JP2863605B2 - Zoom lens barrel - Google Patents

Description

The present invention relates to a zoom lens barrel, and more particularly, to a zoom lens barrel having a fixed frame and a movable lens holding frame, and rotating or moving the movable frame to zoom. Alternatively, the present invention relates to a zoom lens barrel that performs focusing.

[Prior Art] In recent years, many proposals have been made regarding a lens frame driving mechanism of a zoom lens barrel in order to cope with a reduction in size, weight, accuracy, and cost reduction of a camera. For example,
The zoom lens barrel disclosed in Japanese Patent Application Laid-Open No. 57-116309 has a structure in which a cam ring for zoom is integrated into two, and these are turned integrally when zooming, and one of them can be moved back and forth during focusing. It has. The zoom lens barrel disclosed in Japanese Patent Application Laid-Open No. Sho 60-43619 has a structure in which zooming and focus adjustment can be performed with a single cam ring.

[Problems to be Solved by the Invention] However, in the zoom lens barrel disclosed in the above-mentioned JP-A-57-116309, when the number of lens groups is increased, the cam ring must be extended in the optical axis direction. However, there was a problem that the total length of the lens barrel was increased. Also, JP-A-60-43
The zoom lens barrel disclosed in Japanese Patent No. 619 requires a straight groove in the cam of the cam ring relating to the lens group other than the lens group for focus adjustment, and the linear groove increases accordingly as the number of lens groups increases. I will. As a result, there is a problem that the cam cannot be arranged on the cam ring.

SUMMARY OF THE INVENTION An object of the present invention is to provide a structure in which a cam ring of a zoom lens barrel is separated into two bodies, a lens barrel that rotates and advances and retreats during zooming, and one of which moves straight when focusing, thereby achieving high magnification zooming. An object of the present invention is to provide a zoom lens barrel which is made possible, can shorten the entire length of the lens barrel, has a simple structure, and is advantageous in cost.

Means and Action for Solving the Problems A zoom lens barrel according to the present invention is provided rotatably with respect to a fixed frame, and is rotatably driven during a zooming operation.
And a second frame provided around the optical axis with respect to the first frame so as to be rotatable and advanceable / retractable with respect to the fixed frame inside or outside the first frame. First cam means for connecting the first frame to a lens group frame other than the lens group frame; and second cam means for connecting the focusing lens group frame to the second frame.
The first frame and the second frame are rotated around the optical axis to move all the lens groups forward and backward in the optical axis direction to change the focal length. The focusing operation is performed by moving only the focusing lens group forward and backward in the optical axis direction by moving forward and backward in the optical axis direction.

[Embodiment] Hereinafter, the present invention will be described based on the illustrated embodiment.

1 and 2 are an exploded perspective view and a longitudinal sectional view of a zoom lens barrel in a collapsed state, respectively, showing an embodiment of the present invention. This zoom lens barrel enables zooming, focusing and collapsing operations. The main components of the zoom lens barrel are a fixed frame 1, a fixed lens frame 2 fixed to the fixed frame 1, and a focus ring 3.
, An inner zoom ring 4 as a first frame, an outer zoom ring 5 as a second frame, and a first group frame 6 as a focusing lens group frame.
Similarly, the second group lens holding frame 7 which is a focusing lens group frame, the third and fourth group lens holding frames 8 and 9 which are lens group frames other than the focusing lens, and the fifth group lens holding frame 10 And the first, second, third, fourth and fifth group lenses 20, 21, 22, 23, and 24 (see FIG. 2) held directly or indirectly by the frames, a focus drive unit 11, and a zoom Drive unit 12, aperture unit
13 and a zoom encoder unit.
The lens groups 20 to 24 are shown in FIGS. 1 (A) and 1 (B).
Although not shown in FIG. 2, they are respectively shown in the sectional views of FIG.

The fixed frame 1 is fixed to a mirror box 16 of the camera body via spacers 14 and 15. The spacer 1
Mirror box 16 as shown in FIG.
Mirror frame 17 holding the movable reflection mirror 19 attached to
And the distance between the frame 1 and the fixed frame 1 is adjusted. 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. Furthermore, a cylindrical portion 1e for supporting the inner zoom ring 4 so as to be rotatable around the optical axis O is provided, and a sliding pin 1g is screwed with a screw 1f to restrict the movement of the inner zoom ring 4 in the optical axis direction. It is fixed on the cylindrical portion 1e.

