JP2004054027A - Lens barrel and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel in which deviation of a cam pin from a cam groove by the external force from an optical axis direction is more surely suppressed as compared with a conventional one and a camera in which the operation failure of members constituting the lens barrel to be caused by the external force on the lens barrel from the optical axis direction is suppressed. <P>SOLUTION: Since a tapered barrel withdraws according to the external force, the deviation of the parallel barrel from the cam groove can be prevented. According to the camera provided with such a lens barrel, the operation failure of the members of the lens barrel etc., constituting the lens barrel to be caused by the external force on the lens barrel from the optical axis direction can be suppressed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel having a member that moves in an optical axis direction via a cam mechanism, and a camera equipped with such a lens barrel.
[0002]
[Prior art]
Conventionally, a lens barrel having a cylindrical member that moves in the optical axis direction via a cam mechanism is known. In such a lens barrel, a cam member provided with a cam pin is provided with a cam groove into which the cam pin is inserted, and the driving of the cylindrical member moving in the optical axis direction is transferred from the motor. This is done by rotating a cylindrical member that is rotated around the optical axis by force.
[0003]
When an external force from the optical axis direction is applied to such a lens barrel, the external force may forcefully rotate the rotating cylindrical member provided with the cam groove. When such a situation occurs, there is a risk that a load is applied to the drive system for extending and retracting the lens barrel.
[0004]
Therefore, it is considered to provide a clutch mechanism between the cylindrical member rotated by the driving system and the driving system for rotating the rotating cylindrical member to protect the lens barrel from such external force. It has been.
[0005]
In Japanese Patent Application Laid-Open No. 9-230192, in addition to the above-described clutch mechanism, the external force from the front of the camera when the lens barrel is retracted to the wide-angle end where the clutch mechanism is no longer effective. Measures for protecting the lens barrel have been proposed. In this proposal, the lens barrel is protected from an external force by providing a protective wall for receiving the external force.
[0006]
By the way, in the lens barrel of the type in which the lens barrel is moved in the optical axis direction by the cam mechanism, since the moldability is good, a tapered cam pin (hereinafter, this tapered cam pin is referred to as a tapered piece), and this tapered piece is The cam groove to be inserted is adopted.
[0007]
Here, when an external force from the optical axis direction is applied to the lens barrel employing the cam pin having such a shape, the taper piece is detached from the cam groove before the above clutch mechanism is actuated, and the lens barrel is extended. There is a risk that it cannot be carried over.
[0008]
This is because the taper piece moves in the radial direction of the lens barrel while sliding on the tapered portion of the cam groove, that is, the inclined surface, due to an external force, and in some cases, the taper piece is detached from the cam groove.
[0009]
Therefore, although formability is reduced, a cylindrical cam pin (hereinafter, this cylindrical cam pin is referred to as a parallel piece), and a cam groove into which the parallel piece is inserted instead of a tapered piece and a cam groove into which the tapered piece is inserted It is conceivable to adopt it.
[0010]
In this way, even when an external force is applied from the optical axis direction, it is possible to prevent the slope of the cam groove from slipping out of the cam groove like a tapered piece.
[0011]
However, the cam groove into which such a parallel piece is inserted has a portion that must be tapered for molding, so that the lens barrel becomes loose and the accuracy of lens arrangement in photography This causes a problem of lowering.
[0012]
Therefore, recently, it is considered to use a tapered frame and a parallel frame together.
[0013]
FIG. 1 is a view showing a part of a cross section of a lens barrel in which a tapered frame and a parallel frame are used.
[0014]
In FIG. 1, a lens barrel is built in, and a movable lens barrel 3 that moves in the optical axis direction provided with a taper piece 31 and a parallel piece 32, and a cam groove into which the taper piece and the parallel piece are respectively fitted are provided. A rotating lens barrel 4 is shown.
[0015]
FIG. 2 is a diagram illustrating a state in which each of the tapered piece and the parallel piece shown in FIG. 1 are fitted in the cam groove.
[0016]
FIG. 2 shows an enlarged view of the tapered piece 31 and the parallel piece 32 fitted in the cam grooves 41 and 42.
[0017]
The reason why both the taper frame 31 and the parallel frame 32 are provided in this manner is to provide a taper frame to reduce backlash and prevent the lens arrangement from being lowered, and to provide a parallel frame to make it difficult to come off the cam groove. It is.
[0018]
[Problems to be solved by the invention]
FIG. 3 is a diagram showing how an external force from the front direction of the camera acts on the cam pin and the cam groove shown in FIG.
[0019]
FIG. 3 shows the action of the external force A from the front side of the camera on the movable barrel 3 and the rotary barrel 4.
