JP2004258637A - Advance/retreat cam mechanism for lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an advance/retreat cam mechanism for a lens barrel where the miniaturization of a cam ring is made compatible with the securing of the moving amount of a movable member. <P>SOLUTION: In the advance/retreat cam mechanism for the lens barrel equipped with a movable member supporting an optical element and guided to advance straight in the optical axis direction, and a cam ring having a cam groove which a cam follower arranged on the movable member is engaged with on its peripheral surface, either front or rear end of the cam groove is opened to the end face of the cam ring, and the cam follower is made to retreat/advance in the open end of the cam groove in accordance with the normal and reverse rotation of the cam ring. The cam mechanism is provided with a movement regulation part restricting the leaving or the leaving amount of the cam follower to the outside of the cam groove from the open end of the cam groove. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an advance / retreat cam mechanism mounted on a lens barrel.

  A cam follower is provided on the movable member guided straight, a cam groove is formed on the peripheral surface of the cam ring, and the cam follower is guided by the cam groove to move the movable member back and forth in the rotation axis direction of the cam ring. Basically, the amount of forward and backward movement of the movable member is smaller than the length of the cam ring in the rotation axis direction. For example, when the cam groove has a shape that is closed with respect to the front and rear end surfaces of the cam ring, the cam ring covers the front and rear ends of the cam groove in addition to the cam groove formation area in the rotation axis direction. Only the thickness is required. The front and rear thickness securing regions cannot be used as a moving range of the cam follower because no cam groove is formed. Strictly speaking, the moving range of the cam follower in the rotation axis direction of the cam ring is obtained by subtracting the diameter of the cam follower itself from the cam groove forming area. Therefore, assuming that the thickness of the front and rear ends of the cam ring required to close the cam groove is A and B, the diameter of the cam follower is C, and the effective length (front and rear width) of the cam ring in the rotation axis direction is D, The maximum movement amount E in the direction is E = DABC. When an opening for assembling a cam follower is provided in the cam groove, one end of the cam groove extends through one of the front and rear thickness securing portions A and B. Since this area is used only during assembly and disassembly, it is not used for controlling the movement of the movable member in use. Therefore, even when one end of the cam groove is opened for assembling the cam follower, the substantial maximum movement amount of the movable member is the same as the above expression.

  The above-mentioned reciprocating cam mechanism is often used for a lens barrel. However, in recent lens barrels, it is necessary to increase a moving amount of a movable member such as a lens frame in an optical axis direction in order to achieve a high zoom ratio. However, there is also a strong demand for miniaturization of the lens barrel. For example, in order to increase the maximum movement amount (E) of a movable member such as a lens frame in the optical axis direction, simply increase the effective length (D) of the cam ring. Is contrary to the demand for miniaturization of the lens barrel. SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrel advancing / retracting cam mechanism capable of satisfying conflicting demands for downsizing a cam ring and securing a moving amount of a movable member.

  SUMMARY OF THE INVENTION The present invention is directed to a lens barrel having a movable member that supports an optical element and is guided in a straight line in an optical axis direction, and a cam ring having a cam groove formed on a peripheral surface thereof with a cam follower provided on the movable member. In the cam mechanism, one of the front and rear ends of the cam groove is opened to the end face of the cam ring, and the cam follower is advanced and retracted into the open end of the cam groove in accordance with the forward / reverse rotation of the cam ring to open the cam groove. The cam follower is characterized in that it has a movement restricting portion that limits the detachment or the detachment amount of the cam follower from the end to the outside of the cam groove.

  In a mode in which the cam follower is located within the open end of the cam groove in a standby state in which photographing is not performed, the movement restricting unit restricts the cam follower from falling off from the open end of the cam groove, and the cam follower opens the cam groove in the standby state. In a mode in which the cam follower is detached from the end, the cam follower may be made to function to limit the amount of separation of the cam follower from the open end of the cam groove.

  Further, in a mode in which the cam follower is located within the open end of the cam groove in a standby state in which photographing is not performed, it is preferable that the open end of the cam groove is formed wider than other regions of the cam groove.

  The present invention is suitable for a zoom lens barrel of a type that can be stored in a camera body, and stores a state in which a cam follower is located in an open end of a cam groove or a state in which the cam follower is separated from the open end. Good condition.

  The movement restricting section is preferably provided on the movable member and the cam ring. For example, the movable member may be a movable ring that is substantially concentric with the cam ring, and the movement restricting portion may be any one of a convex portion protruding from the cam groove forming peripheral surface of the cam ring and a movable ring that can contact the convex portion. End face. The movement restricting portion may also include a convex portion of the movable ring protruding from the peripheral surface of the movable ring facing the cam ring, and any one of front and rear end surfaces of the cam ring that can contact the convex portion. It is also possible to provide these two types of movement restriction parts at the same time.

  In the cam groove, another open end for assembling the cam follower may be formed on the side opposite to the above open end where the cam follower advances and retreats by controlling the rotation of the cam ring.

  The present invention is also directed to a lens barrel including a movable member that supports an optical element and is guided in a straight line in the optical axis direction, and a cam ring having a cam groove formed on a peripheral surface of the movable member and engaged with a cam follower. In the reciprocating cam mechanism, one of the front and rear ends of the cam groove is opened to the end face of the cam ring, and in a standby state where photographing is not performed, the cam groove separated from the open end of the cam groove or from the open end. A cam follower is located outside of the cam ring, and in this standby state, a movement restricting portion that determines a moving end of the movable member in the opening direction of the cam groove opening end with respect to the cam ring is provided.

  The present invention also includes a movable member that supports the optical element and is guided in a straight line in the optical axis direction, and a cam ring having a cam groove on a peripheral surface with which a cam follower provided on the movable member is engaged. In an advancing / retracting cam mechanism of a lens barrel having a shooting control area for positioning a movable member at a shooting-possible position and a shooting standby area for positioning at a shooting different from the shooting-possible position, a cam is provided at one of front and rear ends of a cam groove. Opened to the end face of the ring, this open cam groove area is used as a shooting standby area, and when the cam follower is located in the shooting standby area, the movable member relative to the cam ring in the direction in which the cam follower comes off from the open portion of the shooting standby area. It is characterized in that a movement restricting section for restricting movement is provided.

  The present invention also includes a movable member that supports the optical element and is guided in a straight line in the optical axis direction, and a cam ring having a cam groove on its peripheral surface with which a cam follower provided on the movable member is engaged. When the cam groove moves the movable member between the photographable position and the photographing standby position by the cam groove, one of the front and rear ends of the cam groove is opened to the end surface of the cam ring, and the movable member In the photographing standby position, the cam follower is separated from the open end of the cam groove, and when the cam follower is separated from the open end of the cam groove, the cam follower moves away from the open end of the cam groove. It is characterized in that a movement restricting portion for restricting the relative movement of the movable member is provided.

  As described above, according to the present invention, it is possible to obtain an advancing / retracting cam mechanism that achieves both reduction in the size of the cam ring and securing the amount of movement of the movable member.

  Hereinafter, the present invention will be described based on the illustrated embodiments. Note that in some drawings, the thickness of the external line is different or the line type is different for each member in order to easily identify the members. In addition, in the cross-sectional views, there are actually different positions in the circumferential direction, but there are some portions that are shown on the same cross-section in the drawing.

[Overall description of lens barrel]
First, the overall structure of the zoom lens barrel 71 of the present embodiment will be described with reference to FIGS. As shown in FIGS. 6 and 7, the zoom lens barrel 71 is mounted on the digital camera 70, and the photographing optical system includes, in order from the object side, a first lens group LG1, a shutter S and an aperture A, and a second lens. The optical system includes a group LG2, a third lens group LG3, a low-pass filter (filters) LG4, and a CCD (solid-state imaging device) 60. The optical axis of the photographing optical system is Z1. The photographing optical axis Z1 is parallel to the rotation center axis (hereinafter, referred to as the barrel center axis Z0) of each of the annular members constituting the appearance of the zoom lens barrel 71, and is parallel to the barrel center axis Z0. Eccentric downward. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 back and forth along a predetermined trajectory in the direction of the photographing optical axis Z1, and focusing is performed by moving the third lens group LG3 in the same direction. In the following description, the term “optical axis direction” means a direction parallel to the photographing optical axis Z1 unless otherwise specified.

  As shown in FIGS. 6 and 7, the fixed ring 22 is fixed in the camera body 72, and the CCD holder 21 is fixed to the rear of the fixed ring 22. The CCD 60 is supported on the CCD holder 21 via a CCD base plate 62, and a low-pass filter LG 4 is supported in front of the CCD 60 via a filter holder 73 and a packing 61. The filter holder 73 is integrally formed as a part of the CCD holder 21. An LCD 20 for displaying images and photographing information is provided at the rear of the CCD holder 21.

