JPH05249360A - Zoom lens barrel - Google Patents

Abstract

PURPOSE:To shorten an entire length even though a zoom magnification is large, and to make a zoom lens barrel compact by providing a lens holding frame advancing and retreating in an optical axis direction for a second cam frame by the cooperation of the second cam frame and a fixed frame in the optical axis direction. CONSTITUTION:The lens supporting frame 41 holding a first lens group L1 is fixed to a first lens barrel 40, the outside surface side of the key part of a floating key 80 is fitted into a guiding groove in the optical axis direction, so that the lens barrel 40 is controlled to move only in the optical axis direction. The lens supporting frame 51 holding a second lens group L2 is fixed to a second lens barrel 50, the inside surface side of the key part of the floating key 80 fitting in the guiding groove is fitted in a notched part for guiding, so that the lens barrel 50 is controlled to move only in the optical axis direction. Furthermore, the lens supporting frame 61 holding a third lens group L3 is fixed to a third lens barrel 60, the key part of the floating key 80 is fitted in the notched part for guiding, so that the lens barrel 60 is controlled to move only in the optical axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a zoom lens barrel,
More specifically, the present invention relates to the configuration of a zoom lens barrel that moves a lens holding frame forward and backward in the optical axis direction by rotating a cam frame around a fixed frame.

[0002]

2. Description of the Related Art Conventionally, various cameras having a zoom lens have been proposed and sold, and many technical means for the zoom lens section have been proposed.

An example of the technical means relating to the conventional zoom lens portion will be described by taking the technical means disclosed in Japanese Patent Laid-Open No. 2-248909 by the present applicant as an example.

This technical means is an improvement of a lens barrel having a structure of a cam ring-fixed frame-lens support frame, which constitutes a frame of a zoom lens barrel which has been known before. This has the effect of shortening the overall length of the zoom lens barrel.

The structure of this technical means will be described with reference to FIG.

The first cam ring 102 fitted to the outer diameter of the fixed frame 101 is provided with a rectilinear groove 102a, and the interlocking cam 108 is integrally attached to the outer diameter thereof.
A second cam ring 103 is fitted on the inner diameter of the fixed frame 101, and the moving frame 10 is fitted on the inner diameter of the second cam ring 103.
4 is fitted. In addition, the inner diameter of the moving frame 104 includes the second lens group supporting frame 106 and the third lens group supporting frame 10.
7 is fitted and the moving frame 104 has a first
The first group lens frame 105 holding the group lens 116 is fixed. Further, the second group lens support frame 106 includes
A second group lens frame 117 holding the second group lens 118 is attached via a shutter unit 119. Further, the third group lens support frame 107 has a third
The third group lens support frame 107 holding the group lens 120 is fixed.

On the other hand, the second group roller 114, which is planted in the second group lens support frame 106, has the moving frame 104.
And the second cam ring 103 described above.
And the second group lens cam groove 103b provided in the above. The third group roller 115 embedded in the third group lens support frame 107 is fitted in both the straight groove 104b provided in the moving frame 104 and the straight groove 103c provided in the second cam ring 103. It fits.

Further, the first group roller 113 embedded in the moving frame 104 is the first group roller provided on the second cam ring 103.
The group lens cam groove 103a and the 101d rectilinear groove provided on the fixed frame 101 are fitted together. Also, the second
The roller 112 embedded in the cam ring 103 is the fixed frame 10
1 is provided with the lead groove 101c and the first cam ring 10
They are fitted together in the straight groove 102a provided in No. 2.

The operation of the zoom lens barrel thus constructed is as follows.

When the zoom motor 111 provided in the reduction gear train 110 is activated and the interlocking gear 108a is driven,
The first cam ring 102 rotates around the optical axis. This allows
The second cam ring 103 moves in the optical axis direction while rotating around the optical axis due to the relationship between the straight advance groove 102a, the lead groove 101c, and the roller 112.

With the operation of the second cam ring 103,
The second cam ring 103 moves in the optical axis direction due to the relationship between the straight-moving groove 101d, the first group lens cam groove 103a, and the first group roller 113. Thereby, the second group lens cam groove 10
3b, the rectilinear groove 104a, the second group roller 114, and the third group lens cam groove 103c, the rectilinear groove 104b, and the third group roller 115, the second group lens support frame 106 and the third group lens support frame 107 are also included. It will move in the optical axis direction.

Here, the moving amounts of the first lens group 116, the second lens group 118, and the third lens group 120 are PL respectively.
1, PL2, PL3, the length of the rectilinear groove 102a in the optical axis direction is PLA, the first group lens cam groove 103a, the second group
Group lens cam groove 103b, third group lens cam groove 103c
Let PLB, PLC, and PLD be the lengths in the optical axis direction of: PL1 = PLA + PLB PL2 = PLA + PLC PL3 = PLA + PLD.

Here, the minimum required length of the first cam ring 102 is X3, the minimum required length of the second cam ring 103 is X5, and the minimum length from the roller 112 to the first group roller 113 is PLM. , The second group roller 114 to the third group roller 11
If the minimum length up to 5 is PLN, then X3> PLA + PLM X5> MAX (PLB, PLC, PLD) + PLN.

Therefore, the length PL is PL> MAX (X3, X5) when the total lens length is shortened to the maximum.

