JP3049400B2 - Cylindrical rotation reduction gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotation reduction device for a cylindrical body in which an adjustment cylinder provided on an outer periphery of a fixed cylindrical portion can be rotationally adjusted at a low speed by a ring type ultrasonic motor. About.

2. Description of the Related Art It is known that, if an aperture operation of a camera is performed by an ultrasonic motor, the size of the apparatus is small, the operability is good, and the generated sound is small.

However, when a conventional camera aperture mechanism using an ultrasonic motor is applied to a camera such as a television camera which needs to change the aperture slowly, it is necessary to further reduce the speed, which is difficult to use.

[Problems to be Solved by the Invention] Although there is a conventional camera aperture mechanism using an ultrasonic motor, the apparatus has not been sufficiently miniaturized in order to slowly change the rotation of the cylindrical body. There is a demand for a dynamic reduction gear having a small size and good operability.

Accordingly, an object of the present invention is to reduce the output speed of a ring-type ultrasonic motor and reduce the size thereof, thereby improving the operability of rotating the cylindrical body.

[Means for Solving the Problems] The present invention is a cylindrical body rotation reduction device which achieves the above-mentioned object in an adjustment cylinder rotatably provided on the outer periphery of a fixed cylindrical body. That is, the casing of the ring-type ultrasonic motor is fixed to the outer periphery of the fixed cylindrical portion, and the rotor is pressed against the stator through a ring-shaped guide member and a plurality of bearing balls by a spring provided in the casing, and the bearing ball is fixed. Was rotatably fitted to a plurality of through holes provided in the flange portion of the adjustment cylinder.

[Operation] In the above-described rotation reduction device for the rotating body, when the rotor is rotated by driving the ring-type ultrasonic motor, the bearing ball in contact therewith is rotated. In this case, since the ring type guide member of the bearing ball is in a fixed state,
The bearing balls revolve and revolve around the outer periphery of the fixed cylindrical portion at half the speed of the rotor. By this revolution, the adjustment cylinder on which the bearing ball is fitted also rotates integrally.

[Example] An example of the present invention will be described with reference to the drawings.

For example, in a small television camera, an adjusting cylinder 2 for adjusting the aperture of a lens is provided around the distal end of a fixed cylindrical portion 1 to be fixed.
Is rotatably provided, and the aperture can be adjusted by rotating the adjustment cylinder 2 by the ring-type ultrasonic motor 3.

The cylindrical casing 4 of the ring type ultrasonic motor 3 is attached to the fixed cylindrical portion 1. A ring-shaped projection 4a is provided on the inner periphery of one end in the axial direction of the cylindrical casing 4, and a ring-shaped stator 5 is supported on the inner periphery. A piezoelectric element 6 is bonded to the outer surface of the stator 5. As is well known, a driving signal is applied to the piezoelectric element 6 to cause the piezoelectric element 6 to vibrate, thereby generating a traveling wave in the stator 5. A cavity 7 is provided in the casing 4 at a position facing the piezoelectric element 6, and the cavity 7 is filled with cotton 8 so that the vibration of the stator 6 is not directly transmitted to the casing 4. The cavity 7 is communicated to the outside through a through hole in the casing, and a conducting wire 9 for applying a drive signal passes through the through hole and the cotton 8 in the cavity 7,
The conductor 9 is connected to the piezoelectric element 6 by soldering or the like.

On the opposite side of the stator 5 from the piezoelectric element side, a ring-shaped rotor 10 is overlaid. A slider member 11 is adhered to the stator side of the rotor 10 so that the rotor 10 is rotated by the traveling wave of the stator 5. A ring groove 12 for adjusting the natural frequency of the rotor 10 is provided on the outer periphery of the rotor 10 so that the natural frequency ratio with the stator 5 can be adjusted.

On the opposite side of the rotor 10 from the stator side, a ring-shaped guide 14 is mounted via a cushioning material 13 such as rubber material or cotton, which rotates integrally with the rotor 10. Another ring-shaped guide 15 is provided opposite to the ring-shaped guide 14 at an interval, and the ring-shaped guide 15 is provided.
Is mounted in the casing 4 so as to be slidable in the axial direction. The ring guide 15 has a spline structure so that it cannot rotate in the circumferential direction with respect to the casing 4.

