JP5117454B2 - Support structure for biasing member of lens barrel - Google Patents

Description

  The present invention relates to a support structure for an urging member provided in a lens barrel.

  In order to remove backlash between a plurality of lens groups relatively movable in the optical axis direction, a helical coil spring (inter-group spring) is inserted between the front and rear lens group support members. A lens barrel that urges the lenses in directions away from each other is known (Patent Document 1). In addition to a spring, a lens barrel is known in which a bellows-shaped light shielding member is inserted between front and rear lens group support members (Patent Document 2).

Japanese Patent Laid-Open No. 2004-205678 JP 2002-196209 A

  The inter-group spring of Patent Document 1 is held by its elastic force with its both ends abutting against the wall surfaces of the front and rear lens group support members. However, in this holding structure, there is a possibility that the urging member may come off when a large impact is applied by dropping the lens barrel. If the urging member is removed, the lens barrel may not operate correctly, or the urging member may cause an optical adverse effect (such as subject light being blocked or harmful reflected light being generated). In Patent Document 2, mechanical engagement means such as a hook is provided on the rear surface portion of the bellows-shaped light shielding member to prevent falling off. However, such a form of falling prevention means is not formed on the coil spring. difficult. As another method for preventing dropout, the end of the coil spring may be bonded and fixed to the support member of the lens group. However, the labor and cost required for the bonding work are large, and disassembly after bonding becomes difficult. Maintenance is bad.

  The present invention is based on the above problem awareness, and a biasing member support structure for a lens barrel capable of easily and reliably holding a biasing member inserted between optical elements in a lens barrel, in particular, a coil spring. The purpose is to provide.

The present invention provides a front and rear support member that supports an optical element and is relatively movable in the optical axis direction, and an optical axis that is inserted between the front and rear support members and biases the front and rear support members in a separation direction. In a lens barrel having a surrounding coil spring, at least one of the front and rear support members has an annular abutting surface with which an annular spring end of the coil spring abuts ; the coil spring projects from the annular abutting surface in the optical axis direction. of the inner diameter movement restricting portion for restricting the movement of the inner diameter direction of the annular spring end; and the retaining can hold the holding claws the annular spring end of the coil spring between the annular abutment surface; a is provided, the holding claws, An optical axis protruding portion that protrudes from the annular contact surface in the optical axis direction and is positioned on the outer diameter side of the inner diameter movement restricting portion and restricts movement of the annular spring end of the coil spring in the outer diameter direction; Is bent in the inner diameter direction against the annular contact surface, A radially extending portion for restricting the optical axis direction movement of the annular spring end of the coil spring between; the provided annular spring end of the coil spring forms a closed end annular having an open end face facing in the circumferential direction, support through the open end face by the relative rotation of the coil spring against the member and can be inserted and removed an annular spring end between air enclosed in the annular abutment surface and the inner diameter movement restricting portion and a radially extending portion and the optical axis direction protrusions It is characterized by that.

The inner diameter movement restricting portion is preferably formed as an annular portion surrounding the optical axis .

  In addition, it is preferable to provide a plurality of holding claws at different positions in the circumferential direction.

The annular abutment surface, the holding claw, and the inner diameter movement restricting portion can be formed directly on the support member of the optical element, or a movable spring receiver supported relative to the support member in the optical axis direction. It can also be formed on a member. When the annular abutment surface, the holding claw, and the inner diameter movement restricting portion are formed on the movable spring receiving member, the position holding for holding the movable spring receiving member at a fixed position with respect to the supporting member against the urging force of the coil spring in the photographing state. Means may be provided.

  According to the present invention, it is possible to obtain a biasing member supporting structure for a lens barrel capable of easily and reliably holding a biasing coil spring inserted between optical elements.

It is sectional drawing in the zoom imaging | photography area | region (an upper half part is a wide end and a lower half part is a tele end) which shows one Embodiment of the zoom lens barrel to which this invention is applied. It is sectional drawing in the accommodation state of the zoom lens barrel. FIG. 3 is an exploded perspective view of the zoom lens barrel with the housing and the image sensor holder disassembled and the movable lens block removed. It is a disassembled perspective view of a movable lens block. It is a disassembled perspective view of a 2nd delivery cylinder and the 1st lens group supported by it. It is a back perspective view of the 2nd feeding cylinder. It is a disassembled perspective view of a 2 group lens block. It is a perspective view of the disassembled state of a 2 group lens moving frame, a variable aperture stop mechanism (variable aperture stop sub-assembly), a retaining ring, and an intergroup bias spring. (A), (B), and (C), respectively, before the variable aperture stop sub-assembly is inserted into the second group lens moving frame and the retaining ring is inserted, after the retaining ring is inserted, and by rotating the retaining ring, it is retained. It is a figure which shows a time when it was set as the state. (A), (B) is a figure which respectively shows before and after making it hold | maintain the cyclic | annular spring edge part of a group energizing spring with respect to one of the two spring holding claws of a retaining ring. (A), (B) is an enlarged view showing before and after holding the annular spring end of the intergroup bias spring with respect to one of the two spring holding claws of the retaining ring. . It is sectional drawing which expanded and showed the support structure of the rear-end part of the group energizing spring in an imaging | photography state.

