JP2003255212A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel which is miniaturized and made compact and where a frame member is surely driven to reciprocate. <P>SOLUTION: A lens frame 20 has female helicoids 2d and 2e, cam grooves 2f and 2g in a crossing state with the helicoid 2e and a bayonet groove 2n on the inner peripheral surface of a cam frame 2, and three helicoid insertion parts 2h in which a male helicoid 3b is inserted, and three pairs of bayonet pawl insertion parts 2i and 2j and 2i' and 2j' are provided at the rear end wall part 2q of the cam frame 2. The insertion parts 2i and 2i' are superposed and arranged in the insertion part 2h where the pawl is apt to come off. When the insertion parts 2i and 2i' exist inside the insertion part 2h, they are set to be positioned on the outside of the insertion part 2h to prevent the disengagement of the bayonet pawl. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, there is a conventional lens barrel shown in a vertical sectional view of FIG. 10 as a lens barrel having a cam frame which can be rotated and moved forward and backward, and a lens frame which is driven forward and backward by the cam frame. This conventional lens barrel 50 includes a fixed frame 51,
A second group frame that movably supports a cam frame 52, a first group frame (hereinafter, referred to as a first group frame) 53 that holds the first group lens 65, and a lens frame 59 that holds the second group lens 66. (Hereinafter, referred to as a second group frame) 54, a third group frame (hereinafter, referred to as a third group frame) 55 that holds a third group lens 67, and a straight-moving float key 56.

A shutter blade 68 is assembled to the second group frame 54, and a blade retainer 58 which is a pressing member for these shutter blades 68 is attached. A compression spring 57 is inserted between the blade retainer 58 and the third group frame 55 to eliminate back and forth movement play.

The cam frame 52 has a male helicoid 52 screwed onto the female helicoid 51a of the fixed frame 51 on the outer peripheral portion of the rear end.
a is provided, and the female helicoid 52b is further provided on the inner peripheral portion.
Two sets of cam grooves 52c and 52d, and a bayonet groove 52h which is an inner peripheral groove for holding the straight float key 56 at the rear end of the inner peripheral portion.
And are provided. The female helicoid 52b
And the two sets of cam grooves 52c and 52d are shown in FIG.
As shown in a development view of the inner peripheral surface of the cam frame, the cam frames are arranged so as to intersect with each other.

The first group frame 53 is provided with a male helicoid 53a screwed to the female helicoid 52b of the cam frame 52 on the outer peripheral portion of the rear end thereof. A cam follower 62 slidably fitted in the cam groove 52d of the cam frame 52 is planted (fixedly supported) on the outer peripheral portion of the second group frame 54. 3 group frame 5
5, a cam follower 61 slidably fitted in the cam groove 52c of the cam frame 52 is planted (fixedly supported) on the outer peripheral portion. The straight-movement float key 56 includes a convex straight-movement key 56b slidably fitted in the straight-movement guide groove 51b of the fixed frame 51 and a bayonet claw 56a slidably fitted in the bayonet groove 52h of the cam frame 52. It is provided.

In the lens barrel 50 having the above-mentioned advance / retreat driving mechanism, when the cam frame 52 is rotationally driven by the lens barrel advancing / retreating drive section, the cam frame 52 moves forward and backward while rotating. The straight-moving float key 56 moves integrally with the rotating cam frame 52 in the optical axis O direction, and moves forward and backward without rotating. First group frame 53, second group frame 54, third group frame 55
Is driven forward and backward as the cam frame 52 rotates and forward and backward while the rotation is restricted by the straight forward float key 56.

The inner peripheral structure of the cam frame 52 will be described in more detail with reference to FIGS. Note that FIG.
1 is a development view of the inner peripheral surface of the cam frame, and FIG.
13 is a cross-sectional view taken along the line D-D of FIG. 13, and FIG.

As shown in FIG. 11, the inner peripheral surface of the cam frame 52 is provided with a predetermined lead female helicoid 52b, three sets of cam grooves 52c and 52d, and a bayonet groove 52h on the rear end surface side. Further, the bayonet groove 52 of the cam frame 52
In the ring-shaped rear end wall portion 52j of the rear end surface where h is provided,
As shown in FIG. 13, six notched insertion portions 52e for inserting the bayonet claws 56a and the cam followers 61,
Three notch-shaped insertion portions 52f and 52g for inserting 62 are provided. Cam follower 61,
62 is a cam groove 52 through the insertion portions 52f and 52g.
c, 52d. The bayonet claw 56a is fitted into the bayonet groove 52h through the insertion portion 52e. In this case, the inner diameter of the inner peripheral surface 52i (FIG. 13) of the cam frame 52 and the inner diameter of the rear end wall portion 52j are equal.

