JP2010250175A - Zoom lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens barrel capable of shortening length in the direction of lens optical axis in a non-imaging state being a barrel sunk state. <P>SOLUTION: This extensible and contractible zoom lens barrel 1 includes a first group frame 2 provided with a cam follower 51 and a cam follower 52, a second group zoom frame 6, a second group frame 8 supported turnably in the second group zoom frame 6 and being able to evacuate, a cam groove 12c engaging and coming into slide-contact with the cam follower 51, cam grooves 12e, 12f for letting the second group frame 8 evacuate, a thin-walled through-part 12c5 arranged on a rear surface of an escape part 12h for moving and letting the second group frame 8 evacuate and being a part of the cam groove 12c, and a cam frame 12 having the same cam stripe as that of the through-part and having a cam groove 12d coming into slide-contact with the cam follower 52, when the cam follower 51 is positioned in the through-part. While this zoom lens barrel is in a zoom state between a wide angle end and a telephotographic end, the shock force acting on the first group frame 2 is received by the through-part 12c5 and the cam groove 12d. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a zoom lens barrel to which a lens frame advancing / retracting mechanism including a cam follower and a cam groove is applied.

  2. Description of the Related Art Conventionally, in a zoom lens barrel to which a lens frame advancing / retracting mechanism including a cam follower and a cam groove is applied, one disclosed in Patent Document 1 includes two cam pins for driving a single lens holding frame forward and backward. Two rows of cam grooves are provided along the circumferential direction as cam grooves to be engaged with the (cam follower), and one of the two rows of cam grooves is fitted with no gap to the cam pin. The other cam groove is a cam groove in an engaged state with a gap. The lens holding frame is positioned by the one cam groove and is driven forward and backward. When an impact force is applied, the other cam groove abuts on the other cam pin. Therefore, the cam pin can be prevented from dropping out of the cam groove and the cam pin being bitten into the cam groove, and the dimensional accuracy of the cam groove can be ensured and the size and weight can be easily reduced and the manufacturing cost can be reduced. be able to.

Japanese Patent No. 3811281

  However, in the lens barrel disclosed in Patent Document 1, it is necessary to provide the cam frame with two rows of cam grooves over the entire driving range, and therefore the length of the cam frame in the lens optical axis direction increases. . Accordingly, the length of the lens barrel in the direction of the optical axis of the lens increases, which hinders the compactness and thinning of the camera to which the lens barrel is mounted.

  The present invention has been made to solve the above-described problems, and can be shortened in the lens optical axis direction in a non-shooting state that is a retracted state, and the camera to which the lens barrel is attached can be made thinner. An object is to provide a realizable zoom lens barrel.

  In order to solve the above problems, a zoom lens barrel according to the present invention is a zoom lens barrel that is extendable and retractable, and includes a first cam follower and a third cam follower, and is a zoom optical system that constitutes a zoom lens. A first moving frame having a lens and another zoom lens of the zoom optical system are held, and during zoom operation when photographing is possible, the zoom optical system is operated in accordance with the expansion / contraction operation of the zoom lens barrel. Supports a retraction frame that retreats from the optical axis in conjunction with the shortening operation of the zoom lens barrel during non-shooting when the zoom lens barrel is moved shorter than when the image can be taken and moves on the optical axis. A second moving frame provided with a second cam follower, and a circumferential wall provided on the circumferential wall for moving the first moving frame in the optical axis direction, wherein the second moving frame rotates about the optical axis and engages with the first cam follower. Mating A bottomed first cam groove, a second cam groove engaged with and slidably engaged with the second cam follower for retracting the retracting frame to the outside of the optical axis in conjunction with the shortening operation, and the retracting frame In the retracted state, a thinned portion where the circumferential wall is thinned for the retracting operation of the retracting frame, and a part of the first cam groove disposed on the back surface of the thinned portion, The penetrating portion that penetrates the thin portion and the same cam streak as the first cam groove are provided in parallel to the penetrating portion and the optical axis direction, and at least the first cam follower is positioned at the penetrating portion. A third cam groove having a sliding contact with the third cam follower and a cam frame having the third cam groove.

