JP2009042345A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lens barrel capable of preventing a cam follower from falling or rotating and precisely moving a straight advance barrel, which holds a lens and moves in the optical axis direction when making the straight advance barrel move along a cam groove with the cam follower provided to the straight advance barrel. <P>SOLUTION: The lens barrel includes: a straight advance guide member on which the straight advance groove is formed; a cam member on which the cam groove is formed; the cam follower comprising a key part extending in the direction of the groove engaged with the straight advance groove and a roller part engaged with the cam groove; the straight advance barrel which moves in the optical axis direction with the cam follower by relatively moving the straight advance guide member and the cam member. In the lens barrel, the cam follower and the straight advance barrel are connected to each other, the abutting surface of the roller part of the cam follower and the straight advance barrel abut on each other, and at least part of an external part of the abutting surface is larger than a circle inscribed on the cam groove. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens barrel, and more particularly to a structure suitable for preventing a cam follower used in a pay-out lens barrel from falling and preventing the cam follower from rotating from an initial state.

  A structure using a cam member and a rectilinear guide member is known as one of mechanisms for moving a lens holding cylinder holding a lens in the optical axis direction. That is, there is known a technique in which the relative rotation of both is converted into a linear motion through a cam follower and the lens holding cylinder is moved in the optical axis direction (see, for example, Patent Document 1).

  The configuration will be described in detail. First, a cam follower having a roller portion (cylindrical roller) that engages with the cam groove of the cam member and a key portion that engages with the rectilinear groove of the linear guide member, and a lens to which the cam follower is attached are held. The straight cylinder and the straight guide member.

  In the above configuration, when the cam member rotates around the optical axis, the rectilinear cylinder is driven in the optical axis direction according to the cam groove.

  In addition, since the straight cylinder is guided according to the straight groove of the straight guide member, as a result, the straight cylinder is driven in the straight groove direction by the rotation of the cam member.

  In such a lens barrel, since the key part is engaged with a distance in the rectilinear groove direction, the strength against impact and static pressure is higher than when the roller part is engaged with the rectilinear groove.

  However, when the frictional force of the contact surface where the cam follower and the rectilinear cylinder come into contact is small, the positional relationship between the cam follower and the rectilinear cylinder collapses from the initial state when an impact or static pressure acts on the lens barrel.

  As a result, the position of the straight cylinder that holds the lens deviates from the design value, and the optical performance may deteriorate.

  In addition, if the area of the contact surface where the cam follower and the rectilinear cylinder abut is small, the key follower and other members extend in the rectilinear groove direction because the cam follower falls with respect to the rectilinear cylinder when biting is done, such as screw tightening. May interfere.

  On the other hand, in Patent Document 2, a cam follower or a lens holding frame is provided with a convex portion extending in the optical axis direction and a concave portion formed in the other, and sliding and fitting in the optical axis direction to cause the cam follower to fall or rotate. It proposes a lens barrel having a mechanism for preventing this.

Patent Document 3 proposes a lens barrel having a mechanism for preventing the cam follower from falling or rotating by providing a guide member so that the cam follower attached via an elastic arm does not rotate around the optical axis. Yes.
JP 2000-194046 A JP 2004-117398 A JP 2000-193872 A

  In the lens barrel disclosed in Patent Document 2, the rotation and tilting of the cam follower relative to the rectilinear barrel (lens holding frame) can be regulated. However, in the lens barrel of Patent Document 2, the relationship (positioning) between the cam follower and the rectilinear guide member is determined by the convex portion and the concave portion provided on the lens holding frame. There is a possibility that the engagement between the portion (cam follower body) and the straight groove is insufficient. In addition, the cam follower may fall and rotate due to the backlash of the protrusion and the recess.

  In the lens barrel disclosed in Patent Document 3, since the guide member can be attached after the cam follower is attached to the rectilinear advance cylinder, the relationship is not determined before assembly, which is preferable. However, if there is a backlash between the guide member and the cam follower, the optical performance is deteriorated. Further, since the guide member is a separate member, the configuration tends to be complicated.

  The present invention can prevent the cam follower from falling or rotating when the straight cylinder that holds the lens and moves in the optical axis direction is moved along the cam groove via the cam follower provided on the straight cylinder. An object of the present invention is to provide a lens barrel that can move with high accuracy.

