JPH09203842A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel which is smoothly extended and contracted. SOLUTION: In a 1st range, cam follower pins 90 and 40 engage with cam grooves 6d and 6c of an intermediate cylinder 6 and then a 2-group lens 3 and a 3-group lens 4 are driven by a cam along the optical axis associated with the rotation of the intermediate cylinder 6. In a 2nd range, the cam follower pins 90 and 40 and the cam grooves 6d and 6c of the intermediate cylinder 6 are disengaged from each other and the 2-group lens 3 and 3-group lens 4 are driven along the optical axis by a 1st-group cylinder 8 and a compression spring 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel of a camera.

[0002]

2. Description of the Related Art A zoom lens barrel can take a telephoto end position where the lens barrel is fully extended and a wide angle end position where the lens barrel is extended, depending on the extended state of the lens barrel. In such a zoom lens barrel, a plurality of lens groups are moved in the optical axis direction by cams and helicoids in the lens drive range (hereinafter referred to as the zoom range) from the wide-angle end position to the telephoto end position. Also, for example,
There is also a combination of helicoid drive and cam drive so that one lens group is driven by a helicoid and the other lens group is driven by a cam. Furthermore, in a camera in which the zoom lens barrel can take the retracted position further retracted from the wide-angle end position, the movement of the lens group in the lens drive range (hereinafter referred to as the retractable range) from the wide-angle end position to the retracted position is cammed. There are many things done by 2. Description of the Related Art In recent years, the number of lenses has increased with the increase in magnification of photographing lenses of cameras, and the configuration has become complicated. Since the number of lens groups increases accordingly, the number of cam grooves for cam-driving the lens groups also increases.

[0003]

By the way, in the lens barrel which moves the lens group to the retracted position by the cam drive,
The profile (inclination or shape) of the cam groove may change greatly depending on the zoom range and the collapsible range, and thus the load on the drive system may change greatly and smooth operation may not be achieved.

An object of the present invention is to provide at least one lens group.
It is to provide a lens barrel of a camera having two smooth lens barrels that can be smoothly extended and retracted.

[0005]

Means for Solving the Problems An explanation will be given with reference to FIGS. 1, 3, 4 and 6 showing an embodiment. Referring to FIG. 1, the lens barrel according to the invention of claim 1 has lens groups 3 and 4 provided in a cam barrel 6 so as to be movable in the optical axis direction, and a cam formed in the cam barrel 6. Grooves 6d, 6c
And cam follower pins 90 provided on the lens groups 3 and 4,
By engaging with 40, a cam mechanism that drives the lens groups 3 and 4 in the optical axis direction as the cam barrel 6 rotates, and a drive that drives the lens groups 3 and 4 in the optical axis direction separately from the cam mechanism. Means 8 and 10, and the moving range of the lens groups 3 and 4 in the optical axis direction is as follows: (a) First cam driven by the cam mechanism
And (b) the cam follower pins 90, 40 and the cam grooves 6d, 6c of the cam barrel 6 are disengaged, and the lens groups 3, 4
And the second range driven by the driving means 8 and 10 in the optical axis direction achieves the above-mentioned object. FIG.
In the lens barrel according to the second aspect of the present invention, the cam grooves 6d and 6c have the second position corresponding to the second range from the first position corresponding to the first range of the cam cylinder 6. Of the grooves (61d, 62
d) and (61c, 62c), the groove width at the second position is made larger than the groove width at the first position so that the engagement with the cam follower pins 90, 40 is released. In the lens barrel according to the invention of claim 3, the cam groove 62c is formed so that the groove width at the second position becomes larger as it goes away from the first position. Referring to FIG. 6, in the lens barrel according to the invention of claim 4, the cam groove 61 is provided.
c and 62c are substantially U-shaped grooves composed of bottom surfaces 612c and 622c and two side surfaces (611c, 621c) and (621c, 622c), and the side surface 621c of the cam groove 62c at the second position. The angle between the bottom surface 622c and the side surface 611c of the cam groove 61c at the first position is set to be larger than the angle between the bottom surface 612c.
Explaining in association with FIG. 2 and FIG. 4, the lens barrel according to the invention of claim 5 further includes another lens optical system 4 adjacent to the lens group 3 in the optical axis direction, and is provided in the lens group 3. Even when the cam follower pin 90 comes into contact with the side wall surface of the lens optical system 4 of the cam groove 62d formed at the second position, the lens groove 3 is maintained in the non-contact state with the lens optical system 4. 62d has been set. With reference to FIG. 1, in the lens barrel according to the invention of claim 6, the first range is a zoom range in which the camera can photograph, and the second range is that the lens groups 3 and 4 are inside the camera 1. It is the range of collapse that is carried over to.