The female helicoid 52b of the cam frame 52 is
It has a screw thread height (valley depth) H0 from the inner peripheral surface 52i. The male helicoid 53a of the first group frame 53, which is screwed into the female helicoid 52b, also has the same dimension as the screw thread height (valley bottom depth) H0. In addition, the cam grooves 52c and 52d of the cam frame 52
Has a groove depth C0 from the inner peripheral surface 52i. The minimum thickness t0 of the peripheral portion of the cam frame 52 is set. The thickness d0 from the outer peripheral surface to the inner peripheral surface 52i where the cam groove is provided is C0 + t
It becomes 0.

The total radial thickness (occupied frame thickness) T0 of the cam frame 52 having the minimum wall thickness t0 is defined by the female helicoid 5 described above.
The screw thread height H0 of 2b and the thickness d0 from the outer peripheral surface to the inner peripheral surface 52i of the cam groove are added. That is, the total radial thickness T0 is: T0 = H0 + d0. Substituting the above-mentioned d0 = C0 + t0 results in T0 = H0 + C0 + t0 (1). Incidentally, as in the conventional lens barrel shown in FIG. 10 described above, JP-A-6-67076 discloses an advancing / retreating drive mechanism in which a helicoid and a cam groove are arranged so as to intersect with each other on the inner peripheral surface of the cam frame. There is a disclosed zoom lens barrel technology.

[0011]

In the conventional lens barrel 50 shown in FIG. 10 described above, the cam grooves 52c, 52 are formed.
Although d is arranged to intersect with the female helicoid 52b, they are arranged in independent shapes. Therefore, the total radial thickness (occupied thickness) T0 of the cam frame 52, which maintains the minimum thickness t0, is a thickness obtained by simply superposing the thread height H0 and the inner and outer peripheral surface thickness d0. Cage,
It cannot be said that the lens barrel is sufficiently thin, and the lens barrel is not downsized.

Therefore, in order to reduce the total thickness T0 of the cam frame 53 while keeping the minimum thickness t0, it is necessary to make the valley bottom of the female helicoid 52b into the thick portion of the inner peripheral surface 52i. In consideration, a clearance (cutout) for inserting the tip of the male helicoid 53a of the first group frame 53 is required in the rear end wall 52j of the bayonet groove 52h of the cam frame 52. However, when the escape portion for inserting the male helicoid 53a is provided in the rear end wall portion 52j in this manner, the catching of the bayonet claw 56a of the straight-moving float key 56 is reduced, and the straight-moving float key 56 falls off. The problem of occurs.

The present invention has been made to solve the above-mentioned problems, and provides a lens barrel in which the lens barrel can be made smaller and more compact, and the frame member can be reliably driven back and forth. The purpose is to do.

[0014]

According to a first aspect of the present invention, there is provided a lens barrel having a female helicoid formed on an inner peripheral surface thereof.
And the first frame so that they cannot move in the optical axis direction,
A linear guide member rotatably supported around the optical axis, an engaging claw provided on the linear guide member, and a first frame, the engaging claw being provided around the optical axis. A guide portion for rotatably guiding relative to the frame, a claw insertion portion provided at one end of the first frame for inserting the engaging claw into the guide portion, and the first portion. A second frame having a male helicoid that can be screwed with the female helicoid and is provided at one end of the first frame to screw the male helicoid with the female helicoid. The helicoid insertion part is provided, and the claw insertion part is provided in the helicoid insertion part.

In the lens barrel according to claim 2 of the present invention, the first female helicoid is formed in the first region of the inner peripheral surface,
A first frame in which a second female helicoid having the same lead as the first female helicoid and a shallow groove depth is formed in the region of
A linear guide member that is supported immovably in the optical axis direction with respect to the first frame and rotatably around the optical axis; a first engagement claw provided on the linear guide member; Two engaging claws, and the first engaging claw and the second engaging claw provided on the first frame are guided to be rotatable relative to the first frame around the optical axis. A guide part, a first claw insertion part provided at one end of the first frame for inserting the first engaging claw into the guide part, and provided at one end of the first frame. A second pawl insertion portion for inserting the second engaging pawl into the guide portion and an inner portion of the first frame are arranged, and the first female helicoid and the second female helicoid are screwed into each other. A second frame having a first male helicoid and a second male helicoid, and provided at one end of the first frame,
And a helicoid insertion portion for screwing the first male helicoid with the first female helicoid, the first claw insertion portion being formed in the helicoid insertion portion.

