JP3748120B2 - Zoom lens barrel that drives a two-component lens group - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a zoom lens barrel composed of two components, and more particularly, to a two-component zoom lens barrel that is simplified in configuration and its cost is reduced and the size is reduced.
[0002]
[Prior art]
In the case of a zoom drive mechanism in a conventional two-component zoom lens barrel, for example, as shown in FIG. 9, a fixed barrel 30, a zoom cam ring 31 fitted in the fixed barrel 30, and a zoom provided on the outermost periphery of the barrel. Each guide pin 34 provided on the first and second lens moving frames 33 (only one shown in the figure) is provided on the straight guide 35 provided on the fixed cylinder 30 and the zoom cam ring 31. A zoom interlocking pin 37 that engages with the provided cam groove 36 and extends from the zoom operation ring 32 is connected to the zoom cam ring 31. Reference numeral 38 denotes a focus cam ring.
[0003]
When the zoom operation ring 32 is rotated, the movement is transmitted to the zoom cam ring 31 via the zoom interlocking pin 37, and the cam ring 31 rotates. By the rotation of the cam ring 31, the guide pins 34 of each lens moving frame 33 are guided by the cam grooves 36 corresponding to the respective guide pins 34 and the straight guides 35 of the fixed cylinder 30. Moves in the direction of the optical axis.
[0004]
[Problems to be solved by the invention]
However, in the case of the above-described conventional configuration, the zoom operation ring 32 and the zoom cam ring 31 are configured as separate parts, and furthermore, these parts 31 and 32 are multiplely fitted around the lens. Not only was it impossible to reduce the number of points, but it was also a major obstacle to reducing the size of the lens barrel. In addition, separate molds are required for molding the zoom operation ring 32 and the zoom cam ring 31, and the cost is reduced due to the complexity of the mold configuration and the time required for assembly. There was a problem that there was a limit.
[0005]
The present invention has been made to solve the above-described conventional problems, and in manufacturing a zoom lens barrel, the number of components can be reduced to achieve miniaturization, and further cost reduction can be achieved. An object of the present invention is to provide a novel two-component zoom lens driving mechanism that can be used.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a fixed cylinder having a first lens group, a second lens group, a rectilinear guide of the first and second lens groups, and a notch formed between the rectilinear guides. If the located on the outer peripheral side of the fixed cylinder, the rotary operating cylinder having a first lens cam follower and the cam for the second lens group driving unit on the inner peripheral surface side, located on the inner peripheral side of the fixed cylinder, the A movable frame body cylinder having a first lens group cam facing the first lens group cam follower on the outer peripheral surface side, and each of the first lens group cam follower and the first lens group cam is the fixed cylinder. wherein there the cutout portion, by the rotating operation tube outer peripheral surface of the first lens group and the second lens group by operating the is adapted to be driven in the optical axis direction, with one part, 2 Component zoom operation member and movement You can share, it is possible to thereby reduce the number of parts. In addition, the size and cost can be reduced.
[0007]
In the above configuration, by forming at least one of the first lens group cam and the second lens group cam by a sandwiching cam, it is possible to use a two-surface split mold in the manufacturing stage of the rotary operation cylinder. It becomes. Accordingly, the mold configuration is simple and can be manufactured at low cost.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a zoom lens barrel according to the present invention will be described with reference to the drawings. FIG. 1 shows the appearance of a zoom lens barrel of this embodiment and a camera equipped with the same. The camera C shown in this figure is a single-lens reflex camera to which a plurality of types of photographing lenses can be attached and detached, and has an AF (automatic focus adjustment) function and an AE (automatic exposure adjustment) function. In the center, a lens mounting mount M is formed. Although not shown, a power supply battery for supplying power to the camera and lens drive system, the display system, the photometry system, and the like is detachably mounted in the body B.
