JPH01178909A - Motor-driven zoom lens device - Google Patents

Abstract

PURPOSE:To decrease the number of components, to simplify the structure around a lens barrel, and to reduce the axial space of a motor incorporated part by arranging two ultrasonic motors back to back with each other and allowing a stator holding frame to move freely only in axially directions. CONSTITUTION:A stator 8 for focus driving and a stator 2 for zoom driving are arranged back to back with each other and held by the one stator holding frame 1. Further, the stator holding frame 1 is allowed to move only in the axial directions and pressing force for rotors for zoom driving 3 and focus driving 9 and the stators 2 and 8 is obtained from the pressure of one spring washer 7. Consequently, the number of components is decreased, the structure around the lens barrel 1 is simplified, and the necessary space is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric zoom lens device used in a television camera or the like.

BACKGROUND OF THE INVENTION FIG. 2 is a sectional view of the main parts of a conventional zoom lens device.

In FIG. 3, 21 is a stator holding frame that holds a stator 22 for zoom driving. 23 is a zoom drive rotor, and steel balls 24. It is pressed against the zoom drive stator 22 via the fixed frame 25 by a spring washer 27 and a pressure adjustment spacer 26 . Further, 29 is a stator holding frame, and a stator 30 for focusing and driving.
is held. 31 is a focus and drive rotor, and a copper ball 24. Spring washer 2 via fixed frame 25
7 and the pressure adjustment spacer 26, it is pressed against the focus drive stator 30. Reference numeral 20 and 28 denote a zoom lens barrel, and a drive rotor 23 has a notch partially provided inside and is loosely fitted with a zoom drive pin 31. The focus ring drive pin 33 fixed to the focus ring 34 is also loosely fitted into the U groove of the focus ring drive plate 32, which is still fixed to the focus drive rotor 31.

Next, the operation of the above conventional example will be explained. By applying an ultrasonic frequency voltage to the piezoelectric element of the zoom drive stator 22 and generating a traveling wave in the vibrating body, the spring washer 27 and the pressure adjustment spacer 26 are used to drive the zoom via the steel ball 24 and the fixed frame 25. The zoom drive rotor 23, which is pressed against the stator 22, rotates. At the same time, the zoom drive pin 31 fitted into the notch inside the zoom drive rotor 23 rotates to perform a zoom operation.Similarly, by generating a traveling wave in the vibrating body of the focus drive stator 30, the steel ball 2 and a focus that is pressed against the focus drive stator 30 by the spring washer 27 and the pressure adjustment spacer 26 via the fixed frame 25;
The drive rotor 31 rotates. At the same time, rotation is transmitted between the focus ring drive plate 32 fixed to the focus drive rotor 31 and the focus ring drive bin 33 fixed to the focus ring 34, the focus ring 34 rotates, and the focus operation is performed. A conventional electric zoom lens device can also rotate an ultrasonic motor for zooming, focusing, and focusing.

Problems to be Solved by the Invention However, in the conventional electric zoom lens device described above, the spring washer for pressing the rotor and stator of the ultrasonic motor and the stator holding frame are separate for the zoom drive motor and the focus drive mode. This required a large number of parts, a complex structure around the lens barrel, and a large space in the axial direction for the motor assembly.

Means to Solve the Problems In order to achieve the above object, the present invention arranges two ultrasonic motors back to back around a stator holding frame, so that the stator holding frame can freely move only in the axial direction. This is how it was done.

Therefore, according to the present invention, two stators are held by one stator holding frame by arranging two ultrasonic motors back to back, and furthermore, the stator holding frame can be moved only in the axial direction. This has the effect of reducing the number of parts such as the stator holding frame and pressurizing spring washers, reducing the space required for the lens barrel opening, and simplifying the structure.

Embodiment FIG. 1 is a sectional view of main parts showing the structure of an embodiment of the present invention.

FIG. 2 similarly shows a perspective view showing the configuration of an embodiment of the present invention.