  An AF lens frame (third group lens frame) 51 that holds the third lens group LG3 is supported in the fixed ring 22 so as to be able to move straight in the optical axis direction. That is, the front end and the rear end of a pair of AF guide shafts 52 and 53 parallel to the photographing optical axis Z1 are fixed to the fixed ring 22 and the CCD holder 21, respectively. Guide holes 51a and 51b formed in the AF lens frame 51 are slidably fitted respectively. In the present embodiment, the clearance between the AF guide shaft 53 and the guide hole 51b is larger than the clearance between the AF guide shaft 52 and the guide hole 51a. That is, the AF guide shaft 52 is a main (exactly accurate) guide shaft, and the AF guide shaft 53 is a sub (non-rotating) guide shaft. The AF nut 54 is screwed into a feed screw formed on the drive shaft of the AF motor 160. As shown in FIG. 1, the AF nut 54 has a rotation restricting protrusion 54a, the AF lens frame 51 has a guide groove 51m in the optical axis direction, and the rotation restricting protrusion 54a can slide with respect to the guide groove 51m. Is stuck in. The AF lens frame 51 further has a stopper projection 51n located behind the AF nut 54. The AF lens frame 51 is urged forward by an AF frame urging spring 55, and the forward movement end of the AF lens frame 51 is determined by the stopper projection 51 n abutting against the AF nut 54. When the AF nut 54 moves rearward in the optical axis direction, the AF lens frame 51 is pressed by the AF nut 54 and moves rearward. With the above structure, when the drive shaft of the AF motor 160 is rotated in the normal or reverse direction, the AF lens frame 51 is moved forward and backward in the optical axis direction. It is also possible to directly press the AF lens frame 51 (without using the AF nut 54) and move the AF lens frame 51 backward against the AF frame urging spring 55.

  As shown in FIG. 5, a zoom motor 150 and a reduction gear box 74 are supported on the upper part of the fixed ring 22. The reduction gear box 74 has a reduction gear train therein and transmits the driving force of the zoom motor 150 to the zoom gear 28. The zoom gear 28 is pivotally attached to the fixed ring 22 by a zoom gear shaft 29 parallel to the photographing optical axis Z1. The zoom motor 150 and the AF motor 160 are controlled by a camera control circuit 140 (FIG. 19) via a lens drive control FPC (flexible printed circuit) board 75 disposed on the outer peripheral surface of the fixed ring 22.

  On the inner peripheral surface of the fixed ring 22, a female helicoid 22a, three rectilinear guide grooves 22b parallel to the photographing optical axis Z1, three oblique grooves 22c parallel to the female helicoid 22a, and each oblique groove 22c are formed. A circumferential sliding groove 22d communicating with the front end is formed in the circumferential direction. The rotary sliding groove 22d is formed near the front end of the fixed ring 22, and the female helicoid 22a is not formed in the front annular region 22z immediately after the rotary sliding groove 22d (see FIG. 8).

  The helicoid ring 18 has a male helicoid 18a screwed into the female helicoid 22a and a rotary sliding projection 18b located in the oblique groove 22c and the rotary sliding groove 22d on the outer peripheral surface (FIG. 4, FIG. (FIG. 9). A spur gear portion 18c having gear teeth parallel to the photographing optical axis Z1 is formed on the male helicoid 18a, and the spur gear portion 18c is screwed with the zoom gear 28. Accordingly, when a rotational force is applied from the zoom gear 28 to the spur gear portion 18c, the helicoid ring 18 advances and retreats in the optical axis direction while rotating when the female helicoid 22a and the male helicoid 18a are in a screwing relationship with each other. When the male helicoid 18a moves, the male helicoid 18a is disengaged from the female helicoid 22a, and only the circumferential rotation about the lens barrel center axis Z0 is performed by the engagement relationship between the rotary sliding groove 22d and the rotary sliding protrusion 18b.

  The skew groove 22c is a relief groove formed to avoid interference between the rotary sliding protrusion 18b and the fixed ring 22 when the female helicoid 22a and the male helicoid 18a are screwed, and the skew groove 22c is a female helicoid 22a. Is deeper than the bottom. In the female helicoid 22a, the circumferential interval between a pair of helicoid mountains sandwiching each of the oblique grooves 22c is wider than the circumferential interval between the other helicoid mountains, and the male helicoid 18a is mounted on the helicoid mountain having the wide circumferential interval. For engagement, the three helicoid peaks 18a-W located behind the rotary sliding protrusion 18b are circumferentially wider than the other helicoid peaks.

  The fixed ring 22 is further formed with a stopper insertion / removal hole 22e penetrating the outer peripheral surface and the rotary sliding groove 22d, and restricts the rotation of the helicoid ring 18 beyond the photographing area with respect to the stopper insertion / removal hole 22e. To be disassembled is removable.

  A rotation transmitting projection 15a (FIG. 11) projecting rearward from the rear end of the third outer cylinder 15 fits into a rotation transmitting recess 18d (FIGS. 4 and 10) formed on the inner peripheral surface of the front end of the helicoid ring 18. Have been. The rotation transmitting recesses 18d and the rotation transmitting projections 15a are provided at three positions at different positions in the circumferential direction, and the rotation transmitting projections 15a and the rotation transmitting recesses 18d corresponding to the circumferential positions correspond to the center axis of the lens barrel. Relative sliding in the direction along Z0 is connected so as to be possible, and relative rotation is not possible in the circumferential direction around the lens barrel center axis Z0. That is, the third outer cylinder 15 and the helicoid ring 18 rotate integrally. Further, the helicoid ring 18 is formed with a fitting recess 18e by cutting out a part of the rotation sliding protrusion 18b on the inner diameter side, and the fitting protrusion 15b fitted into the fitting recess 18e is rotated. When the sliding protrusion 18b engages with the rotating sliding groove 22d, it simultaneously engages with the rotating sliding groove 22d (see the upper half section of the lens barrel in FIG. 6).

  Between the third outer cylinder 15 and the helicoid ring 18, there are provided three separation-direction biasing springs 25 for biasing each other in the separation direction in the optical axis direction. The separation-direction urging spring 25 is formed of a compression coil spring, and its rear end is housed in a spring insertion recess 18 f that opens to the front end of the helicoid ring 18, and its front end contacts the spring-attached recess 15 c of the third outer cylinder 15. In contact. Pressing the fitting projection 15b toward the front wall surface of the rotary sliding groove 22d and pressing the rotary sliding protrusion 18b toward the rear wall surface of the rotary sliding groove 22d by the separating direction urging spring 25. Thus, the backlash of the third outer cylinder 15 and the helicoid ring 18 with respect to the fixed ring 22 in the optical axis direction is eliminated.

  On the inner peripheral surface of the third outer cylinder 15, a claw-shaped relative rotation guide projection 15d protruding in the inner diameter direction, a circumferential groove 15e centered on the lens barrel center axis Z0, and a photographing optical axis Z1 are provided. Three parallel roller fitting grooves 15f are formed (FIGS. 4 and 11). A plurality of relative rotation guide protrusions 15d are provided at different positions in the circumferential direction. The roller fitting groove 15f is formed at a circumferential position corresponding to the rotation transmitting protrusion 15a, and a rear end portion thereof is opened rearward through the rotation transmitting protrusion 15a. A circumferential groove 18g centering on the lens barrel center axis Z0 is formed on the inner circumferential surface of the helicoid ring 18 (FIGS. 4 and 10). A straight guide ring 14 is supported inside the combined body of the third outer cylinder 15 and the helicoid ring 18. Three rectilinear guide protrusions 14a protruding in the radial direction are sequentially provided on the outer peripheral surface of the rectilinear guide ring 14 from the rear in the optical axis direction, and a plurality of claw-shaped relative rotation guides provided at different positions in the circumferential direction. Protrusions 14b and 14c and a circumferential groove 14d centered on the lens barrel center axis Z0 are formed (FIGS. 4 and 12). The linear guide ring 14 is guided linearly in the optical axis direction with respect to the fixed ring 22 by engaging the linear guide protrusion 14a with the linear guide groove 22b. Further, the third outer cylinder 15 engages the circumferential groove 15e with the relative rotation guide protrusion 14c and engages the relative rotation guide protrusion 15d with the circumferential groove 14d, so that the third outer cylinder 15 is It is rotatably connected. The circumferential groove 15e and the relative rotation guide protrusion 14c, and the circumferential groove 14d and the relative rotation guide protrusion 15d are each loosely fitted so as to be relatively movable in the optical axis direction. Further, the helicoid ring 18 is also relatively rotatably coupled to the rectilinear guide ring 14 by engaging the circumferential groove 18g with the relative rotation guide protrusion 14b. The circumferential groove 18g and the relative rotation guide protrusion 14b are loosely fitted so as to be able to relatively move relatively in the optical axis direction.

  The linear guide ring 14 is formed with three roller guide through grooves 14e penetrating the inner peripheral surface and the outer peripheral surface. As shown in FIG. 12, each of the roller guide through grooves 14e includes parallel front and rear circumferential grooves 14e-1 and 14e-2 formed in the circumferential direction, and both circumferential grooves 14e-1 and 14e-2. And a lead groove 14e-3 for connecting the A cam ring roller 32 provided on the outer peripheral surface of the cam ring 11 is fitted into each roller guide through groove 14e. The cam ring rollers 32 are fixed to the cam ring 11 via roller fixing screws 32a, and three cam ring rollers are provided at different positions in the circumferential direction. The cam ring roller 32 further penetrates the roller guide through groove 14e and is fitted in the roller fitting groove 15f on the inner peripheral surface of the third outer cylinder 15. Near the front end of each roller fitting groove 15f, three roller pressing pieces 17a provided on the roller urging spring 17 are fitted (FIG. 11). The roller pressing piece 17a comes into contact with the cam ring roller 32 and presses backward when the cam ring roller 32 engages with the circumferential groove portion 14e-1, and the cam ring roller 32 and the roller guide through groove 14e (in the circumferential direction). Backlash between the groove 14e-1) is removed.