Further, the fixed frame 1 is provided with a fitting hole 1b and a fitting elongated hole 1c for supporting the second group main rod 7e and the second group sub rod 7f slidably 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. Furthermore, a charge lever 25 for operating the aperture unit 13
Is also pivotally attached to the fixed frame 1 through the shaft hole 25a.

The fixed lens frame 2 has a cylindrical shape, and is fixed to the fitting portion 1d of the fixed frame 1 with its inner peripheral portion 2a fitted. In the cylindrical portion, along the optical axis O, the guide rectilinear grooves 2b and 2c of the first group frame 6 and the second group lens holding frame 7, and along the circumferential direction of the inner circumference on the fixed frame 1 side. A bottomed inner circumferential groove 2g for regulating the axial position of the focus ring 3 also has an elongated hole 2d for regulating the axial position of the contact base 13 along the circumferential direction of the cylindrical portion opposite to the fixed frame side. Are provided respectively. Note that, as shown in the development of FIG. 14, the rectilinear groove 2c has a groove 2h in a zoom region having a width equal to the outer diameter of the roller 7j to be fitted therein, and a width larger than the outer diameter. And the groove 2i of the collapsible region. 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 has an internal gear 3e which meshes with the output gear 11a of the focus drive unit 11. Is provided. A sliding pin 3b is fixed to the pin fixing portion on the outer peripheral portion by a screw 3a. The sliding 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. Further, a slide pin 3d for moving the zoom ring 5 in the optical axis direction is fixed to a pin fixing portion 3g on the protrusion that is loosely fitted on the inner periphery of the outer zoom ring 5 by a screw 3c. The slide 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 ring 4d provided in the inner peripheral portion thereof. 1g of 1 sliding pin
And the movement of the zoom ring 4 in the optical axis direction is prohibited. An output gear 12a of the zoom drive unit 12 driven based on a zoom control signal is provided on the inner peripheral portion.
There is provided an internal gear 4c that meshes with.

The zoom ring 4 is a cam groove which is a first cam means for driving the third and fourth lens holding frames 8 and 9 for zooming.
4a and 4b are provided. Then, sliding pins 8j, 9f fixed to the third and fourth lens holding frames 8, 9 are fitted into these cam grooves 4a, 4b, and the cam shape is shown in the developed view of FIG. As shown, each of the cam grooves 4g and 4h in the retracted area corresponding to the lens barrel retracted state having no displacement in the optical axis direction, and the cam grooves 4i and 4j in the zoom area having the zoom displacement in the optical axis direction are formed. Have been. A roller 4f, which is a connecting member fitted into the rectilinear groove 5a of the outer zoom ring 5, has a pin 4e on its outer peripheral portion.
It is rotatably supported by.

The outer zoom ring 5 is a cylindrical member, and the outer peripheral portion and the inner peripheral portion thereof are fixed to the fixed lens frame 2 and the first group frame 6.
Are rotatably or slidably fitted respectively. A straight groove 5a is provided along the optical axis O, and the inner zoom ring 4 is driven to rotate according to the zoom amount via a roller 4f fitted in the groove. Further, the zoom ring 5 is provided with a focus cam groove 5b corresponding to the amount of feeding out, and the slide pin 3d of the focus ring 3 is provided.
Is inserted, the zoom ring 5 is moved straight in the optical axis direction by the focusing amount.

Further, the zoom ring 5 is provided with cam grooves 5c and 5d as second cam means. And those cam grooves 5c,
The first and second group rollers 6b and 7j supported by the first group frame 6 and the second group lens holding frame 7 are fitted into 5d. Therefore,
The first group frame 6 and the second group lens holding frame 7 are displaced in the optical axis O direction according to the rotation of the main zoom ring 5 by zooming or the axial movement by focusing. The cam grooves 5c and 5d are used to retract the cam units 5i and 5h in the zoom region for providing a driving position during focusing and zooming, and the first group frame 6 or the second group lens holding frame 7 when the camera is not used. The cam portions 5j and 5g in the collapsible region for moving to the position, that is, retracting to the camera body side. In addition, the cam part 5g
The groove width is formed to be larger than the outer diameter of the roller 7j to be inserted, so that interference between the lens groups does not occur at the time of the retraction (see FIG. 14).

