JP3342480B2 - Lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lens barrel having a cam mechanism.

[0002]

2. Description of the Related Art In recent years, there has been a demand for downsizing of a zoom lens barrel alone or a camera with a zoom, and the zoom lens barrel is shortened when not in use. As a technique therefor, a cam means for moving a lens group in a zoom lens barrel for changing a zoom value is provided with a cam means for changing a zoom value and shortening (for shortening of the zoom lens barrel itself or in a camera). And a cam means portion for retraction. And
The cam means must move and drive the lens frame precisely because of the nature of handling optical components as lenses, and the gap between the cam follower of the lens frame holding the lens group and the groove of the cam means engaging with it is zero. It is packed close to. Further, a technique often used as a structure for moving the lens frame is, for example, to provide a rectilinear groove in a fixed frame or the like, to form an oblique cam groove on a cam ring rotating around the fixed frame, and to provide a cam follower provided in the lens frame. Into the straight groove and the cam groove. When the cam ring is rotated in the lens barrel configured as described above, the cam follower advances and retreats in the lens barrel by a propulsive force received from the cam groove through the straight groove.

[0003]

However, as described above, the cam groove and the rectilinear groove are dimensionally different from the cam follower.
In addition to having only a small gap, the positions of the cam grooves, the straight grooves and the cam followers on the frame member in a precise sense include processing errors, and in some cases, the necessary gaps described above are lost. As a result, in a state where the groove side surface of the cam groove and the groove side surface of the rectilinear groove slightly bite into the cam follower, it can be said that the cam groove moves forward and backward while generating friction. This causes a loss of driving force for moving the lens barrel forward and backward, and the driving force has to be increased unnecessarily. Therefore, a large driving force is required even when the lens barrel is retracted, and wasteful energy must be consumed.

An object of the present invention is to provide a lens barrel which has a simple structure which solves the above-mentioned conventional problems and which has a shortened lens barrel or suppresses energy loss during collapsing.

[0005]

In order to achieve the above-mentioned object, the present invention provides a lens barrel which performs zooming and collapsing operations, wherein the lens barrel moves in the optical axis direction during the zooming and collapsing operations of the lens barrel. A moving frame, a cam follower provided in the moving frame, a groove as a zoom area for fitting and slidingly contacting the cam follower for the zooming and moving the moving frame, and a groove formed continuously from the groove, A cam groove having a wide groove width and a groove portion as a collapsible area for moving the moving frame by slidingly contacting with the cam follower for the collapsing operation.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to illustrated examples. 1, 2 and 3 are an exploded perspective view of a lens barrel to which an encoder device of a zoom lens according to an embodiment of the present invention is applied and a longitudinal sectional view in a collapsed state.

This zoom lens barrel enables zooming, focusing and collapsing operations. The main configuration of this zoom lens barrel is a fixed frame 1
And a fixed mirror frame 2 which is a first frame fixed to the fixed frame 1
, A focus ring 3, an inner zoom ring 4, an outer zoom ring 5, which is a second frame, and a first lens, which is a focusing lens group frame.
A group frame 6, a first moving frame 7 holding a second group lens which is also a focusing lens group frame, and a second moving group 7 holding a third group lens other than the focusing lens. Moving frame 8
A separate moving frame 9 for holding the fourth group lens, a fifth group lens holding frame 10, and first, second, third, fourth, and fifth group lenses 20 held directly or indirectly by the frames. , 2
1, 2, 23, and 24 (see FIG. 3), a focus drive unit 11, a zoom drive unit 12, an aperture unit 13, and a zoom encoder unit. The lens groups 20 to 24 are not shown in FIGS. 1 and 2 but are shown in the cross-sectional view of FIG.

The fixed frame 1 is, as shown in FIG.
Spacers 14 and 15 are mounted on the mirror box 16 of the camera body.
Is fixed through. The distance between the fixed frame 1 and the mirror frame 17 mounted on the mirror box 16 and holding the movable reflection mirror 19 is adjusted by the spacers 14 and 15. The fixed frame 1 has a hole 1a for supporting the fifth group lens frame 10 at the center thereof, and a fitting portion 1d for fitting the fixed lens frame 2 integrally with the mounting flange portion. Further, a cylindrical portion 1e for supporting the inner zoom ring 4 so as to be rotatable around the optical axis O is provided. A sliding pin 1g for regulating the movement of the inner zoom ring 4 in the optical axis direction is screwed with a screw 1f. It is fixed on the cylindrical portion 1e.

