JP2007114531A - Cam mechanism of lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve lightweight and miniaturization of the whole device by preventing a cam follower from slipping off from a cam groove by a separation restriction means in each cam groove opening part and enlarging a length in a rotating shaft direction of the cam groove without enlarging the length in the rotating shaft direction of a rotation member. <P>SOLUTION: An inner cam groove group 74 forms a front inner peripheral cam groove 75 and a rear inner peripheral cam groove 76 having the same cam curves by differing the position of at least an optical axis direction. At least one cam groove 75 out of a plurality of inner peripheral cam grooves is provided with first and second cam groove opening parts 78 by being opened to both the end faces of the optical axis direction of a cam ring 15. The remaining cam grooves 76 are provided with third cam groove opening parts 78 by being opened to one end face or the other end face of the optical axis direction of the cam ring. A cam pin 84 comprises a plurality of cam pins 85 and 86 engaged slidably with the plurality of cam grooves, and at least one of the plurality of the cam pins is maintained to be engaged with any one of the plurality of the cam grooves. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cam mechanism for a lens barrel in which a plurality of cylinders housed in a telescopic manner are expanded and contracted by a cam mechanism.

  As a conventional cam mechanism of this type of lens barrel, for example, there is one described in Patent Document 1. Patent Document 1 describes a feeding cam mechanism using a cam ring and a rectilinear ring, and in particular, a lens moving mechanism using a cam ring of a zoom lens barrel. The zoom lens barrel feeding cam mechanism according to Patent Document 1 has the following features: “It has a cam ring that is rotatable and has a cam groove on its peripheral surface, and a cam follower that engages with the cam groove, and is guided straight in the optical axis direction. A zoom lens barrel feeding cam mechanism that includes a rectilinear ring that supports at least a part of the photographic optical system and moves the rectilinear ring back and forth in the optical axis direction of the photographic optical system according to rotation of the cam ring. In addition, a plurality of cam grooves having the same basic locus are formed at different positions at least in the optical axis direction, and none of the plurality of cam grooves is at least one of the front part and the rear part. The cam groove is opened to the end face of the cam ring as a short length, and a plurality of cam followers that respectively engage with the plurality of cam grooves are formed at different positions in the optical axis direction in the straight advance ring. In at least one dynamic end and the rear moving end, the cam follower from a portion of the plurality of the cam groove out, another cam follower and the cam groove is characterized by maintaining the engagement. "

According to the zoom lens barrel feeding cam mechanism described in Patent Document 1 having such a configuration, “the size of the cam ring is reduced while the necessary amount of movement of the lens group and other linearly moving members is ensured. Is possible ”(paragraph [0063] of the specification).
JP 2004-85932 A

  Generally, in this type of lens barrel cam mechanism, the maximum amount of movement of the rectilinear movement frame is determined by the length of the cam groove provided in the cam ring in the direction of the rotation axis. A gear portion is provided on one side of the cam ring in the rotation axis direction, but the gear portion needs to be formed so as not to interfere with the cam groove. Further, the length of the cam groove in the rotation axis direction is also limited by the length of the gear portion in the rotation direction. Therefore, the length of the cam ring in the direction of the rotation axis needs to be at least a length obtained by adding the width of the gear portion to the length of the cam groove in the direction of the rotation axis.

  However, in lens barrels used in recent digital still cameras and the like, especially in lens barrels having a zoom function, there is a strong demand for higher magnification of the optical system, and the lens frames and the like go straight. There is a need to increase the amount of movement of the moving frame in the optical axis direction. On the other hand, there is an increasing demand for downsizing of the lens barrel itself, and as a result, the amount of movement of the rectilinear moving frame in the optical axis direction can be increased without increasing the length of the cam ring in the rotation axis direction. A mechanism is needed.

  However, in the conventional example having the configuration as described above, it is insufficient that the amount of movement of the rectilinear movement frame in the rotation axis direction cannot be made larger than the length of the rectilinear movement frame in the rotation axis direction. There was a point. This insufficiency will be described with reference to FIGS. 36A, B, C and FIG. 36A to 36C schematically show the configuration of the zoom lens barrel described in Patent Document 1, and FIG. 37 shows the cam development view of FIG. 20 of Patent Document 1. It is.

  FIG. 36A shows a state in which the cam engagement between the second group ring and the cam ring is realized by only the rear cam pin of the second group ring, and the front cam pin is detached from the cam groove. FIG. 36B shows a state in which the front cam pin and the rear cam pin of the second group ring are both engaged with the cam groove, and the cam engagement of the second group ring and the cam ring is realized by both cam pins. FIG. 36C shows a state in which the cam engagement between the second group ring and the cam ring is realized only by the front cam pin of the second group ring, and the rear cam pin is detached from the cam groove. As described above, when a part of the cam pin is detached from the cam groove, the stroke of the second group ring in the optical axis direction is increased without increasing the length of the cam ring in the optical axis direction.

  However, in the case of the lens barrel cam mechanism described in Patent Document 1, either the front end portion (D portion in FIG. 36A) or the rear end portion (E portion in FIG. 36C) of the plurality of cam grooves is provided. Since it remains, the length of the cam groove in the optical axis direction cannot be made sufficiently large. Therefore, the amount of movement of the second group ring in the optical axis direction is not sufficient.

  The problem to be solved is that in the conventional lens barrel cam mechanism, the length of the cam ring in the rotation axis direction is not sufficiently large, and therefore it is difficult to sufficiently reduce the size of the lens barrel. It is difficult to desire high zooming of the optical system.

  The lens barrel cam mechanism of the present invention includes a rectilinear member that holds an optical element and is movable in the optical axis direction of the optical element and is provided with a cam follower, and a relative to the rectilinear member. A rotating member provided on the peripheral surface with a cam groove that is rotatable and relatively movable in the optical axis direction and that is slidably engaged with the cam follower. In the cam mechanism of the lens barrel in which the cam follower is guided by the cam groove by rotating the member and the rectilinear member is moved forward and backward in the optical axis direction, the cam groove has a plurality of cam curves having the same cam curve. The cam grooves are formed with different positions in at least the optical axis direction, and at least one cam groove of the plurality of cam grooves is opened to both end surfaces in the optical axis direction of the rotating member to be the first cam groove. An opening and a second cam groove opening are provided, and the remaining one of the plurality of cam grooves is The cam groove is opened on one end surface or the other end surface in the optical axis direction of the rotating member to provide a third cam groove opening, and the cam follower is slidably engaged with each of the plurality of cam grooves. A plurality of cam followers, and at least one of the plurality of cam followers is kept engaged with any one of the plurality of cam grooves, or the cam follower is restricted from being detached from the cam grooves. The main feature is to provide a means for restricting withdrawal.

  According to the lens barrel cam mechanism of the present invention, the first and second cam groove openings are formed by opening both ends of at least one of the plurality of cam grooves to both end surfaces in the optical axis direction of the rotating member. The longest cam groove over the entire length in the optical axis direction of the rotating member can be formed by providing the portion and positioning the cam follower in the cam groove opening. Then, the cam follower is maintained at each cam groove opening by the detachment restricting means to prevent the cam groove from falling off, thereby rotating the cam groove without increasing the length of the rotating member in the rotation axis direction. By increasing the length in the axial direction, the entire apparatus can be reduced in size and weight.

  A lens barrel that can increase the length of the cam groove in the direction of the rotation axis without increasing the length of the rotation member such as a cam ring in the direction of the rotation axis, thereby contributing to downsizing and weight reduction of the entire apparatus. The cam mechanism was realized with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 35 illustrate examples of embodiments of the present invention. 1A and 1B are perspective views of a lens barrel storage state and a lens barrel feeding state showing a first embodiment of the lens barrel cam mechanism of the present invention, and FIG. 2 is an exploded view of the lens barrel of FIG. FIG. 3 is a sectional view of the lens barrel stored, FIG. 4 is a sectional view of the lens barrel extended state, FIG. 5 is a perspective view of the stationary ring, FIG. 6 is an exploded view of the stationary ring, and FIGS. FIGS. 8A and B are a plan view and a bottom view of the cam ring, and FIGS. 9A and 9B are developed views of the outer peripheral surface and the inner peripheral surface of the cam ring. 10 is a development view of the rotation restricting member, and FIG. 11 is a development view of the rectilinear ring.

  12 is a perspective view of the automatic exposure apparatus, the interval regulating member, and the second group ring, FIG. 13 is a development view of the second group ring, FIG. 14 is a perspective view of the first group lens and the first group ring, and FIG. 16A and B are a perspective view and an enlarged view of the main part of the cam ring and the first group ring, FIGS. 17A and 17B are a front view and a bottom view, and FIGS. 18A and 18B are a right side view and a right side view. It is a YY line sectional view. 19 to 28 illustrate the positional relationship between the cam follower of the first group ring and the cam groove of the cam ring. FIGS. 19A and 19B are perspective views and cross-sectional views, and FIGS. FIGS. 21A, B, and C are perspective views, cross-sectional views, and main part explanatory views, FIGS. 22A, B, and C are also perspective views, cross-sectional views, and main part explanatory views, and FIGS. 23A, B are perspective views and cross-sectional views. 24, FIG. 25 is a perspective view, FIGS. 26A and 26B are cross-sectional views and main part explanatory views, FIGS. 27A and B are perspective views and main part explanatory views, and FIG. FIG.

  FIGS. 29A and 29B and FIGS. 30A and 30B are development views for explaining the positional relationship between the inner circumferential cam groove of the cam ring and the second group ring, and FIGS. Cross-sectional views to be described, FIGS. 32 to 34 show a first embodiment of a digital still camera using the lens barrel of FIG. 1 and the like. FIG. 32 is a front perspective view of the lens barrel storage state, FIG. FIG. 34 is a front perspective view of the lens barrel extended state, FIG. 34 is a rear perspective view, and FIG. 35 is an explanatory block diagram illustrating a schematic configuration of the digital still camera shown in FIG.

  A lens barrel 1 shown in FIGS. 1 to 4 shows a first embodiment of the lens barrel of the present invention, and includes a photographing optical system composed of a plurality of optical elements such as lenses and filters, It consists of a mechanic system such as a ring or a frame that supports each component of the photographing optical system so as to be fixed or movable, and a power system such as a motor or gear that operates the mechanic system.

