JP2007171675A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel which hardly disengages a cam follower from a cam groove and hardly causes falling-off of the fitting portion of the cam follower and a frame member, when an external force acts. <P>SOLUTION: The lens barrel 1A has a rotating frame 3 having a cam groove 3c and a first group frame 4A provided with a main body portion 4Aa connected by a step 4Ae and a cam follower holding portion 4Ab holding a cam follower 14. When the external force due to dropping or the like acts, a force G0 along a line of action D0 acts on the engaging surface of the cam follower 14 with the cam groove 3c. The line of action D0 passes through on the side of the rotating frame 3 from a point P as a deformation center portion. Since the cam follower 14 is displaced toward the cam groove 3c on the side of the rotating frame 3 by the external force, the cam groove and the cam follower are hardly disengaged from each other. The shaft end portion 14b0 of the shaft portion 14b of the cam follower 14 is located inside from the line of action S0 of the external force and the shaft portion 14b of the cam follower 14 hardly comes off from the first group frame 4A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a lens barrel formed of a frame member having a frame connecting engagement portion such as a cam follower.

  When a lens barrel having a cam follower and a cam groove for connecting the frame members receives an inadvertent external force due to dropping or the like, the external force acts on the engaging portion between the cam follower and the cam groove. In the conventional lens barrel, there is a possibility that the frame member is deformed by the external force and the engaging portion is disengaged. In particular, when the engagement surface of the cam follower with the cam groove has a tapered shape, the engagement portion is likely to come off.

Therefore, the lens barrel disclosed in Patent Document 1 employs a structure in which a deformable hinge groove is provided on the external force acting side of a cam pin (cam follower) that is fixed to a movable cylinder (frame member) and has a tapered surface. ing. When an external force is applied to the tip of the movable cylinder, the hinge groove is elastically deformed, but the cam pin is deformed so as to be displaced toward the cam groove. Therefore, it is possible to obtain a state in which the engaging portion between the cam pin and the cam groove is difficult to come off.
JP 2004-125971 A

  However, in the disclosed technique of the lens barrel of Patent Document 1 described above, there is no description regarding dimensional restrictions on the arrangement of the tapered surface of the cam pin (cam follower) and the hinge groove.

  On the other hand, recent digital cameras are required to be compact, and a smaller lens barrel is also required. Therefore, it is necessary to make the length of the radial protrusion of the cam follower shorter. However, in this case, there is a possibility that a situation in which the configuration according to Patent Document 1 described above cannot be adopted may occur.

  When a metal follower is used as the cam follower, the cam follower is often fixed to the frame member by pressure input. Therefore, a sufficient size is required as the depth of the press-fitting portion. However, as described above, it is desirable to adopt a sufficient press-fitting depth in order to satisfy the demand for miniaturization.

  The present invention has been made to solve the above-described problems. When an external force is applied, the engagement between the cam follower and the cam groove, which is a frame connecting engagement portion that connects the frame members, is released (dropped off). It is an object of the present invention to provide a lens barrel that is difficult to cause, and that is difficult to drop out of a fitting portion with a frame member of a cam follower, and that can be downsized.

  According to a first aspect of the present invention, a lens barrel includes a first frame member having a cam groove, a main body portion, an engagement portion that is formed continuously with the main body portion, and engages with the cam groove. And a second frame member having a holding portion that holds the cam follower including a fitting portion extending from the fitting portion in a state in which the fitting portion is fitted, wherein the engagement portion of the cam follower is The engagement surface of the first frame member with the cam groove is such that the normal line of the engagement surface is higher than the deformation center portion of the main body portion and the holding portion of the second frame member. The insertion portion of the cam follower has a length in which the insertion end portion is positioned inside the holding portion from the deformation center portion. It is inserted in the holding part.

  The lens barrel according to a second aspect of the present invention is the lens barrel according to the first aspect, wherein the holding portion protrudes from a peripheral surface of the main body portion and a projection surface into which the cam follower is fitted, It has a side part which connects between a projection surface and the peripheral surface of the above-mentioned body part.

  A lens barrel according to a third aspect of the present invention is the lens barrel according to the first aspect, wherein the second frame member has a concave groove between the main body portion and the holding portion.

