JPH05122953A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To prevent an influence from being received due to speed and amplitude differences of an oscillatory wave between internal/external peripheries of a contact surface by enabling a bonding surface to sufficiently ensure its width of a rotor base material and a slider material, and preventing a stator from sticking to a rotor due to protruding of a bonding agent even when left alone for a long period. CONSTITUTION:A bonding surface of a slider material 2b to a rotor base material 2a is placed in parallel to a contact surface, in the contact surface P2 with a stator 1, and raised to rise upward to a rotor base material side from the contact surface in both ends. A width of the contact surface of the stator with a rotor 2 is set narrower than the width of the bonding surface of the slider material to the rotor base material and formed thin to a degree such as preventing an influence from being received due to speed and amplitude differences of an oscillatory wave between internal/external peripheries of the contact surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor which drives a rotor by generating progressive vibration waves in a stator.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a conventional example of an ultrasonic motor, and FIG. 8 is an enlarged sectional view showing a rotor portion of the conventional example motor shown in FIG. The stator 1 is composed of an elastic body 1a and a piezoelectric body 1b bonded to the elastic body 1a. By exciting the piezoelectric body 1b,
A progressive vibration wave is generated in the elastic body 1a.

On the other hand, as shown in FIG. 8, the rotor 2 is composed of a rotor base material 2a and a slider material 2b made of polyflon or the like which is adhered to the rotor base material 2a. When excited, a traveling wave having the same frequency as that of the stator 1 is generated. The stator 1 is connected to a support member 30 including a thin portion 31 and a flange portion 32, and the support member 30 is sandwiched between the fixing members 4 and 5.

When the rotor 2 is brought into pressure contact with the driving surface P1 of the elastic body 1a and an AC voltage (driving signal) is applied to the piezoelectric body 1b in this state, bending vibration is generated in the piezoelectric body 1b, and the elastic body 1a. A progressive vibration wave is generated on the driving surface P1 of the rotor 2, and the rotor 2 is driven by this vibration wave.

[0005]

However, in the above-described conventional ultrasonic motor, the slider material 2b is bonded to the rotor base material 2a only at the contact surface P2 contacting the drive surface P1 of the elastic body 1a. It was Therefore, unless the bonding surface between the rotor base material 2a and the slider material 2b is enlarged, the slider material 2b may peel off.

The thickness of the slider material 2b is 0.3 m.
Since it is as thin as about m, for example, when it is left for a long period of time, the adhesive may squeeze out from both ends of the slider material 2b and the stator 1 and the rotor 2 may be fixed to each other.

On the other hand, the rotor base material 2a and the slider material 2b
In order to secure the adhesive strength with
Since the velocity difference and the amplitude of the vibration waves are different between the inner and outer circumferences of the contact surface P2, torque unevenness may occur, and stable performance may not be obtained.

An object of the present invention is to ensure a sufficient width of the bonding surface between the rotor base material and the slider material, and to allow the adhesive to stick out to fix the stator and rotor when left for a long period of time, or to fix the inner and outer circumferences of the contact surface. It is an object of the present invention to provide an ultrasonic motor that can obtain stable performance without being affected by the difference in the velocity of the vibration wave and the difference in the amplitude.

[0009]

SUMMARY OF THE INVENTION An ultrasonic motor according to the present invention is provided with a stator that generates a progressive vibration wave in an elastic body when a piezoelectric body is excited, a rotor base material and the rotor base material and is bonded to the stator. In an ultrasonic motor comprising a slider material that is in pressure contact with a rotor that is driven by the progressive vibration wave, an adhesive surface between the slider material and the rotor base material is a contact surface that is a contact surface with the stator. And parallel to the rotor base material side at both ends.

Further, in the ultrasonic motor according to the present invention, the stator, which generates a progressive vibration wave in the elastic body due to the excitation of the piezoelectric body, is adhered to the rotor base material and the rotor base material and comes into pressure contact with the stator. In an ultrasonic motor including a slider material and having a rotor driven by the progressive vibration wave, a width of a contact surface between the stator and the rotor is larger than a width of a bonding surface between the slider material and the rotor base material. It is characterized in that it is narrow and thin enough not to be affected by the difference in velocity and amplitude of the progressive vibration wave at the inner and outer circumferences of the contact surface.

[0011]

According to the present invention, since both ends of the slider material are separated from the stator, the adhesive surfaces of the slider material and the rotor base material are not fixed by the protrusion of the adhesive. Further, when the width of the bonding surface between the slider material and the rotor base material is the same as the conventional one, the width of the contact surface can be small.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a sectional view showing a first embodiment of an ultrasonic motor according to the present invention, and FIG. 2 is an enlarged sectional view showing a rotor portion of the ultrasonic motor of the first embodiment.
FIG. 3 is a diagram showing the amplitude of a vibration wave that acts on each part of the elastic body. It should be noted that, in each of the embodiments described below, portions having the same functions as those of the above-described conventional example are designated by the same reference numerals.