  1 and 2 show an embodiment of a zoom lens barrel ZL having a biasing member support structure according to the present invention. The imaging optical system of the zoom lens barrel ZL includes a first lens group LG1, a second lens group LG2, a third lens group LG3, a low-pass filter 25, and an imaging element 26 in order from the object (subject) side. In the following description, the optical axis direction means a direction parallel to the optical axis O of the photographing optical system, the front means front in the optical axis direction (subject side), and the rear means rear in the optical axis direction (image). Surface side).

  The low-pass filter 25 and the image sensor 26 are unitized and fixed to the image sensor holder 23, and the image sensor holder 23 is fixed to the rear portion of the housing 22.

  The third group lens frame 51 that holds the third lens group LG3 is supported so as to be movable in the optical axis direction with respect to the housing 22, and is driven by an AF motor 160 (FIG. 3).

  As shown in FIG. 3, a movable lens (cam ring) block 110 is movably supported inside the housing 22. As shown in FIG. 4, the movable lens (cam ring) block 110 includes a second group linear guide ring 10, a cam ring 11, a second feeding cylinder (support member for the optical element) 12, a first feeding cylinder 13, and a cam ring. The coupling ring 14 and the second group lens block 80 are included. The cam ring 11 and the cam ring coupling ring 14 are coupled to operate as an integral member.

  The cam ring 11 has a guide protrusion 11 a that is slidably fitted into a cam ring guide groove 22 a formed on the inner peripheral surface of the housing 22. The cam ring 11 is rotated by receiving the driving force of the zoom motor 150 (FIG. 3) by the gear portion 11b, and the cam ring guide is in the period from the lens barrel storage state (FIG. 2) to the photographing state (FIG. 1). It moves in the optical axis direction while rotating under the guidance of the lead groove portion 22a1 of the groove 22a. In the zoom range in the shooting state, it is guided by the annular groove portion 22a2 of the cam ring guide groove 22a and rotates at a fixed position in the optical axis direction. Is done. FIG. 1 shows the wide end state in the upper half section and the tele end state in the lower half section.

  The first feeding cylinder 13 and the second group linear guide ring 10 are positioned in front of and behind the cam ring 11 (combined body of the cam ring 11 and the cam ring coupling ring 14). The first feeding cylinder 13 and the second group linear guide ring 10 are respectively slidably engaged with the linear guide protrusions 13a and 10a with respect to the linear guide groove 22b, so that the housing 22 is arranged in the optical axis direction. It is guided in a straight line so that it can move relatively. The second group linear guide ring 10 has a rotation guide claw 10b that engages with a rotation guide claw 11c formed on the inner peripheral surface near the rear end of the cam ring 11, and the cam ring 11 On the other hand, relative rotation is possible and they are coupled so as to move together in the optical axis direction. The first feeding cylinder 13 can be rotated relative to the cam ring 11 by the sliding contact relationship of the rotation guide claw 13 b with the rotation guide claw 14 a provided on the outer peripheral surface of the cam ring coupling ring 14 coupled to the cam ring 11. Are coupled to move together in the optical axis direction. That is, the three members of the second group linear guide ring 10, the cam ring 11, and the first feeding cylinder 13 move together in the optical axis direction, and are linearly guided to the housing 22 in the optical axis direction. The cam ring 11 is relatively rotatable with respect to the rectilinear guide ring 10 and the first feeding cylinder 13.

  The second-group linear guide ring 10 guides the second-group lens block 80 (FIG. 4) so that it can move relatively in the optical axis direction through three linear guide bars 10c protruding forward in the optical axis direction. As shown in FIG. 7, the second group lens block 80 has a second group lens moving frame (supporting member for optical elements) 8, and the optical axis direction formed on the outer surface of the cylindrical portion 8 a of the second group lens moving frame 8. When the straight guide bar 10c is slidably engaged with the straight guide groove 8b, the second group lens block 80 is guided straight. A flange portion 8c is provided inside the cylindrical portion 8a of the second group lens moving frame 8, and the second group lens holding frame 2 (FIG. 7) for holding the second lens group LG2 is supported on the inner diameter portion of the flange portion 8c. ing.