  As shown in FIGS. 2 to 4, the imaging optical system of the lens barrel 1 includes a first lens group 2 composed of a combination of a plurality of lenses arranged in order from the subject side, and an automatic exposure that is a shutter and an iris unit. The apparatus 3 includes a second lens group 4 composed of a combination of a plurality of lenses, a third lens group 5 composed of a combination of one or more lenses, a low-pass filter 6, an image sensor (CCD) 7, and the like. ing. The zoom function is exhibited by the first lens group 2 and the second lens group 4, and the zooming operation of the optical system can be executed by moving both the lens groups 2 and 4 by a predetermined amount in the optical axis direction. The focusing function is exhibited by the third lens group 5, and the focusing operation of the optical system can be executed by moving the third lens group 5 by a predetermined amount in the optical axis direction.

  The mechanic system of the lens barrel 1 includes, in order from the subject side, a first group ring 10 showing a first specific example of a rectilinear member, a first group lens frame 11 that holds the first lens group 2, and a second rectilinear member. A second group ring 12 showing a specific example, a second group lens frame 13 holding the second lens group 4, a rectilinear ring 14, a cam ring 15 showing a specific example of a rotating member, and a camera such as a digital still camera A fixed ring 16 fixed to the main body, a third group lens frame 17 holding the third lens group 5, a rear barrel 18 fixed to the rear part of the fixed ring 16, and the like. A CCD unit 20 having an image sensor (CCD) 7 is attached to the rear barrel 18.

  The power system of the lens barrel 1 includes a reduction gear unit 21 and a drive gear 22 that rotate the cam ring 15, an F motor unit 23 that performs a focusing operation of the optical system, and the like. The reduction gear unit 21 and the F motor unit 23 are attached to the assembly of the stationary ring 16 and the rear barrel 18. The drive gear 22 is rotatably supported by the fixed ring 16 and the rear barrel 18.

  The rear barrel 18 has a ring-shaped rear surface portion 18a in which a substantially rectangular through hole 25 is provided in the center portion, and an inner side that protrudes to one side so as to surround the through hole 25 of the rear surface portion 18a. A boss portion 18b and an outer boss portion 18c formed on one side of the outer surface of the rear surface portion 18a so as to protrude from the one surface side. A unit support portion for supporting the F motor unit 23 on a part of the outer boss portion 18c. 26 is provided. On the back side of the inner boss portion 18b of the rear barrel 18, a seat portion 18d is provided by denting the periphery thereof, and the CCD unit 20 is mounted on the seat portion 18d.

  As shown in FIGS. 2 to 4, the CCD unit 20 includes a CCD adapter 28 that holds a CCD (imaging device) 7 and other components, a seal rubber 29, a filter presser 30, and the like. The CCD 7 is fixed to the CCD adapter 28. The CCD adapter 28 is formed of a substantially rectangular frame that is fitted in the through hole 25 of the rear barrel 18, and the CCD 7 is fixed via a seal rubber 29 with the light receiving surface facing the central opening. Yes. A low-pass filter 6 is disposed in front of the light receiving surface of the CCD 7, and the low-pass filter 6 is clamped by a filter presser 30 made of a substantially rectangular frame and is detachably held on the CCD adapter 28. Reference numeral 31 shown in FIG. 2 is a flexible wiring board for the CCD 7.

  The fixed ring 16 fixed to the front part of the rear barrel 18 has a configuration as shown in FIG. The fixed ring 16 is formed of a substantially cylindrical cylinder that is an exterior body of the lens barrel 1, and all of the photographing optical system can be accommodated in the fixed ring 16. As shown in the development view of FIG. 6, the front surface portion 16a in the optical axis direction, which is one end surface of the fixed ring 16, is a flat portion perpendicular to the optical axis direction, but light that is the other end surface. The rear surface portion 16b in the axial direction is formed with irregularities by a predetermined step in the optical axis direction. The unevenness of the rear surface portion 16 b is provided so as to correspond to the unevenness of the joint portion of the rear barrel 18. Further, the fixed ring 16 is provided with a first notch 33 for exposing a part of the drive gear 22 and a second notch 34 for exposing a part of the third group lens frame 17. Yes.

  The first notch 33 and the second notch 34 of the fixed ring 16 are opened to the rear surface portion 16b. A bearing portion 16c that supports one end in the axial direction of a support shaft 35 that rotatably supports the drive gear 22 is provided on the outer surface of the fixed ring 16 corresponding to the first notch 33. A support portion 16 d that supports a part of the F motor unit 23 is provided on the outer surface of the stationary ring 16 corresponding to the second notch 34. Further, on the inner peripheral surface of the fixed ring 16, a total of three types of cam grooves 37A, 37B and 37C having substantially the same cam curve, and a total of five types of three types extending linearly in the optical axis direction. Straight guide grooves 38A, 38B, and 38C are provided.

  A total of three types of cam grooves 37A, 37B, and 37C of the fixed ring 16 are continuous with the inclined surface portion 37a spirally extending in the circumferential direction and the front surface portion 16a side of the inclined surface portion 37a and in the optical axis direction. The front horizontal portion 37b extending in the circumferential direction orthogonal to the surface and the rear surface portion 16b side of the inclined surface portion 37a is a circumferential direction orthogonal to the optical axis direction and opposite to the front horizontal portion 37b. And a rear horizontal portion 37c extending in the direction. A central protrusion 39 is provided on each inclined surface portion 37a of the two first cam grooves 37A and 37B of the first type so as to divide the width direction into two. A right passage 39a and a left passage 39b extending in parallel with each other are formed in the slope portion 37a by the central protrusion 39.

  A total of three cam grooves 37A to 37C including two first cam grooves 37A and 37B provided with such a structural difference and one second cam groove 37C of the second type are provided. They are arranged at substantially equal intervals in the circumferential direction on a plane perpendicular to the optical axis direction. Three cam followers (described later) provided in the cam ring 15 are slidably engaged with the three types of cam grooves 37 </ b> A to 37 </ b> C in total of two types having such a configuration.

  On the other hand, a total of three types of five rectilinear guide grooves 38A, 38B, 38C are arranged in parallel with each other at an appropriate interval in the circumferential direction on a plane perpendicular to the optical axis direction. . The two first rectilinear guide grooves 38A, 38A that are the first type guide the rectilinear ring 14 and the rotation restricting member 80 in the optical axis direction. The two first rectilinear guide grooves 38A, 38A are slidably engaged with cam followers, which will be described later, provided on the rectilinear ring 14, and convex portions, which will be described later, provided on the rotation restricting member 80. Is done. The two first rectilinear guide grooves 38A and 38A are arranged at predetermined intervals on one side (left side in FIG. 6) of the first cam grooves 37A and 37B, respectively. The two first rectilinear guide grooves 38A, 38A are provided so as to intersect with the front horizontal portions 37b of the first and second cam grooves 37A, 37B, respectively.

  On the other hand, the three second rectilinear guide grooves 38B, 38B, 38C, which are the second type, together with the two first rectilinear guide grooves 38A, 38A, guide the rectilinear ring 14 in the optical axis direction. is there. Of the three second rectilinear guide grooves 38B, 38B, 38C, the two second rectilinear guide grooves 38B, 38B are provided so as to intersect with the inclined surface portions 37a of the two cam grooves 37A, 37B, respectively. Thus, each slope portion 37a is provided with a cut-out portion 41 that divides the central protrusion 39 in an oblique direction. On the other hand, the remaining one second rectilinear guide groove 38C is provided. Similarly to the first rectilinear guide groove 38A, it is provided so as to intersect with the front horizontal portion 37b of the third cam groove 37C.

  The stationary ring 16 having such a configuration is disposed on the front side of the rear barrel 18 and is detachably fixed by a plurality of fixing screws. A support shaft 35 is held by a lens barrel assembly of the fixed ring 16 and the rear lens barrel 18, and some teeth of the drive gear 22 rotatably supported by the support shaft 35 have a tooth width. It is exposed to the outside of the lens barrel assembly from the first notch 33 over substantially the entire length in the direction. The reduction gear unit 21 is detachably attached to the bearing portion 16c of the fixed ring 16 and the flange portion of the rear barrel 18 so as to cover the exposed portion of the drive gear 22, and is fastened and fixed with a plurality of fixing screws. Has been.

  As shown in FIG. 2, the reduction gear unit 21 includes an output gear (not shown) meshed with the drive gear 22, one or more reduction gears that transmit power to the output gear, and power via the reduction gear. The zoom motor 44 that rotates the output gear by transmitting the output gear, and the housing 45 that rotatably supports the output gear and other gears, and that supports the zoom motor 44 fixedly. The housing 45 is fastened and fixed to the barrel assembly with a fixing screw, so that the reduction gear unit 21 is attached so as to be assembled and disassembled. The reduction gear unit 21 is provided with a rotation detector such as a rotary encoder that detects the number of rotations of the zoom motor 44 and outputs a detection signal thereof.

  The unit support portion 26 of the rear barrel 18 includes a pair of support pieces that support the F motor unit 23 so as to hold the F motor unit 23, and the pair of support pieces protrude forward so as to be substantially parallel with an appropriate gap. Has been. The F motor unit 23 held by the unit support portion 26 and the support portion 16d of the fixed ring 16 serves as a power source for causing the lens barrel 1 to perform a focusing operation. The F motor unit 23 includes a focus motor 46, a motor bracket 47 that fixes and supports the focus motor 46, a carriage 48 that is movably screwed to a rotation shaft 46a of the focus motor 46, and the carriage 48 that is a rotation shaft. The guide bar 49 etc. which guide substantially parallel to the axial direction of 46a are comprised.

  The motor bracket 47 is formed in a U-shape, and the focus motor 46 is fixed to the outside of one rising piece. The rotation shaft 46a of the focus motor 46 is composed of a feed screw shaft, and the rotation shaft 46a passes through one rising piece, and its tip is rotatably supported by the other rising piece. Between the rising pieces, a carriage 48 is screwed onto the rotary shaft 46a so as to be movable in the axial direction. A guide bar 49 having a shaft center line set substantially parallel to the shaft center line of the rotating shaft 46a is slidably passed through the carriage 48. Both end portions of the guide bar 49 in the axial direction are supported by the motor bracket 47, and the carriage 48 is guided by the guide bar 49 so as to be movable back and forth in the optical axis direction.