A lens barrel according to a third aspect of the present invention is the lens barrel according to the second aspect, wherein the second engaging claw is circumferentially arranged with respect to the first engaging claw. When the first engaging claw and the second engaging claw are arranged at positions separated by a predetermined amount and one of the first engaging claw and the second engaging claw is in a position corresponding to the helicoid insertion part in the circumferential direction, the other is the helicoid insertion part. It is located outside.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a lens barrel which is an embodiment of the present invention, and FIG. 2 is a vertical sectional view of the lens barrel.

FIG. 3 is an exploded perspective view of the cam frame, the first group frame and the rectilinear float key incorporated in the lens barrel as seen from the image side.

In the following description, the subject side of the lens barrel is the front and the image side is the rear. Further, the optical axis of the lens composed of the first lens group, the second lens group, and the third lens group is the optical axis O. Further, the rotation direction around the optical axis O is indicated by the rotation direction when viewed from the subject side.

The lens barrel 20 of one embodiment of the present invention is
As shown in FIGS. 1 and 2, a fixed frame 1 that is fixedly supported by a camera body, a cam frame 2 that is a first frame that fits into the fixed frame 1, and rotates and moves back and forth, and the inside of the cam frame 2. A first group frame (hereinafter, referred to as a first group frame) 3 which is a second frame which is fitted in the first group frame 3 and which moves straight in the optical axis O direction, and a third group which is fitted in the first group frame 3 and moves straight in and out. A second group frame (hereinafter referred to as a second group frame) 4 and a third group frame (hereinafter referred to as a third group frame) 5 that are frames.
And a straight-moving float key 6 which is a straight-moving guide member that moves straight forward and backward along the optical axis O direction.

Further, the lens barrel 20 includes a compression spring 10 arranged between the second group frame 4 and the third group frame 5, and
A blade presser 8 supported by the group frame 4 and a shutter blade 18
A focus frame 9 movably supported by the second group frame 4, a flare stop 13 held by the straight float key 6, and a rotational driving force from a lens barrel driving unit (not shown) are transmitted to the cam frame 2. The long cam frame drive gear 7 and the first, second, and third lens groups 1 which are a plurality of photographing lenses held by the first lens group frame 3, the focus frame 9, and the third lens group frame 5, respectively.
5,16,17.

The fixed frame 1 is an annular member, and a female helicoid (helicoid screw) 1a and an optical axis O are provided on the inner peripheral portion thereof.
There are provided three rectilinear grooves 1c extending in the direction and a concave gear chamber 1b extending in the optical axis O direction. A long cam frame drive gear 7 is rotatably attached to the gear chamber 1b.

The cam frame 2 is an annular member, and a male helicoid (helicoid screw) 2 into which a female helicoid 1a of the fixed frame 1 is screwed is fitted to a ring-shaped outer peripheral portion 2a having a predetermined width behind the cam frame 2.
b and a gear portion 2c that meshes with the cam frame drive gear 7 are provided in an overlapping manner. Three sets of first female helicoids (helicoid screws) 2d having deep roots (standard tooth profile) and three pairs of second female helicoids each having a relatively shallow root (having the same leads on the inner peripheral surface 2p of the cam frame 2). Helicoid screw) 2
e and three second group cam grooves 2f and three group cam grooves 2g arranged in a state of intersecting the second female helicoid 2e (FIG. 4).

Further, a helicoidal thread bayonet is formed on a ring-shaped rear end wall 2q which is one end along the inner peripheral surface having the same diameter as the inner peripheral surface 2p on the rear end surface of the cam frame 2. Helicoid insertion portion 2h and bayonet claw insertion portion 2 that is the first nail insertion portion are provided as notch-shaped insertion portions for inserting the nails and the cam followers into the cam frame 2.
i, 2i ', a bayonet claw insertion part 2j, 2j' which is a second claw insertion part, a second and third group cam follower insertion part 2k,
2m is placed. In addition, a bayonet groove 2n, which is a guide portion, is provided along the inner circumference of the rear end wall portion 2q.
The bayonet groove 2n is a groove into which the bayonet claws 6g, 6g ', 6h, 6h' of the straight-moving float key 6 are fitted and rotate and slide.

When the cam frame 2 is fitted in the inner peripheral portion of the fixed frame 1 and is rotationally driven by the cam frame drive gear 7 via the gear portion 2c, the female helicoid 1a and the male helicoid 2b rotate and the light is emitted. Moves back and forth in the direction of axis O.

The first and second female helicoids 2d, 2
e, the second and third group cam grooves 2f and 2g, and the insertion portions 2h and 2
Each shape and arrangement position of i, 2j, 2i ', 2j', 2k, 2m and bayonet groove 2n will be described in detail later.

