JPH0723764Y2 - Zoom lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a zoom lens barrel used in optical equipment such as a camera for photographing, a small-sized photographing machine, a video camera, a copying machine, and an enlarger.

“Prior Art” A zoom lens barrel includes a cam barrel having a long and narrow cam hole along the circumference and a cam follower (having a roller around the pin) projected into the cam hole. It is provided with a movable barrel that is internally mounted and supports a variable-magnification lens and a correction lens, and by rotating the cam barrel, the movable barrel is moved in the optical axis direction for optical variable magnification. It is configured to do.

In many cases, a plurality of moving barrels are actually installed in the cam barrel, and each of these moving barrels moves in conjunction with the cam barrel while being guided by the fixed barrel.

Further, the zoom lens barrel described above is formed of a metallic material because it is difficult to perform die-cutting processing using a synthetic resin material or the like because the cam cylinder is an elongated cam hole along the circumference. Therefore, not only the production efficiency is low, but also the cost is high.

Therefore, in order to solve this problem, the inventors of the present application have developed a cam cylinder of this kind that can be produced by die cutting, and have applied for a utility model registration application No. 162178 in 1986 and a utility model registration application in 1987. Already filed as No. 4353.

The cam cylinder of this application has one side cam hole formed by cutting from one end in the cylinder axial direction and the other end cut in the cylinder axial direction by
The other side cam hole formed by changing the cylinder peripheral position with respect to the one side cam hole is provided, and both or one of the one side cam hole and the other side cam hole is covered around the cam cylinder. A cover plate is provided and a cam surface parallel wall is formed on this plate part so as to come close to the cam follower that presses against the cam surface of the cam hole. When viewed from the cylinder periphery, the cam surface is parallel to the cam surface. It is configured to form a cam hole with the wall,
Further, the cam barrel is attached to the fixed frame in a bayonet form.

Since such a cam barrel can be die-molded using a synthetic resin material or the like together with the respective components such as the movable barrel and the fixed barrel, it is possible to provide a zoom lens barrel having an assembly structure using the die-cut components. .

"Problems to be solved by the invention" In the case of the zoom lens barrel described above, since the cam barrel, the moving barrel, the fixed barrel, etc. are the die-cutting parts, the roundness thereof is likely to collapse during the die-cutting formation or assembly. In addition, there is a problem that the coaxiality is difficult to appear when assembled and polymerized, and the optical performance is deteriorated.

In particular, because the movable barrel and the fixed barrel are equipped with respective lens groups for zooming, if any distortion or deflection occurs in them, the movable barrel will not move accurately according to the fixed barrel. The optical axis of the lens group is deviated and the image performance deteriorates.

Therefore, in the present invention, the distortion and deflection of the movable barrel and the fixed barrel are reduced as much as possible to increase the coaxiality between the movable barrel and the fixed barrel, and the movement of the movable barrel caused by fixing the lens group is eliminated. Its main purpose is to prevent the roundness from breaking.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a movable cylinder provided with a cam follower that is in contact with the cam surface of the cam cylinder along the fixed cylinder in association with the rotation of the cam cylinder. In the zoom lens barrel configured to move the optical system supported by the moving barrel and change the position of the optical system to optically change the magnification, a moving barrel is provided around the fixed barrel and a cam barrel is provided around the moving barrel. As each polymerizes,
The outer surface of the fixed cylinder is provided with a concave groove along the optical axis of the optical system, and the inner surface of the movable cylinder is provided with a convex portion extending between the cylinder ends slidably fitted in the concave groove, and A zoom lens barrel is proposed in which the outer peripheral portion of the lens support frame is brought into contact with the thick portion of the end surface of the movable cylinder where the convex portion is located to fix the support frame.

"Operation" Since the moving tube moves in the direction of the optical axis while the ridge formed on the moving tube is fitted in the groove of the fixed tube, the coaxial accuracy of the moving tube with respect to the fixed tube is high, and The optical axes of the respective lens groups provided in the above are substantially matched with each other without any error, and the ridge portion serves as a kind of reinforcing portion to prevent distortion and bending of the moving cylinder.