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

The first group frame 6 is to which the first group lens holding frame 6c is screwed, and has a cylindrical shape. The outer peripheral portion is slidably fitted into the outer zoom ring 5. And
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 a straight groove of the cam groove 5c and the fixed lens frame 2.
2b is also inserted. 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. A concave portion 6e is formed on the inner periphery of the first group frame 6 to form a thin portion along the axial direction. 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 interval is adjusted by the spacer 6d, and is supported by the first group frame 6.

The second group lens holding frame 7 holds the second group lens frame 7a to which the second group lens 21 is attached. As shown in FIG. 3, two U-shaped notches 7b are provided on the outer surface of the rod so as to oppose the optical axis of the lens frame in order to fix and support the rod, which is a rod-shaped guide member. ing. 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 7e or a second group
One end of the group sub rod 7f is inserted, and the rod 7
e and 7f are pressed and fixed. Then, since each rod is pressed by the slope of the fixing piece 7, the rods 7e and 7f are
Each of the cutouts 7b comes into contact with the two sides 7c of the cutout 7b, and as a result, is mounted in parallel with the optical axis of the lens frame.

And the other end of the mounted rods 7e, 7f are:
The fixing frame 1 is slidably inserted into the fitting hole 1b and the fitting long hole 1c. Accordingly, the second lens group to which the second group lens 21 is attached
The group lens holding frame 7 can slide forward and backward along the optical axis O without rotating. In addition, a third group lens holding frame 8 of another lens holding frame slidably supported and guided by the rods is inserted into an intermediate portion of the rods 7e and 7f.

The main holding frame 7 is for driving in the axial direction,
A second group drive plate 7h extending in the optical axis direction is fixed via screws. A roller is attached to the tip of the drive plate 7h.
7j is rotatably mounted 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. Therefore, with the rotation and axial movement of the outer zoom ring 5,
The second group lens holding frame 7 moves in the direction of the optical axis O via the driving plate 7h, and the second group lens 21 is similarly moved. The driving plate 7h is located in a space of the concave portion 6e provided in the first group frame 6 due to its arrangement.

The third lens group holding frame 8 holds the third lens group 22. The third lens group holding frame 8 has a second group main rod 7e and a sub rod fixed to a pair of optical axes on the second group lens frame 7. It is slidably supported in the optical axis direction by 7f. That is,
The rod 7e is fitted into the notch 8c of the third lens group holding frame 8, while the sub-rod 7f is inserted through the sleeve 8a into which the sub-rod 7f fits as shown in the mounting state diagram of FIG. Support 8 The sleeve 8a is fixed to the holding frame 8 with an adhesive H. The outer diameter of the sleeve itself has a size that allows it to be loosely fitted into the mounting hole 8b of the holding frame 8.

In order to perform the bonding, first, the convex fitting portion 7k of the second group lens holding frame 7 formed concentrically with the optical axis and the third
The rod 7e is inserted into the notch 8c, and the rod 8f is inserted into the mounting hole 8b with the sleeve 8a fitted to the concave fitting portion 8d of the group lens holding frame 8. .
Then, the adhesive H flows into the gap between the sleeve 8a and the hole 8b to perform bonding. In this way, the third lens group holding frame 8 and the third lens group 22 are mounted concentrically with the optical axis center correctly, and can slide forward and backward in parallel with the optical axis direction without rotation without play. State. It is assumed that a compression spring 18 is inserted between the third lens group holding frame 8 and the second lens group holding frame 7 in a rod 7f between the third lens group holding frame 8 and the second lens group holding frame 7 to remove backlash of both frames.

Further, two third group rods 8h and sub rods 8k for supporting a fourth group lens holding frame 9 to be described later slidably in the optical axis O direction are attached to the third group lens holding frame 8. ing. The sub rod 8k is implanted and fixed to the third lens group holding frame 8 in a state parallel to the optical axis O. The hole to be planted
8r 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 8h are disposed so as to be substantially opposed to the optical axis O (see FIG. 5). On the other hand, as shown in FIG. 4, the rod 8h has a third lens group holding frame 8 and an arm 8e provided on the frame.
The mounting holes 8g and 8f are loosely fitted to the rod 8h, and the fixing is performed by bonding. In addition,
Prior to the bonding, a sleeve 9c that is loosely fitted to the fourth group lens holding frame 9 is bonded and fixed.

