JP2601659B2 - Ultrasonic drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic driving apparatus using a ring-shaped piezoelectric vibrator using divided electrodes.

2. Description of the Related Art Conventionally, there has been proposed an ultrasonic motor in which rotational vibration is generated on a side surface of a thin disk of a piezoelectric vibrator, and a rotary body is pressed against a side surface of the piezoelectric vibrator to rotate the rotary body. .

In this conventional ultrasonic motor, in order to generate rotational vibration on the side of the thin disk, the disk of the piezoelectric vibrator is divided into a plurality of parts by a line passing through the center, and a voltage is applied to each part of the disk. There is a difference in expansion and contraction in each part of the disk, resulting in a distorted shape that is deviated from the center.However, if you control the way of applying voltage to each part so that this distortion rotates, it will contact the side of the piezoelectric vibrator Rotating body rotates.

Problems to be Solved by the Invention However, this conventional ultrasonic motor has a complicated structure and separates the disk of the piezoelectric vibrator and controls the voltage applied to these divided portions. However, there is a problem that a circuit to be used becomes complicated.

Means for Solving the Problems In order to solve the above problems, the present invention provides a ring-shaped piezoelectric vibrator polarized in the thickness direction, and a dividing line for each gap at both end faces of the piezoelectric vibrator. And an AC power supply connected to one of the two equally-divided electrodes on both end surfaces thereof, and an electrode in which the dividing lines are shifted at a predetermined angle from each other. And a rotating body combined with the end face or side face of the ring-shaped piezoelectric vibrator.

According to the present invention, the electrodes are substantially equally divided into two on both surfaces of the ring-shaped piezoelectric vibrator by dividing lines of the respective gaps, and one of the divided electrodes on one surface of the piezoelectric vibrator and the other are divided. By applying an AC voltage between one electrode on one surface of the piezoelectric vibrator or between one split electrode on one surface of the piezoelectric vibrator and the other electrode on the other surface, the side surface of the ring-shaped piezoelectric vibrator Alternatively, a forward / reverse traveling wave can be generated on the end face, so that the rotating body can be normally / reversely rotated by combining the rotating body with the end face or side face of the piezoelectric vibrator.

Embodiment FIG. 1 is a structural view of a stator of an ultrasonic driving apparatus according to an embodiment of the present invention.
a, 2b, 3a and 3b are provided respectively. Gap 2 between these electrodes
c, 2d, 3c, 3d are parallel on the upper and lower surfaces as shown in FIG.
Alternatively, as shown in FIG.

In the thus configured stator 4 of this embodiment,
For example, when the divided electrodes 2a and 3a are connected, and the divided electrodes 2b and 3b are connected and an AC voltage is applied between the divided electrodes 2a and 3b, rotational vibration occurs in one direction on the side surface and the end surface of the piezoelectric vibrator 1 at the resonance frequency. When an AC voltage having a frequency slightly deviated from that frequency is applied, rotational vibrations in opposite directions are generated on the side surface and the end surface of the piezoelectric vibrator 1.

In the case of a stator whose electrodes are shifted by 90 ° as shown in FIG. 2, similarly, the divided electrodes 2a and 3a are connected,
When an AC voltage is applied between 2b and 3b and between them, a rotational vibration is generated in one direction on the side surface and the end surface of the piezoelectric vibrator 1 at the resonance frequency, and the divided electrodes 2a and 3b are connected. When the divided electrodes 2b and 3a are connected and an AC voltage is applied therebetween, rotational vibrations in opposite directions are generated on the side and end surfaces of the piezoelectric vibrator 1 at the resonance frequency.

This is because when an AC voltage is applied, when the half of the piezoelectric vibrator 1 is unfolded as shown in FIG. 3 (b) and viewed from the side, vibration in the thickness direction is generated as shown by arrow A. At the same time, vibration as shown by arrow B is generated in the side direction, and furthermore, radial vibration is generated as shown by arrow C in FIG. 3 (a). It is considered that the vibrations combine with each other to generate rotational vibration.

