JPH01202174A - Two-dimensional vibration wave motor - Google Patents

Abstract

PURPOSE:To compactly increase a thrust force by combining longitudinal vibration resonance vibrators and a nonresonance longitudinal displacement element. CONSTITUTION:Longitudinal resonance vibrators A1...A2 are composed of PZT (lead titanate-zirconate) of one of electro-mechanical energy converter and aluminum or the like of the material having a small vibration attenuation. A nonresonance longitudinal displacement element (b) is formed by laminating PZT, and adhered to the vibrators A1...A2 by a coupling element (d). The mass point of the element (b) is combined to be vibrated at the contact with a moving element (c), thereby performing an elliptical motion. Thus, the element (c) can be easily frictionally driven in two-dimensional direction, thereby compactly obtaining a low speed and a large torque.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a two-dimensional vibration wave motor.

[Prior Art] For example, as described in Japanese Patent Application Laid-Open No. 58-148682, an electric-mechanical energy conversion element
Vibratory wave motors that excite traveling waves and frictionally drive moving objects have been put into practical use for camera AF;
If the amplitude of pushing up the moving object is A, then the speed of driving the object is kA (k is a constant value determined by the transducer cross-sectional shape, wavelength, and material constant), and in order to increase the driving speed, the pushing amplitude A must also be increased at the same time. Therefore, it is easy to generate sound, and in order to reduce the speed, the amplitude A is reduced, so the contact surface between the moving body and the vibrating body must be finished with high precision, and a hard material must be used to prevent waves from sinking. As a result, the variable speed range of the motor was narrow.

Therefore, for example, as described in Japanese Patent Application Laid-open No. 61-55012, bending vibrations are generated in two directions in a bar/shaped body, thereby deforming the bar/shaped body into a spiral shape, and the deformed body is It has been proposed to frictionally drive a movable body by rotating a rod-shaped body around its longitudinal axis.

[Problems to be Solved by the Invention] The vibration wave motor described in the above-mentioned Japanese Patent Application Laid-Open No. 61-55012 can independently vary the direction of pushing up an object and the amplitude I in the feed direction, so the speed variable range can be varied. However, since the mechanical quality factor Q of the vibrator is extremely high, strict machining precision is required to align the resonance frequencies of both vibrations, and even if the resonance frequencies are aligned initially, uneven pressure may occur. Since the amount of deviation of the resonant frequency due to changes in temperature and the like is different, there is a problem that ideal mass point motion cannot be achieved and efficiency is poor.

The present invention attempts to solve these problems. That is, an object of the present invention is to provide a two-dimensional vibration wave motor that has a wide variable speed range, is easy to manufacture, is compact, and can generate large thrust at low speeds. .

[Means for Solving the Problems] In order to achieve the above object, the two-dimensional vibration wave motor of the present invention includes a longitudinal vibration resonance vibrator driven by an electro-mechanical energy conversion element, and a J1 resonance longitudinal displacement element. It is assumed that three or more are combined and connected with an angle in each direction of displacement.

[Function] According to the present invention, by combining a longitudinal vibration resonant oscillator and a non-resonant longitudinal displacement element, it becomes possible to easily frictionally drive an object in two-dimensional directions, and obtain a large torque at low speed with a compact size. Is possible.

[Example code] FIG. 1 shows a first embodiment of the invention.

In Fig. 1, AI + A2 is a longitudinal vibration resonance oscillator, and a2+, a3 + aa, and a7 are lead zirconate titanate (PZ), which is a type of electro-mechanical energy conversion element.
T), and al + a4 + a5 + a6 are made of a material with low vibration damping, such as aluminum,
Each is joined or bolted together.

Further, b is a non-resonant longitudinal displacement element, for example, a layered PZT element is used. C is a moving body, and the contact surfaces of the non-resonant longitudinal displacement element and the moving body C are each subjected to wear-resistant treatment. A coupling member d is made of metal or resin with low vibration damping, and is connected to the longitudinal vibration resonant vibrators AI, A2 and the non-resonant longitudinal displacement element.

FIG. 2 shows the coordinate system of the two-dimensional vibration wave motor shown in FIG.

The operating principle of the two-dimensional vibration wave motor shown in FIG. 1 will be explained below.

Each axis passes through the center of the axis of the longitudinal vibration resonant transducer A, , A, and the non-resonant longitudinal displacement element, and the shaded area in FIG. 2 is the transducer A.
, , shows the longitudinal displacement when A2 is centrally supported and half-wavelength longitudinal vibration is excited.

