JP2003029120A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain miniaturization, reduction of weight and reduction of cost by simplifying a structure, reducing the number of parts and reducing assembly man-hours and also to surely perform the rotation regulation of a specified frame. SOLUTION: A float key 22 possesses protrusions 22b projectingly provided in three peripheral directions from a base end part 22a, formed into a ring-like shape and fitted in straight advance guide grooves 3a, which is formed to be long lengthwise in the optical axis direction at a fixed frame 3, to slid freely, linear arm parts 22c extended forwardly at the inside of a lens barrel 1 from the base end part 22a and guide grooves 22d formed long in the lengthwise direction along the linear arm parts 22c. Then, a float key guide protrusion 21, provided at a second group frame 10, is engaged with and is slid in the guide groove 22d of the float key 22, so that the rotation of the second group frame 10 about and optical axis is regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a camera or the like, in which a plurality of lens frames holding a photographing lens group and the like move in the optical axis direction.

[0002]

2. Description of the Related Art Conventionally, in a lens barrel of a camera or the like composed of a plurality of lens frames, a fixed frame fixed to the camera body, a rotation relative to the fixed frame, and a rotation relatively moving in the optical axis direction. The frame includes a straight frame, a lens frame, and the like, which are restricted from rotating relative to the fixed frame and relatively move in the optical axis direction.

In such a conventional lens barrel, regulation of relative rotation of a specific frame is achieved by providing a key member such as a float key. For example, in Japanese Unexamined Patent Publication No. 5-188273, a plurality of parts such as screws and receiving members are used at the rear end of a cam barrel that moves back and forth in the optical axis direction while rotating, and moves in the optical axis direction together with the cam barrel. However, a float key provided so as to be rotatable relative to the cam cylinder is disclosed.

[0004]

However, as described above, in the conventional key member, in order to provide it, that is, the key member is provided so as to move back and forth in the optical axis direction together with the rotating frame and to be rotatable relative to this frame. Therefore, multiple parts are required,
There was a problem that the assembly man-hour also became complicated. The increase in the number of parts hinders the reduction in size and weight of the lens barrel, and the increase in the number of parts and the number of assembling steps leads to an increase in cost.

The present invention has been made in view of the above circumstances, and has a simple structure, a small number of parts, a small number of assembling steps, a reduction in size and weight and a cost reduction, and a rotation regulation of a specific frame. It is an object of the present invention to provide a lens barrel capable of reliably performing the above.

[0006]

A lens barrel according to claim 1 of the present invention comprises a first frame, a second frame which is relatively movable with respect to the first frame in the optical axis direction, and the first frame. Relative rotation with respect to one frame and relative movement between the third frame for moving the second frame in the optical axis direction by relatively moving in the optical axis direction, and relative rotation between the first frame are restricted, and It is characterized in that it is provided with a key member which is arranged so as to be relatively movable in the optical axis direction with respect to the first frame and the third frame, and which restricts relative rotation of the second frame.

That is, in the lens barrel according to claim 1, the third frame moves relative to the first frame in the optical axis direction relative to the first frame and moves in the optical axis direction. . At this time, the key member regulates the relative rotation with respect to the first frame and regulates the relative rotation with respect to the second frame, and as a result, the second frame regulates relative rotation with respect to the first frame. , Are relatively moved in the optical axis direction. Since the key member is arranged so as to be relatively movable in the optical axis direction with respect to the first frame and the third frame, the key member can be relatively rotatable with respect to the third frame as in the conventional case. Since it is not necessary to provide it along with the third frame so as to be movable in the optical axis direction, there is no need for parts to attach the key member to the third frame, the number of assembly steps can be reduced, and the size and weight can be reduced and the cost can be reduced. Is possible.

A lens barrel according to a second aspect of the present invention is characterized in that, in the lens barrel according to the first aspect, the key member is linearly moved by the second frame. That is, the key member is arranged so as to be relatively movable in the optical axis direction with respect to the first frame and the third frame,
If necessary, the second frame is linearly moved to regulate the relative rotation of the second frame.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of the present invention. FIG. 1 is a vertical sectional view along an optical axis in a telephoto state of a lens barrel as a photographing lens provided in a camera, and FIG. -A sectional view, FIG. 3 is an exploded perspective view of the lens barrel, and FIG. 4 is a vertical sectional view along the optical axis in the retracted state of the lens barrel of FIG.

In these drawings, reference numeral 1 denotes a lens barrel, and this lens barrel 1 is zoom-driven (variable-magnification drive) by a zoom drive system (not shown) composed of a motor, a gear train, and the like. It

The lens barrel 1 is fixed to a fixed frame 3 as a first frame which is fixedly supported by covering the outer side of the aperture 2a of the camera body 2, and is rotatably supported with respect to the fixed frame 3. The rotation frame 4 as a third frame is supported so as to be able to move forward and backward in the optical axis direction with respect to the rotation frame 4 in a state where rotation is restricted, and is also moved forward and backward in the optical axis direction relative to the fixed frame 3. It is configured to have a rectilinear frame 5 that is movably supported. In FIG. 1, reference numeral 6 indicates a film set in the camera body 2, and reference numeral 7 indicates a pressure plate for the film 6.