[0020]
However, even in the configuration as shown in FIG. 3, when the external force A from the front direction of the camera is received, the tapered piece tries to move in the radial direction of the barrel along the slope of the cam groove. Depending on the length and the degree of backlash, it can be said that there is still a high risk that these cam pins will be disengaged from the cam groove by the component forces B and C shown in FIG.
[0021]
The above is not limited to the one provided with a clutch mechanism for protecting the drive system from an external force from the optical axis direction, and when the lens barrel is pulled or the like, It can be said that the same applies when external force is applied.
[0022]
In view of the above circumstances, the present invention includes a lens barrel in which deviation from a cam groove of a cam pin is suppressed as compared with the conventional lens barrel even when an external force from the optical axis direction is received, and such a lens barrel. Thus, an object of the present invention is to provide a camera in which the inoperability of the lens barrel constituting the lens barrel is suppressed more than ever even when an external force is applied to the lens barrel from the optical axis direction.
[0023]
[Means for Solving the Problems]
In order to achieve the above object, the lens barrel of the present invention comprises:
In a lens barrel having a member that moves in the optical axis direction via a cam mechanism,
A first member having a tapered piece whose diameter is narrowed toward the tip end in the protruding direction and a parallel piece protruding with the same diameter in the protruding direction;
A first cam groove into which the taper piece is fitted, and a second cam groove into which the parallel piece is fitted, and the taper piece, the parallel piece, the first cam groove, and the second member with respect to the first member. A second member that relatively moves via a cam mechanism comprising a second cam groove,
The taper piece is biased by a spring in the protruding direction and retracts against the spring bias according to an external force.
[0024]
In the lens barrel of the present invention, since the tapered piece protruding from the member constituting the lens barrel can be protruded and retracted according to external force, the inclined surface of the cam groove is formed because the tapered piece is fixedly protruded. Unlike the conventional case where the member moves in the radial direction of the member while sliding, the taper piece retracts when receiving an external force from the optical axis direction. Therefore, according to the lens barrel of the present invention, since the external force from the optical axis direction is not converted into the force that separates the members in the radial direction, the deviation of the cam pin from the cam groove can be suppressed more than before.
[0025]
In order to achieve the above object, the camera of the present invention comprises:
A lens barrel having a member that moves in the optical axis direction via a cam mechanism is provided, and shooting is performed by forming a subject image on a predetermined imaging plane by a shooting lens held by the lens barrel. In the camera
The lens barrel is
A first member having a tapered piece whose diameter is narrowed toward the tip end in the protruding direction and a parallel piece protruding with the same diameter in the protruding direction;
A first cam groove into which the taper piece is fitted, and a second cam groove into which the parallel piece is fitted, and the taper piece, the parallel piece, the first cam groove, and the second member with respect to the first member. A second member that relatively moves via a cam mechanism comprising a second cam groove,
The taper piece is biased by a spring in the protruding direction and retracts against the spring bias according to an external force.
[0026]
Since the lens barrel provided in the camera of the present invention has the above configuration, even if an external force from the optical axis direction is applied, the external force is not converted into a force that separates the members in the radial direction of the members. Since the deviation from the groove can be suppressed as compared with the conventional case, according to the camera of the present invention, even when an external force from the optical axis direction is applied, the lens barrel and other members constituting the lens barrel Can be prevented more than before.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the lens barrel of the present invention and the camera of the present invention will be described.
[0028]
FIG. 4 is an external perspective view of one embodiment of the camera of the present invention, including one embodiment of the lens barrel of the present invention.
[0029]
FIG. 4 shows a camera 1 which is an embodiment of the camera of the present invention, and the lens barrel 11 which is an embodiment of the lens barrel of the present invention provided in the camera 1 is extended. It is shown. The camera 1 is a digital camera with a zoom function in which the lens barrel 11 is extended and retracted between the telephoto end and the wide-angle end.
[0030]
The lens barrel 11 of the camera 1 shown in FIG. 4 includes three lens groups, which will be described in detail later. In this camera 1, the two lens groups on the front side of the camera are moved in the optical axis direction. In addition to adjusting the focal length, the focus adjustment is performed by moving the remaining one lens group in the optical axis direction.
[0031]
A flash light emission window 12 and a viewfinder objective window 13 are arranged in the upper front portion of the camera 1 shown in FIG. A shutter button 14 is disposed on the upper surface of the camera 1.
[0032]
When one of the zoom levers (not shown) of the camera 1 is pressed, the lens barrel 11 is extended to the telephoto side while the lens lever 11 is being pressed. When the other zoom lever is pressed, the lens barrel 11 is moved while the button is being pressed. Move to the wide-angle side.
[0033]
FIG. 5 is a block diagram showing a circuit configuration of the camera shown in FIG.
