JP2821881B2 - Zoom lens barrel - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel used for optical equipment such as a camera for photographing, a small camera, a video camera, a copying machine, and an enlarger. 2. Description of the Related Art A zoom lens barrel includes a cam cylinder having an elongated cam hole along its periphery, and a cam floor (pin-shaped roller) protruding into the cam hole. And a movable cylinder that supports the correction lens and a correction lens. The movable cylinder is moved in the optical axis direction by rotating the cam cylinder to perform optical zooming. ing. In practice, a plurality of moving cylinders are provided inside a cam cylinder, and each of these moving cylinders often moves in conjunction with the cam cylinder. "Problems to be Solved by the Invention" FIGS. 11 and 12 are simplified diagrams showing an interlocking structure between the above-described cam cylinder and moving cylinder. In the cam cylinder 1, a cam hole 1a is formed along the circumferential direction. A cam follower which is formed in the cam barrel 1 and which is inserted into the cam bore
2a is provided. As shown in FIG. 13, the cam hole 1a of the cam cylinder 1 is formed by sequentially designing the design values of Δθ and Δl in advance within the range of θ, and the cam follower 2a extends the cylinder axis with respect to the cam wall. They are joined at the center line. For this reason, the above-described cam cylinder 1 is made of a metallic material, and it is difficult to perform die cutting using a synthetic resin material. When performing die cutting, as shown in FIG.
Since the area of 1a must be cut out in a certain direction (upward in the figure), the contact line (radiation about the cylinder axis) of the cam follower 2a crosses the cutting direction, and the cam follower 2a becomes At the point. As a result, not only the cam efficiency is reduced, but also the joining position of the cam wall is not constant, and the cam design becomes difficult. [Means for Solving the Problems] In view of the above-described problems, the present invention provides, as a first invention, a zoom that performs zooming by moving a moving frame supporting a lens and a driven frame in an optical axis direction. In the lens barrel, an interlocking mechanism that movably supports the driven frame within the moving frame and moves the moving frame and the driven frame together by zooming driving the moving frame, and the movement of the driven frame with respect to the moving amount of the moving frame A zoom mechanism comprising a cam mechanism provided between the moving frame and the driven frame to operate by moving the moving frame in order to move only the driven frame in the moving bay by the difference in the amount. We propose a lens barrel. According to a second aspect of the present invention, in a zoom lens barrel in which a moving frame supporting a lens and a driven frame are moved in an optical axis direction to perform zooming, the zoom frame is screwed into a fixed frame by a helicoid screw, and rotated by zooming. A moving frame that is driven and moved in the optical axis direction; and a pin that communicates with a window hole formed in the moving frame and a guide hole formed in the fixed frame. A driven frame that is provided so as to be moved by movement and moves in the optical axis direction together with the moving frame with respect to the fixed frame; and a light is applied to one of a peripheral portion of the driven frame and a peripheral portion of the moving frame opposed to the peripheral portion. The cam swelled in the axial direction is provided with a cam contact on the other side, and the driven frame is moved relative to the moving frame by rotating the moving frame by the difference between the moving amount of the driven frame and the moving amount of the moving frame. And a cam mechanism for moving. To propose a zoom lens barrel. [Operation] In the zoom lens barrel of the present invention, both the moving frame and the driven frame move in the optical axis direction when the moving frame is driven by zooming. When the moving frame moves, a cam mechanism provided between the moving frame and the driven frame operates, and the driven frame moves forward and backward within the moving frame independently. That is, the driven frame advances and retreats by the cam mechanism by the difference between the moving amount of the moving frame and the moving amount of the driven frame, and moves relative to the moving frame. When the moving frame and the driven frame move in this way, the lenses supported by these frames are displaced to perform zooming. "Example" Next, an example of the present invention will be described with reference to the drawings. 1 and 2 are longitudinal side views of a zoom lens barrel for a camera. FIG. 1 shows a zoomed state at a telephoto position, and FIG. 2 shows a zoomed state at a wide angle position. In these figures, 11 is a fixed frame attached to a camera body or the like, 12 is a moving frame that moves in the fixed frame 11 by a helicoid screw, and 13 is a driven frame that moves in the moving frame 12 by a cam mechanism. Each of the members 11, 12, and 13 is formed in a cylindrical shape from a synthetic resin material or the like that can be die-cut. L ₁ is a fixed lens group supported on a fixed frame 11, L ₂ and L ₃ are movable lens groups supported on a front end and a rear end of a movable frame 12, and L ₄ is a driven lens supported on a driven frame 13. a lens group, a lens L ₂ is focused, but L _1, L _3, L ₄ are each functions as a variable power lens, in particular, L ₄ serves as a correction lens. The fixed frame 11 has a female helicoid screw provided on the inner surface thereof, and has guide holes 11a and 11b elongated and linearly extended along the optical axis direction (cylinder axis direction) above and below the fixed helicoid screw. It is formed. A lens support plate 14 is fixed to the tip (the left end in the figure) of the fixed frame 11 by a small screw 15 screwed through a bush. As shown in FIG. 3, the lens support plate 14 is a disc-shaped one having mounting arms 14a and 14b at the upper and lower sides, and is coaxially fixed to the fixed frame 11, and is provided at the center thereof. the lens holder 16 of the fixed lens group L ₁ is
Is screwed. FIG. 3 is a sectional view taken on line A--A in FIG.
