JPH06106026B2 - Vibration wave motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration wave motor that uses a vibration of a vibrating body as a driving force to relatively move the vibrating body and a contact body.

<Prior Art> FIG. 1 shows a schematic view of an embodiment of a vibration wave motor driven by a progressive vibration wave, which has recently been put into practical use. In the figure, reference numeral 1 is an electrostrictive element, for example PZT (lead zirconate titanate), and 2 is a vibrating body made of an elastic material, and the electrostrictive element 1 is bonded. The vibrating body 2 is held on the stator (not shown) side together with the electrostrictive element 1. A moving body 3 is in pressure contact with the vibrating body 2 and forms a rotor. A plurality of electrostrictive elements 1 are adhered, and a group of some of them is arranged, and the other group is arranged with a pitch shifted by 1/4 wavelength of the wavelength λ of the vibration wave. Each electrostrictive element in the group is a half-wave pitch, and is arranged so that the polarities of adjacent ones are opposite.

With a vibration wave motor with such a configuration,
Applying an AC voltage of V ₀ sin (.omega.T), to apply an AC voltage V ₀ cos (.omega.T) electrostrictive element of the other group. Therefore, each electrostrictive element oscillates when an alternating voltage having a polarity opposite to each other and having a phase difference of 90 ° is applied between the two groups.
When this vibration is transmitted, the vibrating body 2 causes bending vibration according to the arrangement pitch of the electrostrictive element 1. When the vibrating body 2 projects at the position of every other electrostrictive element, the position of every other electrostrictive element retracts. On the other hand, as described above, one group of electrostrictive elements is at a position shifted by 1/4 wavelength from the other group, and therefore bending vibration proceeds. While the AC voltage is being applied, vibrations are excited one after another to form a progressive bending vibration wave and propagate through the vibrating body 2.

The wave traveling state at this time is shown in FIGS. 2 (a), (b) and (c).
It is shown in (d). A progressive bending vibration wave is now indicated by X ₁
Let's go in the direction. When 0 is the center plane of the vibrating body in the stationary state, the state shown by the chain line is in the vibrating state, and the neutral plane 6 is counteracted by the stress due to bending. As for section ₇₁ perpendicular to the neutral plane 6, only the line of intersection 5 ₁ of these two surfaces stress is vertical vibration not applied. Cross section at the same time
7 ₁ has left and right pendulum vibrations centering on the intersection line 5 ₁ . Similarly, for the cross section 7 ₂ or 7 ₃ , pendulum vibrations on the left and right are centered around the intersection line 5 ₂ or 5 ₃ .

Section ₇₁ and the movable body 3 of the vibrator 2 in the state shown in the diagram (a)
The point P ₁ on the line of intersection with the surface on the side is the right dead center of the left-right vibration and is only moving upward. This pendulum vibration is the intersection line 5 ₁
・ When 5 ₂ or 5 ₃ is on the positive side of the wave (when it is on the upper side of the center plane 0, it is added to the stress in the left direction (the direction opposite to the traveling direction X _{1 of the} wave), and on the negative side of the wave (also on the lower side) ) rightward stressed. that at a figure (a), in a state in intersection lines 5 ₂ and section 7 ₂ of the former, the point P ₂ is applied is arrow direction of stress. intersection line 5 ₃ And the cross-section 7 ₃ is the latter, stress is applied in the direction of the arrow at point P _3. When the wave progresses and the intersection line 5 ₁ comes to the positive side of the wave as shown in (b), point P 3 ₁ moves to the left and at the same time moves upward.In (c), point P ₁ moves only to the left at the top dead center of vertical vibration, and in (d) point P ₁ moves to the left. The wave further progresses, moves to the right and downward, moves to the right and upward, and returns to the state of (a).
When this series of motions is combined, the point P ₁ has a spheroidal motion, and its radius of rotation is a function of t, where t is the length from the neutral surface 6 of the vibrating body 2 to the surface of the moving body. on the other hand,
The moving body 3 is in pressure contact with the vibrating body 2, and the spheroidal motion of the point P ₁ on the vibrating body 2 frictionally drives the moving body 3 in the X ₂ direction, as shown in FIG. The points P ₂ and P ₃ and all other points on the vibrating body 2 frictionally drive the moving body 3 in the same manner as the point P ₁ .

