JPH1056787A - Vibrating actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the driving efficiency of an ultrasonic actuator by a method wherein a pillar-shaped relative motion member is pressurized to, and brought into contact with, one edge of a vibrator, a motion transmission member is installed at the relative motion member and the propagation of a longitudinal vibration to the motion transmission member is prevented. SOLUTION: In a moving element 24 as a relative motion member, a hollow and nearly cylindrical moving-member matrix 36 is installed at an end part on the side which is at a distance from a vibrator 23, and a torus-shaped sliding material 37 is pasted on the edge on the side of the vibrator 23 of the moving- member matrix 36. In addition, a gear 38 as a motion transmission member is fitted to a small-diameter part 36a at the moving-member matrix 36, and a gap part 41 is formed between the moving-element matrix 36 and the gear 38 so that an impact stress which is generated in the moving member 24 is not propagated to the gear 38. Consequently, the impact stress which is generated in the moving member 24 is reflected by the edge on the side opposite to the sliding face of the moving-member matrix 36, and the energy of a longitudinal vibration is propagated inside the moving member 24. Thereby, the driving efficiency of an ultrasonic actuator 21 can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration actuator having a vibrator utilizing longitudinal vibration and torsional vibration.

[0002]

2. Description of the Related Art Vibration actuators characterized by small size, light weight, low speed, high torque, etc. are being put to practical use in various products such as cameras. It is becoming more active.

FIG. 10 is an explanatory view showing the structure of a vibration actuator 1 proposed by Japanese Utility Model Laid-Open No. 4-2987. As shown in FIG. 10, the vibration actuator 1 includes a vibrator (stator) 2, a head mass 5, and a mover (rotor) 10 as a relative motion member. The vibrator 2 includes a longitudinal vibrator 3 formed of a laminated piezoelectric actuator, a Langevin-type vibration-exciting piezoelectric element (torsional vibrator) 4, a head mass 5, a metal block 6, and insulators 8a and 8b. It consists of. These are penetrated and fixed by bolts 9, and are fixed to and supported by the bolts 9 by screwing the hexagonal bolts 7 on the end surface side of the metal block 6.

The movable element 10 has a built-in bearing 11
And is rotatably supported by the bolt 9 via. Further, the moving element 10 is connected to the head mass 5 via the pedestal 12 by the nut 14 and the coil spring 13 screwed to the bolt 9.
Pressed to. Further, a motion transmitting member 10 a such as a spur gear is formed integrally with the movable element 10 on the upper end surface side of the outer peripheral portion of the movable element 10. The vertical vibrator 3 is excited non-resonantly in a form that matches the resonance frequency of the vibrator 2. Also, the vibrator 2
In the operation of the transducer portion of the mechanical channel filter using the torsional vibration mode, the operation is performed in the mode due to the torsional deformation of the round bar. In addition, the momentum of the vibrator 2 is further amplified by the head mass 5. Therefore, the vibrator 2 generates a rotating force in the clockwise direction and the counterclockwise direction at the resonance frequency at the end face of the head mass 5 with which the moving element 10 contacts.

[0005] In the vibration actuator 1 shown in FIG.
In order to simplify the shape of the vibrator 2 incorporating the motion transmitting member 10a, facilitate the vibration design of the vibration actuator 1, and suppress the vibration constraint of the vibrator 2, the moving element 10
A spur gear 10a is integrally formed on the upper end surface side of the outer peripheral portion of.

[0006]

However, in the vibration actuator 1 described above, the moving element 1
A part of the energy of the longitudinal vibration transmitted to the spur gear 1
0a is absorbed by an external device that engages with Oa. Therefore, the intermittent contact between the vibrator 2 and the moving element 10 cannot be performed as designed, and there is a problem that the driving efficiency of the vibration actuator 1 is reduced.

[0007]

According to a first aspect of the present invention, a vibration actuator generates a columnar vibrator for generating longitudinal vibration in an axial direction and torsional vibration in an axial direction, and one end face of the vibrator. A relative motion member having a columnar shape that comes into pressure contact with the motor, a motion transmission member provided on the relative motion member, and a vibration prevention mechanism that prevents the longitudinal vibration from propagating to the motion transmission mechanism. And

According to a second aspect of the present invention, in the vibration actuator according to the first aspect, the vibration preventing mechanism is disposed between the relative motion member and the motion transmission member, and intersects the vibration direction of the longitudinal vibration. It has a gap provided along the direction.