Inside the straight-moving frame 5, the first group lens 9 having an optical axis O on the object side (hereinafter "front side") and held by the first group frame 8 and the camera body 2 side (hereinafter "rear side"). ) Also the optical axis O
And a known focusing drive for driving the first group frame 8 relative to the rectilinear frame 5 in the direction of the optical axis O and the second group lens 11 held by the second group frame 10 as a second frame. A mechanism and a known shutter unit (neither is shown) are stored.

The fixed frame 3 and the rotary frame 4 are connected by a helicoid screw. That is, the female helicoid screw 12 is formed on the inner surface of the fixed frame 3, while the male helicoid screw 1 is formed on the rear outer surface of the rotary frame 4.
3 are formed, these female helicoid screw 12 and male helicoid screw 13 are screwed together, and the rotary frame 4 is fixed frame 3
It is supported so that it can move back and forth while rotating.

Inside the front end of the fixed frame 3, the rotary frame 4 is allowed while allowing the rotary frame 4 to move smoothly.
A light-shielding rubber 14 having a dust-proof, water-proof, and light-shielding function is attached to close the gap between and.

The rotating frame 4 and the rectilinear frame 5 are connected by a cam mechanism. That is, six cam grooves 15 are spirally formed on the inner surface of the rotating frame 4, and three of these cam grooves 15a have the same shape on the inner surface of the same circumference of the rotating frame 4. The other three cam grooves 15b, which are formed at substantially equal intervals in the circumferential direction, have the same shape as the cam grooves 15a on the same inner circumferential surface of the rotary frame 4 as described above, and are displaced from each other in the optical axis direction. In addition, they are formed at positions equidistant from the cam grooves 15a in the circumferential direction of the inner surface of the circumference. The three cam grooves 15a and the other three cam grooves 15b are formed at positions where the end point and the start point are displaced from each other in the circumferential direction by a predetermined amount.

Further, on the outer peripheral surface on the rear side of the rectilinear frame 5,
Six cam followers 1 corresponding to the above six cam grooves 15
6 are provided in a protruding manner, and the six cam followers 16 are engaged with and slidably contact with the six cam grooves 15, respectively, so that the rectilinear frame 5 is divided into two groups described later by a float key 22 described later. The rotation is indirectly controlled via the frame 10 and is supported so as to be able to move forward and backward with respect to the rotary frame 4.

A second group frame 1 is provided on the inner peripheral surface of the rotary frame 4.
Three cam grooves 18 for advancing and retracting 0 in the optical axis direction are formed. Then, the three cam followers 17 of the two groups extending in the radial direction from the second group frame 10 for engaging with the cam grooves 18 for the second group are provided on the rectilinear frame 5 at the three rectilinear grooves 5a in the optical axis O direction. 2 through the cam groove 1
The second group frame 10 is moved forward and backward in the optical axis O direction while restricting the rotation of the rectilinear frame 5 by engaging with 8 and making sliding contact. As described above, the rotation of the second group frame 10 is restricted by the float key 22 described later.

Further, on the inner peripheral surface of the front end of the rotary frame 4, the linear frame 5 is allowed while allowing the linear frame 5 to move smoothly.
A light-shielding rubber 19 having a dust-proof, waterproof, and light-shielding function is attached to close the gap between the and.

As shown in FIG. 2, the second group frame 10 has three projecting portions 20 formed at three locations on the outer peripheral surface so as to project toward the rectilinear frame 5. The rear end inner peripheral surface of the rectilinear frame 5 has six protrusions 5b in the radial direction. These protrusions 5b sandwich one protrusion 20 between the two protrusions 5b and restrict the relative rotation of the rectilinear frame 5 and the second group frame 10 around the optical axis, so that the rectilinear frame 5 and the second group frame 10b. It is possible to move relative to 10 in the optical axis direction.

Further, the second group frame 10 is provided with two plate-shaped guide projections 21 for a float key projecting from the rear end portion of the outer periphery so as to be substantially opposed to each other. It is engaged with the guide groove 22d of the linear arm portion 22c of the key 22.

The float key 22 serves as a key member and has a ring-shaped base end portion 22a,
The ring-shaped center has an oval-shaped opening 22e which also functions as a flare stop. In addition, the base end 22a
Projections 2 projecting radially outward from three locations
With 2b. The protruding portion 22b is fixed to the fixed frame 3
And is slidably fitted in a straight guide groove 3a that is vertically long in the optical axis direction. Furthermore, the float key 22 is
A linear arm portion 22c extending from 2a in the front optical axis direction in the lens barrel 1 and a vertically long guide groove 22d (a long hole having a constant width) formed in the linear arm portion 22c in the optical axis direction are provided. Have The guide projections 21 for the float key provided on the second group frame 10 engage and slide in the guide grooves 22d of the float key 22 to restrict the rotation of the second group frame 10 around the optical axis. In addition, the straight frame 5 in FIGS. 1 and 4
The reference numeral 23 shown in the part indicates the storage space of the float key 22 when the lens barrel 1 is retracted.