The first group frame 3 is a cylindrical member and has a first male helicoid 3b (3 places) and a second male helicoid 3c (3) on a ring-shaped outer peripheral portion 3a having a predetermined width behind the first group frame 3.
Location) is provided. In addition, in the inner peripheral portion of the first group frame 3,
Three straight grooves 3d are provided along the optical axis O direction. The first male helicoid 3b is a helicoid screw having a high mountain portion that is screwed into the first female helicoid 2d of the cam frame 2, and the second male helicoid 3c is screwed into the second female helicoid 2e of the cam frame 2. It is a helicoid screw with a low peak. The first and second female helicoids 2d and 2e both transmit the rotational driving force, but especially the first female helicoid 2d has a function of preventing the screwed state from being disengaged when an external force such as an impact is applied. Doubles as the second female helicoid 2e
Particularly has a function of preventing light leakage from the fitting gap.

The first-group frame 3 is supported on the outer peripheral portion of the straight-moving float key 6 by a straight-moving guide protrusion 6a fitted in the straight-moving groove 3d so as to be movable back and forth in the optical axis O direction.
It is driven back and forth by the first and second female helicoids 2e and 2d.

The second group frame 4 is a cylindrical member and has three extending portions 4a extending in the direction of the optical axis O on its outer peripheral portion. A guide protrusion 4b is provided on each of the three extending portions 4a, and a cam follower 11 is implanted on each of the three guide protrusions 4b. The cam follower 11 is slidably fitted in the second group cam groove 2f of the cam frame 2, and the guide protrusion 4b is slidably fitted in a straight guide groove 6b of a straight float key 6 described later.

The second group frame 4 is supported at the inner peripheral portion of the straight-moving float key 6 so as to be movable back and forth in the direction of the optical axis O by the straight-moving guide groove 6b, and is connected to the cam frame 2 through the cam follower 11.
It is driven back and forth by the group cam groove 2f.

The third group frame 5 is a disk-shaped member, and has three convex portions 5a on its outer peripheral portion. A guide protrusion 5b is provided on each of the three protrusions 5a, and a cam follower 12 is implanted on each of the three guide protrusions 5b. The cam follower 12 is slidably fitted in the third group cam groove 2g of the cam frame 2, and the guide protrusion 5b is slidably fitted in a straight guide groove 6c of a straight float key 6 described later.

The third group frame 5 is supported at the inner peripheral portion of the straight-moving float key 6 so as to be movable back and forth in the direction of the optical axis O by the straight-moving guide groove 6c, and the cam frame 2 is connected to the third frame 3 through the cam follower 12.
It is driven back and forth by the group cam groove 2g.

The straight-moving float key 6 is an annular member, and three protruding straight-moving key portions 6f projecting in the radial direction are provided on the outer peripheral portion of the rear end flange portion 6d of the annular member. Further, the first engaging portion 3 having a height lower than the outer diameter of the rear end ring portion 6d is provided on the outer peripheral portion 6i having a predetermined step and separated from the rear end flange portion 6d by a predetermined distance. 6g bayonet claws 6g, 6
g ′ and the three protruding bayonet claws 6 of the second engaging portion
h, 6h 'are provided.

Further, the straight-moving float key 6 includes three straight-moving guide protrusions 6a along the optical axis O direction on the front annular portion of the outer peripheral portion 6i and three straight-moving guides opening from the inner peripheral side to the outer peripheral side. A groove 6b and three straight guide grooves 6c are provided.

The straight advance key portion 6f is slidably fitted in the straight advance groove 1c of the fixed frame 1. Bayonet claw 6 above
The g and 6g 'and the bayonet claws 6h and 6h' are slidably fitted into the bayonet groove 2n of the cam frame 2 and are bayonet-coupled. Therefore, the straight-moving float key 6 rotates relative to the cam frame 2 and is integrally driven in the optical axis O direction.

The compression spring 10 is arranged between the second group frame 4 and the third group frame 5 and always biases the second and third group frames 4 and 5 in the direction of separating them from each other. 2, 3 group frame 4, 5
Receives the above-mentioned urging force, and moves forward and backward with the fitting backlash between each cam follower and cam groove removed.

Next, the first and second female helicoids formed on the inner peripheral surface of the cam frame 2, the second and third group cam grooves, the bayonet groove, and the insertion portions for the male helicoid, the bayonet claw, and the cam follower. 2h, 2i, 2i ', 2j, 2j', 2
The shape and arrangement of k, 2m, etc. will be described in detail with reference to FIGS. FIG. 4 is a development view of the inner peripheral surface of the cam frame. 5 is a sectional view taken along the line AA of FIG. 4, FIG. 6 is a view taken along the line BB of FIG. 4, and FIG. 7 is a view taken along the line CC of FIG. 8 and 9 are views of the rear end wall portion of the cam frame seen from the rear (image side), and also showing the relative positions of the bayonet claws of the straight-moving float key. And FIG.
The relative position of the bayonet claws is different between the state of FIG.

