JPH10174463A - Vibrating actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the decline of a drive efficiency and the shrinkage of a life by bringing a vibrator and a relative movement member into contact with each other through a sliding member, for adjusting a sliding resistor and constituting the sliding member with a plurality of sliding materials of different drive characteristics. SOLUTION: An ultrasonic actuator 1 is provided with a rectangular and flat elastic body 2 and a vibrator 4 constituted of piezoelectric bodies 3a, 3b for generating vibration attached to one flat face of the elastic body 2. A sliding member 5 is constituted of two sliding members 5a, 5b of different materials, and a sliding member 6 consists of two sliding members 6a, 6b of different materials. The sliding members 5a and 6a are made of the same material, and the sliding members 5b and 6b are made of the same material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration actuator, and more particularly, to a vibration actuator including a vibrator and a relative motion member that generates a relative motion by pressurizing and contacting the vibrator.

[0002]

2. Description of the Related Art Conventionally, a driving voltage is applied to a vibrator constituted by an elastic body and an electromechanical transducer mounted on the elastic body to generate a first vibration and a second vibration harmoniously.
2. Description of the Related Art A vibration actuator that generates relative motion between a relative motion member that presses and contacts a vibrator by generating an elliptical motion on a surface of the vibrator is known.

[0003] As such a vibration actuator,
For example, "Piezoelectric linear motor for optical pickup movement" (Mr. Yoshiro Tomikawa et al .: Proceedings of the 5th Dynamic Symposium on Electromagnetic Force, pp. 393-398)
Page), the results of the analysis on the configuration and load characteristics are described in detail.

Also, a new ultrasonic motor (co-authored by Mr. Sadayuki Ueba and Mr. Yoshiro Tomikawa, published by Trikeps, pages 145 to 146)
Page) discloses a self-propelled device using the vibration actuator.

FIG. 7 shows such a vibration actuator 1.
It is a front view which shows the structure of an example of 00. Thin plate-like piezoelectric members 102a and 102b made of PZT (lead zirconate titanate) are attached to one flat surface of the rectangular plate-like elastic member 101 by bonding. The piezoelectric bodies 102a and 102b
The drive voltage is applied to each of the elastic members 10.
First, a fourth-order bending vibration in the longitudinal direction and a first-order longitudinal vibration expanding and contracting in the longitudinal direction are generated.

On the other flat surface of the elastic body 101, two antinode positions in the generated fourth-order bending vibration function as driving force extracting portions 101a and 101b. An elliptical motion, which is a combined vibration of the bending vibration and the longitudinal vibration generated in the elastic body 101, is generated in the driving force extracting portions 101a and 101b.

[0007] These driving force take-out portions 101a, 101b
In order to make the sliding resistance with the contacting relative movement member (not shown) appropriate, the rectangular thin plate-shaped sliding member 104a,
104b is attached and mounted. Such sliding material 1
As the materials 04a and 104b, a material such as a PTFE-based resin is usually used.

In the example shown in FIG. 7, a vibrator 103 is constituted by the elastic body 101 and the piezoelectric bodies 102a and 102b. In this vibration actuator 100, the elastic body 101
Are designed so that the natural frequencies of the fourth-order bending vibration and the first-order longitudinal vibration that occur in the first and second longitudinal vibrations are very close to each other.
Therefore, the two vibrations can be generated in a harmonious state by applying two phases of AC voltages having frequencies close to the respective natural frequencies.

[0009] A combined vibration of the two generated vibrations is generated as elliptical vibrations in the driving force take-out portions 101a and 101b, and the elliptical vibration causes a relative motion between the relative motion members contacting the sliding members 104a and 104b. Produces relative motion. Thus, the sliding members 104a and 104b are interposed in the contact between the vibrator 103 and the relative motion member.

[0010]

The driving characteristics (such as wear resistance and relative motion transmission characteristics) of these sliding members 104a and 104b are determined mainly by the type of resin used. Therefore, the sliding members 104a, 104
The drive characteristics of b are in accordance with the characteristics specific to the resin type, and even if the resin type is changed, only discontinuous drive characteristics can be obtained.

Therefore, when the desired driving characteristic is located in the middle of the driving characteristic determined by the resin type, it is possible to obtain an approximate driving characteristic, but not to obtain a completely matched driving characteristic. could not.

For this reason, depending on the specifications of the vibration actuator, there is a problem that the drive efficiency is reduced and the life is reduced due to the characteristics of the resin used for the sliding member.

[0013]

According to a first aspect of the present invention, there is provided a vibrator for generating vibration, and a relative motion member for performing relative motion between the vibrator and the vibrator in contact with the vibrator in a pressurized state. Wherein the vibrator and the relative motion member are in contact with each other via a sliding member that adjusts sliding resistance, and the sliding member is constituted by a plurality of sliding members having different driving characteristics. It is characterized by that.

According to a second aspect of the present invention, in the vibration actuator according to the first aspect, the plurality of sliding members are linearly mounted in a width direction of the vibrator when the vibrator has a rectangular flat plate shape. When the vibrator has a cylindrical or tubular shape, the vibrator is mounted on the end face of the vibrator in a fan shape.