  The third lens group 5 can be moved back and forth in the optical axis direction by the F motor unit 23 having such a configuration. The third lens group 5 is disposed in front of the low-pass filter 6 disposed in front of the CCD 7 and is held by a third group lens frame 17. The third group lens frame 17 includes a lens holding portion 17a that holds the third lens group 5, and an arm portion 17b that is continuous to one side of the lens holding portion 17a. The arm portion 17 b is provided with a sliding bearing portion 17 c through which the guide shaft 51 is slidably inserted, and an engaging portion 17 d that is engaged with the carriage 48 of the F motor unit 23.

  One end of a third group spring 52 made of a coil spring is engaged with the third group lens frame 17. The other end of the third group spring 52 is locked to the fixed ring 16, and the engaging portion 17 d of the third group lens frame 17 is always pressed against the carriage 48 by an appropriate urging force by the spring force of the third group spring 52. It has been. Thus, when the focus motor 46 of the F motor unit 23 is rotationally driven, the carriage 48 is guided by the guide bar 49 against the spring force of the third group spring 52 according to the rotational direction, and advances and retreats in the optical axis direction. Moving. As a result, the third lens group 5 moves by a predetermined amount in the optical axis direction according to the rotation amount of the F motor unit 23, whereby a predetermined focusing operation is executed.

  A cam ring 15 is disposed inside the fixed ring 16. The cam ring 15 has a configuration as shown in FIGS. The cam ring 15 includes a cylindrical body portion 15a having an outer diameter slightly smaller than the inner diameter of the fixed ring 16, and a flange portion 15b continuous to one end face side of the body portion 15a. The flange portion 15b is in the radial direction. Expanded outward. The flange portion 15b includes an arc-shaped first flange portion 54a that occupies a portion extending over approximately half of the circumferential direction, and an arc-shaped second flange disposed on the opposite side so as to face the first flange portion 54a. The flange portion 54b. The second flange portion 54b is formed as a region that occupies a portion extending over approximately 1/6 in the circumferential direction, and the second flange portion 54b is located on both sides of the circumferential direction and between the first flange portion 54a and the second flange portion 54b. A first cutout portion 55a and a second cutout portion 55b having the same size as the flange portion 54b are provided.

  As shown in FIGS. 8A and 8B, the flange portion 15b of the cam ring 15 is provided with three cam protrusions 57A, 57B, and 57C showing the first embodiment of the cam follower. The three cam projections 57A, 57B, and 57C are arranged at substantially equal intervals in the circumferential direction, and the first cam projection 57A is provided on one side of the first flange portion 54a, and the second cam projection The portion 57B is provided on the other side of the first flange portion 54a, and the third cam projection 57C is provided on the second flange portion 54b. Of the three cam projections 57A to 57C, engagement grooves 58 extending in an oblique direction are provided at the tips of the first and second cam projections 57A and 57B, respectively.

  The three cam protrusions 57A to 57C are slidably engaged with three cam grooves 37A, 37B, and 37C provided on the inner peripheral surface of the fixed ring 16. The three cam protrusions 57A to 57C are formed so as to correspond to the three cam grooves 37A, 37B, and 37C, and the respective engagement grooves provided in the first and second cam protrusions 57A and 57B. 58, the central protrusions 39 provided in the first and second cam grooves 37A and 37B are respectively slidably engaged. As described above, the central protrusion 39 is provided on the wide slope portion 37a of the cam grooves 37A and 37B to form the left and right passages 39a and 39b, so that the second linear guide extending in a direction intersecting with the left and right passages 39a and 39b. Even if the groove 38B is notched in the inclined surface portion 37a of the cam groove, the first and second cam projections 57A and 57B of the cam ring 15 remain along the cam grooves 37A and 37B while maintaining the cam engagement. You can move smoothly.

  The three cam protrusions 57A to 57C are set on the same plane perpendicularly intersecting the axial center line of the body part 15a. However, as shown in FIGS. 7A and 7B, only the third cam protrusion 57C is provided. Is formed thinner than the other cam projections 57A and 57B. A gear portion 60 formed of spur teeth is provided on the first flange portion 54a of the flange portion 15b so as to surround the third cam protrusion 57C. The gear portion 60 is continuous to one side in the circumferential direction of the first cam projection 57A and has the same gear width on the outer side in the axial direction of the third cam projection 57C. The second gear portion 60b formed with the same tooth width as that of the first gear portion 60a and the first gear portion 60a and the second gear portion 60b are connected to each other and have a combined tooth width. It consists of a third gear portion 60c.

  The drive gear 22 is always meshed with the gear portion 60 at any one of the gear portions 60a to 60c. Thereby, when the drive gear 22 is rotationally driven by the operation of the reduction gear unit 21, the cam ring 15 is rotated to the left or the right according to the rotation direction. The circumferential length of the gear portion 60 has the number of teeth necessary for the cam ring 15 to rotate by a predetermined angle. Therefore, when the cam ring 15 is rotated by the drive gear 22, the cam ring 15 simultaneously moves in the axial direction, but the drive gear is larger than the movement amount (stroke) of the cam ring 15 in the axial direction. Since the tooth width of 22 is set to be sufficiently long, the rotation operation within a predetermined range is executed in a state where the drive gear 22 and the gear portion 60 are always meshed.

  Further, a fin 61 for detecting the rotational position between the cams 5 is provided on the first flange portion 54a of the flange portion 15b of the cam ring 15. The fin 61 is formed to have a predetermined length in the circumferential direction continuously to the end of the first flange portion 54a on the third cam protrusion 57C side. Although not shown, the rear lens barrel 18 is provided with a photosensor to detect the fins 61. When the photosensor is switched by the movement of the fin 61, the rotational position of the cam ring 15 can be detected. Based on the rotational position information obtained by the rotational position detecting means and the detection information obtained by the rotary encoder provided in the reduction gear unit 21 described above, the information is processed by a control device described later, whereby the cam ring 15 is processed. It is possible to control the rotation speed and the rotation position.

  Furthermore, the first flange portion 54a of the flange portion 15b of the cam ring 15 is provided with a through hole 62 that passes through the first flange portion 54a in the tooth width direction. The through hole 62 is formed in an arc shape so as to be concentric with the outer peripheral surface of the body portion 15a or the teeth of the gear portion 60 at a position opposite to the second flange portion 54b. The end portion of the body portion 15a facing the through hole 62 is formed in the same manner as the shapes of the first and second cutout portions 55a and 55b, as will be described later.

  Three outer cam grooves 65 having the same cam curve (trajectory) are provided on the outer periphery of the body portion 15 a of the cam ring 15. The three outer cam grooves 65 are arranged at substantially equal intervals in the circumferential direction, enable operation in the optical axis direction of the first group frame 10 that supports the first lens group 2, and perform optical zooming operation on the lens barrel 1. The lens barrel storage operation is given. As shown in FIGS. 7A, 7B, and 9A, the three outer cam grooves 56 include a lens barrel storage operation region 66 that imparts a lens barrel storage operation, and a zooming operation region 67 that is continuous with the lens barrel storage operation region 66. It consists of and. The lens barrel storing operation area 66 of the outer cam groove 65 is spirally extended in an oblique direction with an inclination angle of about 45 degrees on the outer peripheral surface of the body portion 15a. One end of the lens barrel storage operation region 66 is opened at the end of the body portion 15a on the flange portion 15b side, and one end of the zooming operation region 67 is continuous with the other end.

  The zooming operation area 67 of the outer cam groove 65 is a zoom groove 67a formed of a groove formed in an arc shape by a predetermined curve, and a groove that gently communicates one end of the zoom groove 67a and the lens barrel storage operation area 66. A communicating portion 67b and a closing portion 67c or an opening portion 67d comprising a groove that is closed at the other end of the body portion 15a opposite to the flange portion 15b (on the opposite flange side). Have. The zoom groove portion 67a of the zooming operation region 67 is formed so as to protrude toward the flange portion 15b on the opposite flange side of the body portion 15a. The communication portion 67b of the zooming operation region 67 is formed by a groove in which a plurality of straight portions are gently continued. Moreover, the closing part 67c and the open part 67d are formed of grooves that are continuous in the circumferential direction.

  In order to form the communication portion 67b and the closing portion 67c or the opening portion 67d, three types of protrusions 68a, 68b, and 68c are provided on the opposite side of the body portion 15a. The three first protrusions 68a provided to correspond to the communication portion 67b are formed of trapezoidal portions having inclined surfaces on both sides. In addition, one second projecting portion 68b provided corresponding to the closing portion 67c and two third projecting portions 68c, 68c provided corresponding to the open portion 67d have inclined surfaces only on one side. It has a trapezoidal part. On the other hand, the two third projecting portions 68c and 68c are configured such that the cam groove is located on the end surface side of the body portion 15a by setting the vertical surface to the middle portion of the cam groove, as shown by a two-dot chain line in FIG. 9A. To open.

  An opening end of the outer cam groove 65 on the side of the flange portion 15b in the lens barrel storing operation region 66 forms a groove opening portion 71 through which a cam follower, which will be described later, of the first group ring 10 enters and exits. A pressing portion 72 that presses the cam follower of the first group ring 10 and transmits the rotational force of the cam ring 15 to the first group ring 10 is provided outside the side surface of one cam groove that forms the cam groove opening 71. It has been. Furthermore, a holding portion 73 that holds the cam follower at a position away from the outer cam groove 65 is provided on the opposite side of the cam groove opening 71 from the pressing portion 72.

  As shown in FIGS. 7A, C, and 9B, three sets of inner cam groove groups 74 having the same cam curve (trajectory) are arranged at equal intervals in the circumferential direction on the inner periphery of the body portion 15a of the cam ring 15. Has been provided. The three sets of inner cam groove groups 74 are composed of a combination of a front inner cam groove 75 and a rear inner cam groove 76 having the same cam curve (trajectory), and two groups that support the second lens group. The operation of the frame 12 in the optical axis direction is enabled, and the lens barrel 1 is provided with an optical zooming operation and a barrel storage operation. The front inner cam groove 75 and the rear inner cam groove 76 are set at a predetermined distance in the axial direction of the body portion 15a, which is the optical axis direction, and also slightly deviated in the circumferential direction. Are provided in a slightly twisted state.

