JP2005017585A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel capable of suppressing the inclination between a rotary cylinder and a guide cylinder for reliable engagement and having improved assembly properties. <P>SOLUTION: A linearly moving tube 15 and a cam cylinder 14 are engaged so that they can be rotated relatively by first engagement sections (14d, 15f) having two engaging pawls 14d nearly symmetrically arranged with an optical axis I taken as a center, and second engagement sections (15d, 14f) that are placed at a position apart from the first engagement sections in an optical axis direction and have two locking nibs15d nearly symmetrically arranged with the optical axis I as a center. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel used for an interchangeable lens of a camera.
[0002]
[Prior art]
In lens barrels such as cameras, zoom lenses have become the mainstream, and zoom magnification has been further increased. Along with this, the rotating cylinder itself such as the cam cylinder moves in the direction along the optical axis of the photographing lens, and the lens barrel in which the guide cylinder for guiding the rotating cylinder moves in the direction along the optical axis together with the rotating cylinder. is there. In such a lens barrel, the guide tube and the rotating tube are engaged and used so as to move integrally in a direction along the optical axis while relatively rotating.
Conventionally, bayonet-type engagement has been often used for this engagement. In the case of the conventional bayonet type engagement, there are two engaging claws in order to increase the amount of rotation of the rotary cylinder as much as possible.
[0003]
[Problems to be solved by the invention]
However, in the bayonet type engagement described above, only two bayonet claws are provided with priority given to the amount of rotation, so if play occurs in the engaged portion, the gap between the rotating cylinder and the guide cylinder There is a possibility that an inclination more than twice the amount of play at the engaging portion may occur. If such an inclination occurs, there is a problem in that the optical performance is adversely affected.
[0004]
In addition, in snap-fit type engagement, the latching claws are bent and the assembly is performed, so that the assemblability is poor, the latching claws are accidentally deformed, or the engagement is easily disengaged. In some cases, stable engagement could not be obtained.
[0005]
An object of the present invention is to provide a lens barrel that can be reliably engaged while suppressing an inclination between a rotating cylinder and a guide cylinder and has good assemblability.
[0006]
[Means for Solving the Problems]
The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this. That is, the invention of claim 1 is a photographic lens (1-4), a fixed cylinder (16), and a guide cylinder that moves relative to the fixed cylinder at least along the optical axis (I) of the photographic lens. (15) and engaged with the guide tube so as to be rotatable while being regulated in the optical axis direction, and together with the guide tube in a direction along the optical axis while rotating relative to the fixed tube A rotating cylinder (14) that moves, the guide cylinder and the rotating cylinder having a first engagement member having two locking claws (14d) disposed substantially symmetrically about the optical axis. The mating portions (14d, 15f) and the first engaging portion are located at positions separated from each other in the optical axis direction, and two locking claws (15d) arranged substantially symmetrically about the optical axis. ) And the second engagement portion (15d, 14f) having That combined and a lens barrel according to claim.
[0007]
According to a second aspect of the present invention, in the lens barrel according to the first aspect, at least one of the first engagement portion (14d, 15f) and the second engagement portion (15d, 14f) is a bayonet engagement. The lens barrel is characterized in that the lens barrels are engaged with each other.
[0008]
According to a third aspect of the present invention, in the lens barrel according to the first or second aspect, the first engaging portion (14d, 15f) and the second engaging portion (15d, 14f) are: The lens barrel is characterized in that the rotational position about the optical axis is shifted.
[0009]
According to a fourth aspect of the present invention, in the lens barrel according to any one of the first to third aspects, the first engaging portion (14d, 15f) and the second engaging portion (15d). 14f) is a lens barrel characterized by being arranged so that the lines connecting the respective locking claws are substantially orthogonal.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a first embodiment of a lens barrel according to the present invention.
The lens barrel in this embodiment is a zoom lens barrel having a photographing optical system formed by the first lens group 1, the second lens group 2, the third lens group 3, and the fourth lens group 4, and a filter 5. , CCD 6, CCD reference plate 7, electric substrate 8, first group cylinder 9, front ring 10, second group cylinder 11, shutter unit 12, third group cylinder 13, cam cylinder 14, rectilinear cylinder 15, fixed cylinder 16, motor 17, A fourth group cylinder 18, first group cylinder follower pins 19a and 19b, a guide shaft 20, a base plate 21, a second group cylinder follower pin 22 and the like are provided.
[0011]
The first group cylinder 9 is a member that indicates the first lens group 1, has follower pins 19 a and 19 b on the outer periphery, and is cam-coupled to the cam cylinder 14. A front ring 10 is screwed to the subject side of the first group cylinder 9.
[0012]
The second group cylinder 11 is a member that supports the second lens group 2 and is guided by the guide shaft 20 so as to be movable in a straight line. A second group cylinder follower pin 22 is implanted therein.
[0013]
The shutter unit 12 is a mechanism that transmits / blocks photographing light between the second lens group 2 and the third lens group 3, and is fixed to the third group cylinder 13.
