JPS6237075A - vibration wave motor - Google Patents

Abstract

PURPOSE:To improve the workability of an elastic body without deteriorating the performance of a motor by dividing the elastic both with a projection into two sections. CONSTITUTION:An oscillating body 8 for an oscillatory wave motor is constituted of a piezoelectric body 1, an elastic body 6 and a projection group 7. The elastic body 6 and the projection group 7 correspond to a conventional elastic body, and are each divided, and the elastic body 6 is formed by duralumin, etc. having the little internal loss of oscillations, and the projection group 7 is shaped by a molded shape consisting of aluminum, etc. Projecting sections 7a and a connecting section 7b are formed integrally in the projection group 7. A stepped section 6b is shaped to the peripheral section of the elastic body 6, and the projection group 7 is positioned and joined. Accordingly, the elastic body can be divided into two sections and formed, thus minimizing the internal loss of elastic body itself while shortening the working time of the projection and reducing the working cost thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a vibration wave motor using progressive vibration waves.

[Prior art]

Vibratory wave motors use the vibrational motion that occurs when a frequency voltage is applied to a piezoelectric vibrator, for example, for driving. Compared to conventional electromagnetic motors, they do not require windings, so they have a simpler and more compact structure. It has the advantage of being able to obtain high torque even when rotating at low speeds, and has attracted attention in recent years.

As a means for exciting vibrations in the vibrating body, an electro-mechanical transducer that periodically deforms, such as a piezoelectric element, an electrostrictive element, or a magnetostrictive element, may be used. However, for the sake of simplicity, a piezoelectric element will be used as an example hereafter. explain.

The vibration wave motor frictionally drives a movable body by the vibration of the vibrating body, and therefore, the vibrating body is usually resonated in a desired vibration mode so as to generate large vibrations in the vibrating body. As a means of transmitting the displacement of the vibrating body to the movable body, there is a method of using a protrusion as a pusher, for example, as disclosed in JP-A-58-192474, and a structure for magnifying the displacement is disclosed in JP-A-58-192474. It is disclosed in No. 59-178988 and Japanese Patent Application Laid-open No. 59-201685.

Figure 1 is a diagram explaining the configuration of the conventional device for increasing displacement, and Figure 2 is a diagram explaining its operating principle. In Figure 0, l is a piezoelectric body, 2 is an elastic body, and 3 is a moving body. body, 4
5 is a supporting vibration absorbing material, and 5 is a fixed body. For example, as shown in the plan view of FIG. 3, the piezoelectric body 1 has a fan-shaped portion indicated by a dotted line that is polarized in the thickness direction indicated by (+) and (-) symbols, and has A-phase and B-phase piezoelectric elements. It is divided into element groups.

Since the configuration for generating progressive surface waves in the piezoelectric body is well known, a detailed explanation thereof will be omitted, but an AC voltage V = Vo sin w is applied to the A-phase piezoelectric element group represented by 1a.
t is applied (not shown), and to the B-phase piezoelectric element group represented by 1b located at a position with a phase shift of 1/4, ■=±VOc.
The elastic body 2 is joined to the piezoelectric body l by applying os wt.
It generates a progressive bending surface wave, and the direction of travel can be changed by the samurai.

In addition, the protrusion r disposed on the elastic body 2 has a displacement expanding configuration for enlarging the amplitude of the progressive bending surface wave, and the amplitude expansion rate is determined by the length of the protrusion r. If it is designed to resonate with the next bending vibration, the amplitude will be further expanded.

The movable body 3 presses into contact with the elastic body 2 with a pressurizing force W, and the bending surface waves generated in the elastic body 2 as described above push the movable body 3 due to frictional force.
It moves at a speed of V. The vibrating body composed of the piezoelectric body 1 and the elastic body 2 is supported by a vibration absorbing material 4 such as felt, and has a structure in which vibrations are not transmitted to the fixed body 5 as shown in the second figure.

In the vibration wave motor having the above configuration, the elastic body 2 is made of duralumin, brass, etc., which has low internal loss, and the conventional method for forming the protrusions τ is to form each protrusion from the elastic body 2 by milling or wire-cut electric discharge machining. It had to be cut out, which caused problems in terms of processing time and processing cost.

〔the purpose〕

An object of the present invention is to improve the workability of the elastic body, which was a drawback of the above-mentioned conventional example, without degrading the performance of the motor.

In the present invention, the elastic body is divided into two parts: an elastic body that contacts the piezoelectric body, and a displacement magnification mechanism such as a protrusion that is joined to the elastic body, and this displacement magnification mechanism can be integrally formed by molding,
The aim is to achieve the above objectives.