  A lens barrel according to a fourth aspect of the present invention is the lens barrel according to the first aspect, wherein the main body portion is covered with a metal frame except for an end portion connected to the holding portion. .

  A lens barrel according to a fifth aspect of the present invention is the lens barrel according to the first aspect, wherein the holding portion further protrudes from one end surface of the main body portion.

  A lens barrel according to a sixth aspect of the present invention is the lens barrel according to the first aspect, wherein the second frame member has a concave hole between the main body portion and the holding portion.

  The lens barrel according to claim 7 of the present invention is provided in the vicinity of a second frame member having a cam follower, a cam groove engaging with the cam follower, and a retraction direction side of the second frame member of the cam groove. A first frame member provided with a groove, wherein the groove is on a side in the retraction direction in which a normal line of an engagement surface between the cam groove and the cam follower continues through the groove. The first frame member and the first frame member on the feeding direction side are formed so as to pass through the position on the second frame member side rather than the deformation center portion.

  According to the present invention, when an external force is applied, the engagement between the cam follower, which is a frame connecting engagement portion for connecting the frame member, and the cam groove is difficult to be disengaged, and the fitting portion between the cam follower and the frame member falls off. Therefore, it is possible to provide a lens barrel that is less likely to cause a reduction in size.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of the lens barrel of the first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the lens barrel. 3 is an AA enlarged cross-sectional view of FIG. FIG. 4 is an AA enlarged sectional view of FIG. 1 as well, and is an enlarged view showing deformation when an external force is applied along the optical axis. FIG. 21 is a diagram showing a state in which the lens barrel of the present embodiment and each of the embodiments described later received an external force in the optical axis direction due to dropping or the like.

  The lens barrel 1A of the present embodiment is a lens barrel that is incorporated in the camera body 20 (FIG. 21) and can be zoomed by a zoom drive system. 1A and 1B, the lens barrel 1A includes a fixed frame 2 that is fixedly supported by the camera body, and a first frame member that is rotatably supported in the fixed frame 2 and can be inserted and supported. A rotating frame 3, a first group frame 4 </ b> A that is a second frame member that is supported in the rotating frame 3 and holds the first group lens 6, and a second group frame 7 that holds the second group lens 8. And a float key 11 which is supported by the rotary frame 3 and restricts the rotation of the first and second group frames 4A and 7.

  In the description including the following embodiments, the optical axis of the photographing lens (first and second group lenses) is O, the subject side in the optical axis O direction is the front, and the imaging side is the rear.

  The fixed frame 2 is a cylindrical frame member, and is provided with a female helicoid screw 2a and two rectilinear grooves 2b along the optical axis O direction on the inner periphery. The fixed frame 2 incorporates a drive gear 13 having an axial center along the optical axis O direction, and the front end inner peripheral portion has a dustproof, waterproof, and light-shielding function that slides on the outer periphery of the rotary frame 3. A seal ring 16 having the same is inserted.

  The rotating frame 3 is a cylindrical frame member, and a male helicoid screw 3a that engages with the female helicoid screw 2a of the fixed frame 2 and a gear portion 3b that meshes with the drive gear 13 are provided on the outer periphery of the rear end. In addition, two types of cam grooves 3c and 3d (each one is illustrated) that are inclined with respect to the direction of the optical axis O are provided on the inner peripheral portion. The cam grooves 3c and 3d are grooves having inclined surfaces necessary for die cutting during molding (FIG. 3). In addition, a seal ring 17 having a dustproof, waterproof, and light-shielding function that slides on the outer periphery of the first group frame 4A is fitted into the inner peripheral portion of the front end of the rotary frame 3.

  The rotating frame 3 is rotationally driven by the drive gear 13 through the gear portion 3b, and moves forward and backward in the direction of the optical axis O while rotating with respect to the fixed frame 2 by the female helicoid screw 2a.

  The first group frame 4A is a cylindrical resin frame member, and is fitted into the inner peripheral portion of the rotary frame 3 so as to be capable of relative rotation and advance / retreat. The first group frame 4A includes a front body portion 4Aa and a cam follower holding portion 4Ab as a rear holding portion. A lens holding frame 5 is fixed inside the first group frame 4A, and a first group lens 6, a focusing drive unit 9, and a shutter unit 10 are incorporated in the lens holding frame 5 (FIG. 2). .

