JP2001215387A - Zoom lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assemblability while securing strength in a zoom lens barrel provided with a play removing mechanism in a lens block. SOLUTION: This zoom lens is provided with a front group barrel member having an annular shutter unit at its front end; a front group lens frame supported in the shutter unit so that it can be positionally adjusted in an optical axis direction; a rear group frame fit in the front group barrel member so as to freely move to straight advance in the optical axis direction and supporting a rear group lens; plural straight advance guiding groove in a direction parallel with an optical axis so as to guide to move the front group barrel member in the direction parallel with the optical axis and formed as a recessed part on the outer peripheral surface of the front group barrel member; through- holes formed on the front group barrel member by cutting areas along either boundary surface in the peripheral direction of the plural straight advance guiding grooves; and plural tension springs passing through the respective through-holes and stretched and provided between a hook formed on the front group barrel member and a hook formed on a rear group frame, and energizing and moving the rear group frame in a direction approaching to the front group lens frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a zoom lens barrel.

[0002]

2. Description of the Related Art A zoom lens barrel includes at least two front and rear movable lens groups. The movable lens group is controlled to move forward and backward by a mechanical guide structure such as a cam and a helicoid. However, play is provided at the fitting portion from the viewpoint of assembly workability or in view of a molding error of parts. On the other hand, the movable lens group that constitutes the zoom lens must have an accurate stop position in the optical axis direction, so that a means for removing play after the lens barrel is assembled is required. For example, when the cam pin provided on the rear lens group is guided by the cam groove of the cam ring, a compression coil spring is inserted between the rear lens group and the fixed lens barrel behind the cam lens, and the cam pin is moved to the cam groove. There is known a play removing device that makes contact with one of the guide surfaces. But,
In a zoom lens barrel that has been miniaturized, there is a problem that it is difficult to secure a space for installing a compression coil spring between the lens support member and other lens barrel constituent members. In addition, the compression spring causes buckling when the spring force is increased, and thus requires a guide for preventing buckling. Also, in this type of play removing device, there is no effect on play removal in the front group.

In Japanese Utility Model Laid-Open No. Hei 5-84908 (Japanese Utility Model Application Laid-Open No. Hei 24-24854), the present applicant has a play with a structure in which the front lens group and the rear lens group are biased in a direction approaching each other by a pair of extension coil springs. A removal device was proposed. According to this play removing device, the problem of spring installation space and buckling in the play removing device using the compression spring described above can be solved, and both the front group and the rear group can be biased with a simple configuration. it can.

In such a play removing apparatus using a tension spring, the lens block has a so-called nested structure in which one lens group is guided linearly in the optical axis direction within the support member of the other lens group. If it is
It is advantageous in terms of strength that the outer lens support member is closer to a cylindrical shape. On the other hand, if the lens supporting member has a perfect cylindrical shape, the tension spring that urges both lens groups in the approaching direction is located on the inner surface side of the cylindrical supporting member, and it is difficult to attach the spring. Become. Therefore, there has been a demand for a zoom lens barrel that can easily attach the tension spring without impairing the strength when the tension spring is used as the urging means for removing the play of the lens group.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to improve the assemblability of a zoom lens barrel provided with a play removing mechanism in a lens block while ensuring strength. Aim.

[0006]

SUMMARY OF THE INVENTION The present invention for achieving the above objects has the following objects.
A front group cylinder member having an annular shutter unit at a front end;
A front group lens frame which is supported by the shutter unit so as to be adjustable in the optical axis direction; a rear group frame which is fitted in the front group cylinder member so as to be able to move straight in the optical axis direction and supports the rear group lens; A plurality of rectilinear guide grooves formed in the outer peripheral surface of the cylindrical member as concave portions in a direction parallel to the optical axis for guiding the movement of the front group cylindrical member in a direction parallel to the optical axis; Through holes formed by cutting out a region along one boundary surface in the circumferential direction of the plurality of linear guide grooves; and hooks formed in the front group cylinder member and the rear group frame through each through hole. A plurality of tension springs, which are stretched between the first and second lens units, for biasing the rear group frame to move toward the front group lens frame. According to this zoom lens barrel,
Since the through-hole for passing the tension spring is located continuously to the rectilinear guide groove, which is a concave portion on the outer surface of the front cylinder member, the tension spring can be easily mounted without increasing the opening area of the through-hole. Becomes possible. That is, the assemblability of the lens block can be improved without impairing the strength of the front group cylinder member.

[0007] It is preferable that the front group tubular member has a complete ring portion in front of and behind the through hole, because further strength can be ensured. Of these, it is preferable that a hook on the front group cylinder member side is protruded from the complete annular body portion in front of the through hole toward the outside in the radial direction. A hook is provided on the rear group frame so as to project radially outward, and a notch is formed on the inner peripheral surface of the complete annular body portion behind the through hole to allow the hook of the rear group frame to enter the through hole. By forming, the assemblability can be improved. Further, as means for moving and guiding the rear group frame in a direction parallel to the optical axis, when the front group cylinder member has a plurality of linear guide grooves parallel to the optical axis formed as recesses on the inner peripheral surface, It is preferable that the position of the through hole is different from that of the straight guide groove on the inner peripheral surface in the circumferential direction.

