JP2620609B2 - Ultrasonic drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic drive device having a long life by dispersing wear of a stator with a magnetic material and a ball.

[Prior Art] In an ultrasonic motor proposed at present, two sets of electrodes are adhered to one side of a ring-shaped piezoelectric ceramic so that standing waves excited by each of the sets of electrodes are shifted in position by π / 2. Are arranged, and the portions of the ring-shaped voltage ceramic corresponding to these electrodes are alternately and reversely polarized. Further, the AC electric field applied to these two sets of electrodes has a π / 2 phase difference in time. One that connects two sets of oscillators has been proposed.

In the ultrasonic motor thus configured, two standing waves having a π / 2 phase shift are applied to the surface around the ring-shaped voltage ceramic by applying an AC electric field to each electrode group from two sets of transmitters. Then, a traveling wave in which the two standing waves are combined is generated. Therefore, when the ring-shaped moving body is placed on the vibrating body adhered on the ring-shaped piezoelectric ceramic and the contact is strengthened, the moving body is moved by the traveling wave.

Since this ultrasonic motor presses the rotating body against the vibrating body,
There is a drawback that the rotating body or the vibrating body is worn and the life is short.

To solve this drawback, an ultrasonic motor using a ball bearing has been proposed (Japanese Patent Application Laid-Open No. 61-295882).
Reference). In this ultrasonic motor, as shown in FIG. 9, an elastic body 2 such as rubber or sponge is mounted on the inner surface of a recess 1a of a ring-shaped rotating body 1, and a large number of elastic plates 2 are mounted on a retainer 3 of a bearing. The ball 4 is brought into contact with the ball 4 and the ball 4 is brought into contact with the vibrating body 6 of the stator 5. Therefore, the frictional force between the elastic plate 2 and the ball 4 is configured to be stronger than the frictional force between the ball 4 and the vibrating body 6. In addition,
A piezoelectric vibrator 7 is adhered to the vibrator 6.

The ultrasonic motor configured as described above is used for the piezoelectric vibrator 7.
Is driven to generate a traveling wave in the vibrating body 6, the rotating body 1 rotates while the ball 4 slightly rotates.
Is reduced, and the life of the motor is extended.

[Problems to be Solved by the Invention] However, in this conventional ultrasonic motor, the ball 4 slides on the vibrating body 6 of the stator 5 without rotating so much that the vibrating body 6 is worn and the life is not prolonged much. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic drive device in which a ball is attracted and rotated by a magnet to significantly extend the life.

[Means for Solving the Problems] In order to achieve the above object, in the ultrasonic driving apparatus of the present invention, a magnetic body is attached to an end face of a stator that generates an elliptical vibration or a traveling wave, and the magnetic body is rotated. The magnet to which the shaft is fixed is attracted and the ball is attracted around the magnetic body, thereby rotating the magnet through the ball.

Further, an asymmetric bolt shrinkage Langevin type vibrator may be used for the stator.

Further, the stator may use a ring-shaped piezoelectric vibrator.

Further, a lubricant such as grease may be attached around the ball.

[Operation] In the sound wave drive device configured as described above, when the magnet having the rotating shaft fixed to the magnetic body of the stator is attracted and the magnet rotates, and the ball is attracted and magnetized by the magnet, Since the ball is attracted by the magnetic material of the stator and the ball rotates slowly, wear can be reduced without concentrating on the magnetic material, and also on a part of the ball, thereby reducing the wear. By using a lubricant such as grease around the periphery, wear can be further reduced and durability can be increased. The stator may be an asymmetrical bolted Langevin type vibrator or a ring-shaped piezoelectric vibrator.