[0014]
The third group cylinder 13 is a member that supports the third lens group 3 and the shutter unit 12. The third group cylinder 13 can be moved in the direction along the optical axis I by an adjustment mechanism (not shown) with respect to the rectilinear cylinder 15, but after the adjustment, the third group cylinder 13 moves integrally with the rectilinear cylinder 15.
[0015]
The cam cylinder 14 is a rotating cylinder that fits in a helicoid manner with the fixed cylinder 16 and moves straight while obtaining rotational force from a drive mechanism (not shown). One end of the cam cylinder 14 has a bayonet portion, which will be described later, engages with the straight cylinder 15 and bayonet, and moves in the optical axis direction as a unit.
Further, first group cam grooves 14 a and 14 b are provided on the inner side of the cam cylinder 14, and engage with first group cylinder follower pins 19 a and 19 b fixed on the outer side of the first group cylinder 9, respectively.
Further, the cam cylinder 14 is provided with a second group cam groove (not shown) and is engaged with the second group cylinder follower pin 22.
[0016]
The rectilinear cylinder 15 is a guide cylinder that is provided on the inner peripheral side of the cam cylinder 14 and moves in a direction along the optical axis with respect to the fixed cylinder 16.
The rectilinear cylinder 15 has two convex portions 15g on the outer periphery, and is engaged with a rectilinear guide groove (not shown) provided on the inner periphery of the fixed cylinder 16, so that the cam cylinder 14 follows the helicoid. When moving in the solid axis direction while rotating, the rectilinear cylinder 15 does not rotate but only moves rectilinearly.
Further, the rectilinear cylinder 15 guides the first group cylinder 9 to perform only rectilinear movement.
Further, a guide shaft 20 and a guide shaft (not shown) other than the guide shaft are fixed to the rectilinear cylinder 15. The guide shaft 20 guides the second group cylinder 11 straightly, and a guide shaft (not shown) stops the rotation of the second group cylinder 11.
[0017]
The fixed cylinder 16 is screwed to the base plate 21. A helicoid 16a is formed on the inner periphery of the fixed cylinder 16, and is in a helicoid fit with a helicoid 14g on the outer side of the cam cylinder 14 on the inner side.
[0018]
The motor 17 is a driving source that generates a driving force for driving the lens group when performing autofocus driving, and is fixed to the base plate 21.
[0019]
The fourth group cylinder 18 supports the fourth lens group 4 and is moved by the motor 17 in the optical axis direction by a mechanism (not shown) to perform focusing.
[0020]
The first group cylinder follower pins 19a and 19b are implanted in the first group cylinder 9, engage with the first group cam grooves 14a and 14b of the cam cylinder 14, and move along the cam groove as the cam cylinder 14 rotates. Do.
[0021]
The base plate 21 is a member to which the fixed cylinder 16 is fixed. Further, the base plate 21 supports the filter 5, and on the back side of the base plate 21, the CCD 6, the CCD reference plate 7, and the electric substrate. 8 is integrally fixed.
[0022]
The second group cylinder follower pin 22 is implanted in the second group cylinder 11, engages with the cam groove of the cam cylinder 14, and moves along the cam groove as the cam cylinder 14 rotates.
[0023]
Next, bayonet engagement between the cam cylinder 14 and the rectilinear cylinder 15 will be described.
FIG. 2 is a perspective view showing the cam cylinder 14 and the rectilinear cylinder 15. In FIG. 2, a part of the shape is omitted for simplicity.
The bayonet portion of the cam cylinder 14 is provided with two locking claws 14d in a substantially diagonal direction and two cutout portions 14e in a direction in which the locking claw 14d has a tolerance of approximately 90 °.
Further, the bayonet portion of the straight cylinder 15 is provided with two notches 15c in a substantially diagonal direction and two locking claws 15d in a direction in which the notch 15c has a tolerance of about 90 °. .
[0024]
When the rectilinear cylinder 15 is inserted into the cam cylinder 14 in the direction of the arrow in FIG. 2, the locking claw 14d passes through the notch 15c, and the locking claw 15d passes through the notch 14e, The flange surface 14h of the cylinder 14 and the flange surface 15e of the rectilinear cylinder 15 are in contact with each other (state shown in FIG. 1).
When the cam cylinder 14 is rotated with respect to the rectilinear cylinder 15 in this state, the locking claw 14d engages with the flange surface 15f. The locking claw 15d is engaged with the flange surface 14f. Therefore, the rectilinear cylinder 15 and the cam cylinder 14 are integrated in the optical axis direction and cannot be detached. In the operating state of the camera, the bayonet is always locked.
[0025]
Thus, in the present embodiment, the first engaging portion (14d, 15f) having the two locking claws 14d disposed substantially symmetrically about the optical axis I, and the first engaging portion Is provided in the position away from the optical axis, and the second engaging portions (15d, 14f) having the two locking claws 15d disposed substantially symmetrically about the optical axis are provided. Since the four locking claws are always engaged and these are arranged in a substantially orthogonal direction, it is difficult for the rectilinear cylinder 15 to fall (tilt) with respect to the cam cylinder 14.