According to a third aspect of the present invention, in the vibration actuator according to the first aspect, the vibration preventing mechanism is disposed between the relative motion member and the motion transmission member, and has an elastic deformation portion. It is characterized by the following.

According to a fourth aspect of the present invention, in the vibration actuator according to the third aspect, the position of the elastic deformation portion with respect to the axial direction is determined by the motion transmitting member and a driven member driven by the motion transmitting member. Are arranged inside a region in a contact state.

According to a fifth aspect of the present invention, in the vibration actuator according to the third aspect, the elastic deformation portion is coupled to the relative motion member at an end face of the motion transmission member on the vibrator side. I do.

According to a sixth aspect of the present invention, in the vibration actuator according to the third aspect, the elastic deformation portion is provided at a position substantially at the center in the axial direction of the motion transmitting member.

According to a seventh aspect of the present invention, in the vibration actuator according to the third aspect, a fixed shaft for supporting the vibrator and the relative movement member, and the fixed shaft provided on the relative movement member to fix the relative movement member. A support member for supporting the shaft, wherein the elastically deformable portion and the support member are provided at substantially the same position in the axial direction.

According to an eighth aspect of the present invention, in the vibration actuator according to the first aspect, the motion transmitting member is made of a resin material.

According to a ninth aspect of the present invention, in the vibration actuator according to the first aspect, the motion transmitting member is a gear or a cam.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Note that the description of each embodiment is as follows.
An example of an ultrasonic actuator using an ultrasonic vibration region as the vibration actuator will be described. FIG. 1 is a side view showing an ultrasonic actuator 21 of the present embodiment, and FIG. 2 is a longitudinal sectional view of the ultrasonic actuator 21. The ultrasonic actuator 21 of the present embodiment includes a rod-shaped fixed shaft 22, a vibrator 23 fixed and held on the fixed shaft 22, and a movable member 24 which is a relative motion member rotatably held on the fixed shaft 22. And Hereinafter, these components will be described.

The fixed shaft 22 is a rod-shaped member, and has a threaded portion on the upper end 22a side. On the other hand, the lower end 22b side is fixed and installed on a fixing portion of a mounting target device (not shown). Further, the fixed shaft 22 has bolt through holes 25a,
25b, 25c and 25d are formed, and a fixing pin through-hole 26 is formed substantially at the center in the longitudinal direction.

The vibrator 23 has semi-hollow cylindrical elastic bodies 27a and 27b obtained by vertically dividing a hollow cylindrical elastic body into two planes including a central axis, and semi-hollow cylindrical elastic bodies 27a and 27b. An electromechanical transducer 28a, which is a piezoelectric element for torsional vibration, and an electromechanical transducer 28b, which is a piezoelectric element for longitudinal vibration, are arranged in a state where two layers are stacked on each of the two divided surfaces. Is done.

The semi-hollow cylindrical elastic members 27a and 27b are made of a metal material such as stainless steel or a plastic material. In this embodiment, it is made of stainless steel having a high density and a high elastic modulus. Therefore, the collision force or impact stress generated by the collision between the moving element 24 and the vibrator 23 can be increased. Thereby, the torque generated by the ultrasonic actuator can be increased. Grooves are provided on the side surfaces of the semi-hollow cylindrical elastic bodies 27a, 27b to form small diameter parts 30a, 30b, 30c. The small diameter portion is formed in the hollow cylindrical elastic body before the division into two.
The small diameter portions 30a and 30c are semi-hollow cylindrical elastic bodies 27a,
The small-diameter portion 30b is formed at a node position of the secondary torsional vibration generated in the semi-hollow cylindrical elastic body 27a, 27b.
It is formed at the node position of the primary longitudinal vibration generated at 27b.
The small-diameter portions 30a to 3
0c is formed by semi-hollow cylindrical elastic bodies 27a, 27a.
This is to make the resonance frequencies of torsional vibration and longitudinal vibration generated in b close to each other or coincide with each other.