Preferably, a pair of tension springs is provided, and a pair of through holes through which the pair of tension springs pass are formed at radially opposite positions of the front group tubular member. In this case, the position on the outer peripheral surface of the front group cylinder member is varied in the circumferential direction so that 3
A configuration is possible in which two rectilinear guide grooves are formed, and a pair of through holes are formed along two of the three rectilinear guide grooves.

In the above-described zoom lens barrel, a cam groove formed on an inner peripheral surface of a rotatably driven cam ring formed of members separate from the shutter unit, the front group cylinder member, and the rear group frame; A cam follower provided integrally with the frame and engaging with the cam groove, wherein the front group cylinder member and the rear group frame are engaged by a plurality of tension coil springs before the cam follower of the rear group frame is engaged with the cam groove. It is desirable to be in a combined sub-assembly state. Further, the front group cylinder member is guided in a straight line in the optical axis direction, and a helicoid is provided on an outer peripheral surface of an external cylinder provided integrally with the front group cylinder member, and the cam ring is a helicoid screwed into the helicoid of the external cylinder. Is preferably provided on the inner peripheral surface.

[0010]

1 to 3 show side sectional views of a zoom lens camera equipped with a zoom lens barrel 10 according to an embodiment of the present invention, and FIG.
0 is exploded. 1 to 3 show only a part of the front cover 39 of the camera body.
The zoom lens barrel 10 is a two-stage extension type barrel, and performs zooming by changing the relative distance between the front lens group L1 and the rear lens group L2 and the distance of each lens group from the film surface. Focusing is performed by moving the front lens group L1 along the photographing optical axis O. First,
The overall configuration and operation of the zoom lens barrel 10 will be described with reference to the mechanical configuration shown in FIGS. 1 to 4 and the control system block shown in FIG.

An aperture plate 12 having an opening 11 for determining a film exposure area is fixed in the camera body, and a fixed lens barrel 13 is fixed to a front portion of the aperture plate 12. A helicoid ring 14 having a female helicoid 15 on the inner peripheral surface is fixed inside the fixed lens barrel 13. The helicoid ring 14 is further formed with a pair of rectilinear guide holes 16 parallel to the photographing optical axis O. Further, on the inner peripheral surface of the helicoid ring 14, the FPC board 1 for zoom detection is provided.
7, a code plate storage groove 19 for supporting the code plate 18
Are formed long in a direction parallel to the photographing optical axis O. The FPC board 17 for zoom detection is connected to a control circuit 20 in the camera body after being folded forward at the rear end of the code plate housing groove 19.

A male helicoid 22 formed near the rear end of the outer peripheral surface of the cam ring 21 is screwed into the female helicoid 15 of the helicoid ring 14. The cam ring 21 is further provided with a plurality of parallel gears 23 on the same peripheral surface on which the male helicoid 22 is formed. The gear 23 is formed of a parallel gear whose teeth are parallel to the axis of the cam ring 21, and is inclined in the same direction as the direction of the peak of the male helicoid 22. A relief groove 24 corresponding to the area where the gear 23 is formed is formed on the inner peripheral surface of the helicoid ring 14. When the cam ring 21 rotates in accordance with the engagement between the male helicoid 22 and the female helicoid 15, the gear 23 moves inside the escape groove 24 without contact.

The helicoid ring 14 has a gear housing 25 on the side surface, and a zoom gear 26 located in the gear housing 25 is engaged with the gear 23 described above. The zoom gear 26 is composed of multiple pinions having different positions in the optical axis direction, and can mesh with the plurality of gears 23 at the same time. The gears mesh with only the rearmost and front gears 23, respectively. The zoom gear 26 is driven to rotate by a zoom motor 27, and can apply a rotational force to the cam ring 21 via the gear 23. Zoom motor 27
Is a zoom operation member 28 (FIG. 1) provided on the camera body.
The control circuit 20 is controlled to change the driving direction between the lens barrel extending direction and the lens barrel housing direction in accordance with the operation 2).