On the inner peripheral surface 2p having a predetermined inner diameter of the cam frame 2, as shown in FIG. 4, first regions R1 and second regions R2 which are divided along the leads of the helicoid are alternately arranged. 3 areas are provided for each. First region R1
Is a region having a smaller width in the circumferential direction than the second region R2,
It is arranged at a predetermined interval. In the present embodiment, the first region R1 and the second region R2 are arranged at regular intervals in order to arrange them in a well-balanced manner in the circumferential direction.

The first female helicoid 2d is arranged in the first region R1. In the second region R2, the second female helicoid 2e and the second group cam groove 2f and the third group cam groove 2g are arranged in an intersecting state. However, the first and second female helicoids 2d and 2e have the same lead.

FIG. 5 shows the shape of the first and second female helicoids 2d, 2e and the second and third group cam grooves 2f, 2g in the cross section orthogonal to the helicoid lead (cross section AA in FIG. 4). The second and third group cam grooves 2f and 2g are cam grooves having a groove depth C0 provided on the inner peripheral surface 2p.

The first female helicoid 2d has a valley bottom 2t.
Are formed along the inner peripheral surface 2p on the peripheral surface having the same diameter as the bottom surface of the cam grooves 2f and 2g having the depth C0. The thread height H0 from the root bottom 2t of the first female helicoid 2d to the thread apex 2r is the height of the standard tooth profile of the applied helicoid.

The second female helicoid 2e has an inner peripheral surface 2p.
It is provided above, and the position of the valley bottom is made to coincide with the inner peripheral surface 2p. The thread crest 2s of the second female helicoid 2e and the thread crest 2r of the first female helicoid 2d are on the peripheral surface having the same diameter. Therefore, the thread height from the valley bottom of the second female helicoid 2e (corresponding to the inner peripheral surface 2p) to the thread apex 2s is only the cam groove depth C0 smaller than the thread height H0 of the first female helicoid 2d. It is low and is given by the dimension (H0-C0).

The minimum wall thickness t0 of the cam frame 2 in the radial direction.
Is the dimension from the bottom surface of the cam grooves of the cam grooves 2f and 2g, or the valley bottom portion 2t of the first female helicoid 2d to the outer peripheral surface. Further, the total radial thickness of the cam frame 2 (occupied frame thickness)
T1 is given by a dimension (H0 + t0) obtained by adding the thread height H0 of the first female helicoid 2d and the minimum wall thickness t0. That is, T1 = H0 + t0 (2).

As shown in FIG. 5, the tooth profiles of the first and second male helicoids 3b and 3c of the first-group frame 3 screwed into the first and second female helicoids 2d and 2e of the cam frame 2 are also the same as those described above. The shape corresponds to the tooth profile of the first and second female helicoids 2d and 2e.

On the rear end side of the inner peripheral surface 2p of the cam frame 2,
As shown in FIG. 4, a bayonet groove 2n having a predetermined width and a rear end wall portion 2q in which the respective insertion portions are arranged are provided along the inner peripheral direction. The diameter of the inner peripheral surface of the rear end wall portion 2q is the same as the inner peripheral surface 2
It matches the diameter of p.

The depth of the bayonet groove 2n is equal to the inner peripheral surface 2
It is a groove slightly deeper than the cam grooves 2f, 2g and the valley bottom of the first female helicoid 2d, and has a depth such that the bayonet claws 6g, 6h, 6g ', 6h' of the straight-moving float key 6 can be fitted into p.

As shown in FIGS. 3 and 4 and the like, cam follower insertion portions 2k and 2m, helicoid insertion portion 2h, and bayonet claw insertion portions 2i and 2i are formed in the rear end wall portion 2q as notched insertion portions. ', 2j, 2j' are arranged.

The cam follower insertion portions 2k and 2m are
This is a cam follower insertion portion into which three sets of cam followers 11, 12 of the second and third group frames 4 and 5 arranged at the insertion opening side (rear end side) opposing positions of the second and third group cam grooves 2f and 2g can be inserted.

The helicoid insertion portions 2h are three insertion portions into which the first male helicoid 3b of the first group frame 3 can be inserted.
The first female helicoids 2d of the first region R1 are arranged at three equal positions extending to the rear end side, and each is a notch of the occupied width of the first female helicoid 2d (width of the first region R1).

The bayonet claw insertion portions 2i, 2i ', 2
Of j and 2j ', the claw insertion portions 2i and 2j are four pairs of insertion portions (insertion ports) into which the four bayonet claws 6g and 6h can be inserted by two pairs of the straight-moving float key 6. Further, the claw insertion portions 2i ′, 2j ′ are a pair of two insertion portions (insertion ports) into which the two bayonet claws 6g ′, 6h ′ of the straight advance float key 6 can be inserted. Then, the two bayonet claw insertion portions 2i and the one bayonet claw insertion portion 2i 'are arranged in a state of being overlapped with each other in the helicoid insertion portions 2h arranged at equal intervals at the three equally divided positions.