The lens barrel of the present invention includes a rectilinear guide member in which rectilinear grooves are formed,
A cam member formed with a cam groove;
A cam follower provided with a key portion extending in the groove direction that engages with the rectilinear groove and a roller portion that engages with the cam groove;
A rectilinear cylinder that moves in the optical axis direction via the cam follower by relative movement of the rectilinear guide member and the cam member;
The cam follower and the rectilinear barrel are connected to each other in a lens barrel provided with
The contact surface of the roller portion of the cam follower is in contact with the rectilinear cylinder, and at least a part of the outer shape portion of the contact surface is larger than a circle inscribed in the cam groove.

  According to the present invention, when the straight cylinder that holds the lens and moves in the optical axis direction is moved along the cam groove via the cam follower provided thereon, the cam follower can be prevented from falling and rotating, A lens barrel that can move the cylinder with high accuracy is obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of an essential part of Embodiment 1 when the lens barrel of the present invention is applied to a lens interchangeable digital single lens reflex camera.

  In FIG. 1, the direction of the lens optical axis (photographing optical axis) AXL is the Z direction, and the direction orthogonal to the lens optical axis AXL is parallel to the imaging surface, and the horizontal direction is the X direction and the vertical direction. The direction is the Y direction.

  Reference numeral 1 denotes a camera body (hereinafter simply referred to as a camera), and 2 denotes an interchangeable lens attached to the camera 1. First, the structure of the camera 1 will be described. In the state shown in FIG. 1, the main mirror 3 is disposed on the optical path of the light beam from the interchangeable lens 2, reflects a part of the light beam, guides it to the finder optical system (7, 8), and transmits the remaining light beam. Make it transparent.

  A sub mirror 4 is disposed behind the main mirror 3, and the light beam transmitted through the main mirror 3 is reflected and guided to the focus detection unit 5. The main mirror 3 and the sub mirror 4 can be retracted from the optical path by a drive mechanism (not shown).

  The focus detection unit 5 includes an AF sensor and has a function of performing focus detection (detection of the focus state of the interchangeable lens 2) by a so-called phase difference detection method.

  The AF sensor includes a separator lens that splits an incident light beam into two, two condenser lenses that re-image each split light beam, a line sensor such as a CCD sensor that photoelectrically converts two imaged subject images, and the like. Consists of The line sensor is arranged in a cross shape so as to detect the image position of the subject in the vertical direction (Y direction) and the horizontal direction (X direction).

  Reference numeral 6 denotes an image sensor composed of a CCD sensor or a CMOS sensor, and a light beam (image) from the interchangeable lens 2 forms an image on the light receiving surface (imaging surface) of the image sensor 6. The imaging element 6 photoelectrically converts the formed subject image and outputs an imaging signal. The exposure amount of the image sensor 6 is controlled by an electronically controlled focal plane shutter (not shown).

  The finder optical system has a pentaprism 7 and an eyepiece lens 8.

  Reference numeral 9 denotes a display panel, which has a function of displaying an image output from a signal processing unit (not shown) that receives a signal from the image sensor 6 and various other shooting information.

  The interchangeable lens 2 includes a first lens unit 100 as a focus and variable power lens, a second lens unit 101 as an anti-vibration lens, and third and fourth lens units 102 and 103 as variable power lenses in order from the subject side. is doing. The aperture unit 104 is disposed in the group of the third lens unit 102 and adjusts the amount of light passing through the interchangeable lens 2 and reaching the camera 1 side. The lens units 100 to 103 and the aperture unit 104 constitute a photographing optical system.

  The first lens unit (focus lens) 100 receives the driving force from the gear unit 42, moves on the optical axis AXL, and performs focus adjustment.

  The first, third, and fourth lens units (magnification lenses) 100, 102, and 103 move on the lens optical axis AXL by the operation force of the photographer being transmitted by a transmission mechanism (not shown), and the magnification is varied. Perform (zooming).

  Next, the structure of the lens barrel of the interchangeable lens 2 will be described in detail.

  Reference numeral 21 denotes a first fixed cylinder (straight guide member) for attaching the projection 21a for preventing the cam cylinder 22 from moving in the optical axis direction and guiding the rotation around the optical axis, and the second group lens barrel 35. The attaching part 21b is provided.

