JPS63224679A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To improve output efficiency by driving a piezoelectric vibrator conducting vibrations in the thickness direction or the longitudinal direction, generating flexural vibrations in a contact section and directly transmitting flexural vibrations to a rotor. CONSTITUTION:Three or more of protruding sections are formed to the surface brought into contact with a stator 2 in a piezoelectric vibrator 1 performing vibrations in the thickness direction or the longitudinal direction in an ultrasonic motor, and a shave-off section 4 is shaped to the side surface of the piezoelectric vibrator 1. A large number of protruding sections 6 are formed to the surface brought into contact with a rotor 5 in said stator 2 in the stator 2, and said rotor 5 is mounted under pressure by a machine screw 10 through a bearing 7, a washer 8, a spring 9, etc. Accordingly, when voltage is applied to the piezoelectric vibrator 1 and the piezoelectric vibrator is driven, the stator 2 conducts flexural vibrations by the protruding sections 3, and a vector is generated and the rotor 5 is turned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic motor that utilizes bending vibration.

(Prior Art) Ultrasonic motors using piezoelectric vibrators are being researched and developed, but their principles and structures vary. For example, an ultrasonic motor that uses elastic traveling waves to perform rotational motion,
As shown in FIGS. 13 and 74, when a plurality of piezoelectric vibrators 61 are attached to an elastic ring and the piezoelectric vibrators 61 are sequentially driven using signals with different phases, the elastic ring 62 has elasticity that performs elliptical motion. A traveling wave 63 is generated. This elliptical motion was used to rotate the rotor 64, which was brought into pressure contact with the elastic ring 62, but an ultrasonic motor with this configuration requires a large number of piezoelectric vibrators 61, and these piezoelectric vibrations The elements 61 must be driven with signals having different phases, which makes the drive circuit complicated and has to be increased in size. Further, since rotational motion is obtained using the elliptical motion of the elastic traveling wave 63 generated in the elastic ring 62, there is a problem in that the mechanical energy output is small relative to the input electrical energy and the efficiency is low.

(Problems to be Solved by the Invention) The present invention provides an ultrasonic motor that uses a piezoelectric vibrator that vibrates in the thickness direction or longitudinal direction, has a simple drive circuit configuration, has high output efficiency, and can be made compact. This is what we provide.

[Structure J of the Invention (Means for Solving Problems) The ultrasonic motor of the present invention includes a piezoelectric vibrator that vibrates in the thickness direction or the longitudinal direction, and a stator directly or on one or both surfaces of the piezoelectric vibrator. If necessary, a slit is provided on the surface of the piezoelectric vibrator or stator that contacts the rotor and/or the surface of the rotor that contacts the piezoelectric vibrator or stator.

Protrusions, protrusions, two-step recesses, or a combination of these may be provided, and slits and protrusions may be provided on the contact surface between the piezoelectric vibrator and the stator.

The rotor is provided with a convex portion, a one-step concave portion, or a combination thereof, and the rotor is rotated by driving a piezoelectric vibrator.

(Function) The ultrasonic motor of the present invention generates bending vibration in the stator or in the piezoelectric vibrator or the portion of the rotor that contacts the stator by driving a piezoelectric vibrator that vibrates in the thickness direction or in the longitudinal direction. Since the bending vibration is directly transmitted to the rotor, the efficiency of transmission to the rotor is increased.

(Example) Example 1 As shown in an exploded perspective view in Fig. 1 and an assembled view in Fig. 2, a piezoelectric vibrator 1 that vibrates in the thickness direction or longitudinal direction has 31! The piezoelectric vibrator 1 is provided with a cut-off portion 4 on its side surface, and a large number of protrusions 6 are provided on the part of the stator 2 that contacts the rotor 5. The rotor 5 is provided with a bearing 7, a washer 8 . It is attached to the stator 2 in a pressurized state with screws 10 via a spring 9 or the like.

