JP2011158592A - Extending cam mechanism for lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extending cam mechanism for a lens barrel, which has a simple configuration and excellent strength and which can shorten the axial length of a cam ring. <P>SOLUTION: The cam groove formed on the surface of the periphery of the cam ring has, at the different positions in the direction of depth: a wide groove portion, which is an open-shaped groove formed so as to open to an end face in the area close to the axial end face of the cam ring; and a narrow groove portion, which maintains an close-shaped groove formed so as not to open to the end face in the area close to the axial end face of the cam ring. A cam follower provided on a movable member positionally controlled by the cam groove has: a large-diameter portion, which is fitted into the wide groove portion of the cam groove; and a small-diameter portion, which is fitted into the narrow groove portion. At the movable end of the movable member in the direction of an optical axis relative to the cam ring, a part of the large-diameter portion is detached from the cam groove through the opening of the wide groove portion, and the small-diameter portion maintains a state of being fitted into the narrow groove portion. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a feeding cam mechanism for a lens barrel.

  Due to the demand for downsizing of the camera, it is required to shorten the axial length of the cam ring while securing the drive amount of the driven member (for example, a lens group constituting the zoom lens) by the cam ring in the optical axis direction. ing. For example, in Patent Document 1, a part of the cam groove use area at the end of the cam ring is defined as a one-sided cam groove section in which one of a pair of opposing wall surfaces (inclined surfaces) separated in the groove width direction is left and the other is removed. By forming, the axial length is shortened.

JP 2007-139964 A

  In the pay-out cam mechanism of Patent Document 1, a weak portion is formed at a portion that transitions from a double-sided cam groove section where there is a pair of opposing wall surfaces of the cam groove to a single-sided cam groove section where one of them does not exist. There was a possibility. Specifically, when the locus of the cam groove in the portion that transitions from the double-sided cam groove section to the single-sided cam groove section has a large inclination with respect to the axis of the cam ring (an angle close to the circumferential direction of the cam ring). An acute-angled thin-walled portion is easily formed between the opposing wall surface on the side where it does not exist and the cam ring end surface. Such a thin portion may be damaged when a strong force is applied from the outside.

  Further, when a part of the cam groove is a single-sided cam groove section, in order to prevent the cam follower from dropping out to the side where the opposing wall surface does not exist in the single-sided cam groove section, a separate drop-off prevention means is required, and the configuration is complicated. There is a fear.

  The present invention has been made in view of the above problems, and provides a feeding cam mechanism for a lens barrel that is excellent in strength with a simple configuration and that can shorten the axial length of a cam ring. For the purpose.

  The present invention includes a cam ring having a cam groove formed on a peripheral surface thereof and rotatable, a moving member having a cam follower engaged with the cam groove and movable in the optical axis direction, and the moving member according to the rotation of the cam ring. The lens barrel feeding cam mechanism for moving the lens back and forth in the optical axis direction has the following configuration. The cam groove has different positions in the depth direction, and is a wide groove portion that becomes an open-shaped groove that opens to the end face in the approach area to the axial end face of the cam ring, and a closing that does not open to the end face in the approach area. A narrow groove portion for maintaining the shape groove. The cam follower has a large-diameter portion that fits into the wide groove portion of the cam groove and a small-diameter portion that fits into the narrow groove portion, and at the moving end in the optical axis direction of the moving member with respect to the cam ring, a part of the large diameter portion is a portion of the wide groove portion. The small diameter part maintains the fitting with the narrow groove part through the opening and out of the cam groove. In addition, the axial direction end surface of the cam ring in the present invention is a case where the end shape of the cam ring is a non-planar shape including irregularities in the axial direction and a case where the cam ring is a flush shape not including irregularities. Regardless of the point, it indicates the entire area facing the axial direction, and does not indicate only the most projecting portion in the axial direction in the end shape including irregularities.

  More specifically, in the approach region of the cam groove to the cam ring end surface, the wide groove portion constitutes a one-sided cam groove in which one of the cam ring end surface side does not exist among the pair of opposing wall surfaces separated in the groove width direction, The narrow groove portion may be configured to constitute a double-sided cam groove in which a pair of opposing wall surfaces that are separated in the groove width direction remain. A portion of the cam groove having a combination of such a single-sided cam groove and a double-sided cam groove is a circumferential groove extending in a direction substantially perpendicular to the axis of the cam ring or a mountain-shaped locus protruding toward the end face of the cam ring. A groove or the like can be selected.

  Of the pair of opposing wall surfaces of the wide groove portion of the cam groove, one opposing wall surface that does not exist in the single-sided cam groove section extends to the end face of the cam ring along a different path from the other opposing wall surface remaining in the single-sided cam groove section. It is preferable to be provided. More specifically, the cam groove has a lead groove section that is inclined with respect to the axis of the cam ring following the approaching area to the cam ring end face, and one opposing wall surface that does not exist in the one-side cam groove section Is preferably extended to the end face of the cam ring substantially parallel to the lead groove section.

  It is preferable that the pair of opposing walls in each of the wide groove portion and the narrow groove portion of the cam groove are a pair of inclined surfaces that gradually narrow each other in the depth direction. In this case, the cam groove may be a two-stage cam groove in which an intermediate bottom surface constituting the bottom surface of the wide groove portion is formed between the pair of inclined surfaces of the wide groove portion and the pair of inclined surfaces of the narrow groove portion, Alternatively, at least one of the pair of inclined surfaces of the wide groove portion and the narrow groove portion may be a flat inclined surface having no step between the wide groove portion and the narrow groove portion.

  The lens barrel to which the present invention is applied is operable in a storage state in which a moving member having a cam follower is positioned at a rearward moving end in the optical axis direction and a photographing state in which the moving member is extended forward in the optical axis direction. It is preferable that the approach area to the cam ring end face in the groove is a storage section that determines the position of the cam follower in the storage state.

  In the lens barrel feeding cam mechanism of the present invention described above, when the cam follower is located in the cam groove in the region close to the cam ring end face, a part of the large diameter portion of the cam follower is the wide groove portion of the cam groove ( The cam follower is disengaged from the cam groove through the opening of the one-side cam groove), and the engagement of the small diameter portion of the cam follower with the narrow groove portion (double-side cam groove) of the cam groove is maintained. Therefore, with respect to the wide groove portion, the degree of freedom in design at the cam ring end portion is increased, and it is possible to avoid the formation of a thin end surface wall portion between the wide groove portion and the cam ring end surface. In addition, since the cam follower and the cam groove can prevent the cam follower from dropping off, no separate dropping prevention means is required and the configuration is simple. In addition, even if an end wall having a sufficient strength is formed between the narrow groove and the cam ring end face, the cam ring shaft is compared with a case where the back of the wide groove is covered with an end wall having the same thickness. A reduction in direction length is achieved.