[0009]
2 and 3 show the zoom lens barrel L of the present embodiment, FIG. 2 shows each component, and FIG. 3 shows an assembled state. The zoom lens barrel L shown in these drawings includes a first lens group G1 fixedly supported by the first group holding frame 1 and a second lens group G2 fixedly supported by the second group holding frame 2. In addition, zooming is performed by moving the first and second lens groups G1 and G2 in the optical axis direction, and focusing is performed mainly by moving the first lens group G1 in the optical axis direction. Yes. 3 is a fixed cylinder, 4 is a zoom operation ring, 5 is a focus feed cylinder, and 6 is a zoom feed cylinder. 4A shows the zoom operation ring 4, FIG. 4B shows the zoom supply cylinder 6, and FIG. 4C shows the fixed cylinder 3 in an expanded state.
[0010]
The first group holding frame 1 is attached to the focus feeding cylinder 5 so as to be movable in the optical axis direction. Moreover, although not shown, the first group holding frame 1 is provided with a gear which meshes with helicoid gears example, a focusing motor provided on the Bode I side via a helicoid gear, the drive transmission mechanism and coupler Are combined. At the time of focusing, the focusing motor is driven based on the data detected by the AF unit, and the output is transmitted to the helicoid gear via the coupler and the drive transmission mechanism. Driven in the axial direction.
[0011]
In addition, the distance motor (not shown) is electrically connected to the focus motor or mechanically coupled to the helicoid gear so that the focus motor is driven by manually operating the distance ring. Alternatively, the helicoid gear is directly driven to rotate and manual focusing is performed.
[0012]
The focus feeding cylinder 5 is coupled to the zoom feeding cylinder 6. The zoom feed cylinder 6 has a first group cam follower 7 and a first group rectilinear projection 8 formed of curved ridges formed at different positions on the outer peripheral surface at equally divided portions on the outer peripheral surface 3. 7 is engaged with a first group cam 9 formed on the inner peripheral surface of the zoom operation ring 4, and the first group rectilinear projection 8 is a first group rectilinear advance formed on the inner peripheral surface 3 of the fixed cylinder 3. The guide groove 10 is engaged.
[0013]
The second group holding frame 2 includes linearly-moving guide pieces 11 that extend radially at three equal parts on the outer periphery, and these straight-advance guide pieces 11 are formed at the three parts of the peripheral surface 3 of the fixed cylinder 3. The second group rectilinear guide groove 12 is engaged, and the second group lead groove 13 formed in the inner peripheral surface 3 of the zoom operation ring 4 is equally engaged. Each linear guide piece 11 is formed with a spring portion 11a having a radially intermediate portion formed into a U-shape, and the linear guide piece 11 is given elasticity by the spring portion 11a. 11 abuts on the second group lead groove 13 with an optimum biasing force.
[0014]
Further, a rotation restricting groove 14 for restricting the rotation range of the zoom operation ring 4 is formed between each second group rectilinear guide groove 12 of the fixed cylinder 3, while the peripheral surface 3 of the zoom operation ring 4 and the like. An insertion hole 15 is formed in each minute part. As will be described later, a rotation restricting member 16 (see FIG. 7) is inserted into these insertion holes 15 and fixed by screws 17 so that the rotation restricting member 16 faces the rotation restricting groove 14 and By contacting both ends, the zoom operation ring 4 is restricted from further rotation at the wide end and the tele end.
[0015]
In the zoom lens barrel L having the above-described configuration, unlike the conventional zoom lens, the zoom operation ring 4 itself is integrally formed with a cam or cam follower of the cam mechanism, and functions as both an operation ring and a zoom cam ring. Therefore, it is possible to reduce the number of parts and reduce the size of the lens barrel. Note that the components of the cam mechanism are exposed on the surface of the zoom operation ring 4 in the form of holes. These hole parts are exposed on the outer peripheral surface of the operation ring 4 as shown in FIG. It is covered with a slip-on anti-slip member 18 so that it is not exposed to the outside.
[0016]
When the zooming operation is performed, the rotation of the zoom operation ring 4 is transmitted to the first group and the second group holding frames 1 and 2 via the cam mechanism without passing through the cam ring. That is, when performing zoom operation from the wide-angle side to the telephoto side or in the opposite direction, when the zoom operation ring 4 is manually rotated, the first group cam follower 7 is driven by the rotation of the first group cam 9, thereby zooming in. The feeding cylinder 6 is guided in the optical axis direction by the first group rectilinear guide groove 10 so that the focus feeding cylinder 5 and the first group holding frame 1 are integrally moved in the optical axis direction. At the same time, the second group rectilinear guide piece 11 follows the rotation of the second group lead groove 13 of the zoom operation ring 4, whereby the second group holding frame 2 is guided in the optical axis direction by the second group rectilinear guide groove 12. Thus, the second group holding frame 2 is integrally guided in the optical axis direction, and zooming is performed.
