JPH02155480A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To reduce the outside diameter of an ultrasonic motor by obliquely projecting a plurality of supporters at a regular interval in the direction of motion of a moving body to a support member and holding the moving body or a stator by the supporters. CONSTITUTION:The supporters 3a of a stator support member 3 are projected obliquely at a certain inclination in the direction of motion of a rotor 2. Supporters 20a are projected integrally at a certain inclination in the direction of motion of the rotor to a rotor base material 2a. When the AC voltage of specified frequency is applied to the piezoelectric body 1b of a stator 1, the piezoelectric body 1b is excited, and progressive waves are generated in the driving surface 1c of an elastic body 1a. Since the rotor 2 is pressured and brought into contact with the driving surface 1c by a pressure member 6, it is friction-driven by progressive waves generated in the elastic body 1a and turned. Accordingly, the stator support member 3 and the outside diameter of a rotor support member 20 can be made smaller than conventional devices only by the inclination sections of each supporter 3a, 20a of the members 3 and 20.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an ultrasonic motor that drives a moving element such as a rotor using progressive vibration waves generated in an elastic body by a piezoelectric body.

B. Conventional technology A progressive vibration wave type ultrasonic motor is disclosed in Japanese Patent Application Laid-Open No. 59-111.
As disclosed in Japanese Patent No. 609, an alternating current voltage is applied to a piezoelectric body to cause bending vibration in the piezoelectric body, and a progressive vibration wave is generated in an elastic body to which the piezoelectric body is attached. This is a friction-driven motor that brings the slider into pressure contact with the slider.

In such an ultrasonic motor, since the stator vibrates while being indirectly subjected to pressure by the movable element, there is an impact effect between the stator and the fixed member that fixedly supports the stator, such as felt. A support member was interposed. But with a structure like this.

This is because the buffer member is in contact with almost the entire surface of the stator.

Attenuates stator vibration and reduces efficiency. In other words, the support performance is low. In addition, due to the characteristics of materials that have a buffering effect,
Problems arise such as difficulty in positioning and deterioration of the material due to aging. Furthermore, with regard to the movable element which is vibrated by the excitation of the stator, the same problem as that of the stator occurs with respect to the structure of its support member.

In order to solve these problems, a support method that supports the vicinity of the neutral axis of vibration in the stator and minimizes the attenuation of vibration of the stator is proposed, for example, in JP-A-62-147974 and JP-A-60. No.-96183, JP-A-62-77068
It is disclosed in the official gazette such as No.

FIG. 4 shows a perspective view of a rotary ultrasonic motor using such a support method.

The elastic body 1a and the piezoelectric body 1b are integrally bonded to form the stator 1, and a traveling wave is generated on the surface thereof by a drive control circuit (not shown). On the other hand, the rotor 2 is formed of a rotor base material 2a and a slider material 2b, and is pressed into contact with the stator 1 by a pressure member (not shown).

The stator support member 13 has elasticity and has an annular body 13b.
Supporters 13a protruding inward in the radial direction are provided at regular intervals in the circumferential direction, and in a number that is an integral multiple of the wave number of the stator traveling wave. Its shape is shown in FIG. The supporter 13a is bonded to the lower surface of a flange portion 1c provided on the outer circumference of the elastic body 1a. And the support member 13
is fixed to a fixing member (not shown) by its annular main body 13b.

The rotor 2 includes a rotor support member 12 consisting of a rotor base material 2a, a supporter 12a integrated with the rotor support member body 12b, and a rotor support member body 12b.
Supported by Like the stator support member 13, the rotor supports 12a are elastic, extend in the radial direction at equal intervals around the circumference, and are provided in a number that is an integral multiple of the wave number of the traveling wave generated in the stator 1. ing.

The flange portion 1c, which is a support portion of the stator 1, has an elastic body 1
The stator 1 is provided near the neutral axis of the stator 1, which is made up of a piezoelectric member 1a and a piezoelectric member 1b. Also, a rotor supporter 1 supporting the rotor 2
2a is also provided near the neutral axis of the rotor base material 2a that constitutes the rotor 2.

Therefore, the attenuation due to support of the traveling wave generated in the stator 1 and the traveling wave excited by the stator 1 and generated in the rotor base material 2a can be suppressed to a minimum.