  From the structure described above, the manner in which the fixed ring 22 extends from the cam ring 11 is understood. That is, when the zoom gear 28 is rotationally driven by the zoom motor 150 in the lens barrel extending direction, the helicoid ring 18 is extended forward while rotating due to the relationship between the female helicoid 22a and the male helicoid 18a. The helicoid ring 18 and the third outer cylinder 15 are relatively rotatable and rotatable with respect to the rectilinear guide ring 14 due to the engagement relationship between the circumferential grooves 14d, 15e and 18g and the relative rotation guide projections 15d, 14c and 14b, respectively. The third outer cylinder 15 is also extended forward while rotating in the same direction when the helicoid ring 18 is rotationally extended since the coupling is performed so as to move together in the axial direction (the direction along the lens barrel center axis Z0). Then, the straight guide ring 14 moves straight forward together with the helicoid ring 18 and the third outer cylinder 15. The rotational force of the third outer cylinder 15 is transmitted to the cam ring 11 via the roller fitting groove 15f and the cam ring roller 32. Since the cam ring roller 32 is also fitted into the roller guide through groove 14e, the cam ring 11 is extended forward with respect to the straight guide ring 14 while rotating according to the shape of the lead groove 14e-3. As described above, since the rectilinear guide ring 14 itself is also rectilinearly moving forward together with the third outer cylinder 15 and the helicoid ring 18, as a result, the cam ring 11 is provided with the rotation extension according to the lead groove 14e-3 and the rectilinear guide. The moving amount in the optical axis direction is given by adding the amount of forward movement of the ring 14 to the front.

  The above-described feeding operation is performed while the male helicoid 18a and the female helicoid 22a are screwed together, and at this time, the rotary sliding projection 18b moves in the oblique groove 22c. When the helicoid ring 18 and the third outer cylinder 15 are extended by a predetermined amount, the screw engagement between the male helicoid 18a and the female helicoid 22a is released, and the rotary sliding projection 18b and the fitting projection 15b are eventually rotated from the oblique groove 22c. It enters the moving groove 22d. Then, since the rotation repetition output by the helicoid does not work, the helicoid ring 18 and the third outer cylinder 15 are moved in the optical axis direction by the engagement relationship between the rotation sliding protrusion 18b and the fitting protrusion 15b and the rotation sliding groove 22d. Only rotation is performed at a fixed position. At substantially the same time when the rotary slide protrusion 18b enters the rotary slide groove 22d from the oblique groove 22c, the cam ring roller 32 enters the circumferential groove portion 14e-1 of the roller guide through groove 14e. Then, no forward moving force is applied to the cam ring 11, and the cam ring 11 only rotates at a fixed position according to the rotation of the third outer cylinder 15.

  When the zoom gear 28 is driven to rotate in the lens barrel housing direction, the reverse operation is performed. When the helicoid ring 18 is rotated until the cam ring roller 32 enters the circumferential groove 14e-2 of the roller guide through groove 14e, each of the above-mentioned lens barrel members is retracted to the position shown in FIG.

  Subsequently, the structure before the cam ring 11 will be described. On the inner peripheral surface of the rectilinear guide ring 14, three first rectilinear guide grooves 14f and six second rectilinear guide grooves 14g parallel to the photographing optical axis Z1 are formed at different positions in the circumferential direction. . The first rectilinear guide grooves 14f include a pair of grooves located on both sides of three of the six second rectilinear guide grooves 14g. The three crotch-shaped protrusions 10a (FIGS. 3 and 15) provided on the front panel are slidably engaged. On the other hand, the six rectilinear guide projections 13a (FIGS. 2 and 17) protruding from the outer peripheral surface of the rear end of the second outer cylinder 13 are slidably engaged with the second rectilinear guide grooves 14g. I have. Therefore, both the second outer cylinder 13 and the second group straight guide ring 10 are guided straight through the straight guide ring 14 in the optical axis direction.

  The second group straight guide ring 10 is a member for guiding the second group lens moving frame 8 that supports the second lens group LG2 straight, and the second outer cylinder 13 is a first outer cylinder that supports the first lens group LG1. It is a member for guiding the cylinder 12 straight.

  First, the support structure of the second lens group LG2 will be described. The second group straight guide ring 10 has three straight guide keys 10c protruding forward from a ring portion 10b connecting the three crotch-shaped protrusions 10a (FIGS. 3 and 15). As shown in FIGS. 6 and 7, the outer edge of the ring portion 10b can rotate relative to the circumferential groove 11e formed on the inner peripheral surface of the rear end of the cam ring 11, but cannot move relative to the optical axis. The straight guide key 10c is extended inside the cam ring 11. Each of the rectilinear guide keys 10 c has a pair of guide surfaces parallel to the photographing optical axis Z <b> 1, and the guide surfaces are formed by the rectilinear guide grooves of the second lens group moving frame 8 supported inside the cam ring 11. The second group lens moving frame 8 is guided linearly in the axial direction by engaging with the lens 8a. The rectilinear guide groove 8 a is formed on the outer peripheral surface side of the second group lens moving frame 8.

  The second group straight guide ring 10 is provided with three straight guide keys 10c at different positions in the circumferential direction, and one of the straight guide keys 10c-W is provided with an exposure control FPC (described later). In order to also serve as a support member for the flexible printed circuit (PCB) board 77, the width is circumferentially wider than the remaining two straight guide keys 10c. The wide straight guide key 10c-W is formed with an FPC through hole 10d which is partially cut away in the vicinity of the connection portion with the ring portion 10b and penetrates in the radial direction, and as shown in FIG. The board 77 extends from the rear of the ring portion 10b to the outer peripheral surface side of the linear guide key 10c-W through the FPC through hole 10d, and is bent rearward at the tip of the linear guide key 10c-W. Correspondingly, one of the three rectilinear guide grooves 8a is a wide rectilinear guide groove 8a-W to which the wide rectilinear guide key 10c-W can be engaged. A central portion of the straight guide groove 8a-W is a through portion through which the exposure control FPC board 77 can pass. A bottom portion for supporting the straight guide key 10c-W is provided on both sides of the through portion. Is formed. On the other hand, the remaining two rectilinear guide grooves 8 a are both bottomed grooves formed on the outer peripheral surface side of the second group lens moving frame 8. The second group lens moving frame 8 and the second group straight guide ring 10 can be combined only in a specific rotation phase in which the straight guide keys 10c-W can engage with the straight guide grooves 8a-W.

  A second group guide cam groove 11 a is formed on the inner peripheral surface of the cam ring 11. As shown in FIG. 14, the second group guide cam groove 11a includes a front cam groove 11a-1 and a rear cam groove 11a-2 whose positions are different in the optical axis direction and the circumferential direction. Each of the front cam groove 11a-1 and the rear cam groove 11a-2 is a cam groove formed by tracing the same base locus α, but does not cover the entire area of the base locus α. The front cam groove 11a-1 and the rear cam groove 11a-2 differ from each other in a part of the area occupied on the basic locus α. The basic trajectory is a conceptual cam groove shape including all the lens barrel use areas (use areas) including the zoom area and the storage area, and the lens barrel assembly / disassembly area. That is, the lens barrel use area is an area in which the movement of the second lens group moving frame 8 can be controlled by the cam groove shape, and is used to distinguish it from the assembly and disassembly area. Further, the zoom area is an area for controlling movement between the wide end and the tele end particularly in the lens barrel use area, and is used to distinguish it from the storage area. When a pair of the front cam groove 11a-1 and the rear cam groove 11a-2 are formed as one group, the cam ring 11 is formed with three groups of second group guide cam grooves 11a at equal intervals in the circumferential direction.

  The second group cam follower 8b provided on the outer peripheral surface of the second group lens moving frame 8 is engaged with the second group guide cam groove 11a. Similarly to the second group guide cam groove 11a, the second group cam followers 8b are also circumferentially equally spaced as a group of a pair of front cam followers 8b-1 and rear cam followers 8b-2 whose positions are different in the optical axis direction and the circumferential direction. The front cam followers 8b-1 engage with the front cam grooves 11a-1, and the rear cam followers 8b-2 engage with the rear cam grooves 11a-2 in the optical axis direction. A circumferential interval is defined.

  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 is driven in accordance with the second group guide cam groove 11a. It moves along a predetermined trajectory in the axial direction.

