JPH09318863A - Photographic optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photographic optical device capable of performing sure driving by preventing tooth-skipping in a gear used for driving a photographic optical system. SOLUTION: A driving gear 15 is driven by a motor unit 11, rotates in a direction shown by an arrow A, an inner gear 16 is engaged and driven in a direction shown by an arrow B, driven to an end part, then a stopper 19 abuts on a bearing 17, and the gear 16 is stopped. At this time, since the bearing 17 is not vibrated in a direction opposite to the B direction, the tooth-skipping does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing optical device mainly mounted on a camera or the like, and more particularly to a gear jump prevention mechanism of a gear used for driving a photographing optical system. is there.

[0002]

2. Description of the Related Art In the case of focusing or zooming of such a photographing optical system, a gear is conventionally used as a means for transmitting a driving force from a driving source when driving the lens group. For example, as schematically shown in FIG. 11, when the drive gear 51 rotates in the direction of arrow A, the movement is transmitted to the gear portion 53 provided in the member that drives the lens group by the meshing of the teeth, and the gear portion 53. Is driven in the direction of arrow B. A stopper 54 is provided at the end of the drive destination, and stops when the gear 53 comes into contact with the stopper 54. When the rotation of the drive gear 51 also stops due to the stop of the gear portion 53, the rotation stop is detected by some means and the drive of the drive gear 51 is stopped.

[0003]

However, in the above-described configuration, an excessive force is applied between the detection of the rotation stop of the drive gear 51 and the stop of the drive by the rotation shaft 5.
When the bearing No. 2 is swung in the direction of arrow C or the like, tooth jump may occur between the drive gear 51 and the gear portion 53. The present invention solves the above-mentioned disadvantages,
In the gear used to drive the shooting optics,
An object of the present invention is to provide a photographing optical device that can be reliably driven by providing a tooth jump prevention mechanism.

[0004]

In order to achieve the above object, in the present invention, when a gear portion provided in a member for driving a lens group is meshed and driven by a driving gear forming a part of a driving means, By bringing the bearing portions of the drive gear into contact with the stopper members provided at both ends of the gear portion, the operation of the member that drives the lens group is stopped.
Further, a cover for covering the drive gear is provided on the bearing portion, and the stopper member comes into contact with the cover, whereby the drive gear is braked through the bearing portion and the operation of the member for driving the lens group is performed. Protects the drive gear.

Further, the bearing portion is provided on the fixed cylinder arranged on the outer periphery of the member for driving the lens group, whereby rattling of the drive gear is prevented, and the lens is secured. Drive to.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the appearance of a camera in which an interchangeable lens 61 as a photographing optical device to which the present invention is applied is attached to a camera body 60.
FIG. 2 is a perspective view schematically showing a state in which main components of the photographing optical device of the embodiment are disassembled and arranged in the optical axis direction. In FIG. 1, reference numeral 1 denotes a first moving frame disposed at the front of the photographing optical apparatus, and 2 denotes a second moving frame, in which lens groups L1 and L2 (not shown) are held, respectively. I have. Reference numeral 3 denotes a cam cylinder. The first moving frame 1 and the second moving frame 2 are fitted inside the cam cylinder 3, and pins 5 and 6 provided respectively are spirally provided on the cam cylinder 3. Cam grooves 7, 8
Through each.

Further, 9 is a fixed cylinder, and 10 is a cam groove linearly provided in the fixed cylinder 9. The cam cylinder 3 is fitted inside the fixed cylinder 9 and penetrates the cam grooves 7, 8. The pins 5 and 6 further penetrate the cam groove 10. In addition, 4 is a holding ring, 1
Reference numeral 1 denotes a motor unit having a built-in motor and a driving gear 15 rotated by the motor. The motor unit 12 includes a cover for covering a rear portion of the photographing optical device. In addition, an external member that covers the cam groove 10 is provided on the outer periphery of the fixed cylinder 9, but is omitted in the drawing.