The lens barrel according to the invention of claim 1 is the first lens barrel.
In the range, the cam follower pins 90, 40 and the cam grooves 6d, 6c of the cam barrel 6 are engaged with each other, whereby the lens groups 3 and 4 are cam-driven in the optical axis direction in conjunction with the rotation of the cam barrel 6. , In the second range, the cam follower pin 9
0, 40 and the cam grooves 6d, 6c of the cam barrel 6 are disengaged, and the lens groups 3, 4 are driven in the optical axis direction by the driving means 8, 10. Here, the term "disengaged" means that the cam follower pin is in contact with the groove side surface of the cam groove, and the cam follower pin is not in contact with the groove side surface due to a gap. For example, even when the cam follower pin is housed in the cam groove, the engagement is disengaged in the above-described state.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to the embodiment.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a camera including a zoom lens barrel according to the present invention. Reference numeral 1 is a camera, and 1a is a body of the camera 1. The zoom lens barrel is a straight group barrel 5 holding a dark box 2, a second group lens 3 and a third group lens 4 fixed to the camera body 1b, a first group barrel holding an intermediate barrel 6 and a first group lens 7. It is composed of 8. The second group lens 3 is composed of three lenses.

FIG. 2 is an exploded perspective view showing a lens barrel portion. A female helicoid 2a and a straight guide groove 2b are formed on the inner circumference of the dark box 2. A guide portion 5 that engages with the straight guide groove 2b of the dark box 2 is provided at the end of the straight box 5 on the dark box side.
b is formed. Three guide grooves 51a and 52a are alternately formed on the inner circumference of the straight-moving cylinder 5 along the optical axis, and the bottoms of the guide grooves 51a and 52a each have a length that penetrates the straight-moving cylinder 5 in the outer peripheral direction. Each hole 5c is formed.

On the outer periphery of the lens chamber 4c of the third group lens 4, three guide portions 4a which engage with the guide groove 51a of the rectilinear barrel 5 are provided.
And each guide portion 4a is provided with a hole 4b into which the cam follower pin 40 is implanted. Also, 2
The lens chamber 9 of the group lens 3 is provided with three guide portions 9a, and a hole 9b into which the cam follower pin 90 is implanted is formed in each guide portion 9a. The lens chamber 4c has a straight-moving barrel 5 so that the guide portion 4a and the guide groove 51a are engaged with each other.
Hole 5d formed at the end of the long hole 5c after being stored in
Through the cam follower pin 40 through the hole 4b in the guide portion 4a.
Planted in. Similarly, the guide portion 9a and the guide groove 52a
After the second lens group 3 is housed in the straight-moving barrel 5 so that and engage with each other, the cam follower pin 90 is planted in the hole 9b of the guide portion 9a through the hole 5d. 10 is the second lens group 3 and 3
It is a compression spring arranged between the second lens group 3 and the third lens group 4, and urges the second lens group 3 and the third lens group 4 in directions to separate from each other.