[0034]
The camera 1 includes the above-described photographing lens 10 including three lens groups, a CCD image pickup device 20, and a flash light emitting unit 30. A subject image formed on the CCD image pickup device 20 via the photographing lens 10 is converted into an analog image signal by the CCD image pickup device 20, and the flash light emitting unit 30 emits flash light at low illuminance.
[0035]
The camera 1 also includes an analog signal processing unit 40, an A / D unit 50, a digital signal processing unit 60, a temporary memory 70, a compression / decompression unit 80, a built-in memory (or memory card) 90, A drive circuit unit 140 is provided. The CCD image pickup device 20 is driven at a timing generated by a timing generator (not shown) in the drive circuit unit 140, and outputs an analog image signal. The drive circuit unit 140 also includes a drive circuit (not shown) for driving the photographing lens 10, the flash light emitting unit 30, and the like. The analog image signal output from the CCD image sensor 20 is analog signal processed by the analog signal processing unit 40, A / D converted by the A / D unit 50, and digital signal processed by the digital signal processing unit 60. Data representing the digital signal processed signal is temporarily stored in the temporary memory 70. The data stored in the temporary memory 70 is compressed by the compression / decompression unit 80 and recorded in the built-in memory (or memory card) 90. The data stored in the temporary memory 70 is read out to the image monitor 100, whereby an image of the subject is displayed on the image monitor 100.
[0036]
Further, the camera 1 is provided with a CPU 130 for controlling the entire camera 1, an operation switch group 110, and a shutter button 14. The operation switch group 110 is operated to set a desired photographing state. When the shutter button 14 is pressed, a picture is taken.
[0037]
Here, the photographing lens 10 shown in FIG. 5 will be described.
[0038]
6 is a cross-sectional view of the lens barrel shown in FIG.
[0039]
FIG. 6 shows a first lens group 101, a second lens group 102, and a third lens group 103 in order from the left of FIG. 6, which is the front side of the camera, and each lens group is a first lens. It is held by the frame 111, the second lens frame 112, and the third lens frame 113.
[0040]
In addition, FIG. 6 shows a moving cylinder 121 in which the first lens frame 111 is fitted. The movable cylinder 121 is provided with a tapered piece 1211 which is a tapered cam pin and a parallel piece 1212 which is a cylindrical cam pin having the same diameter in the protruding direction, and the second lens frame 112 is a tapered cam pin. A tapered piece 1121 is provided.
[0041]
Further, FIG. 6 shows a fixed cylinder 123 fixed to the camera body 1a, and a rotating cylinder provided with cam grooves 1241, 1242, 1243 in which the above-described tapered pieces 1121, 1221 and parallel pieces 1212 are fitted on the inner wall. 124 is shown.
[0042]
The fixed cylinder 123 is provided with a through hole (not shown) through which the three cam pins 1211, 1212, and 1221 described above extend while extending in parallel with the optical axis direction.
[0043]
The rotary cylinder 124 is rotatably held between the camera body 1a and a flange 1231 provided on the camera front side of the fixed cylinder 123 fixed to the camera body 1a.
[0044]
A driven gear 1244 is provided on the outer peripheral side rear end (right side in FIG. 6) of the rotating cylinder 124, and a driving force from the outside is transmitted to the rotating cylinder 124 via a gear train (not shown).
[0045]
FIG. 6 also shows a guide shaft 180 passing through the end of the third lens frame 113, a lead screw 190 screwed in an end other than the end of the third lens frame 113, and rotation. A motor 150 is shown having a shaft joined to a lead screw.
[0046]
Both ends of the guide shaft 180 are supported by the camera body 1 a and the second moving frame 122, and both ends of the lead screw 190 are supported by the camera body 1 a and the motor 150.
[0047]
Here, the operation of the lens barrel 11 will be described.
[0048]
When the rotating cylinder 124 is rotated by an angle corresponding to an operation with respect to a zoom lever (not shown), a tapered piece and a parallel piece that pass through the fixed cylinder 123 and are inserted into a cam groove provided on the inner peripheral wall of the rotating cylinder 124 are obtained. The provided moving cylinder 121 and the second lens frame 122 relatively move in the optical axis direction in accordance with the change in the optical axis direction of the cam groove. Thereafter, by driving the motor 150, the third lens frame 113 is moved in the optical axis direction to perform focusing. When the motor 150 is rotated forward, the third lens frame 113 moves in the forward direction of the camera, and when it is rotated backward, it moves in the rear direction of the camera.
[0049]
FIG. 7 is an enlarged view of a portion of the moving cylinder shown in FIG. 6 where a tapered piece is provided.
[0050]
FIG. 7A shows a tapered piece 1211, a hole 1213 formed in the movable cylinder 121, a compression spring 1200, and a stopper 1201.
[0051]
The tapered piece 1211 shown in FIG. 7 includes a head portion 1211a and a shaft portion 1211b.