A linear guide ring 30 is provided inside the cam ring 21. A rectilinear guide plate 31 is fixed to the rear end of the rectilinear guide ring 30. The rectilinear guide plate 31 has a pair of guide protrusions 32 projecting radially outward. The guide projection 32 is slidably engaged with a pair of rectilinear guide holes 16 formed in the helicoid ring 14, whereby the rectilinear guide ring 30 moves in a direction along the photographing optical axis O with respect to the fixed lens barrel 13. You will be guided straight to be able to move. On the outer peripheral surface near the rear end of the linear guide ring 30, an annular groove 34 is formed in the circumferential direction between the linear guide plate 31 and the flange 33. On the other hand, on the inner peripheral surface of the cam ring 21, a guide projection 3 which is movable in the circumferential direction with respect to the annular groove 34 and is fitted so as not to relatively move in a direction parallel to the photographing optical axis O.
5 are formed. The guide projection 35 and the annular groove 34
, The straight guide ring 30 and the cam ring 21
The relative rotation about the photographing optical axis O is possible, and they are coupled so as not to relatively move in a direction parallel to the photographing optical axis O.

The cam ring 21 and the straight guide ring 30 constitute a first extension step of the zoom lens barrel 10.
When the zoom motor 26 rotates the zoom gear 26 in the lens barrel extending direction by the zoom motor 27, the first
, The cam ring 21 is rotated forward by the relation between the female helicoid 15 and the male helicoid 22 from the fixed lens barrel 13 to the front of the optical axis. at the same time,
The rectilinear guide ring 30 supported so as to be rotatable relative to the cam ring 21 moves in a direction parallel to the photographing optical axis O together with the cam ring 21 while being rectilinearly guided by the rectilinear guide holes 16 of the helicoid ring 14.

A brush 37 is fixed to the rear end of the straight guide ring 30. The brush 37 is an FPC board 1 for zoom detection.
7 constitutes a focal length detecting mechanism of the zoom lens together with the code plate 18.
When 1 moves back and forth in the optical axis direction, the sliding position of the brush 37 with respect to the code plate 18 changes, so that a change in the focal length can be detected.

A second feeding cylinder 40 is provided inside the cam ring 21. The second feeding cylinder 40 is composed of an external cylinder 41 and a shutter holding frame 42 (front group cylinder member) that overlap each other near the rear end in the optical axis direction. The overlap portion is fixed by a fixing pin 43. An annular shutter unit 45 is fixed to the front end of the shutter holding frame 42 via a fixing screw 44.

A male helicoid 46 is formed on the outer peripheral surface near the rear end of the external cylinder 41, and the male helicoid 46 meshes with a female helicoid 47 formed on the inner peripheral surface of the cam ring 21. On the other hand, on the outer peripheral surface of the shutter holding frame 42, three rectilinear guide grooves 48 are formed in a direction parallel to the photographing optical axis O. The rectilinear guide ring 30 is divided into three partial cylindrical surfaces 49 located at substantially equal intervals in the circumferential direction, and each of the partial cylindrical surfaces 49 is slidably fitted in the rectilinear guide groove 48 of the shutter holding frame 42. ing. This partial cylindrical surface 49 and the straight guide groove 4
8, the external cylinder 41 and the shutter holding frame 42
Are guided in a direction along the photographing optical axis O with respect to the straight guide ring 30. That is, the second feeding cylinder 40 is guided straight to the camera body.

When the cam ring 21 performs the feeding rotation, a rotational force is applied to the external cylinder 41 due to the screwing relationship between the female helicoid 47 and the male helicoid 46. As described above, the shutter holding frame 42 causes the rectilinear guide ring 30 to move. You are guided straight through. Therefore, the external barrel 41 and the shutter holding frame 42 do not rotate integrally with the cam ring 21 when the cam ring 21 is extended, and are parallel to the photographing optical axis O with respect to the fixed lens barrel 13 according to the relationship between the female helicoid 47 and the male helicoid 46. While being straight forward in the desired direction.

A male helicoid 52 of the front group lens frame 51 holding the front group lens L1 is screwed into a focusing female helicoid 50 formed on the inner periphery of the annular shutter unit 45. The shutter unit 45 includes a driven pin 54 having the drive pin 53 integrated with the front group lens frame 51.
Is engaged. As is well known, the driving pin 53 is rotationally driven by a focusing motor 56 (FIG. 12) by an angle based on the subject distance information and the focal length information obtained by the distance measuring means 55 (FIG. 12). The light is transmitted to the front group lens frame 51 via the driven pin 54, and the front group lens frame 51 (the front group lens L1) moves in the optical axis direction while rotating to perform focusing. In other words, during zooming, the front lens group L1 is integrated with the second feeding cylinder 40 along with the second feeding cylinder 40 as the second feeding cylinder 40 moves forward and backward.
, And can be moved independently in the optical axis direction with respect to the second feeding cylinder 40 to perform focusing. The shutter unit 45 includes a shutter drive motor 57 (FIG. 12), and opens and closes a shutter blade 58 according to the brightness of the subject. A motor drive signal for a focusing operation and a shutter opening / closing operation is sent to the focusing motor 56 and the shutter drive motor 57 via the shutter unit FPC board 59. The bottom surface of one of the three rectilinear guide grooves 48 (indicated by reference numeral 48B) is formed in a planar shape to support the shutter unit FPC board 59.