As will be described later, the bayonet claw insertion portions 2i and 2i 'are displaced relative to the helicoid insertion portion 2h. In addition, the bayonet claw insertion portion 2i,
The depths of 2j, 2i ', 2j' are slightly deeper than the helicoid insertion portion 2h, corresponding to the shapes of the bayonet claws 6g, 6h, 6g ', 6h' of the straight advance float key 6. Therefore, when the straight-moving float key 6 rotates relatively to the cam frame 2, the bayonet claw 6h or 6g ', 6h' in the helicoid insertion portion 2h is a portion where the helicoid insertion portion 2h is less likely to be caught. It is likely to come off from the bayonet groove 2n, and may come off when it coincides with the bayonet claw insertion portions 2i, 2i '.

Therefore, the relative rotation of the straight-moving float key 6 causes the two pairs of bayonet claws 6g and 6h to move into the bayonet groove 2n.
6g of bayonet claws to prevent it from falling off
Arrangement angle θ4 of bayonet claws 6g and 6h so that 6h is not located in the helicoid insertion part 2h at the same time.
To decide. That is, the arrangement angle θ4 of the bayonet claws 6g and 6h is equal to the angle θ1 of the helicoid insertion groove 2h.
(FIG. 8).

Claw width angle θ of the bayonet claws 6g, 6h
2 and θ3, the arrangement interval angle θ4 of the bayonet claw insertion portions 2i, 2j is determined so as to satisfy θ4 ≧ θ1 + (θ2 / 2) + (θ3 / 2) (3). When θ3 = θ2, the above equation (3) is θ4 ≧ θ1 + θ2, but if the arrangement interval angle θ4 is the narrowest angle, then θ4 = θ1 + θ2 (4). The arrangement interval angle θ4 of the bayonet claw insertion portions 2i, 2j is determined so as to satisfy the above (4).

On the other hand, another pair of bayonet claw insertion portions 2
The arrangement angle θ4 of i ', 2j' is also equal to the bayonet claws 6g ', 6'.
In order to prevent h ′ from falling out of the bayonet groove 2n, the same equation (4) as described above in relation to the angle θ1 of the helicoid insertion portion 2h
Is determined to satisfy.

As described above, the two bayonet claw insertion portions 2i and the one bayonet claw insertion portion 2i 'are arranged in three equal positions at equal intervals, and the helicoid insertion portions 2h are arranged at equal intervals.
They are arranged in a state where they are superposed at positions where their relative positions are displaced from each other. For this reason, the fitting phase relationship at the time of assembling the cam frame 2 with the straight-moving float key 6 is specified as shown in FIGS. By specifying the fitting phase, the cam frame 2 is set to 1
The fitting phase in the rotation direction of the group frames 3, 2 and 3, and 5 does not change depending on the product, and the optical performance of the lens barrel can be stabilized. Further, since it is possible to assemble only in a specific fitting phase, there is no possibility of miscombining. Next, an example of an assembling procedure in the lens barrel 20 of the present embodiment having the above-mentioned configuration will be described. The cam frame 2
Is helicoidally coupled to the fixed frame 2, and the cam frame drive gear 7
It is assumed to be incorporated in the state of meshing with. Therefore, the first male helicoid 3b of the first group frame 3 is inserted from the helicoid insertion portion 2h of the cam frame 2 to bring the cam frame 2 and the first group frame 3 into a helicoid screwing state.

Next, the linear guide grooves 6b and 6c of the linear float key 6 are inserted into the guide protrusions 4b of the second group frame 4 and the third group frame 5, respectively.
5b is slidably inserted into the straight float key 6 for a few
The group frames 4 and 5 are assembled.

Then, the first group frame 3 fitted in the cam frame 2
While inserting the straight-movement guide protrusion 6a of the straight-movement float key 6 into the straight-movement groove 3d, the straight-movement float key 6 is fitted into the inner peripheral portion of the first-group frame 3, and the cam followers 11 of the second-, third-group frames 4 and 5 are inserted. , 12 are inserted from the cam follower insertion portions 2k, 2m of the cam frame 2, and the second and third group cam grooves 2 of the cam frame 2 are inserted.
Engage with f and 2g. Thereafter, the bayonet claws 6g, 6h, 6g ', 6h' of the straight advance float key 6 are inserted from the bayonet claw insertion portions 2i, 2j, 2i ', 2j' of the cam frame 2 and engaged with the bayonet groove 2. Further, the straight-movement key 6f of the straight-movement float key 6 is fitted into the straight-movement groove 1c of the fixed frame 1, and the assembling of the lens barrel 20 is completed.