Further, since the portion of the end surface of the moving cylinder where the convex portion is located has a wall thickness in the cylinder radial direction, the lens support frame is fixed to the wall thickness portion with a screw or the like screwed in the cylinder axis direction.

As a result, since the force due to screwing does not act in the radial direction of the moving barrel, the moving barrel can accurately maintain the coaxiality with the fixed barrel without bending.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a zoom lens barrel according to the present invention, and FIG.
1 is a sectional view of the zoom lens barrel taken along line AA in FIG. 1, and FIG. 3 is an exploded perspective view of the zoom lens barrel.

In these figures, 11 is a fixed barrel attached to the camera body, 12 is a moving barrel that moves on the outer surface of the fixed barrel 11, 13
Is a moving frame that moves in the fixed barrel 11, and 14 is a cam barrel that is rotatably provided around the moving barrel 12.

Further, L ₁ is a fixed lens group supported by the fixed barrel 11, L ₂ and L ₃
Is a movable lens group supported by the front and rear ends of the movable barrel 12,
L ₄ represents a moving lens group is supported by the movable frame 13, as lens L ₂ is focused, but L _2, L _3, L ₄ are each functions as a variable power lens, in particular, L ₄ is a correction Work as a lens for.

The fixed cylinder 11 has a guide groove 11 extending linearly in the upper and lower directions in FIG. 1 along the optical axis direction (cylinder axis direction).
A and 11b, and left and right sides thereof are provided with wide cutout holes 11c and 11d (see FIGS. 2 and 3) extending in the cylinder axis direction with the rear end side opened.

The guide grooves 11a and 11b guide the movable barrel 12 in a non-rotatable manner in the optical axis direction, and the notch holes 11c and 11d are notched holes that allow the movable frame 13 and the lens support frame 15 to move in the barrel axis direction.

Further, a lens support portion 11e is integrally provided in a partition shape from the slightly inner end of the fixed barrel 11, and the support portion 11e
The lens holder 16 of the fixed lens unit L ₁ is screwed to. The lens support portion 11e is provided with an arc-shaped through hole 11f, in which a swivel rod 22 for defining the turning range of the moving lens group L ₂ for focusing is provided on the stopper wall of the fixed barrel 11.
Insert loosely between 11j and 11k. This will be described later.

Further, on the peripheral surface of the cylindrical portion formed at the front side of the fixed cylinder 11, four groove grooves 11g are formed along the cylinder axis direction between the cylinder tip and the notch holes 11c and 11d. These groove 1
1g enhances the coaxiality between the fixed cylinder 11 and the movable cylinder 12. Locking claws 11h and 11i are provided at the rear end of the fixed cylinder 11, and a cam cylinder 14 described later is attached as a bayonet structure.

The above-mentioned movable barrel 12 has cam followers 17a and 17b on the upper side and the lower side in FIG. 1, and guide holes 12a and 12b that extend linearly in the optical axis direction on the left and right sides thereof (see FIG. 2). ) And. The cam followers 17a, 17b have rollers around the pins, and these are fixed to the sliding portions 12c, 12d formed on the inner surface of the movable cylinder in the cylinder axial direction,
These sliding portions 12c and 12d slide in the guide grooves 11a and 11b of the fixed cylinder 11. The guide holes 12a and 12b described above are loosely inserted with cam followers of a moving frame 13 which will be described later. Further, a rotating barrel 19 screwed with a helicoid screw is provided at the tip of the moving barrel 12, and the lens holder 20 of the moving lens unit L ₂ is screwed to the rotating barrel 19.

A gear 19 engaged with a focusing pinion 21 is attached to the rotary cylinder 19.
a is integrally formed, and by this rotation, the moving lens unit L
_The position of ₂ is changed. The turning limit of the turning barrel 19 is set by a turning rod 22 protruding from the lens holder 20 toward the inside of the fixed barrel 11.