The fixed frame 1 is provided with a fitting hole 1b and a fitting elongated hole 1c for slidably supporting the second group main rod 7e and the second group sub rod 7f in the optical axis direction. . Further, the focus drive unit 11 is mounted on a mounting surface 1h provided by cutting out a part of the cylindrical portion 1e. The zooming drive unit 12 is also attached to the fixed frame 1 in the same manner. Further, the aperture unit 1
3 is also pivotally mounted on the fixed frame 1 via the shaft hole 25a.

The fixed frame 2, which is the first frame, has a cylindrical shape, and is fixed to the fitting portion 1d of the fixed frame 1 with its inner peripheral portion 2a fitted. The cylindrical portion has guide linear grooves 2b for the first group frame 6 and the first moving frame 7 along the optical axis O.
2c and a bottomed inner circumferential groove 2g for regulating the axial position of the focus ring 3 along the circumferential direction of the inner circumference on the fixed frame 1 side.
Similarly, elongated holes 2d as guide portions for regulating the axial position of the contact stand 13 are provided along the circumferential direction of the cylindrical portion opposite to the fixed frame side. The straight groove 2c
As shown in the developed view of FIG. 15, a groove 2h in a zoom region having a width equal to the outer diameter of the roller 7j to be fitted, and a groove 2i in a collapsed region having a width larger than the outer diameter. Shall be formed from The groove 2i is a portion used when the lens barrel is collapsed.

The focus ring 3 has a ring shape, the outer periphery of which is fitted with the inner periphery 2a of the fixed lens frame 2, and the inner periphery of which is engaged with the output gear 11a of the focus drive unit 11. A tooth gear 3e is provided. A sliding pin 3b is provided on the pin fixing portion of the outer peripheral portion.
Is fixed by the screw 3a. The slide pin 3b is slidably fitted in the inner peripheral groove 2g of the fixed lens frame 2, and prohibits the movement of the focus ring 3 in the optical axis O direction. A sliding pin 3d for moving the zoom ring 5 in the optical axis direction is fixed to the pin fixing portion 3g on the projection that is loosely fitted to the inner periphery of the outer zoom ring 5, which is the second frame, with a screw 3c. Is done. The sliding pin 3d is slidably fitted in the focus cam groove 5b of the zoom ring 5.

The inner zoom ring 4 is a cylindrical member, the inner peripheral portion of which is rotatably fitted to the cylindrical portion 1e of the fixed frame 1, and the inner peripheral groove 4d provided in the inner peripheral portion. The sliding pin 1g of the fixed frame 1 is fitted in the zoom ring 4, and the movement of the zoom ring 4 in the optical axis direction is prohibited. The inner peripheral portion includes the zoom drive unit 1 driven based on a zoom control signal.
An internal gear 4c with which the second output gear 12a meshes is provided.

The zoom ring 4 is provided with a second moving frame 8 for holding the third and fourth lens groups, and cam grooves 4a and 4b as cam means for driving another moving frame 9 for zooming. The cam grooves 4a and 4b have the second
Moving frame 8, sliding pin 8j fixed to another moving frame 9,
The cam grooves 4g and 4h in the collapsed area corresponding to the lens barrel collapsed state having no displacement in the optical axis direction, respectively, as shown in the developed view of FIG.
And cam grooves 4i and 4j in a zoom region having a zoom displacement in the optical axis direction. A roller 4f, which is a connecting member fitted into the rectilinear groove 5a of the outer zoom ring 5, is rotatably supported by a pin 4e on the outer peripheral portion.

The outer zoom ring 5 is a cylindrical member, and its outer peripheral portion and inner peripheral portion are rotatably or slidably fitted into the fixed lens frame 2 and the first group frame 6, respectively. Then, a straight groove 5a is provided along the optical axis O,
The inner zoom ring 4 performs a rotational drive corresponding to the zoom amount via a roller 4f fitted in the groove.
Further, the main zoom ring 5 is provided with a focus cam groove 5b corresponding to the focusing extension amount, and the sliding pin 3d of the focus ring 3 is fitted therein. Therefore, the main zoom ring 5 moves straight in the optical axis direction by the focusing amount. Moved.