[0017]
In the above configuration, the first group cam 9 is constituted by a sandwiching cam. As shown in FIG. 2, the first group cam 9 composed of the sandwiching cam is provided with a square hole 9a at one end side of the zoom operation ring 4 at a predetermined phase, and is opposed to the front and rear sides of the square hole 9a. The pair is formed by integrally forming a pair of sandwiching pieces 9b projecting to the inner diameter side, with the first group cam follower 7 of the zoom feeding cylinder 6 made of a curved ridge being sandwiched between the sandwiching pieces 9b on both sides. It is configured to lead.
[0018]
In this way, by using the sandwiching cam having the sandwiching pieces 9b opposed in the axial direction of the zoom operation ring 4, it is possible to use a mold having two planes in the axial direction in the manufacturing stage of the zoom operation ring 4. Therefore, there exists an advantage that it can manufacture with a simple and cheap metal mold | die. For convenience of explanation, the cam configuration on the zoom feed cylinder 6 side is referred to as a cam follower 7 and the cam configuration on the zoom operation ring 4 side is referred to as a cam 9, but it can be said that the cam and the cam follower are relative names.
[0019]
Next, the construction and assembly procedure for assembling the zoom lens barrel L having the above construction will be described. As shown in FIG. 4A, the second group lead groove 13 of the zoom operation ring 4 has a drive region. The over tele area to continues from the tele end and the over wide area wo continues from the wide end of the drive area. Further, as shown in FIG. 4C, the first group cam follower is located at a position where the first group cam follower 7 of the zoom feeding cylinder 6 faces between the second group linearly moving guide grooves 12 of the fixed cylinder 3. 7 and the first group cam 9 are formed with a notch 19 that can be exposed to the outside in a parallel state.
[0020]
When the zoom feeding cylinder 6 in which the first lens group G1, the first group holding frame 1 and the focus feeding cylinder 5 are incorporated in the fixed cylinder 3 and the zoom operation ring 4, as shown in FIG. The zoom feeding cylinder 6 is fitted into the fixed cylinder 3 so that the first group cam follower 7 of the feeding cylinder 6 faces the notch 19, and the zoom operation ring 4 fitted on the outer diameter side of the fixed cylinder 3 is set to the tele side. By rotating, the over tele area to of the second group lead groove 13 is made to coincide with the tele end of the first group cam follower 7 of the zoom feed cylinder 6. In this state, the first group cam 9 is arranged on the extension of the wide end of the first group cam follower 7 in the notch 19 of the fixed cylinder 3, and the zoom operation ring 4 is rotated to the wide side from here. As a result, the first group cam follower 7 is sandwiched and engaged with the first group cam 9, whereby the configuration of the first group is incorporated into the lens barrel.
[0021]
Next, when the second group holding frame 2 for holding the second lens group G2 is incorporated into the fixed cylinder 3 and the zoom operation ring 4, as shown in FIG. The zoom operation ring 4 is further rotated to the wide side until the over-wide region wo of the second group lead groove 13 of the zoom operation ring 4 overlaps with the end of the second group straight-advancing guide groove 12 of the cylinder. By inserting the second group rectilinear guide piece 11 from the portion, the configuration of the second group can be incorporated into the lens barrel.
[0022]
As described above, if the cam mechanism is provided with the over-wide area wo and the over-tele area to and the configurations of the first group and the second group are incorporated in these areas wo and to, Is easy to understand and can reduce assembly man-hours.
[0023]
As described above, when the first group and the second group are assembled into the lens barrel, as shown in FIGS. 7 and 8, after the rotation restricting member 16 is inserted into the insertion hole 15 of the zoom operation ring 4, By screwing, the rotation of the zoom operation ring 4 is restricted within the range of the rotation restricting groove 14 of the fixed cylinder 3, and overtraveling to over-wide and over-tele is prevented.