The semi-hollow cylindrical elastic bodies 27a and 27b include:
By being separated by the small diameter portions 30a to 30c,
Large diameter portions 30A, 30B, 30C and 30D are formed. Bolt through holes 31a, 31b, 31c and 31d are formed substantially at the center of the large diameter portions 30A to 30D in the transducer longitudinal direction, and fixed at substantially the center of the small diameter portion 30b in the transducer longitudinal direction. Pin through hole 32
Is formed.

The hole diameters and installation pitches of the bolt through holes 31 a to 31 d are determined by the bolt through holes 25 formed in the fixed shaft 24.
Match the hole diameter and the installation pitch of a to 25d. Also,
The hole diameter and the installation position of the fixed pin through hole 32 are made to match the hole diameter and the installation position of the fixed pin through hole 26.

Each of the piezoelectric element 28a for torsional vibration and the piezoelectric element 28b for longitudinal vibration is an electromechanical transducer for converting electric energy into mechanical displacement. Each piezoelectric element is formed in a thin plate shape by PZT. The piezoelectric element 28a for torsional vibration includes semi-hollow cylindrical elastic bodies 27a, 27a.
The electrode 31e is disposed at a position including one of the two node positions of the torsional vibration generated in b with the electrode 31e interposed therebetween. On the other hand, the piezoelectric element 28b for longitudinal vibration is disposed at a position including a node position of longitudinal vibration generated in the semi-hollow cylindrical elastic bodies 27a, 27b with the electrode 31f interposed therebetween.

The vibrator 23 has a semi-hollow cylindrical elastic body 27
a, 27b, two layers of piezoelectric elements 28a, 28b
A hollow portion is formed by bonding and fixing the electrode 8b and the electrodes 31e and 31f. The fixed shaft 22 to which the annular collar members 22c and 22d are attached is inserted into this hollow portion. Bolts 33 a,
33b, 33c and 33d are respectively inserted into the bolt through holes 25.
Then, the nuts 34a, 34b, 34c, and 34d are screwed after penetrating the bolts a to 25d and the bolt through holes 31a to 31d. Further, the fixed pin through hole 26 and the fixed pin through hole 3
2 is fixed by the fixed shaft 22 in a state shown in FIG. The collar members 22c and 22d are provided to prevent shaft runout when the fixed shaft 22 is driven.

The movable element 24 has a hollow, substantially cylindrical movable element base material 36 having a small diameter portion 36a at an end remote from the oscillator 23, and an end face of the movable element base material 36 on the oscillator 23 side. An annular sliding member 37 to be attached and a gear 38 which is a motion transmitting member to be fitted into the small diameter portion 36a are provided.

In the present embodiment, the moving element base material 36 is made of stainless steel.
6b is formed, and a sliding member 37 is attached to an end face of the convex portion 36b. A groove 39 is formed in an annular shape on the end face side of the mover base material 36 away from the vibrator 23, and a bearing 40 is fitted into the groove 39. The bearing 40 is supported on the fixed shaft 22. This allows
The moving element base material 36 is rotatably supported by the fixed shaft 22.

The annular gear 38 is fitted into the small diameter portion 36 a of the moving element base material 36. That is, the gear 38 does not need to have a high density, but only needs to have a strength necessary for transmitting the driving force. Further, since the gear 38 is provided on the outer peripheral portion of the moving element base material 36, the mass of the gear 38 has a large influence on the inertia moment generated in the moving element base material 36. Gear 38
Is large, the moment of inertia increases, and the rotational response speed of the moving element 24 decreases. For this reason, in the present embodiment, the material of the moving element 24 is an aluminum alloy having a high specific strength, and the surface is anodized to further improve abrasion resistance.

In the present embodiment, the moving element base material 36 and the gear 38 are fitted, but other methods may be used. For example, by using means such as press-fitting, bonding, or keyway file, a gear 38
May be fixed. Further, these methods may be appropriately combined and fixed. In the present embodiment, a gap 41 between the moving element base material 36 and the gear 38 with respect to the vibration direction (vertical direction in the drawing) of the longitudinal vibration generated in the semi-hollow cylindrical elastic bodies 27a and 27b is provided.
It is formed in an annular shape.

On the upper part of the bearing 40, a pressing force transmitting member 42 formed with an outward flange is held by a fixed shaft 22. In addition, the screw portion 22 formed on the fixed shaft 22
A nut 43 as a pressing force adjusting member is screwed and fixed to a. A disc spring 44 as a pressing member is mounted between the pressing force transmitting member 42 and the nut 43. By adjusting the screwing position of the nut 43 with respect to the fixed shaft 22, the spring force of the disc spring 44 is adjusted, and the pressing force between the vibrator 23 and the moving element 24 is adjusted. Note that a coil spring, a leaf spring, or the like may be used as the pressing member in addition to the disc spring 44.