  The basic cam curve of the front inner peripheral cam groove 75 and the rear inner peripheral cam groove 76 includes a first inclined surface portion 77a inclined in the same direction as the lens barrel storing operation region 66 of the outer cam groove 65, and its first A second inclined surface portion 77b inclined to the opposite side of the first inclined surface portion 77a, a horizontal portion 77c continuously extending in the circumferential direction at one end of the first inclined surface portion 77a and one end of the second inclined surface portion 77b, An open portion 77d continued to the other end of the slope portion 77a, and a circulation portion 77e continued to the other end of the second slope portion 77b. The first inclined surface portion 77a is inclined at an angle of approximately 45 degrees, but the midway portion is slightly bent rearward. Further, the first inclined surface portion 77a has a predetermined cam curve so that the second group frame 12 advances and retracts in conjunction with the first group frame 10 that advances and retracts in the optical axis direction by the zoom groove portion 67a of the outer cam 65. The second inclined surface portion 77b and the circulation portion 77e provide the lens barrel storage operation of the second group frame 12, and are connected by a connection portion curved to the front side, and move in the circumferential direction within the circulation portion 77e. It is the structure which returns to 2 slope part 77b.

  The front inner peripheral cam groove 75 and the rear inner peripheral cam groove 76 having such a basic cam curve are the front inner peripheral cam groove 75, most of the first slope portion 77 a, the horizontal portion 77 c, and the second portion. The slope portion 77b and the circulation portion 77d are provided. On the other hand, the rear inner peripheral cam groove 76 is composed of only a part of the first slope portion 77a and the opening portion 77d. That is, the first inclined surface portion 77a of the front inner peripheral cam groove 75 is opened at the end face of the protruding portion 68b in the first inner cam groove group 74, and protrudes in the second and third inner cam groove groups 74. Opened on the side surfaces of the portions 68c, 68c. A part of the horizontal portion 77c of the front inner circumferential cam groove 75 is opened on the flange-side end surface of the body portion 15a.

  Further, the rear inner peripheral cam groove 76 is provided with only an opening portion 77d and a portion of the first slope portion 77a on the opening portion 77d side. That is, one end of the opening portion 77d is opened on the end surface on the opposite side of the body portion 15a, and one end of the first inclined surface portion 77a is opened on the end surface on the flange side of the body portion 15a. In addition, each opening portion of the front inner peripheral cam groove 75 and the rear inner peripheral cam groove 76 is provided with an introductory portion 78 that widens toward the end in order to facilitate the entry and exit of the follower cam.

  A rotation restricting member 80 that is rotatable in the rotation direction but restricted so as not to move in the optical axis direction is fitted into the flange portion 15b of the cam ring 15 having such a configuration. As shown in FIGS. 2 and 10, the rotation restricting member 80 includes a ring portion 80a having a ring shape having an outer diameter and an inner diameter substantially the same as the outer diameter and inner diameter of the body portion 15a, and an inner portion of the ring portion 80a. It has two rectilinear guide pieces 80b and 80b that are continuous to the periphery, and two convex part pieces 80c and 80c that are continuous to the outer periphery of the ring portion 80a. On the outer periphery of the ring portion 80a of the rotation restricting member 80, three notches 81 for avoiding contact with a cam follower of the first group ring 10 described later are provided at equal intervals in the circumferential direction.

  The two rectilinear guide pieces 80b and 80b of the rotation restricting member 80 are disposed so as to face the position rotated and rotated by 180 degrees, and are formed to project in a direction perpendicular to the surface direction of the ring portion 80a. . The two rectilinear guide pieces 80b and 80b are slidably engaged with two rectilinear guide grooves (to be described later) of the second group ring 12. The two convex pieces 80c, 80c are formed so as to protrude outward in the radial direction with a predetermined interval in the circumferential direction. The two convex pieces 80c and 80c are slidably engaged with the above-described two first rectilinear guide grooves 38A and 38A of the fixed ring 16. As shown in FIGS. 7C and 8B, a ring-shaped seat portion 15c is provided on the inner periphery of the flange portion 15b of the cam ring 15 to accommodate the ring portion 80a of the rotation restricting member 80 in a rotatable manner. ing.

  On the inner periphery of the cam ring 15, a second group ring 12 whose rotational movement is restricted by a rotation restricting member 80 and is movable only in the optical axis direction is mounted. As shown in FIGS. 12 and 13, the second group ring 12 has a cylindrical cylindrical body portion 12 a and an inner flange portion that is developed radially inward in an axially middle portion of the cylindrical body portion 12 a. And a group lens frame 12b. A boss portion 12c is provided on the inner periphery of the second group lens frame 12b of the second group ring 12, and a second lens group 4 made of a combination of a plurality of lenses is attached to the boss portion 12c.

  On the outer periphery of the cylindrical body portion 12a of the second group ring 12, there are provided two rectilinear guide grooves 83, 83 in which the two rectilinear guide pieces 80b, 80b of the rotation restricting member 80 are slidably engaged. Yes. The two rectilinear guide grooves 83 and 83 are arranged at positions that are rotated and displaced by 180 degrees, and are formed in a straight line so as to be parallel to the optical axis direction. Further, three sets of cam pin groups 84 that are slidably engaged with three sets of inner cam groove groups 74 provided on the inner periphery of the cam ring 15 are provided on the outer periphery of the cylindrical portion 12a. The three sets of cam pin groups 84 have the same height in the optical axis direction and are arranged at equal intervals in the circumferential direction.

  Each cam pin group 84 is composed of a front cam pin 85 and a rear cam pin 86 arranged in the front and rear direction in the optical axis direction. The front cam pin 85 and the rear cam pin 86 are provided with a slight deviation in the circumferential direction. The front cam pin 85 of the cam pin group 84 is engaged with the front inner peripheral cam groove 75 of the inner cam groove group 74, and the rear cam pin 86 is engaged with the rear inner peripheral cam groove 76. At this time, while the two rectilinear guide grooves 83 and 83 provided on the outer periphery of the second group ring 12 are engaged with the two rectilinear guide pieces 80b and 80b of the rotation restricting member 80, the rotation restricting member 80 is provided. The two convex pieces 80c, 80c are slidably engaged with the two first straight guide grooves 38A, 38A of the stationary ring 16. Therefore, when the cam ring 15 is rotated, the second group ring 12 does not rotate with respect to the fixed ring 16, and the inner cam groove group 74 set by the front inner cam groove 75 and the rear inner cam groove 76. It moves forward and backward only in the optical axis direction along the cam curve.

  The operation of the second group ring 12 and the cam ring 15 by the cam mechanism is as follows. A state in which the second group ring 12 is completely accommodated in the cam ring 15 is a non-photographing state of the imaging apparatus. At this time, the front cam pin 85 is positioned in the circulating portion 77e of the front inner peripheral cam groove 75, while the rear cam pin 86 protrudes rearward from the body portion 15a and is not engaged with the rear inner cam groove 76. When the cam ring 15 is rotated in the feeding direction from this non-photographing state, the front cam pin 85 moves from the circulating portion 77e to the second inclined surface portion 77b due to the engagement between the front inner peripheral cam groove 75 and the front cam pin 85. . As a result, the second group ring 12 moves back and forth in the optical axis direction without rotating.

  When the cam ring 15 is further rotated in the feeding direction, the front cam pin 85 moves on the second inclined surface portion 77b and reaches the horizontal portion 77c. As a result, the cam engagement between the front cam pin 85 and the front inner peripheral cam groove 75 is released, but one end of the second group ring 12 is brought into contact with the rotation restricting member 80, so that the front cam pin 85 is moved to the front inner peripheral cam groove 75. Will not fall out completely. When the cam ring 15 is continuously rotated in the feeding direction, the front cam pin 85 enters the first inclined surface portion 77a, and the front cam pin 85 is cam-engaged with the front inner peripheral cam groove 75 again. When the cam ring 15 is further rotated, the rear cam pin 86 approaches the rear inner peripheral cam groove 76, and then the cam pin 86 is cam-engaged with the rear inner peripheral cam groove 76. As a result, the front and rear cam pins 85 and 86 are cam-engaged with the front and rear inner circumferential cam grooves 75 and 76.

  When the cam ring 15 is further rotated in the feeding direction, the second group ring 12 advances greatly and the front cam pin 85 passes through the first inclined surface portion 77a, so that the cam engagement between the front cam pin 85 and the front inner peripheral cam groove 75 occurs. The match will be missed. However, in this case, the rear cam pin 86 is cam-engaged with the rear inner peripheral cam groove 76, thereby ensuring further cam engagement. Therefore, the second group ring 12 can be further moved forward by cam engagement of only the rear cam pin 86 and the rear inner peripheral cam groove 76. At this time, since the front end and the rear end of the front inner peripheral cam groove 75 and the opening portion of the rear end of the rear inner peripheral cam groove 76 are provided with an introduction portion 78 which is widened toward the end, the front cam pin 85 and the rear The switching operation when the cam engagement of the cam pin 86 is switched can be performed smoothly. Note that the movement when changing from the shooting state to the non-shooting state is the reverse of the above-described operation.

  An automatic exposure apparatus 3 is attached to the front of the second group ring 12 so as to be movable by a predetermined distance in the optical axis direction while restricting movement in the rotation direction. The automatic exposure device 3 is an optical device having a function of a shutter that opens and closes an optical path through which light passes, a function of a variable aperture that changes the diameter of the optical path, and a filter function that moves a filter in and out of the optical path. As shown in FIG. 12, the automatic exposure apparatus 3 includes a ring-shaped hollow holder 88, and a shutter blade, an aperture blade, and a filter blade are placed in three directions of the hole so as to surround the central hole. Has been placed. On the outer surface of the holder 88, three guide projections 89 are provided at equal intervals in the circumferential direction.