It is the reduced sectional view cut | disconnected along the line. As shown in FIGS. 4 to 6, the moving frame 12 is a bottomed cylindrical body having a male-shaped helicoid screw formed in a rearmost half thereof.
Its the bottom center Yes to stop the lens holder 17 screw of the moving lens group L _3, also, a gear 12a which slightly formed on the enlarged diameter at the tip is provided integrally. Further, the moving frame 12 has a window hole 18 between the helicoid screw portion and the tip gear 12a.
By forming the a and 18b, the connecting arms 12b and 12c having an arc-shaped cross section in which the helicoid screw portion and the gear 12a face each other.
Window hole formed in the helicoid screw part along the circumference of the cylinder.
19a and 19b are provided so as to communicate with the guide holes 11a and 11b of the fixed frame 11. The window holes 18a and 18b allow rotation and advance and retreat of the moving frame 12, but the window holes 19a and 19b allow advance and retreat of the driven frame 13 in addition to the rotation of the movable frame 12. Work like that. On the other hand, bulging cams 12d and 12f are provided on the inner periphery near the bottom surface of the moving frame 12, and the cams 12d and 12f communicate with the driven frame 13. (See FIG. 7) As shown in FIGS. 1 and 2, a pinion 20 for zooming long in the optical axis direction meshes with the gear 12a of the moving frame 12 configured as described above. A helicoid screw is provided on the inner periphery of the distal end of the frame 12, and a rotary cylinder 21 is screwed to the helicoid screw. This rotary cylinder 21 is a lens holder 22 is screwed in the moving lens group L _2, also, a gear 21a which is engaged by the focusing pinion 23 is provided. The focusing pinion 23 is configured to move in the optical axis direction together with the moving frame 12. The driven frame 13 is a cylindrical body integrally formed with a bottom plate 13a having a central hole, and a pin protruding from the cylindrical body to communicate the guide hole 11a of the fixed frame 11 and the window hole 19a of the movable frame 12. (Or roller) 24a, and similarly, a pin (or roller) 24b protruding from the guide hole 11b and the window hole 19b is provided,
In addition, as can be seen from FIG.
Semi-circular cam contacts 13b, 1 facing 12 cams 12d, 12f
3c is integrally formed. The cam contacts 13b and 13c and the cams 12d and 12f of the moving frame 12 constitute a cylindrical cam mechanism. The above cam contact
13b and 13c are always in contact with the cams 12d and 12f by a conical spring 25 provided between the driven frame 13 and the lens support plate 14. Further, the inner bottom surface of the driven frame 13 Yes to stop the lens support plate 26 screws, the lens holder 27 of the movable lens group L ₄ in the support plate 26 are then secured. The lens support plate 26 forms a slight space between the lens support plate 26 and the bottom plate 13a of the driven frame 13, and a shutter blade (not shown) is incorporated in this space. Further, a shutter driving device 28 is attached to the lens support plate 26 at a position within the driven frame 13 as indicated by a provisional line in the drawing. Next, the operation of the above-described zoom lens barrel will be described. When the switch for zoom lens operation is turned on,
The pinion 20 is driven by the rotation of the motor. Here, assuming that the moving frame 12 is in the state of FIG. 1 in which the moving frame 12 is extended, the gear 12a rotates in conjunction with the rotation of the pinion 20, whereby the moving frame 12 rotates according to the helicoid screw. While moving to the right in FIG. The driven frame 13 is kept non-rotating because the pins 24a, 24b protrude into the guide holes 11a, 11b of the fixed frame 11, but the rotation of the moving frame 12 causes the cam contacts 13b, 13c to move. Side cam 12d, 1
Since the vehicle gradually gets up to 2f, it is pushed back against the moving frame 12, and thus moves rightward while moving away from the moving frame 12.