A male helicoid 6a that engages with the female helicoid 2a of the dark box 2 is formed on the outer circumference of the intermediate cylinder 6, and a female helicoid 6b and cam grooves 6c and 6d are formed on the inner circumference (see FIG. 1).
Are formed respectively. The intermediate barrel 6 is externally inserted into the straight-moving barrel 5 in which the second group lens 3 and the third group lens 4 are housed, and the groove 6g of the intermediate barrel 6 and the flange portion 5g of the straight-travel barrel 5 are engaged with each other, whereby the intermediate barrel 6 Is rotatably attached to the straight advancement cylinder 5. At that time, the cam follower pin 90 of the second group lens
Is attached to the cam groove 6d of the intermediate cylinder 5, and the cam follower pin 40 of the third lens group is attached to the cam groove 6c of the intermediate cylinder 6. A male helicoid 8b that engages with the female helicoid 6b of the intermediate barrel 6 is formed on the outer periphery of the first group barrel 8,
A guide portion (not shown) that engages with a guide groove 5e formed in the outer circumference of the rectilinear barrel 5 in the optical axis direction is provided on the inner circumference. The first group cylinder 8 is attached to the intermediate cylinder 6 such that the male helicoid 8b engages with the female helicoid 6b of the intermediate cylinder 6 and the guide portion (not shown) engages with the guide groove 5e of the rectilinear barrel 5. Reference numeral 8a is a pin receiving portion with which the cam follower pin 90 contacts when the first group lens 7 moves to a predetermined position, while reference numeral 8c is a nib for avoiding interference with the cam follower pin 40. Pin receiving portion 8a and niger 8c
Are provided alternately three by three.

The intermediate cylinder 6 is moved to the dark box 2 by a driving device (not shown).
When rotated with respect to, the intermediate cylinder 6 moves in the optical axis direction by the helicoids 2a and 6a. The straight barrel 5 is an intermediate barrel 6
Since the guide portion 5b is rotatably attached to the dark box 2 and engages with the straight guide groove 2b of the dark box 2, it moves in the optical axis direction without rotating with respect to the dark box 2. Therefore, the intermediate barrel 6, the second lens group 3 and the third lens group 4 move integrally in the optical axis direction, and the cam follower pins 40 and 90 are cam-driven by the cam grooves 6c and 6d, respectively. The third and third group lenses 4 move relative to the intermediate barrel 6 in the optical axis direction. On the other hand, the first group cylinder 8 provided with a guide portion that engages with the guide groove 5e of the straight-moving cylinder 5.
Moves linearly in the optical axis direction by the helicoids 6b and 8b as the intermediate cylinder 6 rotates.

FIGS. 3 to 5 are views for explaining the relationship between the cam follower pin, the cam groove and the like. With reference to FIGS. 2 to 5, the zoom lens barrel from the state extended to the zoom range to the collapsed position is shown. The operation will be described. 3 to 5, the upper side of the figure is the subject side, and the lower side of the figure is the camera body side. FIG. 3 is a development view showing the cam grooves 6c and 6d formed on the inner circumference of the intermediate cylinder 6. The cam groove 6c includes a groove 61c in the zoom range and a groove 62c in the retracted range.
1c is formed to have a groove width that engages with the cam follower pin 40. On the other hand, since the groove width of the groove 62c is formed larger than the groove width of the groove 61c, a gap is generated between the cam follower pin 40 and the side surface of the groove 62c, and the cam follower pin 40 is in the groove 62c. They are out of engagement with each other. Similarly, the cam groove 6d corresponds to the grooves 61d and 62.
The groove width of the groove 62d is larger than that of the groove 61d, and the cam follower pin 90 and the cam groove 6d are formed.
The relationship is the same.

40A-40E and 90A-90E are
The positions of the cam follower pins 40 and 90 in different extended states of the zoom lens barrel are shown. 40A and 90A show a state in which the zoom lens barrel is maximally extended toward the subject, that is, the telephoto end position of the zoom range is set to 4
Reference numerals 0B and 90B respectively indicate wide-angle end positions of the zoom range. When the intermediate cylinder 6 is rotated by a predetermined value in the direction A in the figure by a drive device (not shown), the cam follower pins 40 and 90 are cam-driven by the cam grooves 6c and 6d, respectively, and the telephoto end positions 40A of the grooves 61c and 61d. , 90A
To the wide-angle end positions 40B and 90B. When the cam follower pin 40 of the third lens group 4 moves to the wide-angle end position 40B, as shown in FIG. 4, which is an enlarged view of the portion surrounded by the alternate long and short dash line B in FIG. 3, the cam follower pin 40 moves straight.
The end portion 5f (indicated by a chain double-dashed line) of the elongated hole 5c formed in is contacted. On the other hand, the first lens group 8 includes the helicoids 6b and 8b.
Moves relative to the intermediate barrel 6 in the direction of the camera body, and when the cam follower pin 90 of the second lens group 3 reaches the wide-angle end position 90B, the pin receiving portion 8a of the first lens group 8 (shown by a chain double-dashed line). ) Contacts the cam follower pin 90.

