JPH04217211A - Lens barrel - Google Patents

Abstract

PURPOSE:To provide a lens barrel for camera with a simple structure, and easy assembly and assembling adjustment by appropriately setting respective elements which constitute the lens barrel of a replacement lens. CONSTITUTION:There are provided a holding member 1c which rotatably holds a focus adjusting member 8 on the inner peripheral surface of a fixed cylinder 1 which is an element of a lens barrel, a key way 1g which is slidably fitted to a key for forwarding 8c provided on the outer peripheral surface of the lens holding member inserted so as to forward in an optical axis direction inside the fixed cylinder 1 in the inner peripheral surface of the fixed cylinder 1 in parallel to the optical axis, and a mount member 1a fixed to a camera body installed on the end part of the fixed cylinder 1.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a lens barrel for a photographic lens (interchangeable lens) used in a 35 mm film photographic camera, video camera, etc., and in particular to appropriately setting each element constituting the lens barrel. This invention relates to a lens barrel that simplifies the entire lens barrel and facilitates assembly and assembly adjustment.

0002

2. Description of the Related Art Conventionally, the main constituent members of a lens barrel of a photographic lens (interchangeable lens) attached to a camera body include a fixed barrel (exterior barrel) and a mount member attached to the camera body side. A focus adjustment member (focus adjustment ring) for focusing operation is rotatably provided in front of this fixed barrel, and a lens is held inside the fixed barrel, and the focus adjustment member is movable in the optical axis direction. A lens holding member that follows the lens, an aperture unit, a motor for driving the aperture, and other elements are provided.

Generally, the fixed cylinder and the mounting member are constructed as separate members from the viewpoint of assembly and assembly adjustment.

0004

[Problems to be Solved by the Invention] In conventional lens barrels, the fixed barrel and the mount member are constructed separately, so when assembling each member, first focus from the front side (object side) of the fixed barrel. Incorporate the adjustment member, and then fix each element such as a drive motor that rotates the focus adjustment member from the rear side of the fixed tube (image plane side, camera body side) and a gear train that transmits torque from the drive motor. It is built into a part of the tube and fixed. After that, a mount member is attached to the rear end of the fixed tube.

[0005] Conventional lens barrels were constructed using two exterior members, a relatively large fixed barrel and a mount member, which increased the number of parts, making the entire lens barrel complex and There is a problem in that the accompanying assembly and assembly adjustment become very complicated.

[0006] The present invention provides a lens barrel that simplifies the entire lens barrel and facilitates assembly and assembly adjustment by appropriately setting the structure of a fixed barrel and a mount member that are one element of the lens barrel. With the goal.

[0007]

[Means for Solving the Problems] The lens barrel of the present invention includes:
A holding member for rotatably holding the focusing member is provided on the inner circumferential surface of the fixed tube, and a holding member is provided on the outer circumferential surface of the lens holding member inserted so that it can move straight in the optical axis direction inside the fixed tube. A key groove that is slidably fitted into the linear key part is provided on the inner peripheral surface of the fixed barrel in a direction parallel to the optical axis, and a mount member that is attached to the camera body is provided at the end of the fixed barrel. It is a feature.

[0008]

[Embodiment] Fig. 1 is a sectional view of a main part of an embodiment of the present invention, Fig. 2
, 3 are perspective views of a portion of FIG. 1, respectively.

In the figure, reference numeral 1 denotes a fixed cylinder, which is molded from resin such as plastic. At the rear end of the fixed barrel 1, there is a bayonet claw 1a as a mount member for bayonet connection to the camera body (not shown), and on the inner peripheral surface of the tip end there is a holding member for bayonet connection to the reinforcing ring 2. A bayonet claw 1c and a groove 1d are provided. A plurality of key grooves 1g are provided on the inner circumferential surface of the cylindrical portion 1b of the fixed tube 1 in order to fit into key portions 9c implanted on the outer circumferential surface of the middle tube 9 that constitutes a part of the second lens holding member, which will be described later. It is provided in a direction parallel to the optical axis.