Therefore, when the length PL is the shortest, PLA = 1/2 (MAX (PL1, PL2, PL3)). Here, if PL1 is the longest, PLA = 1/2 × PL1 and PL> 1/2 × PL1 + PLM (or PLN).

That is, the length PL at which the total length of the lens frame is maximally shortened is larger than 1/2 of the maximum movement amount of the lens unit having the largest movement amount of the zoom lens.

When PLA is 1 / 2PL1, PLB = PL1 and the first group lens cam groove 103a is provided substantially over the entire length of the second cam ring 103. In addition, the first group lens cam groove 103a is exposed. That is, such a lens barrel is impossible.

Therefore, PLA must be much larger than 1/2 × PL1. Therefore, PL >> 1/2 × PL1 + PLM (or PLN).

By the way, the zoom lens barrel having such a structure can shorten the entire length of the zoom lens barrel as compared with the zoom lens barrel known before that, but the amount which can be miniaturized is small. It wasn't that big. Therefore, in the recent situation in which the zoom magnification tends to increase, the amount of movement of the zoom lens inevitably increases, which increases the overall length of the lens barrel.

As a technical means for solving such a problem, Japanese Utility Model Application Laid-Open No. 2-10515 proposes a zoom lens barrel having a high magnification even though the entire length of the lens barrel is short.

This lens barrel has a cam ring having an inner helicoid member fixed to an outer helicoid member fixed to a fixed frame, and is rotatable about the optical axis with respect to the cam ring. A guide ring integrated in the optical axis direction (integrated around the optical axis with respect to the fixed frame) is provided. Further, a cam groove for driving the lens and a rectilinear groove are respectively provided in the inner diameter portions of the cam ring and the guide ring,
A lens group holding frame having a cam follower fitted into each of the cam ring and the guide ring is fitted into the inner diameter of the guide ring.

In this state, when the inner helicoid member is rotated around the optical axis, the cam ring integrated with the inner helicoid member moves in the optical axis direction while rotating. By this operation, the guide ring moves back and forth in the optical axis direction by the same amount as the cam ring. Further, by this operation, the guide ring is rotated around the optical axis with respect to the cam ring (not rotated with respect to the fixed frame).

Therefore, each lens group holding frame can move in the optical axis direction by the amount of movement of the cam ring and the length of the cam groove of the cam ring in the optical axis direction. Therefore, the length of the cam ring and the length of the fixed frame can be made shorter than the moving amount of each lens group holding frame. That is, it is possible to obtain a movement amount larger than the length of the cam ring and the fixed frame in the optical axis direction.

[0024]

However, since the guide ring can be arranged only on the outer diameter of the lens group holding frame, the outer diameter of the lens barrel becomes large as a result. Further, the movement amount of the cam ring with respect to the fixed frame is limited by the length of the inner helicoid member in the optical axis direction. Therefore, the length of the cam groove for each lens group holding frame that must be provided in the cam ring itself. Inevitably becomes longer. Therefore, the cam ring itself also becomes long, which also extends the overall length of the lens barrel. Therefore, it is difficult to supply a compact camera with a large zoom magnification, but the current situation is.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a compact zoom lens barrel having a short overall length even if the zoom magnification is large.

[0026]

A first zoom lens barrel according to the present invention has a fixed frame fixed to a camera body and an outer periphery of the fixed frame rotatably arranged around an optical axis. A first cam frame and an inner circumference of the fixed frame, and by the rotation of the first cam frame with respect to the fixed frame,
A second cam frame that advances and retracts with respect to the fixed frame in the optical axis direction, and is supported integrally with the second cam frame in the optical axis direction and rotatably around the optical axis, and in the optical axis direction. A movable member having a fork portion extending to the inner side of the second cam frame, cam-coupled to the second cam frame, and coupled to the fork portion of the movable member at the inner peripheral surface. By doing so, a lens that is integrated with the movable member around the optical axis and that moves forward and backward in the optical axis direction with respect to the second cam frame by the cooperation of the second cam frame and the fixed frame in the optical axis direction. And a holding frame.

The second zoom lens barrel according to the present invention comprises:
A fixed frame fixed to the camera body, and a first cam frame rotatably arranged around the optical axis around the fixed frame,
A second cam that is arranged on the inner circumference of the fixed frame and that rotates around the optical axis with respect to the fixed frame by the rotation of the first cam frame with respect to the fixed frame and that moves forward and backward in the optical axis direction. A frame, a movable member that is supported integrally with the second cam frame in the optical axis direction and is rotatable about the optical axis, and has a fork portion extending in the optical axis direction; Is arranged on the inner periphery of the cam frame, is cam-coupled to the second cam frame, and is also integral with the movable member around the optical axis by being coupled to the fork portion of the movable member on the inner peripheral surface, A lens holding frame is provided that advances and retreats in the optical axis direction with respect to the second cam frame by relative rotation of the second cam frame and the fixed frame.

[0028]

The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is a cross-sectional view of an essential part of a camera having a lens barrel showing an embodiment of the present invention.
[FIG. 4] is an exploded perspective view showing respective members constituting the lens barrel by extending them in the optical axis direction.

In this embodiment, the present invention is applied to a zoom lens barrel, which includes a fixed barrel 10 integrally attached to the camera body 1. The upper half of FIG. 1 shows the wide state where the zoom lens is moved to the wide position, and the lower half shows the tele state where the zoom lens is moved to the tele position.