Further, the zoom ring 5 is provided with cam grooves 5c and 5d as second cam means. The first and second group rollers 6b and 7j supported by the first group frame 6 and the first moving frame 7 are provided in the cam grooves 5c and 5d.
Is inserted. Accordingly, the first group frame 6 and the first moving frame 7 are displaced in the direction of the optical axis O in accordance with the rotation of the main zoom ring 5 by zooming or the axial movement by focusing. The cam grooves 5c, 5c
d is for moving the first group frame 6 or the first moving frame 7 to the retracted position when the camera is not used, and the cam units 5i and 5h in the zoom area for providing the driving positions during focusing and zooming, respectively. And cam portions 5j and 5g in the collapsed area for retraction into the camera body. Note that the groove width of the cam portion 5g is determined by the roller 7 to be inserted.
It is formed larger than the outer diameter dimension of j so that interference between the lens groups does not occur at the time of the above-described retraction (see FIG. 15).

The present zoom ring 5 is provided with a stepped square hole 5f for guiding a contact piece 13 for a zoom encoder, which will be described later, at a position corresponding to the elongated hole 2d of the fixed lens frame 2. I have.

The first group frame 6, to which the first group lens holding frame 6c is screwed, has a cylindrical shape. The outer peripheral portion is slidably fitted into the outer zoom ring 5. A first group roller 6b is rotatably attached to a corresponding portion 6f of the cam groove 5c on the outer peripheral portion by a pin 6a. The first group roller 6b is connected to the cam groove 5
c and the rectilinear groove 2b of the fixed lens frame 2.
Accordingly, the first group frame 6 is moved in accordance with the rotation or the straight movement of the zoom ring 5 while being guided straight in the direction of the optical axis O by the straight groove 2. In addition, a concave portion 6e that forms a thin portion along the axial direction is provided on the inner periphery of the first group frame 6. The recess 6e serves as a relief for a second group drive plate 7h to be described later.

The first group lens 20 is held by the first group lens holding frame 6c, the lens spacing is adjusted by the spacer 6d, and the first group lens 20 is supported by the first group frame 6.

The first moving frame 7 holds the second group lens frame 7a to which the second group lens 21 is attached. Then, as shown in FIG. 4, two U-shaped notches 7b are provided in the outer shape portion so as to face the lens frame optical axis in order to fix and support the rod, which is a rod-shaped guide member. I have. The surface formed by the two sides 7c of the notch is formed by molding or machining so as to be parallel to the optical axis of the lens frame. A second group main rod 7 which is a rod-shaped guide member is provided in the notch 7b.
e or one end of the second group sub-rod 7f is inserted, and the rods 7e and 7f are pressed and fixed by the slope of the fixing piece 7 through the screw 7g using the U-shaped fixing piece 7. Then, since each rod is pressed by the slope of the fixing piece 7, the rods 7e and 7f are respectively connected to the notches 7b.
Are brought into contact with the two sides 7c, respectively, and as a result, they are mounted in parallel with the optical axis of the lens frame.

Then, the rods 7e, 7f mounted are mounted.
The other ends of the fitting frame 1 are the fitting holes 1b,
c to be slidably inserted. Therefore, the second group lens 21
Is movable along the optical axis O integrally with the rods 7e and 7f without rotating. Also, in the middle part of the rods 7e and 7f,
A second moving frame 8 of another lens holding frame slidably supported and guided by these rods is inserted.

A second group drive plate 7h for driving in the axial direction and extending in the optical axis direction is fixed to the first moving frame 7 via screws. And this driving plate 7h
A roller 7j is rotatably attached to a leading end of the roller 7 via a pin 7i. The roller 7j is fitted into the cam groove 5c of the outer zoom ring 5 and the rectilinear groove 2c of the fixed lens frame 2 as described above. Accordingly, with the rotation and axial movement of the outer zoom ring 5, the first moving frame 7 moves in the direction of the optical axis O via the driving plate 7h, and the second group lens 21 also moves. Can be The driving plate 7h
The concave portion 6e provided in the first group frame 6 due to its arrangement
It is located in the space part of.