When the first group barrel 8 moves toward the camera body due to the rotation of the intermediate barrel 6, the second group lens 3 has the cam follower pin 90 in contact with the pin receiving portion 8a. The cam follower pin 90 moves in the main body direction to the collapse start position 90C of the groove 62d, and the engagement between the cam follower pin 90 and the cam groove 62d is released.
On the other hand, in the third lens group 4, the cam follower pin 40 has the straight-moving barrel 5.
Since it is in contact with the end 5f of the elongated hole 5c formed in
It moves in the direction of the camera body together with the straight-moving barrel 5 and the intermediate barrel 6. At this time, the intermediate barrel 6 rotates relative to the rectilinear barrel 5 and the third lens group 4, so that the cam follower pin 40 moves on the inner peripheral surface of the intermediate barrel 6 in the circumferential direction. That is, the cam follower pin 40 moves from the wide-angle end position 40B of the groove 61c to the collapse start position 40C of the groove 62c, and the engagement between the cam follower pin 40 and the cam groove 62c is released.

As shown in FIG. 1, second group lenses 3 and 3
The group lenses 4 are biased by springs 10 in a direction away from each other, that is, the second group lens 3 is biased toward the subject and the third group lens 4 is biased toward the camera body. for that reason,
The pin receiving portion 8a of the first group barrel 8 and the cam follower pin 90 are kept in contact with each other, and the end 5f of the elongated hole 5c of the rectilinear barrel 5 and the cam follower pin 40 are kept in contact with each other. As a result, when the intermediate barrel 6 is further rotated, the third group lens 4, the rectilinear barrel 5 and the intermediate barrel 6 move integrally in the camera body direction, and the second group lens 3 and the first group barrel 8 move to the intermediate barrel 6. In contrast, it moves relative to the camera body. afterwards,
Cam follower pins 40 and 90 are in positions 40D and 9
When it reaches 0D, the third lens group 4 comes into contact with the camera body and stops. However, since the intermediate barrel 6 is further rotated and the rectilinear barrel 5 and the intermediate barrel 6 move integrally in the camera direction, the third group lens 4 relatively moves in the object direction with respect to the intermediate barrel 6, and the cam follower pin 40 rectilinearly moves. The tube 5 is separated from the end 5f of the elongated hole 5c. Thereafter, when the cam follower pins 40 and 90 reach the retracted positions 40E and 90E, the rotation of the intermediate cylinder 6 is stopped.

In FIG. 4, two-dot chain lines 41 and 91 show the loci of the cam follower pins 40 and 90 in the retracted range. In the retracted range, the cam follower pin 90 is in contact with the pin receiving portion 8a of the first group barrel 8, so that the locus 91
Is a straight line, and the angle between the plane perpendicular to the optical axis is the helicoid 6
It is equal to the lead angle of b and 8b. On the other hand, in the case of the trajectory 41,
Since the third group lens 4 and the intermediate barrel 6 move integrally between the positions 40C and 40D, the locus 41 is a straight line in the circumferential direction of the intermediate barrel 6. Also, from position 40D to position 40E
During this period, the stopped third group lens 4 moves in the direction of the subject relative to the intermediate barrel 6 that moves in the direction of the camera body, and the locus 41 tilts toward the subject. FIG.
FIG. 6 is a diagram showing a relationship among the cam follower pins 40 and 90, the cam grooves 6c and 6d, the elongated hole 5c of the straight-moving barrel 5 and the like at the retracted position. In this state, the long hole 5 formed in the straight advancement cylinder 5
The end 5f of c is located near the cam follower pin 90.

In this way, the retraction of the zoom lens barrel is completed. On the contrary, when the zoom lens barrel is extended from the retracted position to the zoom range, the above operation is performed in reverse. In this case, in the retracted range, the third lens group 4 is provided with the spring 10
Is pressed against the camera body by the urging force of the
The group lens 3 is driven toward the subject by the urging force of the spring 10.

