JPH02210314A - Zoom lens driving mechanism - Google Patents

Abstract

PURPOSE:To correctly adjust a focal distance without a positional relation between a moving cylinder and fixing cam going wrong even when the moving cylinder receives external force by arranging a driving gear mechanism and a cam mechanism in the vicinity of a guide bar with sandwiching the guide bar. CONSTITUTION:A guide pipe 14 is provided on the upper corner part of a fixing cylinder 10, and a guide bar 16 is provided on the moving cylinder 12: The guide bar 16 is fitted into the guide pipe 14. A projection 20 is formed on the fixing cylinder 10 with respect to a guide groove 18 in the lower corner of the moving cylinder 12: The projection 20 is fitted into the groove 18 of the moving cylinder 12, and cooperates with the guide bar 16 and guides the moving cylinder 12. The driving gear mechanism 22 and the cam mechanism 20 are arranged with sandwiching the guide bar 16 of the moving cylinder 12. The guide bar 16 is strongly and fixingly formed. Thus, the positional relation between the moving cylinder 12 and the fixing cam 50 does not go wrong even when the moving cylinder 12 receives the external force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a zoom lens drive mechanism, and particularly to a zoom lens drive mechanism suitable for a compact camera.

[Conventional technology]

Recently, compact cameras incorporating a zoom lens mechanism have been proposed. In such compact cameras, a movable barrel is housed in a fixed barrel that is integrated with the camera body so that it can be moved back and forth, and the front group lens is attached to the front of the movable barrel, and the rear lens group is attached to the front of the movable barrel. The lens is moved back and forth with respect to the front lens group by a cam mechanism consisting of a cam lever rotatably attached to a movable barrel and a fixed cam fixed to a fixed barrel to adjust the focal length.

[Problem to be solved by the invention]

However, in the conventional zoom lens drive mechanism, the movable barrel extends forward much more than in a normal compact camera, so when the movable barrel receives an external force, the positional relationship between the movable barrel and the fixed cam becomes distorted, and the focal length The drawback was that it could not be adjusted accurately.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to propose a zoom lens drive mechanism that is strong against external forces.

[Means to accomplish the task]

In order to achieve the above object, the present invention provides a fixed tube, a movable tube slidably supported by the fixed tube via a guide bar, a drive gear mechanism for driving the movable tube, and a movable tube integrally connected to the movable tube. a moving front group lens; a rear group lens disposed in a movable tube and moved back and forth by a cam mechanism according to the amount of movement of the movable tube;
The zoom lens drive mechanism is characterized in that the drive gear mechanism and the cam mechanism are arranged near the guide bar with the guide bar in between.

[Function] The zoom lens drive mechanism of the present invention includes a drive gear mechanism and a cam mechanism that are arranged with a guide bar of a movable barrel in between. For this reason, the guide bar is usually strongly formed, and a drive gear mechanism and a cam mechanism are arranged near both sides of such a strong guide bar, so even if the movable tube receives external force, the movable tube remains stable. The positional relationship with the fixed cam will not be disturbed.

〔Example〕

Preferred embodiments of the zoom lens drive mechanism according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an exploded perspective view of a zoom lens barrel to which the zoom lens drive mechanism of the present invention is applied. tth
In a, a fixed barrel lO constituting the zoom lens barrel is integrally fixed to the front surface of the body (not shown), and a movable barrel 12 is slidably disposed within the fixed barrel 10. As shown in the figure, the fixed cylinder 10 and the movable cylinder 12 are formed into rectangular cylinder shapes, and the movable cylinder 12 can be moved back and forth with respect to the fixed cylinder 10 by a guide mechanism described below. That is, a guide bar 14 is provided at the upper corner of the fixed barrel 10, and a guide bar 1 is also provided in the movable barrel 12 correspondingly.
6 is provided, and the guide bar 16 is fitted into the guide vibe 14. Further, a guide groove 18 is formed in the axial direction at the lower corner of the movable cylinder 12, which is located diagonally above the guide bar 16.
A protrusion 20 is formed on the fixed cylinder 10 in correspondence with the guide groove 18 . The protrusion 20 fits into the groove 18 of the movable tube 12 and guides the movable tube 12 in cooperation with the guide bar 16. In this case, the main guide member is the guide bar 16, and the guide groove 18 and projection 20 function as a steady rest. For this reason, the guide vibrator 14 and the guide bar 16 are formed precisely and firmly.