The rotor 2 of the first embodiment has a rotor base material 2
The width of a is narrowed (for example, 1 mm or less), and both ends of the slider material 2b are bent and bent toward the rotor base material 2a side so as to cover both side surfaces of the rotor base material 2a.

Therefore, even if the contact surface P2 is made small, the adhesive surfaces have the same width and a sufficient adhesive force can be secured, and the slider material 2b does not fall off from the rotor base material 2a. Further, since both ends of the slider material 2b are raised, even if the rotor 2 is left in contact with the driving surface P1 of the elastic body 1a for a long period of time, the adhesive is prevented from sticking out and sticking.

Further, the contact surface P2 of the rotor 2 which is brought into pressure contact with the drive surface P1 of the elastic body 1a can be reduced, and the rotor 2 can be reliably driven near the maximum amplitude point T as shown in FIG. Therefore, stable performance can be obtained without being affected by the speed difference between the inner and outer circumferences, and the efficiency can be improved.

4 to 6 are sectional views partially showing second to fourth embodiments of the ultrasonic motor according to the present invention.
In the ultrasonic motor of the second embodiment, the rotor base material 2a has a substantially U-shaped cross section, and the slider material 2b is bonded onto the rotor base material 2a. The second embodiment is particularly effective when the contact surface P2 of the rotor 2 is not constant, such as when the pressing force structurally changes or when the difference in operating temperature is large.

In the ultrasonic motor of the third embodiment, the rotor base material 2a has a substantially V-shaped cross section, and the slider material 2 is formed on the rotor base material 2a.
b is bonded. The third embodiment is particularly effective when extremely stable performance is desired, such as when the rotor 2 is driven at the maximum amplitude T (see FIG. 3).

In the ultrasonic motor of the fourth embodiment, the rotor base material 2a has a substantially wedge-shaped cross section, and the slider material 2b is adhered thereon. The fourth embodiment is particularly effective when the width of the stator 1 in the radial direction is widened to form a motor having a large maximum torque.

That is, in the above-mentioned embodiment, since the contact surface can be made thin, there is no rotation unevenness, and especially the rotation speed at the low speed side is stable, and the rotation speed-current characteristic becomes linear and control is possible. It has the advantages of easier operation and longer battery life.

The present invention is not limited to the embodiment described above, and various modifications and changes can be made, which are within the scope of the present invention. For example, the cross-sectional shape of the bonding surface between the rotor base material and the slider material is
The curve is not limited to the above, and may be another curve such as an ellipse or a part of a hyperbola, and the width of the contact surface can be changed appropriately.

[0021]

As described above in detail, according to the present invention, even if the contact surface between the rotor base material and the slider material is made small, the width of the adhesive surface can be made large, so that a sufficient adhesive force can be secured. The slider material no longer falls off the rotor base material. Further, since the slider material is raised to the rotor base material side, even if the rotor is left in contact with the drive surface of the elastic body for a long time, the adhesive does not stick out and stick to it.

Further, since the contact surface of the rotor, which makes pressure contact with the drive surface of the elastic body, can be made small, stable performance can be obtained without being affected by the speed difference of the vibration wave at the inner and outer circumferences of the contact surface. It is possible to improve efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic motor according to the present invention.

FIG. 2 is an enlarged sectional view showing a rotor portion of the ultrasonic motor of the first embodiment.

FIG. 3 is a diagram showing the amplitude of a vibration wave acting on each part of an elastic body.

FIG. 4 is a sectional view partially showing a second embodiment of the ultrasonic motor according to the present invention.

FIG. 5 is a sectional view partially showing a third embodiment of the ultrasonic motor according to the present invention.

FIG. 6 is a sectional view partially showing a fourth embodiment of the ultrasonic motor according to the present invention.

FIG. 7 is a cross-sectional view showing a conventional example of an ultrasonic motor.

8 is a cross-sectional view showing an enlarged rotor portion of the motor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 1a Elastic body 1b Piezoelectric body 2 Rotor 2a Rotor base material 2b Slider material 30 Supporting member 31 Thin part 32 Flange part 4,5 Fixing member P1 Driving surface P2 Contact surface

Claims (2)

[Claims] 1. A stator that generates a progressive vibration wave in an elastic body when a piezoelectric body is excited, a rotor base material, and a slider material that is bonded to the rotor base material and is in pressure contact with the stator. In an ultrasonic motor having a rotor driven by an oscillating vibration wave, an adhesive surface between the slider material and the rotor base material is parallel to the contact surface at the contact surface with the stator, and the rotor from the contact surface at both ends. An ultrasonic motor characterized by being raised on the base metal side. 2. A piezoelectric body is excited to generate a progressive vibration wave in an elastic body, and a rotor base material and a slider material adhered to the rotor base material and in pressure contact with the stator. In an ultrasonic motor having a rotor driven by an oscillating vibration wave, a width of a contact surface between the stator and the rotor is narrower than a width of a bonding surface between the slider material and the rotor base material, 2. An ultrasonic motor characterized in that it is thin enough not to be affected by the difference in speed and amplitude of the progressive vibration wave.