By the way, d1 and d2 shown in FIG. 4 are cam follower pins 40 and 9 at positions 40D and 90D, respectively.
The distance between 0 and the side surfaces of the grooves 62c and 62d is shown.
It is also the distance over which the group lens 3 and the third group lens 4 can move against the biasing force of the spring 10. In the embodiment of the present invention, the sum (d1 + d2) of d1 and d2 is the second lens group 3 and the third lens group 4 in the entire retractable range.
Is set smaller than the interval. Therefore, there is no risk of the second lens group 3 and the third lens group 4 interfering with each other when a shock is applied to the lens barrel.

When the third lens group 4 is displaced in the optical axis direction when the lens barrel is extended, the cam follower pin 40 interferes with the side surface of the groove 62c depending on the shape of the groove 62c, so that the smooth extension operation can be achieved. May be disturbed. However, in the embodiment of the invention described above, the groove 62 in the collapsing range is
Since the groove width of c is formed so as to gradually increase from the position 40C to the position 40E, even if the cam follower pin 40 comes into contact with the side surface of the groove 62c at the time of paying out, a smooth payout operation is performed. It can be carried out.

FIG. 6 is a view showing the relationship between the cam groove 6c formed on the inner circumference of the intermediate cylinder 6 and the cam follower pin 40. As shown in FIG.
FIGS. 6A and 6B show a cross section of the groove 61c in the zoom range and a cross section of the groove 62c in the collapsible range according to the embodiment of the present invention. The angle between the side surface 611c of the groove 61c and the groove bottom surface 612c is formed to be equal to the angle of the tip end inclined surface 40a of the cam follower pin 40 to be engaged, but the side surface 621c of the groove 62c and the groove bottom surface 6 in the collapsed range.
The angle with respect to 22c is set larger than the side surface 611c of the zoom range. On the other hand, FIG.
The angle between the groove bottom surface 102 and the groove bottom surface 102 is the side surface 611 of FIG.
It is a figure which shows the case where it is equal to the angle between c and the groove bottom face 612c. When the intermediate cylinder 6 is manufactured by molding using a slide mold, if a groove is formed as shown in FIG. 6C, the mold must be moved toward the center of the cylinder when the inner split mold is removed. The type itself becomes complicated. However, when the groove 62c is formed as shown in FIG. 6B, the draft of the mold is free, which is advantageous in that the structure of the inner split mold is simplified.

The embodiment of the invention described above has the following advantages over the conventional lens barrel. (1) When the amount of movement of the lens group greatly differs between the zoom range and the collapsible range, in the case where only the cam drive is used as in the conventional case, the inclination of the cam groove greatly changes between the zoom range and the collapsible range, and the lens There is a possibility that the feeding operation may not be performed smoothly. However, in the above-described embodiment, the engagement between the groove 61d of the cam groove 6d and the cam follower pin 90 and the engagement between the groove 61c of the cam groove 6c and the cam follower pin 40 are disengaged and the intermediate cylinder 6 is disengaged from each other in the collapsed range. Since the movement of the second group lens 3 in the optical axis direction is performed by another driving means different from the cam driving, that is, the driving force of the first group barrel 8 and the urging force of the compression spring 10, the zoom range to the collapsible range and the collapsible range. The operation from to the zoom range is smoothly performed. (2) When the lens barrel is extended, the cam follower pin 40
Even if the groove contacts the side surface of the groove 62c, the groove width of the groove 62c in the collapsed range is formed so as to gradually increase from the position 40C to the position 40E. It is possible to perform a payout operation. (3) There is no risk of the second lens group 3 and the third lens group 4 interfering with each other when a shock is applied to the lens barrel. (4) When the intermediate cylinder 6 is manufactured by molding using a slide mold, since the draft of the mold is free, there is an advantage that the structure of the inner split mold is simplified.

In the embodiments of the invention described above, the zoom lens barrel has been described, but the present invention can also be applied to a lens barrel capable of two focal points, a wide angle and a telephoto. Further, in the retracted range, the cam follower pin 90 is brought into contact with the pin receiving portion 8a of the first group barrel 8 to drive the second group lens 3 toward the camera body. However, other driving means such as direct driving by a motor may be used. You may use.