In the vibration actuator 21 of the present embodiment configured as described above, the piezoelectric element 28 for torsional vibration
a, from a drive voltage generator (not shown) for each of the piezoelectric elements 28b for longitudinal vibration, via electrodes 31e and 31f.
When a two-phase driving voltage having a phase difference of (π / 2) is applied, the semi-hollow cylindrical elastic bodies 27a and 27b are affected by the primary longitudinal vibration in the axial direction of the vibrator and the axial direction of the vibrator. 2
The following torsional vibration occurs. The generated longitudinal vibration and torsional vibration are combined, and an elliptical amplitude is generated on the driving surface 23a, which is one end surface of the vibrator 23.

The generated elliptical amplitude is transmitted to the moving element 24 which comes into pressure contact with the driving surface 23a. Thereby, the moving element 24 is driven to rotate. At this time, the longitudinal vibration generated in the vibrator 23 has a clutch effect of intermittent contact between the vibrator 23 and the moving element 24, and propagates the torsional vibration generated in the vibrator 23 in only one direction. Therefore, in order to maintain the performance of the vibration actuator 21 of this embodiment as high as possible, the vibrator 23 and the moving element 24 are brought into contact by the It is important that

Here, when the vibrator 23 and the moving element 24 collide with each other due to longitudinal vibration, impact stress due to the collision is generated on the contact surface of the moving element 24. The generated impact stress sequentially propagates inside the moving element 24. In order to effectively use the vibration energy of the longitudinal vibration, it is necessary to minimize the energy due to the collision to the outside of the moving element 24 as much as possible. Is crucial.

In this embodiment, a gap 41 is provided between the moving element base material 36 and the gear 38 so that the impact stress generated in the moving element 24 is not propagated to the gear 38 as much as possible. , The moving element base material 36 and the gear 38 are separated. As a result, the end surface of the movable element base material 36 opposite to the sliding surface is a free end due to the formation of the gap 41. Therefore, when the impact stress generated in the movable element 24 at the contact surface between the movable element 24 and the vibrator 23 is reflected on the end face opposite to the sliding surface of the movable element base material 36, Will not spread to As a result, it is possible to reliably reflect the impact stress generated in the movable element 24 on the end face of the movable element base material 36 opposite to the sliding surface.

The reflected impact stress reaches the contact surface of the moving element 24 with the vibrator 23. As described above, the energy of the longitudinal vibration propagates into the moving element 24. As a result, the vibration energy of the longitudinal vibration is effectively used, and the vibrator 23 and the moving element 24 are easily separated. Thereby, when the gap portion 41 is not formed, the moving element 24
The improper separation between the vibrator 23 and the moving element 24, which is caused by the impact stress generated in the vibration element 23 being diffused to the outside of the moving element 24 through the gear 38, is eliminated. Therefore, reduction of the rotation speed and torque of the vibration actuator 21 and instability of driving in the low-speed rotation range are eliminated.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. In the following description of each embodiment, only portions different from the above-described embodiment will be described, and redundant description of common portions will be omitted as appropriate. In the present embodiment, the gear 38 is made of a resin material such as polyacetal, nylon, or a resin containing PTFE. By using these resin materials, it is possible to improve quietness and abrasion resistance, prevent damage to gears meshing with the gears 38, reduce weight, and reduce costs by injection molding. Further, since these resin materials have solid lubricating properties, there is basically no need to use a lubricating oil. Therefore, the possibility that the lubricating oil leaks to the contact surface between the vibrator 23 and the moving element 24 to cause power transmission failure is eliminated.

Further, to these resin materials, glass fibers, carbon fibers, whiskers and the like may be added to the above-mentioned resin materials in order to improve the strength. In addition, it is desirable to use press fitting for fixing to the moving element base material 36. In the case where the gear 38 is formed of a resin material having a large vibration absorbing ability, if the gap portion 41 is not formed, the shock stress generated in the moving element 24 is absorbed by the gear 38 and the vibrator 23 and the moving element It is extremely easy to cause separation failure between the two. Therefore, when the gear 38 is made of a resin material, the moving child base material 36 and the gear 38
Providing the gap portion 41 between them has a particularly large effect.