The second moving frame 8 holds the third group lens 22, and is fixed to a position opposite to the optical axis on the first moving frame 7 in the second group main rod 7e. And the sub-rod 7f is slidably supported in the optical axis direction. That is, the rod 7e is fitted into the notch 8c of the second moving frame 8, while the sub rod 7f is fitted with a fitting member (hereinafter, referred to as a fitting member) as shown in the mounting state diagram of FIG.
The moving frame 8 is supported via a sleeve 8a. The sleeve 8a is fixed to the moving frame 8 with an adhesive H. The outer diameter of the sleeve itself has a size that allows the sleeve 8a to be loosely fitted into the mounting hole 8b of the moving frame 8.

In order to perform the above-mentioned bonding, first, the convex fitting portions 7k of the first moving frame 7 formed concentrically with the optical axis, respectively.
And the concave fitting portion 8d of the second moving frame 8 are fitted. At this time, the rod 7e is inserted into the notch 8c and the rod 8e.
f is inserted into the mounting hole 8b with the sleeve 8a fitted. Then, the adhesive H flows into the gap between the sleeve 8a and the hole 8b to perform the bonding. In this way, the second moving frame 8 and the third lens group 22 are correctly and concentrically mounted around the optical axis, and do not rotate and are parallel to the optical axis direction.
In addition, the slide can be made to slide forward and backward without play. It is assumed that a compression spring 18 for removing play of both frames is inserted into a rod 7f between the second moving frame 8 and the first moving frame 7.

The second moving frame 8 is provided with two third group rods 8h and a sub rod 8k for supporting another moving frame 9 to be described later slidably in the optical axis O direction. ing. The sub rod 8k is implanted and fixed to the second moving frame 8 in a state parallel to the optical axis O. Hole 8r to be planted
Is drilled with high precision such as hole diameter and parallelism by machining or molding. Then, the rod 8k is press-fitted into the hole 8r and implanted. The sub rod 8k and the rod 8
h is disposed substantially opposite to the optical axis O (see FIG. 6). On the other hand, the rod 8h is supported by the second moving frame 8 and the arm 8e provided on the second moving frame 8 as shown in FIG. 5, but the mounting holes 8g and 8f are set in a state of loosely fitting with the rod 8h. The fixing is performed by bonding. Prior to the bonding, a sleeve 9c that is loosely fitted to another moving frame 9 is bonded and fixed.

That is, a sleeve 9c which is loosely fitted in a through hole 9b provided in a sliding arm portion 9a of the moving frame 9 is inserted, and a sleeve is attached to the optical axis of the frame 9 using a mechanical jig. 9c is held in parallel. In that state, adhesive H
Thereby, the sleeve 9c is fixed to the hole 9b. And
The rod 8h is inserted into the sleeve 9c, penetrates it, and further inserted into the holes 8f and 8g, which are the loose fitting holes of the arm 8e. Note that an E-shaped retaining ring 8m for preventing displacement before bonding is attached to the end of the rod 8h.

Subsequently, the convex fitting portion 9g of another moving frame 9 provided concentrically with the optical axis is replaced with the concave fitting portion 8p of the second moving frame 8 similarly provided concentrically with the optical axis. To fit
At the same time, the sub rod 8k is fitted into the notch 9d of the moving frame 9. Thus, the optical axes of the moving frames 8 and 9 are made to coincide with each other, and further, the direction of the rod 8h is made to coincide with the optical axis.
The rod 8h and the holes 8g and 8f of the moving frame 8 are adhered and fixed with an adhesive H. The third and fourth group lenses 22, 23 held by the moving frames 8, 9 are attached concentrically to the optical axis O and can be moved in parallel.

A slide pin 8j fitted in a cam groove 4a provided in the inner zoom ring 4 is fixed to the pin mounting portion 8s of the second moving frame 8 by a screw 8i. The movable frame 8 is moved by the optical axis O
You can move forward and backward in the direction.