The focusing pinion 21 is provided on a lens mounting frame (not shown) to which the fixed barrel 11 is mounted, and is rotationally driven in conjunction with a focusing motor.

Further, on the inner surface of the movable cylinder 12, four convex streak portions 12e extending from the cylinder front end to the cylinder rear end are provided along the cylinder axis direction. These convex strips 12e are fitted in the concave slits 11g of the fixed barrel 11 to maintain the coaxiality of the movable barrel 12, and also form the fastening portions of the lens support frame 15, as described below.

That is, the above-mentioned lens support frame 15 is screwed to the rear end of the movable barrel 12, and the lens holder 24 of the movable lens group L ₃ is screwed to this support frame 15.

As shown in FIG. 3, the lens support frame 15 is a disk-shaped member having symmetrically-arranged arc-shaped expanded portions 15a and 15b, and these expanded portions 15a and 15b are formed in the cutout hole 11c of the fixed cylinder 11. , 11d to be loosely attached and fixed to the rear end of the movable barrel 12.

As shown in the drawing, each of the expanded diameter portions 15a and 15b has a raised portion 15a ₁ and 15
b ₁ and the horizontal installation parts 15a ₂ and 15b ₂
Fit a ₂ and 15b ₂ on the inner surface of the rear end of the moving barrel 12 and
Place a ₁ and 15b ₁ on the rear end of the moving cylinder and screw it in place. In this case, the small holes provided in the upright portions 15a ₁ and 15b ₁ are aligned with the screw holes 12f (see FIG. 6) provided at the rear end of the moving cylinder, and the horizontal portions 15a ₂ and 15b are made to correspond to the small holes. _The ridge 12e of the movable cylinder 12 is fitted or loosely fitted in the groove formed in ₂ , and the machine screw 18 is screwed in as shown in FIG.

As can be seen from the perspective view of FIG. 3, the movable frame 13 is a disk-shaped member having symmetrically formed arc-shaped expanded portions and a central hole, and each expanded portion is provided in the optical axis direction. Raised protrusions 13e, 13f
The circular curved surface portions 13a and 13b having the above are integrally formed, and the cam followers 26a and 26b, which are pin-shaped rollers, are provided on the protruding portions 13e and 13f of the circular curved surface portions 13a and 13b. Cam follower 26
As shown in FIG. 2, a and 26b are provided so as to be retractable on the surface of the projecting portion, but the projecting force is always applied by the expansion springs 25a and 25b.

The concave groove 13g provided on both sides of the protrusions 13e and 13f is for fitting or loosely fitting the convex portion 12e of the movable barrel 12.

Further, the plate surface of the moving frame 13 on the side of the circular curved surface is used as the base of the shutter mechanism, the blade pressing plate 27 is screwed, and the lens holder 28 of the moving lens unit L ₄ is provided in the center.

As can be seen from FIGS. 1 and 2, the movable frame 13 having the above-mentioned configuration allows the circular curved surface portions 13a and 13b to be loosely inserted into the cutout holes 11c and 11d of the fixed barrel 11, and the protruding portion 13e provided on the circular curved surface portion. , 13f formed on the inner surface of the movable barrel 12 along the optical axis direction, and sliding grooves 12g, 12h.
Further, the cam followers 26a and 26b are freely inserted into the guide holes 12a and 12b of the moving barrel 12 and are brought into contact with the cam surface of the cam barrel 14.

On the other hand, as shown in the perspective view of FIG. 3, the fixed barrel 11 has two stopper walls 11j and 11k extending parallel to the optical axis direction.
Is provided. At wide angle, the swivel rod 22 passes through an arc-shaped through hole 11f provided in the lens support portion 11e of the fixed barrel 11, and at telephoto, the swivel rod 22 moves to the left from the position of the through hole 11f. A swivel rod that defines the turning range of the group L _2.
A turning region of 22 is formed, and the turning rod 22 comes into contact when turning within a predetermined range.