The camera having this lens barrel is composed of a front cover 2 for covering the front part of the camera body 1, a rear cover 3 for covering the rear part thereof, and a back cover 4 as a main part. The back cover 4 attached to the rear cover 3 by a hinge (not shown) so as to be freely opened and closed,
The light-blocking elastic member 5 is adapted to be light-tightly closed.

The zoom lens barrel is composed of the fixed barrel 10
Is rotatably fitted to the outer peripheral surface of the drive barrel 20 and is fitted to the inner peripheral surface of the fixed barrel 10 and is driven by the drive barrel 20. A cam barrel 30 that moves back and forth in the optical axis direction while rotating, and a first lens barrel 40 and a second lens barrel 50 that are sequentially arranged in the cam barrel 30 from the front and that move back and forth in the optical axis direction. The third lens barrel 60 and the cam barrel 30 are arranged in the same manner. The key receiving member 34 prevents movement in the optical axis direction, and the fixed barrel 10 prevents rotation around the optical axis. , The first lens barrel 40, the second lens barrel 50, the third
A float key 80 for restricting rotation of the lens barrel 60 around the optical axis, and a barrier driver 53 provided in the front side of the first lens barrel 40 and supported in the second lens barrel 50 (see FIG. 1). Barrier unit 70 (see FIG. 1) in which the barrier 71 is opened and closed by the reference lens), and the second lens barrel 5 described above.
The shutter blades 54 (see FIG. 1) that are opened and closed by the shutter unit 52 (see FIG. 1) supported in 0, and are stretched between the second lens barrel 50 and the third lens barrel 60 will be described later. The elastic member 90 is formed of a coil spring for absorbing looseness of fitting of the drive rollers 50a and 60a into the cam groove holes 30b and 30c, and a flare diaphragm 100 attached to the rear portion of the float key 80. ..

The drive cylinder 20 is provided with a drive gear 21, a guide rib 22, and an interlocking cam 23, which are formed in a partially arcuate shape on the outer peripheral surface thereof, in this order from the front. The drive gear 21 receives a driving force from a zoom drive unit (not shown), guides the drive barrel 20 by the guide ribs 22 and rotates around the optical axis O in the counterclockwise direction A or the clockwise direction B (FIG. 2).
Refer to)). The interlocking cam 23 also serves to zoom the lens of the finder optical system (not shown). The drive barrel 20 is provided with guide long groove holes 20a in the optical axis direction at three circumferentially divided positions, and a rear end of the drive barrel 20 is provided with a data unit (not shown) described later. Notch 2 for passing the date-imprinting light beam
0b is formed. An encoder 250 for detecting the amount of rotation of the drive barrel 20 is provided at the rear edge of the drive barrel 20.

The fixed barrel 10 is provided with lead-shaped cam groove holes 10a for moving the cam barrel 30 back and forth in the optical axis direction while rotating the cam barrel 30 at three equal positions on its peripheral surface. A straight guide groove 10b into which a guide projection 80a of a float key 80, which will be described later, is fitted, is formed at three circumferentially divided positions on the inner peripheral surface. Then, as shown in FIG. 2, the rear end portion of the fixed barrel 10 facing the film surface side is adjacent to the end of the cam groove hole 10a located above the camera among the cam groove holes 10a. A rectangular through hole 10c that is long in the optical axis direction is provided. This through hole 1
Reference numeral 0c is formed so that the cutout portion 20b of the drive cylinder 20 is overlapped at the time of photographing, and allows a date imprinting light flux from a data unit (not shown), which is a data imprinting means, to pass toward the film surface. Play a role. A stop projection 10d for restricting the rotation of the drive cylinder 20 is provided on the outer peripheral surface of the through hole 10c on the side opposite to the end of the cam groove hole 10a. The mounting arm portion 10e formed on the rear end edge of the fixed barrel 10 so as to project in the radial direction is a mounting portion to the camera body 1.

The cam barrel 30 fitted to the inner peripheral surface of the fixed barrel 10 has the first lens barrel 40 on the inner peripheral surface thereof.
Groove 30a for moving the optical axis in the optical axis direction
Are formed in three equal positions, and similarly, a cam groove 30b for zooming the second lens barrel 50 in the optical axis direction and a zoom groove 30b for moving the third lens barrel 60 in the optical axis direction. The cam grooves 30c are formed at three equally divided positions on the inner peripheral surface. The state of each of the cam grooves 30a to 30c is shown in detail in FIG. In FIG. 5, the inner peripheral surface of the cam cylinder 30 is partially cut away and shown in plan view. Further, in the figure, reference numeral F2 indicates that the third lens barrel 60 is a float key 80 when each lens group is in the retracted state from the wide state (hereinafter, referred to as the W state).
The distance F is shown in FIG.
Indicates the distance that the third lens barrel 60 moves with respect to the float key 80 when each lens group moves from the W state to the tele state (hereinafter referred to as the T state).

Returning to FIG. 2 again, the zoom drive roller 32 is fixed by screws 33 to the outer peripheral surface of the rear end edge of the cam barrel 30 at three equal positions. The roller 32 passes through the cam groove hole 10a of the fixed barrel 10 and the drive barrel 2
No. 0 long slot for guide 20a is fitted. Therefore, when the drive barrel 20 rotates about the optical axis O, the zoom drive roller 32 also rotates due to the guide long groove hole 20a, so that the cam barrel 30 rotates with the cam groove hole 10a. Move back and forth in the direction.

