JP2562633B2 - Piezo motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a piezoelectric motor that converts a stretching motion of a piezoelectric member into a bending motion of an elastic body to obtain a driving force.

[Prior Art] Conventionally, automatic focusing (AF) of a lens used in a camera or the like.
Since rotary motion is advantageous for the drive system in the mechanism,
An electromagnetic motor with gear reduction was used.

Furthermore, in recent years, a piezoelectric ultrasonic motor utilizing displacement of a piezoelectric body capable of direct drive without gear reduction has also appeared.

However, generally, a so-called traveling-wave piezoelectric motor is often used. In this method, the standing wave of longitudinal vibration is changed into a traveling wave, so that the structure of the piezoelectric body is complicated and the driving method thereof is also different. Was also complicated. Since this piezoelectric motor uses a piezoelectric body having a thickness of 100 μm or more, a high drive voltage is required, and it is necessary to select elements and take measures against noise, which causes a problem in the drive circuit configuration.

Further, in addition to the piezo-electric motor having a traveling waveform, there is a worm-type insect piezo-electric motor for linear movement. This motor is simple to assemble and configure. Example 5 of this piezoelectric motor
Shown in Figures (A) and (B).

FIG. 5 (A) shows a front view and FIG. 5 (B) shows a side view.

In the figure, 1 is a slider formed of three units such as metal,
Reference numeral 2 is a laminated ceramic piezoelectric material, 3a and 3b are adhesive layers, and 4 is a stator.

When a predetermined voltage is applied to the laminated ceramic piezoelectric body 2, the piezoelectric body 2 expands and contracts. Both ends of the piezoelectric body 2 are fixed to the leg portions of the slider 1 via adhesive layers 3a and 3b, and the leg portions of the slider 1 cause bending movements as the piezoelectric body 2 expands and contracts, and swings around the base portion as a fulcrum. Produces a dynamic movement.

The legs of the slider 1 have a slight difference in their lengths.
As shown in FIGS. (A) and (B), the stator 4 is only partially contacted. Therefore, when the slider is brought into pressure contact with the stator 4 with a predetermined pressure, a frictional effect of the contact portion between the stator 4 and this leg portion causes a worming movement, and the slider 1 can move in the directions of arrows A and B in the figure. Becomes

[Problems to be Solved by the Invention] However, the piezoelectric motor based on the shingling insect movement method described above is inefficient in circular movement. This is because a new guide member for making a circular motion is required, which causes friction loss with the slider 1.

Further, the strokes on the inner diameter side and the outer diameter side are the same, and the operation is not performed smoothly.

[Means for Solving Problems] The present invention has been made for the purpose of solving the above-mentioned problems, and has the following configuration as one step for solving the above-mentioned problems.

That is, in a piezoelectric motor that obtains a driving force by converting the expansion and contraction movement of the piezoelectric member into the bending movement of the elastic body, the elastic body is divided so as to generate different bending displacement with respect to the displacement of the piezoelectric member.

[Operation] In the above-described configuration, circular movement is performed with the portion having a small displacement as the inner diameter side.

Embodiment An embodiment according to the present invention will be described in detail below with reference to the drawings.

[First Embodiment] FIGS. 1A and 1B are a front view and a side view of an embodiment according to the present invention, in which 11 is a U-shaped slider and 12a.
Is a leg portion of the slider 11 which is divided into two inner diameter sides, 12b is a leg portion of the slider 11 which is divided into two outer diameter sides, 13 is a laminated ceramic piezoelectric body, and 14a and 14b fix the piezoelectric body 13 to the slider 11. The adhesive layer, 15 is a ring-shaped stator having a stepped shape with a thin outer diameter portion and a thick inner diameter portion.

As shown in FIG. 1 (B), the distance between the fixing position of the piezoelectric body 13 of the slider 11 and the tip of the leg portion is different on the outer diameter side by l1 and on the inner diameter side by l2, which has a relationship of l1> l2. . This l1 and
l2 is the radius γ1 from the center of the stator 15 to the inner leg 12a
And the above l1, which corresponds to the radius γ2 to the outer diameter side leg 12b.
Select l2 as appropriate.

In this way, the leg portion of the slider 11 is divided into two, and the length l2 from the piezoelectric body 13 on the inner diameter side to the tip of the leg portion is equal to the length l1 on the outer diameter side.
By making the length shorter, the change in the leg tip end portion of the slider 11 with respect to the base portion becomes larger on the outer diameter side than on the inner diameter side. Therefore, the movement distance on the outer diameter side becomes larger than on the inner diameter side, and as described above, the leg lengths l1 and l2 are set to the optimum values, and the slider 11 is pressed against the stator 15 so that a guide member or the like is not required. A smooth circular movement is achieved.

In addition, since the piezoelectric body 13 is of a laminated type instead of being thick as in the conventional traveling waveform, the driving voltage thereof can be significantly reduced in the case of the same mechanical output. For example, what used to require a drive voltage of 30V to 150V
It was possible to drive at a low voltage of about V-10V. Therefore, the selection of elements is advantageous, noise countermeasures are almost unnecessary, and the drive circuit can be easily manufactured.