In FIGS. 1 and 2, 1 is a stator holding frame that holds a zoom drive stator 2 and a focus drive stator 8. In FIG. Further, a slide pin 13 screwed into the stator holding frame 1 is loosely fitted into an elongated hole opened in the lens barrel 12. The steel ball 4 exists between the zoom drive rotor 3 and the V-groove of the fixed frame 5, and similarly exists between the focus drive rotor 9 and the V-groove of the fixed frame 11. Reference numeral 6 denotes a pressure adjusting spacer, which adjusts the pressure of the spring washer 7 by changing its thickness. A focus ring drive plate 15 is attached to the focus drive rotor 9, and a focus ring drive pin 1 fixed to the focus ring 17 is attached to the U groove of the focus ring drive plate 15.
6 is loosely fitted.

A portion of the zoom drive rotor 3 has a notch inside, and the zoom movement pin 14 is loosely fitted therein.

Next, the operation of the above embodiment will be explained. According to the above embodiment, the pressure of the spring washer 7 adjusted by the pressure adjusting washer 6 presses the zoom drive rotor 3 against the zoom drive stator 2, and generates a traveling wave in the vibrating body of the zoom drive stator 2. If this is done, the zoom drive rotor 3 will rotate. The notch provided inside the rotor 3 is
Since it is fitted with the zoom drive bin 14, a zooming operation can be performed. Similarly, the focus drive stator 8 is pressed against the focus drive rotor 9 by the pressure of the spring washer 7, so if a traveling wave is generated in the vibrating body of the focus drive stator, the focus drive rotor 9 will rotate. do. A focus ring drive plate 15 fixed to the focus drive rotor 9 rotates a focus ring drive pin 16, thereby moving the focus ring 17 back and forth.

In this way, according to the embodiment described above, the stator holding frame 1 is movable only in the axial direction. In addition, the stators for focus drive and zoom drive are arranged back to back and held by one stator holding frame 1, which reduces the number of spring washers, spacers, and holding frame parts. This has the effect of reducing the space required around the lens barrel and simplifying the structure.

Effects of the Invention As is clear from the above embodiments, the present invention has the following advantages.

(1) The focus drive stator and zoom drive stator are placed back to back, and the two stators are held by one stator holding frame, reducing the number of parts.
The structure of the lens barrel can be simplified.

(2) The stator holding frame is movable only in the axial direction, and the pressing force for the rotor and stator for zoom drive and focus drive is obtained from the pressure of one spring washer, reducing the number of parts. The space required for rotating the lens barrel can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electric zoom lens device according to an embodiment of the present invention, FIG. 2 is a perspective view thereof, and FIG. 3 is a sectional view of a conventional electric zoom lens device. DESCRIPTION OF SYMBOLS 1... Stator holding frame, 2... Stator for zoom drive, 3... Rotor for zoom drive, 4... Steel ball 5...
・Fixed frame, 6... Pressure adjustment washer, 7... Spring washer, 8. Puff orcus drive stator 9...
・Focus drive rotor, 11...Fixed frame, 12・
... Lens barrel, 13... Slide pin, 14... Zoom drive pin, 15゛... Focus ring drive plate, 16.
・・Focus ring drive pin, 17 ・・Name of focus ring agent Patent attorney 2nd year; Toshio Oo and 1 other person Figure 1 I Figure 3

Claims (2)

[Claims] (1) In a stator having two piezoelectric elements and a vibrating body with a phase shift of 90 degrees, a voltage of an ultrasonic frequency with a temporal phase shift of 90 degrees is applied to the piezoelectric elements, and the voltage of an ultrasonic frequency with a phase shift of 90 degrees in time is applied to the piezoelectric elements, An electric zoom lens device in which two ultrasonic motors are arranged back to back with a stator holding frame in between, which frictionally drives a rotor that is in pressure contact with the stator using the generated traveling waves. (2) The electric zoom lens device according to claim 1, wherein the stator holding frame is movable only in the axial direction.