  Inside the second group lens moving frame 8, a second group lens frame 6 that holds the second lens group LG2 is supported. The second group lens frame 6 is supported by a pair of second group lens frame support plates 36 and 37 via a second group rotation shaft 33, and the second group frame support plates 36 and 37 are supported plate fixing screws 66. To the second group lens moving frame 8. The second-group rotation axis 33 is parallel to the imaging optical axis Z1 and is eccentric with respect to the imaging optical axis Z1, and the second-group lens frame 6 has the second lens group LG2 with the second-group rotation axis 33 as the rotation center. A photographing position (FIG. 6) where the optical axis of the second lens group LG2 coincides with the photographing optical axis Z1, and a retracting position (FIG. 6) for displacing the optical axis of the second lens group LG2 from the photographing optical axis Z1 to the retracted optical axis Z2. 7). The second group lens moving frame 8 is provided with a rotation restricting pin 35 for restricting the second group lens frame 6 from rotating at the photographing position. The second group lens frame 6 is moved by a second group lens frame returning spring 39. It is urged to rotate in the direction of contact with the rotation restricting pin 35. The axial pressing spring 38 performs backlash removal of the second lens group frame 6 in the optical axis direction.

  The second group lens frame 6 moves integrally with the second group lens moving frame 8 in the optical axis direction. A cam projection 21a (FIG. 4) projects forward from the CCD holder 21 at a position where it can be engaged with the second group lens frame 6. As shown in FIG. When it moves and approaches the CCD holder 21, the cam surface formed at the tip of the cam projection 21a engages with the second lens group frame 6 and rotates to the above-mentioned retracted position for storage.

  Subsequently, a support structure of the first lens group LG1 will be described. On the inner peripheral surface of the second outer cylinder 13 guided straight in the optical axis direction via the straight guide ring 14, three rectilinear guide grooves 13b are formed in the optical axis direction at positions different in the circumferential direction. The three engagement projections 12a formed on the outer peripheral surface near the rear end of the first outer cylinder 12 are slidably fitted into the respective linear guide grooves 13b (FIGS. 2, 17, and 18). reference). That is, the first outer cylinder 12 is guided linearly in the optical axis direction via the straight guide ring 14 and the second outer cylinder 13. The second outer cylinder 13 has an inner peripheral flange 13c on the inner peripheral surface in the vicinity of the rear end thereof, and the inner peripheral flange 13c slides in a circumferential groove 11c provided on the outer peripheral surface of the cam ring 11. By engaging as much as possible, the second outer cylinder 13 is coupled to the cam ring 11 so as to be rotatable relative to the cam ring 11 and not to move relative to the optical axis. On the other hand, the first outer cylinder 12 has three first group rollers (cam followers) 31 protruding in the inner diameter direction, and each first group roller 31 is formed on the outer peripheral surface of the cam ring 11 as one group. It is slidably fitted in the guide cam groove 11b.

  The first lens barrel 1 is supported in the first outer cylinder 12 via a first lens adjusting ring 2. The first lens group LG1 is fixed to the first group lens frame 1, and a male adjustment screw 1a formed on the outer peripheral surface thereof is screwed with a female adjustment screw 2a formed on the inner peripheral surface of the first group adjustment ring 2. . By adjusting the screw position of the adjusting screw, the position of the first lens group frame 1 with respect to the first lens group adjusting ring 2 can be adjusted in the optical axis direction.

  The first group adjusting ring 2 has a pair of (only one is shown in FIG. 2) guide protrusions 2 b protruding in the outer diameter direction, and the pair of guide protrusions 2 b are formed on the inner peripheral surface side of the first outer cylinder 12. Are slidably engaged with the pair of first group adjusting ring guide grooves 12b formed in the first group. The first group adjustment ring guide groove 12b is formed in parallel with the photographing optical axis Z1, and the first group adjustment ring 2 and the first group lens frame 1 are formed by the engagement relationship between the first group adjustment ring guide groove 12b and the guide projection 2b. The combined body can be moved back and forth in the optical axis direction with respect to the first outer cylinder 12. The first group retaining ring 3 is further fixed to the first outer cylinder 12 with a retaining ring fixing screw 64 so as to close the front of the guide protrusion 2b. A first-group urging spring 24 composed of a compression coil spring is provided between the spring receiving portion 3a of the first-group retaining ring 3 and the guide protrusion 2b. It is biased rearward in the axial direction. The first group adjusting ring 2 is formed by engaging an engaging claw 2c protruding from an outer peripheral surface near a front end portion thereof with a front surface (a surface visible in FIG. 2) of the first group retaining ring 3. The maximum movement position in the optical axis direction rearward relative to the one outer cylinder 12 is regulated (see the upper half section in FIG. 6). On the other hand, by compressing the first-group urging spring 24, the first-group adjusting ring 2 can move a little forward in the optical axis direction.

  A shutter unit 76 having a shutter S and an aperture A is supported between the first lens group LG1 and the second lens group LG2. The shutter unit 76 is supported inside the second-group lens moving frame 8, and the shutter S and the aperture A have a fixed air gap between the second lens group LG2. Two actuators 131 and 132 (FIG. 19) for driving the shutter S and the aperture A are respectively arranged at front and rear positions with the shutter unit 76 interposed therebetween. An exposure control FPC board 77 for connecting to the control circuit 140 extends. The exposure control FPC board 77 does not actually exist at the position of the lower half section (wide end) in FIG. 6, but is shown for easy understanding of the positional relationship with other members.

  In addition to the shutter S, a lens barrier mechanism is provided at the front end of the first outer cylinder 12 for closing the photographing aperture when not photographing to protect the photographing optical system (first lens group LG1). The lens barrier mechanism includes a pair of barrier blades 104 and 105 rotatable about a rotation axis provided at a position eccentric to the lens barrel center axis Z0, and biases the barrier blades 104 and 105 in a closing direction. A pair of barrier urging springs 106, a barrier drive ring 103 that is rotatable about a lens barrel center axis Z0 and engages and opens the barrier blades 104, 105 by rotation in a predetermined direction, and the barrier drive ring. A barrier drive ring biasing spring 107 for biasing the rotary shaft 103 in the barrier opening direction is provided, and a barrier pressing plate 102 located between the barrier blades 104 and 105 and the barrier drive ring 103. The urging force of the barrier driving ring urging spring 107 is set stronger than the urging force of the barrier urging spring 106, and when the zoom lens barrel 71 is extended to the zoom region (FIG. 6), the barrier driving ring urging spring 107 is turned on. The biasing spring 107 holds the barrier drive ring 103 at the barrier opening angular position, and the barrier blades 104 and 105 are opened against the barrier biasing spring 106. Then, while the zoom lens barrel 71 is moving from the zoom region to the storage position (FIG. 7), the barrier drive ring pressing surface 11d (FIGS. 3 and 13) of the cam ring 11 causes the barrier drive ring 103 to be opposed to the barrier opening direction. The barrier drive ring 103 is disengaged from the barrier blades 104 and 105 by being forcedly rotated in the direction, and the barrier blades 104 and 105 are closed by the urging force of the barrier urging spring 106. The front of the lens barrier mechanism is covered by a barrier cover 101 (decorative plate).

  The entire extension and storage operation of the zoom lens barrel 71 having the above structure will be described with reference to FIGS. 6, 7, and 19. FIG. FIG. 19 conceptually shows the relationship between the main members of the zoom lens barrel 71, where "S" in parentheses after the reference numeral of each member is a fixed member, and "L" is an optical axis direction. A member that performs only linear movement, “R” means a member that performs only rotation, and “RL” means a member that moves in the optical axis direction while rotating. A member in which two symbols are written in parentheses means that the operation mode is switched at the time of feeding and storage.

  The steps up to the stage in which the cam ring 11 is extended from the storage position to the home position rotation state have already been described, and thus will be briefly described. 7, the zoom lens barrel 71 is completely stored in the camera body 72, and the front surface of the camera 70 has a flat shape in which the zoom lens barrel 71 does not protrude from the camera body 72. I have. When the zoom gear 28 is rotationally driven in the extension direction by the zoom motor 150 from the lens barrel stored state, the combined body of the helicoid ring 18 and the third outer cylinder 15 is rotated and extended in accordance with the helicoid (the male helicoid 18a and the female helicoid 22a). The straight guide ring 14 moves straight forward together with the third outer cylinder 15 and the helicoid ring 18. At this time, the cam ring 11 to which the rotational force is applied by the third outer cylinder 15 has a lead structure (a cam ring roller) provided between the linear guide ring 14 and the linear movement forward. 32, the combined movement with the extended portion by the lead groove portion 14e-3) is performed. When the helicoid ring 18 and the cam ring 11 are extended to a predetermined position in front, the functions of the respective rotating and extending structures (helicoid, lead) are released, and only the circumferential rotation about the lens barrel center axis Z0 is performed. become.

  When the cam ring 11 rotates, the second-group lens moving frame 8 guided straight through the second-group straight guide ring 10 is rotated in the optical axis direction by the relationship between the second-group cam follower 8b and the second-group guide cam groove 11a. Is moved along a predetermined locus. In the lens barrel storage state of FIG. 7, the second group lens frame 6 in the second group lens moving frame 8 is a storage retracting position eccentric upward from the photographing optical axis Z1 by the action of the cam projection 21a protruding from the CCD holder 21. And the second lens group LG2 is located at the retracted optical axis Z2. The second group lens frame 6 separates from the cam projection 21a while the second group lens moving frame 8 is being extended to the zoom region, and is biased by the second group lens frame return spring 39 to move the optical axis of the second lens group LG2. Is rotated to a photographing position (FIG. 6) where the image coincides with the photographing optical axis Z1. Thereafter, the second group lens frame 6 is held at the photographing position until the zoom lens barrel 71 is moved to the storage position again.