[0024]
The rotation restricting member 16 has, for example, an octagonal frame shape as shown in the figure, a screw hole 20 is formed at the center, and a non-rotating protrusion 21 is provided on an upper surface portion passing through the screw hole 20. It will be. On the other hand, the insertion hole 15 of the zoom operation ring 4 is provided in a range not including the over-wide region and the over-tele region of the cam mechanism, and is fitted into a rectangular shape with vertical and horizontal dimensions that can receive the rotation restricting member 16. Part 15a and a lateral hole part 15b having a height substantially equal to the thickness of the rotation restricting member 16, and the upper surface of the lateral hole part 15b is opened to the fitting part 15a, and the rotation preventing projection of the rotation restricting member 16 An anti-rotation groove 22 that allows 21 to be inserted is formed.
[0025]
When the rotation restricting member 16 is fixed to the insertion hole 15, the rotation restricting member 16 is inserted into the fitting portion 15a and then slid into the lateral hole portion 15b. As a result, the rotation restricting member 16 enters the rotation restricting groove 14 of the fixed cylinder 3 and the rotation preventing projection 21 is engaged with the rotation preventing groove 22 to prevent rotation. By fixing the screw 17 to the screw hole 20 of the rotation restricting member 16 from this state, the rotation restricting member 16 is prevented from rotating around the rotation restricting groove 14, so that the force in the loosening direction applied to the screw 17 is greatly reduced. It becomes difficult to loosen.
[0026]
【The invention's effect】
As described above, according to the present invention, the two-component zoom operation member and the moving cam can be shared by a single component, thereby reducing the number of components. In addition, since the number of parts can be reduced, especially the number of parts arranged in multiples around the lens can be reduced, it is possible to reduce the size and the cost.
[0027]
In addition, it is possible to use a two-sided mold in the production stage of the rotary operation cylinder. Therefore, the structure of the mold is simple and can be manufactured at low cost, and further effective manufacturing cost reduction can be realized.
[Brief description of the drawings]
FIG. 1 is an external perspective view showing an example of a zoom lens barrel and a camera equipped with the zoom lens barrel according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view showing components of a zoom lens barrel.
FIG. 3 is a half-sectional view schematically showing the assembled state.
4A and 4B are development views showing (A) a zoom operation ring, (B) a zoom feed cylinder, and (C) a fixed cylinder.
FIG. 5 is a development view showing when the first group is assembled.
FIG. 6 is a development view showing when the second group is incorporated.
FIG. 7 is an exploded perspective view showing a rotation restricting member and an insertion hole.
FIG. 8 is a sectional view showing the assembled state.
FIG. 9 is a cross-sectional view showing a schematic configuration of a conventional example.
[Explanation of symbols]
1 First group holding frame 2 Second group holding frame 3 Fixed cylinder 4 Zoom operation ring 5 Focus feeding cylinder 6 Zoom feeding cylinder 7 First group cam follower 8 First group rectilinear protrusion 9 First group cam 10 First group rectilinear guide groove 12 Second group rectilinear guide groove 13 Second group lead groove 14 Rotation restriction groove 15 Insertion hole 16 Rotation restriction member 17 Screw G1 First lens group G2 Second lens group L Zoom lens barrel

Claims (2)

A fixed cylinder having a first lens group, a second lens group, a rectilinear guide of the first and second lens groups and a notch formed between the rectilinear guides, and an outer peripheral side of the fixed cylinder; A rotary operation cylinder having a first lens group cam follower and a second lens group cam on its inner peripheral surface side, and an inner peripheral side of the fixed cylinder, and the first lens group cam follower on its outer peripheral surface side. A movable frame body cylinder having a first lens group cam opposed to each other, wherein the first lens group cam follower and the first lens group cam are respectively in the cutout portion of the fixed cylinder, and the rotation operation cylinder the first lens group and the second lens group is characterized by being configured to be driven in the optical axis direction, a zoom lens barrel which drives a lens group of the two components by manipulating the outer peripheral surface of the. A cam for the first lens group at least one of the cam for the second lens group, entrapment of claim 1 which is constituted by a cam, a zoom lens barrel which drives a lens group of the two components.

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