The rear lens group L2 is held by a rear lens group frame (rear group frame) 60. The rear group lens frame 60 has three guide projections 61 extending radially outward,
A cam pin 62 is fixed to the tip of each guide protrusion 61. On the inner peripheral surface of the shutter holding frame 42, the three rectilinear guide grooves 63, which are different from the three rectilinear guide grooves 48 on the outer peripheral surface in the circumferential direction, are elongated in the direction along the photographing optical axis O.
The guide protrusion 61 of the rear lens group frame 60 is slidably engaged with the rectilinear guide groove 63. As described above, the shutter holding frame 42 is guided straight by the straight guide ring 30, and the rear group lens frame 60 is guided straight by the shutter holding frame 42. Therefore, both the second feeding cylinder 40 and the rear group lens frame 60 It will be guided straight in the optical axis direction.

The guide projection 61 of the rear lens frame 60
The cam pins 62 protruding from the cam ring 21 are inserted into through cutouts 64 and 65 formed in the shutter holding frame 42 and the appearance cylinder 41, respectively, and the leading ends thereof are fitted into inner cam grooves 66 formed on the inner peripheral surface of the cam ring 21. I have. As the cam pins 62 move in the through cutouts 64 and 65, the rear lens group frame 60 having the cam pins 62 moves the shutter holding frame 42 and the external cylinder 41 in the direction along the photographing optical axis O. Relative movement is allowed. The inner cam groove 66 has a predetermined skewed shape with respect to the photographing optical axis O. When the cam ring 21 rotates in response to the driving of the zoom motor 27, the inner cam groove 66 moves straight through the straight movement guide ring 30 and the shutter holding frame 42. The rear lens group frame 60 thus moved is moved along a predetermined locus in a direction along the photographing optical axis O according to the shape of the inner cam groove 66 with which the cam pin 62 is engaged.

The external cylinder 41 of the second feeding cylinder 40 and the cam ring 21
A light-blocking member 67 that blocks light between the first and second feeding steps is provided therebetween. Further, between the cam ring 21 and the fB adjusting ring 68 in the camera body, a light blocking member 69 for preventing stray light from entering the film surface side from outside the first feeding step portion.
Is provided. The fB adjustment ring 68 can change the position in the optical axis direction of the entire zoom lens system by changing its rotational position.

The zoom lens barrel 10 having the above configuration operates as follows. When the zoom motor 27 is driven in the extending direction from the retracted state of FIG. 1 or the wide end of FIG.
The cam ring 21 is rotated and fed out of the helicoid ring 14, and the rectilinear guide ring 30 moves forward together with the cam ring 21 while being rectilinearly guided by the rectilinear guide holes 16 of the helicoid ring 14. When the cam ring 21 performs the rotation feeding, the rear lens group L2 moves forward in the first feeding step due to the relationship between the inner cam groove 66 and the cam pin 62. In addition, straight guide ring 30
The second feeding cylinder 40 guided straight forward by the movement of the cam ring 21 moves forward along the optical axis in response to the rotation of the cam ring 21, and the front lens group L <b> 1 moves forward together with the second feeding cylinder 40. When the zoom motor 27 is driven in the storage direction from the telephoto end in FIG. 3, the zoom lens barrel 10 performs the reverse operation. That is, the second feeding cylinder 40 is connected to the first feeding step (the cam ring 21 and the linear guide ring 3).
0), the first dispensing step is
Move in the direction to be stored in the camera body. As described above, the zoom lens barrel 10 including the two-stage extending portion focuses on the combined operation of the change in distance between the front lens group L1 and the rear lens group L2 with respect to the film surface and the relative movement of each lens group. Change the distance. Further, the shutter unit 4
The focusing lens 56 is moved by the focusing motor 56 in the direction parallel to the photographing optical axis O to perform focusing.

In this embodiment, when the main switch 29 (FIG. 12) of the zoom lens camera is off, the zoom lens barrel 10 is in the storage position of FIG. 1, and when the main switch 29 is turned on, the zoom lens barrel is turned on. 10 is extended from the storage position to the wide end in FIG. The operator can arbitrarily move the zoom lens barrel 10 forward and backward through the zoom operation member 28 from the wide end to the tele end in FIG.

In the zoom lens barrel constructed as described above, a pair of tension coil springs (tensile springs) are provided between the second extension barrel 40 and the rear lens group frame 60 to urge the two in a direction to approach them. ) 70 is stretched. The extension coil spring 70 is for removing the play of each of the front lens group L1 and the rear lens group L2 to make the lens position accurate in the optical axis direction. The zoom lens barrel 10 of the present embodiment has a feature in the configuration for providing the extension coil spring 70, and the configuration will be described in detail with reference to FIGS.

