JPH0634599B2 - Vibration wave motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a configuration of a moving body of a vibration wave motor that frictionally drives the moving body with a progressive vibration wave.

[Background of the Invention]

A known example of a vibration wave motor driven by a progressive vibration wave, which has recently been put into practical use, will be described with reference to a fifth schematic diagram. In the figure, reference numeral 1 indicates electromechanical energy such as electrostrictive element, piezoelectric element, and magnetostrictive element. It is a conversion element, for example PZT (lead zirconate titanate). A vibrating body 2 is made of an elastic material, and the electrostrictive element 1 is adhered thereto. The vibrating body 2 is held on the stator (not shown) side together with the electrostrictive element 1. Reference numeral 3 is a moving body, and in this example, forms a rotor that is in pressure contact with the vibrating body 2. A plurality of electrostrictive elements 1 are adhered, and one group of them is bonded to the other group, and the other group is the wavelength λ of the vibration wave.
Are arranged at a pitch shifted by 1/4 wavelength. The electrostrictive elements in the group are arranged at a pitch of ½ wavelength so that the polarities of the adjacent elements are reversed.

In an oscillatory wave motor having such a configuration, when an AC voltage of Vo / SinωT is applied to one group of electrostrictive elements and an AC voltage of Vo / CosωT is applied to the other group of electrostrictive elements, each electrostrictive element Are oscillated by applying an AC voltage of 90 ° out of phase with each other in which two adjacent groups have opposite polarities. This vibration is transmitted, and the vibrating body 2 makes bending vibration according to the arrangement pitch of the electrostrictive elements 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 traveling states of the waves at this time are shown in FIGS. 6 (a) (b) (c) (d). Now, it is assumed that the progressive bending vibration wave proceeds in the X ₁ direction indicated by the arrow. 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. Cross section 7 ₁ orthogonal to the neutral plane 6
With regard, it is only in the line of intersection 5 ₁ of these two sides stress is vertical vibration not applied. At the same time, the cross section 7 ₁ oscillates to the left and right about the intersection line 5 ₁ . Section 7 ₂
Similarly, for 7 ₃ as well, left and right pendulum vibrations occur about 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. Considering the force acting on the point P by this pendulum vibration, when the line of intersection 5 ₁ is on the positive side of the wave (upper side of the center plane 0), a stress in the left direction (direction opposite to the wave traveling direction X ₁ ) is applied. , When it is on the negative side of the wave (also on the lower side), the stress in the right direction is applied. That is, the figure
At a (a), the relationship of the intersection line 5 ₂ and section 7 ₂ in a state when the former, applied the arrow direction of stress in the point P _2. Further, in the state where the relationship between the intersecting line 5 ₃ and the cross section 7 ₃ is the latter, stress is applied to the point P ₃ in the direction of the arrow. When the wave progresses and the intersection line 5 ₁ comes to the positive side of the wave as shown in (b), the point P ₁ moves leftward and at the same time moves upward. In (c), the point P ₁ is the top dead center of the vertical vibration and only moves to the left. Point P ₁ at (d)
Moves left and moves down. The wave further progresses and returns to the state of (a) through rightward and downward movements, rightward and upward movements.

When this series of motions is combined, the point P ₁ makes 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.
As shown in (c), the spheroidal motion of the point P ₁ on the vibrating body 2 frictionally drives the moving body 3 in the X ₂ direction. All the points P ₂ , P ₃ and other points on the positive side surface of the wave of the vibrating body 2 are point P.
_{As in the case of 1} , the moving body 3 is frictionally driven. By the way, in the vibration wave motor driven in this manner, the contact member of the moving body with the vibrating body is made of synthetic resin in terms of preventing vibration of the vibrating body and soundproofing and vibration isolation due to the vibration damping effect of the resin. However, on the other hand, the resin has a remarkable change in the physical property value due to the temperature change, and in particular, the change in the friction coefficient causes a change in the motor output due to the temperature.

[Object of the Invention]

The present invention has been made in view of the above points, and an object thereof is to employ a synthetic resin as a material of the contact member,
In addition, it is to provide a vibration wave motor that has little output fluctuation with respect to temperature changes.

[Outline of Invention]

Thus, the characteristic of the vibration wave motor according to the present invention made to achieve the above-mentioned object is that a moving vibration wave generated in the vibration body to which the electro-mechanical energy conversion element is bonded is brought into contact with the vibration body. In a vibration wave motor that drives a body, the surface of the moving body that comes into contact with the vibration body is formed by a combination of two or more kinds of synthetic resins, and the synthetic resin has a friction coefficient that increases as the temperature rises (hereinafter A combination of at least one type of resin (positive temperature dependency) and at least one type of resin whose friction coefficient increases with temperature decrease (hereinafter referred to as negative temperature dependency) is used. It is in a place where it is as small as possible.