Explaining the forward / backward movement of the lens barrel 20 of the present embodiment described above, the cam frame 2 is driven by the cam frame 2 in the collapsed state in which all the frame members such as the cam frame 2 are retracted to the collapsed position. When the cam frame 2 is driven to rotate by the gear 7, the cam frame 2 is extended from the retracted position to the wide position where the image can be taken, and further to the tele position while rotating. Cam frame 2
At the same time, the straight-ahead float key 6 goes straight ahead and is fed out.
The first-group frame 3 is a wide position where the first and second male helicoids 3b and 3c, which are screwed with the cam frame 2 in a state where rotation is restricted by the rectilinear float key 6, can be photographed from the retracted position, It is extended to the position. Furthermore, a few
With the rotation of the group frames 4 and 5 restricted by the straight-moving float key 6, the cam followers 11 and 12 are moved from the collapsing positions P11C and P12C to the wide corresponding positions P11W and P12W by the second and third group cam grooves 2f and 2g, respectively. Driven to the telephoto corresponding positions P11T and P12T (FIG. 4), the second and third group frames 4 and 5 are extended from the retracted position to a wide position where they can be photographed, and further to the telephoto position.

According to the lens barrel 20 of this embodiment having the above-described configuration, the valley depth of the second female helicoid 2e provided on the cam frame 2 is reduced, and the second female helicoid 2e and the cam grooves 2f, 2g are formed. Are arranged in the second region so as to intersect with each other. With this arrangement, the total thickness T1 of the cam frame 2 in the state where the radial minimum thickness t0 of the cam frame 2 is secured is (height H0 of the first female helicoid 2d) + (minimum thickness t0
), The total thickness T1 of the cam frame 2 which is the radial occupied frame thickness can be reduced, and the lens barrel 20 can be downsized. In the conventional lens barrel 50 described above, the total thickness T0 of the cam frame 52 is given by (height H0 of the female helicoid 52b) + (cam groove depth C0) + (minimum thickness t0). The total thickness T1 of the cam frame 2 in this embodiment is thinner than the total thickness T0 of the cam frame 52 of the conventional lens barrel by the cam groove depth C0.

Moreover, light leakage from the fitting gap of the inner peripheral surface 2p in the second region of the cam frame 2 is caused by the second female helicoid 2e.
Can be prevented with. Further, even when an external force is applied, there is little risk of screwing off due to the first female helicoid 2d having a high mountain height (deep valley).

Further, the above two bayonet claws 6g and 6
By arranging h or 6g 'and 6h' open by the above-mentioned predetermined angle .theta.4 respectively, bayonet claws 6g and 6 provided as a pair of the straight advance float key 6 are provided.
h or 6g 'and 6h', when one bayonet claw 6h or 6h 'is inside the bayonet claw insertion portion 2i or 2i' of the cam frame 2, the other bayonet claw 6g or 6g 'is located in the bayonet groove 2n outside the helicoid insertion portion 2h. Therefore, the bayonet claws 6g and 6g 'are reliably prevented from coming off the bayonet groove 2n.

According to the present invention described above, (1) the first female helicoid is formed in the first region of the inner peripheral surface, the same lead as that of the first female helicoid is formed in the second region, and the groove depth is A first frame on which a shallow second female helicoid is formed; a straight guide member that is supported so as to be rotatable about the optical axis but immovable in the optical axis direction with respect to the first frame; The first engaging claw and the second engaging claw provided on the guide member, and the first engaging claw and the second engaging claw provided on the first frame around the optical axis. A guide part for rotatably guiding with respect to the first frame, and a first part for inserting the first engaging claw provided at one end part of the first frame into the guide part. And a second claw insertion portion for inserting the second engaging claw provided at one end of the first frame into the guide portion. And, the first
A second frame having a first male helicoid and a second male helicoid with which the first female helicoid and the second female helicoid are screwed, the second frame being disposed inside the frame of the first female helicoid and the second female helicoid, respectively. A helicoid insertion part for screwing the first male helicoid with the first female helicoid, wherein the first claw insertion part is formed in the helicoid insertion part, It is possible to propose a lens barrel characterized in that three engaging claws and second engaging claws and three first claw inserting portions and second claw inserting portions are provided in the circumferential direction.

(2) The first pawl insertion portion, the second pawl insertion portion, and the helicoid insertion portion are groove portions provided at one end of the first frame.
The lens barrel described can be proposed.

(3) The lens barrel according to (2), wherein the groove depths of the first and second claw insertion portions are deeper than the groove depth of the helicoid insertion portion. Can be suggested.