Conventionally, in the vibration wave motor driven by the above principle,
As shown in FIG. 3, the moving body has a contact portion 3c with a flange structure to have a spring property, and as shown in FIG. 4, the contact portion 3b has a resin to have elasticity, and The swell and the swell depending on the location of the traveling wave amplitude value were made to follow. However, in such a structure, the elasticity of the flange portion and the resin portion causes resonance of the system with the contact body 3a portion as a mass, which causes noise generation and output reduction.

<Objects of the Invention> The present invention has been made in view of such a situation, and an object thereof is to provide a vibration wave motor with high driving efficiency without noise by improving the structure of the contact body that contacts the moving body. It is what

<Example> The present invention will be described in detail below with reference to the drawings.

FIG. 5 is a sectional view of a moving body according to an embodiment of the present invention.

In FIG. 5, elements having the same mechanism as the elements shown in FIGS. 3 and 4 are designated by the same reference numerals and the description thereof will be omitted. 3d is an anti-vibration rubber, and 3e is an additional mass composed of metal or the like.

The principle of preventing the resonance generated in the contact portion 3c in this embodiment will be described with reference to the model of FIG.

In FIG. 6, m is the mass of the mass part 3e, and c and k are the vibration damping rubber 3d.
The damping constant, elastic coefficient, and M indicate the mass of the contact body 3a.

Here, in order to prevent the resonance generated in the contact portion 3c, the mass m of the mass portion 3e that satisfies the following equation, the damping constant of the vibration isolating rubber,
The elastic coefficient may be selected.

And (Omega: natural frequency, c _c: critical damping constant, zeta: damping ratio) contact by selectively so as to satisfy the above equation portions 3c
The vibration that occurs at is quickly absorbed and can be prevented from occurring.

As is clear from the above formula, the anti-vibration rubber 3d has an additional mass of 3e
Also, it has a larger damping constant and a smaller elastic coefficient than the contact body 3a.

FIG. 7 is a cross-sectional view of a vibration wave motor in which vibration is absorbed on the lower surface of the moving body. This structure also included in the present invention makes it possible to reduce the thickness of the vibration wave motor. Further, it goes without saying that the present invention also includes application to a linear reciprocating motion mechanism utilizing an oscillating wave.

<Effects of the Invention> As described above, according to the present invention, it is possible to prevent noise and a reduction in efficiency due to resonance of a contact body that contacts a vibration body of a vibration wave motor. 2 is a vibrating body, 3a is a moving body made of an elastic body, 3c is a contact portion of the moving body, 3d is a vibration damping material,
3e constitutes each of the additional mass members.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a main part of a vibration wave motor, FIG. 2 is a diagram for explaining the driving principle of the vibration wave motor, and FIGS. 3 and 4 are vertical cross-sectional views of a conventional moving body, and FIG. Is a sectional view of a vibration wave motor according to an embodiment of the present invention, FIG. 6 is a view showing a mechanical model of the present invention, and FIG. 7 is a sectional view of a vibration wave motor according to another embodiment of the present invention. 1 is an electrostrictive element, 2 is a vibrating body, 3 is a moving body, 3a is a moving body contacting body, 3b is a moving body contacting member, 3c is a moving body flange portion,
3d is an anti-vibration rubber, and 3e is an additional mass part.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuhiro Izugawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Hiroyuki Seki 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Hitoshi Mukaijima, 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Works (72) Inventor Naoya Kaneda, 770, Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. (72) Inventor Akira Hiramatsu, 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Plant (56) Reference JP-A-59-188381 (JP, A)

Claims (1)

[Claims] 1. A vibrating body that generates vibration and a contact portion that has elasticity and is formed to project so as to come into contact with the vibrating body are provided, and the vibration of the vibrating body is used as a driving force to move relative to the vibrating body. In a vibration wave motor having a contact body having a predetermined mass, an additional mass member having a predetermined mass and a vibration isolator are provided so that the contact body is not in contact with the vibration body. The vibration wave motor is characterized in that the vibration damping material is inserted between the additional mass member and the contact body.