JPH04117178A - Ultrasonic wave motor - Google Patents

Abstract

PURPOSE:To support a stator and a moving element by small-sized supports without loss of vibrating characteristic of an elastic element and driving characteristics of the moving element, and to reduce in size them by supporting flanges provided at the stator and the moving element by a support of a material having low longitudinal elastic coefficient. CONSTITUTION:In a stator 1, a piezoelectric element 12 is integrally adhered to an elastic element 11 made of phosphorus bronze, stainless steel, Invar, etc., and an annular flange 11a is integrally molded in the vicinity of the central plane of the inner periphery of the element 11. Supports 3, 4 respectively support the stator 1 and a moving element 2, and in contact with the inner peripheral surfaces of flanges 11a, 21a of the element 11 and the a moving element base material 21 to be supported axially. The supports 3, 4 are formed of materials having small longitudinal elastic coefficient. Accordingly, the diameters of the elements 11, 2 can be formed substantially in the same diameters as those of the supports 3, 4. Thus, the vibrating characteristic of the element 11 and the driving efficiency of the moving element can be improved, and the entirety can be reduced in size.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ultrasonic motor that generates progressive vibration waves in a surface fixed plate and drives a moving element that is brought into pressurized contact with the surface fixed plate. This invention relates to an ultrasonic motor with an improved support structure.

[Conventional Technique] Conventionally, in this type of ultrasonic motor, a large number of elastic bodies of a surface stator and movable elements (rotor) were arranged in the radial direction on the outer periphery near their neutral plane. It was supported by a fixed cylinder via a rod-shaped support part.

By supporting the elastic body with this support part, an attempt was made to improve the vibration characteristics of the elastic body and the drive efficiency of the mover.

[Problems to be Solved by the Invention] However, in the conventional ultrasonic motor described above, the elastic body and the support portion of the mover are completely fixed to the fixed cylinder.
Moreover, since the support part is integrally molded with the elastic body and the slider, which are made of a metal material, a support part having a large elastic modulus has been used.

Therefore, the elastic body and the slider are susceptible to mechanical constraints, and in order to improve the vibration characteristics of the elastic body and the drive efficiency of the slider, it is necessary to increase the radial length of the support part. . For this reason, the supporting body such as the fixed cylinder becomes large in the radial direction, resulting in a problem that the entire ultrasonic motor becomes large in size.

The present invention solves the above-mentioned problems of conventional ultrasonic motors, allows the diameters of the elastic body and mover to be approximately the same as the diameters of the support body, and improves the vibration characteristics of the elastic body. It is an object of the present invention to provide an ultrasonic motor that can improve the drive efficiency of a moving element and can be made smaller as a whole.

[Failure to solve the problem]

In order to solve the above problems, an ultrasonic motor according to the present invention includes a piezoelectric body that is excited by a drive signal and an elastic body that is bonded to the piezoelectric body and that generates progressive vibration waves on the drive surface by the excitation. In an ultrasonic motor including a surface constant and a moving element that is in pressurized contact with a driving surface of the elastic body and is driven by the progressive vibration wave, the area near the neutral plane of both or one of the elastic body and the moving element. This configuration includes a flange portion provided at the flange portion and a support body made of a material having a small longitudinal elastic modulus that supports the vicinity of the root of the flange portion.

In this case, the support has a Rockwell hardness of HRR1
15 or less, longitudinal elastic modulus E2. It can be made of soft plastic with OG P a or less.

Further, a rotation preventing portion may be provided between the flange portion and the support body.

(Function) According to the above configuration, the support body is made of a material having a small longitudinal elastic modulus;
For example, since it is made of soft plastic, even if it is supported in the axial direction near the root of the flange, the vibration characteristics of the elastic body and the drive efficiency of the slider will not be affected, and the conventional support part can be omitted.

Moreover, since it can be supported from the axial direction, the two run parts and the support body can be completely fixed just by providing a rotation preventing part.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings and the like.

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic motor according to the present invention.

The surface constant 1 is made by integrally bonding a piezoelectric body 12 to an elastic body 11 made of phosphor bronze, stainless steel, invar, etc., and has an annular flange portion 11a near the neutral plane on the inner circumferential side of the elastic body 11. are integrally molded.

The mover 2 has a slider material 22 integrally bonded to a mover base material 21, and an annular flange portion 21a is integrally formed near the neutral plane on the inner circumferential side of the mover base material 21. There is.

The support 3.4 has a surface constant 1. The elastic bodies 11 . It has a structure in which it is in contact with the flange portions 11a, 21a of the movable element base material 21 and their inner peripheral surfaces and is supported from the axial direction. Since it is supported in the axial direction in this way, the diameter of the support body 3.4 is the same as that of the surface constantr 1.4. It can be made approximately the same size as the diameter of the mover 2.