  Three projection receiving portions 91 corresponding to the three guide projections 89 of the automatic exposure apparatus 3 are provided. By engaging the guide protrusions 89 with the protrusion receiving portions 91, the automatic exposure apparatus 3 can be moved forward and backward in the optical axis direction by the gap in the protrusion receiving portion 91. Further, between the automatic exposure apparatus 3 and the second group ring 12, a plurality of compression coil springs 92 showing a specific example of an elastic member that biases them in the direction of separating them from each other are interposed. The position where the plurality of compression coil springs 92 are most extended and the automatic exposure apparatus 3 is farthest from the second group ring 12 is the position in the photographing state. Conversely, the plurality of compression coil springs 92 are most contracted. Thus, the position where the automatic exposure apparatus 3 is closest to the second group ring 12 is the position in the non-photographing state.

  In the non-photographing state, the boss portion 12c of the second group ring 12 enters the central hole 88a of the holder 88 of the automatic exposure apparatus 3. Therefore, the diameter of the central hole 88a is set larger than the diameter of the boss portion 12c. Furthermore, the front end surface of the boss portion 12 c is configured to penetrate the central hole 88 a and be substantially flush with the front surface of the holder 88. For this reason, in the non-photographing state, the shutter function, variable aperture function, and filter function blades of the automatic exposure device 3 need to be retracted outward from the central hole 88a. In order to ensure such a function, a gap regulating member 94 is interposed between the automatic exposure apparatus 3 and the second group ring 12.

  The interval regulating member 94 has a configuration as shown in FIG. The spacing regulating member 94 includes a ring portion 94a that is rotatably fitted to the boss portion 12c of the second group ring 12, and a lever portion 94b that is formed so as to protrude radially outward from the outer periphery of the ring portion 94a. have. A cam projection 94c extending in a direction perpendicular to the surface direction of the ring portion 94a is provided at the tip of the lever portion 94b. The cam projection 94c protrudes to the opposite side of the automatic exposure device 3 through a hole provided in the second group lens frame 12b in a state in which the interval regulating member 94 is assembled to the second group ring 12. The interval regulating member 94 is constantly urged in a predetermined rotational direction by a torsion spring 95 showing a specific example of the elastic member.

  Further, the ring portion 94a of the interval regulating member 94 is provided with three stopper portions 94d that prevent the automatic exposure apparatus 3 and the second group ring 12 from approaching a predetermined level. The three stopper portions 94d are arranged at substantially equal intervals in the circumferential direction on the surface of the ring portion 94a opposite to the side from which the cam projection 94c projects. When the lens barrel 1 is in front of the non-photographing state, the cam projection 94c of the interval regulating member 94 is in contact with a cam projection 18e that protrudes forward provided on the rear surface portion 18a of the rear barrel 18. From this state, when the lens barrel 1 is further moved in the non-photographing state, the distance regulating member 94 is rotated by a predetermined amount according to the cam surface of the cam projection 94c and the cam surface of the cam projection 18e.

  As a result, the interval regulating member 94 rotates by a predetermined amount, so that the three stopper portions 94d are retracted to a position where the stopper surface (not shown) provided in the automatic exposure apparatus 3 does not exist. The interval restriction of the second group frame 12 is released. As a result, since the automatic exposure apparatus 3 can move in a direction approaching the second group ring 12, it is possible to store the automatic exposure apparatus 3 in the second group ring 12 and shorten the length in the optical axis direction. On the other hand, in the photographing state, the three stopper portions 94d of the interval regulating member 94 are interposed between the automatic exposure apparatus 3 and the second group ring 12. Therefore, the interval between the automatic exposure apparatus 3 and the second group ring 12 can be regulated by the stopper portion 94d, and the interval can be prevented from becoming unnecessarily narrow.

  With such a configuration, even when an inadvertent external force or impact may be applied to the lens barrel 1 in the photographing state, the interval between the automatic exposure device 3 and the second group ring 12 is narrowed to a predetermined value or more. There is nothing. Therefore, it is possible to prevent the automatic exposure apparatus 3 from being pressed against the second group ring 12, thereby protecting the shutter function, variable aperture function, and the like of the automatic exposure apparatus 3. Moreover, the thickness from the second group ring 12 to the automatic exposure device 3 can be made thinner in the non-photographing state than in the photographing state.

  As shown in FIGS. 2 and 3, the first group ring 10 is relatively rotatably attached to the outer periphery of the body portion 15 a of the cam ring 15. As shown in FIGS. 2 and 14 and the like, the first group ring 10 includes a cylindrical body portion 10a into which the body portion 15a is inserted, and an axial end of the cylindrical body portion 10a. The outer flange portion 10b is expanded, and the inner flange portion 10c is continuous to the front side which is the other end in the axial direction of the cylindrical portion 10a and is expanded radially inward. Furthermore, three brackets 10d projecting rearward in the optical axis direction are provided on the cylindrical body portion 10a of the first group ring 10 at equal intervals in the circumferential direction.

  Each of the three brackets 10d is provided with a guide convex portion 97 protruding outward in the radial direction and a cam pin 98 showing a specific example of a cam follower protruding inward in the radial direction. The guide convex portion 97 and the cam pin 98 are arranged so as to overlap each other at the same position. However, the guide convex portion 97 is integrally formed so as to build up a part of the bracket 10d. It is provided integrally by press-fitting the member. That is, the guide convex portion 97 is formed of a block-like portion extending in the optical axis direction, and the three guide convex portions 97 are slidably engaged with a linear guide groove (described later) of the linear ring 14. .

  The three cam pins 98 are cam followers that are slidably engaged with the three outer cam grooves 65 provided on the outer periphery of the body portion 15 a of the cam ring 15. The cam pin 98 includes a pin head 98a that is slidably contacted with the outer cam groove 65, a fixing portion 98b that is press-fitted into the mounting hole of the bracket 10d, and a flange provided between the fixing portion 98b and the pin head 98a. Part 98c. The flange portion 98c has a role of restricting the press-fitting depth of the fixing portion 98b and holding the protruding amount of the pin head portion 65a at a predetermined value. An operation surface 99 with which the pressing portion 72 of the cam ring 15 is brought into contact is provided on one side surface of the bracket 10d provided with the cam pins 98 and the like. The operation surface 99 is set to an inclination angle corresponding to the inclined surface of the pressing portion 72, and is approximately 45 degrees, for example.

  The first group ring 10 is mounted on the inner circumference of the straight ring 14 so as to be movable only in the optical axis direction while restricting movement in the rotational direction. As shown in FIGS. 2 and 11, the rectilinear ring 14 is provided at one end in the optical axis direction of the cylindrical portion 14 a into which the first group ring 10 is inserted, and is expanded outward in the radial direction. And an outer flange portion 14b. The outer flange portion 14b is provided with five protrusions 14c that are slidably engaged with the five rectilinear guide grooves 38A, 38A, 38B, 38B, and 38C provided on the inner periphery of the fixed ring 16. ing. The five protrusions 14c are arranged at positions corresponding to the five rectilinear guide grooves 38A, 38A, 38B, 38B, 38C. The five rectilinear guide grooves 38A, 38A, 38B, 38B, and 38C of the stationary ring 16 all intersect with the cam grooves 37A, 37B, and 37C, but all five positions in the optical axis direction are the same at the five intersections. Therefore, at any position in the optical axis direction, the five protrusions 14c of the rectilinear ring 14 and the five rectilinear guide grooves 38A, 38A, 38B, 38B, 38C of the fixed ring are engaged at the same time. As a result, the rectilinear ring 14 can move forward and backward in the optical axis direction smoothly with respect to the fixed ring 16. That is, at the position in the optical axis direction where the two rectilinear guide grooves 38B and 38B of the fixed ring 16 intersect with the cam grooves 37A and 37B, two of the five projecting portions 14c of the rectilinear ring are engaged. The remaining three remain engaged in the rectilinear guide grooves 38A, 38A, 38C, while the three rectilinear guide grooves 38A, 38A, 38C of the stationary ring 16 intersect with the cam grooves 37A, 37B, 37C. At the position in the optical axis direction, the engagement of three of the five protrusions 14c of the rectilinear ring is lost, and the remaining two maintain the engagement in the rectilinear guide grooves 38B and 38B.

  Three rectilinear guide grooves 101 are provided on the inner periphery of the cylindrical portion 14a of the rectilinear ring 14 so that the three guide convex portions 97 provided on the outer periphery of the first group ring 10 are slidably engaged. Yes. The three rectilinear guide grooves 101 are arranged at substantially equal intervals in the circumferential direction and extend linearly in the optical axis direction in parallel with each other. Each straight guide groove 101 has an end on the outer flange portion 14b side opened in the end surface of the cylindrical body portion 14a, and an end on the opposite side is interrupted in the middle in the optical axis direction. As a result, the first group ring 10 can be moved in and out on the outer flange portion 14b side with respect to the rectilinear ring 14, but is dead end on the distal end side on the opposite outer flange portion 14b side. Is configured not to fall off.

  On the outer periphery of the rectilinear ring 14, a decorative ring 102 for the rectilinear ring 14 for mainly adjusting the appearance of the lens barrel 1 is attached and integrally configured. With the decorative ring 102 attached, the rectilinear ring 14 is attached to the inner periphery of the stationary ring 16. A cam ring 15 is attached to the inner periphery of the rectilinear ring 14 attached to the inner periphery of the fixed ring 16.

  That is, three cam pins 98 provided on the inner periphery of the first group ring 10 are slidably engaged with the three outer cam grooves 74 provided on the outer periphery of the cam ring 15. The three guide convex portions 97 provided on the outer periphery of the first group ring 10 are slidably engaged with the three rectilinear guide grooves 101 provided on the inner periphery of the rectilinear ring 14, respectively. Further, the five protrusions 14c projecting on the outer periphery of the rectilinear ring 14 are slidably engaged with the five rectilinear guide grooves 38A, 38A, 38B, 38B, 38C provided on the inner periphery of the fixed ring 16, respectively. Has been. At the same time, the three cam projections 57A to 57C provided on the flange portion 15b of the cam ring 15 are slidable in the three cam grooves 37A, 37B, and 37C provided on the inner periphery of the fixed ring 16, respectively. Is engaged. Further, the two convex pieces 80c of the rotation restricting member 80 held by the cam ring 15 are slidably engaged with the two rectilinear guide grooves 38A and 38A provided on the inner periphery of the fixed ring 16, respectively. ing.