An aperture unit 13 is mounted on the surface of the second moving frame 8 on the subject side. Then, by the charge lever 25 pivotally attached to the fixed frame 1,
An aperture operation of the aperture unit 13 is performed via the charged lever 13a. Since the charged lever 13a is a member elongated in the optical axis direction, the engagement with the charging lever 25 is not released even if the moving frame 8 moves in the optical axis direction. Since the aperture unit 13 has a built-in photo interrupter and an electromagnet device for adjusting the aperture, it must be electrically connected to the camera. Therefore, the unit 13 is provided with a diaphragm connection flexible substrate 13b.

The other moving frame 9 holds the fourth group lens 23, and as described above, the second moving frame 8
Are slidably supported in the optical axis direction by the two rods 8h and 8k. The rod 8h is supported via a sleeve 9c. A sliding pin 9f fitted into a cam groove 4b provided on the inner zoom ring 4 is fixed to the sliding arm 9a of the other moving frame 9 by a screw 9e. By the rotation, the moving frame 9 is moved forward and backward in the optical axis O direction.

The fifth lens group holding frame 10 holds the fifth lens group 24, and is mounted by first fitting its outer periphery 10a into the fitting hole 1a of the fixed frame. The axis and the optical axis O are matched. Then, the fixing portion 10b of the holding frame 10 is attached to the fixing frame 1 by screws or the like for positioning in the optical axis direction.

The zoom encoder section detects a rotation angle of the outer zoom ring 5 or the inner zoom ring 4 around the optical axis, and as shown in FIG.
A contact piece 13d fixed to the contact piece base 13 and sliding on the conductive pattern of the encoder board 14;
4 and a metal plate 14a for protecting the substrate 14. The contact base 13 has protrusions 13c on both side surfaces,
Edge projections 13a with a slight height in the direction of the contact piece 13d are provided on both side surfaces. Then, it is inserted into the stepped square hole 5f of the outer zoom ring 5 having the stepped portion 5k. The back surface of the edge 13b of the contact piece 13 is attached to the stepped portion 5k of the square hole 5f. The square hole 5f has such a size that the fitting surface 5e in the rotating direction of the zoom ring 5 fits into the edge 13b of the contact piece base 13 without a gap, and the length in the axial direction is the contact piece. It is larger than the width of the edge projection 13a of the base 13 plus the maximum movement amount of the zoom ring 5 in the axial direction.

The elongated hole 2d of the fixed lens frame 2 is positioned above the square hole 5f, and the width of the elongated hole 2d in the rotation direction is limited with respect to the circumferential movement of the contact piece base 13. The width in the axial direction, which is the fitting width portion 2e, is set to a width that allows the outer zoom ring 5 to be rotationally driven. I do. Therefore, the contact base 13 can move on the elongated hole 2d according to the rotation angle of the outer zoom ring 5 in the entire axial movement range of the outer zoom ring 5. Since the contact piece 13d slides on the encoder board 14 disposed along the elongated hole 2d and moves in the rotational direction, the rotation angle of zooming of the zoom ring 5 can be detected. In the encoder section, the projection 13c has a long hole 2d.
Is held down by the edge of the width portion 2e, so that the contact piece base 13 is hardly detached from the square hole 5f.

The focus drive unit 11 will be described with reference to FIGS. FIG. 8 shows the unit 1
1 is an external perspective view, and FIG. 9 is a perspective view seen from the back side. FIG. 10 is a diagram showing a YY cross section of FIG. The unit 11 constitutes a unit case 20, a focus driving motor 21, a motor output gear 21b which is an output gear fixed to a motor output shaft 21a, and a reduction gear train. Gears, sun gears, and planetary gears, the unit output gear 11a, the unit case stopper plate 31, the drive unit rotation detector, and the flexible printed circuit board 11s for electrical connection to the motor 20, PI23. It is configured. As described above, since the unit 11 is attached to the attachment surface 1h of the part where the cylindrical portion 1e of the fixed frame 1 is cut off as described above,
It is assumed that the motor 21, the reduction gear train, the case 20, the case stopper plate 31, and the like are disposed along the curvature of the cylindrical portion 1e (see FIG. 11).

The rotation detecting section comprises a slit plate 22 and a photo interrupter PI23. The PI 23 is fixed to the unit case 20 by screws via a lubricating slide plate 23a. And
The slit plate 22, which gives an input signal to the PI 23 by its rotation, is provided with a gear 2 meshing with the motor output gear 21b.
2a, and is rotatably fitted to the shaft portion 20a of the case 20. Then, the slide plate 23 acts as an axial stopper for the gear 22a.