[0052]
7A includes a large-diameter hole 1213a and a small-diameter hole 1213b. The upper side of the hole is the large-diameter side, and the shaft 1211b of the tapered frame is inserted together with the compression spring 1200. Has been. Only the taper piece shaft 1211b is inserted into the small diameter side below the hole, and the taper piece 121 does not come out of the hole 1213 at the end of the taper piece shaft 1211b penetrating the movable cylinder 121. A stopper 1201 is attached as described above.
[0053]
As described above, when the taper piece 1211 provided in the movable cylinder 121 receives pressure through the wall surface of the cam groove 1241 (see FIG. 6) by an external force, it is retracted as shown in FIG. When is released, it returns to its original state and can be used as a normal cam pin.
[0054]
Accordingly, the lens barrel 11 can prevent the barrel from moving in the radial direction due to the tapered piece sliding on the slope of the cam groove with respect to the external force from the optical axis direction. Deviation from the groove can be suppressed more than before. In addition, according to the camera 1 having such a lens barrel 11, it is possible to suppress that the lens barrel constituting the lens barrel becomes inoperable due to an external force applied to the lens barrel from the optical axis direction. be able to.
[0055]
【The invention's effect】
As described above, according to the lens barrel of the present invention, it is possible to suppress the deviation of the cam pin from the cam groove due to the external force from the optical axis direction. Further, according to the camera of the present invention equipped with such a lens barrel, members such as a lens barrel constituting the lens barrel become inoperable due to an external force applied to the lens barrel from the optical axis direction. Can be suppressed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a part of a cross section of a lens barrel in which a tapered frame and a parallel frame are used.
FIG. 2 is a diagram illustrating a state in which each of a tapered piece and a parallel piece shown in FIG. 1 are fitted in a cam groove.
3 is a diagram showing how an external force from the front direction of the camera acts on the cam pin and the cam groove shown in FIG. 2; FIG.
FIG. 4 is an external perspective view of one embodiment of the camera of the present invention, including one embodiment of the lens of the present invention.
5 is a block diagram showing a circuit configuration of the camera shown in FIG. 4. FIG.
6 is a cross-sectional view of the lens barrel shown in FIG. 4. FIG.
7 is an enlarged view of a portion of the first lens barrel shown in FIG. 6 where a tapered piece is erected. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Camera 1a Camera main body 2 Lens 3 Moving cylinder 31 Tapered frame 32 Parallel frame 4 Rotating cylinder 41, 42 Cam groove 10 Shooting lens 11 Lens barrel 12 Flash light emission window 13 Viewfinder objective window 14 Shutter button 20 CCD image sensor 30 Flash light emission part 40 Analog signal processing unit 50 A / D unit 60 Digital signal processing unit 70 Temporary memory 80 Compression / decompression unit 90 Built-in memory 101 First lens group 102 Second lens group 103 Third lens group 110 Operation switch group 111 First lens frame 112 First Two lens frame 113 Third lens frame 121 Moving cylinder 1121, 1221 Tapered frame 1212 Parallel frame 123 Fixed cylinder 1231 Flange 124 Rotating cylinder 1244 Driven gear 130 CPU
140 Drive circuit portion 150 Motor 180 Guide shaft 190 Lead screw 1200 Compression spring 1201 Stopper 1211a Head portion 1211b Shaft portion 1213 Hole 1213a Large diameter hole 1213b Small diameter hole

Claims (2)

In a lens barrel having a member that moves in the optical axis direction via a cam mechanism,
A first member having a tapered piece whose diameter is narrowed toward the tip end in the protruding direction and a parallel piece protruding with the same diameter in the protruding direction;
A first cam groove into which the taper piece is fitted, and a second cam groove into which the parallel piece is fitted, and the taper piece, the parallel piece, the first cam groove, and the second member with respect to the first member. A second member that relatively moves via a cam mechanism comprising a second cam groove,
2. The lens barrel according to claim 1, wherein the taper piece is biased by a spring in a protruding direction and retracts against the spring bias according to an external force. A lens barrel having a member that moves in the optical axis direction via a cam mechanism is provided, and shooting is performed by forming a subject image on a predetermined imaging plane by a shooting lens held by the lens barrel. In the camera
The lens barrel is
A first member having a tapered piece whose diameter is narrowed toward the tip end in the protruding direction and a parallel piece protruding with the same diameter in the protruding direction;
A first cam groove into which the taper piece is fitted, and a second cam groove into which the parallel piece is fitted, and the taper piece, the parallel piece, the first cam groove, and the second member with respect to the first member. A second member that relatively moves via a cam mechanism comprising a second cam groove,
The taper piece is spring-biased in a protruding direction and retracts against the spring-bias according to an external force.

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