In addition, a coil spring 30 for expanding the pressure is provided between the moving frame 13 and the lens supporting frame 15 fixed to the moving barrel 12 to move the moving frame 13 to the first position.
A spring biasing force that constantly pushes the movable barrel 12 in the right direction in the figures is applied in the left direction in the figures and FIG.

In this embodiment, a slight space is formed between the moving frame 13 and the blade pressing plate 27, and a shutter blade (not shown) is incorporated in this space.

The shutter drive device has a circular curved surface portion as shown by a phantom line 29 in the figure.
The movable frame 13 is assembled so as to be positioned inside the 13a and 13b.

As can be seen from the perspective view of FIG. 3, the cam barrel 14 described above is
The tubular body is provided with one side cam holes 31 and 32 provided on the front side and the other side cam holes 33 and 34 provided on the rear side.

FIG. 4 is a development view of the cam cylinder 14, and as shown in the drawing, the one side cam holes 31 and 32 are notched holes formed by cutting in the axial direction from the symmetrical portion at one end of the cylindrical body, The linear cut inclined sides 31a, 32a form a cam surface, and the other side cam holes 33, 34 are notched holes formed by cutting in the cylinder axis direction from the symmetrical portion at the other end of the cylindrical body, Inclined side 33
a and 34a form a cam surface.

The cam cylinder 14 has plate portions 14a and 14b integrally formed on the outer periphery of the cam cylinder 14 so as to cover the one side cam holes 31 and 32, and the other side cam hole 33, With respect to 34, the same plate portions 14c and 14d as described above are integrally formed, and the flange portions 14e and 14f are integrally formed along the outer periphery of the rear end.

The plate portions 14a and 14b described above have a substantially triangular shape, and the inclined portion forms a cam surface parallel wall parallel to the cam surfaces 31a and 32a. The cam surface parallel wall is located at a position where the heads of the cam followers 17a and 17b can come into contact with each other by expanding the diameter in the cylinder circumferential direction as compared with the cam surfaces 31a and 32a.

The plate portions 14c and 14d have the same configuration.

On the other hand, the cam barrel 14 is provided with a gear portion 14g around the rear end thereof slightly inward, and the zoom pinion 35 is provided.
Are engaged as shown in FIG. The zooming pinion 35 is provided on the lens mounting frame to which the fixed barrel 11 is mounted.

The cam cylinder 14 has flange portions 14e and 14f with locking claws of the fixed cylinder 11.
Although it is attached to the fixed barrel 11 in a bayonet manner so as to be locked to 11h and 11i, a stopper that determines the rotation range of the cam barrel 14 is provided after the attachment so as not to come off.

As indicated by a phantom line in FIG. 4, the cam followers 17a and 17b of the moving cylinder 12 are in contact with the cam surfaces 31a and 32a of the above-mentioned one side cam holes 31 and 32, and the other side cam holes 33 and 34. The cam surface 33
The cam followers 26a and 26b of the moving frame 13 are attached to a and 34a so as to be in contact with each other.

Next, the operation of the zoom lens barrel described above will be described.

Assuming that the movable barrel 12 is pushed back and is in the wide-angle state shown in FIGS. 1 and 2, the cam followers 17a, 17 are provided.
b, 26a, and 26b are in a contact relationship with the cam barrel 14 as shown in FIG. When the switch is turned on for the zoom operation, the zooming pinion 35 is driven by the rotation of the motor. As a result, the cam cylinder 14 that is interlocked with the pinion 35 turns right when viewed from the front (left side in FIG. 1), and the cam followers 17a and 17b are moved to the cam surfaces 31a of the one side cam holes 31 and 32. The movable cylinder 12 is pushed by 32a and moves in the leftward direction in FIGS. 1 and 2 against the pressure expanding action of the coil spring 30. Further, the cam followers 26a, 26b receive the pushing force of the coil spring 30 and move in the optical axis direction as the cam surfaces 33a, 34a of the cam holes 33, 34 on the other side rotate, which causes the moving frame 13 to move. It moves to the upper left in FIGS. 1 and 2.

