JPS62147974A - Supersonic motor - Google Patents

Abstract

PURPOSE:To limit the loss caused by a support to minimum by performing the support of a stator or a rotor with the supporting pieces of integer multiples of wave number of progressive waves. CONSTITUTION:A stator is composed of an elastic body 1 and a piezoelectric body 2 combined, while a rotor is composed of a rotor parent material 3 and a slider 4. A supporting member 5 for a stator is annular-ringed and has an elastic L-shaped supporting piece 5a. Likewise, a supporting member 6 for rotor is annular-ringed and has an elastic L-shaped supporting piece 6a. The supporting pieces 5a and 6a are provided in integer multiples of the wave number of the progressive waves respectively.

Description

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

(Foreground of the Invention) Conventionally, this type of device consists of a stator made of a piezoelectric body and an elastic body, and a rotor that is brought into pressure contact with the stator, and a driving circuit generates a traveling wave in the stator.
It was configured to drive a rotor that was in pressure contact. Since this stator is excited while indirectly receiving pressure from the rotor, a buffer support member (for example, felt, etc.) having a buffering effect is used between this stator and a fixed part that fixedly supports the stator. Ta.

However, since this buffer support member structurally contacts almost the entire surface of the piezoelectric element, it tends to damp vibrations of the stator, which hinders improvement in drive efficiency.

Furthermore, a similar problem arises when supporting a rotor that is driven by the excitation of a stake.

(Objective of the Invention) The object of the present invention is to solve these problems and obtain an ultrasonic motor with high drive efficiency.

(Summary of the Invention) The present invention provides support for the stator or rotor using supports that are an integral multiple of the traveling wave.
The technical key is to minimize support loss and improve the drive efficiency of the ultrasonic motor.

(Embodiment) FIG. 1(A) is an exploded perspective view of an ultrasonic motor according to an embodiment of the present invention, and FIG. 1(B) is a sectional view taken along the line AA of the ultrasonic motor.

In FIGS. 1(A) and (B), an annular elastic body 1
An annular piezoelectric body 2 is integrally bonded to the piezoelectric body 2, and an AC voltage of a predetermined frequency is applied to the piezoelectric body 2 from a drive control circuit (not shown) to excite the piezoelectric body 2. Due to the excitation of the piezoelectric body 2, a traveling wave of a predetermined wave number (nine waves in this embodiment) is generated on the drive surface 1a of the elastic body 1. A stator is constructed by combining the elastic body 1 and the piezoelectric body 2.

The stator support member 5 has an annular shape and has nine elastic L-shaped supports 5a (the same number as the wave number of the traveling wave). As shown in FIG. 1(B), this supporter 5
a are arranged at equal intervals around the circumference of the support member 5, and their tip portions 5b protrude toward the inner circumferential side of the support member 5. The tip portions 5b of the nine supports 5a are in contact with and fit into the outer circumferential lower part IC of the elastic body 1 to which the piezoelectric body 2 is adhered, and the upper portion 5c of the supports 5a is connected to the elastic body 1. It abuts and engages with the flange portion 1b provided on the outer peripheral portion of the flange portion 1b. In this way, the stator is supported in the radial direction of the elastic body 1 by the tip portion 5b of the supporter 5a, and is supported by the upper portion 5C of the supporter 5a.
is supported in the thrust direction. The stator is attached to the tip 5b of the supporter 5a by adhesion or fitting.
It is fixed to the support member 5. The flange portion 1b of the elastic body 1 is provided near the neutral axis of the stator made up of the elastic body 1 and the piezoelectric body 2, and is the part that vibrates least when the stator vibrates.

The rotor is composed of a rotor base material 3 and a slider 4, and is driven by the stator by bringing the driving surface la of the elastic body 1 of the stator into pressure contact with the slider 4 of the rotor. The rotor is pressed into contact with the stake by a pressure member (not shown) via the support member 6 for the rotor. At this time, the rotor undergoes forced vibration under the excitation of the stator, producing nine traveling waves (same number as the number of traveling waves of the stator), so it is desirable that the rotor be supported in the same way as the stator.

Therefore, similar to the stator support member 5, the rotor support member 6 has an annular shape and has nine elastic L-shaped supports 6a (same number as the number of traveling waves). Exists. As shown in FIG. 1(B), the supports 6a are arranged at equal intervals around the circumference of the support member 6, and their tips 6b protrude toward the inner circumference of the support member 6. These nine supports 6
The tip portion 6b of the support member 6a contacts and fits into the upper outer circumferential portion 3C of the rotor base material 3, and the upper portion 6c of the supporter 6a abuts against the flange portion 3b provided on the outer circumferential portion of the elastic body l. are in contact and engaged. In this way, the rotor is supported in the radial direction of the rotor base material 3 by the tip end 6b of the supporter 6a, and in the thrust direction by the upper part 6c of the supporter 6a. The rotor is fixed to the support member 6 by adhesion or fitting to the tip 6b of the support element 6a.