The power transmission path by the reduction gear train between the motor output gear 21b and the unit output gear 11a is as follows. First, the motor output rotation is performed by the gear 2 having the sun gear portion 24b via the gear 22a meshing with the gear 21b.
4 is transmitted. Then, the rotation of the sun gear portion 24b is transmitted to three planetary gears 25 meshing therewith. The planetary gear 25 is axially supported by a shaft portion integrally provided on a support of the sun gear 28 with an axial stopper provided. And, it meshes with an internal gear 20 d provided on the inner wall of the case 20. Therefore, the planetary gear 25 rotates and revolves by the rotation of the sun gear portion 24b, and the sun gear 28 rotates by the rotation. Hereinafter, the rotation is transmitted to the planet gear 26 meshing with the sun gear 28 and the sun gear 29 rotated by the gear, and further to the planet gear 27 meshing with the sun gear 29 and the gear 30 rotated by the gear. Further, the gear 30 meshes with the unit output gear 11a, which is the last stage, and a rotational output reduced from the output gear 11a is obtained.

The gear 24, the gear 30, and the output gear 11a are supported by shaft portions 20b, 20c, and 20d formed integrally with the unit case 20, respectively. The three planetary gears 26 are used for the sun gears 28 and 29 without using a support shaft.
Alternatively, the shaft 27 is held at the axial center position by the engagement of 27. Also,
The axial direction is held and rotated by abutting each end face. The gears 30 and 11a are connected to case 2
A unit case stopper plate 31 for positioning and holding the unit case 0 is mounted. The case stopper plate 31 is mounted on the case by engaging the two locking claws 31b with the seat portion of the mounting hole 20e of the case 20 using elasticity.

As shown in FIGS. 2 and 10, the unit 11 is mounted on the lens barrel by bringing the case stopper plate 31 into contact with the mounting surface 1h of the fixing frame 1 and fixing the positioning dowel 31a. The unit 11 is inserted into the hole of the frame 1 and screwed into the mounting screw portion 20e to fix the unit 11 to the lens barrel. Then, the internal gear 3e of the focus ring 3, which is a driven member rotatably supported by the fixed frame 1, is brought into mesh with the unit output gear 11a, and the focus drive is enabled. The output shaft 21a to which the motor output gear 21b of the motor 21 is fixed extends in the M direction parallel to the optical axis direction, and the transmission path of the series of reduction gear trains meshing with the gear 21b is as described above. It is transmitted in the N direction opposite to the M direction. Then, the rotation output is taken out from the unit output gear 11a located on the mounting surface side.

As shown in FIGS. 8 and 9, the printed circuit board 11s for electric connection has guide pieces 20g, 2g in which the board portion 11s connected to the PI 23 is integral with the case 20.
0h and 20i. The substrate 11
The L-shaped portion 11t at the tip of s is used to prevent the guide piece 20i from coming off (see FIG. 8).

FIG. 12 is a sectional view taken along line XX of FIG.
FIG. 3 shows a vertical cross section of the mounted state of the unit 11,
On the inner diameter side of the curvature of the unit case 20 facing the optical path side, a light-shielding surface 20f having a triangular groove cross section with a small pitch is provided to shield unnecessary light outside the light beam L. Also, the printed circuit board 1
1s is bent in an S-shape and guided to the rear side of the fixed frame 1.

The zooming, focusing and collapsing operations of the zoom lens barrel constructed as described above according to this embodiment will be described. In the following description, the direction of rotation is indicated by the direction of rotation viewed from the subject side.
FIG. 3 shows the lens barrel collapsed state of the lens barrel, in which the first group frame 6 and the first moving frame 7 are collapsed, and the second group main rod 7e projects behind the fixed frame. Has become. First, the zooming operation from this state to the long focal length side will be described.