  A variable aperture stop mechanism 70 and a shutter block 100 are movably supported in the direction of the optical axis, respectively, on the second group lens moving frame 8 so as to be positioned in front of and behind the second group lens holding frame 2, respectively.

As shown in FIG. 7, the variable aperture stop mechanism 70 includes a base member (movable spring receiving member) 73, an opening / closing ring 72, a stop blade 74, and a zoom rotation ring 71. On the base member 73, a rotation center protrusion 73a (FIG. 12) that fits in the rotation center hole 74a of the three diaphragm blades 74 is formed. Each diaphragm blade 74 is formed with an opening / closing cam groove 74 b that is paired with the rotation center hole 74 a, and the opening / closing cam groove 74 b is fitted into an opening / closing pin 72 a formed to protrude from the opening / closing ring 72. When the opening / closing ring 72 rotates relative to the base member 73, the opening diameter of the aperture blade 74 changes. Specifically, when the zoom lens barrel ZL changes from the photographing state (FIG. 1) to the retracted state (FIG. 2), the radial protrusion 72b is formed by the open guide surface 12g (FIG. 6) formed on the second feeding cylinder 12. When pressed, the opening / closing ring 72 is rotated in the direction of opening the diaphragm blades 74 (hereinafter, the diaphragm opening direction). A tension coil spring 76 is stretched between the zoom rotation ring 71 and the opening / closing ring 72. When the opening / closing ring 72 rotates in the aperture opening direction, the tension coil spring 76 extends to rotate the opening / closing ring 72 independently. forgive. On the other hand, when the zoom rotation ring 71 rotates in the aperture opening direction, both the zoom rotation ring 71 and the opening / closing ring 72 are rotated. The zoom rotation ring 71 is urged to rotate in the aperture opening direction by a tension coil spring 77 stretched between the zoom rotation ring 71 and the base member 73, and the rotation control groove formed in the rectilinear guide bar 10 c of the second-group rectilinear guide ring 10. The rotational position is controlled by engaging the radial protrusion 71a with 10d. When the movable lens (cam ring) block 110 is positioned at and near the tele end of the zoom imaging region, the rotation control groove 10d does not restrict the position of the zoom rotation ring 71, and the zoom rotation ring 71 (and the opening / closing ring 72) The opening of the diaphragm blade 74 is held at the maximum opening by the urging force of the tension coil spring 77, and in the wide side region excluding the tele end and the vicinity thereof, the zoom rotation ring 71 (and the open / close ring 72) is controlled by the rotation control groove 10d. It rotates in the aperture narrowing direction, and the aperture diameter by the aperture blade 74 is minimized.

The base member 73, the opening / closing ring 72, the diaphragm blade 74, the zoom rotating ring 71, and the tension coil springs 76 and 77 constituting the variable aperture stop mechanism 70 are assembled as a variable aperture stop sub-assembly SA as shown in FIG. 8 and 9, it is inserted into the front opening of the flange portion 8c of the second group lens moving frame 8 and supported through a retaining ring (movable spring receiving member) 75. That is, a guide protrusion 73b (FIGS. 7 and 8) protruding in the radial direction is formed on the base member 73, and a rectilinear guide groove 8e (FIG. 7, FIG. 7) in which the guide protrusion 73b is fitted in the second group lens moving frame 8. FIG. 8) is formed. The second group lens moving frame 8 is also formed with a plurality of retaining projections (position holding means) 8f protruding radially inward from the cylindrical wall surface of the front opening of the flange portion 8c (the inner peripheral surface of the cylindrical portion 8a). The retaining ring 75 is formed with an assembly groove 75b whose position coincides with the retaining projection 8f on the outer peripheral portion of a plate-shaped annular body (annular contact surface) 75a substantially orthogonal to the optical axis O. Yes. The retaining ring 75 is provided with a compression coil spring (position holding means) 78 that moves and biases the variable aperture stop sub-assembly SA forward between the base member 73 and the second group lens moving frame 8. The projection 8f and the assembly groove 75b are used to support the front opening inner surface of the flange portion 8c of the second group lens moving frame 8. Further, the base member 73 is formed with an anti-rotation protrusion 73 c, and an anti-rotation U groove 75 c is formed on the outer peripheral portion of the annular main body 75 a of the retaining ring 75. When the rotation phases of the assembly groove 75b and the retaining protrusion 8f coincide with each other, the rotation prevention protrusion 73c and the rotation prevention U groove 75c do not coincide with each other, and their positions coincide with each other at another rotation phase. The base member 73, with the retaining ring 75 assembled, is positioned on the inner side of the annular main body 75 a and has an annular front projecting ring portion (inner diameter movement restricting portion) 73 d surrounding the optical axis O, and the rear of the retaining ring 75. The flange part 73e located in is provided. The anti-rotation protrusion 73c and the forward projecting ring portion 73d protrude from the flange portion 73e toward the front.