A plurality of bearing balls 16 are interposed between the ring-shaped guide 14 and the ring-shaped guide 15, and a part of the outer periphery of the bearing balls 16 is provided on the opposing surfaces of the two ring-shaped guides 14 and 15, respectively. It is designed to enter the concave groove. A spring 17 is provided on the outer side of the ring-shaped guide 15 in the axial direction. The spring 17 is fixed to the casing 4 and has two ring-shaped guides 14 and 15 and a bearing ball 16.
The rotor 10 is brought into pressure contact with the stator 5 through the contact. That is, when the rotor 10 is pressed against the stator 5 in this way, the traveling wave of the stator 5 is effectively
It works on 10.

The base end of the adjusting cylinder 2 extends to the inner periphery of the spring 17 and the ring-shaped guide 15, and a flange 2a is provided at the base end between the two ring-shaped guides 14 and 15. A plurality of through holes 18 are provided in the flange 2a,
One of the bearing balls 16 is rotatably fitted into each through hole 18. The rotation of the rotor 10 causes the bearing balls 16 to revolve, and revolves around the outer periphery of the fixed cylindrical portion 1. Due to this revolution, the aperture adjustment cylinder 2 is rotated, and its speed is equal to the rotation speed of the rotor 10.
It turns at 1/2.

[Effects of the Invention] According to the rotation reduction device of the present invention, the adjustment cylinder is rotated at half the rotation speed by the rotor of the ultrasonic motor via the bearing ball, and the adjustment cylinder is slowly rotated with good operability. You. In addition, since a void is provided in the soldering portion of the lead wire to the piezoelectric element of the ultrasonic motor and cotton or the like is interposed, the vibration state of the stator is kept good and the connection portion of the lead wire does not break. . Furthermore, by providing a ring groove for natural frequency adjustment on the outer circumference to the rotor,
The natural frequency ratio with the stator can be easily adjusted, and the motor characteristics can be improved.

[Brief description of the drawings]

The drawings are judgment drawings showing the rotation reducing device for the rotating body of the present invention. 1; fixed cylindrical part, 2; adjusting cylinder 3; ring type ultrasonic motor 5; stator, 10; rotor 16; bearing ball, 17; spring

Claims (2)

(57) [Claims] 1. An adjusting cylinder having a through hole at the center, a ring-type ultrasonic motor having at the center a through hole having substantially the same size as the through hole of the adjusting cylinder, a through hole and an ultra A fixed cylindrical portion inserted into a through hole of the ultrasonic motor; the adjusting cylinder is rotatably provided at one end of the fixed cylindrical portion; and the ultrasonic motor is attached to the other end of the adjusting cylinder. Is provided with a flange so as to be located at the end thereof and between the following two ring-shaped guides of the ultrasonic motor to restrain movement in the axial direction. The ultrasonic motor comprises: a ring-shaped piezoelectric element, a ring-shaped stator, a ring-shaped slider material, a ring-shaped rotor, a ring-shaped buffer, and two ring-shaped guides. The adjustment cylinder is inserted into a plurality of through holes of the flange. A plurality of bearing balls, a ring-shaped spring, and a cylindrical casing are provided. The cylindrical casing is provided with two ring-shaped protrusions at a predetermined interval on an inner peripheral surface thereof. The ring-shaped stator is attached to the ring-shaped projection, and the slider material, the rotor, the cushioning material, and the one guide are provided between the other ring-shaped projection and the ring-shaped stator. A state in which the bearing cylinder, the other guide, and the spring are sequentially inserted, and the adjusting cylinder is axially constrained by rotating and revolving the plurality of bearing balls by rotating the rotor. A rotation reduction device for a cylindrical body, characterized in that the adjustment cylinder is rotated. 2. The rotation of a cylindrical body according to claim 1, wherein the ring-shaped rotor is provided with a ring groove for adjusting a natural frequency in a direction perpendicular to an axial direction on an outer peripheral surface thereof. Reduction gear.