  Thus, the rectilinear ring 14 and the rotation restricting member 80 are rotated while the five protrusions 14c of the rectilinear ring 14 are engaged with the five rectilinear guide grooves 38A, 38A, 38B, 38B, 38C of the fixed ring 16. Since the two convex pieces 80 c of the restricting member 80 are engaged with the two rectilinear guide grooves 38 A and 38 A of the fixed ring 16, the cam ring 15 does not rotate relative to the fixed ring 16. Are moved together in the optical axis direction by a distance that moves in the optical axis direction. In addition, since the three guide protrusions 97 of the first group ring 10 are engaged with the three rectilinear guide grooves 101 of the rectilinear ring 14, the first group ring 10 depends on the amount of rotation of the cam ring 15. It moves forward and backward in the direction of the optical axis without rotating. The first group ring 10 and the second group ring 12 are urged so as to be attracted to each other in the optical axis direction by a plurality of coil springs 103 showing a specific example of the elastic member.

  The operation of the first ring 10 and the cam ring 15 by the cam mechanism is as follows. As shown in FIGS. 16A and 16B, FIGS. 17A and B, and FIGS. 18A and 18B, the state in which the first group ring 10 is completely accommodated in the cam ring 15 is a non-photographing state of the imaging apparatus. At this time, the rear end side of the outer cam groove 65 of the cam ring 15 is opened, and the cam pin 98 is positioned in the holding portion 73 of the opened cam groove opening 71 in the non-photographing state of the camera. The engagement with the outer cam groove 65 is released. When the cam ring 15 is rotated in the feeding direction from this state, the pressing portion 72 of the cam ring 15 hits the operation surface 99 of the bracket 10d of the first group ring 10, and the inclined operation surface 99 causes the first group ring 10 to move. Pushed up. By the push-up force of the cam ring 15, the first group ring 10 moves in the optical axis direction without rotating with respect to the fixed ring 16.

  Further, when the cam ring 15 is rotated to a position in the feeding direction, the cam pin 98 is engaged with the outer cam groove 65, and when the cam ring 15 is further rotated, the pressing portion 72 of the cam ring 15 and the operation surface 99 of the first group ring 10. The abutting state is released. Thereafter, according to the rotation amount of the cam ring 15, it moves forward and backward in the optical axis direction without rotating with respect to the fixed ring 16 along the cam curve (trajectory) of the outer cam groove 65. At this time, since the open end of the outer cam groove 65 has a divergent shape, the cam pin 98 can be reliably and easily engaged with the outer cam groove 65. Note that the movement when changing from the shooting state to the non-shooting state is the reverse of the above-described operation.

  As shown in FIGS. 2 and 14, the inner flange portion 10 c provided on the inner periphery of the first group ring 10 is provided with a plurality of step-like fixing portions 105 having different heights in the optical axis direction. . The first group lens frame 11 is held and fixed to the first group ring 10 by using a plurality of fixing portions 105 provided on the inner flange portion 10c. The first group lens frame 11 is made of a ring-shaped member fitted to the inner flange portion 10c, and the first lens group 2 made of a combination of a plurality of lenses is held on the inner periphery thereof. On the outer periphery of the first group lens frame 11, a plurality of sets (three sets in the present embodiment) of clamping projections 106 for fixing the first group lens frame 11 to the first group ring 10 are provided at substantially equal intervals in the circumferential direction. Yes.

  Each sandwiching protrusion 106 is a combination of a front protrusion 106a and a rear protrusion 106b provided with a predetermined gap in the front and rear in the optical axis direction, and the front protrusion 106a and the rear protrusion 106b are arranged slightly offset in the circumferential direction. Has been. The first group lens frame 11 is fixed to the first group ring 10 by sandwiching the fixing portion 105 of the inner flange portion 10c from the front and rear by a plurality of sets of holding protrusions 106 having such a configuration. In this fixed state, when the first group lens frame 11 is rotated in the circumferential direction, the first group lens frame 11 is moved forward and backward in the optical axis direction by the amount of the step according to the amount of rotation. Reference numeral 108 shown in FIG. 14 and the like is a decorative ring that covers the periphery of the first lens group 2.

  As shown in FIGS. 2 to 4, a lens barrier unit 110 is provided at the front end of the first group ring 10 to close the optical path that is a photographing aperture and protect the photographing optical system when not photographing. The lens barrier unit 110 includes a ring-shaped barrier body 110a, a pair of opening / closing blades 110b rotatably supported by the barrier body 110a, a blade opening / closing mechanism 110c for opening / closing the opening / closing blade 110b, and the like. Has been. The barrier body 110a is provided with a plurality of engaging claws 110d at substantially equal intervals in the circumferential direction. The lens barrier unit 110 is fixed to the first group ring 10 by engaging the engaging claws 110d with the inner periphery of the cylindrical portion 10a.

  Although not shown, the blade opening / closing mechanism 110c of the lens barrier unit 110 is provided with a drive arm that rotates the opening / closing blade 110b. The drive arm is configured to rotate by relative movement in the optical axis direction. Therefore, by rotating the drive arm by relative movement in the optical axis direction, the opening / closing blade 110b is opened / closed to open / close the optical path of the lens barrier unit 110.

  2 to 4, the first group ring 10 is provided with a decorative ring 112 for adjusting the appearance of the lens barrel 1. The decorative ring 112 has the same function as the decorative ring 102 for the straight ring 14 and is attached to the first group ring 10 and fixed integrally therewith. As a material for the decorative ring 112 and the decorative ring 102, for example, a metal such as an aluminum alloy or stainless steel is suitable, but it is needless to say that an engineering plastic can be used. The material of the first group ring 10, the first group lens frame 11, the second group ring 12, the rectilinear ring 14, the cam ring 15, the fixed ring 16, the third group lens frame 17 and the rear barrel 18 is, for example, fiber reinforced plastic. (FRP) is preferable, but it is possible to use ABS (acrylonitrile butadiene styrene resin) and other engineering plastics, as well as aluminum alloys and other metals.

  As shown in FIGS. 3 and 4, a flexible wiring board 115 is electrically connected to the automatic exposure apparatus 3. One end of the flexible wiring board 115 is connected to a wiring circuit of an actuator that drives a shutter mechanism, a variable aperture mechanism, and the like of the automatic exposure apparatus 3, and the other end is a power source installed outside the lens barrel 1. Electrically connected. One end of the flexible wiring board 115 is swung into the second group ring 12 with an appropriate slack so that no adverse effect is caused by its own reaction force even if the distance between the automatic exposure device 3 and the second group ring 12 changes. Yes.

  As described above, the automatic exposure apparatus 3 incorporated in the second group ring 12 starts to be pressed by the first group ring 10 from before the non-photographing state, and the interval between the second group ring 12 and the automatic exposure apparatus 3 is minimum in the non-photographing state. The outer cam groove 65 of the cam ring 15 is configured so that Thereby, in a non-photographing state, it is possible to realize a retractable lens barrel that is thinner than a conventional lens barrel.

  19A, B, 20A, B, 21A, B, C, 22A, B, C, 23A, B, 24, 25, 26A, B, 27A, B and 28A, B are FIG. 6 is a diagram for explaining a form in which the lens barrel 1 is extended from the lens barrel storage state and changed to a zooming state. Next, a variation of the lens barrel 1 will be briefly described.

  19A and 19B and FIGS. 20A and 20B show that the lens barrel 1 is in the lens barrel storage state. In this state, the three cam pins 98 of the first group ring 10 are located outside the cam groove opening 71 opened on the flange portion 15 b side in the lens barrel storage operation region 66 of the outer cam groove 65 of the cam ring 15. It is stored in the provided holding portion 73. At this time, of the three cam pins 98, the two cam pins 98 are located at the two notches 55a and 55b of the flange portion 15b. On the other hand, the remaining one cam pin 98 is inserted into a through hole 62 provided in the first flange portion 54a, and is exposed on the back side of the flange portion 15b as shown in FIGS.

  The forward / backward movement of the first group ring 10 is executed by the cam ring 15 being driven to rotate relative to the first group ring 10 based on the rotation of the drive gear 22 by the reduction gear unit 21. First, the feeding operation of the first group ring 10 will be described. When the cam ring 15 is rotated in the feeding direction, first, the cam ring 15 changes to a state as shown in FIGS. At this time, the pressing portion 72 provided on the cam ring 15 comes into contact with the inclined operation surface 99 of the bracket 10d provided on the first group ring 10, and the pressing portion 72 presses the operation surface 99 in the circumferential direction. At this time, due to the action of the inclined surface of the pressing portion 72 and the inclined surface of the operation surface 99, a force in the optical axis direction is generated on the operation surface 99.

  The cam pin 98 is changed from the state shown in FIGS. 21A, 21B, and 21C to the state shown in FIGS. That is, the contact between the pressing portion 72 and the operation surface 99 gradually transitions from the distal end of the bracket 10d to the proximal end side. When the cam pin 98 completely enters the outer cam groove 65, one of the cam pin 98 and the outer cam groove 65 is brought into contact with the pressing portion 72 and the operation surface 99 as shown in FIGS. It changes to abutment with the side surface. Thereafter, the cam pin 98 is guided to the outer cam groove 65 by the contact between the cam pin 98 and the outer cam groove 65, and the optical zooming operation shown in FIGS. 25, 26A, B, 27A, B and 28A, 28B is executed. Is done.

  25, 26A, and 26B show a state in which the lens barrel 1 has shifted from the lens barrel storage operation region 66 to the zooming operation region 67. FIG. When transitioning from this state to the state shown in FIGS. 27A and 27B, since the first lens group 2 changes in a direction approaching the second lens group 4, the wide (wide angle) side is strengthened. On the other hand, when the state shown in FIGS. 27A and 27B is changed to the state shown in FIGS. 28A and 28B, since the first lens group 2 changes in a direction away from the second lens group 4, tele (telephoto) ) Side is strengthened.

  The storing operation of the first group ring 10 is performed by the operation to the opposite side of the operations shown in FIGS. 19A and 19A to 28A and 28B.

  29A, B, FIGS. 30A, B and FIGS. 31A, 31B are views for explaining the positional relationship by cam engagement between the cam pin group 84 of the second group ring 12 and the inner cam groove group 74 of the cam ring 15. FIG. 29A is a cam development view of the lens barrel storage state in which the second group ring 12 and the cam ring 15 are both completely stored in the fixed ring 16. FIG. 29B is a cam development view in a state where the lens is moved from the lens barrel storage state to the optical zoom wide position. FIG. 30A is a cam development view in a state where the optical zooming is moved from the wide position to the neutral position. FIG. 30B is a cam development view in a state where the optical zooming is moved from the neutral position to the tele position.