  Further, the first fixed barrel 21 includes rectilinear grooves 21c-1 to 21c-3 (21c-2 and c-3 are not shown) for guiding the third group barrel 36 and the fourth group barrel 37 in a straight line. In addition, the first fixed cylinder 21 has a guide groove 21 d that bayonet-fits with the projection 23 a of the zoom operation ring 23 and guides the rotation of the zoom operation ring 23 around the optical axis.

  In addition, an attachment portion 21e for attaching a circuit board (not shown), an attachment portion 21f for attaching the mount 41, and an attachment portion (not shown) of the second fixed cylinder 24 are provided, and the first fixed cylinder 21 and the second fixed cylinder 21 are fixed. The cylinder 24 is fixed by a method such as fastening. In the following description, there are cases where symbols are omitted for convenience (22c-1 is changed to 22c).

  Reference numeral 22 denotes a cam cylinder. The cam barrel 22 includes cam grooves 22b-1 to 22b-3 (22b-2, b-3 not shown) and a fourth group barrel 37 for guiding the movement of the third group barrel 36 in the optical axis direction. Cam grooves 22c-1 to 22c-3 (22c-2, c-3 not shown) for guiding the movement in the optical axis direction.

  Further, the cam barrel 22 includes cam grooves 22d-1 to 22d-3 (22d-2, d-3 not shown) for guiding the movement of the rectilinear barrel 26 in the optical axis direction, and the second group barrel 35. It has a hole (not shown) that allows adjustment of the mounting part.

  Further, the cam cylinder 22 is engaged with guide elongated holes 22 e-1 to 22 e-3 (22 e-2, 22 e-3 not shown) that engage with the guide protrusion 21 a of the first fixed cylinder 21 and the zoom operation ring 23. An attachment portion (not shown) of a connecting member (not shown) to be mated is provided.

  Reference numeral 23 denotes a zoom operation ring, which is engaged with the guide groove 21d of the first fixed cylinder 21 to guide the rotation of the zoom operation ring 23 around the optical axis, and the cam cylinder 22 along with the rotation of the zoom operation ring 23. And an engaging portion (not shown) of a connecting member (not shown) for connecting and rotating.

  Reference numeral 24 denotes a second fixed cylinder, which is fixed to the first fixed cylinder 21 by fastening or the like. The second fixed cylinder 24 is bayonet-fitted with the projection 25a of the focus ring 25 and guides the rotation of the focus ring 25 around the optical axis, and a stopper hole for preventing the cam cylinder 22 from rotating ( And a rotary shaft bearing (not shown) of the output gear of the gear unit 42.

  Reference numeral 25 denotes a focus ring, which is fitted with the guide groove 24a of the second fixed cylinder 24 so that the protrusions 25a-1 to 25a-3 (25a-2 and a-3 are rotatable around the optical axis). (Not shown).

  Furthermore, the focus ring 25 engages with the groove portions 25b-1 to 25b-3 (25b-2, b-3 not shown) that engage with the protrusions 27a of the female helicoid cylinder 27, the output gear of the gear unit 42, and the focus ring 25. A gear portion (not shown) for rotating around the optical axis is provided.

  In addition, there is a reinforcing ring 30 that suppresses deformation in a direction substantially perpendicular to the optical axis of the focus ring 25, and is integrated with the focus ring 25 by a method such as snap-fit coupling, adhesive fixing, or fastening of the focus ring 25 and the cover member 31. Retained.

  The reinforcing ring 30 is made of a material having higher rigidity than the focus ring 25.

  Reference numeral 26 denotes a rectilinear cylinder having helicoid grooves 26a-1 to 26a-3 which are helicoid-coupled to the female helicoid cylinder 27 and formed with a predetermined lead. The rectilinear cylinder 26 includes contact surfaces 26b-1 to 26b-3 (26b-2 and b-3 are not shown) that contact the contact surface 28c of the cam follower 28. The rectilinear cylinder 26 is fixed (coupled) to the cam follower 28 and its abutting surface 28c by screws 44.

  A female helicoid cylinder 27 includes protrusions 27a-1 to 27a-3 (27a-2, a-3 not shown) that engage with the guide groove 25b of the focus ring 25. Furthermore, helicoid coupling with the straight cylinder 26 and helicoid protrusions 27b-1 to 27b-3 formed with predetermined leads, and mounting holes (not shown) for fastening the front frame 29 are provided.