Note that the first engaging portion (14d, 15f) and the second engaging portion (15d, 14f) are arranged at positions separated in the direction along the optical axis I, and thus this embodiment. A plurality of engaging portions can be arranged as described above.
[0026]
In the lens barrel in this embodiment, when the cam barrel 14 moves in the optical axis direction simultaneously with the rotation, the rectilinear barrel 15 moves in the optical axis direction without rotating.
Further, since the straight cylinder 15 guides the first group cylinder 9 and the second group cylinder 11 linearly, when the cam cylinder 14 rotates, the first group cylinder 9 and the second group cylinder 11 move in the optical axis direction by the action of the cam. To do.
Further, the third group cylinder 13 moves integrally with the rectilinear cylinder 15. The zoom operation is performed by the above operation.
Furthermore, the fourth group cylinder 18 is moved in the optical axis direction by a mechanism (not shown) to perform focusing.
[0027]
In the present embodiment, a first engagement portion (14d, 15f) formed by two locking claws 14d and a flange surface 15e disposed substantially symmetrically about the optical axis, and a first engagement The second engaging portion (15d, 15d, 15d) formed by two engaging claws 15d and flange surfaces 14f that are located in a position separated from each other in the optical axis direction and are substantially symmetrically arranged around the optical axis. 14f). Further, the line connecting the two locking claws 14d of the first engaging portion and the line connecting the two locking claws 15d of the second engaging portion are arranged so as to be substantially orthogonal. Therefore, the inclination between the rotating cylinder and the guide cylinder can be minimized, and the rotation angle between the cam cylinder 14 and the rectilinear cylinder 15 can be increased. Further, since the engagement is a bayonet system, the assemblability can be improved.
[0028]
(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
For example, in the present embodiment, an example in which the present invention is applied to a lens barrel having a four-group configuration has been described. However, the present invention is not limited thereto, and other lens group configurations such as a three-group configuration may be used.
[0029]
Moreover, in this embodiment, although the 1st engaging part and the 2nd engaging part showed the example which all engage by a bayonet system, it is not restricted to this, For example, one side is a snap fit system You may make it engage.
[0030]
Furthermore, in the present embodiment, the first engaging portion and the second engaging portion are provided behind the lens barrel (on the side close to the CCD). One or both may be provided in front of the lens barrel (subject side).
[0031]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained.
(1) The guide tube and the rotating tube are a first engaging portion having two engaging claws disposed substantially symmetrically about the optical axis, and the first engaging portion is in the optical axis direction. Since the second engaging portion having two locking claws disposed substantially symmetrically with respect to the optical axis is relatively rotatably engaged with the guide, Engagement can be ensured while suppressing the inclination between the tube and the rotating tube.
[0032]
(2) Since at least one of the first engaging portion and the second engaging portion is engaged by bayonet engagement, the assemblability can be improved.
[0033]
(3) Since the first engaging portion and the second engaging portion are arranged with their rotational positions about the optical axis being shifted, the inclination between the guide tube and the rotating tube is further increased. It can be effectively suppressed.
[0034]
(4) Since the first engaging portion and the second engaging portion are arranged so that the lines connecting the respective locking claws are substantially orthogonal to each other, the inclination between the guide tube and the rotating tube is set. Can be minimized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a lens barrel according to the present invention.
FIG. 2 is a perspective view showing a cam cylinder 14 and a rectilinear cylinder 15;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 3 3rd lens group 4 4th lens group 5 Filter 6 CCD
7 CCD reference plate 8 Electric board 9 1st group cylinder 10 Front ring 11 2nd group cylinder 12 Shutter unit 13 3rd group cylinder 14 Cam cylinder 14d Locking claw 14e Notch part 14f, 14h Flange surface 15 Straight cylinder 15c Notch part 15d Clasps 15e, 15f Flange surface 16 Fixed cylinder 17 Motor 18 4th group cylinder 19a, 19b 1st group cylinder follower pin 20 Guide shaft 21 Base plate 22 2nd group cylinder follower pin

Claims (4)

A taking lens,
A fixed cylinder;
A guide tube that moves at least in a direction along the optical axis of the photographing lens with respect to the fixed tube;
A rotating cylinder that engages with the guide cylinder so as to be rotatable while being regulated in the optical axis direction, and moves with the guide cylinder in a direction along the optical axis while rotating relative to the fixed cylinder; ,
With
The guide tube and the rotating tube are
A first engaging portion having two locking claws disposed substantially symmetrically about the optical axis;
The first engaging portion is a second engaging portion having two locking claws disposed substantially symmetrically about the optical axis at a position separated in the optical axis direction;
Engaged in a relatively rotatable manner,
A lens barrel characterized by The lens barrel according to claim 1,
At least one of the first engagement portion and the second engagement portion is engaged by bayonet engagement;
A lens barrel characterized by In the lens barrel according to claim 1 or 2,
The first engaging portion and the second engaging portion are arranged with their rotational positions about the optical axis shifted,
A lens barrel characterized by The lens barrel according to any one of claims 1 to 3, wherein
The first engaging portion and the second engaging portion are arranged so that the lines connecting the respective locking claws are substantially orthogonal;
A lens barrel characterized by

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