JPH0532991B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic motor useful as a drive device in various fields.

(Prior Art and its Problems) Most of the various motor devices that have been widely used in the past utilize electromagnetic force as their driving source, and are used for various purposes. However, the size, weight, rotational force, etc. of these devices are limited by the magnetic properties of the materials used, and there are also limits to their compact size and light weight.

On the other hand, as an alternative to these conventional motors, the present applicant has developed a motor device that uses ultrasonic vibrations, that is, an ultrasonic vibrator that uses vibration waves excited on the surface of an elastic body. A device has already been proposed that converts the motion of a moving body into pressure contact with the body.

This motor device converts the powerful vibrational energy of ultrasonic waves into rotational or linear motion.

This ultrasonic vibration motor has unprecedented features and can be made smaller and lighter, making it extremely useful for applications in various fields. However, despite its characteristics, there were some points that needed to be improved in order to realize it. For example, the flatness of parts that have been cut or ground generally has an error of about 0.01 mm to 0.1 mm, so the surface of the mover, which is made of a material close to a rigid body, is pressed against the surface of the stator that has such a flat surface. Even if they are brought into contact, from a microscopic perspective, the surface roughness of each component is similar to the horizontal vibration axis a in Figure 1, which shows the operating principle of a motor, and it is not possible to contact them with uniform pressure, resulting in a drive failure. The disadvantage was that the force transmission effect was significantly impaired. Therefore, in the past, it was necessary to finish the stator surface together with the rotor surface into an ultra-precise flat surface.

(Means for Solving the Problems) This invention has been made in order to eliminate the above-mentioned drawbacks, and as a means for that purpose,
An ultrasonic motor having a stator and a movable element, where the stator is excited and generates a traveling wave on its surface, the movable element has an elastic body and a slider, and the slider has an elastic body. is formed on or integrally with the surface of the stator, and is in contact with the stator,
The present invention provides an ultrasonic motor in which a movable element is movable relative to a stator.

In other words, this invention efficiently generates a large driving force by driving the slider by uniformly pressing the slider into contact with the stator surface, which has an imperfect flat surface due to general machining. The present invention provides an ultrasonic motor device that eliminates the need for this work.

The operating principle and embodiments of the motor device of the present invention will be described below with reference to the drawings.

(Function) FIG. 1 is a partially enlarged perspective view for explaining the principle of operation. This is an enlarged view showing a state in which a traveling wave, which is a vibration wave that is a combination of transverse vibration and longitudinal vibration, is formed on the surface 1a of a stator 1 made of metal or the like.

Moreover, this FIG. 1 shows the propagation state of a traveling wave (the vibration source is not shown). That is, when focusing on mass point B, a wave that is a combination of horizontal amplitude a (vertical direction) and vertical amplitude b (horizontal direction) is moving on ellipse Q in the direction of arrow M, and the wave has a velocity U. moving at speed. This movement is the same at any point on the stator surface 1a, and when the free movable element 2 is brought into pressure contact with the surface of the stator 1 under this condition, this movable element 2 moves onto the stator 1. crest A of the wave and
contact only at part A', and these vertices A,
Since A' is moving in the direction of arrow M at the vibration speed V = 2πfb (where f is the frequency), the free mover 2 is driven in the direction of arrow N by the frictional force with stator 1. will be done.

Therefore, in order to increase the mechanical driving force (rotational force or propulsive force) of the mover 2 while keeping the electrical input constant, first increase the pressurizing contact force, and at the same time make the many vertices of the wave uniform with the moving body surface. Make contact with pressure.

However, the movable element 2 receives high-frequency vibration pressure from the surface of the stator 1, and vibration displacement occurs in the normal and tangential directions due to elastic deformation. In particular, displacement of the movable element 2 in the tangential direction greatly reduces the speed of the moving body.