FIG. 13 shows the extended position between the wide end and the telephoto end of each lens unit. The first group is moved to the extended position by the zoom drive unit 12 based on a zoom instruction from a system controller (not shown). Move the fourth lens group. That is, the inner zoom ring 4 is rotated clockwise through the output gear 12a of the drive unit 12. With the rotation, the sliding pins 8j and 9f are
Among the grooves 4a and 4b, the grooves 4g and 4h in the collapsed area are located in the grooves 4i and 4j in the zoom area (see FIG. 14). Then, the second moving frame 8 to which the pins are fixed and the other moving frame 9 move, and the third and fourth lens units 22 and
23 is extended to each zoom position. On the other hand, the outer zoom ring 5 also rotates in the same direction via the roller 4f supported by the inner zoom ring 4. Due to the rotation, the rollers 6b and 7j are moved from the grooves 5j and 5g in the collapsed area to the grooves 5i and 5h in the zoom area among the cam grooves 5c and 5d (FIG. 15).
(A)). At the same time, since the rollers 6b and 7j are also fitted in the rectilinear grooves 2b and 2c of the fixed lens frame 2, the rollers 6b and 7j move straight in the direction of the subject. In the straight groove 2c, the straight groove 2i in the collapsed area is shifted from the straight groove 2c in the zoom area.
h. Further, since the sliding pin 3d, which is not moved during zoom driving, is fitted into the focus cam groove 5b of the outer zoom ring 5, the outer zoom ring 5 itself is focused by the action of the cam in the direction toward the subject. Just move. Therefore, the moving amount of the first group frame 6 or the first moving frame 7 to which the rollers 6b and 7j are directly or indirectly fixed by zooming is driven by the cam grooves 5c and 5d of the outer zoom ring 5. The movement is the sum of the movement amount and the focus correction amount driven by the focus cam groove 5b. Although the description of the zoom movement amount has been described in the case of the zoom drive to the long focal length side, the zoom drive to the short focal length side can be performed by driving the inner zoom ring in a counterclockwise direction. Is an operation in the direction opposite to the above-described zoom drive.

The rotation of the outer zoom ring 5 is detected by the zoom encoder unit in the detection of the zoom state accompanying the above-mentioned zoom drive. The operation thereof will be described with reference to FIGS. The contact piece 1 in which the conductive pattern on the attached encoder board 14 is supported by the contact piece base 13
3d is brought into sliding contact to extract a coded signal relating to the zoom position. The contact piece base 13 is inserted into the square hole 5f of the outer zoom ring 5 in the circumferential direction only in the fitted state as described above, and further, the axial direction is inserted into the width portion 2e of the elongated hole 2d of the fixed lens frame 2. Since they are fitted, the contact piece 13d slides on the conduction pattern with the rotation of the zoom ring 5. The zoom ring 5 also moves in the axial direction. In that case,
Since the width of the square hole 5f in the axial direction is larger than that of the contact piece base 13, the contact piece base 13 has an edge protrusion 13a formed by the fixed lens frame 2.
Is guided by the width portion 2e of the long hole 2d, and the contact piece 13d slides on the encoder board 14 to output a zoom position detection signal.

Next, the focusing operation will be described in the case of focusing from a state corresponding to the ∞ distance (infinity distance) of the subject to a predetermined subject distance. The focus drive unit 11 is driven based on a focusing instruction from the system controller, and the focus ring 3 is rotated counterclockwise via the unit output gear 11a. With the rotation, the focus cam groove 5b of the outer zoom ring 5 is moved to the sliding pin 3d of the focus ring 3.
Slides, so that the zoom ring 5 moves to the subject side.
In this case, since the inner zoom ring 4 is in a stationary state, the outer zoom ring 5 moves straight. And the rollers 6b, 7j
Move the first group frame 6 or the first moving frame 7 via
First group lens 20 and second group lens 2 as focusing lens groups
1 is extended toward the subject. Note that the focusing operation from a short distance to a long distance of the subject is performed by driving the focus ring 3 in a direction opposite to the above.

Next, the retracting operation of the lens barrel at the end of photographing in the zoom lens barrel according to the present embodiment will be described with reference to FIGS.
This will be described with reference to FIGS. First, the focus drive unit 11 is driven, the focus ring 3 is rotated clockwise, and the first and second lens units are retracted toward the camera body to the infinity in-focus position.