  According to the zoom lens barrel of the present invention, it is possible to shorten the lens optical axis direction in a non-photographing state that is a retracted state, and to realize a thin camera for mounting the lens barrel. A tube can be provided.

1 is an exploded perspective view of a zoom lens barrel that is an embodiment of the present invention. 1 is a longitudinal sectional view including the optical axis of the photographing lens in the retracted state of the zoom lens barrel of FIG. 1 is a longitudinal sectional view including the optical axis of the photographing lens in the wide / tele intermediate state where the zoom lens barrel of FIG. 1 can be photographed. An enlarged perspective view of a cam frame applied to the zoom lens barrel of FIG. An enlarged side view of a cam frame applied to the zoom lens barrel of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A zoom lens barrel according to an embodiment of the present invention will be described with reference to FIGS. In the following description, the optical axis of the photographic lens of the present lens barrel is “O”, and in the optical axis O direction, the subject side is the front (the feeding side of each lens frame), and the imaging side is the rear (the each lens frame is (Retract side). Moreover, the rotation direction of each member is shown by the rotation direction seen from the front side.

  The zoom lens barrel 1 of the present embodiment incorporates an image pickup unit 22 for converting a subject image into an electric signal, and the movable lens frame member projects forward in the optical axis O direction and the optical axis. It is a zoom lens barrel that can be extended and retracted to a retracted state that is a non-photographing state and is housed rearward in the O direction.

  Specifically, the zoom lens barrel 1 of the present embodiment is mainly supported by the fixed frame 17 and the fixed frame 17 as shown in FIGS. 1 to 3, and the rotary frame 14 is driven to rotate forward and backward during zooming and retracting driving. A moving frame 15 that advances and retreats together with the rotating frame 14 in the rotation restricted state, a cam frame 12 that rotates together with the rotating frame 14 and moves forward and backward, and a second group linear guide frame 13 that moves forward and backward together with the cam frame 12 in the rotation restricted state The first-group linear guide frame 5 that moves forward and backward together with the cam frame 12 in a rotation-restricted state, and the shutter unit 7 and the second-group frame 8 that is a retracting frame are swingably supported by the cam frame 12 in a rotation-restricted state. A second group zoom frame 6 as a second moving frame, a first group frame 2 as a first moving frame that is driven forward / backward by a cam frame 12 in a rotation-restricted state, and a forward / backward driving during focusing or retracting driving An imaging base plate 18 that holds the group frame 16, the fourth group frame 41, and the imaging unit 22 and is supported by the fixed frame 21, and a group lens 31 as a zoom lens that is held in the group frame 2 as a photographing optical system A second group lens 32 as a retractable zoom lens held in the second group frame 8, a third group lens 33 as a focusing lens held in the third group frame 16, and a fourth group held in the fourth group frame 41. A lens 34 and a zoom drive unit 19 and a focus drive unit 21 arranged on the fixed frame 17 are provided.

  The fixed frame 17 is a cylindrical member fixed to the camera body, and is a cam in which an inclined cam groove portion inclined with respect to the optical axis O and a circumferential cam groove portion along the circumference are connected to the inner peripheral portion. A groove 17a, a rectilinear groove 17b along the optical axis O, and a recess 17c that accommodates the long gear 56 are provided. Further, a unit for performing zooming driving of the photographing lens on the outer side of the cylinder, including a zoom motor and a gear train for driving the long gear 56, and a unit for performing focusing driving of the photographing lens A focus drive unit 21 including a focus motor, a gear train, a feed screw and a guide shaft is incorporated. The long gear 56 is accommodated in the concave portion 17c and is rotatably supported in a state where it is exposed to the inner peripheral portion of the fixed frame 17 along a direction parallel to the optical axis O.