(4) The groove width in the circumferential direction of the first pawl insertion portion and the second pawl insertion portion is narrower than the groove width in the circumferential direction of the helicoid insertion portion. The lens barrel described in 2) or (3) can be proposed.

[0066]

As described above, according to the present invention,
As a configuration in which the second frame and the rectilinear guide member are fitted in the first frame, a helicoid insertion portion for inserting the male helicoid of the second frame is provided in the first frame, and a pair of rectilinear guide frames When the engaging claws are provided and one of the pair of engaging claws is located in the helicoid insertion portion where the claws are easily disengaged, the other engaging claw is
(EN) A lens barrel that can be surely prevented from coming off of a straight guide member by adopting a configuration that is positioned other than the helicoid insertion portion, and that further downsizing and downsizing of the lens barrel can be realized. be able to.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a lens barrel according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the lens barrel of FIG.

3 is an exploded perspective view of a cam frame, a first group frame, and a rectilinear float key of the lens barrel of FIG.

4 is a development view of an inner peripheral surface of a cam frame of the lens barrel of FIG.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a view taken along the line BB of FIG.

FIG. 7 is a view on arrow CC of FIG.

8 is a view of the cam frame of the lens barrel of FIG. 1 viewed from the image side, showing a state immediately after inserting a straight-ahead float key.

9 is a view of the cam frame of the lens barrel of FIG. 1 as viewed from the image side, showing a state in which the rectilinear float key is further rotated relative to the state shown in FIG.

FIG. 10 is a vertical cross-sectional view of a conventional lens barrel.

11 is a development view of the inner peripheral surface of the cam frame of the conventional lens barrel of FIG.

12 is a cross-sectional view taken along the line DD of FIG.

13 is a view of the cam frame of the conventional lens barrel of FIG. 10 as viewed from the image side.

[Explanation of symbols]

2 ... Cam frame (first frame) 2d ... 1st female helicoid (female helicoid) 2e ... Second female helicoid (female helicoid) 2h ... Helicoid insertion part 2i, 2i '... Bayonet claw insertion part (first claw insertion part) 2j, 2j '... Bayonet claw insertion part (second claw insertion part) 2n ... Bayonet groove (guide part) 2q ... rear end wall portion (one end portion of the first frame) 3 ... 1 group frame (second frame) 6 ... Straight advance float key (straight guide member) 6g, 6g '... Bayonet claw (engaging claw, first engaging claw) 6h, 6h '... Bayonet claw (engaging claw, second engaging claw) R1 ... First area R2 ... Second area

Claims (3)

[Claims] 1. A first helicoid having an inner peripheral surface formed with a female helicoid
A linear guide member that is supported immovably in the optical axis direction with respect to the first frame and rotatable about the optical axis; an engaging claw provided on the linear guide member; A guide portion that is provided on the first frame and that guides the engaging claw so as to be rotatable relative to the first frame around the optical axis; and a guide portion that is provided at one end of the first frame. A claw inserting portion for inserting an engaging claw into the guide portion, a second frame arranged inside the first frame and having a male helicoid screwable with the female helicoid, and the first frame. And a helicoid insertion portion provided at one end of the frame for screwing the male helicoid with the female helicoid, wherein the claw insertion portion is provided in the helicoid insertion portion. Cylinder. 2. A first female helicoid is formed in a first region of the inner peripheral surface, and a second female helicoid having the same lead as that of the first female helicoid and a shallow groove depth is formed in a second region. A first frame, a linear guide member that is supported immovably in the optical axis direction with respect to the first frame and rotatably around the optical axis, and a first frame provided on the linear guide member. The engaging claws, the second engaging claws, and the first engaging claws and the second engaging claws provided on the first frame relative to the first frame about the optical axis. A guide portion that rotatably guides, a first pawl insertion portion that is provided at one end of the first frame and that inserts the first engaging pawl into the guide portion, and the first pawl insertion portion. A second pawl insertion portion provided at one end of the frame for inserting the second engaging pawl into the guide portion, and arranged inside the first frame. A second frame having a first male helicoid and a second male helicoid with which the first female helicoid and the second female helicoid are screwed, and the first frame, and the second frame having the first male helicoid and the second male helicoid. A helicoid insertion part for screwing a male helicoid with the first female helicoid, wherein the first claw insertion part is formed in the helicoid insertion part. 3. The second engaging claw is arranged at a position separated from the first engaging claw by a predetermined amount in the circumferential direction, and the first engaging claw and the second engaging claw are arranged. The lens barrel according to claim 2, wherein when one of the claws is in a position corresponding to the helicoid insertion part in the circumferential direction, the other is at a position outside the helicoid insertion part.