  When the cam ring 11 rotates, outside the cam ring 11, the first outer cylinder 12, which is guided straight through the second outer cylinder 13, has a relationship between the first group roller 31 and the first group guide cam groove 11 b. Is moved along a predetermined locus in the optical axis direction.

  That is, the extension positions of the first lens group LG1 and the second lens group LG2 with respect to the image pickup surface (CCD light receiving surface) are determined by the amount of forward movement of the cam ring 11 with respect to the fixed ring 22 and the first The latter is determined as the sum of the cam extension of the outer cylinder 12 and the latter is the sum of the forward movement of the cam ring 11 with respect to the fixed ring 22 and the cam extension of the second lens unit moving frame 8 with respect to the cam ring 11. Decided. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 on the photographing optical axis Z1 while changing the air gap between them. When the lens barrel is extended from the storage position of FIG. 7, the wide end is first extended as shown in the lower half section of FIG. 6, and when the zoom motor 150 is further driven in the lens barrel extending direction, the upper half section of FIG. As shown in FIG. As can be seen from FIG. 6, the zoom lens barrel 71 of the present embodiment has a large distance between the first lens group LG1 and the second lens group LG2 at the wide end, and a large distance between the first lens group LG1 and the second lens at the telephoto end. The group LG2 moves in the approaching direction of each other, and the interval decreases. Such a change in the air gap between the first lens group LG1 and the second lens group LG2 is given by the locus of the second group guide cam groove 11a and the first group guide cam groove 11b. In the zoom region (zooming use region) between the tele end and the wide end, the cam ring 11, the third outer cylinder 15, and the helicoid ring 18 perform only the above-described fixed position rotation, and do not advance or retreat in the optical axis direction.

  In the zoom region, by driving the AF motor 160 according to the subject distance, the third lens group LG3 (AF lens frame 51) moves along the photographing optical axis Z1 to perform focusing.

  When the zoom motor 150 is driven in the lens barrel storage direction, the zoom lens barrel 71 performs a storage operation reverse to that at the time of the above-described extension, and is stored in the camera body 72 completely (FIG. 7). Moved to During the movement to the storage position, the second group lens frame 6 is rotated to the storage retracting position by the cam projection 21a, and retracts together with the second group lens movement frame 8. When the zoom lens barrel 71 is moved to the storage position, the second lens group LG2 is stored at the same position in the optical axis direction as the third lens group LG3 and the low-pass filter LG4 (overlaps in the radial direction of the barrel). . The retracted structure of the second lens group LG2 during storage makes it possible to shorten the storage length of the zoom lens barrel 71 and reduce the thickness of the camera body 72 in the left-right direction in FIG.

  The digital camera 70 includes a zoom finder linked to the zoom lens barrel 71. The zoom finder obtains power from the helicoid ring 18 by meshing the finder gear 30 with the spur gear portion 18c. When the helicoid ring 18 performs the above-described fixed position rotation in the zoom region, the finder gear receives the rotational force and receives the power. 30 rotates. The finder optical system has an objective window 81a, a first movable variable power lens 81b, a second movable variable power lens 81c, a prism 81d, an eyepiece 81e, and an eyepiece window 81f, and has first and second movable variable power. Zooming is performed by moving the lenses 81b and 81c along a predetermined locus along the optical axis Z3 of the finder objective system. The optical axis Z3 of the finder objective system is parallel to the photographing optical axis Z1. The holding frames 83 and 84 of the movable variable power lenses 81b and 81c are guided by guide shafts 85 and 86 (see FIGS. 6 and 7 so as to overlap and appear as one) so as to be movable in the direction of the optical axis Z3, and The moving force is given by a cam gear 90 (FIG. 5) rotatable about a rotation center axis parallel to the optical axis Z3. A reduction gear train is provided between the cam gear 90 and the finder gear 30. When the finder gear 30 rotates, the cam gear 90 is rotated, and as a result, the movable zoom lenses 81b and 81c move forward and backward. The above components of the zoom finder are sub-assembled as a finder unit 80 shown in FIG.

[Description of Characteristic Features of the Present Invention]
The cam ring 11 and the first outer cylinder (movable member, movable ring) 12 are arranged concentrically about the lens barrel center axis Z0, and the first outer cylinder 12 is for one group projecting in the inner diameter direction thereof. The roller (cam follower) 31 and the first group guide cam groove 11b formed on the outer peripheral surface of the cam ring 11 are moved along a predetermined locus in the optical axis direction by an engagement relationship. The relationship between the first group roller 31 and the first group guide cam groove 11b is shown in a developed view in FIGS. 20 to 30, the first outer cylinder 12 is represented by a dashed line, and the second outer cylinder 13 is represented by a two-dot chain line.

  As shown in FIG. 13, the first group guide cam groove 11 b formed on the outer peripheral surface of the cam ring 11 has one end portion as a front open area 11 b-X opening to the front end surface of the cam ring 11, and the other end portion having a cam. A so-called open both end cam groove is formed as a rear open area (open end, photographing standby area, storage area) 11b-Y that opens to the rear end face of the ring 11. The first group guide cam groove 11b is located at a position between the inclined open area 11b-L and the open front area 11b-X. And a chevron region 11b-Z. The zoom region (photographing control region) used for photographing in the first group guide cam groove 11b is included in the chevron region 11b-Z.

  As shown in FIGS. 24 and 30, the first-group roller 31 is incorporated into the first-group guide cam groove 11b through the front open area 11b-X, and is also pulled forward through the front open area 11b-X when detached. The first-group roller 31 is located near the front open area 11b-X in the chevron area 11b-Z at the telephoto end (FIGS. 23 and 29), and has the inclined lead in the chevron area 11b-Z at the wide end. It is located near the region 11b-L (FIGS. 22 and 28).

  20 and 25, the first group roller 31 moves into the rear open area 11b-Y. The rear open area 11b-Y is wider in the circumferential direction than the inclined lead area 11b-L and the chevron area 11b-Z, and in the rear open area 11b-Y, the movement of the first group roller 31 in the circumferential direction is restricted. Permissible. The rear open area 11b-Y is open to the rear end face side of the cam ring 11, but is separate from the first group roller 31 and the first group guide cam groove 11b. A movement restricting portion for restricting relative movement of the first group is provided so that the first group roller 31 does not fall rearward from the rear open area 11b-Y.

  That is, as shown in FIG. 13, the cam ring 11 has a front protruding portion 11f protruding forward in the optical axis direction and an outer diameter protruding in the outer diameter direction from the outer peripheral surface where the first group guide cam groove 11b is formed. Three protrusions 11g are provided at different positions in the circumferential direction. The outer diameter protruding portion 11g is a convex portion provided with the above-described circumferential groove 11c and the cam ring roller 32 on the outer peripheral surface thereof. The front protruding portion 11f and the outer diameter protruding portion 11g are respectively formed by a front stopper surface (movement restricting portion) 11s-1 and a rear stopper surface (movement restricting portion) formed in a plane orthogonal to the optical axis Z1 of the photographing optical system. ) 11s-2. On the other hand, as shown in FIG. 18, three front stopper surfaces (movement restricting portions) 12s-1 are formed on the inner peripheral surface of the first outer cylinder 12 as projections projecting in the inner diameter direction. The surface 12s-1 faces the front stopper surface 11s-1 on the cam ring 11 side. Further, on the rear end side of the first outer cylinder 12, three rear stopper surfaces (movement restricting portions) 12s-2 facing the rear stopper surface 11s-2 on the cam ring 11 side are formed. The front and rear stopper surfaces 12s-1 and 12s-2 of the first outer cylinder 12 are surfaces parallel to the front and rear stopper surfaces 11s-1 and 11s-2 on the cam ring side, respectively. The distance between the front stopper surface 11s-1 and the rear stopper surface 11s-2 in the cam ring 11 in the optical axis direction is the same as the distance between the front stopper surface 12s-1 and the rear stopper surface 12s-2 of the first outer cylinder 12 in the optical axis direction. Equal to the interval.

  In the lens barrel retracted state, as shown in FIGS. 20 and 25, the front stopper surface 12s-1 comes close to the vicinity of the front stopper surface 11s-1, and at the same time, the rear stopper surface 12s-2 becomes closer to the rear stopper surface 11s-2. The first outer cylinder 12 is restricted from moving rearward from the illustrated position by the respective stopper surfaces. Since the rear is the same as the opening direction of the rear opening area 11b-Y in the first group guide cam groove 11b (indicated by the arrow J in FIGS. 13, 20, and 25), it is located in the rear opening area 11b-Y. The first group roller 31 does not move further in the opening direction of the rear opening area 11b-Y, and is prevented from being separated from the rear opening area 11b-Y. In other words, the stopper surfaces 12s-1, 11s-1, 11s-2, and 12s-2 are located behind the first outer cylinder 12 with respect to the cam ring 11 when the zoom lens barrel 71 is housed (the rear open area 11b). (Opening direction of -Y) Functions as a movement restricting unit that determines the moving end.