  The rotating frame 14 is a cylindrical member that is fitted into the inner peripheral portion of the fixed frame 17 so as to be capable of rotating and retreating. A cam follower 14b and a gear portion 14a that can be engaged with the long gear 56 are provided on the outer peripheral rear portion. In the inner peripheral portion, a protrusion 14c is provided at the front position, a circumferential groove 14d along the circumferential direction is provided at an intermediate position in the optical axis O direction, and a cam frame straight advance groove 14e along the optical axis O direction.

  The rotating frame 14 has a cam follower 14b slidably fitted in the cam groove 17a of the fixed frame 17, and is driven to rotate by the long gear 56 via the gear portion 14a. Then, it is extended to a wide position, and then rotated to the tele position without moving back and forth in the direction of the optical axis O. The long gear 56 is rotationally driven via a gear train (not shown) of a zoom drive unit 19 including a zoom motor disposed on the fixed frame 17.

  The moving frame 15 is a cylindrical member that is fitted into the inner peripheral portion of the rotating frame 14 so as to be relatively rotatable, and includes a guide protrusion 15a at the rear end outer peripheral portion, a circumferential groove 15b at the outer peripheral front portion, and an outer peripheral central portion. Are provided with a cam frame cam groove 15e inclined with respect to the optical axis O direction and a linearly moving first and second group linear guide frame rectilinear groove 15d as grooves extending through the inner and outer peripheries. It has been.

  The moving frame 15 is inserted into the inner peripheral portion of the rotating frame 14 with the guide protruding portion 15a slidably inserted into the rectilinear groove 17b of the fixed frame 17, and the protruding portion 14c is inserted into the inner peripheral portion of the rotating frame 14. Is inserted into the circumferential groove 15b, and the protrusion 15c is further inserted into the circumferential groove 14d. Therefore, the moving frame 15 is supported in a state in which the moving frame 15 can be relatively rotated with respect to the rotating frame 14 in a state where the rotation is restricted by the fixed frame 17, and moves integrally in the optical axis O direction.

  The cam frame 12 is a cylindrical member that fits into the inner peripheral portion of the moving frame 15, and the cam frame 12 has three cam followers 55 projecting outward from the outer peripheral rear portion of the cam frame 12, and a portion at a front position in the vicinity of the cam follower 55. A circumferential guide groove 12a, a bottomed first cam groove 12c including a cam groove portion which is an outer peripheral cam groove and does not have a bottom portion, and a third cam groove 12d are provided. Further, three pairs of cam grooves, that is, second cam grooves 12e and 12f and a protrusion 12b are provided on the inner peripheral portion.

  As shown in FIGS. 3 and 4, the cam follower 55 includes a conical cam follower portion 55b and a tip cylindrical portion 55a.

  The cam groove 12c and the cam groove 12d form a pair of cam grooves and engage with the pair of cam followers 51 and 52 of the first group frame 2, and the paired cam grooves 12e and 12f are a pair of the two group zoom frame 6. The cam followers 53 and 54 are engaged with each other. The detailed shape and operation thereof will be described later.

  The cam frame 12 is inserted into the inner peripheral portion of the moving frame 15, passes through the conical cam follower portion 55 b of the cam follower 55 in a state where the cam groove 15 e of the moving frame 15 is slidably engaged, and further the cam follower 55. The tip end cylindrical portion 55a is assembled in a state of being fitted into the rectilinear groove 14e of the rotary frame 14. Therefore, the cam frame 12 rotates together with the rotating frame 14 and is relatively advanced and retracted by the cam groove 15 e of the moving frame 15.

  The second group linear guide frame 13 is a ring-shaped member, and includes a protrusion 13a protruding to the outer periphery of the rear end, a circumferential groove 13b arranged along the outer periphery, and a straight movement protruding forward in the optical axis O direction. And a guide key 13c.