  FIG. 9 shows a step of fitting the variable aperture stop sub-assembly SA and the retaining ring 75 to the second group lens moving frame 8. FIG. 4A shows a state where the variable aperture stop sub-assembly SA is fitted by engaging the guide protrusion 73b of the base member 73 with the straight guide groove 8e of the front opening of the second group lens moving frame 8. FIG. 5B shows a state in which the retaining ring 75 is inserted with the rotational phases of the assembly groove 75b of the retaining ring 75 and the retaining protrusion 8f of the second group lens moving frame 8 being matched. In this state, when the retaining ring 75 is rotated at a small angle relative to the second group lens moving frame 8, a part of the annular main body 75a of the retaining ring 75 enters the back surface of the retaining protrusion 8f, and the compression coil spring 78 is moved. The retaining ring 75 and the variable aperture stop sub-assembly SA are prevented from coming off against the urging force. At this time, the rotation preventing projection 73c of the base member 73 is fitted into the rotation preventing U groove 75c of the retaining ring 75, and the rotation of the retaining ring 75 is restricted. In this retaining state, the retaining ring 75 and the variable aperture stop sub-assembly SA are guided so as to be movable in the optical axis direction with respect to the second group lens moving frame 8.

  The second feeding cylinder 12 is provided with a flange portion 12b inside the cylindrical portion 12a, and the first lens group LG1 is held on the inner diameter portion of the flange portion 12b. As shown in FIGS. 5 and 6, the cylindrical portion 12a and the flange portion 12b are respectively provided with an outer straight guide key 12c and an inner straight guide key 12d that protrude rearward. The outer rectilinear guide key 12c is engageable with a rectilinear guide groove 13c (FIG. 4) formed on the inner peripheral surface of the first feeding cylinder 13, and the inner rectilinear guide key 12d is a cylindrical portion of the second group lens moving frame 8. It can be engaged with a rectilinear guide groove 8d (FIG. 7) formed on the inner peripheral surface of 8a. Due to the sliding relationship between the rectilinear guide grooves 13c, 8d and the rectilinear guide keys 12c, 12d, the second feeding cylinder 12 is guided in a straight manner so as to be movable relative to the housing 22 in the optical axis direction.

  The second feed cylinder 12 includes a first group cam follower CF1 protruding in the inner diameter direction behind the outer straight guide key 12c, and the first group cam follower CF1 is formed on the outer peripheral surface of the cam ring 11. It is slidably engaged with CG1. Since the second feeding cylinder 12 is linearly guided in the optical axis direction via the first feeding cylinder 13 and the second group lens moving frame 8, when the cam ring 11 rotates, the second feeding cylinder 12, that is, the first lens group LG1. Moves along a predetermined locus in the optical axis direction.

  The second group cam follower CF2 provided on the outer peripheral surface of the cylindrical portion 8a of the second group lens moving frame 8 is engaged with the second group control cam groove CG2 formed on the inner peripheral surface of the cam ring 11. Since the second group lens moving frame 8 is guided linearly in the optical axis direction via the second group linear guide ring 10, when the cam ring 11 rotates, the second group lens moving frame 8 follows the shape of the second group control cam groove CG2. 8, that is, the second lens group LG2 moves along a predetermined locus in the optical axis direction.

  An intergroup biasing spring (coil spring) 27 is inserted between the second group lens moving frame 8 and the second feeding cylinder 12, and the second group lens moving frame 8 and the second feeding cylinder 12 are separated from each other. It is energized. Due to the biasing force of the intergroup biasing spring 27, a support guide mechanism for the first lens group LG1 and the second lens group LG2 (for example, between the first group control cam groove CG1 and the first group cam follower CF1, the second group control cam groove). Backlash in CG2 and the second group cam follower CF2) can be taken.