[0015] The invention of claim 3 is claim 1 or claim 2.
In the vibration actuator described in (1), a plurality of sliding members are arranged at symmetrical positions.

According to a fourth aspect of the present invention, there is provided the first to third aspects.
In the vibration actuator described in any one of the above, the sliding member is fitted and bonded to a fitting portion provided on the vibrator, and is mounted.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a vibration actuator according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of each embodiment, an ultrasonic actuator that uses vibration in an ultrasonic region is used as an example of a vibration actuator.

FIG. 1 is a perspective view showing the configuration of the ultrasonic actuator 1 according to the first embodiment. The ultrasonic actuator 1 of the present embodiment includes a rectangular flat elastic body 2 and vibration-generating piezoelectric bodies 3 a and 3 attached to one plane of the elastic body 2.
b.

The vibrator 4 has an elastic body 101 shown in FIG.
Since the basic structure is the same as that of the first embodiment, description of common parts will be omitted as appropriate. In the other plane of the elastic body 2, two grooves 2a and 2b having the same rectangular cross section in the elastic body width direction are provided.
Is provided. The sliding members 5, 6 are bonded to the grooves 2a, 2b in a state where they are fitted. Since the sliding members 5 and 6 are fitted and adhered, the mounting strength is improved.

The sliding member 5 includes two sliding members 5 made of different materials.
a, 5b. On the other hand, the sliding member 6 is composed of two sliding members 6a and 6b having different materials. The sliding members 5a and 6a are made of the same material.
b and 6b are made of the same material. Each sliding material 5a
6b are provided at positions symmetrical with respect to the center of the sliding member mounting surface of the elastic body 2.

In the present embodiment, the sliding members 5a, 5b and the sliding members 6a, 6b are mounted so as to minimize the gaps, but may be mounted so as to form the gaps. . Further, the sliding members 5a to 6b are arranged for the entire length in the elastic body width direction. In the present embodiment, the sliding members 5a and 6a are made of a PTFE-based resin.
a and 6b were made of a wholly aromatic polyimide resin.

FIG. 2 shows the relative motion speed between the vibrator 4 and the relative motion member and the motion load between the vibrator 4 and the relative motion member when the sliding members 5 and 6 are made of only PTFE resin. FIG. 3 is a graph showing the relationship (driving characteristics) of FIG.
5 is a graph showing driving characteristics when the sliding members 5 and 6 are made of a wholly aromatic polyimide resin alone. FIG. 4 is a graph showing drive characteristics in the present embodiment.

As in the prior art, the sliding members 5 and 6 are made of a single resin material (PTFE resin or wholly aromatic polyimide resin).
In the case of the above configuration, as shown in FIG. 2 or FIG. 3, only the unique driving characteristics of the materials used for the sliding members 5 and 6 were obtained.

On the other hand, according to the present invention, FIGS.
Driving characteristics located between the driving characteristics shown in FIG. That is, by changing the combinations and ratios of the materials constituting the sliding members 5 and 6, a sliding member having desired driving characteristics can be obtained.

(Second Embodiment) FIG. 5 is a perspective view showing a configuration of an ultrasonic actuator 1-1 according to a second embodiment. The ultrasonic actuator 1-1 according to the present embodiment
Since the basic configuration is almost the same as that of the ultrasonic actuator 1 according to the first embodiment, the same portions are denoted by the same reference numerals in the drawings, and redundant description will be omitted as appropriate.

The ultrasonic actuator 1-1 of the present embodiment
Are different from the ultrasonic actuator 1 of the first embodiment in the shape of the sliding member and the arrangement of the sliding member on the elastic body 2.

That is, the sliding member 5a-
Round holes 7a, 7b, 8a and 8b are provided on mounting surfaces of the sliding members 6a-1 and 6b-1 and the sliding members 6a-1 and 6b-1,
Sliding members 5a-1 to 6b-1 are inserted into these round holes 7a to 8b.
Are bonded in a state where they are fitted.

The round holes 7a to 8b are mounted at symmetrical positions with respect to the center of the sliding member mounting surface of the elastic body 2. The sliding members 5a-1 and 6a-1 are made of the same material,
-1 and 6b-1 are made of the same material. The other configuration is exactly the same as the ultrasonic actuator 1 of the first embodiment.

As a result, the ultrasonic actuator 1-1 of the present embodiment has exactly the same effects as the ultrasonic actuator 1 of the first embodiment, and has a greater effect on the vibrator 4 and the relative motion member than the first embodiment. Since the contact area with the contact is reduced, the sliding resistance is further reduced, and different driving characteristics can be obtained.

(Third Embodiment) FIGS. 6A to 6C
6A and 6B are explanatory diagrams showing the arrangement of sliding members in the ultrasonic actuator according to the third embodiment, and FIGS.
The broken lines m and n in FIG. 6C indicate sliding members 1 in the conventional ultrasonic actuator 100 shown in FIG.
The center position (antinode position of the fourth-order bending vibration generated in the elastic body 2) of the attaching position of 04a, 104b is shown.