In the above movement process, the sliding portions 12c and 12d are guided by the guide grooves 11a and 11b of the fixed barrel 11, and the ridge 12e is fixed to the fixed barrel 11.
Sliding while fitting in the concave groove 11g of
The gear 19a of the rotary cylinder 19 which is moved between the cam cylinder 14 and the cam cylinder 14 without rotation and which is screwed to the tip of the movable cylinder 12 is in the left direction in a state of being meshed with the focusing pinion 21. Moving.

In the moving frame 13, the protruding portions 13e and 13f of the circular curved surface portions 13a and 13b are guided by the sliding grooves 12g and 12h of the moving barrel 12, and the concave groove 13g is formed.
Moves in the protruding portion 12e of the movable barrel 12 while being fitted or loosely fitted, so that it slides to the left in the fixed barrel 11 without rotating, and the circular curved surface portions 13a and 13b are notches of the fixed barrel 11. It moves in the holes 11c and 11d.

When the cam cylinder 14 reaches a predetermined rotation position, the ends of the flange portions 14e and 14f hit the stoppers and the rotation of the cam cylinder 14 stops.

As a result, the motor that drives the zooming pinion 35 becomes overloaded, and the switch that detects this overload shuts off the power supply to the motor.

FIG. 7 shows a state in which the zoom lens is moved from the wide-angle position to the telephoto position. As can be seen from this figure, the movable lens groups L ₂ and L ₃ are displaced together by the movement of the movable barrel 12,
Although these moving distances are the same, the moving lens group L ₄ displaced by the movement of the moving frame 13 is independently displaced, and has a smaller moving distance than the moving lens groups L ₂ and L ₃ . The movement of the moving lens unit L ₄ is performed by the other side cam hole 3 provided in the cam barrel 14.
Although it can be arbitrarily determined by changing the shapes of the cam surfaces 33a, 34a of 3, 34, in reality, the cam surfaces 33a, 34a are formed so that the movement distance is determined by functional conditions. On the other hand, the focusing pinion 21 is driven by a motor included in the automatic distance measuring mechanism to rotate the rotating barrel 19 according to the helicoid screw. This rotation of the rotation barrel 19 is performed by the moving lens unit L ₂
Focusing control is performed by displacing the position of the chisel in the optical axis direction.

Further, when the rotating cylinder 19 reaches a predetermined rotating position, the swing rod is
22 hits either one of the stopper walls 11j and 11k, and the rotation of the rotation cylinder 19 is stopped.

As a result, the motor that drives the focusing pinion 21 becomes overloaded, and the switch that detects this overload stops the motor or reversely controls this motor.

When shifting from the telephoto position to the wide-angle position, the zooming pinion 35 is rotationally driven in the opposite direction. Due to this rotational drive, the cam followers 17a and 17b move to the coil spring 30.
The cam surfaces 31a, 3 of the one side cam holes 31, 32
According to 2a, the cam followers 26a and 26b are prevented from moving away from the cam surfaces 33a and 34a of the other side cam holes 33 and 34 by the expanding force of the coil spring 30 and move in the same direction as shown in FIG. The moving barrel 12 and the moving frame 13 are pushed back together. When the cam barrel 14 is rotated to the wide-angle position, the operating state shown in FIGS. 1 and 2 is obtained. Although the embodiment of the zoom lens barrel according to the present invention has been described above, the number of the ridge portions 12e provided on the movable barrel 12 can be arbitrarily increased or decreased. In this case, the concave groove formed in the fixed cylinder 11 or the moving frame 13 is defined corresponding to the convex portion 12e.