  Reference numeral 29 denotes a front frame which includes a seat (not shown) for fastening to the first group barrel 34. Further, the front frame 29 has a screw portion 29a for mounting accessories such as a filter and a flange portion 29b for mounting accessories such as a hood.

  The front frame 29 and the first group barrel 34 are fastened through a rubber member (not shown), and it is difficult to transmit a force to the first group barrel 34 when an impact or static pressure is generated on the front frame 29. Has been taken.

  Reference numeral 32 denotes an annular thin plate that suppresses entry of dust from the outside.

  Reference numeral 33 denotes an exterior ring, which is a cover member that covers internal parts for decoration.

  Reference numeral 34 denotes a first group barrel, which includes a seat (not shown) for fastening with the female helicoid cylinder 27 and a holding portion 34 a that holds the first group lens 100.

  Reference numeral 35 denotes a second group barrel, a fitting shaft portion 35a that fits the first fixed barrel 21, a shift barrel 35b that corrects camera shake by shifting in a plane perpendicular to the optical axis, and a shift mirror A driving member 35c for driving the cylinder 35b and a holding portion 35d for holding the second group lens 101 are provided.

  Reference numeral 36 denotes a third group barrel, which includes a holding portion 36 a that holds the third group lens 102. Further, the third group barrel 36 is engaged with the rectilinear groove 21c of the first fixed barrel 21 and the cam groove portion 22b of the cam barrel 22 to guide the third group barrel 36 in the optical axis direction. 1 to 38-3 of mounting portions 36b-1 to 36b-3 (36b-2, b-3 not shown). In addition, it has a mounting portion (not shown, usually fixed by snap-fit coupling or fastening with screws) of the diaphragm device 39. The cam followers 38-2 and 38-3 and the attachment portions 36b-2 and 36b-3 are not shown.

  The diaphragm device 39 is disposed in the group of the third group lens barrel 36, and includes a plurality of diaphragm blades 39a, a drive member 39b, and a cover member 39c.

  Reference numeral 37 denotes a fourth group lens barrel, which includes a holding portion 37 a that holds the fourth group lens 103. Further, the fourth group barrel 37 is fitted into the rectilinear groove 21c of the first fixed barrel 21 and the cam groove portion 22c of the cam barrel 22 to guide the fourth group barrel 37 in the optical axis direction. It has 1 to 40-3 attachment portions 37b-1 to 37b-3. The cam followers 40-2 and 40-3 and the mounting portions 37b-2 and 37b-3 are not shown.

  A mount member 41 includes an opening 41a, a flange 41b for attachment to the camera body, and a seat 41c for fastening to the first fixed cylinder 21.

  42 is a gear unit for rotating the focus ring 25 around the optical axis, and includes a drive source (not shown), a plurality of gear portions (42a), and an output gear (not shown) driven by being decelerated by them. Become.

  The output gear meshes with the gear portion of the focus ring 25. The drive source and the electric circuit board are connected by a flexible printed circuit board or the like, and the drive source is driven by a drive signal from the electric circuit.

  The gear unit 42 is provided with an unillustrated intermittent mechanism, and the automatic focusing and manual focusing are switched by the mechanism.

  One end of the flexible printed board is connected to the diaphragm device 39 and the other is connected to the electric circuit board. The diaphragm blade 39a is driven by a drive signal from the electric circuit.

  Furthermore, the other flexible printed circuit board has one end connected to the driving device 35c of the second group barrel 35 and the other connected to the electric circuit board. The shift barrel 35b is driven by a drive signal from the electric circuit.

  A contact member 43 has a contact portion 43a having one end connected to the electric circuit board, and contacts the contact portion of the camera body when it is attached to the camera body so as to transmit information to the camera body. It has become.

  In addition, although not shown, it has an electric circuit board that performs various driving operations in the lens and information transmission processing with the camera.

  In a lens barrel having such a configuration, when a release button (not shown) is operated, after the autofocus and exposure determination operations, the image sensor is exposed and the acquired image is recorded.

  The above is description of each member.

  Next, the interrelationships of main parts related to the present invention will be described.

  FIG. 2 is an enlarged view of a part of the lens barrel of FIG. 1, and shows a cross-sectional view of one cam follower 28 and a related main part as an example among the plurality of cam followers 28, 38, 40. The cam follower 28 has a roller part 28 a that engages with the cam groove 22 d of the cam cylinder 22 and a key part 28 b that engages with the rectilinear groove 21 c of the first fixed cylinder 21.

