JPH011482A - ultrasonic motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to ultrasonic morphs.

(Prior Art) In a conventional ultrasonic motor, for example, as shown in FIG. 3.4, a torsion transducer 2 is disposed on an ultrasonic transducer l with its leg portion 2a in contact with the ultrasonic transducer l. A rotor 3 is disposed on a beam-shaped protrusion 2C protruding from the disk portion 2b of the torsional vibrator 2, and the vibrator 2 is attached by a screw 4 passing through both 2 and 3.
There is one in which the rotor 3 is rotatably supported, and the rotor 3 is pressed against the torsional vibrator 2 by a spring 5. Then, the ultrasonic transducer l is the third
When vertically vibrated in the direction A in the figure, bending vibration occurs in the disk portion 2b of the torsional vibrator 2, and the disk portion 2b is vibrated in the direction B in the figure. 2C generates torsional vibration in the direction C in the figure, and as a result, the protrusion 2C of the torsional vibrator 2 is vibrated along an elliptical locus P, and the rotor 3 is rotated based on the vibration. There is.

(Problems to be Solved by the Invention) However, in the conventional ultrasonic motor, not only is the rotational direction of the rotor 3 limited to one direction, which is inconvenient, but also the rotation direction of the rotor 3 is limited to one direction. It is difficult to control motor characteristics such as rotational speed because it is difficult to change the ellipse locus (ratio of major axis to minor axis of the ellipse), and the ultrasonic transducer is large in order to generate longitudinal vibration in the direction of arrow A. turned into
There was a problem that the entire motor also became larger.

(Object of the Invention) This invention was made to solve the above problems, and its purpose is to easily control the motor by arbitrarily setting the rotational direction and rotational speed of the rotor. An object of the present invention is to provide an ultrasonic motor that can perform the following functions and can be made compact as a whole.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a vibrating piece is supported in a motor body so as to be able to vibrate, and vibrations in two different directions are generated independently on the vibrating piece. a plurality of ultrasonic vibrating elements that vibrate the vibrating element along an elliptical locus by the combined vibration thereof, and a rotor rotated by the vibration of the vibrating element is disposed in contact with the vibrating element. There is.

(Function) Therefore, according to the present invention, vibrations in two different directions are independently generated on the vibrating piece by the plurality of ultrasonic transducers, and the combined vibration of the vibrations in the two directions causes the vibrating piece to move along an elliptical trajectory. The rotor, which is placed in contact with the vibrating piece, is rotated. By adjusting the vibration phase of each of the ultrasonic transducers, the ratio of the major axis to the minor axis of the elliptical trajectory is changed, and the rotational direction, rotational speed, etc. of the rotor are controlled.

(Example) An example embodying this invention will be described below with reference to FIGS. 1 and 2.
This will be explained in detail according to the drawings.

A column-shaped support portion 12 is provided protruding from the inner surface of the bottom wall of the motor body 11 formed in a hollow shape, and an appropriate number of cantilever-shaped vibrating pieces 13 protruding to both sides are attached to the base end of the support portion 12. Each is fixed at A small piece 14 projecting to one side is integrally formed at the tip of each vibrating piece 13. 1 piece each
An ultrasonic vibrating element 15 made of a piezoelectric element is attached to the lower surface of the vibrating piece 13 at the base end of the ultrasonic vibrating element 13 , and bending vibration occurs in the vibrating piece 13 in response to an alternating current voltage applied to the element 15 .

Further, an ultrasonic vibration element 16 made of a piezoelectric element is attached to the lower surface of each small piece 14, and torsional vibration is generated in the vibrating piece 13 in response to the alternating current voltage applied to the element 16.

A rotor 18 is rotatably inserted into the screw 17 screwed into the support portion 12, and a ring-shaped contact portion 18 is provided on the outer peripheral edge of the rotor 18 to contact the upper surface of the tip end of each vibrating piece 13.
a is formed. Further, a spring 22 is interposed between the head 17a of the screw 17 and the rotor 18, and the rotor 18 is pressed against each vibrating piece 13 by the force of the spring.

An opening 19 is formed in the upper wall of the motor body 11 facing the support portion 12, and a hollow output shaft 20 is mounted on the upper surface of the rotor 18 so as to pass through the opening 19. The screw 17 is housed inside the output shaft 20, and the output shaft 20 is housed inside the opening 19.
A bearing 21 is installed for the purpose.

In the ultrasonic motor configured as described above, when a predetermined voltage is applied to each ultrasonic vibration element 15, 16 according to a preset phase, each ultrasonic vibration The vibration of the element 15 bends and vibrates each vibrating piece 13 in the direction of arrow R, and the vibration of each ultrasonic vibrating element 16 causes each vibrating piece 13 to vibrate torsionally in the direction of arrow S via each small piece 14. Due to the combination of re-vibration, each vibrating piece 13
is vibrated along an elliptical locus P shown in FIG. 2, and the rotor 18 and output shaft 20 are rotated together in a predetermined direction based on the vibration.

In this embodiment, since bending vibration and torsional vibration are generated independently in each vibrating element 13, by adjusting the phase of the voltage applied to each ultrasonic vibrating element 15, 16, the elliptical By changing the ratio of the major axis to the minor axis in the trajectory P, the rotational direction and speed of the rotor 18 can be easily controlled.

Note that the present invention is not limited to the above-mentioned embodiments, and it is also possible to use an electrostrictive element or a magnetostrictive element as the ultrasonic vibration element.

(Effects of the Invention) As detailed above, the present invention allows the motor to be easily controlled by arbitrarily setting the rotor's rotational direction, rotational speed, etc., and also allows the entire motor to be made compact. It exhibits an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of an ultrasonic motor embodying the present invention, and FIG. 2 is a partial side view showing a vibrating element. Fig. 3 is a partially exploded perspective view showing a conventional ultrasonic motor, and Fig. 4 is the same (plan view of the rotor).
゜16...Ultrasonic vibration element, 18...Rotor, P.
...Elliptical trajectory. Patent applicant Brother Industries Co., Ltd. Agent Patent attorney On 1) Hironori drawing No. 1 Fig. 3 Drawing No. 2

Claims (1)

[Claims] A vibrating piece (
13), and a plurality of ultrasonic vibration elements that independently generate vibrations in two different directions in the vibrating piece (13) and vibrate the vibrating piece (13) along an elliptical locus (P) by the combined vibration. (15, 16), arranged in contact with the vibrating piece (13), and the vibrating piece (13)
A rotor (18) rotated by the vibration of the ultrasonic motor.