  The second group linear guide frame 13 is inserted into the inner peripheral portion of the moving frame 15, and the protrusion 13a is slidably fitted into the linear groove 15d of the moving frame 15, and the cam frame 12 is inserted into the circumferential groove 13b. The protrusion 12b is slidably fitted. Therefore, the second group straight guide frame 13 moves forward and backward in the direction of the optical axis O together with the cam frame 12 in a state in which the rotation is restricted via the moving frame 15.

  The straight guide frame 5 for the first group is a cylindrical member, and includes a protrusion 5a protruding to the outer periphery of the rear end, a circumferential protrusion 5b disposed along the rear end of the inner periphery, and an optical axis O direction of the inner periphery. And a rectilinear groove 5c.

  The one-group linear guide frame 5 is inserted into the inner peripheral portion of the moving frame 15 so that the protruding portion 5a is slidably fitted into the linear groove 15d of the moving frame 15, and the circumferential protruding portion 5b is inserted into the cam frame 12. The circumferential guide groove 12a is slidably fitted. Accordingly, the first group straight advance guide frame 5 moves forward and backward in the optical axis O direction together with the cam frame 12 in a state in which the rotation is restricted by the moving frame 15.

  The second group zoom frame 6 is a cylindrical member, and has a rectilinear groove 6a along the optical axis O direction on the outer periphery, cam followers 53 and 54 that are three pairs of second cam followers, and an optical axis O direction inside. And a side wall opening 6c are provided. The paired cam followers 53 and 54 are arranged along the direction of the optical axis O with a predetermined distance therebetween. A shutter unit 7 is inserted into the second group zoom frame 6 from the rear side, and a second group frame 8 is incorporated behind the shutter unit 7.

  The second group zoom frame 6 is fitted into the inner peripheral portion of the cam frame 12, and the cam followers 53 and 54 are engaged with the cam grooves 12 e and 12 f of the cam frame 12. Further, the rectilinear guide key 13c of the second group rectilinear guide frame 13 is slidably fitted into the rectilinear groove 6a and assembled. Therefore, the second group zoom frame 6 is restricted in rotation by the straight guide key 13c while holding the shutter unit 7 and the second group frame 8, and moves forward and backward in the direction of the optical axis O as the cam frame 12 rotates.

  The shutter unit 7 includes a shutter blade 35 for opening and closing the aperture opening 7a, and a two-group zoom frame is disposed in the shaft hole 7b along the optical axis O direction with an urging spring (not shown) interposed therebetween. Six guide shafts 6 b are fitted and attached to the second group zoom frame 6. Therefore, the shutter unit 7 is supported in a state of being separated from the second group zoom frame 6 in the direction of the optical axis O by a predetermined distance when the biasing spring is opened (the lens barrel 1 can be photographed) (FIG. 3). When the second group zoom frame 6 is retracted in the direction of the optical axis O in the retracted state of the lens barrel 1, the urging spring is compressed and approaches the second group zoom frame 6 so as to be in close contact (FIG. 2). ).

  The second group frame 8 is a member that holds the second group lens 32, and is a support shaft provided in the second group zoom frame 6 in parallel with the optical axis O that fits into the shaft hole portion 8 a with respect to the second group zoom frame 6. 9 is supported so as to be rotatable (swingable) on a surface orthogonal to the optical axis O. Further, a cam follower 8b is provided, and the cam follower 8b is pressed and rotated by a protruding retraction cam (not shown) provided on the fixed frame 17 or the imaging base plate 18.

  When the lens barrel 1 is in a photographing enabled state, the second group frame 8 is rotated clockwise about the support shaft 9 and the second group lens 32 is positioned on the optical axis O (FIG. 3). ). When the lens barrel 1 is retracted, the second group frame 8 is rotationally driven (swinged) counterclockwise around the support shaft 9 by the retraction cam provided on the fixed frame 17 side. The lens 32 is retreated from the optical axis O, and a part of the lens holding part of the second group frame 8 is retreated to a retreat position where a part protrudes from the side wall opening 6c of the second group zoom frame 6 (FIG. 2). Thus, in the retracted state, the second group lens 32 is retracted from the optical axis O, so that the first group frame 2 can be moved further back in the optical axis O direction.