  In the present embodiment, since the rear open area 11b-Y is formed to be wide, the first outer cylinder 12 is closed when the first group roller 31 enters the rear open area 11b-Y during the lens barrel storing operation. The moving force in the optical axis direction with respect to is stopped, and the retreating movement of the first outer cylinder 12 stops immediately before the stopper surfaces come into contact with each other. At this time, the interval between the front stopper surfaces 11s-1 and 12s-1 and the interval between the rear stopper surfaces 11s-2 and 12s-2 are each set to 0.1 mm. However, the first outer cylinder 12 may be retracted to a position where the front stopper surfaces 11s-1, 12s-1 and the rear stopper surfaces 11s-2, 12s-2 come into contact with each other by inertia.

  Further, an inner diameter flange 12c having a first group adjusting ring guide groove 12b (see FIG. 2) is formed on the inner peripheral surface of the first outer cylinder 12, and the front stopper surface 12s-1 is located forward of the inner diameter flange 12c. It is located in. The inner diameter flange 12c is formed with a flange opening 12d through which the front protruding portion 11f of the cam ring 11 can pass. When the front stopper 11 surface 11s-1 approaches the front stopper surface 12s-1, the front protruding portion is formed. 11f enters into the flange opening 12d.

  In this embodiment, the cam ring 11 and the first outer cylinder 12 are provided with two stopper surfaces (11s-1, 11s-2, 12s-1 and 12s-2) at different positions in the front-rear direction. However, since it is possible to restrict the movement of the first outer cylinder 12 if there is at least one stopper portion, for example, an embodiment in which only one of the front and rear stopper surfaces of the embodiment is used is also possible. . Conversely, more stoppers may be used than in the embodiment. For example, although not used in the present embodiment, three front end surfaces 11h located between the front protruding portions 11f on the cam ring 11 and the flange rear surface 12e of the inner diameter flange 12c of the first outer cylinder 12 are in contact with each other. It is also possible to restrict the movement of the first outer cylinder 12 by making contact with the first outer cylinder 12.

  In the first group guide cam groove 11b, the area excluding the front open area 11b-X for assembling and disassembling, that is, from the storage position of the first group roller 31 (rear open area 11b-Y) in FIGS. The area up to the tele end position of the first group roller 31 in FIG. 29 is a use area used at the time of zoom operation and storage. By making the rear open area 11b-Y, which is one end of this use area, an open part to the rear of the cam ring 11, the thickness (wall surface) for closing the cam groove behind the rear open area 11b-Y is reduced. This is unnecessary, and accordingly, the cam ring 11 can be downsized in the optical axis direction. That is, in the cam groove of the conventional concept, the end of the use area (if there is an open end for assembling the cam follower, the opposite end) should be closed. Although a predetermined thickness is required before the end portion, according to the structure of the present embodiment in which this thickness is not required, the size of the cam ring can be reduced accordingly.

  An open portion such as the rear open area 11b-Y can be formed while being a use area in the cam groove, because the first group guide cam groove 11b and the first group roller 31 are provided separately. This is because the limit position of the rearward movement of the first outer cylinder 12 with respect to the cam ring 11 is separately determined by the stopper surfaces (11s-1, 11s-2, 12s-1 and 12s-2). By providing such a movement restricting portion that functions separately from the first group guide cam groove 11b and the first group roller 31, the first group roller 31 can drop off from the rear open area 11b-Y and be engaged again. There is no danger of disappearing.

  When the first-group roller 31 is located in the rear open area 11b-Y, the lens barrel is stored, that is, no photographing is performed, and strict positional accuracy of the optical element is not required unlike the photographing state. . Therefore, there is no practical problem if the rear open area 11b-Y is formed as a wide open end to loosen the engagement with the first group roller 31. Conversely, the storage area where the loose fit with the first group roller 31 is allowed is set at the end of the first group guide cam groove 11b, and the end of the cam groove is set. By setting the trajectory of the entire first group guide cam groove 11b such that the portion is located at the rearmost position in the optical axis direction, it becomes possible to make the storage area an open end like the rear open area 11b-Y. Was.

  When the first outer cylinder 12 is extended from the stowed state to the zoom area (capturable position), the first group roller 31 loosely fitted in the rear open area 11b-Y is securely moved into the inclined lead area 11b-L. To this end, three lead slopes 11t and 12t are formed on the cam ring 11 and the first outer cylinder 12 at different positions in the circumferential direction. The lead slope 11t of the cam ring 11 is formed on the front protruding portion 11f as a slope continuous with the above-described front stopper surface 11s-1. The first outer cylinder 12 is provided with three triangular rear projecting portions 12f having engaging projections 12a on the outer peripheral surface at different positions in the circumferential direction, and the lead slope 12t is formed in the triangular rear projecting portion. It is formed as one side of the portion 12f. As shown in FIG. 25 to FIG. 30, each lead slope 11t, 12t is a plane parallel to the sloped lead area 11b-L of the first group guide cam groove 11b.

  20 and 25, the edge portion ED1 of the inner diameter flange 12c of the first outer cylinder 12 is opposed to the lead slope 11t of the cam ring 11. The edge portion ED2 of the outer diameter protruding portion 11g of the cam ring 11 is opposed to the lead slope 12t of the first outer cylinder 12. 20 and 25, the edge portions ED1 and ED2 are slightly separated from the lead slopes 11t and 12t. When the cam ring 11 rotates in the feeding direction (the upward direction in FIGS. 21 and 26), the first group roller 31 is moved in the rear open area 11b-Y in the initial stage of rotation (between FIGS. 25 and 26). Are moved only in the circumferential direction, and as shown in FIGS. 21 and 26, the lead slope 11t approaches the edge ED1, and the lead slope 12t approaches the edge ED2. In this state, no moving force acts on the first outer cylinder 12 in the optical axis direction.

  In the state shown in FIGS. 21 and 26 in which the lead slopes 11t and 12t are very close to the edge parts ED1 and ED2, respectively, the first group roller 31 has reached the entrance of the inclined lead area 11b-L. Here, when the rotation of the cam ring 11 in the feeding direction is continued, the first group roller 31 comes into contact with one side surface of the inclined lead region 11b-L and enters the inclined lead region 11b-L. At this time, each of the edge portions ED1 and ED2 and each of the lead slopes 11t and 12t function as an auxiliary portion for allowing the first group roller 31 to enter the inclined lead region 11b-L. That is, when the cam ring 11 rotates in the extending direction with the edge portion ED1 abutting on the lead slope 11t and the edge portion ED2 abutting on the lead slope 12t, the edge portions ED1, ED2 move on the lead slopes 11t, 12t. The first outer cylinder 12 slides and is pressed and moved forward with respect to the cam ring 11 along a locus along the lead slopes 11t and 12t. Since the lead slopes 11t and 12t are parallel to the slanted lead area 11b-L of the cam groove 11b, the moving force applied to the first outer cylinder 12 causes the first group roller 31 to move from the rear open area 11b-Y to the slanted lead. It acts so as to enter the area 11b-L. In terms of design, the first group roller 31 is brought into contact with one side surface of the inclined lead region 11b-L before the edge portions ED1 and ED2 come into contact with the lead inclined surfaces 11t and 12t. The first group roller 31 may be drawn into the oblique lead region 11b-L depending on the shape of itself. Even in this case, it is preferable to provide auxiliary parts such as the edge parts ED1 and ED2 and the lead slopes 11t and 12t. For example, even if the positional relationship between the first group roller 31 and the inclined lead area 11b-L in the housed state slightly shifts due to backlash between members, etc., each edge portion ED1, The first group roller 31 can be reliably guided into the inclined lead area 11b-L by engaging the ED 2 with each of the lead slopes 11t and 12t. In any case, after the first-group roller 31 has completely entered the inclined lead area 11b-L, as shown in FIG. 27, the engagement between the lead slopes 11t, 12t and the edge portions ED1, ED2 may cause a problem. Instead, the first outer cylinder 12 can be moved in the optical axis direction only by the relationship between the first group roller 31 and the first group guide cam groove 11b.

  As described above, in the lens barrel extending operation from the stowed state, the lead slopes 11t, 12t and the edge portions function substantially in the same manner as the inclined lead area 11b-L of the first group guide cam groove 11b and the first group roller 31. By providing the ED1 and ED2, even when the first-group roller 31 is loosely fitted in the rear open area 11b-Y, the first-group roller 31 is moved into the inclined lead area 11b-L ( It is possible to reliably enter the chevron region 11b-Z) and there is no possibility of malfunction.

  In this embodiment, both the cam ring 11 and the first outer cylinder 12 are provided with the lead slopes 11t and 12t. However, the lead slope is provided only in the cam ring 11 or the first outer cylinder 12. Is also good. Alternatively, it is possible to provide more lead slopes than in the embodiment.

  A different embodiment of the present invention is shown in FIG. FIG. 31 shows the lens barrel stored state corresponding to FIG. 25 of the previous embodiment, and a description of members and parts that function similarly to FIG. 25 will be omitted.