The reinforcing ring 2 is made of a metal material and is used to prevent the fixed cylinder 1 from deforming (deflecting). The reinforcing ring 2 has a groove 2a on its outer circumferential surface that engages with a bayonet claw 1c provided on the inner circumferential surface of the fixed barrel 1, and a bayonet claw 8a of a focus adjustment member 8, which will be described later, is fitted into its inner circumferential surface. A groove 2b is provided. After fitting the reinforcing ring 2 into the inner circumference of the fixed tube 1, it is rotated around the optical axis so that the side surface 2a1 of the groove 2a of the reinforcing ring 2 comes into contact with the stopper part 1h provided on the fixed tube 1. ing. This allows positioning in the optical axis direction and fixation to the fixed barrel 1 by frictional force with the inner circumferential surface of the fixed barrel 1.

Reference numeral 3 denotes a mount lid member, which is fixed to the rear side of the fixed tube 1 to prevent dirt, dust, etc. from entering the inside from the rear side of the fixed tube 1. A plurality of engagement claws 3b are integrally molded with resin on the outer periphery of the disk portion 3a of the mount lid member 3 so as to protrude from the outer periphery. This mount lid member 3 is integrated with the fixed cylinder 1 by fitting and fixing the engaging claw 3b into an engaging groove or hole provided in the fixed cylinder 1 using the elastic force of the resin.

4 is a changeover switch, and a focus adjustment member 8
Switching between automatic focus adjustment and manual focus adjustment is performed, and a switch spring 5 is attached to the protrusion 4a at one end with a screw 6.
is fixed. The changeover switch 4 is mounted in a groove 7a provided in the nameplate 7 so as to be movable in a direction parallel to the optical axis (in the direction of arrow 4b) by the elastic force of a switch spring 5. The nameplate 7 is fixed to the nameplate fixing surface 1f of the fixed tube 1 in such a manner that the protrusion 4a of the changeover switch 4 and the switch spring 5 are movable within the hole 1e provided in the fixed tube 1.

Reference numeral 8 denotes a focus adjustment member (focus adjustment ring), which is rotated around the optical axis manually or electrically by a driving force from an electromagnetic motor 14, which will be described later. A bayonet claw 8a is provided on a part of the outer peripheral surface of the focus adjustment member 8, and is held rotatably around the optical axis by fitting into a groove 2b provided in the inner peripheral surface of the reinforcing ring 2. There is.

Further, a plurality of protruding sliding surfaces 8b are provided on a part of the outer peripheral surface of the focus adjustment member 8, and the sliding surfaces 8b rotate in a fixed position while sliding on the inner peripheral surface of the reinforcing ring 2. That's what I do.

Reference numeral 9 denotes a middle cylinder, and a key part 9c for straight movement is provided on a part of the outer peripheral surface, and the key part 9c is fitted into a keyway 1g provided in the fixed cylinder 1. Thereby, the middle tube 9 is held so as to be movable in a direction parallel to the optical axis.

Reference numeral 10 denotes a front lens barrel, which constitutes a first lens holding member that holds the front lens group of the photographic lens. The middle tube 9 has an engagement hole 9f on its outer peripheral surface, and is fixed by fitting into a plurality of engagement claws 10c integrally formed on the front group lens barrel 10.

Reference numeral 11 denotes a rear lens barrel, which holds the rear lens group of the photographing lens, and has a bayonet claw 11a.
The bayonet is fixed to a bayonet groove 9a provided in the middle cylinder 9. The middle barrel 9 and the rear lens barrel 11 constitute a second lens holding member.

A cam surface 9b is provided at the front end of the middle tube 9, and a cam surface 10b is provided at the rear side of the front group lens barrel 10 to face the cam surface 9b of the middle tube 9. And the middle barrel 9 and the front lens barrel 10
By fixing the two cam surfaces 9b and 10b facing each other, the two cam surfaces 9b and 10b
A parallel cam groove space is formed that faces each other.

At this time, the cam surface 9b and the cam surface 10
A cam follower portion 8c extending from the focusing member 8 is fitted into the cam groove space formed by b, thereby forming a cam structure.

In this embodiment, by rotating the focus adjustment member 8 around the optical axis, the front group lens barrel 10, the rear group lens barrel 11, and the middle tube 9 integrated therewith are connected via the cam follower 8c.
and are moved in a direction parallel to the optical axis.

Reference numeral 12 denotes an aperture unit, and the aperture opening is controlled by a known electromagnetic motor 12a. The diaphragm unit 12 is fixed by fitting an engaging claw protruding from the middle cylinder 9 into the front disk surface of the diaphragm unit 12.