  The first group frame 2 is a cylindrical member, and a first group lens 31 is held in the central opening, and a lens barrier 3 that can be opened and closed is arranged on the front side of the first group lens 31. Ring 4 is fixed. A rectilinear guide protrusion 2a along the optical axis O direction on the outer periphery of the group frame 2, and a cam follower that protrudes toward the inner periphery of the protrusion 2a, including three first cam followers 51 and one second A cam follower 52 is provided. The cam followers 51 and 52 that are paired only at one place are arranged at positions along the optical axis O direction at a predetermined distance.

  The first group frame 2 is fitted into the inner periphery of the first group straight advance guide frame 5, and the straight guide protrusion 2a is fitted into the straight advance groove 5c. Further, the first group frame 2 is fitted so as to cover the outer periphery of the cam frame 12, and is assembled by engaging the cam followers 51 and 52 with the cam grooves 12c and 12d. Accordingly, the first group frame 2 moves back and forth in the direction of the optical axis O as the cam frame 12 rotates and advances and retreats under a state in which the rotation is restricted by the first group linear guide frame 5.

  The third group frame 16 holds a third group lens 33, and is supported by the fixed frame 17 so as to be movable back and forth in the optical axis O direction. The third group frame 16 is disposed on the fixed frame 17 and includes a focus motor and a feed mechanism. It is driven forward and backward during focus drive and retracted drive via the.

  A fourth group frame 41 holding the fourth group lens 34 and the imaging unit 22 are attached to the front surface of the imaging base plate 18, and are positioned and fixed to the rear surface of the fixed frame 17. The imaging unit 22 includes an optical filter and an imaging device mounted on the connection FPC 43.

  Here, the detailed shapes of the three cam grooves 12c and one cam groove 12d on the outer peripheral part of the cam frame 12 and the three pairs of cam grooves 12e and 12f on the inner peripheral part are shown in FIGS. 5 will be described.

  The paired cam grooves 12c and 12d are formed in the same cam streak shape at the front and rear positions (the cam groove 12d side is disposed at the front position) translated in the optical axis O direction. The cam groove 12c engages with the cam follower 51 of the first group frame 2, and the cam groove 12d engages with the cam follower 52 of the first group frame 2. When the cam frame 12 is rotated from the retracted rotation position to the tele rotation position through the wide rotation position, the cam frame 12 has a cam line for moving the group frame 2 back and forth to each predetermined position.

  As shown in FIG. 4, the paired cam grooves 12c are a retracted position corresponding cam groove 12c1, a retracted / wide corresponding cam groove 12c12, a wide position corresponding cam groove 12c2, and a wide / telescopic cam groove 12c23. And a tele-position corresponding cam groove 12c3.

  The other cam groove 12d, which is a pair of cam grooves 12c, comprises a retracted position corresponding cam groove 12d1, a retracted / wide corresponding cam groove 12d12, and a wide / tele compatible cam groove 12d23.

  The cam groove portion 12c1 corresponding to the retracted position in the cam groove 12c has an open groove shape in which a cam wall portion on the rear side is cut. A part of the wide / telescopic cam groove 12c23 is located on the outer peripheral side of a relief portion 12h (described later) that forms a thin portion for retracting the second group frame on the inner peripheral portion of the cam frame 12. A part of the cylinder of the cam frame 12 has a small thickness, and a penetrating part 12c5 in which a part of the bottom of the cam is opened is formed (FIGS. 2 and 3). Further, the distal end portion of the tele-position corresponding cam groove portion 12c3 has an open shape.