It is sectional drawing in the imaging state (zoom area) which shows one Embodiment of the zoom lens-barrel to which this invention is applied. It is sectional drawing in the accommodation (collapse) state of the zoom lens barrel. It is a disassembled perspective view of the main components of the zoom lens barrel. It is an expansion | deployment top view of a cam ring. It is a development top view of a delivery cylinder, a rectilinear guide ring, and a 2 group lens moving frame. FIG. 6 is a perspective view showing a part of a feeding cylinder and a cam ring when the first group cam follower is located in a connecting curved section of the first group control cam groove. It is sectional drawing of the 1st group control cam groove which follows the D1-D1 line | wire of FIG. FIG. 6 is a plan view showing a state in which the first group cam follower is located in the storing section of the first group control cam groove in the first embodiment of the present invention. It is sectional drawing which follows the D2-D2 line | wire of FIG. FIG. 10 is a perspective view showing the vicinity of a storing section of the first group control cam groove in FIGS. 8 and 9. FIG. 10 is a perspective view showing the vicinity of a storing section of the first group control cam groove in FIGS. 8 and 9. In the 2nd Embodiment of this invention, the 1st group cam follower is a top view which shows the state located in the storage area of a 1st group control cam groove. It is sectional drawing which follows the D3-D3 line | wire of FIG. FIG. 14 is a perspective view showing the vicinity of the storage section of the first group control cam groove in FIGS. 12 and 13. FIG. 14 is a perspective view showing the vicinity of the storage section of the first group control cam groove in FIGS. 12 and 13. In the 3rd Embodiment of this invention, the 1st group cam follower is a top view which shows the state located in the storage area of a 1st group control cam groove. It is sectional drawing which follows the D4-D4 line | wire of FIG. FIG. 18 is a perspective view showing the vicinity of a storing section of the first group control cam groove in FIGS. 16 and 17. FIG. 18 is a perspective view showing the vicinity of a storing section of the first group control cam groove in FIGS. 16 and 17. In the 4th Embodiment of this invention, the 1st group cam follower is a top view which shows the state located in the rearmost area | region of the optical axis direction of a 1st group control cam groove. It is a top view of the cam groove and cam follower in the cam ring end part vicinity as a comparative example of this invention. It is sectional drawing which follows the D5-D5 line | wire of FIG. It is a perspective view which shows the circumferential direction groove area vicinity of the cam groove of a comparative example. It is a perspective view which shows the circumferential direction groove area vicinity of the cam groove of a comparative example.

  1 and 2 show an embodiment of a retractable zoom lens barrel ZL to which the present invention is applied. The photographing optical system of the zoom lens barrel ZL includes a first lens group LG1, a shutter S, an aperture variable aperture A, a second lens group LG2, a third lens group LG3, a low-pass filter 25, and an image pickup in order from the object (subject) side. An element 26 is provided. 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 zoom lens barrel ZL has a cylindrical housing 22 as a fixing member, and the image sensor holder 21 is fixed to the rear portion of the housing 22. The low-pass filter 25 and the image sensor 26 are unitized and fixed to the front surface of the image sensor holder 21.

  The third lens group LG3 is a focus lens group in the zoom lens barrel ZL. As shown in FIG. 3, the third group lens frame 51 includes a lens holding cylinder 51a that holds the third lens group LG3, and a pair of guide arm parts 51b that extend from the lens holding cylinder 51a in the outer diameter direction. , 51c. A boundary portion between the lens holding cylinder portion 51a and the guide arm portion 51c is formed with a second group lens housing recess 51d into which the second lens group LG2 held by the second group lens holding frame 6 can enter. A guide shaft 52 fixed to the housing 22 and the image sensor holder 21 is inserted into a guide hole formed in one guide arm portion 51b, and the third group lens frame 51 is inserted in the optical axis direction via the guide shaft 52. It is supported so that it can move straight. An anti-rotation portion provided at the tip of the other guide arm portion 51 c engages with a rotation restricting portion (not shown) formed in the housing 22 to restrict the rotation of the third group lens frame 51. The third group lens frame 51 is urged forward in the optical axis direction by a third group urging spring 55 formed of a torsion spring supported on the outer surface of the housing 22, and is brought into contact with the AF nut 54 to restrict forward movement. . The AF nut 54 is screwed into the lead screw 58 and is moved in the optical axis direction by rotating the lead screw 58 by the AF motor 160. Therefore, the third group lens frame 51 is moved in the optical axis direction by driving the AF motor 160.

  A zooming group (cam ring) block that is driven and controlled by the zoom motor 150 is supported inside the housing 22, in addition to the support driving means for the third group lens frame 51. As shown in FIG. 3, the variable power group (cam ring) block includes a straight guide ring 10, a cam ring 11, a feeding cylinder 12, and a second group lens block 80.

  The cam ring 11 constitutes an external appearance cylinder of the zoom lens barrel ZL together with the feeding cylinder 12 and has a guide projection 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 gear 28 rotated by the zoom motor 150 (FIG. 3) by the gear portion 11b, and moves in the optical axis direction while rotating by the guide of the cam ring guide groove 22a.

  The rectilinear guide ring 10 is guided so as to be linearly movable in the optical axis direction by engaging the rectilinear guide protrusion 10a slidably with a rectilinear guide groove 22b formed on the inner surface of the housing 22. By sandwiching the rotation guide claw 11c between the wall portion constituting the base portion of the rectilinear guide projection 10a and the rotation guide claw 10b, the rectilinear guide ring 10 and the cam ring 11 are capable of relative rotation and move together in the optical axis direction. Are so coupled.

  The second group lens block 80 has a configuration in which the shutter block 100 is fixed to the front portion of the second group lens moving frame 8, and a rectilinear guide key 8 a protruding in the outer diameter direction from the second group lens moving frame 8 is connected to the rectilinear guide ring 10. By being slidably engaged with the rectilinear guide slot 10c, which is a long hole in the optical axis direction formed in the above, the linear guide is guided in the optical axis direction. The shutter S is composed of a plurality of shutter blades supported by an axis parallel to the optical axis O, and the shutter S is opened and closed by driving the plurality of shutter blades by an actuator built in the shutter block 100. At the rear of the shutter block 100, an aperture variable stop A whose aperture diameter changes according to the state of the zoom lens barrel ZL is provided. The aperture variable aperture stop A is composed of a plurality of aperture blades supported by an axis parallel to the optical axis O, and is wider than the tele end side (lower half cross section in FIG. 1) of the zoom range (in FIG. 1). The opening degree is switched so as to reduce the aperture diameter in the upper half section), and in both states, the aperture diameter allows a part of the second lens group LG2 to enter the aperture stop.

  Further, inside the second group lens moving frame 8, a second group lens holding frame 6 holding the second lens group LG2 is supported. The second group lens holding frame 6 is supported so as to be swingable about a rotation axis whose axis is directed in the optical axis direction. In the photographing state shown in FIG. 1, the center of the second lens group LG2 is set to the optical axis O. Is held at the insertion position to match. When the second lens group moving frame 8 is moved rearward in the optical axis direction by the storing operation of the zoom lens barrel ZL, the second lens group holding frame 6 comes into contact with the detachment control protrusion 40 provided on the image sensor holder 21 and is pressed. In the retracted state shown in FIG. 2, the second lens group LG2 is moved away from the radial through hole 8s formed in the second group lens moving frame 8 or the radial through hole 10s formed in the linear guide ring 10. Retained. The detailed support driving structure of the second group lens holding frame 6 is not related to the gist of the present invention, and thus detailed description thereof is omitted.