Furthermore, the positioning accuracy of the stator is improved compared to the above-mentioned felt support.

C6 Problems to be Solved by the Invention However, in such conventional ultrasonic motors, the stator 1 or the rotor 2 is supported by supports 13a and 12a that protrude in the radial direction. There was a problem in that the diameter became large, which was disadvantageous when mounting it on a product.

A technical object of the present invention is to reduce the outer diameter of an ultrasonic motor without causing a reduction in driving efficiency due to attenuation of traveling waves of a stator or a moving element.

To explain with FIG. 1 and FIG. 2 showing an example of means for solving the problem,
The present invention includes a stator 1 that generates progressive vibration waves in an elastic body 1a by excitation of a piezoelectric body 1b, and is fixed to a stationary side by a first support member 3; The present invention is applied to an ultrasonic motor that includes a moving element 2 that is driven by a magnetic vibration wave and is fixed to the driven side by a second support member 20.

The above technical problem is solved by the following configuration.

The first and/or second support members 3, 20 have a plurality of supports 3a, 2QB that project diagonally at predetermined intervals with respect to the movement direction of the mover 2, and these supports 3a,
The mover 2 or stator 1 is held by 20a.

80 action The supports 20a or 3a that support the mover 2 or the stator 1 are provided to protrude obliquely to the moving direction of the mover 2, and these supports have the same length as the conventional ones. Since it has a certain degree of elasticity, the support member 20 or 3 that supports the mover 2 or the stator 1, respectively, can be made smaller while maintaining the same performance as the conventional one.

In the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Example An embodiment of the present invention will be described with reference to FIGS. 1 to 3a.

FIG. 1 is a perspective view of the main parts of an ultrasonic motor according to an embodiment of the present invention, and FIG. 2 is a sectional view of the ultrasonic motor.

The stator (stator) 1 is composed of a ring-shaped elastic body 1a and a ring-shaped piezoelectric body 1b bonded to the ring-shaped elastic body 1a. A comb-shaped groove is formed on the contact surface lc side. The stator 1 has a flange portion 1d protruding radially from the vicinity of the neutral axis located on the circumferential surface of the elastic body 1a, and the flange portion 1d extends from the upper surface of the supporter 3a constituting the ring-shaped stator support member 3. It is glued and supported.

The vicinity of the neutral axis is a region with the least vibration, and the stator 1 is supported efficiently. The outer edge of the stator support member 3 is held between a presser ring 4 and a fixed cylinder 5.

As a result, the stator 1 is installed in the fixed cylinder 5.

Note that the holding ring 4 is screwed onto the fixed cylinder 5.

As clearly shown in FIG. 3a, the stator support member 3 is composed of an annular main body 3b and a support member 3a having 1 elasticity. A plurality of supports 3a are arranged at equal intervals on the inner periphery of the support member main body 3b, and protrude obliquely at a certain inclination with respect to the movement direction (tangential direction) of the rotor 2. The length of the supporter 3a along the inclination is the same as that of the conventional supporter protruding in the radial direction (direction perpendicular to the rotor motion direction), and has the same degree of elasticity. Therefore, the outer diameter of the support member 3 is smaller than that of the support member 13 of the conventional example. The number of supports 3a is an integral multiple of the wave number of the traveling wave generated in the stator.

On the other hand, the rotor 2 is composed of a ring-shaped rotor base material 2a and a slider material 2b bonded to the rotor base material 2a. The rotor 2 is excited by the vibration of the stator 1,
A traveling wave having the same wave number as the stator 1 is generated. Therefore, in this embodiment, the rotor 2 is
support. That is, supports 20a are integrally provided on the rotor base material 2a and project from the vicinity of the neutral axis at a certain inclination with respect to the rotor movement direction and at predetermined intervals in the circumferential direction, and the tips of the supports 20a receive pressurizing force. The support member main body 20b is integrally molded. This supporter 20a and the support member main body 2
0b constitutes the rotor support member 20. Note that the number of supports 20a is provided as many as an integral multiple of the wave number of the traveling wave generated in the rotor base material 2a. This supporter 20a is
As described above, since the rotor 2 is protruded from the vicinity of the neutral axis of the rotor base material 2a, the rotor 2 is supported at the part with the least vibration, resulting in good efficiency.