In the correspondence between the embodiment of the invention described above and the scope of the claims, the intermediate cylinder 6 constitutes the cam cylinder, the first group cylinder 8 and the compression spring 10 respectively constitute the driving means.

[0025]

As described above, in the conventional lens barrel which drives the lens group only by driving the cam, when the inclination of the cam grooves in the first and second ranges changes significantly, Although there is a possibility that the delivery and retraction operation of the cylinder is not performed smoothly, according to the present invention, in the first range, the cam follower pin and the cam groove engage with each other to cam drive the lens group, and in the second range. Since the cam follower pin and the cam groove are disengaged from each other and the lens unit is driven by a driving means different from the cam driving, the feeding and feeding operation between the first and second ranges can be smoothly performed. In particular, claim 3
In the invention, since the groove width of the cam groove in the second range is formed so as to increase from the boundary portion with the first range to the groove end portion on the opposite side, the cam follower pin is formed in the cam groove when the lens barrel is extended. Even if it touches the side of
The lens barrel can be smoothly extended.

[Brief description of drawings]

FIG. 1 is a sectional view of a camera including a lens barrel according to the present invention.

FIG. 2 is an exploded perspective view showing a lens barrel.

FIG. 3 is a development view of an inner peripheral surface of an intermediate cylinder 6 for explaining a relationship between a cam follower pin, a cam groove, and the like.

FIG. 4 is an enlarged view of portion B in FIG.

FIG. 5 is an intermediate chamber 6 when the lens barrel is in the retracted position.
It is the figure which overlapped and showed the development view of and the development view of the straight advancement cylinder 5.

FIG. 6 is a sectional view showing a relationship between a cam groove and a cam follower pin.

[Explanation of symbols]

 1 camera 1a body 1b camera body 3 2nd group lens 4 3rd group lens 5 rectilinear barrel 6 intermediate barrel 6c, 6d cam groove 7 1st group lens 8 1st group barrel 10 compression spring 40, 90 cam follower pin

Claims (6)

[Claims] 1. A lens group provided in the cam barrel so as to be movable in the optical axis direction, and a cam groove formed in the cam barrel and a cam follower pin provided in the lens group are engaged with each other, thereby allowing the cam barrel to move. A cam mechanism that drives the lens group in the optical axis direction with rotation, and a drive unit that drives the lens group in the optical axis direction separately from the cam mechanism, and a moving range of the lens group in the optical axis direction. Is (a) a first range cam-driven by the cam mechanism, and (b) the cam follower pin is disengaged from the cam groove of the cam barrel, and the lens group is moved in the optical axis direction by the driving means. A lens barrel comprising: a second range to be driven. 2. The lens barrel according to claim 1, wherein the cam groove has a first position corresponding to the first range of the cam cylinder and a second position corresponding to the second range. The lens mirror is characterized by comprising a groove formed continuously over the width, and the groove width at the second position is made larger than the groove width at the first position so as to be disengaged from the cam follower pin. Cylinder. 3. The lens barrel according to claim 2, wherein the cam groove is formed such that the groove width at the second position becomes wider as the distance from the first position increases. Cylinder. 4. The lens barrel according to claim 2 or 3, wherein the cam groove is a substantially U-shaped groove having a bottom surface and two side surfaces, and the cam at the second position. A lens barrel, wherein an angle between the side surface and the bottom surface of the groove is larger than an angle between the side surface and the bottom surface of the cam groove at the first position. 5. The lens barrel according to claim 2, further comprising another lens optical system adjacent to the lens group in the optical axis direction, wherein a cam follower pin provided in the lens group is The second
The cam groove is defined such that the lens group maintains a non-contact state with the lens optical system even when the cam groove formed at the position abuts the side wall surface of the lens optical system. A lens barrel to be used. 6. The lens barrel according to claim 1, wherein the first range is a zoom range in which an image can be taken by a camera, and the second range is the lens group in the camera. A lens barrel for a camera, characterized in that it is within the retractable range.