Second Embodiment In the above description, the ring-shaped stator 15 is provided with a step to deal with the change in the length of the leg portion of the slider 11, but the present invention is not limited to this example, and it is fixed. The child 15 may have a flat structure without providing a step.

FIG. 2 shows a side view of another embodiment according to the present invention in which the stator 15 has a flat structure without a step.

As shown in FIG. 2, the surface of the ring-shaped stator 25 is substantially flat. The leg portions 22a and 22b of the slider 21 divided into two parts have the same length, and the laminated ceramic piezoelectric body 23 is arranged so that the inner leg portion 22a and the outer leg portion 22b have different positions from the tip of the leg. Tilt and stick. Therefore, the distance from the position where the piezoelectric body 23 is fixed to the tip of the leg is, for example, l2 on the inner diameter side and on the outer diameter side.
l1 and l1> l2.

Therefore, by pressing the slider 21 against the stator 25, the moving distance from the inner diameter side to the outer diameter side becomes larger as in the configuration of the first embodiment, and a smooth circular movement is performed without the need for a guide member or the like. be able to.

Third Embodiment Further, it is not limited to the above example that the piezoelectric body fixing position from the tip end portion to the slider leg portion is different between the inner diameter side and the outer diameter side. The adhesive layers fixed to the leg portions may have different configurations on the inner diameter side and the outer diameter side.

FIG. 3 (B) is a side view of the example configured as described above.

In this embodiment, the laminated ceramic piezoelectric body 33 is disposed between the leg portions 32 of the slider 31, and the bonding position between the piezoelectric body 33 and the leg portion 32 is set to the inner diameter side 32a with the auxiliary members 34 and 35 interposed. Offset from the outer diameter side 32b, the distance from the tip to the bonding position l1 and l
2 is set so that l1> l2.

The inner diameter side auxiliary members 35a, 35b are located at the tip end side positions of the legs 32a of the piezoelectric body 33, and the outer diameter side auxiliary members 34a, 34b are located at the upper base side positions of the leg portions 33b of the piezoelectric body 33. The distance from the tip (distance from the surface of the stator 36) is l2, l1. It is desirable that the auxiliary members 34, 35 are made of metal or ceramic having high tensile and compressive rigidity.

An external perspective view of this embodiment is shown in FIG. As shown, the radius γ1 from the center 0 to the inner diameter side leg portion 32b,
The above-mentioned l1 and l2 may be appropriately selected in correspondence with the radius γ2 to the outer diameter leg portion 32a.

[Fourth Embodiment] In the above description, an example in which the slider portion to which the piezoelectric body is fixed rotates on the stator has been described. However, the slider is fixed and the ring-shaped member is used as the mover. The member may be configured to rotate.

Even in this case, the driving distance is different between the inner circumference side and the outer circumference side of the ring, the driving force of the slider portion is transmitted to the mover side without waste, and the efficiency can be improved.

As described above, according to the above-described embodiment, it is possible to efficiently rotate the piezo-electric motor of the simple scale insect type. This type of piezoelectric motor is easy to assemble, and the manufacturing cost can be reduced as compared with the traveling wave type.

Further, in the above description, the shape of the stator and the mover is ring-shaped, but the shape is not limited to this, and any structure can be used as long as it can rotate. You can That is, the outer peripheral portion such as a disc shape or a cylindrical shape may be circular, and the polygonal shape may be formed as long as it has a surface corresponding to the slider leg portion. It doesn't matter.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a piezoelectric motor having a simple structure and capable of efficiently performing rotary motion.

[Brief description of drawings]

FIG. 1 (A) is a front view of the first embodiment according to the present invention, FIG. 1 (B) is a side view of the first embodiment according to the present invention, and FIG. 2 is a second embodiment of the present invention. FIG. 3 (A) is a front view of the third embodiment according to the present invention, FIG. 3 (B) is a side view of the third embodiment according to the present invention, and FIG. 4 is related to the present invention. Fig. 5 is an external perspective view of the third embodiment, Fig. 5 (A) is a front view of a conventional worm insect type piezoelectric motor, and Fig. 5 (B) is a side view of a conventional worm insect type piezoelectric motor. In the figure, 1,11,21,31 …… slider, 2,13,23,33 …… piezoelectric material, 3a, 3b, 14a, 14b …… adhesive layer, 4,15,25,36 …… stator, 12a, 22a, 32a, ... Slider inner diameter side leg, 12b, 22b, 33
b ... Legs on the outer diameter side of the slider, 34a, 34b, 35a, 35b ... Auxiliary members.

Claims (2)

(57) [Claims] 1. A piezoelectric motor for converting an expansion / contraction motion of a piezoelectric member into a bending motion of an elastic member to obtain a driving force, wherein the elastic member is divided and arranged to generate different bending displacement with respect to displacement of the piezoelectric member. A piezoelectric motor characterized in that it makes a circular motion with a portion having a small diameter as the inner diameter side. 2. The piezoelectric motor according to claim 1, wherein the piezoelectric member has a laminated structure.