  The first group guide cam groove 11b 'of the cam ring 11' in FIG. 31 does not have an area corresponding to the rear open area 11b-Y in FIG. 25, and the end of the inclined lead area 11b-L 'is An open end 11b-K is formed at the rear end of the ring 11 '. The first group roller 31 'moves rearward (in the right-hand direction in FIG. 31) in the inclined lead area 11b-L' when the lens barrel housing operation from the wide end is performed. It passes through the open end 11b-K and comes off the first group guide cam groove 11b '. When the first group roller 31 'comes off the first group guide cam groove 11b', no moving force in the optical axis direction acts on the first outer cylinder 12 ', so the first outer cylinder 12' stops. I do. At this time, the front stopper surface 12s-1 'and the rear stopper surface 12s-2' formed on the first outer cylinder 12 'respectively correspond to the front stopper surface 11s-1' formed on the front protruding portion 11f 'of the cam ring 11'. To the rear stopper surface 11s-2 'formed on the outer diameter projecting portion 11g', the first outer cylinder 12 'is further restricted from moving backward. As in the previous embodiment, the rear direction is the same as the opening direction of the lead area open end 11b-K in the first group guide cam groove 11b '(indicated by an arrow J' in FIG. 31). Even if the roller 31 'separates from the first group guide cam groove 11b', there is no possibility that the first outer cylinder 12 'moves indefinitely in the direction away from the lead area open end 11b-K. In other words, each of the stopper surfaces 12s-1 ', 11s-1', 11s-2 'and 12s-2' is a rearward moving end of the first outer cylinder 12 'with respect to the cam ring 11' in the lens barrel housed state. It functions as a movement restricting portion that determines the open end 11b-K of the lead area in the opening direction. As in the previous embodiment, when the lens barrel is stored, it is desirable that the front and rear stopper surfaces of the cam ring 11 'and the first outer cylinder 12' face each other with a clearance of about 0.1 mm. The first outer cylinder 12 'may be retracted by inertia to a position where the front stopper surfaces 11s-1' and 12s-1 'and the rear stopper surfaces 11s-2' and 12s-2 'come into contact.

  When the first group roller 31 'is separated from the first group guide cam groove 11b' in the lens barrel storage state (photographing standby state), the storage area of the first group roller 31 'in this state is one group guide. Since it can be omitted from the cam groove 11b ', the size of the cam ring 11' can be further reduced.

  In this embodiment, since the first-group roller 31 'has a structure in which the first-group guide cam groove 11b' is detached, the first-group roller 31 'is re-fitted into the first-group guide cam groove 11b' at the next extension of the lens barrel. It is particularly effective to provide an entry assisting part for matching. In the retracted state of FIG. 31, the edge portion ED1 'of the inner diameter flange 12c' of the first outer cylinder 12 'comes into contact with the lead slope 11t' formed on the front protruding portion 11f 'of the cam ring 11', and The edge portion D2 'of the outer diameter protruding portion 11g' of the cam ring 11 'is in contact with the lead slope 12t' formed on the rear protruding portion 12f 'of the outer cylinder 12'. Each of the lead slopes 11t 'and 12t' is a slope parallel to the sloped lead area 11b-L '. Therefore, when the cam ring 11 'is rotated in the extending direction from the stored state, the first outer cylinder 12' is pressed forward in the optical axis direction, and the first group roller 31 which has been separated from the first group guide cam groove 11b '. Enters the inclined lead area 11b-L 'through the lead area open end 11b-K. After that, the first group roller 31 'moves in the first group guide cam groove 11b' in accordance with the rotation of the cam ring 11 'in the feeding direction, and the chevron area 11b-Z' is formed as in the previous embodiment. Zooming, and the first group roller 31 'can be moved to the front open area 11b-X' to be disassembled.

  As described above, according to the structure of the present embodiment, even when the first group roller 31 'is disengaged from the first group guide cam groove 11b' when the lens barrel is stored, the movement limit of the first outer cylinder 12 in the storing direction is limited. The position can be reliably determined, and the first-group roller 31 'can reliably enter the first-group guide cam groove 11b' at the time of feeding.

  As can be seen from the above description of the embodiment, in the advance / retreat cam mechanism of the present invention, the cam follower (in the housed state of the lens barrel in which the strict guide by the cam grooves (first group guide cam grooves 11b, 11b ') is not required). The first group rollers 31, 31 ') are positioned within the open ends of the cam grooves (rear open areas 11b-Y) or are separated from the open ends of the cam grooves (lead area open ends 11b-K). Further, by providing a movement restricting portion (each stopper surface 11s-1 ('), 11s-2 ('), 12s-1 ('), 12s-2 (')), a movable member having a cam follower (the 1 outer cylinder 12, 12 ') is prevented from falling off (unlimited movement). As a result, the size of the cam ring for moving the movable member can be reduced as compared with the related art.

  However, the present invention is not limited to the embodiment. For example, in the embodiment, the cam ring 11 is a rotation advance / retreat ring that moves in the optical axis direction while rotating from the storage position to the zoom range. However, in the present invention, the cam ring does not advance / retreat in the rotation axis direction. The present invention can also be applied to a type of forward / backward cam mechanism that always rotates at a fixed position.

  Further, in the embodiment, each stopper surface is formed as a movement restricting portion on the cam ring 11 and the first outer cylinder 12, but the combination of the members providing the movement restricting portion is a movable member having a cam follower and a cam having a cam groove. It is not limited to a ring. For example, when the cam ring does not advance or retreat in the rotation axis direction as described above, the same effect can be obtained even if the movement restricting portion is formed on a fixed member other than the cam ring.

  Further, the first group guide cam groove 11b (11b ') of the embodiment has both ends opened to the front and rear ends of the cam ring 11 (11'), so that the front front open area 11b-X (11b-X ') is one. The rear opening area 11b-Y (11b-Y ') is used as a part of the use area as the opening for inserting and removing the group roller 31 (31'), but the workability of assembling the lens barrel is not considered. In this case, the front open area 11b-X (11b-X ') is inserted and removed from the rear open area 11b-Y or the lead area open end 11b-K side. It is also possible to omit it.

In the embodiment, a first group guide cam groove 11b (11b ') is formed on the outer peripheral surface of the cam ring 11 (11'), and the first group guide cam groove 11b (11b ') is formed from the outer diameter side of the lens barrel with respect to the first group guide cam groove 11b (11b'). Although the first group roller 31 (31 ') is engaged, in the present invention, a cam groove is formed on the inner peripheral surface of the cam ring, and the cam follower is engaged with the cam groove from the lens barrel inner diameter side. It is also applicable to a type of forward / backward cam mechanism.

FIG. 1 is an exploded perspective view of a zoom lens barrel to which the present invention is applied. FIG. 2 is an exploded perspective view of elements related to a support mechanism of a first lens group in the zoom lens barrel in FIG. 1. FIG. 2 is an exploded perspective view of elements related to a support mechanism of a second lens group in the zoom lens barrel in FIG. 1. FIG. 2 is an exploded perspective view of elements related to a feeding mechanism from a fixed ring to a third outer cylinder in the zoom lens barrel in FIG. 1. FIG. 2 is a perspective view of a completed state in which a zoom motor and a finder unit are added to the zoom lens barrel of FIG. 1. FIG. 2 is a longitudinal sectional view showing a use state of a camera equipped with a zoom lens barrel to which the present invention is applied, at a wide end and a telephoto end. FIG. 3 is a longitudinal sectional view of the camera in a lens barrel stored state. FIG. 4 is a developed plan view of a fixed ring. FIG. 3 is a developed plan view of a helicoid ring. FIG. 3 is an exploded plan view showing components on the inner peripheral surface side of the helicoid ring in a see-through manner. It is a development top view of the 3rd outer cylinder. FIG. 4 is a developed plan view of a straight guide ring. FIG. 4 is a developed plan view of a cam ring. FIG. 7 is an exploded plan view showing the second group guide cam groove on the inner peripheral surface side of the cam ring in a see-through manner. FIG. 4 is a developed plan view of a straight guide ring. FIG. 5 is a developed plan view of a second group lens moving frame. It is a development top view of a 2nd outer cylinder. FIG. 4 is a developed plan view of a first outer cylinder. FIG. 3 is a diagram conceptually illustrating an operation relationship of main components of the zoom lens barrel according to the embodiment. FIG. 4 is a developed plan view showing a relationship between a first outer cylinder and a cam ring in a lens barrel stored state. FIG. 10 is a developed plan view showing a state in which the cam ring starts rotating in the extension direction from the lens barrel stored state, and the first group roller enters the inclined lead area from the rear open area of the first group guide cam groove. FIG. 4 is a developed plan view showing a relationship between a first outer cylinder and a cam ring at a wide end. FIG. 4 is a developed plan view showing a relationship between a first outer cylinder and a cam ring at a tele end. FIG. 4 is a developed plan view showing a relationship between a first outer cylinder and a cam ring in a state where the lens barrel can be disassembled. FIG. 21 is a developed plan view in which a part of FIG. 20 is enlarged. FIG. 22 is a developed plan view in which a part of FIG. 21 is enlarged. FIG. 10 is an exploded plan view showing a state where the first group roller is located in the middle of the inclined lead area of the first group guide cam groove. FIG. 23 is a developed plan view in which a part of FIG. 22 is enlarged. FIG. 24 is a developed plan view in which a part of FIG. 23 is enlarged. FIG. 25 is a developed plan view in which a part of FIG. 24 is enlarged. FIG. 9 is a developed plan view showing a relationship between a first outer cylinder and a cam ring in a lens barrel stored state, showing a different embodiment of the present invention.