  The outer periphery of the cam follower holding portion 4Ab forms an outer peripheral surface that protrudes in the radial direction with respect to the outer periphery of the main body portion 4Aa, and serves as a side surface portion that connects the outer periphery of the main body portion 4Aa and the outer periphery of the cam follower holding portion 4Ab. A step portion 4Ae is formed. Therefore, the thickness on the main body part 4Aa side is thinner than the thickness on the cam follower holding part 4Ab side (FIG. 3). A cam follower insertion hole 4h is provided near the stepped portion 4Ae of the cam follower holding portion 4Ab. A cutout portion 4d for inserting the cam follower 15 of the second group frame 7 is disposed on the side of the cam follower insertion hole 4h.

  Further, a straight guide groove 4c along the optical axis O direction in which the float key 11 is slidably fitted to restrict the rotation is provided in the inner peripheral portion of the first group frame 4A, and the inner peripheral portion Is provided with a straight guide groove (not shown) for restricting the rotation of the second group frame 7.

  Three cam followers 14 (only one is shown) fixed to the outer peripheral portion of the cam follower holding portion 4Ab are a shaft portion 14b serving as an insertion portion that is press-fitted into the cam follower insertion hole 4h and fixed, and a cam of the rotating frame 3. The engaging portion 14a is a tapered sliding surface that engages with the groove 3c.

  The second group frame 7 is a cylindrical resin frame member, and is fitted into the inner peripheral portion of the first group frame 4A in a state in which the rotation is restricted and the advancement and retraction are possible. The second group frame 7 holds a second group lens 8 on the inner periphery, and three cam followers 15 are arranged on the outer periphery. The cam follower 15 engages with the cam groove 3d of the rotary frame 3 in a slidable state.

  The float key 11 has two projecting keys 11c extending forward from the annular portion having a central opening in the optical axis O direction, and two guide projections 11b projecting outward from the annular portion. Further, a circumferential guide ring 12 is fixed to the annular portion.

  In the float key 11, the guide ring 12 is fitted into a circumferential guide groove (not shown) of the rotating frame 3 in a relatively rotatable state at the rear end of the rotating frame 3, and the guide protrusion 11 b is inserted into the rectilinear groove 2 b of the fixed frame 2. It is slidably fitted into and assembled. Therefore, when the rotary frame 3 rotates and advances and retreats in the optical axis O direction, the float key 11 moves straight along with the rotary frame 3 in the optical axis O direction in a state where the rotation is restricted by the fixed frame 2.

  The key 11c of the float key 11 is slidably fitted in the guide groove 4c of the first group frame 4A, and the first group frame 4A is restricted from rotating with respect to the fixed frame 2 by the float key 11. In this state, it is inserted into and supported by the rotating frame 3, and moves forward and backward in the optical axis O direction by the cam groove 3 c as the rotating frame 3 rotates. On the other hand, the second group frame 7 is also supported in a state in which the rotation is restricted inside the first group frame 4A, and is moved forward and backward in the direction of the optical axis O by the cam groove 3d of the rotation frame 3.

  When the lens barrel 1A of the present embodiment described above is incorporated in the camera body 20 and the camera is in a non-photographing state, the rotary frame 3 and the first group frame 4A are both in the retracted state, and the fixed frame 2 is carried inside. Therefore, when the drive gear 13 is rotationally driven in a predetermined direction to make the camera ready for photographing, the rotary frame 3 is fed forward from the fixed frame 2 in the optical axis O direction while rotating. At the same time, the first group frame 4 </ b> A is extended to a position where photographing can be performed ahead of the rotation frame 3 in the rotation restricted state. The second group frame 7 moves to a position where photographing can be performed inside the first group frame 4A. Thereafter, the lens barrel 1 </ b> A is driven back and forth to each zooming position by the drive gear 13 as necessary, and photographing is performed.

  In the lens barrel 1A of the present embodiment, when the camera is in a shootable state as described above, the first group frame 4A has moved to the extended position protruding forward. When dropped in the H direction with the side facing down, the front end face of the first group frame 4A hits an obstacle 30 such as the ground as shown in FIG. 21, and the lens barrel 1A is subjected to an external force in the optical axis O direction ( Impact force) F0. The external force F0 is received by the cam follower 14 of the first group frame 4A and the cam groove 3c of the rotating frame 3, and is transmitted to the fixed frame 2 side. The deformation state of the first group frame 4A and the rotating frame 3 around the cam follower and the cam groove at that time will be described below with reference to FIGS.