  According to this embodiment, the front inner circumferential cam groove 75 extends over the entire length of the cam ring 15 in the optical axis direction, and cam groove openings 78 and 78 are provided at both the front end and the rear end of the cam ring 15. Thus, the stroke in the optical axis direction of the second group ring 12 can be set to the maximum. This point will be described in detail as follows. FIG. 31A is a schematic explanatory view showing a cross-section of the main part of the lens barrel 1 in the state of FIG. 29B. As shown in FIG. 31A, the ring portion 80 a of the rotation restricting member 80 is provided with a convex portion 120 that protrudes inward in the radial direction, and this convex portion 120 is configured to contact the stopper portion 121 of the second group ring 12. Yes.

  As described above, the convex portion 120 provided on the rotation regulating member 80 abuts against the stopper portion 121 of the second group ring 12, so that the second group ring 12 can be reliably prevented from falling off. As a result, the side wall portion E of the cam groove of FIG. 39C described as the prior art can be eliminated, and the cam groove can be lengthened in the optical axis direction accordingly. In this case, as shown in FIG. 29B, the front cam pin 85 of the second group ring 12 is located in the cam groove opening 78 at the rear end of the front inner peripheral cam groove 75, but the front cam pin 85 is the rotation restricting member 80. Therefore, the protrusion 120 restricts the separation from the front inner peripheral cam groove 75.

  Therefore, the front cam pin 85 is not detached from the front inner peripheral cam groove 75, and the same state as the cam engagement state can be maintained. Therefore, after that, the cam ring 15 can be smoothly returned to the engagement state with the front inner peripheral cam groove 75 again by further rotating the cam ring 15. Thus, in this embodiment, the optical axis of the front inner peripheral cam groove 75 is only the side wall portion E (strictly, the length of the side wall portion E and the radius of the front cam pin 85) shown in FIG. 39C. The length in the direction can be ensured, whereby the stroke of the second group ring 12 in the optical axis direction can be increased.

  FIG. 31B shows an example of an embodiment in which the front end of the second group ring 12 is received at the rear end of the first group ring 10 to prevent the second group ring 12 from falling off. In this case, the movement of the first group ring 10 in the optical axis direction with respect to the cam ring 15 is restricted within the range of the cam rotation angle that restricts the dropout of the second group ring 12.

  A digital still camera 300 shown in FIGS. 32 to 34 shows a first embodiment of an imaging apparatus configured using the lens barrel 1 of the present invention described above. The digital still camera 300 uses a semiconductor recording medium as an information recording medium, converts an optical image from a subject into an electrical signal by a CCD (solid-state imaging device), and records the signal on the semiconductor recording medium. It can be displayed on a flat display panel 302 which is a display device such as a liquid crystal display.

  This digital still camera 300 is a camera case in which the lens barrel 1 that takes an image of a subject as light and guides it to a CCD (imaging device) as an imaging means, and the lens barrel 1 and other devices and devices are incorporated. 301, a flat display panel 302 that is a display device including a liquid crystal display that displays an image based on a video signal output from the CCD, and a control that controls the operation of the lens barrel 1, the display of the flat display panel 302, and the like. The apparatus includes a device and a battery power source (not shown).

  The camera case 301 is formed of a horizontally long flat container, and includes a front case 303 and a rear case 304 that are overlapped in the front-rear direction, and a substantially rectangular frame interposed between the front case 303 and the rear case 304. The center case 305 and the like. A ring-shaped decorative ring 306 is attached to the front surface of the front case 303 at a position slightly deviated to one side from the center, and 1 on the front side of the lens barrel 1 is attached to the central hole 307 of the decorative ring 306. The group ring 10 and the like are facing advancing and retreating.

  FIG. 32 shows a non-photographing state (lens barrel storage state) of the lens barrel 1 corresponding to FIG. 1A, and the entire front surface of the lens barrel 1 is substantially flush with the front surface of the front case 303. It is configured as follows. FIG. 33 shows the photographing state (the extended state) of the lens barrel 1 corresponding to FIG. 1B. The decorative ring 112 that encloses the first group ring 10 and the decorative ring 102 that encloses the straight ring 14 are nested. It has been paid out.

  A light emitting unit 307 of a flash device and a light emitting / receiving unit 308 of an autofocus mechanism are provided at an oblique upper portion of the lens barrel 1 of the front case 303. Further, on the upper surface of the center case 305, a power button 309, a shutter button 310, a sound collecting hole 311 of a sound collecting device such as a microphone, and the like are provided. In addition, a battery storage portion in which a battery as a power source is detachably stored is provided on one side surface portion of the center case 305, and a battery lid 312 is detachably engaged with the battery storage portion. Yes. A speaker hole 313 for the speaker device is provided on the side surface of the center case 305 opposite to the battery lid 312.

  A display window 315 is greatly opened in the rear case 304, and the flat display panel 302 is attached to the display window 315. The flat display panel 302 has a touch operation function that can be operated by a user touching the display surface. Various operation switches are provided on one side of the flat display panel 302 of the rear case 304. As operation switches, for example, a mode switching switch 316 for selecting a function mode (still image, moving image, reproduction, etc.), an optical zoom operation button 317 for executing a zoom operation, a menu button 318 for selecting various menus, and a screen display are switched. The display switching button 319 and the like can be mentioned, but other direction keys for moving a cursor for selecting a menu, a screen button for switching a screen size, and deleting a screen can also be provided.

  A control device that drives and controls the lens barrel 1, the flat display panel 302, and the like is built in the camera case 301 having such a configuration. The control device is configured, for example, by mounting a predetermined microcomputer, a resistor, a capacitor, or other electronic components on a wiring board.

  FIG. 35 is a block diagram showing a first example of a schematic configuration of a digital still camera 300 including the lens barrel 1 having the configuration and operation as described above. The digital still camera 300 includes a lens barrel 1, a video recording / reproducing circuit unit 330 that plays a central role of a control device, a program memory, a data memory, and the like for driving the video recording / reproducing circuit unit 330. A built-in memory 331 having a RAM, a ROM, and the like, a video signal processing unit 332 that processes captured video and the like into a predetermined signal, a flat display panel 302 that displays the captured video and the like, and an external that expands the storage capacity A memory 333, a lens barrel control unit 334 that drives and controls the lens barrel 1, and the like are provided.

  The video recording / reproducing circuit unit 330 includes, for example, an arithmetic circuit having a microcomputer (CPU). A built-in memory 331, a video signal processing unit 332, a lens barrel control unit 334, a monitor driving unit 335, an amplifier 336, and two interfaces (I / F) 337 and 338 are connected to the video recording / reproducing circuit unit 330. Yes. The video signal processing unit 332 is connected to the CCD 7 attached to the lens barrel 1 via an amplifier 336. A signal processed into a predetermined video signal by the video signal processing unit 332 is input to the video recording / reproducing circuit unit 330.

  The flat display panel 302 is connected to the video recording / reproducing circuit unit 330 via the monitor driving unit 335. A connector 339 is connected to the first interface (I / F) 337, and an external memory 333 can be detachably connected to the connector 339. Further, a connection terminal 340 provided in the camera case 301 is connected to the second interface (I / F) 338. The lens barrel control unit 334 is connected to a lens driving unit 341 that drives and controls the lens barrel 1 and a position sensor 342 that detects a rotation amount of the lens barrel 1 and a movement amount in the optical axis direction. ing.

  Thus, when an image of the subject is input to the lens system of the lens barrel 1 and formed on the imaging surface of the CCD 7, the image signal is input to the video signal processing unit 332 via the amplifier 336. A signal processed by the video signal processing unit 332 into a predetermined video signal is input to the video recording / reproducing circuit unit 330. Accordingly, a signal corresponding to the subject image is output from the video recording / reproducing circuit unit 330 to the monitor driving unit 335, the built-in memory 331, or the external memory 333. As a result, an image corresponding to the image of the subject is displayed on the flat display panel 302 via the monitor driving unit 335, or is recorded as an information signal in the built-in memory 331 or the external memory 333 as necessary.

  The digital still camera 300 having such a configuration can be used as follows, for example. FIG. 32 shows a state where the open / close spring 10b of the lens barrier unit 110 in the lens barrel 1 is closed and the optical lens system is closed, that is, a non-photographing state. In this case, the power of the digital still camera 300 is turned off. FIG. 33 shows a state where the open / close spring 10b of the lens barrier unit 110 is opened and the optical lens system is opened, that is, a state where photographing is possible. This photographing enabled state is automatically executed by operating the power button 309 to turn on the power. As a result, the digital still camera 300 changes from the form shown in FIG. 32 to the form shown in FIG.

  When the digital still camera 300 is ready to shoot, the photographic lens is pointed at the subject and the shutter button 310 is pressed, so that the subject can be photographed and the image can be captured. At this time, by operating the optical zoom operation button 317, the focal length is continuously changed according to the operation direction without changing the position of the image point, and the wide (wide angle) screen or the tele (telephoto) screen. Can be obtained.

  As described above, according to the present invention, in a lens barrel having a cam ring having an outer peripheral gear train, the length of the cam groove in the optical axis direction can be increased without increasing the total length of the cam ring in the optical axis direction. The thickness can be increased. Therefore, by not changing the length of the cam groove in the optical axis direction, the total length of the cam ring in the optical axis direction can be reduced, and thus the entire lens barrel can be reduced in size. In the above-described embodiment, an example in which a lens is used as an optical element has been described. However, the optical element is not limited to this embodiment. For example, an optical filter, a prism, or other optical element is used. Of course you can.

  The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, an example in which a digital still camera is applied as the imaging device has been described. However, the present invention can also be applied to a digital video camera, a personal computer with a camera, a mobile phone with a camera, and other imaging devices. Furthermore, although the example using the third group lens as the optical lens has been described, it is needless to say that it may be the second group lens or less or the fourth group lens or more.