  The second group cam follower CF2 provided in the second group lens moving frame 8 is slidably engaged with the second group control cam groove CG2 formed on the inner peripheral surface of the cam ring 11. As shown in FIGS. 4 and 5, the second group control cam groove CG2 and the second group cam follower CF2 are provided in three different positions in the circumferential direction of the cam ring 11 and the second group lens moving frame 8, respectively. Yes. The second group cam follower CF2 is provided on the outer diameter portion of the rectilinear guide key 8a, and protrudes to an engagement position with the second group cam follower CF2 through a rectilinear guide slot 10c that penetrates the rectilinear guide ring 10 in the radial direction. Since the second group lens moving frame 8 (second group lens block 80) is guided linearly in the direction of the optical axis through the straight guide ring 10, when the cam ring 11 rotates, the second group lens moving frame 8 (2 group lens block 80) has 2 according to the shape of the second group control cam groove CG2. The group lens moving frame 8 (second group lens block 80) moves in a predetermined locus in the optical axis direction. 4, R2, W2, and T2 in the second group control cam groove CG2 are in the retracted state of the zoom lens barrel ZL (FIG. 2), the wide end (upper half of FIG. 1), and the tele end of the zoom range, respectively. The position of the second group cam follower CF2 when in the lower half of FIG. 1 is shown.

  A first lens group LG1 is held in the feeding cylinder 12. The feeding cylinder 12 is guided in a straight line in the optical axis direction by slidably engaging a straight guide key 12a (FIGS. 1 and 5) provided on the inner surface side with a straight guide groove 10d of the straight guide ring 10. Yes. In FIG. 1, the linear guide groove 10d and the linear guide key 12a, which are the linear guide mechanism of the feeding cylinder 12, and the linear guide slot 10c and the linear guide key 8a, which are the linear guide mechanisms of the second group lens block 80, are located at the same sectional position in FIG. As can be seen from FIG. 3, the actual circumferential position of each linear guide mechanism is different.

  A first group cam follower CF1 projecting in the outer diameter direction from the vicinity of the rear end of the feeding cylinder 12 is slidably engaged with the first group control cam groove CG1 formed on the inner peripheral surface of the cam ring 11. As shown in FIGS. 4 and 5, the first group control cam groove CG <b> 1 and the first group cam follower CF <b> 1 are provided in three different positions in the circumferential direction of the cam ring 11 and the feeding cylinder 12. Since the feeding cylinder 12 is linearly guided in the optical axis direction via the linear guide ring 10, when the cam ring 11 rotates, the feeding cylinder 12 follows a predetermined locus in the optical axis direction according to the shape of the first group control cam groove CG1. Moving. 4, R1, W1, and T1 in the first group control cam groove CG1 are respectively in the retracted state of the zoom lens barrel ZL (FIG. 2), the wide end (upper half of FIG. 1), and the tele end of the zoom range. The position of the first group cam follower CF1 when in the lower half of FIG. 1 is shown.

  As shown in FIG. 7, the first group control cam groove CG <b> 1 has a wide main body guide portion (a cross-sectional shape in a direction orthogonal to the trajectory occupies from the inner peripheral surface side of the cam ring 11 to a midway position in the depth direction ( Wide bottom groove portion) CG1-a and a bottomed cam groove having a two-step bottom shape having a narrow head guide portion (narrow groove portion) CG1-b occupying from the main body guide portion CG1-a to the cam groove bottom portion. ing. The main body guide portion CG1-a has a pair of inclined surfaces (opposite wall surfaces) Kaf and Kar (FIG. 7) that are spaced apart in the groove width direction and gradually narrowed as the depth advances (upward in FIG. 7). It has a trapezoidal cross section. Similarly, the head guide portion CG1-b is also separated by a pair of inclined surfaces (opposite wall surfaces) Kbf, Kbr (see FIG. 7) that are spaced apart in the groove width direction and gradually narrower each other as they proceed in the depth direction (upward in FIG. 7). 7) has a trapezoidal cross section. Between the main body guide portion CG1-a and the head guide portion CG1-b, a pair of intermediate bottom surfaces Kc constituting the bottom portion of the main body guide portion CG1-a are formed. The outer edge in the groove width direction of the pair of intermediate bottom surfaces Kc constitutes the narrowest portion of the groove width in the main body guide portion CG1-a, and the inner edge in the groove width direction of the pair of intermediate bottom surfaces Kc is the head The guide part CG1-b forms the widest groove. That is, the main body guide part CG1-a has a wider groove width than the head guide part CG1-b, and the head guide part CG1-b constitutes a narrow groove part in the first group control cam groove CG1, and the main body guide part CG1-a constitutes a wide groove portion in the first group control cam groove CG1.

  As shown in FIG. 4, the first group control cam groove CG1 includes a lead section CG1-c extending obliquely forward in the optical axis direction from the vicinity of the storage position R1, and a zoom cam section CG1- from the wide end position W1 to the tele end position T1. d is included. The zoom cam section CG1-d has a mountain-shaped locus that protrudes rearward in the optical axis direction, and the lead section CG1-c and the zoom cam section CG1-d are convex forward in the optical axis direction. They are connected by a connecting curved section CG1-e of a mountain-shaped locus. Further, the tip of the tele end position T1 is a terminal section CG1-f of the first group control cam groove CG1. The connecting curved section CG1-e and the terminal section CG1-f are located at the foremost position in the optical axis direction of the first group control cam groove CG1 (approaching the front end face that is one of the front and rear axial end faces of the cam ring 11). It is an area. As shown in FIG. 4, in the forefront region of the first group control cam groove CG1, an inclined surface Kaf positioned forward in the optical axis direction of the pair of inclined surfaces Kaf and Kar constituting the main body guide portion CG1-a is It is a narrow partial inclined surface Kav from the midway position in the depth direction to the cam groove bottom (not reaching the inner peripheral surface of the cam ring 11), and the inner peripheral surface of the cam ring 11 (from the partial inclined surface Kav) Up to the peripheral surface side opening of the first group control cam groove CG1 is formed as an axis orthogonal surface CG1-g substantially orthogonal to the optical axis O (the axis of the cam ring 11). The front portion of the axis orthogonal surface CG1-g is closed by a front end wall portion that constitutes the front end of the cam ring 11.