Further, although the embodiment in which the lens support frame is fixed to the rear end surface of the movable barrel has been described, the configuration of the zoom lens barrel for fixing the lens support frame to the front end surface of the movable barrel also includes the protrusion 12e. The lens support frame can be similarly fixed by utilizing the thickness. The zoom lens barrel of the present invention can be implemented in the same manner even if each of the fixed barrel, the movable barrel, and the cam barrel is made of a metal material. In this case, the moving barrel 12
The sliding portions 12c, 12d and the ridge portion 12e are integrally formed by crimping or the like, and the screw hole 12f on the rear end face is formed by machining.

Further, since the zoom lens barrel of the present invention is suitable for the configuration in which the linearly moving optical system and the non-linearly moving optical system are displaced, the master lens and the focusing lens are fixed, and The zoom lens barrel, which is widely known in the related art and has a configuration in which the zoom lens and the correction lens are moved between the lenses, can be easily implemented.

INDUSTRIAL APPLICABILITY The present invention can be used not only as a camera for taking photographs but also as a zoom lens barrel for a small-sized photographing device or a video camera.

When the zoom lens barrel of the above embodiment is used for a video camera, a diaphragm blade may be provided in the space between the moving frame 13 and the lens support frame 27 instead of the shutter blade.

Further, the present invention is implemented as a zoom lens barrel for manually operating the cam barrel 14 or the rotating barrel 19 without using the automatic zooming control mechanism linked to the pinion 35 and the automatic focusing control mechanism linked to the pinion 21. You may.

[Advantage of Invention] As described above, in the zoom lens barrel according to the present invention, the movable barrel is provided around the fixed barrel, and the cam barrel is superposed around the movable barrel. The fixed barrel is formed along the optical axis direction. Since the concave groove around the cylinder and the convex section formed on the inner surface of the moving cylinder are slidably fitted together, the movement of the moving cylinder is extremely small, and the fixed cylinder and the movable cylinder are highly coaxial. The optical axes of the optical systems provided in the fixed barrel and the movable barrel can be correctly aligned to improve the optical performance.

Also, taking advantage of the fact that the position of the ridge on the end surface of the moving cylinder becomes thick in the radial direction of the cylinder. As a result, the problem of distortion and bending of the moving barrel caused by the fixing of the lens support frame is solved, and the assembling work of the optical system becomes easy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view of a zoom lens barrel, FIG. 2 is a sectional view of the zoom lens barrel taken along the line AA in FIG. 3 is an exploded perspective view of the same zoom lens barrel, FIG. 4 is a development view of a cam barrel, and FIG.
FIG. 7 is a partial cross-sectional view showing a fixing structure of a lens support frame supported on the rear end surface of the movable barrel, FIG. 6 is a partial rear view of the movable barrel, and FIG. FIG. 3 is a cross-sectional view of the zoom lens barrel showing a state in which the zoom lens barrel is in the above state. 11 …… Fixed cylinder 11a, 11b …… Guide groove 11c, 11d …… Notch hole 11g …… Groove groove 12 …… Movement cylinder 12a, 12b …… Guide hole 12e …… Protruding ridge 12f …… Screw hole 13… … Movement frames 13a, 13b …… Circular curved surface parts 13e, 13f …… Groove groove 14 …… Cam tube 14g …… Gear parts 17a, 17b …… Cam followers 26a, 26b …… Cam followers 31, 32 …… One side cam hole 33, 34 ... Cam hole on the other side

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Numata 2800 Nagachi, Okaya City, Nagano Kyocera Stock Company President, Nookaya Plant (56) References: 57-14113 (JP, U) 179522 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A moving barrel having a cam follower that is in contact with the cam surface of the cam barrel, moves along a fixed barrel in conjunction with the rotation of the cam barrel, and positions an optical system supported by the moving barrel. In a zoom lens barrel that is configured to change and optically change the magnification, a movable barrel is superposed on a fixed barrel and a cam barrel is superposed around the movable barrel, and the optical axis of the optical system is provided on the outer surface of the fixed barrel. The inner surface of the moving cylinder, and the inner surface of the moving cylinder on which the ridges are located. A zoom lens barrel, characterized in that an outer peripheral portion of a lens support frame is brought into contact with a thick portion of the lens support to fix the support frame.