That is, the through hole 9b provided in the sliding arm 9a of the holding frame 9
Insert the sleeve 9c that loosely fits into the
The sleeve 9 is held such that the inner diameter of the sleeve 9 is parallel to the optical axis of the frame 9. In this state, the sleeve 9c is fixed to the hole 9b by the adhesive H. Then, put the rod 8h on the sleeve
9c, penetrates, and further, a hole that is a loose fitting hole of the arm 8e.
Insert 8f and hole 8g. 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 the fourth group lens holding frame 9 provided concentrically with the optical axis is replaced with the concave fitting portion 8p of the second group lens holding 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 holding frame 9. In this manner, the optical axes of the holding frames 8 and 9 are made to coincide with each other, and further, the direction of the rod 8h is made to coincide, and the rod 8h and the holes 8g and 8f of the holding frame 8 are adhered and fixed with the adhesive H. Third and fourth group lenses 22, 2 held by the holding frames 8, 9
3 is mounted concentrically on the optical axis O and can be moved in parallel.

A sliding pin fitted into a cam groove 4a provided on the inner zoom ring 4 is provided on the pin mounting portion 8s of the third lens group holding frame 8.
8j is fixed by the screw 8i, so that the zoom ring 4
By the rotation of, the holding frame 8 is moved forward and backward in the direction of the optical axis O.

An aperture unit 13 is mounted on the subject-side surface of the third lens group holding frame 8. Then, the aperture operation of the aperture unit 13 is performed by the charge lever 25 pivotally attached to the fixed frame 1 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 holding frame 8 moves in the optical axis direction. Further, 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 side. Therefore, the unit 13 is provided with a diaphragm connection flexible substrate 13b.

The fourth lens group holding frame 9 holds the fourth lens group 23, and is slidable in the optical axis direction by the two rods 8h and 8k of the third lens group holding frame 8 as described above. It is supported by. The rod 8h is supported via a sleeve 9c. A sliding pin 9f fitted into a cam groove 4b provided in the inner zoom ring 4 is fixed to the sliding arm 9a of the fourth lens group holding frame 9 by a screw 9e. 4, the holding frame 9 moves the optical axis O
You can move forward and backward in the direction.

The fifth lens group holding frame 10 holds the fifth lens group 24. First, the outer periphery 10a is fitted into the fitting hole 1a of the fixed frame, and the fifth lens group 24 is attached to the lens optical axis. Align the axis O. 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 unit detects the rotation angle of the outer zoom ring 5 or the inner zoom ring 4 around the optical axis, and as shown in FIG. , And includes a contact piece 13d that slides on the conductive pattern of the encoder substrate 14, an encoder substrate 14, and a metal plate 14a that protects the substrate 14. Above contact table 13
Has projections 13c on both sides and edge projections 13a with a slight height in the direction of the contact piece 13d on both sides. The outer zoom ring 5 is inserted into the stepped square hole 5f having the stepped portion 5k, and is attached to the stepped portion 5k of the square hole 5f such that the back surface of the edge 13b of the contact piece base 13 is in contact with the stepped portion. The square hole 5f has such a size that the fitting surface 5e in the rotating direction of the zoom ring 5 fits with the edge 13b of the contact piece base 13 without any gap, and the axial length is the contact piece. It is larger than the width obtained by adding the maximum movement amount of the zoom ring 5 in the axial direction to the width dimension of the edge projection 13a of the base 13.

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 by the outer zoom ring with respect to the circumferential movement of the contact base 13. The width in the axial direction, which is the fitting width portion 2e, is a fitting dimension in which the edge projection 13a or both side surfaces of the contact piece base 13 can slide. Accordingly, the segment table 13 can move on the elongated hole 2d in accordance with the rotation angle of the contact piece table 13 throughout the axial movement of the outer zoom ring 5. And
Since the contact piece 13d slides on the encoder board 14 disposed along the elongated hole 2d and moves in the rotation direction, the rotation angle of the zoom ring 5 during zooming can be detected. Note that, in the encoder section, the contact piece 13 is
Are pressed by the edge of the width portion 2e of the elongated hole 2d, so that the contact base 13 is hard to come off from the square hole 5f.