  Further, the roller portion 28a of the cam follower 28 is provided with a contact surface 28c (a shaded portion in FIG. 3) that contacts the contact surface 26b of the rectilinear cylinder 26. The straight cylinder 26 and the cam follower 28 are fixed by fastening with the screw 44.

  The contact surface 28c has a rough surface so that the friction coefficient is higher than that of a smooth surface.

  The key portion 28b and the contact portion 28c are an integral member and are made of a material having high rigidity such as metal. The roller portion 28a is made of a material having good slidability such as resin, and is formed by performing insert molding on the integral member. Further, the shape of the roller portion 28a and the integral member has a structure in which a slight step is provided in the range engaging with the cam groove 22d (the outer diameter on the roller portion 28a side is large) to obtain impact resistance. This structure allows the cam groove 22d to abut against the integral member when the roller portion 28a is deformed due to impact or dropping, and prevents the sliding performance from being deteriorated due to plastic deformation or dents of the roller portion 28a. ing. In a normal use state, the cam groove 22d and the roller portion 28a are engaged with each other, so that good slidability can be obtained.

    Next, the function of the cam follower 28 will be described. When the zoom operation ring 23 is operated, a connecting member (not shown) engaged with the zoom operation ring 23 transmits rotation to the cam barrel 22. As the cam cylinder 22 rotates, the rectilinear cylinder 26 moves through the cam follower 28 while following the relative relationship between the rectilinear groove 21c and the cam groove 22d. That is, the rectilinear cylinder 26 and the cam member 22 move relative to each other. As a result, the rectilinear cylinder 26 is extended in the optical axis direction. As a result, the rectilinear cylinder 26 holding the lens is driven in the optical axis direction.

  FIG. 3 is an explanatory view showing the shape of the cam follower 28 according to the present embodiment. In the present embodiment, at least a part of the outer shape of the contact surface 28 c provided on the roller portion 28 a of the cam follower 28 is made larger than a circle inscribed in the cam groove 22 d of the cam cylinder 22 (broken line in FIG. 3). Yes. As a result, the cam follower 28 is less likely to bite when the cam follower 28 is fastened to the rectilinear cylinder 26, and the cam follower can be prevented from falling.

  In this embodiment, the key portion 28b and the contact portion 28c are made of metal, and the roller portion 28a is made of resin. However, the key portion, the contact portion, and the roller portion may be integrated members.

  In this example, the shape of the contact surface 28c of the cam follower 28 in the lens barrel of the first embodiment is changed as shown in FIG. A specific feature of the present embodiment is that the outer shape of the contact surface 28c of the cam follower 28 is formed along the boundary of a range formed by overlapping the locus of the cam groove 22d at each intersection angle.

  Furthermore, a protrusion 28d having a spike shape, a conical shape, a convex shape or the like is provided on the contact surface 28c. The protrusions may be provided on the contact surface 26b side of the rectilinear cylinder 26, or may be provided on both sides. Further, the shape and the number of the protrusions 28d are not limited to those in FIG.

  Since the contact surface 28c is made of a material having high rigidity as described above, the shape formed on the contact surface 28c (for example, the protrusion in this embodiment) is not easily deformed, and the function of the shape is exhibited. There is an advantage that it is easy.

  FIG. 5 is a diagram for explaining the outer shape of the contact surface 28c. FIG. 5 shows the locus of the cam groove 22d viewed from the cam follower 28 side when the cam follower 28 moves along the cam groove 22d. In the figure, 22d-1-1 has the largest crossing angle among the crossing angles in each region of the cam groove 22d, and 22d-1-2 has the smallest crossing angle.

  In this embodiment, the outer shapes 28c1 and 28c2 that engage with the cam groove 22d of the contact surface 28c are formed along the boundary of the range formed by matching the locus of the cam groove 22d. As a result, the cam follower 28 can be incorporated into the cam groove 22d of the roller portion 28, and the area of the contact surface 28c is made as large as possible.

  The cam follower 28 is tilted when the cam follower 28 and the rectilinear cylinder 26 are fastened by making the area of the contact surface 28c as large as possible (for example, larger than the area of the inscribed circle 28d) as in this embodiment. It becomes easier to suppress than in Example 1.