The first lens barrel 40 has a lens support frame 41 holding a first lens unit L1 (see FIG. 1) fixed to the front portion inside thereof, and also has an inner peripheral surface 3
A relatively wide guide groove 40b in the optical axis direction is bored at equal positions, and the outer surface side of a key portion 80b of a float key 80, which will be described later, is fitted into the guide groove 40b, so that the lens barrel 40 is exposed to light. It is restricted to move only in the axial direction.
Further, a drive roller 40a is fixedly planted on the outer peripheral surface of the rear end portion of the lens barrel 40 at three equally divided positions, and the drive roller 40a is fitted into the cam groove 30a of the cam barrel 30.

The second lens barrel 50 has a lens support frame 5 having a second lens unit L2 (see FIG. 1) held therein.
1 is fixed, and a comparatively wide circumferential guide notch 50e is provided at three equally spaced positions on the outer peripheral surface of the guide groove 40e.
The inner surface side of the key portion 80b of the float key 80 fitted in b is fitted, and the lens barrel 50 is restricted so as to move only in the optical axis direction. Therefore, the float key 80
The key portion 80b is sandwiched between the guide groove 40b and the guide cutout portion 50e. Further, in the rear part between the guide notches 50e on the outer peripheral surface,
The drive roller 50a is fixed. Therefore, the drive rollers 50a are fixedly planted in three positions on the outer peripheral surface of the rear end of the lens barrel 50, respectively.
a is fitted in each of the cam grooves 30b of the cam barrel 30.

The second lens barrel 50 is provided with the shutter unit 52 and the shutter blades 54, as described above, so that the second lens barrel 50 can move back and forth integrally with the second lens barrel 50.

The third lens barrel 60 has a lens support frame 6 having a third lens unit L3 (see FIG. 1) held therein.
1 is fixed, and a relatively wide circumferential guide notch 60b is provided at three equally spaced positions on the outer peripheral surface thereof. The guide notch 60b is provided with the guide groove 40b. The key portion 80b of the float key 80 interposed between the guide notch portion 50e and the guide notch portion 50e is fitted into the lens barrel 6 and
It is regulated that 0 moves only in the optical axis direction. In addition, the guide notch 6 on the outer peripheral surface of the lens barrel 60.
A drive roller 60a is fixedly planted between 0b. Therefore, this drive roller 60a is
No. 0 is fixedly planted in three equally divided positions on the outer peripheral surface of each of the drive rollers 60a.
Has been inserted into each.

The cam groove 3 is provided between the front end face of the third lens barrel 60 and the rear end face of the second lens barrel 50.
The elastic member 90 formed of a coil spring is stretched to absorb the looseness of the fitting between the driving roller 50a fitted into the cam groove hole 30c and the driving roller 60a fitted into the cam groove hole 30c.

The float key 80 has an annular base portion 8 whose front portion is located on the inner periphery of the rear end portion of the cam barrel 30.
0c and 3 extending forward from the trisection position on the front
The key portions 80b of the book, the rectangular fitting holes 80e formed in the key portions 80b near the annular base portion 80c and elongated in the optical axis direction, and the annular base portion 80c.
Of the fixed cylinder 1 projectingly provided at three equal positions on the outer peripheral surface of the
Guide protrusion 80a that fits into the straight guide groove 10b of 0
It is formed by and. The float key 80 is provided with a key receiving member 34 fixed by the screw 33 at the same time when the zoom driving roller 32 is fixed by the screw 33 at three positions on the outer peripheral surface of the rear end edge of the cam cylinder 30. The rear end face of the annular base 80c is received by the optical axis O so that it moves along with the cam barrel 30 in the optical axis direction, but the guide projection 80a fits in the straight guide groove 10b of the fixed barrel 10 so that the optical axis O Rotation around is blocked.
The three key portions 80b extending forward are formed by the guide notch 60b of the third lens barrel 60, the guide notch 50e of the second lens barrel 50, and the guide of the first lens barrel 40. It is inserted in the groove 40b.

The flare stop 100 (see FIG. 3) has an annular peripheral wall part 100b which is formed on the outer periphery of a thin disk having a flare stop opening 100c formed in the center thereof and which faces forward.
With the elastic mounting piece 100a extending forward from the trisection position on the front surface of the annular peripheral wall portion 100b, and the locking claw 100d formed on the outer peripheral surface of the tip end of the mounting piece 100a. The third lens barrel 60 is configured from the rear of the float key 80 along the inner peripheral wall surface thereof.
The locking claw 100d of the mounting piece 100a is fitted so as not to interfere with the rectangular fitting hole 80e of the float key 80.
It is attached to the rear portion of the float key 80 so as to be movable in the optical axis direction by the length of the fitting hole 80e.

As shown in FIG. 1, an O-ring 11 for maintaining light tightness and liquid tightness is arranged between the inner peripheral surface of the front end of the front cover 2 and the outer peripheral surface of the front end of the fixed barrel 10. And the inner peripheral surface of the fixed cylinder 10 near the front end and the cam cylinder 3
No. 0 outer peripheral surface and the front end surface of the cam barrel 30 and the first
Elastic rings 12 and 31 for maintaining light-tightness and liquid-tightness are also arranged between the outer peripheral surface of the lens barrel 40 and the outer peripheral surface.