The focus drive unit 11 will be described with reference to FIGS. FIG. 7 is a perspective view of the external appearance of the unit 11, and FIG. 8 is a perspective view seen from the back side.
FIG. 9 is a view showing a cross section taken along line YY of FIG. The unit 11 includes a unit case 20,
A focus drive motor 21, a motor output gear 21b, which is an output gear fixed to the motor output shaft 21a, and a reduction gear train, wherein the gear meshes with the gear 21b, a sun gear, a planetary gear, It is composed of a unit output gear 11a, a unit case stopper plate 31, a drive unit rotation detector, and a flexible printed circuit board 11s for electrical connection to the motor 20, PI23. As described above, since the unit 11 is mounted on the mounting surface 1h of the portion where the cylindrical portion 1e of the fixed frame 1 is cut out as described above, the motor 21 and the reduction gear train, and the case 20 or the case stopper The plate 31 and the like are arranged along the curvature of the cylindrical portion 1e (see FIG. 10).

The rotation detecting unit includes 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. The slit plate 22 that gives an input signal to the PI 23 by its rotation is formed integrally with a gear 22a that meshes with the motor output gear 21b, and is rotatably fitted into the shaft portion 20a of the case 20. And gear 22a
The above-mentioned slide plate 23 acts as a stopper in the axial direction.

In the power transmission path by the reduction gear train between the motor output gear 21b and the unit output gear 11a, first, the motor output rotation is transmitted to the gear 24 having the sun gear portion 24b via the gear 22a meshing with the gear 21b. . Then, the rotation of the sun gear portion 24b is transmitted to three planetary gears 25 meshing with the sun gear portion 24b. The planetary gear 25 is axially supported by a shaft part integrally provided on a support of the sun gear 28 with an axial stopper provided. And case 20
Is meshed with an internal gear 20d provided on the inner wall. Therefore, the planetary gear 25 rotates and revolves by rotation of the sun gear portion 24b, and the sun gear 28 rotates by the rotation. Hereinafter, the rotation is transmitted to the planetary gear 26 meshing with the sun gear 28 and the sun gear 29 rotated by the gear, and further to the planetary 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 the output gear 11a
A more reduced rotation output is obtained.

The gear 24, the gear 30, and the output gear 11a
Are rotatably supported by shaft portions 20b, 20c, 20d formed integrally with the unit case 20, respectively. And the sun gear 28,29
Is held at the axial center position by engagement of the respective three planetary gears 26 or 27 without using a support shaft. The axial direction is held and rotated by abutting each end face. A unit case stopper plate 31 for positioning and holding the gears 30 and 11a in the case 20 is mounted. To attach the case stopper plate 31 to the case, the two locking claws 31b are attached to the mounting hole 20e of the case 20.
Attach it to the seat part using elasticity.

As shown in FIGS. 1 and 9, 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 fixed frame 1 and positioning the dowels 31a on the corresponding fixed frame 1. The unit 11 is fixed to the lens barrel by inserting it into the hole and screwing a screw to the mounting screw portion 20e. An internal gear of a focus ring 3 which is a driven member rotatably supported by the fixed frame 1.
3e is engaged 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. 7 and 8, the printed circuit board for electrical connection 11s is disposed such that the board portion 11s connected to the PI 23 is hung on guide pieces 20g, 20h, and 20i that are integral with the case 20. . The L-shaped portion 11t at the tip of the substrate 11s is a guide piece 20.
It is used to prevent slippage from i (see FIG. 7).

FIG. 11 is a sectional view taken along line XX of FIG.
This shows a longitudinal section in the mounted state, but has a light-shielding surface 20f of a small pitch triangular groove cross section on the inner diameter side of the curvature of the unit case 20 facing the optical path side, so that unnecessary light outside the light beam L is It is shaded. The printed circuit board 11s 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 configured as described above according to the present 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. 2 shows the lens barrel collapsed state of the lens barrel.
The group lens holding frame 7 is collapsed, and the second group main rod 7e is projected behind the fixed frame. First, the zooming operation from this state to the long focal length side will be described.