As described above, the shutter holding frame 42 is
The outer peripheral surface has three rectilinear guide grooves 48 into which the partial cylindrical surfaces 49 of the rectilinear guide ring 30 fit. Each straight guide groove 48
Is formed as a concave portion having a pair of parallel guide surfaces (boundary surfaces) 71 and 72 provided at intervals corresponding to the width of the partial cylindrical surface 49. The sliding contact of the side surface guides the shutter holding frame 42 straight in the optical axis direction. In the present description, of the pair of parallel guide surfaces, the one located in the clockwise direction when the shutter holding frame 42 is viewed from the front of the optical axis is referred to as the parallel guide surface 71, and the one located in the counterclockwise direction is referred to as the parallel guide surface 71. It is referred to as a parallel guide surface 72 (see FIG. 10).

In one of the three rectilinear guide grooves 48, designated by reference numeral 48A, the parallel guide surface 71 is
The outer peripheral surface and the inner peripheral surface of the shutter holding frame 42 are radially provided in an area adjacent to the linear guide groove 48A in front of the parallel guide surface 71 and near the rear end. A penetrating hole 73 is formed. The through hole 73 is formed to be long in the axial direction of the shutter holding frame 42, but neither the front end nor the rear end thereof communicates with the front end face and the rear end face of the shutter holding frame 42. That is, the peripheral surface of the shutter holding frame 42 at the front part of the through hole 73 is bridged by the front bridge part 74 to form a complete ring. Further, the peripheral surface of the shutter holding frame 42 behind the through hole 73 is bridged by a rear bridge 76 to form a complete ring. The partial parallel guide surface 71 is formed at the circumferential end of the rear bridge portion 76. A spring hooking projection 75 projects outward in the radial direction from the front bridge portion 74, and the tip end of the spring hooking projection 75 is bent forward of the shutter holding frame 42. The front bridging portion 74 is formed on the inner diameter side from the bottom surface of the straight guiding groove 48A. The groove 48A is located on the inner diameter side of the radial position of the bottom surface. As shown in FIG. 10, a rear bridging portion 76 having a parallel guide surface 71 is located behind the spring hooking projection 75, and the spring hooking projection 75 and the rear bridging portion 76 are arranged in the radial direction. Do not overlap at

Similarly, in one of the three rectilinear guide grooves 48, designated by reference numeral 48B, a parallel guide surface 72 is provided only in a part near the rear end of the shutter holding frame 42, and the parallel guide surface 72 is provided. The straight guide groove 48 ahead of 72
In a region adjacent to B, a through-hole 81 is formed that penetrates the outer peripheral surface and the inner peripheral surface of the shutter holding frame 42 in the radial direction. The front portion of the through hole 81 is bridged by a front bridge portion 82, and the rear portion is bridged by a rear bridge portion 84, and each is a complete ring portion. The above partial parallel guide surface 72 is formed at the circumferential end of the rear bridge portion 84. Front bridge portion 8 located on the inner diameter side from the bottom surface of straight guide groove 48B
2, a spring hook projection 83 protrudes. Like the above-mentioned spring hooking projection 75, the tip end of the spring hooking projection 83 is located on the inner diameter side with respect to the bottom surface of the rectilinear guide groove 48B, and the spring hooking projection 83 and the rear bridge on which the parallel guide surface 72 is formed. The entangled portion 84 does not overlap in the radial direction.

As shown in FIG. 10, the through hole 73 and the through hole 81 are formed at radially opposite positions of the shutter holding frame 42. Further, the spring hooking projections 75 and 83 provided at the front portions of the through holes 73 and 81 are also at radially opposed positions.

That is, in the shutter holding frame 42, through-holes 73 and 81 are formed by partially removing a region along one boundary surface (parallel guide surface) in the circumferential direction of the linear guide grooves 48A and 48B. The front and rear of the through holes 73 and 81 are complete rings that are bridged by bridge portions. As described above, the shutter holding frame 42 has three rectilinear guide grooves 63 on the inner peripheral surface for guiding the rear lens group frame 60 in a direction parallel to the photographing optical axis O. Both the hole 73 and the through hole 81 are circumferentially different in position from these rectilinear guide grooves 63. The linear guide groove 63 is formed on the linear guide groove 48 formed on the outer surface of the shutter holding frame 42.
The linear guide groove 48, the through holes 73 and 81, and the linear guide groove 63 do not overlap in the radial direction.

The rear group lens frame 60 has a spring hook projection 75
And a pair of spring hooking projections 85 and 86 are formed at radially opposite positions in correspondence with the positions of the spring hooking projections 83. The one spring hooking projection 85 is not shown in the perspective views of FIGS. 4, 5, and 11. The tip of each of the spring hook projection 85 and the spring hook projection 86 is bent toward the rear of the rear lens frame 60. The rear projection lens frame 6 is set so that the guide projection 61 fits into the straight guide groove 63.
0 is attached to the shutter holding frame 42 from behind, the spring hooking projections 85 and 86
3 and into the through hole 81. A cutout 87 is formed in each of the rear bridge portion 76 and the rear bridge portion 84 to allow the spring hook protrusion 85 and the spring hook protrusion 86 to enter. The spring hook projection 85 that has entered the through hole 73 is located on a straight line with the spring hook projection 75 in the optical axis direction, and the spring hook projection 86 that has entered the spring hook projection 83 is directly aligned with the spring hook projection 83 in the optical axis direction. Located on the line (Fig. 1
To FIG. 3).