The ultrasonic actuator 1 shown in FIG.
-2 indicates two types of sliding members 9 on the sliding member mounting surface of the elastic body 2.
a and 9b are mounted in two sets centering on two broken lines m and n. Further, the two sets of sliding members 9a and 9b are arranged symmetrically with respect to the center O of the sliding member mounting surface of the elastic body 2 and without any gap therebetween.

The ultrasonic actuator 1 shown in FIG.
In the case of -2, two sliding members 9b are mounted on the inner side in the longitudinal direction of the elastic body 2 and two sliding members 9a are mounted on the outer side.

Next, an ultrasonic actuator 1-3 shown in FIG. 6 (b) uses two sets of sliding members 10a and 10b having a shorter overall length than the sliding members 9a and 9b shown in FIG. 6 (a). Dashed line m,
It is arranged at a position symmetrical with respect to the centers O ₁ and O _{2 of} n.

Therefore, the four sliding members 10a and 10b arranged near the broken lines m and n are located at the center O of the broken lines m and n.
₁ and O ₂ , and all eight sliding members 10 a and 10 b are symmetrically arranged with respect to the center O of the elastic body 2. As a result, the difference between the left and right behaviors when the ultrasonic actuator 1-3 reciprocates is remarkably improved.

Further, in the ultrasonic actuator 1-4 shown in FIG. 6 (c), three rectangular planar sliding members 11a and 11b are alternately arranged on the broken lines m and n, respectively.
Are placed. The sliding members 11a and 11b on the broken line m and the sliding members 11a and 11b on the broken line n
Are arranged symmetrically with respect to the center.

The ultrasonic actuator 1 shown in FIG.
In -4, two kinds of sliding members 11a and 11b are alternately arranged. However, when three or more kinds of sliding members are used in combination, the arrangement of the sliding members 11a and 11b shown in FIG. According to this, the left-right difference can be easily eliminated, which is desirable.

(Modification) In the description of each embodiment described above in detail, the ultrasonic actuator is used as the vibration actuator. However, the present invention is not limited to such an embodiment, and other vibration regions may be used. The same applies to vibration actuators utilizing

In each of the embodiments, the piezoelectric element is used as the electromechanical transducer. However, the vibration actuator according to the present invention is not limited to such an embodiment.
For example, the present invention can be applied to an electrostrictive element other than the piezoelectric element.

In the description of each embodiment, a vibration actuator using a vibrator that generates longitudinal vibration and bending vibration on a rectangular plate-like elastic body is used. The vibration actuator according to the present invention has such an aspect. However, the present invention is not limited to this.

For example, a piezoelectric element for generating longitudinal vibration and a piezoelectric element for generating torsional vibration are mounted on a cylindrical elastic body, and an elliptical vibration which is a combination of these vibrations is generated on the end face of the elastic body. The same applies to a vibration actuator that drives a relative movement member by pressing a relative movement member (moving element) in the form of a pressurized cylinder against the end face.

In this case, two or more types of sliding members having different materials may be formed into a fan shape, and the sliding members may be stuck to the end face of the elastic body in a ring shape.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of an ultrasonic actuator according to a first embodiment.

FIG. 2 shows a relationship between a relative movement speed and a movement load when the sliding member is made of only PTFE resin (drive characteristics).
FIG.

FIG. 3 is a graph showing driving characteristics when a sliding member is formed only of a wholly aromatic polyimide resin.

FIG. 4 is a graph showing drive characteristics according to the first embodiment.

FIG. 5 is a perspective view illustrating a configuration of an ultrasonic actuator according to a second embodiment.

FIGS. 6 (a) to 6 (c) are explanatory views showing the arrangement of sliding members in the ultrasonic actuator according to the third embodiment.

FIG. 7 is a front view showing a configuration of an example of a conventional vibration actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic actuator 2 Elastic body 2a, 2b Groove part 3a, 3b Vibration generating piezoelectric body 4 Vibrator 5, 6 Sliding material 5a, 5b, 6a, 6b Sliding material

Claims (4)

[Claims] 1. A vibration actuator comprising: a vibrator that generates vibration; and a relative motion member that makes a relative motion between the vibrator and the vibrator by contacting the vibrator in a pressurized state; A vibrating actuator, wherein the armature and the relative motion member are in contact with each other via a sliding member for adjusting sliding resistance, and the sliding member is constituted by a plurality of sliding members having different driving characteristics. . 2. The vibration actuator according to claim 1, wherein the plurality of sliding members are linearly mounted in a width direction of the vibrator when the vibrator has a rectangular flat plate shape. When the vibrator has a cylindrical shape or a tubular shape, the vibrator is mounted in a fan shape on an end face of the vibrator. 3. The vibration actuator according to claim 1, wherein the plurality of sliding members are arranged at symmetric positions. 4. One of claims 1 to 3
In the vibration actuator described in the paragraph, the sliding member is fitted to and bonded to a fitting portion provided on the vibrator.