  As shown in FIG. 3, an external force F0 is applied to the first group frame 4A and the rotary frame 3, and a force G0 inclined with respect to the optical axis O direction acts on the engaging portion 14a which is a tapered sliding surface of the cam follower 14. .

  On the other hand, in the first group frame 4A, as described above, there is a step portion 4Ae between the main body portion 4Aa and the cam follower holding portion 4Ab, and the main body portion 4Aa is thin. When a force G0 acts on the engaging portion 14a of the cam follower 14, the point P0 near the stepped portion 4Ae becomes a deformation center portion due to the force G0, and the cam follower 14 is slightly displaced with the point P0 as the deformation center (FIG. 4). The action line D0 on which the force G0 acts coincides with the normal direction of the engaging portion 14a (engagement surface). In this embodiment, the action line D0 is separated from the point P0 toward the rotary frame 3 side. It passes the distance α0.

  Therefore, the first group frame 4A receives a clockwise (on the top of FIG. 3) moment about the point P0, and the engaging portion 14a of the cam follower 14 moves to the outer diameter side of the first group frame 4A, that is, rotates. It is displaced by elastic deformation in the direction of biting into the cam groove 3c of the frame 3. When the external force F0 acts on the lens barrel 1A in this way, the engaging portion 14a of the cam follower 14 tends to move closer to the cam groove 3c side by deformation of the center of the point P0 of the first group frame 4A. Hard to come off from the groove 3c.

  Further, the shaft end portion 14b0, which is the insertion end portion of the shaft portion 14b of the cam follower 14 press-fitted into the cam follower insertion hole 4h of the first group frame 4A, has a direction in which an external force F0 passing through the point P0 acts (optical axis O). (In a direction parallel to the direction) of the action line S0 (FIG. 3). The total length of the shaft portion is δ1, the length δ2 on the engaging portion side from the action line S0, and the length δ3 on the shaft end side. When the cam follower 14 is pressed, there is a portion C0 where the fitting is loosened in the vicinity of the insertion opening of the cam follower insertion hole 4h (FIG. 4), but there is a portion of the length δ3 up to the shaft end portion 14b0. It is difficult for the portion 14b to come out of the cam follower insertion hole 4h.

  According to the lens barrel 1A of the present embodiment, by adopting the shape described above around the cam follower 14 mounting portion of the first group frame 4A, even when an impact force acts on the first group frame 4A due to dropping or the like, the cam follower 14 and the cam groove 3c of the rotary frame 3 are not easily disengaged, and the risk of the shaft portion 14b of the cam follower 14 falling off from the first group frame 4A is reduced. In particular, the outer diameters of the first group frame 4A and the rotating frame 3 can be made smaller by reducing the separation distance α0 to an allowable dimension while securing the shaft end side length δ3 of the cam follower 14. The lens barrel can be downsized. Further, when the first group frame 4A receives an impact, as described above, the cam follower holding portion 4Ab of the first group frame 4A is elastically deformed so that a part of the impact energy is absorbed, and the actually acting impact force is obtained. There is also an effect of weakening.

Next, the lens barrel of the second embodiment of the present invention will be described with reference to FIGS.
FIG. 5 is an exploded perspective view of the rotary frame and the first group frame constituting the lens barrel of the present embodiment. 6 is an enlarged cross-sectional view taken along the line B-B in FIG. 5. FIG. 7 is an enlarged cross-sectional view taken along the line B-B of FIG. 5, and is an enlarged view showing deformation at the time of external force action along the optical axis.

  The lens barrel 1B of the present embodiment is different from the lens barrel 1A of the first embodiment in the shape around the cam follower mounting portion of the first group frame. The same constituent members and the same shape parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  As shown in FIG. 5, the rotary frame 3 as the first frame member applied to the lens barrel 1B has the same shape as that applied to the first embodiment. The first group frame 4B as the second frame member also includes a front body portion 4Ba and a cam follower holding portion 4Bb which is a rear holding portion, but a concave groove 4Bg is provided between the body portion 4Ba and the cam follower holding portion 4Bb. Is formed. A cam follower insertion hole 4h is disposed near the recessed groove 4Bg, and a notch 4d is provided on the side of the cam follower 14 in the same manner as the first group frame 4A.