In the present embodiment, the above lens block is
At the time of assembly, it can be brought into a sub-assembly state. At the time of assembly, for example, the shutter unit 45 and the shutter holding frame 42 are fixed using fixing screws 44, and
Thereafter, the rear group lens frame 60 is inserted from behind the shutter holding frame 42 such that the positions of the spring hook projections 85 and 86 match the positions of the spring hook projections 75 and 83, respectively. Then, the three guide protrusions 61 provided on the rear lens frame 60 are fitted into the three rectilinear guide grooves 63 to be guided rectilinearly.
2 project radially outward through the through cutout 64. At the same time, a pair of spring hook projections 85 and 86 projecting from the rear lens frame 60 pass through the notches 87 and the through holes 73 and 8.
Enter within 1.

Subsequently, hooks 88 at both ends of the tension coil spring 70 are hooked onto the spring hooking projections 75 and 85, respectively. Similarly, the tension coil springs 70 are hooked on the spring hooking projections 83 and the spring hooking projections 86, respectively. Hook portions 88 at both ends. The rear lens group frame 60 is held by the pair of extension coil springs 70 so as not to fall off from the shutter holding frame 42. With the above assembly, the shutter unit 45 and the shutter holding frame 42 and the rear group lens frame 42 supporting the rear group lens L2 are brought into the sub-assembly state in FIG. In this embodiment, the shutter holding frame 42
The shutter unit 45 and the shutter holding frame 42 are fixed first, and then the rear lens group frame 60 is attached. The shutter unit 45 may be fixed after the and the rear lens frame 60 are connected by the tension spring 70.

When the external cylinder 41 is connected to the shutter holding frame 42 using the fixing pins 43 from the sub-assembly state shown in FIG. 11, the pair of cam pins 62 project radially outward through the through cutouts 65. Subsequently, the external cylindrical surface 49 of the rectilinear guide ring 30 is fitted into the rectilinear guide groove 48 on the outer peripheral surface of the shutter holding frame 42, and the pair of cam pins 62 is further fitted into the inner cam groove 66 of the cam ring 21. Male helicoid 46 of cylinder 41 and female helicoid 4 on inner peripheral surface of cam ring 21
7 is screwed. Thus, when the cam ring 21 is driven to rotate, the second feeding cylinder 40 moves forward and backward with respect to the cam ring 21 in the optical axis direction, and the rear lens group frame 60 is moved to the inner cam groove 6.
The above-described zoom lens barrel 10 which moves in the cam ring 21 in the optical axis direction by the guide 6 can be configured. In addition,
From the sub-assembly state shown in FIG. 11, the straight guide ring 30 may be assembled first, and then the external cylinder 41 may be fixed to the shutter holding frame 42.

According to the above configuration, the rear group lens L2 is moved forward by the pair of extension coil springs 70,
Are biased to move backward. Therefore, the cam pin 62 abuts on the front side wall of the inner cam groove 66, and the male helicoid 46 of the external appearance cylinder 41 constituting the second feeding cylinder 40 has a rear surface facing the front surface of the male helicoid 47 of the cam ring 21. And play is eliminated.
Therefore, the lens stop position can be reliably controlled. Further, regarding the second feeding cylinder 40, when the second feeding cylinder 40 advances forward, the light blocking member 67
By resistance. Since the direction of this resistance is the same as the direction in which the second feeding cylinder 40 is urged by the tension coil spring 70, the lens stop position can be controlled more accurately. Advantages of using the tension spring as the urging means for removing play as described above are that the arrangement space is less restricted than the compression spring, the guide means for preventing buckling can be eliminated, and a simple configuration. For example, the play removal effect of both the front lens group and the rear lens group can be obtained.
Further, the lens block including the front lens group L1 and the rear lens group L2 is connected by the tension coil spring 70 to be in a sub-assembly state, so that it is easy to handle.

Further, in addition to the above advantages obtained by using the tension spring as the play removing means, in the configuration of the present embodiment, the shutter holding frame 4 constituting the lens block is further provided.
2 can be improved while ensuring the strength. That is, when the tension coil spring 70 is stretched,
Spring hook projection 7 exposed on the outer surface side of shutter holding frame 42
Hooks 88 of both ends of the tension coil springs 70 are attached to the spring hooking projections 85 and 86 on the rear lens frame 60 side exposed on the outer surface side of the shutter holding frame 42 through the through holes 73 and 81. Since it is only necessary to lock the spring, it is easier to attach the spring than when the spring hooking portion is located on the inner diameter side of the shutter holding frame 42 and is not exposed on the outer surface side.