Next, the operation of the zoom lens barrel constructed as described above will be described with reference to FIGS. FIG. 4 shows each lens group in the zoom lens barrel from the retracted state to the telephoto state (hereinafter referred to as the T state).
It is a diagram showing the movement up to.

First, an output gear (not shown) of the zoom motor unit meshes with the drive gear 21 to move the drive cylinder 20 to the A position.
Direction or B direction (see FIG. 2). At this time, if it is assumed that the cam barrel 30 rotates in the A direction from the retracted state, the cam barrel 30 rotates in the A direction due to the relationship between the long guide slot 20a and the cam slot 10a, and the optical axis C direction (see FIG. 2).
Move to. At this time, the float key 80, which is only rotatable in the cam barrel 30 and is integrated in the optical axis direction, moves straight in the optical axis C direction without rotating due to the relationship between the straight guide groove 10b and the guide projection 80a. To do. Further, as described above, since the first lens barrel 40, the second lens barrel 50, and the third lens barrel 60 do not rotate with respect to the float key 80, the first lens barrel 40, the second lens barrel 50, and the third lens barrel 50. The lens barrel 60 also does not rotate but only moves straight.

Here, as described above, the cam groove in the cam barrel 30 is constituted by the cam groove 30a for the first lens group, the cam groove 30b for the second lens group, and the cam groove 30c for the third lens group. The cam grooves 30a, 30
The maximum movement amounts LL1, LL2, LL3 of the respective lens groups combined by b, 30c and the cam groove hole 10a are shown in FIG.
Is shown in. Maximum movement amount LL1, LL
Reference numerals 2 and LL3 represent the maximum movement amounts of the first lens unit L1, the second lens unit L2, and the third lens unit L3, respectively.
Further, in the figure, reference numerals L1, L2a, L2b and L3 all indicate the movement loci of the above lens groups, L1 is the locus of the first lens group, and L2a and L2b are infinity and infinity in the second lens group. The locus at large time, L3, shows the locus of the third lens group. In the figure, reference numeral 1b indicates the film surface, and reference numeral LLM indicates the minimum length from the lens support frame 41 to the drive roller 60a.

Considering the float key 80 as a reference, the cam barrel 30 rotates only.
The rotation of the respective lens groups moves from the retracted state to the T state as shown in FIG.

When the output gear of the zoom motor unit rotates in the opposite direction, the drive barrel 20 rotates in the B direction (see FIG. 2), and as a result, the respective lens groups are moved from the T state as shown in FIG. Move in the collapsed state.

The cutout portion 20 provided in the drive cylinder 20
b is engaged with a stop projection 10d provided on the fixed barrel 10, and when the drive barrel 20 goes too far in the retracting direction from the retracted state, and when it goes far beyond the T state toward the telephoto side, It is designed to regulate rotation.

As shown in FIG. 4, the maximum amount of movement of each lens group is LL1, LL2, LL3, and the minimum length from the lens support frame 41 to the drive roller 60a is L.
Assuming LM, the total length of the cam barrel 30 can be set to about LL1 / 2 + LLM, and at that time, the total length of the fixed barrel 10 can be set to about LL1 / 2.

Therefore, the zoom lens barrel of the first embodiment can have a length of about LL1 / 2 + LMM at the minimum.

Here, the conventional zoom lens barrel is first described below.
If the structure is the same as that of the embodiment, the minimum length of the lens barrel of the conventional example is larger than LL1 + LLM, so obviously the first embodiment can provide a zoom lens barrel having a shorter total length.

FIG. 6 is a sectional view of a zoom lens barrel showing a second embodiment of the present invention.

The basic structure of the second embodiment is the same as that of the first embodiment, and the shapes of the second lens barrel 50 and the float key 80 in the first embodiment are partially changed. Only the differences will be described here because only the differences are present.

FIG. 7 is an exploded perspective view showing each member constituting the zoom lens barrel in the present embodiment extended in the optical axis direction, except for the second lens barrel 150 and the float key 180. The configuration is similar to that of the first embodiment.

The second lens barrel 150 is internally provided with
The lens support frame 51 holding the second lens unit L2 (see FIG. 6) is fixed, and a rear portion having a front end wall 50c and having a relatively wide width in the circumferential direction is opened at three equal positions on the outer peripheral surface thereof. Further, a guide concave portion 50b in the optical axis direction is provided, and the inner surface side of the key portion 180b of the float key 180 fitted in the guide groove 40b (see FIG. 6) is fitted in the guide concave portion 50b, and the lens barrel 150 Are regulated so that they move only in the optical axis direction. Therefore, the key portion 180b of the float key 180 is sandwiched between the guide groove 40b and the guide recess 50b. A drive roller 50a is fixedly planted in the rear portion of the outer peripheral surface between the guide recesses 50b. Therefore, the drive rollers 50a are fixedly planted in three equal positions on the outer peripheral surface of the rear end portion of the lens barrel 150, and the drive rollers 50a are fitted in the cam grooves 30b (see FIG. 6) of the cam barrel 30. Each is fitted.

The second lens barrel 150 is provided with a shutter unit 52 and shutter blades 54 as in the first embodiment, so that the second lens barrel 150 can be moved back and forth integrally. Is becoming

Since the operation of the second embodiment having such a configuration is the same as that of the first embodiment, its explanation is omitted here.