  The thin relief portion 12h at the inner peripheral portion of the cam frame 12 will be described. When the lens barrel 1 is in the retracted state as shown in FIG. 2, the second group frame 8 is in the retracted rotation position as described above. When moved, the lens holding portion of the second group frame 8 protrudes outward from the side wall opening 6c of the second group zoom frame 6. In order to prevent the lens holding portion from coming into contact with the inner periphery of the cam frame 12 and insufficient retraction, a thin relief portion 12 h is provided on a part of the inner periphery of the cam frame 12. By providing the escape portion 12h, an increase in the outer diameter of the cam frame 12 is suppressed.

  Accordingly, a through portion 12c5 in which a part of the wide / telephoto corresponding cam groove portion 12c23 of the cam frame 12 has no bottom surface is formed. However, since the escape portion 12h is one place, a portion corresponding to the through portion 12c5 is not formed for the other two of the three cam grooves 12c.

  The cam groove 12d1 corresponding to the retracted position in the cam groove 12d is formed of a complete cam groove without a notch. Therefore, as described above, even if the rear cam wall surface of the retractable cam groove portion 12c1 to which the cam follower 51 is to be engaged is cut, the cam follower 52 is engaged with the retractable cam groove portion 12d1 having both wall surfaces. Thus, the first group frame 2 is securely held at the desired retracted position. As described above, the paired cam grooves 12d are not provided for the other two cam grooves 12c. However, the cam follower 51 that engages with the other two cam grooves 12c is in contact with the rear end flange surface of the second group rectilinear guide frame 13 in a state where the cam follower 51 is positioned in the retracted cam groove portion 12c1. Positioning in the rear direction of the optical axis O is performed, and the retracted position of the first group frame 2 is reliably maintained.

  Further, since the cam frame front end face is cut by the cam groove 12d, there is no wide position corresponding cam groove, a tele position corresponding cam groove, and a front wall surface portion of the wide / tele compatible cam groove. However, when the lens barrel is in the wide state and the vicinity thereof, or in the tele state and the vicinity thereof, the cam follower 51 of the group frame 2 has the cam groove portion 12c2 corresponding to the wide position of the cam groove 12c and the cam groove portion corresponding to the wide / tele. 12c23, to engage with the tele-position corresponding cam groove 12c3, the first group frame 2 moves forward and backward along a desired cam line.

  Further, the wide / telescopic cam groove portion 12d23 has no cam wall front wall surface because the cam frame front end surface is cut, but the cam groove rear wall surface is formed in a complete state. On the other hand, the rear wall surface side of the wide / telephone corresponding cam groove 12c23 in the through-hole 12c5 of the cam groove 12c is thin in the radial direction as described above. When the rearward impact force due to dropping or the like acts on the group frame 2 via the cam followers 52, 51, as described above, the rear-wall radial thickness of the wide / telescopic corresponding cam groove portion 12c23 in the through portion 12c5. Even if it is thin, the impact force can be received also on the rear wall surface of the wide / telescopic corresponding cam groove 12d23, so that the cam groove of the cam frame 12 can be prevented from being damaged. This also reduces the possibility of the followers 51 and 52 coming off the cam groove.

  The paired cam grooves 12e and 12f are formed in the same cam streak shape at the front and rear positions (the cam groove 12f side is disposed at the front position) translated in the optical axis O direction. The cam groove 12e is in sliding contact with the cam follower 53 of the second group zoom frame 6, and the cam groove 12f is in sliding contact with the cam follower 54 of the second group zoom frame 6. The cam frame 12 has cam lines that rotate from the retracted rotation position to the tele rotation position via the wide rotation position, and advance and retract the second group zoom frame 6 to and from each zoom position.

  As shown in FIG. 4, one cam groove 12e as a pair includes a retracted position corresponding cam groove 12e1, a wide / telescopic corresponding cam groove 12e23, and a tele position corresponding cam groove 12e3. The tele-position corresponding cam groove 12e3 is disposed on the front end protruding portion 12g of the cam frame 12.