  The first group cam follower CF1 is fitted into a large diameter main body portion (large diameter portion) CF1-a that can be fitted into the main body guide portion CG1-a of the first group control cam groove CG1 and the head guide portion CG1-b. This is a two-stage protrusion having a possible small-diameter head (small-diameter portion) CF1-b. The main body portion CF1-a is a conical portion that can come into contact with the pair of inclined surfaces Kaf, Kar of the main body guide portion CG1-a, and the head portion CF1-b is a pair of head portion guide portions CG1-b. It is a cone-shaped part which can contact | abut with respect to these inclined surfaces Kbf and Kbr. An intermediate annular surface CF1-c that faces the intermediate bottom surface Kc of the first group control cam groove CG1 is formed between the main body portion CF1-a and the head portion CF1-b. As shown in FIGS. 5, 6, 8, and 9, the first group cam follower CF <b> 1 further includes a portion of the main body portion CF <b> 1-a in a circumferential direction region in which the first group control cam groove CG <b> 1 is removed. An axis orthogonal plane CF1-d substantially parallel to the axis orthogonal plane CG1-g is formed. When the first group cam follower CF1 is seen in a plan view as shown in FIGS. 5 and 8, it has a “D” shape surrounded by the main body portion CF1-a and the axis orthogonal plane CG1-g. When the first group cam follower CF1 is located in the connecting curved section CG1-e or the end section CG1-f of the first group control cam groove CG1, the main body CF1-a abuts on the partial inclined surface Kav and the axis orthogonal surface CF1 -d faces the axis orthogonal plane CG1-g with a slight distance.

  The detailed shape of the storage section (circumferential groove) CG1-x including the storage position R1 of the first group control cam groove CG1 is shown in FIGS. This storage section CG1-x is an area located closest to the rear in the optical axis direction (close to the rear end face of one of the front and rear axial ends of the cam ring 11) in the first group control cam groove CG1, A circumferential groove that is substantially orthogonal to the axis O (the axis of the cam ring 11) and faces the circumferential direction of the cam ring 11 is formed. The head guide portion CG1-b is formed as a double-sided cam groove (closed shape groove) in which a pair of front and rear inclined surfaces Kbf, Kbr remain in the storage section CG1-x following the lead section CG1-c. That is, the head guide portion CG1-b in the storage section CG1-x has a pair of inclined surfaces Kbf and Kbr spaced apart at a constant interval in the front and rear directions in the optical axis direction, and is inclined behind the optical axis direction. The rear portion of the surface Kbr is closed by the rear end wall portion 11d of the cam ring 11. The thickness of the rear end wall portion 11d in the optical axis direction is indicated by “T” in FIGS. As can be seen from FIG. 9, the thickness of the rear end wall portion 11d increases as the depth of the first group control cam groove CG1 increases. T indicates the maximum thickness portion of the rear end wall portion 11d. . Further, in the first group control cam groove CG1, the head CF1-b of the first group cam follower CF1 is placed on the rear end side of the cam ring 11 with respect to the head guide portion CG1-b following the storage section CG1-x. An insertion / removal section CG1-s that allows insertion / removal is formed. The effective use area of the first group control cam groove CG1 used in the use state (product completion state) of the zoom lens barrel ZL is a storage section excluding the insertion / removal section CG1-s and the end section CG1-f described above. CG1-x, lead section CG1-c, and zoom cam section CG1-d. In a normal use state, the rotation range of the cam ring 11 (the driving amount of the zoom motor 150) is controlled so that the first group cam follower CF1 does not reach the insertion / removal section CG1-s or the terminal section CG1-f. The

  Unlike the head guide portion CG1-b, the main body guide portion CG1-a in the storage section CG1-x has an inclined surface Kaf in the optical axis direction front, but an inclined surface Kar in the optical axis direction rear side. It does not exist and is formed as a single-sided cam groove (open shape groove) opened on the rear end face side of the cam ring 11. Specifically, the inclined surface Kar on the rear side in the optical axis direction of the main body guide portion CG1-a extends linearly to the rear end of the cam ring 11 in parallel with the locus of the lead section CG1-c. It communicates with the rear end face. In other words, the main body guide portion CG1-a has a constant width until the lead section CG1-c, and is regarded as a shape in which the groove width in the circumferential direction of the cam ring 11 is enlarged only in the storage section CG1-x. be able to.

  As shown in FIGS. 8, 9, and 11, when the first group cam follower CF1 is positioned within the storing section CG1-x of the first group control cam groove CG1, the main body portion CF1-a excluding the axis orthogonal plane CF1-d. Of the first group and the front inclined surface Kaf of the main body guide portion CG1-a can restrict the forward movement of the first group cam follower CF1 in the optical axis direction, but the main body portion CF1-a. A part of the rear of the first group is separated to the rear of the first group control cam groove CG1, and the first group cam follower CF1 is not restricted to move rearward in the optical axis direction by the main body guide part CG1-a. On the other hand, the head portion CF1-b of the first group cam follower CF1 is engaged with the head guide portion CG1-b that maintains the double-sided cam groove even in the storage section CG1-x, and a pair of inclined surfaces Kbf , Kbr restricts the back-and-forth movement in the optical axis direction, so that the separation of the first group cam follower CF1 from the first group control cam groove CG1 is restricted.

  When the first group cam follower CF1 is located in a region other than the storage section CG1-x in the first group cam follower CF1, the main body portion CF1-a is located between the pair of inclined surfaces Kaf, Kar of the main body guide portion CG1-a. The position of the first group cam follower CF1 is controlled by the main body guide portion CG1-a. Of the first group control cam groove CG1, the main body guide portion CG1-a is larger in both groove width and depth than the head guide portion CG1-b, so that the storage section is used from the viewpoint of high-accuracy position control. Except for CG1-x, it is preferable to guide the first group cam follower CF1 using the inclined surfaces Kaf, Kar of the main body guide portion CG1-a. In this case, in order to prevent interference with the main body guide portion CG1-a due to an accuracy error, a loose fitting relationship with a slight margin should be provided between the head guide portion CG1-b and the head portion CF1-b. Good. As described above, in the storage section CG1-x, the position of the first group cam follower CF1 in the optical axis direction is restricted by the fitting of the head guide portion CG1-b and the head section CF1-b, but the storage section CG1- x is an area used when the zoom lens barrel ZL is housed. At this time, since it is not required in terms of optical performance to strictly position the first lens group LG1 supported by the feeding cylinder 12, the head guide portion CG1. Even if it is a relationship in which -b and head CF1-b are loosely fitted, there is no practical problem.

  The zoom lens barrel ZL having the above structure operates as follows. When the zoom motor 150 is driven forward and backward in the photographing state (zoom range) shown in FIG. 1, the cam ring 11 moves in the optical axis direction with respect to the housing 22. The position of the cam ring 11 in the optical axis direction is controlled by the locus of the cam ring guide groove 22a. The follower cylinder 12 that supports the first lens group LG1 and the second group lens block 80 (second group lens moving frame 8) that supports the second lens group LG2 have cam followers CF1 and CF2 respectively corresponding to the rotation of the cam ring 11. The guides of the cam grooves CG1 and CG2 are guided to move in the direction of the optical axis. At the wide end in the upper half of FIG. 1, the distance between the first lens group LG1 and the second lens group LG2 is large, and at the tele end in the lower half of FIG. The interval between the first lens group LG1 and the second lens group LG2 is reduced. In the entire zoom range from the wide end to the tele end, the position of the first group cam follower CF1 is controlled by the zoom cam section CG1-d of the first group control cam groove CG1. In the zoom cam section CG1-d, the first-group control cam groove CG1 has a pair of inclined surfaces Kaf, Kar and a pair of inclined surfaces Kbf, Kbr, both of the main body guide portion CG1-a and the head guide portion CG1-b. Because of the cam groove, the entire first group cam follower CF1 (particularly the large diameter portion CF1-a) is guided by the first group control cam groove CG1, and the position of the feeding cylinder 12 can be controlled with high accuracy. In the entire zoom range from the wide end to the tele end, the second group lens holding frame 6 is held at an insertion position (FIG. 1) in which the center of the second lens group LG2 coincides with the optical axis O.

