JP2625653B2 - Vibration wave motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved vibration wave motor driven by traveling vibration waves.

[0002]

BACKGROUND OF THE INVENTION The vibration wave motor generates a bending traveling wave on a diaphragm made of an elastic body by means of an electro-mechanical energy conversion element such as an electrostrictive element which is arranged along the traveling direction of a moving body, and vibrates by its driving force. FIGS. 5 and 6 show one example of a conventionally known device for driving a moving body placed on a plate. In the drawing, reference numeral 1 denotes a diaphragm made of an elastic body forming an oval closed loop, and 2 denotes an electrostrictive element. The electrostrictive element 2 is divided into two sets of A-phase and B-phase on each of the two linear portions of the diaphragm 1 and arranged with a phase difference of 波長 wavelength (λ / 4) as shown in the drawing. The phases are alternately joined at +/- intervals at [lambda] / 2. Reference numeral 3 denotes a moving body as a contact body pressed against the diaphragm 1, and reference numeral 4 denotes a support for the diaphragm.

The A-phase and B-phase electrostrictive elements 2, 2,.
When an alternating voltage having a phase difference of 0 ° is applied, a bending traveling wave is generated in the diaphragm 1, and the moving body 3 moves along the diaphragm 1 by a frictional force at a contact portion with the diaphragm 1. As described above, a linear drive type vibration wave motor has a straight portion and a circular arc portion, and the vibration mode when a standing wave is generated is more complicated than a simple circular or straight beam. Further, since the electrostrictive element 2 is joined to the diaphragm 1, the rigidity of the diaphragm is different from that of the other portions at the joining portion, so that the vibration mode is further complicated. For this reason, as described above, A / 4
Although the standing wave is created with the phase difference of the above, a shift such as the length of the wavelength occurs due to the above factors, and the position of the antinode of the standing wave of each phase and the center of the electrostrictive element 2 are shifted. The traveling wave obtained by superimposing these two standing waves has a non-uniform amplitude, and a disadvantage in the performance of the motor cannot be avoided.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the drawbacks of the prior art and to efficiently transmit vibration energy to a vibrating body to effectively extract a diaphragm amplitude, thereby obtaining a traveling wave having a uniform amplitude. An object of the present invention is to provide an improved vibration wave motor.

[0005]

SUMMARY OF THE INVENTION A configuration for realizing the object of the invention according to the present application
Is an oblong vibrating body having a linear portion and an arc portion,
Two sets of electro-mechanical energy that are shorter than the circumference of the body
-By joining the conversion element group, at least
Providing a non-joining region of the electro-mechanical energy conversion element group,
The progressive vibration wave generated in the vibrating body by the element group
The contact body on the vibrating body and the contact body are linearly moved relative to each other.
The two sets of electro-mechanical energy
All individual electro-mechanical energies of the energy conversion elements
The center of the conversion element, the standing wave of each set generated in the vibrating body
Is substantially matched with the position of the belly .

[0006]

FIG. 1 shows a configuration of a stator in an embodiment of a vibration wave motor according to the present invention. In FIG. 1, reference numeral 1 denotes a diaphragm as a vibrating body and 2 denotes an electrostriction as an electromechanical energy conversion element. Element. When an alternating voltage is applied to the electrodes on the front and back of one electrostrictive element 2, the electrostrictive element 2 expands and contracts.
Vibrates so that the center of the electrostrictive element 2 becomes the antinode of the standing wave. The standing wave of the elliptical diaphragm 1 is shown in FIG.
(A) As shown in (b), the diaphragm has a vibration characteristic in which nodes are formed at symmetrical positions with respect to the center axis of the diaphragm. Therefore, FIG.
(A) When the electrostrictive element is joined to the diaphragm so that the antinode position of the vibration mode of each standing wave shown in (b) is aligned with the center of each electrostrictive element, efficient excitation can be achieved.

When the electrostrictive element 2 is joined to the diaphragm 1, the rigidity of the joint changes, so that a vibration having a uniform wavelength as shown in FIGS. 3A and 3B cannot be obtained. In the straight portion on the side where the element is not joined, uniform vibration is obtained with little influence of these. Therefore, as shown in FIG. 1, an A-phase is formed on the surface of the straight portion on one side, and the λ /
When the B phase is formed with a phase difference of 4, a traveling wave having the same amplitude can be obtained in the other linear portion. Further, in order to make the rigidity of the entire stator symmetrical with respect to the central axis S ′, B
The phases wipe the electrostrictive element at the center as shown.

[0008] With the above construction, the phase A and the phase B
The driving frequencies of the phases match well, and efficient driving is possible.

FIG. 4 shows another embodiment according to the present invention. In this embodiment, the diaphragm 1 has a rectangular cross-sectional shape whose height is higher than the width, and the electrostrictive element 2 is joined to both side surfaces of one straight portion of the diaphragm 1 with a phase difference of λ / 4. .
An alternating voltage having a phase difference of 90 ° is applied to each of the A phase and the B phase, and a traveling wave is generated in the diaphragm 1 in the direction of arrow A in FIG. 3
Is driven in the arrow direction B.

In the description of this embodiment, the element to be joined to the diaphragm is an electrostrictive element, but may be any other electro-mechanical energy converting element such as a magnetostrictive element or a piezoelectric element.

[0011]

As described above, according to the present invention,
An elliptical vibrating body having a linear portion and an arc portion
Two sets of electro-mechanical energy changes that are shorter than the circumference
By joining the exchange element group, at least the electric
Providing a non-bonding region for the mechanical energy conversion element group,
Vibration generated by the vibrating body
The contact body on the moving body is linearly moved relative to the contact body
In an oscillatory wave motor, the two sets of electro-mechanical energy
-All individual electro-mechanical energy conversion of the conversion elements
The center of the element is positioned at the antinode of each set of standing waves generated in the vibrator.
The following effects can be obtained
Can be

1. Vibration energy can be efficiently transmitted to the vibrating body.

2. By the above 1, the vibration body amplitude can be effectively taken out.

3. A traveling wave with uniform amplitude is obtained.

[0015] The difference in drive frequency between the two sets of electromechanical energy conversion elements can be reduced.

[Brief description of the drawings]

FIG. 1 shows a configuration diagram of a stator in an embodiment of a vibration wave motor according to the present invention.

FIG. 2 shows the principle of vibration wave generation.

3 (a) and 3 (b) show out-of-plane bending vibration modes of two types of standing waves of an oval diaphragm.

FIG. 4 shows another embodiment according to the present invention.

FIG. 5 is an external view of a conventional vibration wave linear motor and a stator configuration diagram of the motor.

FIG. 6 is an external view of a conventional vibration wave linear motor and a stator configuration diagram of the motor.

[Explanation of Signs] 1: Oval diaphragm 2: Electrostrictive element 3: Moving body 4: Vibration-proof support

Claims (1)

(57) [Claims] To 1. A oblong vibrator having a straight portion and an arc portion, two sets of electric to be shorter than the circumferential length the length of the vibrator - by joining the mechanical energy conversion element groups, small
At least the non-joining area of the electro-mechanical energy conversion element group
The band is provided, in the vibration wave motor linearly moved relative to the contact body and the contact body on the vibrating body by traveling vibration waves generated in the vibration member by the element group, said two sets of electrical - mechanical All of the energy conversion elements
A vibration wave motor, wherein the center of each of the electro-mechanical energy conversion elements substantially coincides with the position of the antinode of each set of standing waves generated in the vibrating body.