  Further, by providing one or more spike-shaped, convex-shaped, conical-shaped, or cylindrical-shaped projections 28d on the contact surface 28c, the cam follower 28 can be prevented from rotating during or after the cam follower 28 and the rectilinear cylinder 26 are fastened. Is demonstrated.

  Therefore, compared with the case where the rotation is stopped before fastening, the engagement relationship between the key portion 28b of the cam follower 28 and the rectilinear cylinder 21c is less likely to be unstable when considering the equal difference in the rectilinear groove 21c.

  In this example, the roller portion 28a of the cam follower 28 in the lens barrel in the first embodiment is changed as shown in FIG. Specifically, the outer shape of the contact surface 28c of the cam follower 28 is a shape along the boundary of a range formed by overlapping the locus of the cam groove at each intersection angle (same as in the second embodiment), and The surface of the contact surface 28c is a rough surface.

  The surface roughened and roughened may be the contact surface 26b of the rectilinear cylinder 26, or both.

  Further, as shown in FIG. 6, the contact surface may not be all rough but may be a part. With such a configuration, the cam follower 28 and the rectilinear cylinder 26 can be satisfactorily tilted and prevented from rotating as in the second embodiment.

  As described above, according to the above-described embodiments, a part of the outer shape of the abutting surface 28c where the cam follower 28 and the rectilinear cylinder 26 abut is made larger than the inscribed circle of the cam groove. Thereby, for example, the area of the contact surface can be increased. Further, by providing the protrusion 28d on the contact surface, the cam follower 28 provided on the straight cylinder 26 can be effectively prevented from falling or rotating.

  In each of the above embodiments, the cam follower 28 is used as a part of the zoom mechanism, but the present invention is not limited thereto. For example, a cam follower may be used as part of the focus mechanism.

  Further, in the present embodiment, the lens barrel of the interchangeable-lens digital single-lens reflex camera has been described. However, the present invention is similarly applied to a lens barrel of a digital camera on a lens-integrated side, and further a video camera. Can do.

Sectional drawing of Example 1 of a lens interchangeable digital single-lens reflex camera and a lens barrel Enlarged view of the main parts related to the cam follower and its surroundings in Fig. 1 Explanatory drawing of the cam follower 28 of FIG. Explanatory drawing of the cam follower of Example 2 Explanatory drawing of the shape of the contact surface 28c of the cam follower in Example 2. FIG. Explanatory drawing of the cam follower of Example 3

Explanation of symbols

1: Camera 2: Interchangeable lens (lens barrel)
3: Main mirror 4: Sub mirror 5: Focus detection unit 6: Image sensor 7: Penta prism 8: Eyepiece lens 9: Display panel 100: First lens unit 101: Second lens unit 102: Third lens unit 103: Fourth Lens unit 104: Diaphragm unit 21: First fixed cylinder 22: Cam cylinder 23: Zoom operation ring 24: Second fixed cylinder 25: Focus ring 26: Straight advance cylinder 27: Female helicoid cylinder 28: Cam follower 29: Front frame 30: Reinforcement Ring 31: cover member 32: annular thin plate 33: exterior ring 34: first group barrel 35: second group barrel 36: third group barrel 37: fourth group barrel 38: third group cam follower 39: aperture Device 40: fourth group cam follower 41: mount member 42: gear unit 43: contact member 44: screw (for fastening the straight cylinder 26 and the cam follower 28)

Claims (4)

A rectilinear guide member formed with rectilinear grooves;
A cam member formed with a cam groove;
A cam follower provided with a key portion extending in the groove direction that engages with the rectilinear groove and a roller portion that engages with the cam groove;
A rectilinear cylinder that moves in the optical axis direction via the cam follower by relative movement of the rectilinear guide member and the cam member;
The cam follower and the rectilinear barrel are connected to each other in a lens barrel provided with
The lens barrel characterized in that the contact surface of the roller portion of the cam follower is in contact with the rectilinear cylinder, and at least a part of the outer shape portion of the contact surface is larger than a circle inscribed in the cam groove. . The lens barrel according to claim 1, wherein an outer shape of the contact surface is a shape along a boundary of a range formed by overlapping the locus of the cam groove at each intersection angle. The lens barrel according to claim 1, wherein the contact surface is a rough surface. The lens barrel according to claim 1, wherein a protrusion is provided on the surface of the contact surface.

Images