  On the other hand, when the zoom motor 150 is driven in the lens barrel storage direction from the photographing state shown in FIG. 1 (more specifically, the wide end in the upper half of FIG. 1), the guide projection 11a receives the guide of the cam ring guide groove 22a and the cam The ring 11 is moved backward in the optical axis direction while rotating. The feeding cylinder 12 and the second group lens block 80 (second group lens moving frame 8) move rearward in the optical axis direction together with the cam ring 11 with predetermined relative movement along the locus of the cam grooves CG1 and CG2 on the cam ring 11. To do. In this storing operation, the first group cam follower CF1 is moved from the connecting curved section CG1-e of the first group control cam groove CG1 to the storing section CG1-x (storage position R1) through the lead section CG1-c. When the first group cam follower CF1 passes through the connecting curved section CG1-e, the main body portion CF1-a maintains the contact between the front partial inclined surface Kav and the rear inclined surface Kar in the optical axis direction. The cam follower CF1 does not fall off from the first group control cam groove CG1 and the guide is not released. When the second group lens holding frame 6 moves rearward in the optical axis direction together with the second group lens moving frame 8 and approaches the image sensor holder 21, the second group lens holding frame 6 rotates toward the detached position, and the detached position. (Fig. 2).

  In the storage operation of the zoom lens barrel ZL, when the first group cam follower CF1 is moved to the storage section CG1-x (storage position R1) via the lead section CG1-c of the first group control cam groove CG1, FIG. 8, 9 and 11, a part of the rear part of the main body part CF1-a of the first group cam follower CF1 is detached rearward from the main body guide part CG1-a of the first group control cam groove CG1. However, as described above, the head CF1-b maintains the engagement with the head guide portion CG1-b, which is a double-sided cam groove, and the first group cam follower CF1 as a whole is detached from the first group cam follower CF1. Held without.

  In the zoom lens barrel ZL feeding cam mechanism described above, the storage section CG1-x, which is the area closest to the rear end surface of the cam ring 11 in the first group control cam groove CG1, is formed in the main body guide portion CG1 having a wide groove width. Since -a is formed as a single-sided cam groove that does not have one inclined surface Kar and is open at the rear end surface of the cam ring 11, the main body guide portion CG1-a is left as a double-sided cam groove, and the rear side is closed. The length of the cam ring 11 in the optical axis direction can be shortened as compared with the form in which the wall portion is formed. On the other hand, in the storage section CG1-x, the head guide portion CG1-b is left as a double-sided cam groove so that the holding of the first group cam follower CF1 is maintained. There is no risk of falling off the ring 11, and it is not necessary to provide a separate mechanism for preventing the cam follower from falling off. Since the groove width of the head guide portion CG1-b is narrower than that of the main body guide portion CG1-a, the rear end wall portion 11d that closes the rear portion of the head guide portion CG1-b is formed with a sufficient thickness (T). The effect of shortening the axial length of the cam ring 11 is obtained.

  Further, in the region from the vicinity of the rear end of the lead section CG1-c to the storing section CG1-x, the head guide section CG1-b can guide the first group cam follower CF1, so the main body guide section CG1-a is set to 1 It is not necessary to make the shape considering the guidance of the group cam follower CF1, and the degree of freedom in design is increased. For example, the inclined surface Kar on the rear side of the main body guide part CG1-a does not trace the movement path of the first group cam follower CF1 from the lead section CG1-c toward the storing section CG1-x, but in the lead section CG1-c. It continues to the rear end of the cam ring 11 with the following linear trajectory (with a trajectory different from the forward inclined surface Kaf). Thus, the force of the first group cam follower CF1 is not applied to the rear end region of the rear inclined surface Kar indicated by “Q” in FIG. 8, and there is no problem in strength.

  Comparative examples with the present invention are shown in FIGS. The cam groove CGn of this comparative example has a basic trajectory (movement trajectory of the cam follower CFn) from the lead section CGn-c to the circumferential groove section CGn-x, which is the first group control cam according to the embodiment of the present invention described above. It is common with that of the groove CG1. The cam groove CGn is formed as a single-sided cam groove in which the rear inclined surface Knr does not exist among the pair of opposed inclined surfaces Knf and Knr in the circumferential groove section CGn-x facing the rear end of the cam ring 11n. The cam follower CFn is a conical protrusion held between the inclined surfaces Knf and Knr of the cam groove CGn. In the circumferential groove section CGn-x, a part of the rear of the cam follower CFn is behind the cam groove CGn. It protrudes.

  In this comparative example, the cam follower CFn and the cam groove CGn are not provided with a structure for preventing the cam follower CFn from dropping backward from the circumferential groove section CGn-x. . Examples of well-known drop-off prevention means include a mechanical contact portion provided between the feeding cylinder 12n having the cam follower CFn and another member, and the feeding cylinder 12n forwardly biasing the cam follower CFn into the cam groove CGn. Examples include a biasing member that presses against the inclined surface Knf. However, in any of the embodiments, complication of the structure is inevitable as compared with the structure of the present invention in which the drop-off preventing structure is completed only between the cam groove and the cam follower. Further, if there is an accuracy error between the mechanical contact portion provided at another position, the cam groove CGn, and the cam follower CFn, the optical axis direction position shown in FIGS. There is a possibility that the cam follower CFn may be held by being displaced. In this case, the cam follower CFn cannot smoothly enter the lead section CGn-c of the cam groove CGn simply by rotating the cam ring 11n.

  Further, in the comparative example, since it is necessary to guide the cam follower CFn to the circumferential groove section CGn-x, not only the front inclined surface Knf but also the rear inclined surface Knr, the lead section CGn-c to the circumferential groove section CGn- It is necessary to make the shape smoothly following x (tracing the movement locus of the cam follower CFn), and at the end portion of the rear inclined surface Knr, the cam ring 11n is thin with an acute angle that is extremely thin in the axial direction. Part 11 nm is formed. Unlike the “Q” region of the embodiment of the present invention shown in FIG. 8, this thin portion 11 nm receives a force from the cam follower CFn, and therefore when a large force acts in the direction of arrow F (FIG. 21) via the cam follower CFn. Easy to break. In particular, the thin portion 11 nm is thinner than the thick portion that fills the space between the rear inclined surface Kar and the rear end of the cam ring 11 in the “Q” region of FIG. The risk is high. When the cam ring 11n and the feeding cylinder 12n are external members of the lens barrel like the cam ring 11 and the feeding cylinder 12 of the zoom lens barrel ZL according to the embodiment of the present invention, the cam follower CFn is increased from the cam follower CFn to the thin portion 11nm by an external force. Since it is assumed that force is applied, the presence of a fragile part such as a thin part 11 nm is not preferable. However, in order to avoid the formation of the thin portion 11 nm, if a configuration is adopted in which the rear inclined surface Knr is left in the circumferential groove section CGn-x and the rear portion is closed by the flesh portion (wall portion) of the cam ring 11n, 11n becomes longer in the optical axis direction, which is contrary to the demand for downsizing.