This through hole does not merely penetrate the inner and outer surfaces of the shutter holding frame 42, but also a rectilinear guide groove 48 formed as a concave portion on the outer circumferential surface of the shutter holding frame 42.
(48A, 48B) It is formed by cutting out a region along the boundary surface in the circumferential direction. In the shutter holding frame 42, a portion of the rectilinear guide groove 48 formed as a concave portion is thin, and the bottom surface of the rectilinear guide groove 48 is also formed in the shutter holding frame 42.
Of the outer peripheral surface of the shutter guide frame 48, the depth of the through holes 73 and 81 is more continuous with the bottom surface of the linear guide groove 48 than when the outer peripheral surface of the shutter holding frame 42 other than the linear guide groove 48 is cut off. Resection can be shallower. If the through hole is shallow, the work of stretching the tension coil spring 70 passed through the through hole becomes simpler. In other words, when the radial position of the spring hook projection (particularly, the spring hook projection of the rear lens frame 60) is constant, the spring hook projection is
Rather than being located inside the through hole where both wall surfaces are deeper, one located in the through hole where the one wall surface is shallow and continuous with the straight guide groove 48 faces the straight guide groove 48. Since the side is open, the tension coil spring 70 can be easily stretched.

For comparison with this embodiment, the straight guide grooves 4
FIG. 13 shows a comparative example in which a through hole for inserting a spring is provided at a position distant in the circumferential direction from FIG. In FIG.
The conditions other than the point where the formation positions of 0 and 91 are different are the same as those of the previous embodiment. That is, the circumferential width of the through holes 90 and 91 is the same as that of the aforementioned through holes 73 and 81, and the spring hook projection 75 is provided. , 83 (85, 86) in the radial direction. However, as is apparent from the comparison between FIG. 10 and FIG. 13, in the comparative example of FIG. 13, the wall surfaces on both sides of the through holes 90 and 91 are high, and the spring hooking projection is located deep inside the through holes 90 and 91. On the other hand, in the present embodiment in FIG. 10, the spring hook projection is exposed at a shallow position when viewed from the straight guide groove 48 side. Is easy. In order to easily attach the spring in the comparative example of FIG.
Although it is conceivable to increase the circumferential width of 0, 91, increasing the opening area of the through-hole requires increasing the shutter holding frame 42.
This is not desirable from the viewpoint of securing strength. On the other hand, in the through holes 73 and 81 of the above-described embodiment, it is not necessary to increase the opening area in order to improve the spring mounting property, and if there is a minimum opening area through which the extension coil spring 70 can pass. Since it is sufficient, the influence on the strength of the shutter holding frame 42 can be minimized.

Further, in the shutter holding frame 42 of the present embodiment, the front and rear positions of the through holes 73 and 81 are connected by a bridging portion to form a complete ring, which contributes to securing the strength. In particular, the spring hooking projections 85 and 86 of the rear lens frame 60 enter the through holes 73 and 81 from the rear, while the spring hooking projections 85 and 86 enter the rear bridge portions 76 and 84.
The notch 87 is formed to allow the entry of the gas, so that it is possible to secure the strength and not to deteriorate the assemblability.

In the shutter holding frame 42 of the embodiment, a rectilinear guide groove 63 is also formed as a concave portion on the inner surface side of the shutter holding frame 42, and the through holes 73 and 81 overlap with the rectilinear guide groove 63. The positions are changed in the circumferential direction so as not to be disturbed. In principle, the inner wall surfaces of the through holes 73 and 81 in the radial direction are provided with the rear group lens frame 6 instead of the straight guide grooves 63.
Although it is possible to use it as a guide surface for zero, in such a configuration, the extension coil spring 70 and the spring hooking projection are arranged in the radially outer region of the through holes 73 and 81, and the guide is provided inward thereof. Since the surface must be formed, the size of the shutter holding frame 42 in the radial direction increases, which is contrary to the demand for downsizing the lens barrel. Therefore, when the guide structure is also provided on the inner surface side of the shutter holding frame 42, the circumferential positions of the through holes 73 and 81 and the linear guide groove 63 are changed as in the present embodiment in order to avoid an increase in the diameter of the shutter holding frame 42. It is preferable to make them different. The straight guide groove 63 is a groove with a bottom, and the through cutout 64 is formed only in the moving area of the cam pin 62 on the rear end side, so that the straight guide groove 63 is stronger than a through groove over the entire length. It is economically advantageous.

[0042]

As described above, according to the present invention, in a zoom lens barrel provided with a play removing mechanism in a lens block, assemblability can be improved while ensuring strength.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a zoom lens barrel according to an embodiment of the present invention in a housed state.

FIG. 2 is a side sectional view at a wide end of the zoom lens barrel of FIG. 1;

FIG. 3 is a side sectional view at a tele end of the zoom lens barrel in FIG. 1;

FIG. 4 is an exploded perspective view of a zoom lens barrel.