  The other cam groove 12f in the pair includes a retracted position corresponding cam groove 12f1, a retracted / wide corresponding cam groove 12f12, a wide position corresponding cam groove 12f2, and a wide / tele compatible cam groove 12f23.

  In the cam groove 12e, there is no cam groove portion between the retracted position corresponding cam groove portion 12e1 and the wide / telephoto corresponding cam groove portion 12e23 because the cam frame rear end surface is cut. However, the retracted / wide cam groove 12f12 and the wide position cam groove 12f2 exist on the cam groove 12f side, and the cam follower 54 is engaged. Therefore, the second group zoom frame 6 advances and retreats along the desired cam line even between the retracted / wide and near the wide position.

  Further, since the cam frame front end surface is cut in the cam groove 12f, there is no tele-position corresponding cam groove. However, since the cam follower 53 is engaged with the tele position corresponding cam groove 12e3 on the cam groove 12e side, the second group zoom frame 6 is held at a desired tele corresponding position.

  Next, the advancing / retreating operation of the lens barrel 1 having the above-described configuration will be described with reference to FIGS.

  When the lens barrel 1 is set up from the retracted state shown in FIG. 2 to the photographable state shown in FIG. 3, when the rotary frame 14 is driven clockwise via the long gear 56 by the zoom drive unit 19, The fixed frame 17 is extended to a front position where photographing is possible. FIG. 3 shows an intermediate shooting state between the wide and telephoto of the lens barrel 1.

  The cam frame 12 is drawn forward of the rotating frame 14 by the cam groove 15 e of the moving frame 15. The first group frame 2 and the second group zoom frame 6 are extended forward in the optical axis O direction by the cam grooves 12c, 12d and 12e, 12f of the cam frame 12, respectively.

  Further, the shutter unit 7 is extended forward as the second group zoom frame 6 is extended. The second group frame 8 is also fed out together with the shutter unit 7, but in the initial stage of the feeding process, the second group frame 8 is driven to rotate clockwise around the support shaft 9, and the second group lens 32 enters the photographing optical path on the optical axis O. To do.

  The third group frame 16 is driven forward / backward by the focus drive unit 21 to a focusing position corresponding to the photographing state.

  When the lens barrel 1 is in a photographing state in a predetermined range between wide and telephoto as shown in FIG. 3, the cam follower 51 of the group frame 2 is formed in the through portion 12c5 of the wide / telescopic corresponding cam groove portion 12c23 of the cam frame 12. The cam follower 52 is engaged with the wide / telescopic corresponding cam groove 12d23. In this state, when an impact force in the direction of the optical axis O acts on the front surface portion of the first group frame 2, the impact force is applied to the rear end surface of the wide / television corresponding cam groove portion 12d23 having the through portion 12c5 through the cam follower. This is received by both rear end surfaces of the inter-telephone corresponding cam groove 12d23. This avoids breakage of the cam groove due to the impact force. Further, the possibility that the cam followers 51 and 52 are detached from the cam grooves 12c and 12d is reduced.

  When the lens barrel 1 is set down from the above-described shootable state to the retracted state, the zoom frame 19 further rotates the rotary frame 14 counterclockwise in the shootable state of FIG. By this rotational drive, the rotating frame 14 moves in the retracting direction while rotating.

  As the rotating frame 14 rotates and moves in the retracting direction, the cam frame 12 is also rotated while being retracted, and the first group frame 2 and the second group zoom frame 6 are driven in the retracting direction via the cam frame 12. At the same time, the shutter unit 7 and the second group frame 8 move in the retracting direction.

  During the above-described movement, the second group frame 8 is driven to rotate counterclockwise by the retraction cam toward the retraction position, and the second group lens 32 is retreated from the photographing optical path on the optical axis O. In the state in which the second group frame 8 is rotated to the retracted position, a part of the second group lens holding portion of the second group frame 8 projects outward from the opening 6c of the second group zoom frame 6 as shown in FIG. The cam frame 12 enters the escape portion 12h.