Explanation of reference numerals

A Aperture ED1 ED2 ED1 'ED2' Edge LG1 First lens group LG2 Second lens group LG3 Third lens group LG4 Low pass filter S Shutter Z0 Lens barrel center axis Z1 Photographing optical axis Z2 Evacuation optical axis Z3 Optical axis of finder objective system Reference Signs List 1 1 group lens frame 1a male adjustment screw 2 1 group adjustment ring 2a female adjustment screw 2b guide projection 2c engagement claw 3 first group retaining ring 3a spring receiving section 6 2nd lens frame 8 2nd lens moving frame 8a linear guide groove 8b 2nd group cam follower 8b-1 Front cam follower 8b-2 Rear cam follower 10 2nd group straight guide ring 10a Crotch-shaped protrusion 10b Ring portion 10c Straight guide key 11 11 'Cam ring 11a Second group guide cam groove 11a-1 Front cam groove 11a- 2 Rear cam groove 11b 11b '1 group guide cam groove 11b-K Lead area open end (open end)
11b-L 11b-L 'Slant lead area 11b-X 11b-X' Front open area (open end for assembling cam follower)
11b-Y Rear open area (open end, shooting standby area, storage area)
11b-Z 11b-Z 'chevron area (zoom area, shooting control area)
11c 11e Circumferential groove 11d Barrier drive ring pressing surface 11f 11f 'Front protrusion 11g 11g' Outer diameter protrusion 11h Front end surface 11s-1 11s-1 'Front stopper surface (movement restricting portion)
11s-2 11s-2 'Rear stopper surface (movement restricting part)
11t 11t 'Lead slope 12 12' First outer cylinder (movable member, movable ring)
12a Engagement projection 12b First group adjustment ring guide groove 12c 12c 'Inner diameter flange 12d Flange opening 12e Flange rear surface 12f 12f' Rear protruding portion 12s-1 12s-1 'Front stopper surface (movement restricting portion)
12s-2 12s-2 'Rear stopper surface (movement restricting part)
12t 12t 'Lead slope 13 Second outer cylinder 13a Straight guide projection 13b Straight guide groove 13c Inner diameter flange 14 Straight guide ring 14a Straight guide projection 14b Relative rotation guide projection 14c Relative rotation guide projection 14d Circumferential groove 14e Roller guide through groove 14e-1 Circumferential groove 14e-2 Circumferential groove 14e-3 Lead groove 14f First rectilinear guide groove 14g Second rectilinear guide groove 15 Third outer cylinder 15a Rotation transmitting protrusion 15b Fitting protrusion 15c Recessed portion with spring contact 15d Relative rotation Dynamic guide projection 15e Circumferential groove 15f Roller fitting groove 17 Roller urging spring 17a Roller pressing piece 18 Helicoid ring 18a Male helicoid 18b Rotating sliding projection 18c Spur gear part 18d Rotation transmitting recess 18e Fitting recess 18f Spring inserting recess 18g Circumferential direction Groove 21 CCD holder 21a Cam protrusion 22 Fixed ring 22a Female helicoid 2b Straight guide groove 22c Slant groove 22d Rotating slide groove 22e Stopper insertion / removal hole 22z Front annular region 24 1st group biasing spring 25 Separating direction biasing spring 26 Disassembly stopper 28 Zoom gear 29 Zoom gear shaft 30 Finder gear 31 31 ′ 1st group Roller (Cam Follower)
32 Cam ring roller 32a Roller fixing screw 33 Second group rotation shaft 35 Rotation restricting pin 36 37 Second group lens frame support plate 38 Axial pressing spring 39 Second group lens frame return spring 51 AF lens frame (third group lens frame)
52 53 AF guide shaft 54 AF nut 55 AF frame biasing spring 60 CCD (solid-state image sensor)
61 packing 62 CCD base plate 64 retaining ring fixing screw 66 support plate fixing screw 70 digital camera 71 zoom lens barrel 72 camera body 73 filter holder 74 reduction gear box 75 lens drive control FPC board 76 shutter unit 77 exposure control FPC board 80 finder Unit 81a Objective window 81b 81c Movable zoom lens 81d Prism 81e Eyepiece 81f Eyepiece window 83 84 Holding frame 85 86 Guide shaft 90 Cam gear 101 Barrier cover 102 Barrier pressing plate 103 Barrier drive ring 104 105 Barrier blade 106 Barrier spring 107 Barrier Drive ring biasing spring 140 Control circuit 150 Zoom motor 160 AF motor

Claims (12)

A movable member that supports the optical element and is guided straight in the optical axis direction, and a cam ring that has a cam groove on its peripheral surface that engages a cam follower provided on the movable member.
Either the front or rear end of the cam groove is opened to the end face of the cam ring, and the cam follower is advanced or retracted into the open end of the cam groove according to the forward or reverse rotation of the cam ring,
An advancing / retreating cam mechanism for a lens barrel, comprising: a movement restricting portion for restricting detachment or detachment amount of a cam follower from the cam groove open end to the outside of the cam groove. 2. The cam mechanism according to claim 1, wherein the cam follower is positioned within an open end of the cam groove in a standby state in which photographing is not performed, and the movement restricting portion is configured to move the cam follower from the open end of the cam groove. A retractable cam mechanism for the lens barrel that restricts detachment. 3. The lens barrel advancing / retracting cam mechanism according to claim 2, wherein an open end of the cam groove is formed wider than other areas of the cam groove. 2. The cam mechanism according to claim 1, wherein the cam follower is separated from the open end of the cam groove in a standby state in which photographing is not performed, and the movement restricting section is configured to move the cam follower from the open end of the cam groove. A retractable cam mechanism for the lens barrel that limits the amount of separation. 5. The lens barrel advancing / retracting cam mechanism according to claim 2, wherein the lens barrel is a zoom lens barrel that can be stored in a camera body, and the standby state is when the zoom lens barrel is stored. The retractable cam mechanism of the lens barrel in the state. 6. The cam mechanism according to claim 1, wherein said movement restricting portion is a movable member and a lens barrel provided on a cam ring. 7. The cam mechanism according to claim 6, wherein the movable member is a movable ring that is substantially concentric with the cam ring, and the movement restricting portion includes a convex portion protruding from a cam groove forming peripheral surface of the cam ring. A lens barrel advancing and retracting cam mechanism comprising: a front and rear end surface of a movable ring which can contact the convex portion. 7. The cam mechanism according to claim 6, wherein the movable member is a movable ring substantially concentric with the cam ring, and the movement restricting portion projects from a peripheral surface of the movable ring facing the cam ring. An advancing / retreating cam mechanism for a lens barrel comprising a convex portion and one of front and rear end surfaces of a cam ring which can contact the convex portion. 9. The cam follower mechanism according to claim 1, wherein the cam groove has a cam follower that is open at the other end of the open end and at an end face opposite to the cam ring. A lens barrel advance / retreat cam mechanism having an open end. A movable member that supports the optical element and is guided straight in the optical axis direction, and a cam ring that has a cam groove on its peripheral surface that engages a cam follower provided on the movable member.
Either the front or rear end of the cam groove is opened to the end face of the cam ring, and when in a standby state in which photographing is not performed, either the inside of the open end of the cam groove or the outside of the cam groove detached from the open end. Position the cam follower on
A lens barrel advance / retreat cam mechanism comprising: a movement restricting portion that determines a moving end of a movable member in an opening direction of the cam groove opening end with respect to a cam ring in the standby state. A movable member supporting the optical element and guided straight in the optical axis direction, and a cam ring having a cam groove on a peripheral surface with which a cam follower provided on the movable member is engaged, and the cam groove can photograph the movable member. In a lens barrel advance / retreat cam mechanism having a shooting control area positioned at a position and a shooting standby area positioned at a shooting standby position different from the shooting enabled position,
Either the front or rear end of the cam groove is opened to the end face of the cam ring, and the open cam groove area is set as the photographing standby area,
A lens barrel provided with a movement restricting portion for restricting relative movement of the movable member with respect to the cam ring in a direction in which the cam follower is disengaged from the opening portion of the photographing standby region when the cam follower is located in the photographing standby region. Reciprocating cam mechanism. A movable member that supports the optical element and is guided in a straight line in the optical axis direction, and a cam ring having a cam groove on a peripheral surface with which a cam follower provided on the movable member is engaged. In a lens barrel advancing and retracting cam mechanism for moving a movable member between a photographable position and a photographing standby position,
Either the front or rear end of the cam groove is opened to the end face of the cam ring, and the cam follower is separated from the open end of the cam groove at the photographing standby position of the movable member,
When the cam follower is detached from the open end of the cam groove, a movement restricting portion for restricting relative movement of the movable member with respect to the cam ring in a direction in which the cam follower is separated from the open end of the cam groove is provided. A retractable cam mechanism for the lens barrel.

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