  On the other hand, in the embodiment of the present invention, as described above, the position control of the first group cam follower CF1 at the rear end portion of the cam ring 11 is performed by the narrow head guide portion CG1 in the first group control cam groove CG1. The wide body guide part CG1-a has a shape that opens at the rear end of the cam ring 11 without tracing the movement trajectory of the first group cam follower, so that it is weak like the thin part 11 nm of the comparative example. There is no part. In other words, according to the configuration of the present invention, it is possible to freely determine the rear end shape of the main body guide portion CG1-a so that there is no weak portion such as the thin-walled portion 11nm. Since the head guide portion CG1-b is not opened at the rear end of the cam ring 11, the rear end wall portion 11d that closes the rear portion does not become a tapered thin portion like the thin portion 11nm, and has sufficient strength. Can be secured. As described above, since the groove width of the head guide portion CG1-b is narrower than that of the main body guide portion CG1-a, even if the head guide portion CG1-b and the rear end wall portion 11d are combined, 11 can occupy a smaller space than the case where the entire main body guide portion CG1-a is left, and the cam ring 11 can be made compact.

  FIG. 12 et seq. Show different embodiments of the present invention. In each of the following embodiments, portions common to the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted. The advantages of the first embodiment shown in comparison with the comparative example can be obtained in the following embodiments as well.

  12 to 15 show a second embodiment. In the first embodiment, the first group control cam groove CG1 has an intermediate bottom surface portion Kc between the inclined surfaces Kaf and Kar of the main body guide portion CG1-a and the inclined surfaces Kbf and Kbr of the head guide portion CG1-b. According to this, the first group cam follower CF1 was a two-step projection having an intermediate annular surface CF1-c between the main body CF1-a and the head CF1-b. The second embodiment is different in that the inner surface of the first group control cam groove CG101 and the outer surface of the first group cam follower CF101 are flush with no step in the middle.

  Specifically, when the first group cam follower CF101 is positioned within the storage section (circumferential groove) CG101-x of the first group control cam groove CG101, as shown in FIG. 12 is not subject to movement restriction in the rearward direction of the optical axis by the first group control cam groove CG101 (projects toward the rear end side of the cam ring 11), and only a part on the front end side in the outer diameter direction The first group control cam groove CG101 is in a state of being subjected to movement restriction in the rear direction of the optical axis. According to the first embodiment, in the first group control cam groove CG101, the double-sided cam groove portion on the bottom side that restricts rearward movement of the first group cam follower CF101 in the storage section CG101-x (more than the phantom line P1 in FIG. 13). An upper region) is a head guide portion (narrow groove portion) CG101-b, and a single-sided cam groove portion (region below the imaginary line P1 in FIG. 13) on the cam ring inner peripheral surface side where rearward movement restriction is not performed. Let it be a main body guide part (wide groove part) CG101-a. Further, in the first group cam follower CF101, the tip portion (region above the imaginary line P1 in FIG. 13) that fits in the head guide portion CG101-b in the storage section CG101-x is the head portion (small diameter portion) CF101-b. A base portion (region below the imaginary line P1 in FIG. 13) located in the main body guide portion CG101-a in the storage section CG101-x is defined as a main body portion (large diameter portion) CF101-a. FIGS. 12, 14 and 15 show a virtual line P2 indicating a conceptual boundary between the main body guide part CG101-a and the head guide part CG101-b of the first group control cam groove CG101. The front inclined surfaces (opposite wall surfaces) Kaf101, Kbf101 and the rear inclined surfaces (opposite wall surfaces) Kar101, Kbr101 in the main body guide portion CG101-a and the head guide portion CG101-b are flush with each other (continuous) It has an inclined surface. As can be seen from FIGS. 12, 13, and 15, the first group cam follower CF101 is formed as a flush conical portion having no step between the main body portion CF101-a and the head portion CF101-b. .

  In the state where the first group cam follower CF101 is located in the storing section CG101-x of the first group control cam groove CG101 as shown in FIGS. 12, 13, and 15, the front surfaces of the main body portion CF101-a and the head portion CF101-b The region comes into contact with the inclined surfaces Kaf101 and Kbf101 in front of the main body guide part CG101-a and the head guide part CG101-b, and the movement of the first group cam follower CF101 in the optical axis direction is restricted. At this time, a part of the rear portion of the main body portion CF101-a protrudes rearward of the first group control cam groove CG101, but the head portion CF101-b is formed on the inclined surface Kbr101 on the rear side in the optical axis direction of the head guide portion CG101-b. By abutting, separation of the first group cam follower CF101 rearward from the first group control cam groove CG101 is restricted. Therefore, similarly to the first embodiment, the length of the cam ring 11 in the optical axis direction can be shortened while maintaining the holding of the first group cam follower CF1 in the storage section CG101-x. In the storage section CG101-x, the inclined surface Kar101 behind the main body guide portion CG101-a does not trace the movement locus of the first group cam follower CF101, and the linear locus following the lead interval CG101-c By extending to the rear end of the cam ring 11 as it is, the force from the first group cam follower CF101 is not received in the vicinity of the rear end portion of the inclined surface Kar101, and the structure is excellent in strength.

  16 to 19 show a third embodiment. In this embodiment, the elements of the first embodiment and the second embodiment are included with respect to the cross-sectional shapes of the first group cam follower CF102 and the first group control cam groove CG102. First, when the first group cam follower CF102 is positioned within the storing section (circumferential groove) CG102-x of the first group control cam groove CG102, as shown in FIG. No movement restriction in the rearward direction of the optical axis by the group control cam groove CG102 (projecting toward the rear end side of the cam ring 11), and only a part of the front end side is restricted by the first group control cam groove CG102. In the point which will be in the state which receives, it is common with each previous embodiment. According to the first embodiment, in the first group control cam groove CG102, the double-sided cam groove portion that restricts the rearward movement of the first group cam follower CF102 in the storage section CG102-x (an area above the imaginary line P3 in FIG. 17). ) Is a head guide portion (narrow groove portion) CG102-b, and a single-sided cam groove portion (region below the imaginary line P3 in FIG. 17) where rearward movement restriction is not performed is a main body guide portion (wide groove portion) CG102-a. And Further, in the first group cam follower CF102, a tip portion (region above the imaginary line P3 in FIG. 17) fitted to the head guide portion CG102-b is a head (small diameter portion) CF102-b, and the main body guide portion CG102- A base portion (region below the imaginary line P3 in FIG. 17) that fits in a is defined as a main body portion (large diameter portion) CF102-a.

