JPS60210173A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To enhance the output and the efficiency of a vibration wave motor by using the peripheral surface of vibrator as a contacting surface of a moving elements in a motor for generating a traveling vibration wave at a ring-shaped vibrator with an electrostrictive element to drive the element, thereby utilizing the vibration of the direction perpendicular to the ring surface. CONSTITUTION:A polarized ring-shaped electrostrictive element 12 of a plurality of electrostrictive elements are bonded to the planar surface of a ring-shaped vibrator 31, a frequency voltage is applied to the element 12 to allow the vibrator 31 to generate a traveling vibration wave. A movable elememt 35 energized by a spring 20 is frictionally contacted with the peripheral surface of the inner or outer peripheral surface side of the vibrator 31, and rotatably driven by the traveling vibration wave. Thus, the element 35 is activated to be vibrated perpendicularly to the planar surface as compared with the case that the element 35 is contacted with the planner surface of the vibrator 31. Accordingly, a motor having a high output in a high efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a rotary vibration wave motor driven by progressive vibration waves.

A vibration wave motor converts the vibration motion generated when a frequency voltage is applied to an electrostrictive element into rotational motion or -dimensional motion, and has a simpler structure than conventional electromagnetic motors because it does not require windings. It has been attracting attention in recent years because it has the advantage of being small in size and being able to obtain high torque even when rotating at low speeds.

1 and 2 show the driving principle of a conventional vibration wave motor, and FIG. 1 shows the state in which vibration waves are generated by the motor. The electrostrictive elements 2a and 2b bonded to the vibrating body 1 (usually metal) are arranged on one side of the vibrating body 1 at a moderate distance from each other so as to spatially satisfy a phase shift of /4. There is.

The vibrating body l is used as one electrode of the electrostrictive elements 2a and 2b, and the electrostrictive element 2a is supplied with V=Vosin (J
)t, input to the electrostrictive element 2b through a 90″ phase shifter 3b/
The (+) and (-) in the above formula for applying an AC voltage of V=Vosin (ωt±π/2) with four phases shifted are switched by the phase shifter 3b depending on the direction in which the moving body 5 is moved.

It is now switched to the (-) side, and the electrostrictive element 2b has V=V.
Assume that a voltage of o sin (ωt-π/2) is applied. Only the electrostrictive element 2a has a voltage V=Vos
When the electrostrictive element 2b vibrates due to the voltage V=Vosin(ωt-π/2), vibration occurs due to a standing wave as shown in FIG. Vibration occurs due to standing waves as shown in FIG. 2(b). When the two phase-shifted AC voltages are simultaneously applied to each electrostrictive element 2a, 22b, the vibration wave becomes progressive.

(A) is time t = 2nπ/ω, (B) is t = π/2ω + 2nπ/ω, (C) is t =
π/ω+2nπ/ω, (d) is when t=3π/2ω+2nπ/ω,
The wavefront of the vibration wave travels in the X direction.

Such progressive vibration waves are accompanied by longitudinal waves and transverse waves, and if we focus on the mass point A of the vibrating body l as shown in Fig. 2, we can see that it forms an ellipse of revolution in the counterclockwise direction with a longitudinal amplitude U and a transverse amplitude W. Exercising. Since the movable body 5 is in pressure contact with the surface of the vibrating body 1 and is in contact only with the apex of the vibrating surface (actually, it is in surface contact with a certain width), the mass points A and A at the apex are ', ---- Driven by the component of the longitudinal amplitude U of the one elliptical motion, the moving body 5 moves in the direction of the arrow N. 90
``If the phase is shifted by +90° using a phase shifter, the vibration wave will proceed in the -X direction, and the moving body 5 will move in the opposite direction to the N direction.

FIG. 3 shows the structure of a rotary vibration wave motor that uses this vibration wave motor to generate rotational motion. FIG. 4 is a sectional view thereof. In FIG. 3, 11 is an elastic vibrating body mainly made of metal, 12 is an electrostrictive element joined to the vibrating body 11, 15 is a moving body that presses into contact with the vibrating body 11,
16 is a rotating disk (rotating shaft), 17 is a vibration absorber that supports the vibrating body 11, and 18 is a fixed body.

A frequency voltage is applied from an external power source to an electrostrictive element 12 having a structure similar to that of the electrostrictive element 2, and a driving frequency is set such that the vibrating body 11 resonates. Frictional force acts on the movable body 15 that is pressed into contact with the vibrating body 11 via the thrust bearing 9 by the spring 20, and the rotating shaft 16 joined to the movable body 15 rotates. The fixed cover 21 is fixed to the fixed body 18 with screws 22, and has a structure in which the ultrasonic vibration of the vibrating body 11 is not transmitted to the fixed body 18 by inserting a vibration absorber 17 between the electrostrictive element 12 and the fixed body 18. It becomes.

However, when this vibration wave motor is rotated, since the vibrating body 11 has a ring shape, it not only vibrates in the mode shown in Fig. 2, but also vibrates in a direction perpendicular to the ring surface. Bending vibration occurs in the direction, and twisting occurs around the circumferential direction of the ring surface as shown in Figure 5, and both bending vibration perpendicular to the ring surface and twisting around the circumferential direction of the ring surface occur. . Here, in the vibration wave motor, since the moving body 15 is driven using a traveling wave caused by a bending vibration generated in a direction perpendicular to the ring surface, a traveling wave caused by a torsional component of vibration generated around the circumferential direction of the ring surface is used. Because this was not used effectively, the energy of the torsional component of vibration generated around the circumference was lost.

Therefore, there is a drawback that the efficiency of the vibration wave motor is reduced.