The rotor 2 is installed inside the fixed cylinder 5, and the elastic body 1a of the stator 1 installed in the fixed cylinder 5 as described above.
is brought into pressure contact with. That is, the pressing force by the pressing member 6 is transmitted to the rotor 2 via the ball bearing 8, so that the rotor 2 comes into pressure contact with the elastic body 1a. This ball bearing 8 is provided for the purpose of reducing rotational resistance between the rotor 2 and the pressure member 6, and is composed of a retaining ring 8a and a rigid ball 8b, and the rigid ball 8b is accommodated in a groove 20c on the surface of the rotor support member 20. ing.

In the ultrasonic motor having the above configuration, when an AC voltage of a predetermined frequency is applied to the piezoelectric body 1b from a drive control circuit (not shown), the piezoelectric body 1b is excited, and this causes a traveling wave to be generated on the drive surface 1c of the elastic body 1a. Occur. The rotor 2 has a pressure member 6
Since it is in pressure contact with the drive surface 1c, it is frictionally driven by the traveling waves generated in the elastic body 1a and rotates.

In the embodiment configured in this way, while exhibiting the same support performance as the conventional one, the outer diameters of the stator supporting member 3 and the rotor supporting member 2o are larger than the conventional one by the amount that the respective supports 3a and 20a are tilted. Can be made smaller. That is, in this embodiment, the ultrasonic motor can be downsized while minimizing loss due to support and increasing drive efficiency.

Another embodiment of the stator support member 3 is shown in FIG. 3b. In FIG. 3a, all the supports 3a of the support member 3 are projected at the same inclination with respect to the rotor movement direction, but in FIG. 3B, the supports 30al and 30a2 of the support member 30 are Efficiency equivalent to that of the support member 3 is obtained by protruding with two types of inclinations.

Further, in the above description, the shape of the supporter is a linear shape, but it may be a curved shape having the same degree of elasticity.

Furthermore, although the supporter is formed into a planar shape that spreads within the same plane, it may also have a shape with steps in the longitudinal direction of the axis. The above modifications also apply to the supporter 20a of the rotor 2.

Further, in the above embodiment, the stator support member 3 is provided separately from the stator 1, and the rotor support member 20 is provided integrally with the rotor 2.
The rotor support member 20 may be integrated with the rotor 2, or the rotor support member 20 may be configured separately from the rotor 2.

Further, in this embodiment, an annular type ultrasonic motor has been described, but the present invention can also be applied to a disc type ultrasonic motor and a linear type ultrasonic motor.

G1 Effects of the Invention As described above, according to the present invention, by providing the supports of the stator or mover support member obliquely with respect to the direction of movement of the mover, it is possible to The outer diameter of the support member can be reduced while having the same support performance as a conventional support member that protrudes in the radial direction), and a small-sized ultrasonic motor can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of an ultrasonic motor according to the present invention;
FIG. 2 is a sectional view of the ultrasonic motor, FIG. 3a is a plan view of the stator support member of the ultrasonic motor shown in FIG. 1, and FIG. 3b is a plan view showing a second embodiment of the stator support member. 4 is a perspective view of the main parts of a conventional ultrasonic motor, and FIG. 5 is a plan view of a conventional stator support member. 1: Stator 1a: Elastic body 1b: Piezoelectric body 2: Rotor 2a: Rotor base material 2b Varnish slider material 3.30: Stator support member 3a, 3Qa: Support elements 3b, 30b: Stator support member main body 20: Rotor support member 20a: Support element 20b: Rotor support member body Patent applicant: Nikon Co., Ltd. Patent attorney Fuyu Ki Nagai Figure 2 Whistle Figure 4, Figure 3b

Claims (1)

[Scope of Claims] A stator that generates progressive vibration waves in an elastic body by excitation of a piezoelectric body and is fixed to the stationary side by a first support member; The second wave driven
In the ultrasonic motor, the first and/or second support members are protruded diagonally at predetermined intervals with respect to the movement direction of the slider. An ultrasonic motor characterized in that it has a plurality of supports, and the movable element or the stator is held by the supports.