  In the state where the rotary frame 14, the moving frame 15, the cam frame 12, the first group frame 2, the second group zoom frame 6, the third group frame 16 and the like are retracted to their retracted positions, as shown in FIG. The member is retracted to a state close to close contact and is stored inside the fixed frame 17. The cam followers 51 of the first group frame 2 are engaged with the retracted position corresponding cam grooves 12c of the cam frame 12, but the rear wall surface of the retracted position corresponding cam grooves 12c is cut on the rear side of the cam follower 51. Therefore, the cam frame 12 is exposed from the rear end surface.

  In the lens barrel 1 of the present embodiment, as described above, the cam grooves 12c and 12d of the cam frame 12, and the cam grooves 12e and 12f are formed, so that the front and rear end surfaces of the cam frame 12 are scraped off and shortened. However, the first group frame 2 and the second group zoom frame 6 can be advanced and retracted along a predetermined cam line, and the shortening of the lens barrel in the retracted state can be realized. Further, since the second group frame 8 is retracted from the optical path in the retracted state, a part of the inner periphery of the cam frame 12 is made thin, so that even if the wall surface thickness of the cam groove formed in the part is reduced, it becomes a pair. By receiving an impact force acting on the cam frame 12 by the other cam groove, a reduction in impact resistance can be avoided, and at the same time, the lens barrel can be downsized.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  As described above, the zoom lens barrel of the present invention can be shortened in the lens optical axis direction in the non-shooting state, which is a retracted state, and the zoom can be reduced in the thickness of the camera to which the lens barrel is mounted. It can be used as a lens barrel.

2 ... Group frame (first moving frame)
6 ... Two-group zoom frame (second moving frame)
8 ... Second group frame (retraction frame)
9 ... Support axis (axis parallel to the optical axis)
12 ... Cam frame 12c ... Cam groove (first cam groove)
12c5 ... penetrating portion 12d ... cam groove (third cam groove)
12e, 12f ... Cam groove (second cam groove)
12h ... Thin-walled escape part (thin-wall part)
31 ... Group lens (zoom lens)
32 ... Two-group lens (zoom lens)
51. Cam follower (first cam follower)
52. Cam follower (third cam follower)
53, 54 ... Cam follower (second cam follower)
O ... Optical axis

Claims (3)

In an extendable zoom lens barrel,
A first moving frame having one zoom lens of a zoom optical system comprising a first cam follower and a third cam follower, and constituting a zoom lens;
The other zoom lens of the zoom optical system is held, and during the zoom operation when photographing is possible, the zoom lens moves on the optical axis of the zoom optical system according to the expansion / contraction operation of the zoom lens barrel, and the zoom lens During non-photographing when the lens barrel is shortened from the time when photographing is possible, a second frame having a second cam follower is supported that supports a retracting frame that retracts from the optical axis in conjunction with the shortening operation of the zoom lens barrel. Moving frame,
A bottomed first cam groove provided on a circumferential wall for rotating the first moving frame in the optical axis direction and rotating around the optical axis to come into sliding contact with the first cam follower, and the retraction A second cam groove that engages and slides on the second cam follower to retract the frame to the outside of the optical axis in conjunction with the shortening operation, and the retracting frame is retracted when the retracting frame is retracted. A thin-walled portion where the circumferential wall is thinned for operation, a part of the first cam groove disposed on the back surface of the thin-walled portion, a penetrating portion penetrating the thin-walled portion, and the first The third cam follower is slid when at least the first cam follower is positioned in the penetrating portion. A third cam groove in contact with the cam frame;
A zoom lens barrel characterized by comprising: The second moving frame moves in the optical axis direction in conjunction with the zoom operation, and supports the retracting frame so as to be rotatable about an axis parallel to the optical axis. The zoom lens barrel described in 1. The zoom lens barrel according to claim 1 or 2, wherein the third cam groove is disposed forward of the first cam groove in the optical axis direction.

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