  A support structure of the intergroup bias spring 27 will be described. The intergroup biasing spring 27 is a compression coil spring that spirally decreases in diameter as it advances from the front to the rear in the optical axis direction, and its front end abuts against the rear surface of the flange portion 12 b of the second feeding cylinder 12. More specifically, three rear projecting portions 12e having a partial cylindrical shape having the inner straight guide key 12d described above on the outer peripheral surface project from the flange portion 12b to the rear, and three rear projecting portions 12e are projected on the rear surface of the flange portion 12b. An annular recess 12f (FIGS. 1, 2, and 6) centering on the optical axis O is formed in the immediate vicinity of the rear protrusion 12e. The front end portion of the intergroup biasing spring 27 is fitted and supported in the annular recess 12f, and is prevented from falling off in the outer diameter direction by the three rear protrusions 12e.

On the other hand, the rear end portion of the intergroup biasing spring 27 abuts against a retaining ring 75 of the variable aperture stop mechanism 70 supported by the front opening of the second group lens moving frame 8. As shown in FIGS. 7 to 11, the retaining ring 75 is provided with two spring holding claws 75 d at different positions in the circumferential direction. As can be seen from FIGS. 11 and 12, each spring retaining pawl 75d is formed by cutting and raising a part of the inner diameter side of the annular main body 75a of the retaining ring 75, and facing forward from the annular main body 75a. An L-shape having a front projecting portion (optical axis projecting portion) 75d1 projecting and a radially extending portion (radially extending portion) 75d2 bent from the front projecting portion 75d1 in the inner diameter direction, A spring end insertion space 75e is formed between the radially extending portion 75d2 and the annular main body 75a. As shown in FIG. 12, the front protrusion 75d1 of the spring holding claw 75d is positioned on the outer diameter side of the spring end insertion space 75e, and the front protrusion ring portion 73d of the base member 73 is positioned on the inner diameter side. In addition, a recessed portion 73f that allows the front end portion (inner diameter portion) of the radially extending portion 75d2 of the spring holding claw 75d to enter is formed in the forward projecting ring portion 73d of the base member 73.

  As shown in FIG. 10, the intergroup bias spring 27 has an annular spring end portion 27 a that abuts against the front surface of the annular main body portion 75 a of the retaining ring 75 at the rear end portion. The annular spring end portion 27a is composed of a closed coiled coil portion having a winding amount of at least one rotation starting from the open end portion 27b opened in the circumferential direction. That is, in the free state of the inter-group biasing spring 27, the adjacent spring winding portions in the optical axis direction are in close contact with each other at the annular spring end portion 27a. On the other hand, the front portion of the annular spring end portion 27a is a coarsely wound coil portion 27c in which adjacent spring winding portions in the optical axis direction are separated in the free state of the intergroup biasing spring 27. When the second feeding cylinder 12 supporting the first lens group LG1 and the second group lens block 80 supporting the second lens group LG2 move relative to each other in the optical axis direction, the coarsely wound coil portion 27c expands and contracts between the groups. The length of the biasing spring 27 changes.

  When the group biasing spring 27 is assembled, first, the annular spring end portion 27a (open end portion 27b) and the spring holding claw 75d (spring end portion insertion space 75e) are arranged so that the radial positions thereof substantially coincide with each other. The end 27 a is brought into contact with the annular main body 75 a of the retaining ring 75. When the inter-group biasing spring 27 is rotated relative to the second group lens block 80 in a direction in which the open end 27b approaches the spring holding claw 75d, the annular spring end 27a starts from the open end 27b. The spring end insertion space 75e is inserted. 10A and 11A, in one of the two spring holding claws 75d, the annular spring end 27a has already been inserted (passed) into the spring end insertion space 75e, and the remaining one The state immediately before the open end surface 27b of the annular spring end 27a is inserted into the spring end insertion space 75e of the spring holding claw 75d is shown. FIGS. 10B and 11B show a state in which the annular spring end 27a is also inserted into the spring end insertion space 75e of the second spring holding claw 75d. In this state, as shown in FIG. 12, the annular spring end portion 27a is sandwiched between the annular main body portion 75a of the retaining ring 75 and the radially extending portion 75d2 of the two spring holding claws 75d, and is in the optical axis direction. Dropout is restricted, and dropout in the outer diameter direction is also restricted by the front protrusion 75d1 of each spring holding claw 75d. In addition, the annular spring end portion 27 a is also restricted from dropping in the inner diameter direction by the forward projecting ring portion 73 d of the base member 73. As a result, the annular spring end 27a of the intergroup biasing spring 27 is held in a manner that is prevented from dropping in any direction with respect to the second group lens block 80 (variable aperture stop mechanism 70). As can be seen from FIG. 1, the rear projecting portion 12e of the second feeding cylinder 12 is formed long on the front end portion side of the intergroup biasing spring 27. Therefore, when an impact is applied from the outside, the rear projecting portion is formed. It is difficult to cause a situation where the front end of the intergroup biasing spring 27 falls off over 12e. On the other hand, on the rear end side of the intergroup biasing spring 27, both the second group lens moving frame 8 and the base member 73 (variable aperture stop mechanism 70) have an overlap amount in the optical axis direction with respect to the intergroup biasing spring 27. However, the intergroup biasing spring 27 is prevented from falling off by holding the annular spring end 27a by the spring holding claw 75d of the retaining ring 75 instead. The holding state of the annular spring end 27a by the spring holding claw 75d does not require adhesion, and can be obtained by simply rotating the group biasing spring 27 relative to the retaining ring 75. The assembly work of the spring 27 can be easily performed.