FIG. 12 shows the extended position between the wide end and the tele end of each lens group, and is controlled by the zoom drive unit 12 based on a zoom instruction from a system controller (not shown).
The first to fourth lens units are moved to the extended position. 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 moved to the collapsed groove of the cam grooves 4a and 4b.
From 4g and 4h, they are located in the grooves 4i and 4j of the zoom area (see FIG. 13). Then, the third and fourth group lens frames 8, 9 to which the pins are fixed move, and the third and fourth group lenses 22, 23 are extended to the respective zoom positions. 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. By the rotation, the rollers 6b and 7j are positioned from the grooves 5j and 5g in the collapsed area to the grooves 5i and 5h in the zoom area of the cam grooves 5c and 5d (see FIG. 14A). 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 and move toward the subject. In the straight groove 2c, a transition is made from the groove 2i in the collapsed area to the straight groove 2h in the zoom area. Further, since the sliding pin 3d, which is not moved during zoom driving, is fitted in the focus cam groove 5b of the outer zoom ring 5, the outer zoom ring 5 itself is moved in the direction toward the subject by the action of this cam. Just move. Accordingly, the moving amount of the first group frame 6 or the second group lens holding frame 7 to which the rollers 6b and 7j are directly or indirectly fixed by zooming is determined by the outer zoom ring 5
The movement amount is the sum of the movement amount driven by the cam grooves 5c and 5d 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 associated with the above-described zoom drive. The operation will be described with reference to FIGS.
The coded signal relating to the zoom position is extracted by bringing the conductive pattern on the encoder substrate 14 attached to the fixed lens frame 2 into sliding contact with the contact piece 13d supported by the contact piece base 13.
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 this case, since the axial hole width of the square hole 5f is larger than the contact base 13, the contact base 13 has an edge portion. Protrusion
13a is guided by the width portion 2e of the elongated hole 2d of the fixed lens frame 2, and the contact piece 13d
Can slide on the encoder board 14 to output a zoom position detection signal.

Next, as for the focusing operation, an operation in the case of focusing from a state corresponding to the ∞ distance (infinity distance) of the subject to a predetermined subject distance will be described. 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
As the sliding pin 3d of the focus ring 3 slides, 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. Then, the first group frame 6 or the second group lens holding frame 7 is moved via the rollers 6b and 7j, and the first lens group 20 and the second lens group 21, which are focusing lens groups, are 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, with reference to FIGS. 1 and 4 (A), the lens barrel retracting operation of the zoom lens barrel according to the present embodiment at the end of shooting.
This will be described with reference to FIG. 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 counterclockwise. The rotation angle is further rotated from the phase in the zooming short focus state to the lens barrel retracted phase rotated further counterclockwise. Move. As a result, the inner zoom ring 4
The sliding pins 8j, 9f fitted in the cam grooves 4a, 4b are located in the cam grooves 4g, 4h, which are the 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. 14 (B), the rollers 6b, 7j are positioned in the cam grooves 5g, 5j in the collapsed area of the cam grooves 5c, 5d of the zoom ring 5. Therefore, the first group frame
6. The second lens group holding frame 7 is retracted further to the collapsed position where it is retracted further toward the camera body than the position corresponding to the ∞ distance. When the first group frame 6 retreats to the retracted position as described above, the second group lens holding frame 7 does not move to a position outside the normal zoom range.
And the first group lens 20 and the like, or clogging occurs. Therefore, the straight groove 2i and the cam groove 5g in the collapsed area are
The roller 7j is loosely fitted to the roller 7j to be inserted therein, so that the above-mentioned interference is prevented from occurring, and the collapsible lens can be reliably carried out.

Next, a modified example of the structure for fixing the main rod 7e and the sub rod 7f for supporting the frame to the second group lens holding frame 7 will be described with reference to FIGS. In this modification, a U-shaped notch for fixing the rods 7e and 7f is different from that of the above-described embodiment.

In FIG. 15, a notch 57b for holding rods 57e and 57f with good straightness is provided on the outer periphery of the second lens group holding frame 57 so as to be substantially opposed to the optical axis of the holding frame. . The notch 57b has a side contact surface 57c parallel to the optical axis and bottom contact surfaces 57k and 57m with which the rods 57e and 57f abut. The cylindrical outer diameter surfaces 57k and 57m serving as the bottom contact surfaces use cylindrical portions provided on the holding frame 7. The cylindrical outer diameter surfaces 57k and 57m are concentric with the optical axis and have the same outer diameter. The portion between the bottom contact surfaces 57k and 57m is a surface 57n that is recessed from the contact surface.

