JPH056428B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an ultrasonic motor that utilizes ultrasonic vibrations.

(Background of the Invention) Motors that utilize electromagnetic force, which have been the most commonly used motors in the past, have significant restrictions on shape and materials, and are structurally difficult to use, such as wire windings and the need to achieve high output with a small size. However, there were limitations in terms of cost, such as the use of rare earth permanent magnets.

In response to this situation, actuators have been developed to replace conventional electromagnetic motors, and one type of actuator is a motor that uses ultrasonic vibration. As a prototype example of a motor that utilizes ultrasonic vibrations (hereinafter referred to as an ultrasonic motor), a surface wave is generated on the surface of an elastic material using a piezoelectric material, etc., and a surface that drives a rotor that is pressed against this surface. A wave-type ultrasonic motor (hereinafter referred to as a surface wave motor) has been devised.
And as this surface wave type ultrasonic motor,
There is one in which the surface of the elastic body is a rotationally symmetrical surface (for example, a cylindrical surface or a conical surface), and the pressure contact surface of the rotor that is pressed against the rotationally symmetrical surface is formed along this rotationally symmetrical surface.

However, the conventional device has a drawback in that it is difficult to press the pressure contact surface of the rotor against the rotationally symmetrical surface of the elastic body evenly over the entire circumference of the rotationally symmetrical surface.

(Object of the Invention) The present invention solves these drawbacks and provides an ultrasonic motor that can press the pressure contact surface of the rotor evenly over the entire circumference against the rotationally symmetrical surface (for example, a cylindrical surface or a conical surface) of an elastic body. The purpose is to provide.

In this specification, the term "rotationally symmetrical surface" refers to a surface formed by a straight line or curved line when the straight line or curved line is rotated about one axis. Examples of rotationally symmetrical surfaces include cylindrical surfaces, conical surfaces, and spherical surfaces.

(Embodiment) Fig. 1 shows an embodiment of the present invention, in which the driving side is divided into a cylindrical elastic body 1 and a plurality of regions (15 regions in the embodiment), and a high voltage is applied to each region. A piezoelectric body 2 for exciting the elastic body 1 and an electrode 3a for applying a voltage to the piezoelectric body, both of which have been equally polarized.
~3c, and a conductive wire 4a provided corresponding to each electrode.
4c and terminals 5a to 5c.
The stator is composed of an elastic body 1 and a piezoelectric body 2. The voltage body 2 has each electrode 3 inside the elastic body 1.
A to 3c are provided inside the piezoelectric body 2, respectively. Further, as shown in FIG. 1, the rotor 6 on the driven side includes a cylindrical base 6a and a plurality of branch-shaped parts (three in this embodiment) 6b to 6b extending from the base 6a.
6d, and pressure contact surfaces 6e' to 6e' shaped along the outer periphery of the elastic body 1 formed at the tips of the branch parts 6b to 6d.
It consists of pressure contact parts (contactors) 6e to 6g having a diameter of 6g' and a ring-shaped pressure member 7. Each branch 6b~
The tip of 6d (the side where the pressure contact portion is provided) is configured to expand outward due to its own elastic force.
Further, the pressure contact portions 6e to 6g are configured to have freedom in the pressure contact direction component and move independently due to the elastic force of the branch portions 6b to 6d. Screws 6h to 6j are formed on the outer periphery of the root portion of each branch. A screw 7a is formed on the inner periphery of the pressure member 7 and is screwed into each of the screws 6h to 6j. Therefore, when the screws 6h to 6j and the screw 7a are screwed together and the pressurizing member 7 is rotated, the pressurizing member 7 rotates the respective branch-like portions 6b to 7a.
6d and progresses toward the tip of each branch. Each pressure contact portion 6e to 6g is displaced inwardly. Strain each pressure contact surface 6e'~
6g' is pressed onto the outer peripheral surface of the elastic body 1 with an even force.

Now, when the terminal 5b is grounded and a high frequency sine wave is applied to the terminal 5a and a sine wave out of phase with the sine wave (for example, 90 degrees) is applied to the terminal 5c, the elastic body is 1 is excited, and a surface wave is generated on the surface of the elastic body 1 (outside the cylinder). Therefore, the pressure contact portions 6e to 6g pressed to the outside of the elastic body 1 are driven on the elastic body 1 in the circumferential direction thereof. In this way, the rotor 6 rotates on the elastic body 1 in the circumferential direction.

In this embodiment, the pressure contact parts 6e to 6g are pressed onto the elastic body 1 separately and independently as described above.
The axis of the rotationally symmetrical surface of the elastic body 1 (the axis of the cylinder constituting the elastic body 1) and the rotational axis of the rotor 6 may be configured to completely match, or the rotationally symmetrical surface of the elastic body 1 may be configured to be completely rotationally symmetrical. In other words, each pressure contact portion 6e to 6g does not require such strict manufacturing precision.
can be pressed against an elastic body with even force. Therefore, smooth rotational force can be transmitted.

Furthermore, with the configuration as in this embodiment, it is easy to adjust the pressing force of the pressure contact portion against the elastic body 1.

Furthermore, if the rotation of the pressure member described in this embodiment can be controlled, the elastic body 1 and the pressure contact portion 6e
It is possible to control contact of up to 6 g, and the pressure member and rotor 6 can also have a clutch function.

In addition, in this embodiment, a pressure contact portion 6e is provided outside the elastic body 1.
Although the piezoelectric body 2 and the electrodes 3a to 3c are provided outside the elastic body, it goes without saying that the piezoelectric body 2 and the electrodes 3a to 3c may be provided inside the elastic body, and a press-contact portion pressed therewith may be provided inside the elastic body.

Further, the principle of the surface wave motor used in this embodiment is described in detail in "Nikkei Mechanical" dated February 28, 1983, and will not be described in detail.

(Effects of the Invention) As described above, the present invention provides an ultrasonic motor that can apply pressure force between the elastic body and the rotor evenly over the entire circumference without requiring high manufacturing precision. Obtainable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention. [Explanation of symbols of main parts], 1...Elastic body, 2
... Piezoelectric body, 3a to 3c... Electrode, 6... Rotor, 6e' to 6g'... Pressure contact surface.

Claims (1)

[Claims] 1. An ultrasonic motor comprising a stator 10, a rotor 6, and a pressure means 7, wherein the stator 10 includes an elastic body 1 having a shape forming a rotationally symmetrical surface, and an elastic body 1 having a shape forming a rotationally symmetrical surface. The rotor 6 consists of a piezoelectric body 2 that vibrates, and the rotor 6 is divided into a plurality of parts along the circumferential direction, each having a contactor 6e having pressure contact surfaces 6e' to 6g'.
~6 g, and has a degree of freedom in the direction of pressure with respect to the elastic body 1 and moves independently. An ultrasonic motor that holds pressure.