FIG. 5 is an exploded perspective view showing a shutter unit, a shutter holding frame, a rear lens group frame, and a rectilinear guide ring in an exploded state.

FIG. 6 is a front perspective view showing a shutter holding frame alone;

FIG. 7 is a front perspective view showing the shutter holding frame by itself and viewed from a different angle from FIG. 6;

FIG. 8 is a rear perspective view showing the shutter holding frame alone.

FIG. 9 is a rear perspective view showing the shutter holding frame by itself and viewed from an angle different from that of FIG. 8;

FIG. 10 is a front view of the shutter holding frame.

FIG. 11 is a perspective view showing a sub-assembly state in which a shutter unit, a shutter holding frame, and a rear lens group frame are combined.

FIG. 12 is a block diagram illustrating a control system of a zoom lens camera equipped with the zoom lens barrel according to the present embodiment.

FIG. 13 is a front view of a shutter holding frame, showing a comparative example in which the positions of through holes for inserting springs are different.

[Explanation of symbols]

 Reference Signs List 10 zoom lens barrel 13 fixed barrel 21 cam ring 30 rectilinear guide ring 40 second extension cylinder 41 external cylinder 42 shutter holding frame (front group cylinder member) 45 shutter unit 46 male helicoid 47 female helicoid 48 48A 48B 63 linear guide groove 49 Partial cylindrical surface 51 Front group lens frame 60 Rear group lens frame (Rear group frame) 61 Guide projection 62 Cam pin 66 Inner cam groove 70 Tension coil spring (Tension spring) 71 72 Parallel guide surface (boundary surface) 73 81 Through hole 74 82 Front bridge part 75 83 85 86 Spring hook projection 76 84 Rear bridge part 87 Notch 88 Both ends hook part L1 Front group lens L2 Rear group lens O Imaging optical axis

Claims (9)

[Claims] 1. A front group cylindrical member having an annular shutter unit at a front end portion; a front group lens frame supported by the shutter unit so as to be capable of adjusting a position in an optical axis direction; A rear group frame that supports the rear group lens and that is movably fitted in a straight line; formed as a concave portion on the outer peripheral surface of the front group cylinder member to guide the front group cylinder member in a direction parallel to the optical axis; A plurality of rectilinear guide grooves in a direction parallel to the optical axis;
A through-hole formed by cutting out a region along one circumferential surface of the plurality of rectilinear guide grooves in the front cylinder member; and a hook formed in the front cylinder member through each through-hole. Stretched between the hook formed on the rear group frame,
A zoom lens barrel comprising: a plurality of tension springs for urging the rear group frame to move in a direction approaching the front group lens frame. 2. The zoom lens barrel according to claim 1, wherein said front lens group member has a complete ring portion in front of and behind said through hole. 3. The zoom lens barrel according to claim 2, wherein said hook protrudes radially outward from a complete annular portion in front of said through hole. 4. The zoom lens barrel according to claim 2, wherein the rear group frame is provided with the hook protruding radially outward, and a complete ring portion provided behind the through hole. A zoom lens barrel having a notch formed on an inner peripheral surface thereof to allow a hook of a rear group frame to enter into the through hole. 5. The zoom lens barrel according to claim 1, wherein the front group barrel member is formed as a concave portion on an inner peripheral surface, and the rear group frame is parallel to the optical axis. A zoom lens barrel having a plurality of rectilinear guide grooves parallel to the optical axis for guiding the movement of the zoom lens, wherein the through-holes are circumferentially different in position from the rectilinear guide grooves on the inner peripheral surface. 6. The zoom lens barrel according to claim 1, wherein a pair of the tension springs is provided, and a pair of through holes through which the pair of tension springs pass is provided.
A zoom lens barrel formed at a position radially opposite to the front cylinder member. 7. The zoom lens barrel according to claim 6, wherein three linear guide grooves are formed on the outer peripheral surface of the front group member at different positions in the circumferential direction. A zoom lens barrel formed along two of the three rectilinear guide grooves. 8. The zoom lens barrel according to claim 1, further comprising a rotatably driven cam ring formed of a member separate from the shutter unit, the front group cylinder member, and the rear group frame. A cam groove formed in the peripheral surface; and a cam follower integrally provided in the rear group frame, which engages with the cam groove. The front group cylinder member and the rear group frame cam the cam followers of the rear group frame. A zoom lens barrel which is set in a sub-assembly state in which the plurality of tension coil springs are connected before engaging the groove. 9. The zoom lens barrel according to claim 8, wherein the front cylinder member is guided linearly in an optical axis direction,
A zoom lens barrel comprising: a helicoid provided on an outer peripheral surface of an outer cylinder provided integrally with the front group cylinder member; and the cam ring has a helicoid screwed into the helicoid of the outer cylinder on an inner peripheral surface.