(Third Embodiment) FIG. 3 is a sectional view showing a moving element 24-1 of an ultrasonic actuator 21-1 according to a third embodiment. The moving element 24-1 of the ultrasonic actuator 21-1 according to the present embodiment is different from the moving element 24 of the ultrasonic actuator 21 according to the first embodiment not only in the bearing 40 but also in the pressing force transmitting member 42 and the nut. 43 and a disc spring 44 are also incorporated in the moving element base material 36. With this configuration, it is possible to reduce the overall length of the ultrasonic actuator 21-1.

(Fourth Embodiment) FIG. 4 is a sectional view showing a moving element 24-2 of an ultrasonic actuator 21-2 according to a fourth embodiment. The ultrasonic actuator 21-2 according to the present embodiment is a further improvement of the ultrasonic actuator 21-1 according to the third embodiment, and an annular groove 45 is formed in the gear 38 to form an elastic deformation portion 46. . That is, in the ultrasonic actuator 21-2 of the present embodiment, the gear 38 receives a reaction force in the radial direction from a mating gear (not shown) that meshes with the gear 38 when driven.
Due to this reaction force, the contact surface of the moving element 24-2 with the vibrator 23 may be inclined, and the adhesion to the vibrator 23 may be reduced, and the driving performance may be reduced. Further, the vibration of the gear 38 generated when the gear 38 is rotated is
6, the adhesion to the vibrator 23 is reduced, and the driving performance may be similarly reduced.

Such an ultrasonic actuator 21-2
In order to prevent the performance degradation, the elastic deformation portion 46 is formed by forming the groove portion 45 in the gear 38, and the external force that inclines the movable member 24-2 is absorbed by the elastic deformation of the elastic deformation portion 46. Thereby, even if the gear 38 receives a reaction force or generates vibration from the gear of the mating gear, the elastic deformation portion 46 is elastically deformed, so that the close contact between the moving member 24-2 and the vibrator 23 is maintained. It is. As a result, it is possible to prevent a reduction in driving performance due to a radial reaction force received by the gear 38. In this embodiment, the gear 38 has an elastically deformable portion 46.
Is formed. As described above, the elastic deformation portion 46 may be formed integrally with the gear 38 as the motion transmitting member, or may be formed on the moving member 24-2. Further, the gear 38,
The moving member 24-2 may be formed on another member.

(Fifth Embodiment) FIG. 5A shows a moving element 24-3 of an ultrasonic actuator 21-3 according to a fifth embodiment.
FIG. 5B is a top view showing a cam 47 which is a driving force extracting member attached to the moving member 24, and FIG. 5B is a cross-sectional view showing a moving member 24-3 of an ultrasonic actuator 21-3 of the fifth embodiment. is there. In the ultrasonic actuator 21-3 according to the present embodiment, the cam 47 is provided to the movable element 24-3 as a driving force extracting member.
And fit it. As described above, by changing the driving force extracting member, it is possible to obtain the driving force in a desired form. In addition to the gear 38 in the first to fourth embodiments and the cam 47 in the fifth embodiment, for example, a crank or the like can be installed.

(Sixth Embodiment) FIG. 6 is a longitudinal sectional view showing an ultrasonic actuator 21-4 according to a sixth embodiment. In the ultrasonic actuator 21-4 of the present embodiment, the fixed pin 35 is installed at a node position closer to the moving element 24 among the two node positions of torsional vibration generated in the oscillator 23. This node position is a position where the small diameter portion 30a is formed. Thereby, since the torsional vibration generated in the vibrator 23 is hardly restricted, it is possible to ensure a large amplitude of the torsional vibration generated in the vibrator 23. As a result, the number of revolutions of the ultrasonic actuator 21-4 can be increased, and the high-rotation type ultrasonic actuator 21-
4 can be provided. Further, the vibration actuator 21-4 of the present embodiment includes a coil spring 4 as a pressing member.
7 is used. The upper end of the coil spring 47 is supported by a pressure ring 48. The position of the coil spring 47 in the axial direction is fixed by a retaining ring 49.
In addition, this pressurizing member is the same as the other embodiments,
4 or a leaf spring or the like may be used.