The effect of the second embodiment is that, in addition to the effect of the first embodiment that the total length of the lens barrel is shortened, external light entering the lens barrel as shown in FIG. Can be prevented by the front end wall 50c provided on the second lens barrel 150, and light can be prevented from leaking to the film surface.

Next, a third embodiment of the present invention will be described.

FIG. 9 and FIG. 10 are exploded perspective views showing respective members constituting the zoom lens barrel which is the third embodiment of the present invention, being extended in the optical axis direction.

In the zoom lens barrel of the third embodiment, the drive barrel 20 is fitted around the optical axis of the fixed barrel 10 fixed to the camera body (not shown) by the mounting arm 10e. ing.

A cam cylinder 30 is provided on the inner circumference of the fixed cylinder 10.
Is fitted. Here, the fixed barrel 10 is provided with a first straight cam groove 10a 'extending in the optical axis direction, and the drive barrel 20 is provided with a third cam groove 20a' in an oblique direction. Then, the zoom drive roller 32 fixed to the outer periphery of the cam barrel 30 is provided with the first straight cam groove 10.
a'and the third cam groove 20a 'are both fitted together.

The first lens barrel 40 and the second lens barrel 5 each holding a lens group (not shown) inside the cam barrel 30.
0 and the third lens barrel 60 are fitted. A float key 80, which is a movable rectilinear member, is provided at the rear end of the cam barrel 30, and the float key 80 is fixed to the cam barrel 30 together with the zoom drive roller 32 with a screw 33. By the key receiving member 34,
It is immovable in the optical axis direction with respect to 0 and is movable around the optical axis.

The drive roller 4 is attached to the first lens barrel 40.
0a is provided, and the drive roller 40a is fitted in the fourth cam groove 30a provided in the inner diameter portion of the cam barrel 30. Further, a guide groove 40b is provided in the inner diameter portion of the first lens barrel 40, and the key portion 80 extending in the optical axis direction from the annular base portion 80c of the float key 80.
engaged with b. That is, the first lens barrel 40 is immovable with respect to the float key 80 around the optical axis.

Similarly, the drive roller 50a protruding at the center of the step provided on the outer periphery of the second lens barrel 50 is connected to the cam barrel 30.
Since it fits in the fifth cam groove 30b provided in the inner diameter portion of the and also engages with the key portion 80b in the guide cutout portion 50e between the step portions, the second lens barrel 50 and the float key 80 are It is fixed around the optical axis.

In addition, the third lens barrel 60 and the float key 8
The relationship with 0 is also configured similarly, and the third lens barrel 60
Is fixed to the float key 80 around the optical axis.

The coil spring 90 is used for the second lens barrel 5
0 and the third lens barrel 60 are stretched so that the play of the second lens barrel 50 and the third lens barrel 60 with respect to the cam barrel 30 is extremely small.

The guide projection 80a provided on the outer peripheral portion of the annular base portion 80c is fitted into the second cam groove 10b 'which is an oblique groove provided on the inner diameter portion of the fixed barrel 10.

The operation of the third embodiment thus constructed will be described.

First, a zoom drive unit (not shown) is activated, and the driving force is transmitted to the drive gear 21 provided on the outer periphery of the drive cylinder 20 with which the output gear of the unit is meshed. Now, when the drive cylinder 20 rotates in the direction of arrow A in the drawing, the third cam groove 20a 'and the first straight cam groove 10 are formed.
a ', the cam cylinder 3 depending on the relationship with the zoom drive roller 32
0 moves to the left of the optical axis in the figure. At this time, the float key 80 rotatably attached to the cam barrel 30 has the guide projection 80a and the second cam groove 10b '.
Therefore, the same amount as the cam barrel 30 moves to the left in the optical axis in the figure, and the optical axis rotates about the optical axis by the amount regulated by the first rectilinear cam groove 10a '.

That is, the float key 80 rotates relative to the cam barrel 30 by a predetermined amount. The rotation of the predetermined amount causes the first lens barrel 40, the second lens barrel 50, and the third lens barrel 60 to rotate with respect to the cam barrel 30 by the same amount as the float key 80. Therefore,
Due to the relationship among the fourth cam groove 30a, the fifth cam groove 30b, the sixth cam groove 30c and the drive rollers 40a, 50a, 60a, the first lens barrel 40, the second lens barrel 50, the The three-lens tube 60 moves in the optical axis direction by an appropriate amount.

That is, when the drive barrel 20 rotates about the optical axis, the cam barrel 30 moves straight in the optical axis direction, and the first lens barrel 40, the second lens barrel 50, and the third lens barrel 60.
While moving around the optical axis, it moves in the optical axis direction to provide a predetermined zoom state. It should be noted that when a zoom drive unit (not shown) is rotated in the opposite direction to the above, and the drive barrel 20 is rotated in the direction of the arrow B in the drawing, the movement is performed in the opposite direction to the above-described operation.

Next, a fourth embodiment of the present invention will be described.

FIG. 11 and FIG. 12 are exploded perspective views showing the respective members constituting the zoom lens barrel which is the fourth embodiment of the present invention, extended in the optical axis direction.

In the third embodiment described above, the cam barrel moves straight in the optical axis direction with respect to the fixed barrel, but in the fourth embodiment, the cam barrel moves while rotating around the optical axis. ..