While the driven frame 13 is pushed back by the moving frame 12,
a, 24b move in the window holes 19a, 19b, and the driven frame 13 and the moving frame 12
When the distance between the lens groups L ₄ and L ₃ is a predetermined distance, the pins 24a and 24b are connected to the edges of the window holes 19a and 19b (the sixth edge).
(The lower edge of the hole in the figure). Thus, the rotation of the moving frame 12 is stopped, so that the motor is overloaded, and the switch that detects this overload cuts off the power supply to the motor. In the above-described operation process, the connecting arms 12b and 12c of the moving frame 12 rotate leftward in FIG. 3, the lower edge of the connecting arm 12b approaches the mounting arm 14b of the lens support plate 14, and the upper edge of the connecting arm 12c It comes to approach the mounting arm 14a. Also, the moving lens group L ₄ is a lens unit
The moving distance is small for the displacements of L ₂ and L ₃ , and the distance is determined by a functional condition. Such conditions can be arbitrarily determined by the shapes of the cams 12d and 12f of the moving frame 12. FIG. 2 shows a state in which the telephoto position changes to the wide-angle position in accordance with the above-described zooming. The focusing pinion 23 is driven by a motor included in the automatic distance measuring mechanism, and rotates the rotating cylinder 21 according to a helicoid screw. Rotation of the rotary cylinder 21 is controlled to displace the position of only the moving lens group L ₂ in the optical axis direction focusing. When zooming to the telephoto position, the pinion 20 is rotationally driven in a direction opposite to the above. As a result, the moving frame 12 and the driven frame 13 operate in the opposite manner to the above, and enter the operating state shown in FIG. FIG. 8 is a partial longitudinal side view showing another embodiment of the present invention. In this embodiment, window holes 18a, 19a and 18 provided in the moving frame 12 are provided.
As shown in FIG. 10, b and 19b are a series of window holes 29a and 29b (the window holes 29b are not shown), and the same cams 12d and 12f as described above are provided on the rear edges of the window holes 29a and 29b. Is provided. As shown in FIGS. 9 and 10, the driven frame 13 has a disk shape with tongue pieces 13d and 13e provided at upper and lower positions (the tongue piece 13e is not shown). Pins 24a and 24b and cam contacts 13b and 13c are provided. The tongue pieces 13d and 13e of the driven frame 13 are
Assembled so as to be located within a and 29b. FIG. 9 is a reduced sectional view taken along line BB in FIG. Although the operation of this embodiment is the same as that of the above-described embodiment, it can be implemented as a two-layer structure of a cylindrical body, which is advantageous for reducing the diameter of the zoom lens barrel. Although the embodiment of the present invention has been described above, the outer surface of the fixed frame 11 is formed in a plane, and the swelling cams 12b and 12f are
In addition, a change such as providing semicircular cam contacts 13b and 13c on the moving frame 12 is optional. Also, these cams are not necessarily 2
It is not necessary to form a pair, and similarly, the pins 24a and 24b
The number of a and 11b may be increased or decreased as necessary, and the window of the moving frame 12 may be formed in accordance with the number of pins. The present invention has a configuration in which an optical system that moves non-linearly is driven linearly in the optical axis direction with respect to an optical system that moves linearly in the optical axis direction with a helicoid screw, and the distance between these two optical systems is set to Since it is changed by a cam mechanism provided on the support frame, a widely known configuration in which a master lens and a focusing lens are fixed and a variable power lens and a correction lens are displaced between these lenses. The zoom lens barrel can be easily implemented. The present invention is not limited to a camera for photographing, but can be widely used as a zoom lens barrel of a small-sized camera or a video camera, but when implemented for a video camera, the bottom plate 13a of the driven frame 13 and the lens An aperture blade may be provided in the space with the support plate 26 instead of the shutter blade. Also,
In practicing the present invention, the moving frame 12 is used without an automatic zooming control mechanism linked to the pinions 20 and 23.