[Example] An example will be described with reference to the drawings. In FIG.
The nut 10 is screw-fitted to the screw at the tip 9 '. The tip 9 'of the bolt 9 protrudes from the nut 10, and the bolt 9
Is inserted into a hole of a ring-shaped magnet 12 to which a rotating shaft 11 is fixed. As shown in FIG. 2, a large number of balls 13 are attracted around the magnet 12, and the balls 13 are magnetized so as to be attracted to a nut 10 which is a magnetic material of the stator 8.

In the ultrasonic driving apparatus of the present embodiment configured as described above, the ball 13 is magnetized by the magnet 12 and
Nut by stator 8 by being sucked by 10
The magnet 12 rotates normally through the ball 13 by the elliptical vibration or the traveling wave generated in the
Since it rotates very slowly, the ball 13 and magnet
12 can reduce abrasion without abrasion being concentrated on one point. By applying or filling a lubricant such as grease or oil around the ball 13,
13, wear of the magnet 12 and the nut 10 can be further reduced.

Also, as shown in FIG. 3, even if the magnetic body 14 is fixed to the stator 8 with bolts 9 like an iron plate instead of the nut 10,
The magnet 12 can be driven to rotate similarly to the embodiment of FIG.

As a stator 8 used in such an ultrasonic drive device, a stator proposed by the present applicant (Japanese Patent Application No. 62-48517).
4), a short metal block 15 as shown in FIG.
And one or more (two in this example) piezoelectric vibrators 17, 18 and electrodes 19, 20 are sandwiched between the metal block 16 and the long metal block 16. The bolts 21 are integrally formed by fitting the screws 21a and 21b at both ends. When an AC voltage is applied to the electrodes 19 and 20, the piezoelectric vibrators 17 and 18 vibrate in the thickness direction, thereby torsion occurs due to the inclination of the screws 21a and 21b of the bolt 21. Elliptical vibration or traveling waves in one direction are generated on the side surfaces and end surfaces of the blocks 15 and 16.

Further, the stator 8 used in the ultrasonic drive device described above.
As the stator proposed by the present applicant (Japanese Patent Application No. 62-1873)
In FIG. 5, the divided electrodes 23a and 23b and the electrodes 24a and 24b are continued on both end surfaces of the columnar piezoelectric vibrator 22, as shown in FIG. And the electrodes 23a and 23b and the electrodes
The gaps 25 and 26 between 24a and 24b are shifted from each other (90 ° in this embodiment, but can be shifted arbitrarily).

In the stator 8 configured as described above, for example, the electrodes 23a
When an AC voltage is applied to the electrode 24a and the electrode 24a, a rotational vibration that rotates in one direction is generated as shown by an arrow A in FIG.
When an AC voltage is applied to the electrode 23b and the electrode 24a, an arrow B in FIG.
Rotational vibration that rotates in the opposite direction is generated as shown by.

This is because, for example, when an AC voltage is applied to the electrode 23a and the electrode 24a, the electrode 23a and the electrode 24a are shifted from each other by 90 °.
The voltage acts obliquely in the thickness direction as shown by the arrow C in the figure, so that the vibration in the thickness direction causes a torsional rotation, and the end face and the side face of the piezoelectric vibrator 22 generate a rotary vibration as shown by the arrow A. It seems to be. Similarly, when a voltage is applied to the electrode 23b and the electrode 24b, a rotational vibration is also generated in the direction of arrow A. Here, when a voltage is applied to the electrode 23b and the electrode 24a by reversing the direction of the applied voltage, the voltage acts in the reverse direction as shown by the arrow D in FIG. 5, so that the vibration in the thickness direction causes a torsional rotation. Then, a rotational vibration as shown by an arrow B occurs on the end face and the side face of the piezoelectric vibrator 22. Also, the electrode 23a and the electrode 24b
Similarly, when a voltage is applied, rotational vibration is generated in the direction of arrow B.