  With the inter-group bias spring 27 attached as described above, the force of the inter-group bias spring 27 and the compression coil spring 78 acts on the front and back (front and rear) of the retaining ring 75. The total force of 78 is larger than the force of the inter-group biasing spring 27. Therefore, in a normal state where the force in the optical axis direction is not applied to the variable aperture stop sub-assembly SA (zoom shooting state), the retaining ring 75 (variable aperture) The stop sub-assembly SA) is maintained at the forwardly extending end (the state shown in FIG. 1) where the retaining protrusion 8f and the annular main body 75a of the retaining ring 75 abut. In other words, in the photographing state, the retaining ring 75 is held at the forward advancing end against the urging force of the inter-group urging spring 27, and the second lens group moving frame 8 is moved between the groups via the retaining ring 75. The urging force to the rear in the optical axis direction by the urging spring 27 acts. In the storage position, the variable aperture stop sub-assembly SA is retracted while contracting the compression spring 78 by a part of the second feeding cylinder 12, and the retaining ring 75 is separated from the retaining protrusion 8f (FIG. 2).

  The zoom lens barrel ZL having the above structure operates as follows. 2, the length of the optical system in the optical axis direction (distance from the object side surface of the first lens group LG1 to the imaging surface of the image sensor 26) is larger than that in the imaging state shown in FIG. It is getting shorter. In the lens barrel retracted state, the intergroup bias spring 27 has a compressed length in the optical axis direction of the coarsely wound coil portion 27c.

  When a transition signal to the photographing state in the lens barrel storage state (for example, a main switch provided in a camera on which the zoom lens barrel ZL is mounted) is input, the zoom motor 150 is driven in the lens barrel feeding direction, Due to the relationship between the lead groove portion 22a1 of the cam ring guide groove 22a and the guide projection 11a, the cam ring 11 is extended forward in the optical axis direction while rotating with respect to the housing 22. The rectilinear guide ring 10 and the first feed cylinder 13 move straight forward together with the cam ring 11, and the first feed cylinder 13 gradually increases the amount of protrusion from the housing 22.

  When the cam ring 11 rotates, on the outer side, the second feeding cylinder 12 guided in a straight line in the optical axis direction is connected to the cam ring 11 and the first feeding cylinder by the relationship between the first group control cam groove CG1 and the first group cam follower CF1. 13 and the second group guide linear guide ring 10 are fed forward in the optical axis direction, and the second feed cylinder 12 gradually increases the amount of projection from the first feed cylinder 13. Further, when the cam ring 11 is rotated, the second group lens moving frame 8 guided linearly through the second group linear guide ring 10 is moved inside by the relationship between the second group cam follower CF2 and the second group control cam groove CG2. The cam ring 11 is moved in the optical axis direction along a predetermined locus different from that of the second feeding cylinder 12. The relative movement of the second group lens moving frame 8 and the second feeding cylinder 12 increases the distance between the optical axis directions of each other, and the coarsely wound coil portion 27c of the group biasing spring 27 is gradually increased accordingly. Extends in the direction of the optical axis.