In the ultrasonic motor having such a configuration, when a voltage is applied to the piezoelectric vibrator 1 to drive it, the stator 2 performs bending vibration because the three convex portions of the piezoelectric vibrator 1 are provided. Therefore, a vector moves on the convex portion provided on the stator 2, and the rotor 5 rotates thereby. Other examples of this stator 2 are shown in FIGS. 3 to 5, where 6a, 6b, and 6c are convex portions that contact the rotor, and as shown in FIGS. 4 and 5, the convex portions have a diameter It may be subdivided into a circumferential shape in one direction, a combination thereof, or an arbitrary shape.

Further, although FIGS. 6 to 8 show enlarged views of the contact portion of the convex portion provided on the stator with the rotor, a structure having a linear slope as shown in FIG. 6 as the contact portion 11a may also be used. ,
In this case, it was confirmed that when the stator is bent, the area in contact with the rotor can be increased, resulting in larger torque and superior transmission efficiency. In addition, as shown in FIG. 7, the contact portion 11b has a curved slope.

As shown in the eighth factor, the contact portion 11G may be made up of steps that are subdivided and have a slope. It is also possible to arbitrarily determine the rotational direction of the ultrasonic waves using a stator having such a slope. Furthermore, although it has been stated in FIG. 2 that the stator 2 is in contact with the rotor 5 at the convex portion 6, if the contact surface between the piezoelectric vibrator 1 and the stator 2 is uneven, the stator 2 and the rotor The contact portion with the rotor 5 may be a flat surface, or the rotor 5 may contact the protrusion 6 only when the piezoelectric vibrator 1 or the protrusion 6 of the stator 2 performs bending vibration.

Note that in the above embodiment, the piezoelectric vibrator 1 and the stator 2
Although it has been described that the piezoelectric vibrator 1 comes into contact with the stator 2 and the stator 2 contacts the rotor 5 by providing the convex portions 3 and 6 in the piezoelectric vibrator 1, the piezoelectric vibrator 1 comes into contact with the stator 2, and the stator 2 contacts the rotor 5. You may also do so.

Further, the piezoelectric vibrator 7 is provided with the cut-off portion 4, which has the effect of allowing the piezoelectric vibrator 1 to be used in a state where the degenerate mode occurring in the degenerate mode is separated.

Further, convex portions 3 are provided on both sides of the piezoelectric vibrator 1, and stators 2. Rotor 5. Bearing 7° Washer 8. Spring 9. The screw 10 may be used and a rotation mechanism may be provided at the upper and lower portions.

Embodiment 2 FIG. 9 shows an exploded perspective view of an ultrasonic motor, and FIG. 10 shows a plan view of a rotor. In other words, as shown in FIG.
Set the rotor 21 to the bearing 24. Washer 25. It is attached to the piezoelectric vibrator with a screw 27 via a spring 26 in a pressurized state. As shown in FIG. 10, the portion of the rotor 21 that contacts the piezoelectric vibrator 20 has a step 2
Four protrusions 22 having a diameter of 8 are provided at equal intervals. FIG. 11 shows another embodiment of a piezoelectric vibrator, in which a circumferential recess 29 is formed on the negative side, and the other components shown in FIG. 9 are used to construct an ultrasonic motor. Furthermore, as shown in FIG. 12, a slit 31 may be provided in a laminated piezoelectric vibrator 30 that vibrates in the thickness direction or in the longitudinal direction.

In this way, the shape of the piezoelectric vibrator is not limited to a circular shape, but a polygonal shape such as a quadrangular shape may be used.

In addition to the embodiments described above, slits, protrusions, convex parts, and four parts may be provided on the surface of the piezoelectric vibrator or stator that contacts the rotor and/or the surface of the rotor that contacts the piezoelectric vibrator or stator.

It may be possible to use a step consisting of a step or a combination thereof, or a contact portion may be further subdivided, a contact portion may have a slope, or a contact surface may be subdivided to have a step with a slope. . In addition, slits and protrusions.