In the above description, forming with a combination of two or more kinds of synthetic resins on the surface of the moving body means arranging two or more kinds of synthetic resins in a plurality of rows along the driving direction of the moving body, for example, two or more kinds in a circular moving body. When arranging the above synthetic resins in a concentric and different diameter circumferential arrangement, or dividing the surface of the moving body into a number of unit blocks along the driving direction of the moving body, each block has two or more types of synthetic resin. Is performed by arranging in combination.

Arrangement of two or more kinds of synthetic resins in the unit block may be performed in a row, a column, or any other suitable mode with respect to the driving direction of the moving body.

Examples of the synthetic resin whose friction coefficient has a positive temperature dependency used in the present invention include polyethylene and polypropylene. Similarly, examples of the synthetic resin having a negative temperature dependency include trifluoride resin, nylon 66, PTFE, polyoxymethylene and the like.

Examples of combinations of these synthetic resins having positive and negative temperature dependence include, for example, a combination of polyethylene and trifluoride resin, and a combination of polypropylene and nylon 66.

Example of Invention

Hereinafter, the embodiments shown in the drawings will be described in detail to clarify the constitution of the present invention.

FIG. 1 shows an embodiment of the present invention. Reference numeral 3a is a structure of a moving body, which is made of metal, resin, or the like. Four
b and 4c are synthetic resins that are bonded to the structure 3 and form a contact member that makes frictional contact with the vibrating body 2 described with reference to FIG. 3. Of these, 4b is, for example, polyethylene whose friction coefficient has a positive temperature dependence or polyethylene. First resin, polypropylene, 4c
Is a second resin whose friction coefficient has a negative temperature dependence, and which is made of, for example, a trifluoride resin (or nylon 66). In this example, a pair of these first and second resins form a unit block, and the change in average friction coefficient due to the temperature change as a whole is smaller than that when a single resin is used, and the temperature dependence of the friction driving force Has decreased.

In FIG. 2, the structure 5 in the moving body is made of resin, and the surface of this structure is coated with resin 5b, 5c. The relationship of the temperature dependence of the friction coefficient of the resins 5b and 5c is the same as in the case of FIG.

It should be noted that the present invention is not limited to the above-described embodiments, and for example, a vibration wave motor of a type that uses vibration waves to make a linear reciprocating motion by friction drive, three or more kinds of resins in a unit block on the surface of a moving body. , A vibration wave motor of the type in which two or more kinds of resins are circumferentially divided and arranged on the surface of the moving body as shown in FIG. 3, or
The present invention is also applied to a vibration wave motor of a type divided into a circumferential direction and a radial direction as shown in FIG.

〔The invention's effect〕

As described above, according to the present invention, the fluctuation of the motor output due to the temperature is reduced, and since resin is used for the contact surface, the noise reduction due to the vibration absorbing property and the abrasion of the surface of the vibrating body are also sufficiently reduced. And its usefulness is enormous.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a schematic structure of a moving body of an embodiment to which the present invention is applied, FIGS. 2, 3, and 4 are diagrams showing other embodiments, and FIG. 5 is a vibration motor. 6A, 6B, 6C, 6D, 6E, and 6D are diagrams for explaining the driving principle of the vibration motor. 1: electrostrictive element, 2: vibrating body 3,4,5: moving body, 4a, 5a: structural body 4b, 5b, 6b, 7b: first synthetic resin 4c, 5c, 6c, 7c: second synthetic resin

 ─────────────────────────────────────────────────── ─── 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 (72) Inventor Hitoshi Mukaijima, 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc., Tamagawa Works, Canon Inc. (72) Naoya Kaneda, 770, Shimonoge, Takatsu-ku, Kawasaki, Kanagawa Prefecture (72) Inventor Akira Hiramatsu 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. Tamagawa Plant (56) Reference JP-A-60-200778 (JP, A)

Claims (1)

[Claims] 1. In a vibration wave motor for driving a moving body in contact with the vibrating body by a progressive vibration wave generated in the vibrating body to which an electro-mechanical energy conversion element is joined, the moving body being in contact with the vibrating body. The surface of is formed by a combination of two or more kinds of synthetic resins, and these synthetic resins are a combination of at least one resin whose friction coefficient increases with temperature increase and at least one resin whose friction coefficient increases with temperature decrease. The vibration wave motor is characterized by minimizing the temperature dependence of the average friction coefficient indicated by the surface.