  Eventually, when the zoom lens barrel ZL is extended by a predetermined amount, the guide projection 11a of the cam ring 11 enters the annular groove portion 22a2 of the cam ring guide groove 22a, and the movement of the cam ring 11 in the optical axis direction is stopped. Shortly after the cam ring 11 is in this fixed position rotation state, it reaches the wide end of the zoom photographing region shown in the upper half section of FIG. As can be seen from the figure, even when the inter-group biasing spring 27 is extended, the annular spring end 27a at the rear end thereof is prevented from coming off by the spring holding claw 75d, so that it may come off even when an impact is applied from the outside. There is no. The front end portion of the intergroup bias spring 27 is also prevented from falling off by the rear protruding portion 12e of the second feeding cylinder 12. When the zoom motor 150 is driven from the wide end extended state in the telephoto direction (the same direction as when extended from the lens barrel storage state to the wide end), the inter-group biasing spring 27 is gradually compressed, and eventually FIG. The telephoto end is shown in the lower half section. In the zoom photographing region from the wide end to the tele end, the cam ring 11 rotates at a fixed position in the optical axis direction by the guide protrusion 11a being guided by the annular groove portion 22a2 of the cam ring guide groove 22a. Do not advance or retreat.

  The first lens group LG1 and the second lens group LG2 are fed out from the lens barrel retracted state by the former moving amount of the cam ring 11 with respect to the housing 22 and the cam of the second feeding cylinder 12 with respect to the cam ring 11, respectively. The latter is determined as the sum of the amount of forward movement of the cam ring 11 relative to the housing 22 and the amount of cam extension of the second group lens moving frame 8 relative to the cam ring 11. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 along the photographing optical axis O while changing the air interval between them. The intergroup bias spring 27 expands and contracts in accordance with zooming, but the holding of the annular spring end 27a by the spring holding pawl 75d is maintained at any focal length.

  When a transition signal from the shooting state (zoom shooting area) to the storage state (for example, turning off the main switch of the camera) is input, the zoom motor 150 is driven in the lens barrel storage direction, and the zoom lens barrel ZL The storing operation opposite to the feeding operation is performed. The cam ring 11 is moved rearward in the optical axis direction while rotating in response to the guide of the lead groove portion 22 a 1 of the cam ring guide groove 22 a, and the first feeding cylinder 13 and the rectilinear guide ring 10 are moved along the cam ring 11 in the optical axis direction. It is moved straight back. The second feeding cylinder 12 is further moved rearward in the optical axis direction with respect to the cam ring 11 that is moving backward, with the first group cam follower CF1 receiving the guidance of the first group control cam groove CG1. Further, the second group lens block 80 (second group lens moving frame 8) holding the second lens group LG2 is second extended with respect to the cam ring 11 by the relationship between the second group cam follower CF2 and the second group control cam groove CG2. It is relatively moved in the optical axis direction along a predetermined locus different from that of the cylinder 12. The group biasing spring 27 is compressed by the approach of the second feeding cylinder 12 and the second group lens block 80. Further, as described above, in the storage position, the variable aperture stop sub-assembly SA is retracted while contracting the compression spring 78 by a part of the second feeding cylinder 12, and the retaining ring 75 is separated from the retaining protrusion 8f.

  The third lens group frame 51 that supports the third lens group LG3 is moved back and forth in the optical axis direction by the AF motor 160 independently of the driving of the first lens group LG1 and the second lens group LG2 by the zoom motor 150 described above. Can be made. Then, when the optical system is in the zoom photographing area from the wide end to the tele end, the third lens group LG3 is moved in the optical axis direction by driving the AF motor 160 according to the subject distance information obtained by the distance measuring means. To move to and focusing is executed.

As described above, in the zoom lens barrel ZL of the present embodiment, the spring holding claw 75d provided with the annular spring end 27a constituting the rear end of the intergroup biasing spring 27 on the retaining ring 75 on the second group lens block 80 side. In addition, since it is held by the forward projecting ring portion 73d provided on the base member 73, the intergroup biasing spring 27 can be prevented from falling off even when an impact is applied from the outside. The holding state (and release of the holding state) of the annular spring end 27a by the spring holding claw 75d and the forward projecting ring portion 73d can be easily obtained by relative rotation of the intergroup biasing spring 27 and the retaining ring 75. Also, workability is excellent.

As mentioned above, although demonstrated based on illustration embodiment, this invention is not limited to this embodiment. For example, in the illustrated embodiment, the retaining ring 75 for retaining the variable aperture stop mechanism 70 at the front portion of the second group lens block 80 (second group lens moving frame 8) is the annular spring end of the intergroup biasing spring 27. Although it also serves as a member for abutting and holding the portion 27a, it is not a movable member for the second group lens moving frame 8 such as the retaining ring 75, but the second group lens moving frame 8 itself contacts the annular spring end 27a. You may provide the part which contacts and hold | maintains. For example, unlike the embodiment, assuming that the variable aperture stop mechanism 70 does not exist in the front part of the second group lens block 80, the annular spring end 27a is brought into contact with the flange portion 8c of the second group lens moving frame 8. Further, a mode in which a portion corresponding to the spring holding claw 75d is formed on the front surface of the flange portion 8c is also possible. Further, a mode in which a portion corresponding to the forward projecting ring portion 73 d of the base member 73 is formed in the flange portion 8 c of the second group lens moving frame 8 is also possible.