Then, each rod is fixed by inserting the rods 57e, 57f into the cutouts, positioning the inclined surfaces of the distal ends of the two fixing pieces 57d on the rods 57e, 57f, respectively, and pressing with the screws 57g. Fix it. Since the portion between the bottom contact surfaces 57k and 57m is recessed as described above, the rod 57e,
57f is more reliably brought into contact with the side contact surface 57c and the bottom contact surfaces 57k, 57m. Therefore, according to this modification, the rod supporting the lens holding frame can be fixed with high accuracy in parallel to the optical axis of the frame.

As another modified example of the fixing structure of the rods 7e and 7f, a V-shaped notch fixing groove of the above-described embodiment has a V-shaped notch fixing groove.
It is also possible to propose a device using a letter-shaped notch groove. In this modification, the V-shaped cutout groove is provided on the outer periphery of the lens holding frame so as to be substantially opposed to the optical axis, and the cutout groove is also in a state parallel to the optical axis. Then, the rods 7e and 7f are attached to the notched grooves and fixed to the holding frame with a flat fixing plate. The rod fixed in this manner is also supported in parallel with high precision with respect to the optical axis, but the V-shaped notch is more easily machined or formed, so that the degree of parallelism can be easily obtained. Fixation becomes possible.

As described above, the zoom lens barrel of the present embodiment is
The zoom ring is divided into first and second inner and outer frames, and the outer and outer zoom rings 4 and 5 are rotated or driven straight forward to change the zooming operation, that is, the focal length. Further, the outer zoom ring 5 is driven straight forward to move only the focusing lens group forward and backward to perform a focusing operation. According to this embodiment, since the inner and outer zoom rings 4 and 5 are disposed so as to overlap with each other, the total length of the lens barrel can be further reduced.

The main rod 7e and the sub-rod 7f, which are rod-shaped guide members for sliding the second group lens holding frame 7 in the zoom lens barrel of the present embodiment, are fixed by the optical axis provided with the rod on the holding frame 7. Is pressed against and fixed to a U-shaped notch 7b having two abutting surfaces parallel to. If the notched portion is formed with high precision by, in particular, machining or molding the contact surface, the rod can be fixedly supported on the holding frame more accurately than a conventional method such as press fitting. Further, since the above structure fixes the rod to the outer peripheral portion of the frame, it can be applied to a small lens frame.

Further, the fixing of the sleeve 8a in which the rod 7f for sliding support of the third lens group holding frame 8 in the present embodiment is fixed is performed by bonding. That is, in order to make the optical axes of both the second group lens holding frame 7 and the holding frame 8 coincide with each other, the two lens groups are held in a state where the concentric fitting portions are fitted to the optical axes, respectively. The fitted sleeve 8a is slidably fitted into the rod 7f fixedly supported on the holding frame 7, and in this state, the loosely fitted sleeve 8a is fixed to the holding frame 8 by bonding. Therefore, it is possible to maintain the positional accuracy of each member at the time of performing the bonding, and in particular, it is possible to assemble a higher positional accuracy between the holding frames without increasing the component accuracy or the like of each member itself. .

Further, the rod 8h, which is the guide member of the fourth lens group holding frame 9 in the zoom lens barrel of the present embodiment, is fixed to the third lens group holding frame 8 by bonding. That is, in order to make the optical axes of both frames coincide with each other, the concentric fitting portions are respectively fitted to the optical axes, and the rods 8h fitted into the holding frames 9 are loosely fitted to the holding frames 8 in a state of being fitted. Insert
In this state, the rod 8h is bonded to the holding frame 8.

Since the sleeve 8a is fixed in this manner, it is possible to maintain the positional accuracy of each member at the time of performing the bonding, and in particular, without increasing the fitting accuracy of each member, a higher distance between the holding frames. It is possible to perform positional accuracy assembly.