Next, the specific operation of the float key 22 will be described with reference to the movement of the lens barrel 1 from the retracted state in FIG. 4 to the telephoto state in FIG. First, in the retracted state of the lens barrel 1 shown in FIG. 4, the rotary frame 4 is housed along the helicoid screw in the fixed frame 3 for substantially the entire length.
The rear end face of the float key 22 is positioned so that the base end 22a of the float key 22 is substantially sandwiched between the rear end face and the camera body 2.

Also, in the rectilinear frame 5, the six cam followers 16 are guided to the retracted position which has been set in advance by the six cam grooves 15 of the rotary frame 4, leaving a part of the tip end on the object side. The second group frame 10 is housed inside the rotary frame 4, and the three second groups of cam followers 17 are also guided to the retracted position set in advance by the three second group cam grooves 18 of the rotary frame 4. The rear of the rotary frame 4 is retracted. At this time, the float key guide projection 21 of the second group frame 10 is positioned behind the guide groove 22d of the float key 22, and the tip portion of the linear arm portion 22c of the float key 22 is retracted to the rectilinear frame 5. Is stored in the storage space 23.

From this collapsed state, the drive gear 3b rotatably provided on a part of the peripheral wall of the fixed frame 3 is rotated by the zoom drive system, and the gear portion 13b meshing with the drive gear 3b rotates around the optical axis. When the rotary frame 4 integrated with the gear portion 13b is rotated as a result, the rotary frame 4 is rotated.
Is rotated forward around the optical axis by a helicoid screw and is fed forward. At this time, the float key 22 retracted to the camera body 2 side is not moved forward together with the rotary frame 4, and while the rotation is restricted by the straight guide groove 3a of the fixed frame 3 for a while, The rotation of the second group frame is restricted so that the front-rear direction is maintained at the same position.

By rotating the rotary frame 4,
The three second groups of cam followers 17 of the second group frame 10 whose rotation is restricted by the float key 22 are moved along the second group cam grooves 18 of the rotating frame 4, and at the same time, the rotation of the second group frame 10 is restricted. 6 cam followers 16 of straight frame 5
Are moved along the six cam grooves 15 of the rotary frame 4. In this way, the second group frame 10 and the rectilinear frame 5 are relatively moved in the front optical axis direction of the rotary frame 4 while the rotation is restricted.

Then, the rotary frame 4 relatively moves in the front optical axis direction while further rotating, and the second group frame 10 and the rectilinear frame 5 move while the rotation is restricted in the front optical axis direction. When the float key guide projection 21 of the frame 10 reaches the tip of the guide groove 22d of the float key 22, thereafter, the float key guide projection 21 of the second group frame 10 pulls and moves the float key 22 forward, The tele state of FIG. 1 is reached. At this time, the protrusion 22b of the float key is moved forward along the straight guide groove 3a of the fixed frame 3.

Further, from the telephoto state shown in FIG. 1, when the rotary frame 4 is rotated in the opposite direction by the zoom drive system, the rotary frame 4 is retracted backward while rotating around the optical axis by a helicoid screw. Will be done. By this rotation, the second group frame 10 and the rectilinear frame 5 whose rotation is restricted are also stored rearward along the respective cams and cam grooves. At this time, even if the second-group frame 10 and the rectilinear frame 5 are stored rearward, the float key 22 of the second-group frame 10 is restrained to the optical axis rearward with respect to the float key 22 of the second-group frame 10. The amount of receding in the optical axis direction is indefinite.

At least the rear end surface of the rotary frame 4 is
By contacting the base end portion 22a of the float key 22 while retreating along the helicoid screw, the rotating frame 4 reliably rotates the float key 22 rearward while rotating.

As described above, according to the present embodiment, the float key 22 is arranged without being integrated with a specific frame as in the conventional case. Necessary screws, other parts, etc. are unnecessary, and the structure is simple, but the number of parts is small, the number of assembling steps can be reduced, and it is possible to reduce the size and weight and the cost.

[0030]

As described above, according to the present invention, the rotation of a specific frame can be reliably regulated with a simple structure.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view taken along an optical axis in a telephoto state of a lens barrel as a photographing lens provided in a camera.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an exploded perspective view of a lens barrel.

4 is a longitudinal sectional view along the optical axis of the lens barrel of FIG. 1 in a collapsed state.

[Explanation of symbols]

1 ... Lens barrel 3 ... Fixed frame (first frame) 4 ... Rotating frame (third frame) 10 …… 2 group frame (second frame) 21 ...... Float key guide projection 22 ...... Float key (key member) 22a ... the base end 22b ... projection 22c: Straight arm 22d ... Guide groove

Claims (2)

[Claims] 1. A first frame, a second frame that is relatively movable in the optical axis direction with respect to the first frame, and is rotated relative to the first frame and relatively moved in the optical axis direction with respect to the first frame. Relative rotation between the third frame for moving the second frame in the optical axis direction and the first frame is restricted, and the optical axis direction with respect to the first frame and the third frame. And a key member for restricting relative rotation of the second frame, which is arranged so as to be relatively movable with respect to the lens barrel. 2. The lens barrel according to claim 1, wherein the key member is linearly moved by the second frame.