanism according to claim 7, wherein at least any two of the first and second transmission parts, the third support part, and the movable part are integrally formed. .