The ultrasonic actuator 21 of the present embodiment
The fourth moving element 24-4 is the moving element 24-2 according to the fourth embodiment.
Is further improved. By forming annular grooves 45 on both end surfaces of the gear 38, an elastically deformable portion 46 is formed at a substantially central position in the thickness direction of the gear 38.
As shown in FIG. 6, the elastic deformation portion 46 is arranged such that the position in the axial direction is inside the region 50 a where the gear 38 and the gear 50, which is the driven member driven by the gear 38, come into contact. Have been. Since the elastic deformation portion 46 is arranged inside the contact area 50a between the gear 38 and the gear 50 in the axial direction, the axial deflection of the gear 38 caused by the deformation of the elastic deformation portion 46 can be reduced. Therefore, a change in the distance between the shafts of the gear 38 and the gear 50 can be reduced. As a result, an appropriate distance between the shafts is maintained, and gear driving with less reaction can be performed. Further, the elastic deformation portion 46 is provided with the bearing 40 in the axial direction.
It is good to arrange so that it may be located in the same position as. Thus, the radial reaction force of the gear 38 received from the gear 50 acts at the same position as the bearing 40 in the axial direction. As a result, the moment that deteriorates the adhesion between the vibrator 23 and the moving element 24 can be reduced.

(Seventh Embodiment) FIG. 7 is a sectional view showing a movable element 24-5 of an ultrasonic actuator 21-5 according to a seventh embodiment. The mover 24-5 of the present embodiment
In this embodiment, the moving element base material 36 and the gear 38 of the moving element 24-1 according to the third embodiment are integrally formed. This allows
In addition to having the same effects as the third embodiment, the moving child base material 3
Since the gear 6 and the gear 38 are integrally formed, the accuracy of the inclination of the movable element with respect to the axial center is improved. Further, the dimensional accuracy when processing the moving element is improved. As a result, it is possible to provide a vibration actuator with less rattling of the moving element.

(Eighth Embodiment) FIG. 8 is a cross-sectional view showing a moving element 24-6 of an ultrasonic actuator 21-6 according to an eighth embodiment. The mover 24-6 of the present embodiment
In this embodiment, the moving element base material 36 and the gear 38 of the moving element 24-2 according to the fourth embodiment are integrally formed. This allows
In addition to having the same effects as the fourth embodiment, the moving child base material 3
Since the gear 6 and the gear 38 are integrally formed, the accuracy of the inclination of the movable element with respect to the axial center is improved. Further, the dimensional accuracy when processing the moving element is improved. For this reason, it is possible to provide a vibration actuator with less rattling of the moving element.

(Ninth Embodiment) FIG. 9 is a longitudinal sectional view showing an ultrasonic actuator 21-7 according to a ninth embodiment. The vibration actuator 21-7 of the present embodiment is
Moving element base material 3 of vibration actuator 21-4 of embodiment
6 and the gear 38 are integrally formed. Thus, in addition to having the same effect as in the sixth embodiment, since the mover base material 36 and the gear 38 are formed integrally, the accuracy of the inclination of the mover with respect to the axial center is improved. Further, the dimensional accuracy when processing the moving element is improved. For this reason, it is possible to provide a vibration actuator with less rattling of the moving element.

(Modification) In each of the embodiments described in detail above, the ultrasonic actuator is used as the vibration actuator. However, the vibration actuator according to the present invention is not limited to such an embodiment, and other vibration actuators may be used. The same applies to a vibration actuator using a region. In each embodiment, a piezoelectric element is used as the electromechanical conversion element. However, the vibration actuator according to the present invention is not limited to such an aspect, and can convert electric energy into mechanical displacement. If they apply equally. In addition to the piezoelectric element, for example, an electrostrictive element can be exemplified.

Further, in each of the embodiments, the case where the primary longitudinal vibration and the secondary torsional vibration are generated in the vibrator is taken as an example, but the vibration actuator according to the present invention has such a mode. The present invention is not limited thereto, and the present invention is equally applied to a vibration actuator that generates a primary or higher-order longitudinal vibration and a secondary or higher-order torsional vibration.