  Of the head portion CF102-b of the first group cam follower CF102, the half front portion CF102-bf constituting the front half is formed as a flush conical portion having no step with the main body portion CF102-a. Yes. On the other hand, the half rear portion CF102-br forming the rear half of the head portion CF102-b is formed as a conical portion having a smaller diameter than the half front portion CF102-bf, and is between the main body portion CF102-a. A step is formed by the intermediate annular surface CF102-c.

  The storage section CG102-x of the first group control cam groove CG102 has a front inclined surface (opposite wall surface) Kaf102 of the main body guide portion CG102-a and a front inclined surface of the head guide portion CG102-b (at the front portion in the optical axis direction). The opposing wall surface (Kbf102) is a flat inclined surface with no step. 16, 18, and 19, the boundary between the front inclined surfaces Kaf102 and Kbf102 is conceptually indicated by a virtual line P4. On the other hand, in the rear portion of the storage section CG102-x in the optical axis direction, the rear inclined surface Kar (opposing wall surface) 102 of the main body guide portion CG102-a does not exist (opened at the rear end of the cam ring 11), and the head Only the rear inclined surface (opposing wall surface) Kbr102 of the guide portion CG102-b is left. The rear inclined surface Kbr102 has a shape with which a small-diameter half rear portion CF102-br of the head CF102-b of the first group cam follower CF102 can abut. The rear inclined surface Kbr102 is interrupted on the way from the storage section CG102-x to the lead section CG102-c, and the head guide portion CG102-b is formed by the pair of inclined surfaces before the lead section CG102-c. The groove width is widened so that the front half part CF102-bf can be guided (so as to be loosely connected to the half rear part CF102-br). The reason why the formation area of the rear inclined surface Kbr102 is only a part including the storage section CG102-x is that the first group cam follower CF102 moves from the storage section CG102-x to the lead section CG102-c. This is to avoid interference between the front half CF102-bf having a larger diameter than the rear half CF102-br and the rear inclined surface Kbr102.

  In the state where the first group cam follower CF102 is located in the storing section CG102-x of the first group control cam groove CG102 as shown in FIGS. 16, 18 and 19, half of the main body CF102-a and the head CF102-b is used. The front part CF102-bf abuts against the front inclined surfaces Kaf102, Kbf102 of the main body guide part CG102-a and the head guide part CG102-b, respectively, and the movement of the first group cam follower CF102 in the optical axis direction is restricted. Is done. At this time, a part of the rear portion of the main body portion CF102-a projects rearward of the first group control cam groove CG102, but the half rear portion CF102-br of the head portion CF102-b is inclined rearward in the head guide portion CG102-b. By coming into contact with the surface Kbr102, separation of the first group cam follower CF102 rearward from the first group control cam groove CG102 is restricted. Therefore, similarly to the first and second embodiments, the length of the cam ring 11 in the optical axis direction can be shortened while maintaining the holding of the first group cam follower CF102 in the storage section CG102-x. Further, in the storage section CG102-x, a linear locus following the lead section CG102-c is not traced on the inclined surface Kar102 behind the main body guide portion CG102-a without tracing the movement locus of the first group cam follower CF102. By extending to the rear end of the cam ring 11 as it is, the force from the first group cam follower CF102 is not received in the vicinity of the rear end portion of the inclined surface Kar102, and the structure is excellent in strength.

  FIG. 20 shows a fourth embodiment of the present invention. In this embodiment, the region (the rearmost curve section CG103-x) that is closest to the rear end surface of the cam ring 11 in the first group control cam groove CG103 is the storage section (CG1--) of the first to third embodiments. (x, CG101-x, CG102-x) is not a linear circumferential groove, but a groove with a mountain-shaped locus that protrudes rearward in the optical axis direction. Since the first group cam follower CF1 has the same shape as that of the first embodiment, it is denoted by the same reference numeral.

  The first group control cam groove CG103 includes a wide body guide part (wide groove part) CG103-a in which the main body part CF1-a of the first group cam follower CF1 is fitted, and a narrow head guide part (in which the head part CF1-b is fitted). The main body guide portion CG103-a and the head guide portion CG103-b are connected by a pair of intermediate bottom surfaces Kc103. The main body guide part CG103-a is formed as a single-sided cam groove in which the front inclined surface (opposing wall surface) Kaf103 is left and the rear inclined surface (opposing wall surface) Kar103 does not exist in the rearward curved section CG103-x. . The rear inclined surface Kar103 has two lead sections CG103-c1 and 103 extending diagonally forward from the rearward curved section CG103-x without tracing the locus of the first group cam follower CF1 in the rearmost curved section CG103-x. It extends linearly to the rear end of the cam ring 11 in parallel with the locus of -c2, and communicates with the rear end surface of the cam ring 11. Therefore, a thin fragile portion that receives the force of the first group cam follower CF1 does not exist in the vicinity of the rear end portion of the rear inclined surface Kar103, unlike the thin portion 11nm of the comparative example.

  On the other hand, the head guide portion CG103-b is formed as a double-sided cam groove in which the front inclined surface (opposite wall surface) Kbf103 and the rear inclined surface (opposite wall surface) Kbr103 remain in the rearward curved section CG103-x. Therefore, as shown in FIG. 20, even if the rear part of the main body CF1-a of the first group cam follower CF1 protrudes rearward from the first group control cam groove CG103 (the rear end of the cam ring 11), The engagement between the head guide portion CG103-b and the head portion CF1-b is maintained, and the first group cam follower CF1 is held without being detached from the cam ring 11. The thickness of the rear end wall portion 11d of the cam ring 11 that closes the rear portion of the rear inclined surface Kbr103 in the rearwardly curved section CG103-x is substantially equal to the thickness (T) of the rear end wall portion 11d of the first embodiment. They are consistent and provide sufficient strength.

  As mentioned above, although demonstrated based on illustration embodiment, this invention is not limited to this. For example, in each of the embodiments, the present invention is applied to the rear end portion of the cam ring 11 (the area close to the rear end surface of the cam ring 11 in the first group control cam groove). It is also possible to apply the configuration which is a feature of the present invention to the first group control cam groove in a region close to the front end face of the cam ring 11.