  Also in the lens barrel 1B of the present embodiment, when the camera is in a photographing enabled state, the first group frame 4B is moved to the extended position protruding forward. If the camera is dropped in the H direction with the lens barrel side down, the front end surface of the first group frame 4B hits an obstacle 30 such as the ground as shown in FIG. The external force (impact force) F0 in the direction of the optical axis O is received. The external force F0 is received by the cam follower 14 of the first group frame 4B and the cam groove 3c of the rotating frame 3, and is transmitted to the fixed frame 2 side. The deformation state of the first group frame 4B and the rotating frame 3 around the cam follower and the cam groove will be described below with reference to FIGS.

  As shown in FIG. 6, an external force F0 is applied to the first group frame 4B and the rotary frame 3, and a force G0 inclined with respect to the direction of the optical axis O acts on the engaging portion 14a which is a tapered sliding surface of the cam follower 14. .

  On the other hand, as described above, the first group frame 4B has the concave groove 4Bg between the main body portion 4Ba and the cam follower holding portion 4Bb. When a force G0 is applied to the engaging portion 14a of the cam follower 14, the point P0 in the vicinity of the concave groove 4Bg becomes a deformation center due to the force G0, and the cam follower 14 is slightly displaced with the point P0 as the deformation center (FIG. 7). The action line D0 on which the force G0 acts coincides with the normal direction of the engaging portion 14a (engagement surface). In this embodiment, the action line D0 is a distance α0 closer to the rotary frame 3 from the point P0. Through.

  Accordingly, the first group frame 4B receives a clockwise (on the top of FIG. 6) moment around the point P0, and the engaging portion 14a of the cam follower 14 moves to the outer diameter side of the first group frame 4B, that is, rotates. It is displaced by elastic deformation in the direction of biting into the cam groove 3c of the frame 3. When the external force F0 acts on the lens barrel 1B in this way, the engaging portion 14a of the cam follower 14 tends to move closer to the cam groove 3c side by deformation of the center of the point P0 of the first group frame 4B. Hard to come off from the groove 3c.

  Further, the shaft end portion 14b0 at the tip of the shaft portion 14b of the cam follower 14 that is press-fitted into the cam follower insertion hole 4h of the first group frame 4B has a direction (parallel to the optical axis O) in which an external force F0 passes through the point P0. It is inside the action line S0 (FIG. 6). The total length of the shaft portion is δ1, the length δ2 on the engaging portion side from the action line S0, and the length δ3 from the shaft end portion 14b0. When the cam follower 14 is pressed, there is a portion C0 where the fitting is loosened in the vicinity of the insertion opening of the cam follower insertion hole 4h (FIG. 7), but there is a portion of the length δ3 up to the shaft end portion 14b0. It is difficult for the portion 14b to come out of the cam follower insertion hole 4h.

  According to the lens barrel 1B of the present embodiment, the same effects as those of the lens barrel 1A of the first embodiment can be obtained. Particularly in the case of the present embodiment, the outer diameters of the main body portion 4Ba and the cam follower holding portion 4Bb of the first group frame 4B can be made the same diameter.

Next, a lens barrel according to a third embodiment of the present invention will be described with reference to FIGS.
FIG. 8 is an exploded perspective view of the rotary frame and the first group frame constituting the lens barrel of the present embodiment. FIG. 9 is an enlarged cross-sectional view taken along the line CC of FIG. FIG. 10 is an enlarged cross-sectional view taken along the line CC of FIG. 8, and is an enlarged view showing deformation when an external force is applied along the optical axis.

  The lens barrel 1C of this embodiment is different from the lens barrel 1A of the first embodiment in the shape around the cam follower mounting portion of the first group frame. The same constituent members and the same shape parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  As shown in FIG. 8, the rotary frame 3 which is a first frame member applied to the lens barrel 1C has the same shape as that applied to the first embodiment. The first group frame 4C, which is a second frame member, also includes a front body portion 4Ca and a cam follower holding portion 4Cb which is a rear holding portion. The outer diameter portion of the main body portion 4Ca is outside the cam follower holding portion 4Cb. The metal cylindrical frame member 18 is fitted and fixed to the outer diameter portion thereof except for the end portion continuous with the cam follower holding portion 4Cb. In addition, the notch part 4d is provided in the side of the cam follower 14 like the 1st group frame 4A.