FIG. 3 is a vertical sectional view schematically showing a state in which the photographing optical device is assembled, and FIG. 4 is a vertical sectional view schematically showing a state in which the lens group is driven. In FIG. 3, when the drive gear 15 is driven by the motor unit 11, the inner gear 16 partially provided on the inner surface of the cam cylinder 3 is engaged and driven, and the cam cylinder 3 is moved along the optical axis X.
Rotate around.

At this time, the cam grooves 7 and 8 spirally provided on the cam barrel 3 push the pins 5 and 6 provided on the first moving frame 1 and the second moving frame 2, respectively. Since 6 moves along a cam groove 10 linearly provided on the fixed barrel 9, the first moving frame 1 and the second moving frame 2 are driven in the optical axis direction as shown in FIG. , L2 are similarly driven. At this time, the amount of movement between the first moving frame 1 and the second moving frame 2 is different based on the difference in the shape of the cam grooves 7 and 8, and therefore, as shown in FIG. The interval will open.

FIG. 5 is a diagram schematically showing a state near the drive gear 15 from the optical axis direction. A cover 18 provided on a bearing 17 extending from the fixed cylinder 9 is provided with an inner gear 16.
By contacting the stoppers 19 provided at both ends of the
It has a function of stopping the operation of the inner gear 16 and the rotation of the cam barrel 3 and a role of protecting the drive gear 15. Reference numeral 20 denotes a sliding member which is provided integrally with the cam barrel 3 so as to be bridged between the stoppers 19, 19,
When the drive gear 15 is lifted, it comes into contact with the bearing 17 to prevent the drive gear 15 from escaping. In order to maintain the close relationship with the bearing 17 when the cam barrel 3 rotates, the sliding member 20 has an arc shape that is concentric with the fixed barrel 9. Incidentally, FIG.
In the above, the sliding member 20 is close to the bearing 17, but it may be always in contact with the bearing 17.

FIG. 6 is a perspective view schematically showing a state in which stoppers 19 for contacting the bearing 17 are provided at both ends of the inner gear 16. In FIG.
Is driven by the motor unit 11 and rotates in the direction of the arrow A, the inner gear 16 meshes and drives in the direction of the arrow B. When driven to the end, as shown in FIG. 7, the stopper 19 comes into contact with the bearing 17, and a force canceling each other acts as shown by an arrow.
6 stops. At this time, since the bearing 17 is not shaken to the right side of the drawing, tooth skipping due to it is not caused.

This is the same when the drive gear 15 rotates in the opposite direction, the inner gear 16 moves in the direction opposite to the arrow B direction, and comes into contact with the stopper 19 at its end. When the stopper 19 comes into contact with the bearing 17 and the inner gear 16 stops, a force for stopping the drive gear 15 acts on the drive gear 15 and the drive gear 15 stops. When this stop is detected by the detecting means (not shown), the motor drive signal is not given, and the motor (and the drive gear 1) are stopped.
The driving of 5) stops.

FIG. 8 shows a case where a sliding member 20 is further provided. In this case, similarly, when the drive gear 15 is driven by the motor unit 11 and rotates in the direction of arrow A, the inner gear 16 meshes and drives in the direction of arrow B. At this time, the bearing 17 and the sliding member 20 are close to or in contact with each other. Further, as shown in FIG. 9, the driving gear 15 receives a reaction force F from the inner gear 16 at the time of driving. Therefore, when considering the component forces Fy and Fx, Fy is a force in the direction of disengagement of the gears. And Fx is expressed as a reaction of the force that drives the inner gear 16 in the longitudinal direction. Normally, the component forces Fy and Fx are absorbed by the bearing 17.

At this time, when the user of the camera forcibly stops the inner gear 16 by applying some external force or the like, the driving force continues to act on the driving gear 15, so that the force F increases and the component force Fy. Also increases, so bearing 1
Depending on 7 alone, it cannot be absorbed, and the gears may be disengaged and cause tooth skipping.
If the sliding member 20 is present, the bearings 17 come into contact with each other, as shown in FIG. 10, so as to cancel each other out, as shown in FIG. Can be.

