JPH04117184A - Rotation decelerator for cylinder - Google Patents

Abstract

PURPOSE:To reduce the output speed of a ring-shaped ultrasonic wave motor to a low speed by bringing a rotor into pressure contact with a stator side through a ring-shaped guide member and a plurality of bearing balls, and rotatably engaging the balls with a plurality of vent holes formed at the flange of a regulating cylinder. CONSTITUTION:A rotor 10 is brought into pressure contact with a stator 5 to effectively operate a traveling wave of the stator 5 at the rotor 10. The base end of the cylinder 2 is extended to a spring 17, the inner periphery of a ring-shaped guide 15, and a flange 2a to be introduced between the two ring- shaped guides 14 and 15 is provided at the base end. A plurality of vent holes 18 are provided at the flange 2a, and bearing balls 16 are respectively rotatably engaged within the holes 18. The balls 16 are rotated around their own axes by the rotation of the rotor 10, and rotated around the outer periphery of a stationary cylinder 1. The cylinder 2 is rotated by the rotation of the rotor around the cylinder 1, and its speed is 1/2 of the speed of the rotor 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a rotation reduction device for a cylindrical body in which an adjustment cylinder provided on the outer periphery of a fixed cylindrical portion can be rotated at low speed by a ring-type ultrasonic motor. Regarding.

[Prior Art] It is known that if an ultrasonic motor is used to operate the aperture of a camera, the device will be compact, have good operability (and generate less noise).

However, when applying a conventional camera aperture mechanism using an ultrasonic motor to an item such as a television camera that requires a slow change in aperture, the speed must be further reduced, making it difficult to use.

[Problem to be solved by the invention 1 Although some conventional camera aperture mechanisms use ultrasonic motors, the devices have not been miniaturized sufficiently to rotate the cylindrical body slowly; There is a desire for a dynamic reduction gear that is smaller in size and has better operability.

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

[Means for Solving the Problems] The present invention is a rotary speed reduction device for a cylindrical body in which the above object is achieved by an adjustment cylinder rotatably provided on the outer periphery of a fixed cylindrical body. The casing of a ring-type ultrasonic motor is fixed to the outer periphery of a fixed cylindrical part, and a spring provided in the casing presses the rotor against the stator side via a ring-shaped guide member and a plurality of bearing balls. was rotatably fitted into a plurality of through holes provided in the flange portion of the adjustment cylinder.

[Operation] In the above-mentioned rotation reduction device for a rotating body, when the rotor is rotated by the drive of the ring-type ultrasonic motor, the bearing balls in contact with the rotor are rotated.

In this case, since the ring-shaped guide member of the bearing ball is in a fixed state, the bearing ball rotates on its own axis and revolves around the outer periphery of the fixed cylindrical portion at a speed that is 1/2 of the rotational speed of the rotor. Due to this revolution, the adjustment cylinder in which the bearing ball is fitted also rotates together.

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

For example, in a small television camera, an adjustment cylinder 2 is rotatably provided on the outer periphery of the distal end of a fixed identification cylinder part 1 to adjust the aperture of the lens, and a ring-type ultrasonic motor 3 rotates the adjustment cylinder 2. This allows you to adjust the aperture.

A cylindrical casing 4 of the ring-type ultrasonic motor 3 is attached to a fixed cylindrical portion l. A ring-shaped protrusion 4a is provided on the inner periphery of one axial end of the cylindrical casing 4, a ring-shaped stator 5 is supported on the inner periphery, and a piezoelectric element 6 is bonded to the outer surface of the stator 5. As is well known, a traveling wave is generated in the stator 5 by applying a drive signal to the piezoelectric element 6 to cause it to vibrate. A space 7 is provided in the casing 4 at a position facing the piezoelectric element 6, and the space 7 is filled with cotton 8 so that the vibrations of the stator 6 are not directly transmitted to the casing 4.

Further, the cavity 7 is communicated with the outside through a through hole in the casing, and a conductive wire 9 for applying a drive signal passes through the through hole and a tip 8 in the cavity 7, and the conductive wire 9 is connected to the piezoelectric element 6 by soldering or the like. Connected.