Further, the focus drive unit 11 of the zoom lens barrel according to the present embodiment is disposed in a part of a donut-shaped space in the barrel in order to efficiently store the focus drive unit 11, and its outer shape is a predetermined shape corresponding to the cylindrical portion of the barrel. And the motor and the reduction gear train are arranged in accordance with the curvature. Further, the output axis of the motor and the axis of the reduction gear train are arranged so as to be parallel to the optical axis O. Then, for convenience of driving the focus ring 3, the output gear 21b of the motor and the unit output gear 11a for taking out the rotation output of the drive unit are provided on the side where the internal gear 3e of the focus ring 3 of the driven part is located. Is located on the motor mounting side. Therefore, the extension direction of the motor output shaft to which the motor output gear 21b is fixed is opposite to the direction of the driven portion side, and the unit output gear
The extension direction of the shaft portion of the reduction gear train 11a is mounted in front thereof by being opposite to the extension direction,
A more efficient drive system path can be provided. The drive unit 11 configured as described above enables the storage space for the lens barrel to be efficiently used, and does not require an unnecessary increase in the diameter of the lens barrel.

[Effects of the Invention] As described above, the zoom lens barrel of the present invention changes the focal length by rotating or moving the first frame and the second frame having the respective cam means, and further, , Second
According to the present invention, since the first and second frames are disposed so as to overlap each other, the total length of the lens barrel can be further reduced. Can,
A high-power zoom lens barrel with a short overall length can be realized. In addition, a zoom lens barrel having a number of remarkable effects can be provided, for example, the structure is simplified and the cost is advantageous.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are exploded perspective views of a zoom lens barrel showing an embodiment of the present invention, respectively, and FIG. 2 is a zoom lens mirror shown in FIG. FIG. 3 is a view in the direction of arrow A in FIG. 1; FIG. 4 is a longitudinal sectional view of the barrel when the lens holding frame of the zoom lens barrel in FIG. 1 is fixed to the rod; FIG. 5, FIG. 5 is a cross-sectional view taken along the line BB of FIG. 1, FIG. 6 is a development view of a zoom encoder unit of the zoom lens barrel of FIG. 1, and FIGS. FIG. 9 is a perspective view of a focus drive unit mounted on the zoom lens barrel of FIG. 1, FIG. 9 is a sectional view taken along line YY of FIG. 7, and FIG. 10 is a focus of the zoom lens barrel of FIG. FIG. 11 is a view showing a state in which the drive unit is mounted on a fixed frame, FIG. 11 is a cross-sectional view taken along line XX of FIG. 10, and FIG. FIG. 13 is a view showing the extended position of each lens group during zoom drive of the zoom lens barrel. FIG. 13 is a development view of a cam groove of an inner zoom ring of the zoom lens barrel of FIG. 1, and FIG. Of the zoom lens barrel shown in FIG.
FIG. 14 (B) is a development view of the outer zoom ring at the time of a zoom operation, FIG.
FIG. 15 is a development view of the outer zoom ring when the lens barrel is collapsed, and FIG. 15 is a rod fixing of the second group lens holding frame of a modification of the rod fixing structure of the second lens holding frame of the zoom lens barrel of FIG. FIG. 16 is a longitudinal sectional view showing the state, and FIG. 16 is a perspective view showing the rod-fixed state of the second group lens holding frame of the modified example of FIG. 1 fixed frame 4 inner zoom ring (first frame) 5 outer zoom ring (second frame) 4f rollers (connecting members) 4a, 4b cam grooves (first cam means) 5c, 5d: cam groove (second cam means) 6: first group frame (focusing lens group frame) 7, 57: second group lens holding frame (focusing lens group frame) 8: Third group lens holding frame (lens group frame other than focusing lens group) 9... Fourth group lens holding frame (lens group frame other than focusing lens group)

Claims (1)

(57) [Claims] A first frame rotatably provided with respect to a fixed frame and rotatably driven during a zooming operation; a first frame inside or outside the first frame; A second frame integrally provided around the optical axis with respect to the first frame, and a first cam for connecting the first frame to a lens group frame other than the focusing lens group frame so as to be able to advance and retreat. And a second cam means for connecting the focusing lens group frame and the second frame. All the lenses are rotated by rotating the first frame and the second frame around the optical axis. The focal length is changed by moving the group in the optical axis direction, and the focusing operation is performed by moving only the focusing lens group in the optical axis direction by moving the second frame in the optical axis direction. Zoom lens barrel.