  In addition, the cam groove of each embodiment is such that both the main body guide portion (wide groove portion) and the head guide portion (narrow groove portion) gradually move toward each other as the pair of opposed wall surfaces inside thereof progress in the depth direction. It is set as a pair of inclined surface which narrows a space | interval. From the viewpoint of guiding accuracy with respect to the cam follower and productivity when forming the cam ring (ease of mold removal from the mold), the cam groove may have a trapezoidal cross section having a pair of inclined surfaces. preferable. However, the present invention can also be applied to a feeding cam mechanism or the like in which a part of the opposing wall surface of the cam groove is an orthogonal wall surface orthogonal to the axis of the cam ring. As an example, in the first group control cam groove CG1 in the first embodiment, the inner wall surface of the head guide portion CG1-b may be formed as such an axis orthogonal surface instead of the inclined surfaces Kbf and Kbr. it can. As described above, the basic movement guide of the first group cam follower CF1 by the first group control cam groove CG1 is performed according to the relationship between the main body guide portion CG1-a and the main body portion CF1-a, and therefore the head guide portion CG1- As for b and the head CF1-b, the degree of freedom of the shape should be given within the range where it can be formed as long as it satisfies the function of preventing at least the first group cam follower CF1 from falling off in the storage section CG1-x. Can do. Further, if the guidance accuracy for the first group cam follower CF1 can be ensured, the inner wall surface of the main body guide portion CG1-a as well as the head guide portion CG1-b is replaced with the inclined surfaces Kaf and Kar. The cross-sectional shape of the first group control cam groove CG1 can be a “convex” shape.

  In the illustrated embodiment, the axial length of the front end portion of the cam ring 11 is increased by forming the axis orthogonal surface CF1-d of the first group cam follower CF1 and the axis orthogonal surface CG1-g of the first group control cam groove CG1. Although shortening is also attempted, portions corresponding to the axis orthogonal plane CF1-d and the axis orthogonal plane CG1-g can be omitted in the present invention.

6 Second lens group holding frame 8 Second lens group moving frame 10 Straight guide ring 11 Cam ring 11d Rear end wall 12 Feeding cylinder 21 Image sensor holder 22 Housing 26 Image sensor 40 Detachment control protrusion 51 Third lens group frame 80 Second lens block 100 Shutter block 150 Zoom motor 160 AF motor CF1 CF101 CF102 Group 1 cam follower CF1-a CF101-a CF102-a Main body (large diameter portion)
CF1-b CF101-b CF102-b Head (small diameter part)
CF102-bf Half front part CF102-br Half rear part CF1-c Intermediate annular surface CF2 Two group cam follower CG1 CG101 First group control cam groove CG102 CG103 First group control cam groove CG1-a CG101-a Main body guide part (wide groove part) )
CG102-a CG103-a Main body guide (wide groove)
CG1-b CG101-b Head guide part (narrow groove part)
CG102-b CG103-b Head guide part (narrow groove part)
CG1-c Lead section CG1-d Zoom cam section CG1-e Connection curve section CG1-f End section CG1-x CG101-x CG102-x Storage section (circumferential groove)
CG103-x Last curve section CG2 Second group control cam groove Kaf Kaf101 Front inclined surface (opposite wall surface) of main body guide part
Kaf102 Kaf103 Inclined surface in front of the main body guide part (opposing wall surface)
Kar Kar101 Inclined surface behind main body guide (opposite wall)
Kar102 Kar103 Inclined surface behind main body guide (opposite wall)
Kbf Kbf101 Inclined surface in front of head guide part (opposite wall surface)
Kbf102 Kbf103 Inclined surface in front of head guide part (opposing wall surface)
Kbr Kbr101 Inclined surface behind the head guide (opposite wall)
Kbr102 Kbr103 Inclined surface behind the head guide (opposite wall)
Kc Kc103 Intermediate bottom surface LG1 First lens group LG2 Second lens group LG3 Third lens group ZL Zoom lens barrel

Claims (10)

A cam ring having a cam groove formed on a peripheral surface thereof, a rotatable cam ring, and a movable member having a cam follower that engages with the cam groove and movable in the optical axis direction, wherein the movable member is moved according to the rotation of the cam ring. In the feeding cam mechanism of the lens barrel that moves back and forth in the optical axis direction,
The cam groove has a different position in the depth direction,
A wide groove portion serving as an open-shaped groove that opens in the end surface in a region close to the axial end surface of the cam ring;
A narrow groove portion that maintains a closed groove that does not open to the end face in an area close to the axial end face of the cam ring;
Have
The cam follower has a large-diameter portion that fits into the wide groove portion and a small-diameter portion that fits into the narrow groove portion, and a moving end in the optical axis direction of the moving member with respect to the cam ring, and a part of the large-diameter portion is A feeding cam mechanism for a lens barrel, wherein the lens barrel is disengaged from the cam groove through the opening of the wide groove portion, and the small diameter portion maintains fitting with the narrow groove portion. 2. The feeding cam mechanism for a lens barrel according to claim 1, wherein the wide groove portion is located on the cam ring end surface side of a pair of opposed wall surfaces spaced apart in the groove width direction in the region where the cam groove approaches the cam ring end surface. A lens barrel feeding cam mechanism that forms a single-sided cam groove in which one side does not exist, and the narrow groove portion forms a double-sided cam groove in which a pair of opposing wall surfaces that are separated in the groove width direction remain. 3. The lens barrel feeding cam mechanism according to claim 2, wherein the cam groove approaching area to the cam ring end face is a circumferential groove extending in a direction substantially orthogonal to the axis of the cam ring. mechanism. 3. The lens barrel feeding cam mechanism according to claim 2, wherein the cam groove approaching area to the cam ring end face is a groove portion of a mountain-shaped locus that is convex toward the end face direction of the cam ring. Feeding cam mechanism. 5. The feeding cam mechanism for a lens barrel according to claim 2, wherein, of a pair of opposing wall surfaces of the wide groove portion of the cam groove, one opposing wall surface that does not exist in the one-side cam groove section is A lens barrel feed cam mechanism that extends to the end face of the cam ring along a different path from the other opposing wall surface remaining in the one-side cam groove section. 6. The feeding cam mechanism for a lens barrel according to claim 5, wherein the cam groove has a lead groove section that is inclined with respect to an axis of the cam ring, following the area close to the cam ring end face. The lens barrel feeding cam mechanism in which the one opposing wall surface that does not exist in the groove section extends to the end face of the cam ring substantially parallel to the lead groove section. The lens barrel feeding cam mechanism according to any one of claims 2 to 6, wherein the pair of opposing walls in each of the wide groove portion and the narrow groove portion are gradually spaced apart from each other in the depth direction. A lens barrel feeding cam mechanism that is a pair of inclined surfaces to be narrowed. 8. A feeding cam mechanism for a lens barrel according to claim 7, wherein an intermediate bottom surface portion constituting a bottom surface of the wide groove portion is formed between the pair of inclined surfaces of the wide groove portion and the pair of inclined surfaces of the narrow groove portion. A feeding cam mechanism for the lens barrel. 8. The lens barrel feeding cam mechanism according to claim 7, wherein at least one of the pair of inclined surfaces of the wide groove portion and the narrow groove portion is flush with no step across the wide groove portion and the narrow groove portion. A lens barrel feeding cam mechanism that is a surface. 10. The lens barrel feeding cam mechanism according to claim 1, wherein the lens barrel includes a storage state in which the moving member is positioned at a rearward moving end in the optical axis direction, and the moving member is optically moved. It can be operated in the shooting state that extends forward in the axial direction,
An approaching region of the cam groove to the end face of the cam ring is a feeding cam mechanism for a lens barrel that is a storing section that determines a position of the cam follower in the storing state.

Images