1A and 1B show a first embodiment of a lens barrel cam mechanism according to the present invention, in which FIG. 1A is a perspective view of a lens barrel in a retracted state, and FIG. It is. It is the perspective view which decomposed | disassembled the lens-barrel shown in FIG. FIG. 2 is a cross-sectional view of the lens barrel shown in FIG. It is sectional drawing of the lens barrel extension state of the lens barrel shown in FIG. FIG. 2 is a perspective view of a stationary ring according to the lens barrel shown in FIG. 1. FIG. 6 is a development view in which the fixed ring shown in FIG. 1 shows a cam ring according to the lens barrel of FIG. 1, in which FIG. A is a perspective view, FIG. B is a front view, and FIG. C is a cross-sectional view taken along line XX in FIG. The cam ring of FIG. 7 is shown, The same figure A is a top view, The same figure B is a bottom view. FIG. 7 is a developed view showing the cam ring of FIG. 7. FIG. 7A is a developed view showing the cam groove on the outer peripheral surface, and FIG. 7B is a developed view showing the cam groove on the inner peripheral surface with a broken line. FIG. 3 is a development view in which a rotation regulating member of the lens barrel shown in FIG. 2 is developed. FIG. 3 is a development view in which a rectilinear ring of the lens barrel shown in FIG. 2 is developed and guide grooves on an inner peripheral surface are represented by broken lines. It is the perspective view which decomposed | disassembled and expressed the automatic exposure apparatus of the lens-barrel shown in FIG. 2, an interval control member, and 2 group ring. FIG. 3 is a development view in which a second group ring of the lens barrel shown in FIG. 2 is developed. FIG. 3 is an exploded perspective view showing a first group ring and a first group lens frame of the lens barrel shown in FIG. 2. FIG. 15 is a development view in which the first group lens frame shown in FIG. FIG. 2A is a perspective view of the lens barrel shown in FIG. 2 in combination with the first group ring and the cam ring, and FIG. FIG. 16 is a diagram for explaining the relationship between the assembly of the first group ring and the cam ring shown in FIG. 16 and the drive gear, where FIG. A is a front view and FIG. B is a bottom view. 16A and 16B are diagrams for explaining the relationship between the assembly of the first group ring and the cam ring shown in FIG. 16 and the drive gear, where FIG. A is a right side view, and FIG. B is a cross-sectional view taken along line YY in FIG. FIG. 17 explains the relationship between the assembly of the first group ring and cam ring shown in FIG. 17 and the drive gear. FIG. A shows that the cam follower of the first group ring moves completely out of the cam groove opening of the cam ring. The perspective view and B of the figure are half sectional views. FIG. 19 explains the relationship between the assembly of the first group ring and the cam ring shown in FIG. 19 and the drive gear. FIG. A is a developed view showing the main part by developing the first group ring and the cam ring, and FIG. FIG. 4 is a developed view showing a cam groove opening by partially cutting the gear portion of FIG. FIG. 17 explains the relationship between the assembly of the first group ring and the cam ring shown in FIG. 17 and the drive gear. FIG. A is a perspective view of the cam follower of the first group ring moved to the cam groove opening of the cam ring. FIG. 3B is a half sectional view, and FIG. 3C is a development view in which the first group ring and the cam ring are developed, and a part of the gear portion is sectioned to show the cam groove opening. FIG. 17 explains the relationship between the assembly of the first group ring and cam ring shown in FIG. 17 and the drive gear. In FIG. A, the cam follower of the first group ring moves from the cam groove opening of the cam ring into the cam groove. B is a half sectional view, and FIG. C is a developed view showing a cam groove opening by developing a first group ring and a cam ring and a section of a gear part. FIG. 17 explains the relationship between the assembly of the first group ring and cam ring shown in FIG. 17 and the drive gear. In FIG. A, the cam follower of the first group ring moves from the cam groove opening of the cam ring into the cam groove. The perspective view and B of the figure are half sectional views. FIG. 18 is a diagram for explaining the relationship between the assembly of the first group ring and cam ring shown in FIG. 17 and the drive gear, in which the first group ring and cam ring shown in FIG. It is a development view showing an opening. FIG. 17 is a perspective view illustrating a relationship between the assembly of the first group ring and cam ring and the drive gear shown in FIG. It is. FIG. 17 explains the relationship between the assembly of the first group ring and cam ring shown in FIG. 17 and the drive gear, in which FIG. A is a half sectional view, and FIG. FIG. 5 is a developed view showing a cam groove opening by sectioning a part of the gear portion. FIG. 17 explains the relationship between the assembly of the first group ring and the cam ring shown in FIG. 17 and the drive gear. FIG. FIG. 7B is a development view in which the first group ring and the cam ring of FIG. A are developed, and a part of the gear portion is sectioned to show the cam groove opening. FIG. 17 explains the relationship between the assembly of the first group ring and the cam ring shown in FIG. 17 and the drive gear, and FIG. FIG. 7B is a development view in which the first group ring and the cam ring of FIG. A are developed, and a part of the gear portion is sectioned to show the cam groove opening. 12A and 12B illustrate the cam engagement relationship between the second group ring and the cam ring shown in FIG. 12, in which FIG. A is a cam development view in a lens barrel storage state, and FIG. 12B is a cam development view in a zooming wide state. FIGS. 12A and 12B are diagrams for explaining the cam engagement relationship between the second group ring and the cam ring shown in FIG. 12. FIG. A is a cam development view in a zooming / neutral state, and FIG. FIG. 12 is a cross-sectional view of the cam engagement state of the second group ring and the cam ring shown in FIG. 12, and FIG. A is an explanatory view in which the second group ring is prevented from falling off by a rotation restricting member attached to the cam ring. These are explanatory drawings which prevented the dropout of the second group ring in the first group ring. FIG. 2 is a perspective view of a digital still camera showing an example of an imaging apparatus using the lens barrel of FIG. 1 as seen from the front side in a lens barrel storage state. FIG. 2 is a perspective view showing a digital still camera showing an embodiment of an imaging apparatus using the lens barrel of FIG. 1 as seen from the front side in a lens barrel extended state. FIG. 2 is a perspective view of a digital still camera showing an example of an imaging apparatus using the lens barrel of FIG. 1 as viewed from the back side. It is block explanatory drawing showing the schematic structure of the digital still camera which shows the implementation example of the imaging device using the lens-barrel of FIG. FIG. 2A shows a schematic configuration of a conventional lens barrel. FIG. 1A shows a state in which the front cam pin is detached from the cam groove, and FIG. 2B shows that both the front cam pin and the rear cam pin are engaged with the cam groove. FIG. 3C is an explanatory diagram showing the state where the rear cam pin is detached from the cam groove. It is a cam development view showing the positional relationship between the cam pins of the second group ring and the cam grooves of the cam ring in the conventional lens barrel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens barrel, 2 ... 1st lens group, 3 ... Automatic exposure apparatus, 4 ... 2nd lens group, 5 ... 3rd lens group, 7 ... Image pick-up element (CCD), 10 ... 1 group ring (straight advance member) 11 ... 1 group lens frame, 12 ... 2 group ring (straight forward member), 13 ... 2 group lens frame (inner flange part), 14 ... straight forward ring, 15 ... cam ring (rotating member), 16 ... fixed ring, 17 ... 3 group lens frame, 18 ... Rear barrel, 20 ... CCD unit, 21 ... Reduction gear unit, 22 ... Drive gear, 23 ... F motor unit, 37A, 37B, 37C ... Cam groove, 38A, 38B, 38C ... Straight guide groove, 57A, 57B, 57C ... cam projection, 60 ... gear portion, 62 ... through hole, 65 ... outer cam groove (cam groove), 66 ... lens barrel storage operation region, 67 ... zooming operation region, 71 ... Cam groove opening, 72 ... Pressing portion, 73 ... Hold 74 ... Inner cam groove group, 75 ... Front inner peripheral cam groove, 76 ... Rear inner peripheral cam groove, 80 ... Rotation restricting member, 83 ... Straight guide groove, 84 ... Cam pin, 85 ... Front cam pin, 86 ... Rear cam pin, 89 ... Guide protrusions, 94 ... Interval restriction members, 97 ... Guide convex portions, 98 ... Cam pins (cam followers), 101 ... Linear guide grooves, 110 ... Lens barrier units, 110b ... Opening / closing blades, 120 ... Protrusions, 121 ... Stopper unit 300 ... Digital still camera (imaging device) 301 ... Camera case 302 ... Plane display panel (display device) 309 ... Power button 310 ... Shutter button 334 ... Lens barrel control unit

Claims (4)

A rectilinear member that holds the optical element and is movable in the optical axis direction of the optical element and provided with a cam follower;
Provided on the peripheral surface is a cam groove that is rotatable relative to the rectilinear member and is also movable relative to the optical axis direction and is slidably engaged with the cam follower. A rotating member,
In the cam mechanism of the lens barrel in which the cam follower is guided by the cam groove by rotating the rotating member to move the rectilinear member forward and backward in the optical axis direction.
The cam groove is formed with a plurality of cam grooves having the same cam curve with at least different positions in the optical axis direction, and at least one cam groove of the plurality of cam grooves is the rotating member. The first cam groove opening and the second cam groove opening are provided at both end faces in the optical axis direction of the first cam groove, and the remaining cam grooves of the plurality of cam grooves are the light of the rotating member. A third cam groove opening is provided on one end surface or the other end surface in the axial direction,
The cam follower comprises a plurality of cam followers that are slidably engaged with the plurality of cam grooves, respectively.
Disengagement limiting means is provided for maintaining a state in which at least one of the plurality of cam followers is engaged with any of the plurality of cam grooves, or for restricting the cam follower from separating from the cam grooves. A lens barrel cam mechanism.   The detachment restricting means is a convex portion protruding from a peripheral surface of the rotating member where the cam groove is provided, and the convex portion restricts movement of the rectilinear member in the optical axis direction. The lens barrel cam mechanism according to claim 1.   The detachment restricting means is a rectilinear movement restricting portion provided on a rotation restricting member that restricts movement in the optical axis direction with respect to the turning member and is capable of only relative turning. The lens barrel cam mechanism according to claim 1.   The detachment restricting means is a rectilinear movement restricting portion provided on a rotation restricting member that restricts relative rotation with respect to the rectilinear member and is movable only in the optical axis direction. Item 10. A lens barrel cam mechanism according to Item 1.

Images