Furthermore, since the amplitude of the torsional component of the vibration around the circumferential direction of the ring surface of the vibrating body 11 increases from the inner diameter side to the outer diameter side of the ring surface as shown in FIG. The elliptical motion of the mass point that occurs in the curve increases from the inner diameter side to the outer diameter side. As a result, the movable body 15 mainly contacts the outer diameter side portion of the ring surface, and does not contact the inner diameter side portion of the ring surface of the vibrating body 11.

That is, the contact area between the movable body 15 and the vibrating body 11 becomes substantially small, and the efficiency with which the traveling wave of the vibrating body 1 is transmitted to the movable body 15 decreases, resulting in a disadvantage that a sufficient output cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a novel vibration wave motor with a large contact area, high efficiency, and high output.

Here, the present invention uses the inner diameter or outer diameter surface of the vibrating body of the vibration wave motor as the contact surface with the moving body, and the bending vibration component perpendicular to the ring surface of the vibration of the vibrating body, as in the conventional vibration wave motor. It does not primarily utilize the torsional component of the vibration of the vibrating body around the circumferential direction of the ring surface, or the bending vibration component within the ring surface of the vibrating body. It is characterized by its use.

The present invention will be explained in detail below using the drawings.

FIG. 6 is a sectional view 9 showing an embodiment of the present invention, in which 31 is a vibrating body, 35 is a moving body, 36 is a rotating disk (rotating shaft), and the other parts have the same structure as in FIG. 4. Elements with the same functions are given the same reference numerals and their explanations are omitted.

FIG. 7 is an explanatory diagram of the driving principle, and FIG. 8 is a diagram illustrating the driving principle of the moving body 45a.
, 45b, vibrating bodies 41a, 41b, and an electrostrictive element 12. FIG. Figure 8(a)
An embodiment in which the inner diameter surface of the vibrating body is the contact surface with the moving body. The eighth drawing (b) shows the contact of the outer diameter surface of the vibrating body with the moving body. This is an example. As shown in Fig. 7(a), the driving frequency f is changed by bending in the direction perpendicular to the ring surface.As shown in Fig. 7(b), the driving frequency is changed to the resonance frequency f2 at which bending vibration occurs within the ring surface. Then, the vibrating body 11 and the electrostrictive element 12 move as shown by the dotted line.

FIG. 7(C) is a plan view showing the bending vibration within the ring plane of the vibrating body 11 and the electrostrictive element 12, and is a diagram in which the natural vibration mode of the vibrating body 11 is analyzed by the finite element method. (In the case of wave number force') In Fig. 7(C), 11' is a vibrating body, and the minute units to be analyzed by the finite element method are divided into lattices. Xl”
In order to clearly express the in-plane bending vibration of the in-plane bending vibrating body 11, the amplitude of the in-plane bending vibration of the vibrating body 11' is exaggerated. Incidentally, the aforementioned fl and f2 are generally determined by the following formula.

Here, A: Cross-sectional area of the vibrating body E: Young's modulus n: Wave number of vibration r: Radius of the vibrating body ring Ip: Polar moment of inertia of area υ: Poinn ratio Iy, Iz: X axis, moment of inertia of area about the X axis I/P: Density. Here, if the inner diameter surface (Fig. 8 (a)) or the outer diameter surface (Fig. 8 (b)) of the vibrating body is the contact surface of the moving body, the torsional component around the ring circumferential direction during out-of-plane vibration of the ring Alternatively, bending vibration within the ring plane can be used for driving.

In reality, as shown in Figures 6 and 8, as explained above, the inner diameter or outer diameter surface of the vibrating body is used as the contact surface with the moving body, and bending perpendicular to the ring surface and circumferential direction of the ring are performed. By using fast-forming vibration or bending vibration within the ring plane for driving, the contact area can be expanded according to the thickness of the vibrating body, resulting in high output and improved efficiency. Furthermore, since the contact surface is inclined with respect to the ring surface, it has a self-aligning effect, and stable output with little rotational unevenness can be obtained. Further, if a flat plate-shaped electrostrictive element is used, a simple structure can be achieved.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of the driving principle of the vibration wave motor, and Figure 3 is
4 are respectively a perspective view and a sectional view of a conventional vibration wave motor, FIG. 5 is a sectional view showing the vibration of a vibrating body and a moving body of a conventional vibration wave motor, and FIG. 7(a), (b), and (C) are detailed explanatory views of the present invention. FIG. 8(a), (b) is a cross-sectional view showing an embodiment of the present invention.
b, vibrator 41a, 41b electrostrictive element \ FIG. 1.11.31.41a and 41b are vibrating bodies, 5.15.
35.45a and 45b are moving bodies, 2.12 is an electrostrictive element,
17 is a vibration absorber. Figure 7? (d) No. r7 (α) (b) (C) Procedural amendment (method) % formula % 1. Indication of the case 1982 Patent Application No. 65400 2. Name of the invention Vibration wave motor 3. Amendment Relationship with the patent applicant case Address: 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (+0
0) Canon Co., Ltd. Representative Ryu Kaku 4, Agent residence 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, date of amendment order June 26, 1980 (shipment date) 6. Specification subject to amendment 7. Contents of correction

Claims (1)

[Claims] (1) A plurality of electrostrictive elements are joined to the plane part of a ring-shaped vibrating body in a phase difference manner, or a plurality of electrostrictive elements polarized in a phase difference manner are joined to the plane part, and a frequency voltage is applied to the electrostrictive element. A progressive vibration wave is generated in the vibrating body by applying an electric current to the vibrating body, and the progressive vibration wave rubs and drives a movable body that is brought into pressurized contact with the vibrating body. A vibration wave motor having a contact surface with the moving body. (2. The motor according to claim 1, wherein the vibration wave motor has a driving frequency set to a resonance frequency that generates bending vibration within the ring surface of the ring-shaped vibrating body.