The vibrator A1 is driven at a frequency ω1.

At this time, when the central part is restrained, the mass point in the connecting member d moves as follows, where A is the amplitude: x=A sin ω, t. On the other hand, the displacement element has a frequency ω,
When driving is performed with a 90° phase shift with respect to the X displacement at
When the coordinates are transformed so that = 0, the motion becomes z = B cosω1t with the amplitude as B.

Therefore, the mass point of the displacement element at the contact portion with the moving body C performs an elliptical motion due to the combination of both vibrations.

Therefore, the moving body C is frictionally driven in the X direction while repeating contact and non-contact. On the other hand, the direction of movement can be reversed by advancing or delaying the phase of the displacement element relative to the vibrator A1 by 90°. During this time, the vibrator A
1 is not energized and is bent and deformed in the X direction.

Next, when the vibrator A2 is driven at a frequency ω2 and the displacement element is driven at the same frequency ω2 with a shift of 90', and if the respective amplitudes are C and D, then at the contact part with the moving body C, , the mass point of the displacement element S performs an elliptical motion, and the moving body C is driven in the X direction.

In the above explanation, ω1≠ω2, but if the oscillators AI and A2 are designed so that ωl; ω2, simultaneous driving is also possible. In this case, driving in any direction on the xy plane is possible. It can be done smoothly.

FIG. 3 shows a second embodiment of the invention.

In FIG. 3, the electric-mechanical energy conversion element a2+
83+ aa + ay + alo+ a
ll+a14+ a15 is made of PZT, and the constituent materials of the vibrator are al, a4- a5. aa, aa + a
12+ a16 is made of aluminum.

The vibrator is located between the elements a2 and a3 and between the alo and al
1 is supported, and single-wavelength longitudinal vibrations, each of which is a vibration node, are excited. The same applies to the X direction.

In this way, by supporting on both sides, the bending rigidity is increased, and it is possible to press the moving body C against the non-resonant longitudinal displacement element more strongly than in the conventional case, and a stronger frictional force, that is, A large amount of thrust can be obtained.

In the above embodiment, the electric-mechanical energy conversion element aI
O+ a ll+ a 14+ a 1. is provided, but it may be omitted. Also, longitudinal vibration resonance oscillators A1 and A2
The angles formed by the two do not necessarily have to be right angles, and can be changed as necessary. However, since the movement of the movable body C is relative to the fixed body, conversely, the eight movable bodies C of the above embodiment may be fixed and used while the others are moved. Further, the roles of the longitudinal vibration resonant vibrators A, A2 and the non-resonant longitudinal displacement element may be reversed.

[Effects of the Invention] As explained above, according to the present invention, by combining a longitudinal vibration resonant vibrator and a non-resonant longitudinal displacement element, it is possible to easily frictionally drive an object in two-dimensional directions, and it is compact. At the same time, it becomes possible to obtain large thrust.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the first embodiment of the present invention, FIG. 2 is an explanatory diagram showing the friction system and vertical displacement of the vibrator of the two-dimensional vibration wave motor shown in FIG. 1, and FIG. FIG. 3 is a perspective view showing a second embodiment of the invention. A,, A2...Longitudinal vibration resonance vibrator a In a 4+ a S+ a 8+ a 9+
a 12+ a 16... vibrator constituent material a2+a3+a6+a7+alo+all+a14+a
I5...Electro-mechanical energy conversion element b...Non-resonant longitudinal displacement element C...Moving body d...Coupling member

Claims (1)

[Claims] 1. A longitudinal vibration resonant vibrator driven by an electro-mechanical energy conversion element and three or more non-resonant longitudinal displacement elements are combined, and are coupled at an angle in each displacement direction. A two-dimensional vibration wave motor characterized by: 2. The two-dimensional vibration wave motor according to claim 1, wherein a plurality of longitudinal vibration resonance oscillators are combined so that their displacement directions are perpendicular, and a non-resonance longitudinal oscillator is coupled in a direction perpendicular to a plane formed by both. 3. The two-dimensional vibration wave motor according to claim 1, wherein a plurality of non-resonant longitudinal displacement elements are combined so that their displacement directions are perpendicular, and a longitudinal vibration resonance vibrator is coupled in a direction perpendicular to a plane formed by both elements.