〔Example〕

4 and 5 are a perspective view and a sectional view, respectively, showing the structure of the vibrating body of an embodiment of the vibration wave motor according to the present invention, in which 1 is a piezoelectric body, 6 is an elastic body, and 7 is a protrusion. The vibrating body 8 is constituted by these groups. The piezoelectric body 1 has the conventional structure shown in FIG. 3, but the elastic body 2 in the conventional device is divided into an elastic body 6 and a group of projections 7. The elastic body 6 is an elastic body mainly made of metal, and duralumin, brass, or the like, which has low internal vibration loss, is used. Further, the protrusion group 7 is a molded product made of aluminum and zinc die-casting, resin material, etc., and the protrusion part 7a and the connecting part 7b are integrally formed. A stepped portion is provided at the periphery of the elastic body 6, and is positioned in the radial direction by the stepped portion 6b of the elastic body 6 and the connecting portion 7b of the protrusion group 7, and the protrusion 7a
The contact portion between the elastic body surface 6a and the elastic body surface 6a are joined with adhesive or the like to form an integral structure.

FIG. 6 is a cross-sectional view showing the structure of the vibrating body when it is incorporated into the class 8 camera lens shown in FIGS. 4 and 5. In FIG. 6, 8 is a vibrating body having the above structure, 9 is a rotor as a moving body that comes into contact with the protrusion 7a of the vibrating body 8, 10 is a rotating helicoid that rotates with the rotation of the rotor 9, and 11 is a linear lens barrel. , 12 are pressure disc springs that press the vibrating body 8 into contact with the rotor.

In this configuration, the vibrating body 8 is pressed into contact with the rotor 9 by the disc spring 12, and the rotating helicoid 10 is rotated by causing the vibrating body to form progressive vibration waves as described above. The rotating helicoid is threaded and the linear lens barrel 11 is prevented from rotating, so the rotation of the helicoid 10 causes the linear lens barrel 1 to move.
1 moves linearly in the optical axis direction and performs focusing of the lens.

FIGS. 7(L) to (e) are sectional views showing other embodiments of the vibrating body in the vibration wave motor according to the present invention.

In each figure, l represents a piezoelectric body, 6 represents an elastic body, and 7 represents a group of protrusions. Further, in the elastic body 6, 6a represents a joint surface that is joined to the bottom surface of the projection group 7, and 6b represents a step portion that positions the connecting portion 7b of the projection portion in the radial direction. On the other hand, in the projection group 7, 7a represents a projection, and 7b represents a connecting portion that integrally connects the projections.
It is made in one piece using the same molding process as shown in the figure.

FIG. 7(a) shows an example in which the connecting portion 7b shown in FIG. 4 is arranged inside the ring, and the stepped portion 6b is similarly arranged inside the ring.

In Fig. 7(b), the connecting part 7b and the stepped part 6b are arranged in the center of the elastic body, and the width of the protruding part 7b is made narrower than the width of the elastic body to reduce the weight. .

In FIG. 7(C), the width of the upper part of the projection 7a in the embodiment of FIG. 4 is narrowed to reduce the weight.

In FIG. 7(d), similarly to FIG. 7(c), the width of the upper part of the projection 7a is narrowed, and a stepped portion 7c is further provided, and the rotor 13 shown by the two-dot chain line is held down by the stepped portion 7C. It is designed to prevent axis misalignment during rotation.

In FIG. 7(e), the elastic body in FIG. 4 is changed from a rectangular cross section to an irregular cross section (wider in the joining direction with the piezoelectric body and narrower in the direction of the protrusion 7a), and the neutral axis position is lowered to further increase the amplitude. This is an enlarged version.

In FIG. 7(e), the connecting portion 7b is positioned on the side surface of the elastic body.

〔effect〕

As explained above, in the present invention, by dividing the elastic body having projections into two parts, the elastic body itself that performs resonance is used as a conventional material with low internal loss, and the projections and molding are It is designed so that it can be formed integrally. Therefore, the processing time and processing cost for making the protrusions can be significantly reduced compared to the conventional method.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the configuration of a conventional vibration wave motor;
The figure is an explanatory diagram of the operation of the motor shown in the first figure. FIG. 3 is a plan view of the piezoelectric body shown in FIG. 1, and FIG. 4 is a plan view of the piezoelectric body shown in FIG. FIG. 5 is a perspective view and a cross-sectional view showing an example of a vibrating body in a vibration wave motor according to the present invention, FIG. 6 is a configuration diagram when the vibration wave motor of the present invention is incorporated into a camera lens, and FIG. (a) to (e) are sectional views showing other embodiments of the vibrating body according to the present invention. 1 is a piezoelectric body, 2 and 6 are elastic bodies, 7 is a group of protrusions, 8 is a vibrating body, and 3 is a moving body. Section <0> (e) Figure 7 (b)

Claims (1)

[Scope of Claims] A signal wave motor that generates a progressive surface wave in the elastic body by bonding a periodically deforming electro-mechanical conversion element to the elastic body, and drives a moving body with the surface wave, A vibration wave motor, characterized in that a progressive vibration wave expansion mechanism formed by molding is disposed between the elastic body and the movable body.