As shown in FIG. 4, when the rotating body 5 is pressed against the stator 4 according to the present embodiment in which the rotational vibration is generated, the rotating body 5 has a predetermined frequency or the voltage of the electrodes 2a, 2b, 3a, 3b. Is reversed by the rotational vibration generated according to the direction of application.

FIG. 5 is a side sectional view of a specific example of the ultrasonic drive device of the present invention. A bearing 7 is provided on a case 6, and a rotating shaft 8 of the rotating body 5 is rotatably supported on the bearing 7. . Further, a thrust bearing 9 is mounted on the rotating body 5 so that the rotating body 5 can rotate with respect to pressing in the axial direction. Further, in order to protect the electrodes of the stator 4, a wear-resistant member is used.
10 is interposed between the rotating body 5 and the stator 4, and a bottom member 12 is fixed to the bottom of the case 6 via a spring washer 11.

In the ultrasonic driving device of the present invention configured as described above,
When the AC voltage is applied, the rotating body 5 rotates forward and backward, so that the rotating body 5 can be used as a small motor.

FIG. 6 is a side sectional view of another embodiment of the ultrasonic driving apparatus of the present invention. A bearing 7 is provided on a case 6, and a rotating shaft 8 of a rotating body 5 is rotatably supported by the bearing 7. I have. A plurality of balls 13 are rotatably mounted on the rotating body 5, and the balls 13 are sandwiched between a support plate 14 provided on the inner surface of the case 6 and a contact plate 15 on the upper surface of the stator 4. The stator 4 is pressed against the contact plate 15 by fixing the bottom member 12 to the bottom of the case 6 via a spring washer 11.

In the ultrasonic driving apparatus of the present invention having the above-described structure, the rotating body 5 is similarly applied by applying an AC voltage.
Can be used as a small motor.

Note that the above ultrasonic driving device is one example, and it goes without saying that other configurations can be adopted. Also, the displacement of the gap between the divided electrodes of the piezoelectric vibrator has been described with respect to 0 ° and 90 °, but may be 45 ° or may be arbitrarily shifted from 0 °, and the displacement may be set as appropriate. it can.

Advantages of the Invention As is clear from the above description, the present invention divides the electrodes on both sides of the piezoelectric vibrator into two parts, and on each side, the AC voltage is applied between one or two of the divided electrodes. Is applied, a forward or reverse traveling wave can be generated on the side face or the end face of the ring-shaped piezoelectric vibrator, so that a rotating body is combined with the end face or the side face of the piezoelectric vibrator. Can be used for a small motor or other driving device.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stator of an ultrasonic driving apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of a stator of an ultrasonic driving apparatus according to another embodiment of the present invention, and FIGS. b) is a diagram for explaining the operation principle of the present invention, FIG. 4 is a side view of the ultrasonic drive device according to the embodiment of the present invention, and FIG. 5 is a side sectional view of a specific example of the ultrasonic drive device of the present invention. FIG. 6 is a side sectional view of another embodiment of the ultrasonic driving apparatus according to the present invention. 1 ... piezoelectric vibrator, 2a, 2b, 3a, 3b ... split electrode, 2
c, 2d, 3c, 3d ... gap between electrodes, 4 ... stator, 5 ...
…Rotating body.

Claims (4)

(57) [Claims] 1. A ring-shaped piezoelectric vibrator polarized in the thickness direction, and both ends of the piezoelectric vibrator are divided into two substantially equal parts by dividing lines of respective gaps, and the dividing lines are fixed to each other. And an AC power supply connected to one of the two equally divided electrodes on both end faces, and a rotating body combined with the end face or side face of the ring-shaped piezoelectric vibrator. An ultrasonic drive device comprising: 2. A rotary vibration generated on an end face or a side face of the ring-shaped piezoelectric vibrator by slightly changing a predetermined frequency of an AC voltage from the AC power supply applied to the two divided electrodes. 2. The ultrasonic drive device according to claim 1, wherein the ultrasonic drive device is rotated forward and reverse. 3. The ultrasonic driving apparatus according to claim 1, wherein the gap between said electrodes is shifted by 45 °. 4. The ultrasonic driving device according to claim 1, wherein the gap between said electrodes is 90 °.