As shown in FIG. 1, a sector gear 22 is rotatably attached to the inner surface of the fixed cylinder 10, and this sector gear 22 is connected to the movable cylinder 10.
It engages with a rack 28 disposed axially near a corner of. Therefore, the fan-shaped gear 22 is
When the movable cylinder 12 is rotated, the movable cylinder 12 is moved back and forth with respect to the fixed cylinder IO via the rack 28 with the fan-shaped gear 22.

A front group lens 30 is movably attached to the front part of the movable barrel 12. Further, behind the movable barrel 12, as shown in FIG. 2, a rear group lens 32 is arranged so as to be movable back and forth.

That is, the lens support frame 34 of the rear group lens 32 is connected to the guide bar 3.
6 and is moved back and forth within the movable cylinder 12.

Next, the cam mechanism for moving the rear group lens 32 will be explained. A pin 38 is provided protruding from the side of the lens support frame 34, and this pin 38 is arranged in a long hole 39 formed in the axial direction on the side of the movable cylinder 12. On the other hand, a drive lever 40 formed in a substantially doglegged shape is pivotally supported on the side surface of the movable cylinder 12 so as to be swingable about a shaft 42, and is urged to rotate clockwise by a spring 44. A long hole 46 is formed at the upper end of this drive lever 40, and a pin 38 of the lens support frame 34 is located therein. Therefore, when the drive lever 40 is swung around the shaft 42, the lens support frame 34 moves toward the movable barrel 12.
It is designed to move back and forth within the space. On the other hand, a cam 5 is provided inside the side surface of the fixed cylinder IO corresponding to the elongated hole 40 of the movable cylinder 12.
A driven pin 54 protruding from the lower part of the drive lever 40 is in contact with the cam surface 52 of the cam 50 . Therefore, when the movable barrel 12 moves back and forth within the fixed barrel 10, the amount of rotation of the drive lever 40 is controlled by the cam surface 52 of the cam 50, and this cam surface 52 adjusts the focal length according to the amount of extension of the movable barrel 12. It is formed like this.

According to the zoom lens drive mechanism according to the present invention configured as described above, the oval shape 22 is swung by the drive mechanism (not shown), and the movable barrel 12 is accordingly moved back and forth within the fixed barrel 10. Also, as the movable tube 12 moves, the rear group lens 3
2 moves relative to the front lens group 30, and the focal length il? Make adjustments.

On the other hand, the fan-shaped gear 22, the drive lever 40a, and the cam 50 are arranged near the guide bar 16 with the guide bar 16 in between. Therefore, even if the movable cylinder 12 receives external force in the extended state, the drive mechanism 22 and the cam mechanism are located near the strong guide bar 16, so the positional relationship between the movable cylinder 12 and the fixed cam 50 will not be disturbed. Therefore, even if the movable barrel 12 receives an external force or the like, the focal length can be adjusted accurately.

〔Effect of the invention〕

As explained above, according to the zoom lens drive mechanism according to the present invention, the movable barrel is arranged so as to be movable back and forth with respect to the fixed barrel via the guide bar, and the drive gear mechanism of the movable barrel and the lens movement of the rear group are Since the cam mechanism is located near the guide bar, it is possible to propose a strong lens drive mechanism and cam mechanism for the movable barrel.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a zoom lens barrel to which a zoom lens drive mechanism according to the present invention is applied, and FIG. 2 is a side view, partially in section, of the movable barrel shown in FIG. 10... fixed tube, 12... movable tube, 14.
...Guide pipe, 16...Guide bar, 2
2... Sector gear, 32... Rear group lens, 40.
... Drive lever, 50... cam.

Claims (2)

[Claims] (1) A fixed tube, a movable tube slidably supported by the fixed tube via a guide bar, a drive gear mechanism that drives the movable tube, a front lens group that moves integrally with the movable tube, and a movable tube. a cam mechanism consisting of a cam lever rotatably attached to a tube and a fixed cam fixed to a fixed tube; and a rear group lens arranged in a movable tube and moved back and forth by the cam mechanism according to the amount of movement of the movable tube. , wherein the drive gear mechanism and the cam mechanism are arranged near the guide bar with the guide bar in between. (2) The fixed tube and the movable tube are formed into a rectangular tube shape, the guide bar is arranged at a corner of the rectangular tube sandwiched between the top surface and one side of the movable tube, and the drive gear mechanism is arranged on the top surface of the movable tube. 2. The zoom lens drive mechanism according to claim 1, wherein the cam mechanism is disposed on one side of the movable barrel.