Alternatively, a zoom lens barrel that manually operates the rotary cylinder 21 may be used. [Effects of the Invention] As described above, the zoom lens barrel of the present invention has a configuration in which the driven frame moves together with the moving frame and the driven frame is moved and driven by the cam mechanism by a difference with respect to the moving amount of the moving frame. Therefore, the distance between the lens supported by the moving frame and the lens supported by the driven frame is accurately determined, and a highly accurate zoom lens barrel is obtained. In addition, each component of the zoom lens barrel can be easily produced by die cutting. As a result, the structure can be simplified and the size can be reduced, and the zoom lens barrel can be small and lightweight. Furthermore, since the unit cost of each part is reduced and the number of assembling steps is reduced, a zoom lens barrel with reduced cost can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are longitudinal side views of a zoom lens barrel showing an embodiment of the present invention. FIG. 1 is zoomed to a telephoto position, and FIG. 2 is zoomed to a wide angle position. Each state is shown. 3 is a reduced sectional view taken along the line AA in FIG. 1, FIG. 4 is a front view of the moving frame, FIG. 5 is a side view of the moving frame, and FIG. FIG. 7 is a simplified view showing a cam interlocking state between a moving frame and a driven frame, FIG. 8 is a partial longitudinal side view of a zoom lens barrel showing another embodiment of the present invention, and FIG. The figure is a reduced sectional view taken along the line BB in FIG.
FIG. 11 is a plan view of a moving frame in the second embodiment, FIG. 11 is a plan view showing a cam cylinder and a moving cylinder shown as a conventional example, FIG. 12 is a cross-sectional view taken along line CC in FIG. FIG. 13 and FIG. 14 are explanatory views for explaining a joint state between the cam hole of the cam cylinder and the cam follower. 11 ... fixed frames 11a, 11b ... guide holes 12 ... moving frames 12b, 12c ... connecting arms 12d, 12f ... cams 13 ... driven frames 13b, 13c ... cam contacts 18a, 18b, 19a, 19b. …… Window holes 24a, 24b …… Pin 25 …… Spring

Continuation of the front page (72) Inventor Hirotaka Joshi 6-27-8 Jingumae, Shibuya-ku, Tokyo Kyocera Corporation Tokyo Harajuku Office (72) Inventor Itsuro Doi 2800 Nagachi, Okaya-shi Kyocera Corporation Nagano Okaya Factory (56) References JP-A-54-5424 (JP, A) JP-A-55-120007 (JP, A) JP-A-57-37306 (JP, A) Japanese Utility Model Laid-open No. 59-95306 (JP, U) ( 58) Field surveyed (Int. Cl. ⁶ , DB name) G02B 7/04 G02B 7/10

Claims (1)

(57) [Claims] In a zoom lens barrel that performs zooming by moving the moving frame supporting the lens and the driven frame in the optical axis direction, the driven frame is movably supported within the moving frame, and the moving frame is moved by zooming drive. An interlocking mechanism that moves the frame and the driven frame together, and a difference between the moving amount of the driven frame and the moving amount of the moving frame, between the moving frame and the driven frame to move only the driven frame within the moving frame. A zoom lens barrel comprising: a cam mechanism provided to operate by moving the moving frame. 2. In a zoom lens barrel that moves the moving frame supporting the lens and the driven frame in the optical axis direction to perform zooming, the lens is screwed into the fixed frame by a helicoid screw, and is rotated in zooming to move in the optical axis direction. A moving frame to be moved, and a pin communicating with a window hole formed in the moving frame and a guide hole formed in the fixed frame, and provided so as to move non-rotatably along an inner peripheral surface of the moving frame, and fixed. A driven frame that moves in the optical axis direction together with the moving frame with respect to the frame, and a cam formed to bulge in the optical axis direction on one of a peripheral portion of the driven frame and a peripheral portion of the moving frame facing the peripheral portion. And a cam mechanism for moving the driven frame relative to the moving frame in accordance with the rotation of the moving frame by the difference between the moving amount of the driven frame and the moving amount of the driven frame. A zoom lens barrel.