In this example, when the inner gear 16 is driven to the end portion, the component force Fx is absorbed by the inner gear 16 contacting an external stopper instead of the bearing 17 contacting the stopper 19. You may go by letting it. This is because, as long as the sliding member 20 is present, there is no risk of tooth jumping even at the end portion. With the tooth jump prevention mechanism as described above, it is possible to reliably drive the photographing optical system.

[0016]

As described above, according to the present invention,
In the gear used to drive the shooting optics,
By providing the tooth jump prevention mechanism, it is possible to provide a photographic optical device that can be reliably driven. The tooth jump prevention mechanism is a stopper member provided at both ends of the gear portion when the gear portion provided in the member that drives the lens group is driven to mesh by the drive gear that forms a part of the drive means. The operation of the member that drives the lens group is stopped by bringing the bearing portion of the drive gear into contact.

According to another aspect of the present invention, there is provided a cover for covering the drive gear on the bearing portion, and the stopper member is brought into contact with the cover to brake the drive gear via the bearing portion. By applying a configuration that causes the operation of the members that drive the lens group to stop,
Protect the drive gear.

Further, in the photographing optical device according to the present invention, the bearing portion is provided in the fixed cylinder arranged on the outer periphery of the member for driving the lens group, whereby the rattling of the drive gear is performed. It prevents sticking and drives the lens group reliably.

[Brief description of drawings]

FIG. 1 is a perspective view showing the appearance of a camera to which a photographing optical device according to the present invention is attached.

FIG. 2 is an exploded perspective view of main components constituting the photographing optical device of the present invention.

FIG. 3 is a longitudinal sectional view schematically showing a state where the photographing optical device is assembled.

FIG. 4 is a longitudinal sectional view schematically showing a state where a lens group is driven.

FIG. 5 is a diagram schematically showing a state near a driving gear from an optical axis direction.

FIG. 6 is a perspective view schematically showing a state in which a stopper that comes into contact with a bearing is provided.

FIG. 7 is a diagram schematically showing a state in which a stopper is in contact with a bearing.

FIG. 8 is a perspective view schematically showing a state in which a sliding member to be brought close to or in contact with the bearing is provided.

FIG. 9 is an explanatory diagram of a force applied to a drive gear.

FIG. 10 is a view schematically showing a state in which a sliding member is in contact with a bearing.

FIG. 11 is a diagram schematically showing a state of conventional gear driving.

[Explanation of reference symbols] 1st moving frame 2 2nd moving frame L1, L2 lens group 3 cam barrel 4 retaining ring 5,6 pin 7,8,10 cam groove 9 fixed barrel 11 motor unit 12 cover 15 drive gear 16 inner Gear 17 Bearing 18 Cover 19 Stopper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toyonen Kawasaki 2-3-13 Azuchi-cho, Chuo-ku, Osaka City Osaka International Building Minolta Co., Ltd. (72) Inventor Sadamitsu Osawa 73 Nanase, Nakano-shi, Nagano Prefecture Co-China Research and Development Division

Claims (3)

[Claims] 1. A photographic optical system, a first holding member for holding the photographic optical system, and a first holding member for holding the first holding member and driving itself during focusing or zooming of the photographic optical system. A photographic optical device comprising: a second holding member that drives a first holding member in the optical axis direction of the photographic optical system; and a drive unit that drives the second holding member,
When a gear part partially provided in the second holding member in the circumferential direction is meshingly driven by a drive gear forming a part of the drive means, the drive gear is provided to stopper members provided at both ends of the gear part. The photographic optical device is characterized in that the operation of the second holding member is stopped by abutting the bearing portion of the. 2. A cover for covering the drive gear is provided on the bearing portion, and the stopper is brought into contact with the cover, whereby the drive gear is braked through the bearing portion, and the second holding member is provided. The photographic optical device according to claim 1, wherein the operation of is stopped. 3. The photographing optical device according to claim 1, wherein the bearing portion is provided on a fixed cylinder arranged on an outer circumference of the second holding member.