Subsequently, the zoom drive unit 12 is driven to rotate the inner zoom ring 4 in a counterclockwise direction. The rotation angle is further rotated counterclockwise than the phase of the zooming short focus state. Rotate to phase. as a result,
The sliding pins 8j and 9f fitted in the cam grooves 4a and 4b of the inner zoom ring 4 come to be located in the cam grooves 4g and 4h which are collapsed areas.

At the same time, the outer zoom ring 5 also rotates by the same rotation angle as the zoom ring 4. Then, as shown in FIG. 15B, the rollers 6b and 7j
The cam grooves 5g and 5j are located in the collapsed areas c and 5d. Therefore, the first group frame 6 and the first moving frame 7 are retracted from the position corresponding to the ∞ distance to the retracted position further retracted toward the camera body. When the first group frame 6 retreats to the retracted position as described above, the first moving frame 7 does not move to a position outside the normal zoom range, unless the first group lens holding frame 6c or the first group lens is moved. Interference with 20 or the like or clogging occurs. Therefore, the rectilinear groove 2i and the cam groove 5g in the collapsed area are loosely fitted to the roller 7j fitted therein, so that the above-described interference is avoided and the collapse is performed reliably.

As described above, according to the lens barrel of the present invention, it is possible to prevent the cam follower and the cam groove from interfering with each other when the lens barrel is collapsed due to a manufacturing error, thereby preventing the loss of the driving force and shortening or shortening the driving force. Unnecessary energy consumption during collapsing can be suppressed.

[0048]

As described above, according to the present invention, it is possible to provide a lens barrel which has a simple structure and can reduce the length of the lens barrel or suppress the energy loss at the time of collapsing.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a zoom lens barrel to which an encoder device according to an embodiment of the present invention is applied,

FIG. 2 is an exploded perspective view of a zoom lens barrel to which the encoder device according to the embodiment of the present invention is applied;

FIG. 3 is a longitudinal sectional view of the lens barrel of the zoom lens barrel shown in FIGS. 1 and 2 in a collapsed state;

FIG. 4 is a view taken in the direction of arrow A in FIG. 1;

FIG. 5 is a view showing a rod fixing state of each lens holding frame of the zoom lens barrel shown in FIGS. 1 and 2;

FIG. 6 is a sectional view taken along the line BB in FIG. 1;

FIG. 7 is a development view of a zoom encoder device of a zoom lens barrel showing an embodiment of the present invention;

FIG. 8 is a perspective view of a focus drive unit mounted on the zoom lens barrel of FIG. 1;

FIG. 9 is a perspective view of a focus drive unit mounted on the zoom lens barrel of FIG. 1;

FIG. 10 is a sectional view taken along line YY in FIG. 8;

FIG. 11 is a diagram showing a state in which the focus drive unit of the zoom lens barrel shown in FIG. 1 is mounted on a fixed frame.

FIG. 12 is a sectional view taken along the line XX in FIG. 11;

FIG. 13 is a view showing the extending position of each lens group in zoom driving of the zoom lens barrel in FIG. 3;

14 is a development view of a cam groove of an inner zoom ring of the zoom lens barrel of FIG. 2;

FIG. 15A is a view showing the zoom lens barrel of FIG. 2;
FIG. 3B is a developed view of the outer zoom ring at the time of a zoom operation, and FIG. 2B is a developed view of the zoom lens barrel shown in FIG. 1 when the outer zoom ring is collapsed.

[Explanation of symbols]

 2 Fixed lens frame 2c Straight groove (first groove means) 2h Straight groove (groove portion in zoom region) 2i Straight groove (groove portion in collapsible region) 5 Outer zoom ring 5d Cam groove (second groove means) 5h Cam groove (cam portion in zoom region) 5g Cam groove (cam portion in collapsible region) 7 …… Moving frame 7j ……… Roller (cam follower)

Claims (1)

(57) [Claims] 1. A lens barrel that operates zooming and precipitation cylinder, a movable frame that moves in the optical axis direction during the zooming and the precipitation cylinder operation of the lens barrel, a cam follower provided on the movable frame, the Fits and slides with the above cam follower for zooming
And a groove as a zoom area for moving the moving frame.
Formed continuously from the groove and having a wider groove width than the groove
Fitted and slid in contact with the cam follower for the collapse operation
And a groove as a collapsible area for moving the moving frame.
A lens barrel comprising: a cam groove ;