In the zoom lens barrel of the fourth embodiment, a drive barrel 20 is rotatably fitted around the optical axis around the outer periphery of a fixed barrel 10 fixed to a camera body (not shown) by a mounting arm 10e. ing.

A cam barrel 30 is provided on the inner circumference of the fixed barrel 10.
Is fitted. Here, the fixed barrel 10 is provided with a first straight cam groove 10f extending in the optical axis direction, and the drive barrel 20 is provided with a third cam groove 20c in an oblique direction. The zoom drive roller 32 fixed to the outer circumference of the cam barrel 30 is configured to be fitted into both the first straight cam groove 10f and the third cam groove 20c.

The first lens barrel 40 and the second lens barrel 5 each holding a lens group (not shown) inside the cam barrel 30.
0 and the third lens barrel 60 are fitted. A float key 80, which is a movable rectilinear member, is provided at the rear end of the cam barrel 30, and the float key 80 is fixed to the cam barrel 30 together with the zoom drive roller 32 with a screw 33. By the key receiving member 34,
It is immovable in the optical axis direction with respect to 0 and is movable around the optical axis.

The drive roller 4 is attached to the first lens barrel 40.
0a is provided, and the drive roller 40a is fitted in the fourth cam groove 30d provided in the inner diameter portion of the cam barrel 30. A guide groove 40b is provided in the inner diameter portion of the first lens barrel 40, and is engaged with a key portion 80b integrally extending from the annular base portion 80c of the float key 80 in the optical axis direction. That is, the first lens barrel 40 is immovable with respect to the float key 80 around the optical axis.

Similarly, the drive roller 50 a protruding at the center of the step provided on the outer periphery of the second lens barrel 50 is connected to the cam barrel 30.
Since it fits in the fifth cam groove 30b provided in the inner diameter portion of the and also engages with the key portion 80b in the guide cutout portion 50e between the step portions, the second lens barrel 50 and the float key 80 are It is fixed around the optical axis.

Further, the third lens barrel 60 and the float key 8
The relationship with 0 is also configured similarly, and the third lens barrel 60
Is fixed to the float key 80 around the optical axis.

The coil spring 90 is used for the second lens barrel 5
0 and the third lens barrel 60 are stretched so that the play of the second lens barrel 50 and the third lens barrel 60 with respect to the cam barrel 30 is extremely small.

Further, the guide projection 80d provided on the outer peripheral portion of the annular base portion 80c is fitted into the second cam groove 10g which is an oblique groove provided on the inner diameter portion of the fixed barrel 10.

The operation of the third embodiment thus constructed will be described.

First, a zoom drive unit (not shown) is activated, and the drive force is transmitted to the drive gear 21 provided on the outer periphery of the drive cylinder 20 with which the output gear of the unit is meshed. Now, when the drive cylinder 20 is rotated in the direction of arrow A in the drawing, the third cam groove 20c, the first straight cam groove 10f,
Due to the relationship with the zoom drive roller 32, the cam barrel 30 moves while rotating in the left direction of the optical axis in the drawing. At this time, the float key 80 rotatably attached to the cam barrel 30 has the guide protrusion 80d and the second cam groove 10
Due to the relationship with g, the same amount as that of the cam barrel 30 moves to the left in the optical axis in the figure, and it rotates about the optical axis by the amount regulated by the second cam groove 10g.

That is, the float key 80 rotates relative to the cam barrel 30 by a predetermined amount. The relative rotation of the predetermined amount causes the first lens barrel 40, the second lens barrel 50, and the third lens barrel 60 to rotate relative to the cam barrel 30 by the same amount as the float key 80. Therefore, the relationship between the fourth cam groove 30d, the fifth cam groove 30e, the sixth cam groove 30f, and the drive rollers 40a, 50a, 60a causes the first lens barrel 40 and the second lens barrel 50 with respect to the cam barrel 30. The third lens barrel 60 moves in the optical axis direction by an appropriate amount.

That is, when the drive barrel 20 rotates around the optical axis, the cam barrel 30 moves while rotating in the optical axis direction, and the first lens barrel 40, the second lens barrel 50, and the third lens barrel. The 60 moves in the optical axis direction while rotating around the optical axis to provide a predetermined zoom state. It should be noted that when a zoom drive unit (not shown) is rotated in the opposite direction to the above, and the drive barrel 20 is rotated in the direction of the arrow B in the drawing, the movement is performed in the opposite direction to the above-described operation.

In this embodiment and the third embodiment,
Although the shape of the guide projection provided on the annular base portion 80c of the float key 80 is different, it is obvious that the same effect can be obtained by using either one.

Further, in both the third and fourth embodiments, the drive cylinder 20 provided on the outer periphery of the fixed cylinder 10 is rotated to move the cam cylinder 30 in the optical axis direction. The present invention is not limited to this, and it is obvious that any structure may be used as long as the cam cylinder 30 can move with respect to the fixed cylinder 10. Therefore, the drive cylinder 20 is not an essential component in this embodiment.

Although the above embodiments have been described with respect to the zoom lens barrel, the present invention is not limited to a general zoom lens barrel, and its effect can be obtained in a lens barrel having a large lens moving amount. It goes without saying that it can be demonstrated.