A ring-shaped rotor 10 is stacked on the stator 5 on the side opposite to the piezoelectric element side. A slider material 11 is bonded to the stator side of the rotor 10 so that the rotor 10 is rotated by the traveling waves of the stator 5. A ring groove 12 is provided on the outer periphery of the rotor 10 to adjust its natural frequency, so that the natural frequency ratio with the stator 5 can be adjusted.

A ring-shaped guide 14 is attached to the opposite side of the rotor lO from the stator side through a cushioning material 13 such as rubber or cotton, and is configured to rotate together with the rotor 10. A further ring-shaped guide 15 is provided spaced apart from the ring-shaped guide 14 and is axially slidably mounted in the casing 4 . Note that the ring-shaped guide 15 has a spline configuration 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 these bearing balls 16 forms the two ring-shaped guides 1.
4.15 into ring-shaped concave grooves provided on the opposing surfaces. Further, a spring 17 is provided on the outside of the ring-shaped guide 15 in the axial direction, and is fixed to the casing 4 to press the rotor lO against the stator 5 via the 52 ring-shaped guides 14 and 15 and the bearing balls 16. There is. That is, by press-contacting the rotor 10 to the stator 5 in this way, the stator 5
The traveling wave of is made to effectively act on the rotor lO.

The base end side of the adjustment cylinder 2 extends to the inner circumference of the spring 17 and the ring-shaped guide 15, and a flange 2a is inserted between the two ring-shaped guides 14 and 15 at the base end.
is provided. This flange 2a has a plurality of through holes 18.
are provided, and the bearing balls 16 are provided in each through hole 18.
are rotatably fitted to each other. and rotor l
Due to the rotation of O, the bearing ball 16 rotates on its own axis and also revolves around the outer periphery of the fixed cylindrical portion l.

This revolution causes the diaphragm adjustment cylinder 2 to rotate, and rotates at a speed that is 1/2 of the rotational speed of the rotor IO.

[Effects of the Invention] According to the rotary speed reduction device of the present invention, the adjusting cylinder is rotated by the rotor of the ultrasonic motor at a rotational speed of 1/2 via the bearing ball, and the adjusting cylinder is slowly operated (rotating). In addition, when soldering the conductor wires to the piezoelectric element of the ultrasonic motor, a gap is provided and a piece is inserted between them, so that the vibration condition of the stator is maintained in good condition and the connection portion of the conductor wires is easily disconnected. Furthermore, by providing a ring for adjusting the natural frequency on the outer periphery of the rotor, the natural frequency ratio with the stator can be easily adjusted and the motor characteristics can be improved.

[Brief explanation of drawings]

The drawing is a half-sectional view showing the rotary speed reduction device of the same cylindrical body according to the present invention. l: Fixed cylindrical part 2. Adjustment cylinder 3: Ring type ultrasonic motor 5, stator 10. rotor

Claims (3)

[Claims] (1) In a device in which an adjusting cylinder is rotatably provided on the outer periphery of a fixed cylindrical part and the adjusting cylinder is rotationally adjusted by an ultrasonic motor, a ring type rotor is stacked on a ring stator to which a piezoelectric element is bonded. A casing of an ultrasonic motor is fixed to the outer periphery of a fixed cylindrical part, and a spring provided in the casing presses the rotor against the stator side via a ring-shaped guide member and a plurality of bearing balls, and the bearing balls are attached to the adjusting cylinder. The bearing ball is rotatably fitted into a plurality of through holes provided in the flange portion of the rotor, and as the rotor rotates, the bearing ball rotates on its own axis and also revolves around the outer periphery of the fixed cylindrical portion, and the adjustment cylinder is rotated by the revolution. Cylindrical rotary reduction device. (2) A void is provided in the casing at the outer surface of the piezoelectric element to be adhered to the stator of the ultrasonic motor, and the void is filled with cotton, and a conductive wire for applying a drive signal is passed through the cotton to generate a piezoelectric The rotational speed reduction device for a cylindrical body according to claim 1, characterized in that it is connected to an element. (3) The cylindrical rotary speed reduction device according to claim 1, wherein a ring groove for adjusting the natural frequency is formed on the outer periphery of the ring-shaped rotor.