In each embodiment, a vibration actuator of a type in which a torsional vibration piezoelectric element and a longitudinal vibration piezoelectric element are sandwiched between divided surfaces of two semi-hollow cylindrical elastic bodies is described as an example. The vibration actuator according to the present invention is not limited to such a type, but includes a columnar vibrator that generates longitudinal vibration and torsional vibration, and a columnar relative motion member that comes into pressure contact with one end face of the vibrator. And the motion transmitting member provided on the relative motion member.

[Brief description of the drawings]

FIG. 1 is a side view showing an ultrasonic actuator according to a first embodiment.

FIG. 2 is a longitudinal sectional view of the ultrasonic actuator according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a moving element of an ultrasonic actuator according to a third embodiment.

FIG. 4 is a cross-sectional view illustrating a moving element of an ultrasonic actuator according to a fourth embodiment.

FIG. 5A is a top view showing a cam which is a driving force extracting member mounted on a moving element of an ultrasonic actuator according to a fifth embodiment, and FIG. 5B is a top view showing the fifth embodiment; FIG. 5 is a cross-sectional view showing extracted moving elements of the ultrasonic actuator of FIG.

FIG. 6 is a longitudinal sectional view of an ultrasonic actuator according to a sixth embodiment.

FIG. 7 is a cross-sectional view illustrating a moving element of an ultrasonic actuator according to a seventh embodiment.

FIG. 8 is a cross-sectional view illustrating a moving element of an ultrasonic actuator according to an eighth embodiment.

FIG. 9 is a longitudinal sectional view of an ultrasonic actuator according to a ninth embodiment.

FIG. 10 is an explanatory view showing the structure of a vibration actuator proposed by Japanese Utility Model Laid-Open No. 4-2987.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Ultrasonic actuator 22 Fixed axis 23 Vibrator 24 Moving element (relative motion member) 25a-25d Bolt through hole 26 Fixed pin through hole 27a, 27b Semi-hollow cylindrical elastic body 28a Piezoelectric element for torsional vibration (electromechanical conversion) Element) 28b Piezoelectric element for vertical vibration (electromechanical conversion element) 30a to 30c Small diameter portion 30A to 30D Large diameter portion 31a to 31d Bolt through hole 31e, 31f Electrode 32 Fixed pin through hole 33a to 33d Bolt 34a to 34d Nut 35 Fixed Pin 36 Mover base material 36a Small diameter portion 36b Convex portion 37 Sliding member 38 Gear 39 Groove 40 Bearing 41 Gap 42 Pressure transmitting member 43 Nut 44 Disc spring 45 Groove 46 Elastic deformation portion 47 Coil spring 48 Press ring 49 Stop ring 50 gears

Claims (9)

[Claims] 1. A columnar vibrator that generates longitudinal vibration in the axial direction and torsional vibration in the axial direction, a relative motion member that presses and contacts one end surface of the vibrator, and a relative motion member. A vibration actuator, comprising: a motion transmitting member provided; and a vibration preventing mechanism for preventing propagation of the longitudinal vibration to the motion transmitting member. 2. The vibration actuator according to claim 1, wherein the vibration preventing mechanism is disposed between the relative motion member and the motion transmitting member, and is provided along a direction intersecting a vibration direction of the longitudinal vibration. A vibration actuator characterized by having a clearance. 3. The vibration actuator according to claim 1, wherein the vibration preventing mechanism is disposed between the relative motion member and the motion transmission member, and has an elastic deformation portion. Vibration actuator. 4. The vibration actuator according to claim 3, wherein the position of the elastic deformation portion in the axial direction is such that the motion transmitting member and a driven member driven by the motion transmitting member are in contact with each other. A vibration actuator, which is arranged so as to be inside a region. 5. The vibration actuator according to claim 3, wherein the elastic deformation portion is coupled to the relative motion member at an end face of the motion transmission member on the vibrator side. 6. The vibration actuator according to claim 3, wherein the elastic deformation portion is provided at a position substantially at the center in the axial direction of the motion transmitting member. 7. The vibration actuator according to claim 3, wherein a fixed shaft supporting the vibrator and the relative motion member is provided on the relative motion member to support the relative motion member with respect to the fixed shaft. A vibration member, further comprising: a support member configured to move the elastically deformable portion and the support member at substantially the same position in the axial direction. 8. The vibration actuator according to claim 1, wherein the motion transmitting member is made of a resin material. 9. The vibration actuator according to claim 1, wherein the motion transmitting member is a gear or a cam.