Furthermore, a stator proposed by the present applicant (Japanese Patent Application No. 62-18 / 1987)
In FIG. 7, the outer electrode and the inner electrode of the ring-shaped piezoelectric vibrator 27 are divided into two to form divided electrodes 28a, 28b, 29a, and 29b, respectively. The positions of the gaps 30a, 30b between the electrodes 28a, 28b and the gaps 31a, 31b between the divided electrodes 29a, 29b are shifted from each other. When an AC voltage is applied to the divided electrodes 28a and 29a, an elliptical vibration or traveling wave is generated in the direction of arrow A. When an AC voltage is applied to the divided electrodes 28a and 29b, the elliptical vibration or traveling wave is generated in the direction of arrow B. Occurs. When an AC voltage is applied to the divided electrodes 28b and 29a, an elliptical vibration or a traveling wave in the direction of arrow B is generated. When an AC voltage is applied to the divided electrodes 28b and 29b, the elliptical vibration or the traveling wave in the direction of the arrow A is generated. Occurs.

Referring to FIG. 8, another embodiment of the present invention using the stator of FIG. 7 is shown. Here, the stator 8
Is supported on a case 32 by a support 33, an iron plate magnetic body 34 is supported on an end face of the stator 8 by bolts 35, and a tip 35 'of the bolt 35 is inserted into a hole 12' of the magnet 12 to which the rotating shaft 11 is fixed. Have been. A large number of balls 13 are attracted around the magnet 12.

In the ultrasonic driving apparatus having such a configuration, the first
As in the embodiment shown in FIGS. 3 and 3, the elliptical vibration or traveling wave generated in the magnetic body 34 by the stator 8 causes the ball 13 to move.
The ball 13 and the magnet 12 rotate normally, and the ball 13 and the magnet 12 rotate very slowly, so that the wear of the ball 13 and the magnet 12 can be reduced without being concentrated on one point. Similarly, by applying or filling a lubricant such as grease or oil around the ball 13, wear of the ball 13, the magnet 12, and the magnetic body 31 can be further reduced.

[Effects of the Invention] Since the present invention is configured as described above,
Since the magnet rotates through the ball attracted to the magnet with the rotating shaft fixed thereto, and the ball rotates very slowly, the wear of the ball, magnet and magnetic material can be significantly reduced, and the life of the motor can be reduced. It has the advantage of being significantly extended.

[Brief description of the drawings]

1 is a side view of an ultrasonic driving device according to an embodiment of the present invention, FIG. 2 is a plan view of the ultrasonic driving device of FIG. 1, and FIG. 3 is an ultrasonic driving device of another embodiment of the present invention. FIG. 4 is a side sectional view of a stator of an ultrasonic driving apparatus proposed by the present applicant used in the present invention, and FIG. 5 is a side view of an ultrasonic driving apparatus proposed by the present applicant used in the present invention. Perspective view of stator, sixth
The figure shows the direction of the elliptical vibration or traveling wave generated in the stator of FIG. 5, FIG. 7 is a perspective view of the stator of the ultrasonic driving device proposed by the applicant used in the present invention, and FIG. FIG. 9 is a side view of an ultrasonic driving apparatus according to still another embodiment of the present invention, and FIG. 9 is a side sectional view of a conventional ultrasonic motor. 8 ... stator, 9 ... nut, 10 ... bolt, 11 ...
Rotating shaft, 12 ... magnet, 13 ... ball, 14 ... magnetic material.

Claims (4)

(57) [Claims] A magnetic body is attached to an end face of a stator that generates an elliptical vibration or a traveling wave, and a magnet having a rotating shaft fixed to the magnetic body is attracted, and a ball is attracted around the magnetic body. An ultrasonic driving device characterized by rotating a magnet through a ball. 2. The ultrasonic driving apparatus according to claim 1, wherein said stator is an asymmetrical bolted Langevin type vibrator. 3. The ultrasonic drive device according to claim 1, wherein said stator is a ring-shaped piezoelectric vibrator. 4. The ultrasonic driving device according to claim 1, wherein a lubricant such as grease is adhered around the ball.