The flange portion 3b of the rotor base material 3 is provided near the neutral axis of the rotor consisting of the rotor base material 3 and the slider 4, and is the part that vibrates least when the rotor vibrates.

Figure 2 shows the piezoelectric body surface when the stator in Figure 1 is viewed from the piezoelectric body 2 side, and the piezoelectric body 2 is divided into four parts 2a, 2b, 2C, and 2d as shown by solid lines in Figure 2. The electrode is split. The piezoelectric body 2 is further divided into 18 electrodes as shown by solid lines and dotted lines on the adhesive side with the elastic body 1, and as shown in the figure, the electrodes are divided into 18 parts on the back side of 2b and 2d. - Polarized in alternate negative directions.

As a result, when an AC voltage is applied by a drive control circuit (not shown), nine predetermined traveling waves are generated in the elastic body l.

Therefore, we support a stator that generates nine traveling waves,
In order to prevent imbalance between each wave at all times, it is necessary to support it with nine supports or an integral multiple thereof, and to arrange the supports at equal intervals (indicated by arrows in Figure 2). It becomes necessary. This also applies to the rotor. For example, if the supports are arranged at unequal intervals or simply at equal intervals, the places where the supports influence each wave of the traveling wave (nine waves in the example) will be different for each wave. As a result, the shape of the traveling wave becomes non-uniform and greatly distorted, which has an adverse effect on driving.

Note that the present invention is not limited to the embodiments described above and can be modified as appropriate. In the embodiments, the stator and the rotor are supported and fixed by a support member 5.6 having supports 5a and 6a. However, for example, instead of supporting the stator and rotor with separate support members as in the embodiment, supports in number equal to an integral multiple of the wave number of the traveling wave are arranged at equal intervals near the neutral axis of the stator or rotor. In this way, the stator or rotor may be integrally formed near the neutral axis of the stator or rotor. Since it is supported and fixed to the base via the support, the same effects as in the embodiment can be obtained. Therefore, it is possible to adopt a configuration in which a support member having a support element is provided separately from the stator and rotor as in the embodiment, or a configuration in which the support element is integrally formed with a stake or a rotor, so that the use of the ultrasonic motor can be determined as appropriate. The structure of the support can also be selected by

Furthermore, in this embodiment, the rotor has been described as an annular moving body, but the rotor in the present invention is a general term for a moving body driven by a stator, and is limited to an annular shape. Rather, for example, in a linear type ultrasonic motor, the shape is suitable for translational movement.

Furthermore, in this embodiment, the supporting members for the stator and rotor are configured to support the outer circumferential surfaces of the stator and rotor, but are not limited to this. For example, the supporting member for the stator and rotor is annular. If so, the inner circumferential surface side thereof may be supported in the same manner as in the embodiment.

(Effects of the Invention) As described above, according to the present invention, the stator or rotor is supported by supports whose number is an integral multiple of the wave number of the traveling wave, thereby making it possible to minimize the loss due to the support. , it is possible to obtain an ultrasonic motor with high drive efficiency.

Furthermore, by changing the supporting member from felt or the like as in this embodiment, a secondary effect can be expected that the positional support precision of the stator and rotor can be improved.

[Brief explanation of drawings]

FIG. 1(A) is an exploded perspective view of an embodiment of the ultrasonic motor according to the present invention, FIG. 1(B) is a sectional view of the ultrasonic motor taken along arrow AA, and FIG. FIG. 4 is a plan view of the piezoelectric body when the stake of FIG. 4(A) is viewed from below. (Explanation of symbols of main parts) 1... Elastic body, 2... Piezoelectric body,

Claims (5)

[Claims] (1) It has a stator that generates a traveling wave of a predetermined wave number on the surface of an elastic body by excitation of a piezoelectric body, and a rotor that is driven by the traveling wave, and the stator or the rotor is driven by an integer of the wave number of the traveling wave. An ultrasonic motor characterized in that it is supported by multiple supports, and the supports are arranged at equal intervals. (2) The ultrasonic motor according to claim (1), wherein the support member is formed on a support member provided separately from the stator or the rotor. (3) The ultrasonic motor according to claim (1), wherein the supporter is provided integrally with the stator or the rotor. (4) The ultrasonic motor according to claim (1), wherein the supporter has elasticity. (5) Claim (1) characterized in that the stator and the rotor have an annular shape, and the supports are arranged at equal intervals on the circumference of the stator and the rotor. Ultrasonic motor as described.