Therefore, the conditions that can be considered for the mover 2 are that it always follows the surface of the stator 1, which has an imperfect surface, that it has a mass that has sufficient inertial resistance in the high frequency vibration band, and that it has elasticity in the normal direction. It is possible to increase the elastic body in the tangential direction with respect to the modulus.

From this point of view, in the present invention, the movable element 2 has an elastic body and a slider, and the slider satisfies the conditions that the movable element 2 should have, and the movable element 2 performs rotational, linear movement, etc. be integrated as one.

(Examples) Example 1 (Slider divided into small pieces) In FIG. 2, the surface of the stator 1 made of an elastic body such as metal has an incomplete plane 1A. Therefore, in order to sufficiently follow this plane 1A, in the present invention, the movable element 2 is integrated with the slider 5 divided into small pieces, an elastic body 3 made of rubber, for example, and a support 4 for applying pressure to the slider 5. It is structured according to Here, the slider 5 has a mass having sufficient elastic resistance in a high frequency band.

Example 2 (Slider with anisotropy) Also in the example shown in FIG. 3, the surface of the stator 1 has an incomplete plane 1A. The movable element 2 composed of a support 4 and a slider 5 is brought into pressure contact with this plane 1A. Here, slider 5 has
The high elastic modulus member 5B is embedded in the tangential direction inside the low elastic modulus member 5A to provide anisotropy in the elastic modulus in the normal direction and the tangential direction. That is, this slider 5 is integrated with the elastic body 3. especially,
Using piano wire as the fiber has a large elastic mass and is extremely effective.

Example 3 (Flexible slider) Also in the example shown in FIG. 4, the surface of the stator 1 has an incomplete surface 1A. This side 1A
An elastic body 3 having a low elastic modulus is arranged between the support body 4 and a flexible plate-like member 6 corresponding to the slider 5, for example, a plate having a high elastic modulus such as a steel plate, and It is integrally constructed as the movable element 2.

Embodiment 4 (Rotary motor) FIG. 5 shows a cross-sectional view of an example of a rotary motor.

The rotary movable element 2 has a slider that contacts the stator 7 and a spring 8, and is connected to a shaft 9. The motor also includes a bearing 10 and an acoustic insulator 11. In other words, a slider divided into small pieces in the circumferential direction is pressed into contact with the stator 7 having an incomplete plane. Each individual slider is maintained by a plurality of springs 8, and the springs 8 are fixed to a shaft 9.

(Effects of the Invention) As is clear from the above description, the present invention achieves high efficiency by employing a rotor or a mover that contacts the stator surface having an imperfect plane with uniform pressure. This is extremely useful in terms of generating strong driving force. Furthermore, the flat surface machining accuracy of the stator surface does not require ultra-precision machining, and general machining conditions are sufficient, and a large cost burden can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged perspective view showing the operating principle of an ultrasonic motor, and FIGS. 2 to 5 are a partially enlarged perspective view and sectional view showing an embodiment of the present invention. 1... Stator, 1a... Stator surface, 1A...
Plane, 2...Mover, 3...Rubber-like elastic body, 4...
... Support body, 5 ... Slider, 5A ... Low elastic modulus member, 5B ... High elastic modulus member, 6 ... Plate member (slider), 7 ... Stator, 8 ... Spring, 9 ... Shaft , 10... Bearing, 11... Acoustic insulator.

Claims (1)

[Claims] 1. An ultrasonic motor having a stator 1 and a movable element 2, in which the stator 1 is excited and generates a traveling wave on its surface, and the movable element 2 is made of an elastic body. 3 and a slider 5, the slider 5 has an elastic body 3
An ultrasonic motor that is formed on the surface of or integrally with the stator 1 and is brought into contact with the stator 1 so that the movable element 2 is movable relative to the stator 1. 2. The ultrasonic motor according to claim 1, wherein the elastic body 3 of the movable element 2 has an elastic modulus that has different directions with respect to the tangential direction and the normal direction of its surface.