Reference numeral 13 denotes a main mounting component (board), which incorporates electrical components and is fixed to the inner tube 9 with screws. Electromagnetic motor 12a for driving the aperture unit 12
A coil terminal 12b extending from the main mounting component 13 is directly soldered to the main mounting component 13.

Reference numeral 14 denotes an electromagnetic motor, which drives the front lens barrel 10, the middle barrel 9, and the rear lens barrel 11, and is fixed to the motor mounting portion 9d provided on the outer periphery of the middle barrel 9 with screws. There is.

Reference numeral 15 denotes a gear train, which transmits the rotational torque of the electromagnetic motor 14. Each gear is fitted into a gear shaft (gear train shaft) 9e integrally formed in the middle cylinder 9, and is connected to the final stage gear. is configured to mesh with an inner gear 15f provided on a part of the inner peripheral surface of the focus adjustment member 8.

Next, the operation of the lens barrel of this embodiment will be explained. First, the lens barrel of this example is attached to the camera body. In the automatic focus detection mode, the electromagnetic motor 14 is driven based on a signal obtained by an automatic focus detection device provided on the camera body side. The rotational torque of the electromagnetic motor 14 is transmitted to the inner gear 15f provided on the inner peripheral surface of the focus adjustment member 8 via the gear train 15.
is rotated around the optical axis with respect to the fixed barrel 1.

At this time, the cam follower portion 8a of the focus adjustment member 8 is fitted into the cam groove space formed by the cam surface 9b of the middle tube 9 and the cam surface 10b of the front lens barrel 10 fixed to the middle tube 9. There is. Furthermore, the middle tube 9 is movable relative to the fixed tube 1 in a direction parallel to the optical axis due to a key structure consisting of a key portion 9c and a keyway 1g.

Therefore, as the focus adjustment member 8 rotates, the front lens barrel 10 and the middle barrel 9 move in the optical axis direction via the cam follower 8a. Further, the rear group lens barrel 11, which is bayonet-coupled to the middle tube 9, also moves integrally with the middle tube 9 in the optical axis direction at the same time.

Also, for manual focus adjustment, selector switch 4
By switching to the manual mode, a part of the gear train 15 is separated so that the rotational torque from the electromagnetic motor 14 is not transmitted to the focusing member 8. At this time, the same operation as described above is performed by manually rotating the focus adjustment member 8.

In this embodiment, by rotating the focus adjustment member 8 around the optical axis, the front lens barrel 10, the middle barrel 9, the rear lens barrel 11, and the motor on the outer periphery of the middle barrel 9 can be adjusted. Each element, such as the electromagnetic motor 14 incorporated in the mounting part 9d, the gear train 15 fitted into the gear shaft integrally molded in the middle tube 9, and the main mounting component 13 fixed to the middle tube 9, is integrally mounted parallel to the optical axis. The focus is adjusted by moving the camera in the direction.

[0030]

According to the present invention, each element is provided in the fixed barrel that constitutes a part of the lens barrel, and the mount member is also integrated, thereby simplifying the lens barrel structure and facilitating assembly. It is also possible to achieve a lens barrel that facilitates assembly and adjustment and improves economic efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a perspective view of a portion of FIG. 1;

FIG. 3 is a perspective view of a portion of FIG. 1;

[Explanation of symbols]

1 Fixed tube 2 Reinforcement ring 3 Mount lid member 4 Selector switch 5 Switch spring 7 Nameplate 8 Focus adjustment member 9 Middle tube 10 Front group lens barrel 11 Rear group lens barrel 12 Aperture unit 12a Electromagnetic motor 13 Main mounted parts 14 Electromagnetic motor 15 Gear train 1c bayonet claw 1d groove 1g keyway 8a Bayonet claw 8b Sliding surface 8c Cam follow part

Claims (1)

[Claims] Claim 1: A holding member for rotatably holding a focusing member is provided on the inner circumferential surface of a fixed barrel, and the lens holding member is inserted so as to be able to move straight in the optical axis direction inside the fixed barrel. A mount member is provided on the inner circumferential surface of the fixed tube in a direction parallel to the optical axis, the key groove slidably fitting into the linear key portion provided on the outer circumferential surface, and the mount member is attached to the camera body at the end of the fixed tube. A lens barrel characterized by being provided with.