According to each of the above-described embodiments, the outer diameter of the zoom lens barrel itself can be reduced in accordance with the outer diameter of each lens holding barrel guided by the cam barrel, and each lens holding barrel can be held with respect to the fixed barrel. Since it is possible to maximize the amount of advance and retreat of the barrel in the optical axis direction and the total length of the cam groove for each lens holding barrel provided in the cam barrel, the camera with a large magnification and a large amount of movement of the zoom lens Alternatively, it is possible to provide a zoom lens barrel in which the total length of the lens barrel is short in a camera in which the lens moving amount is large.

[0094]

As described above, according to the present invention, it is possible to provide a compact zoom lens barrel having a short overall length even if the zoom magnification is large.

[Brief description of drawings]

FIG. 1 is a sectional view of a zoom lens barrel showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the constituent members of the first embodiment extended in the optical axis direction.

FIG. 3 is an exploded perspective view showing the constituent members of the first embodiment extended in the optical axis direction.

FIG. 4 is a diagram showing a moving state of each lens group in the first embodiment.

FIG. 5 is a plan view showing a cam groove formed on the peripheral surface of the cam barrel in the first embodiment.

FIG. 6 is a sectional view of a zoom lens barrel showing a second embodiment of the present invention.

FIG. 7 is an exploded perspective view showing the constituent members of the second embodiment extended in the optical axis direction.

FIG. 8 is an enlarged cross-sectional view showing a second lens barrel, a float key and their surroundings in the second embodiment.

FIG. 9 is an exploded perspective view showing the constituent members of the third embodiment extended in the optical axis direction.

FIG. 10 is an exploded perspective view showing the constituent members of the third embodiment extended in the optical axis direction.

FIG. 11 is an exploded perspective view showing the constituent members of the fourth embodiment by extending them in the optical axis direction.

FIG. 12 is an exploded perspective view showing the constituent members of the fourth embodiment extended in the optical axis direction.

FIG. 13 is a cross-sectional view showing a conventional zoom lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Camera main body 2 ... Front cover 3 ... Rear cover 4 ... Back cover 5 ... Light-shielding elastic member 10 ... Fixed cylinder 20 ... Drive cylinder 30 ... Cam cylinder 30a, 30b, 30c ... Cam groove 40 ... First lens cylinder 50, 150 ... Second lens barrel 50a ... Driving roller 50b ... Guide recess 50c ... Front end wall 50e ... Guide notch 60 ... Third lens barrel 41, 51, 61 ... Lens support frame 70 ... Barrier unit 80, 180 ... Float key Reference numeral 80a ... Guide projection 80b, 180b ... Key portion 80c ... Annular base portion 80e ... Fitting hole 90 ... Elastic member 100 ... Flare diaphragm L1 ... First lens group L2 ... Second lens group L3 ... Third lens group

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

[0024]

However, since the guide ring can be arranged only on the outer diameter of the lens group holding frame, the outer diameter of the lens barrel becomes large as a result. Further, the movement amount of the cam ring with respect to the fixed frame is limited by the length of the inner helicoid member in the optical axis direction. Therefore, the length of the cam groove for each lens group holding frame that must be provided in the cam ring itself. Inevitably becomes longer. Therefore, the cam ring itself also becomes long, which also extends the overall length of the lens barrel. Thus, it is at present, it is difficult to supply the camera zoom magnification is large compact.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0086

[Correction method] Change

[Correction content]

The operation of the fourth embodiment thus constructed will be described.

Claims (4)

[Claims] 1. A fixed frame fixed to a camera body, a first cam frame rotatably arranged around an optical axis on an outer circumference of the fixed frame, and an inner circumference of the fixed frame, By rotating the first cam frame with respect to the fixed frame, a second cam frame that advances and retracts in the optical axis direction with respect to the fixed frame, and a second cam frame that is integrated with the second cam frame in the optical axis direction A movable member that is rotatably supported around an axis and that has a fork portion that extends in the optical axis direction is disposed on the inner circumference of the second cam frame, and is cam-coupled to the second cam frame. At the same time, it is integrated with the movable member around the optical axis by being connected to the fork portion of the movable member at the inner peripheral surface thereof, and the second cam frame and the fixed frame cooperate with each other in the optical axis direction. A lens holding frame that moves back and forth in the optical axis direction with respect to the second cam frame; The lens barrel. 2. The lens holding frame provided at the front end of the lens barrel of the lens holding frame is exposed to the outer periphery by advancing in the optical axis direction. The zoom lens barrel described in. 3. The zoom lens barrel according to claim 1, wherein the cam groove provided on the inner peripheral surface of the second cam frame is a bottomed groove. 4. A fixed frame fixed to the camera body, a first cam frame rotatably arranged around the optical axis on the outer circumference of the fixed frame, and an inner circumference of the fixed frame, By the rotation of the first cam frame with respect to the fixed frame, the second cam frame is rotated around the optical axis with respect to the fixed frame and is moved back and forth in the optical axis direction; and the second cam frame. A movable member integrally supported in the optical axis direction and rotatably around the optical axis and having a fork portion extending in the optical axis direction; and a movable member disposed on the inner circumference of the second cam frame, The second cam frame and the fixed frame are integrated with the second cam frame by being cam-coupled with the fork portion of the movable member at the inner peripheral surface thereof and integrated with the movable member around the optical axis. A lens holding frame that moves forward and backward in the optical axis direction with respect to the second cam frame by the relative rotation of Is a zoom lens barrel.