These supports 3 and 4 are made of a soft plastic such as polypropylene, polyethylene, polyamide, fluorine resin, styrene resin, methylpentene resin, etc., and have sufficient mechanical strength and sufficient strength in the amplitude direction. Rockwell hardness HRR=115 so that it can be displaced to
In the following, a longitudinal elastic modulus B=2.0 GPa and an original 2° are preferably used.

A projection 3a is provided on the upper end surface of the support 3.
The flange portion 11a of the elastic body 11 has a cutout portion 11a.
, is provided. The rotation preventing portion 5 is formed by fitting the projection portion 3a and the notch portion 11a+.

Similarly, a protrusion 4a is provided on the lower end surface of the support body 4, and a notch 21a is provided in the flange 21a of the mover base material 21.

The protrusion 4a and the notch 21a fit together to form a rotation stopper 6.

When a drive signal (AC voltage) is applied to the piezoelectric body 12, bending vibration occurs in the piezoelectric body 12, and a progressive vibration wave is generated in the elastic body 11. This progressive vibration wave causes the moving element 2 to move to I! j! Driven by friction. At this time, the support body 34 can expand and contract because the elasticity coefficient of the support body 34 is sufficiently small by ζ.

2 to 4 show the second to fourth diagrams of the ultrasonic motor according to the present invention.
It is a figure showing a 4th example.

In each of the following embodiments, the same reference numerals are given to parts that perform the same functions as in the first embodiment described above, and the differences will be mainly explained.

In the embodiment shown in FIG. 2, the vibrating body II and the mover base material 21
Flange portions 11a, 21a are provided near the neutral plane on the outer diameter side of the flange portions 11a, 21a.
and a soft plastic support 3 in contact with its outer peripheral surface.
．． This was supported by Section 4.

Similarly, a rotation preventing portion 5.6 is provided between each support 3.4 and the flange portions 11a, 21a.

In the embodiment shown in FIG. 3, the vibrating body 11 and the mover base material 21
Franz portion 1 is placed near the neutral plane on both sides of the outer diameter and inner diameter of the
1a and 21a, and flantz parts 1 on both sides.
1a, 21a and both their inner and outer peripheries are in contact with and supported by soft plastic supports 3.4.

In this embodiment as well, detent portions 5 and 6 are similarly provided.

In the embodiment shown in FIG. 4, a plurality of through holes 11a2 are provided in the flange portion 11a as the rotation prevention portion 5, and protrusions 3a are provided in corresponding locations on the support body 3, and these through holes 11az
It is designed to fit into the

In this way, by fitting the through hole 11a2 and the protrusion 3a, sufficient joint support strength is obtained, so the process of bonding the flange part 11a and the support body 3 can be omitted, and production efficiency can be improved. I can do it.

Note that the flange portion 21a side can also have a similar configuration.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

The anti-rotation portion may have any form as long as it can be coupled by movement in the axial direction, for example, it may be a combination of a convex portion and a concave portion, and the number of detent portions provided is not limited. Also,
It is also possible to replace the support body side with a notch and the surface ruler or slider side with a protrusion.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the flange portions provided on the surface constantr and the slider are supported from the amplitude direction using a support made of a material with a low elasticity coefficient, so that the flange portions are supported. Even if this section is omitted, the vibration characteristics of the elastic body and the drive characteristics of the moving element can be supported without impairing the vibration characteristics of the elastic body and the drive characteristics of the moving element, and the ultrasonic motor can be miniaturized.

According to claim (3), since the flange portions of the surface ruler and the slider and the support body are fixed by the rotation preventing portions, sufficient bonding strength can be obtained and the conventional bonding step can be omitted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic motor according to the present invention. 2 to 4 show the second to fourth diagrams of the ultrasonic motor according to the present invention.
It is a figure showing a 4th example. I; Surface constant I■; Elastic body I2; Piezoelectric body 11a; Franz portion 2; Mover 21; Mover base material 22; Slider material 21a; Flange portion 3.4; Support body 5-stopping portion 11a+; Notch Part 3a; Protrusion 6; Rotation prevention part

Claims (3)

[Claims] (1) A surface constant having a piezoelectric body that is excited by a drive signal and an elastic body that is bonded to the piezoelectric body and that generates a progressive vibration wave on the drive surface by the excitation; , a mover driven by the progressive vibration wave; and a flange portion provided near a neutral plane of both or one of the elastic body and the mover; a root of the flange portion. An ultrasonic motor characterized by comprising: a support member made of a material having a small longitudinal elastic modulus that supports the vicinity thereof; and; (2) The ultrasonic motor according to claim 1, wherein the support is made of a soft plastic having a Rockwell hardness of HRR of 115 or less and a longitudinal elastic modulus of 2.0 GPa or less. (3) The ultrasonic motor according to claim (1), characterized in that a rotation preventing portion is provided between the flange portion and the support body.