The structure and shape of a structure consisting of a combination of a convex part, a one-step difference in a concave part, or a dot is not limited to each of the above individually described, but may be constructed from a combination of each as necessary, or may be subject to design changes. It is possible to obtain bending vibration even with a configuration that can be devised as appropriate, and the same effect as in the embodiment can be obtained.

Furthermore, slits are provided on the contact surface between the piezoelectric vibrator and the stator.
The ultrasonic motor may be provided with a protrusion, a convex portion, a two-step recess, or a combination thereof, or may be configured using a piezoelectric vibrator with a portion or several portions of the side surface shaved off. good. Note that the piezoelectric vibrator that vibrates in the thickness direction J5 and in the longitudinal direction may be of a laminated type, and in this case, it is possible to lower the voltage and make the piezoelectric vibrator smaller.

The drive signal for the piezoelectric vibrator may be not only an alternating current signal but also a pulse signal. In addition, the contact portion of the piezoelectric vibrator with the rotor, and/or the contact portion of the rotor or stator with the rotor, and/or the rotor may be made of rubber, other materials, valves, polymeric materials, or composite materials containing these. An ultrasonic motor may be constructed by attaching materials.

[Effects of the Invention] According to the ultrasonic motor of the present invention, a single-phase drive signal can be applied to a piezoelectric vibrator that vibrates in the thickness direction or longitudinal direction, without requiring a plurality of piezoelectric vibrators as in the past. This makes the structure simple and the circuit simple, and since direct bending vibration is used, the transmission efficiency from the piezoelectric vibrator to the rotor, or from the stator to the rotor, is very high.

[Brief explanation of the drawing]

1 to 12 show embodiments of the present invention, FIG. 1 is an exploded perspective view of an ultrasonic motor, FIG. 2 is a front view of the ultrasonic motor, and FIGS. 3 to 5 show the stator and other components. 6 to 8 are partially enlarged front views showing each embodiment of the contact portion between the stator and the rotor, and FIG. 9 is a plan view showing each of the stators according to another embodiment. An exploded perspective view of a sonic motor, and FIG. 10 is a front view of a rotor according to another embodiment.
11 and 12 are perspective views showing piezoelectric vibrators according to other embodiments, FIG. 13 is an exploded perspective view showing a conventional ultrasonic motor, and FIG. 14 shows the configuration of a conventional ultrasonic motor. FIG. 1... Piezoelectric vibrator, 2... Stator, 3... Convex portion. 4...Shaving off part, 5...Rotor, 6...Convex part Applicant: Marukon Electronics Co., Ltd.7. Be'7so>2゛. No. and fig.

Claims (6)

[Claims] (1) An ultrasonic motor comprising: a piezoelectric vibrator that vibrates in the thickness direction or in the longitudinal direction; and a rotor that contacts one or both surfaces of the piezoelectric vibrator directly or via a stator. (2) Provide slits, protrusions, protrusions, recesses, steps, or a combination thereof on the surface of the piezoelectric vibrator or stator that contacts the rotor, and/or the surface of the rotor that contacts the piezoelectric vibrator or stator. An ultrasonic motor according to claim (1), characterized in that: (3) Claim No. 1 characterized in that a contact surface of either or both of the piezoelectric vibrator and the stator is provided with a slit, a protrusion, a projection, a recess, a step, or a combination thereof. The ultrasonic motor according to item (1) or item (2). (4) Claims (1) to (3) characterized in that the side surface of the piezoelectric vibrator is partially or severally shaved off.
The ultrasonic motor described in any of the paragraphs. (5) The surface of the piezoelectric vibrator or stator that contacts the rotor, or the surface of the rotor that contacts the piezoelectric vibrator or stator has a slope. The ultrasonic motor according to any of item 4). (6) The ultrasonic motor according to any one of claims (1) to (5), wherein the piezoelectric vibrator is of a laminated type.