  In the embodiment, the retaining ring 75 is provided with two L-shaped spring holding claws 75d. However, if sufficient fall prevention performance is obtained, the number and shape of the holding claws in the present invention are not limited thereto. It is not limited.

  In the embodiment, the spring holding claw 75d is applied as a holding structure for the annular spring end portion 27a on the rear end side of the intergroup biasing spring 27. However, a similar holding structure is provided on the front end side of the intergroup biasing spring 27. You may apply.

  The embodiment is an example applied to a zoom lens barrel, but the present invention can also be applied to a lens barrel other than a zoom lens system.

8 2 group lens moving frame (supporting member for optical element)
8f Protrusion protrusion (position holding means)
10 2nd group linear guide ring 11 Cam ring 12 Second feed cylinder (supporting member for optical element)
12e Backward projecting portion 12f Annular recess 13 First feeding cylinder 14 Cam ring coupling ring 22 Housing 23 Imaging element holder 27 Inter-group biasing spring (coil spring)
27a Annular spring end portion 27b Open end surface 27c Coarse winding coil portion 70 Variable aperture stop mechanism 71 Zoom rotation ring 72 Opening / closing ring 73 Base member (movable spring receiving member)
73c Non-rotating projection 73d Forward projecting ring part (inner diameter movement restricting part)
73f Concave 74 Stopper blade 75 Stop ring (movable spring receiving member)
75a Annular body (annular contact surface)
75b Assembly groove 75c Non-rotating U groove 75d Spring holding claw 75d1 Front protrusion (optical axis direction protrusion)
75d2 radially extending portion (radially extending portion)
75e Spring end insertion space 78 Compression coil spring (position holding means)
80 Second group lens block 110 Movable lens (cam ring) block 150 Zoom motor 160 AF motor CF1 First group cam follower CF2 Second group cam follower CG1 First group control cam groove CG2 Second group control cam groove LG1 First lens group LG2 Second lens Group LG3 Third lens group O Optical axis SA Variable aperture stop Sub-assembly ZL Zoom lens barrel

Claims (4)

Front and rear support members that support the optical element and are relatively movable in the optical axis direction;
A coil spring that surrounds the optical axis and is inserted between the front and rear support members to urge the front and rear support members in the separating direction;
In a lens barrel having
At least one of the front and rear support members,
An annular contact surface against which the annular spring end of the coil spring abuts ;
An inner diameter movement restricting portion that protrudes from the annular contact surface in the optical axis direction and restricts movement of the annular spring end of the coil spring in the inner diameter direction;
And retaining can hold the holding claws the annular spring end of the coil spring between said annular abutment surface;
With
The holding claw is
An optical axis direction protrusion that protrudes in the optical axis direction from the annular abutment surface and is positioned on the outer diameter side of the inner diameter movement restricting portion and restricts movement of the annular spring end of the coil spring in the outer diameter direction;
A diameter that is bent in the inner diameter direction with respect to the projecting portion in the optical axis direction, faces the annular contact surface, and restricts movement of the annular spring end portion of the coil spring in the optical axis direction between the annular contact surface. A direction extending part;
With
The annular spring end portion of the coil spring has an end ring shape having an open end surface facing in the circumferential direction, and the annular abutment surface and the inner diameter movement restricting portion through the open end surface by relative rotation of the coil spring with respect to the support member. the radially extending portion and the optical axis, characterized in that the removably to the annular spring end between air enclosed in the direction projecting portions, the biasing member support structure of a lens barrel and. The urging member support structure for a lens barrel according to claim 1, wherein the inner diameter movement restricting portion has an annular shape surrounding the optical axis . 3. The lens barrel urging member support structure according to claim 1, wherein a plurality of the holding claws are provided at different positions in the circumferential direction. In urging member support structure of a lens barrel according to any one of claims 1 to 3, the annular abutment surface and the retaining pawl and the inner diameter movement restricting portion in the optical axis direction with respect to the support member Formed on a movable spring receiving member supported so as to be relatively movable;
An urging member support structure for a lens barrel having position holding means for holding the movable spring receiving member at a fixed position with respect to the support member against an urging force of the coil spring in a photographing state.

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