  Also in the lens barrel 1C of the present embodiment, when the camera is in a photographing enabled state, the first group frame 4C has moved to the extended position protruding forward. If the camera is dropped in the H direction with the lens barrel side down, the front end surface of the first group frame 4C hits an obstacle 30 such as the ground as shown in FIG. An external force (impact force) F0 in the direction of the optical axis O is received. The external force F0 is received by the cam follower 14 of the first group frame 4C and the cam groove 3c of the rotating frame 3, and is transmitted to the fixed frame 2 side. The deformation state of the first group frame 4C and the rotating frame 3 around the cam follower and the cam groove at that time will be described below with reference to FIGS.

  As shown in FIG. 9, an external force F0 is applied to the first group frame 4C and the rotary frame 3, and a force G0 inclined with respect to the optical axis O direction acts on the engaging portion 14a which is a tapered sliding surface of the cam follower 14. .

  On the other hand, in the first group frame 4C, as described above, the main body 4Ca is covered with the metal cylindrical frame member 18, and the main body 4Ca is not easily deformed. The main body 4Ca is stepped with the cam follower holding portion 4Cb. The thickness is continuous with each other, and the thickness thereof is smaller than that of the cam follower holding portion 4Cb. When a force G0 acts on the engaging portion 14a of the cam follower 14, a point P0 in the vicinity of the step portion of the main body portion 4Ca between the end of the cylindrical frame member 18 and the cam follower holding portion 4Cb is a deformation center portion due to the force G0. Thus, the cam follower 14 is slightly displaced with the point P0 as the deformation center (FIG. 10). The action line D0 on which the force G0 acts coincides with the normal direction of the engaging portion 14a (engagement surface). In this embodiment, the action line D0 is a distance α0 closer to the rotary frame 3 from the point P0. Through.

  Therefore, the first group frame 4C receives a clockwise (centered on FIG. 9) moment about the point P0, and the engaging portion 14a of the cam follower 14 moves to the outer diameter side of the first group frame 4C, that is, rotates. It is displaced by elastic deformation in the direction of biting into the cam groove 3c of the frame 3. Thus, when the external force F0 is applied to the lens barrel 1C, the engaging portion 14a of the cam follower 14 tends to move closer to the cam groove 3c side by deformation of the center of the point P0 of the first group frame 4C. Hard to come off from the groove 3c.

  Further, the shaft end portion 14b0 at the tip of the shaft portion 14b of the cam follower 14 press-fitted into the cam follower insertion hole 4h of the first group frame 4C is in the direction (parallel to the optical axis O) in which the external force F0 passes through the point P0. It is inside the action line S0 (FIG. 9). The total length of the shaft portion is δ1, the length δ2 on the engaging portion side from the action line S0, and the length δ3 from the shaft end portion 14b0. When the cam follower 14 is pressed, C0 is generated in the vicinity of the insertion opening of the cam follower insertion hole 4h (FIG. 9). However, since the portion of the length δ3 to the shaft end portion 14b0 exists, the shaft portion is present. 14b is difficult to come out from the cam follower insertion hole 4h.

  According to the lens barrel 1C of the present embodiment, the same effects as those of the lens barrel 1A of the first embodiment can be obtained. It is particularly suitable when it is necessary to cover the first group frame with a metal frame as an exterior member.

Next, a lens barrel according to a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 11 is an exploded perspective view of the rotary frame and the first group frame constituting the lens barrel of the present embodiment. FIG. 12 is a DD enlarged cross-sectional view of FIG. FIG. 13 is a DD enlarged cross-sectional view of FIG. 11 as well, and is an enlarged view showing deformation at the time of external force action along the optical axis.

  The lens barrel 1D of this embodiment differs from the lens barrel 1A of the first embodiment in the shape around the cam follower mounting portion of the first group frame. The same constituent members and the same shape parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  As shown in FIG. 11, the rotating frame 3 as the first frame member applied to the lens barrel 1D has the same shape as that applied to the first embodiment. The first group frame 4D as the second frame member also includes a front main body portion 4Da and a cam follower holding portion 4Db which is a rear holding portion, and a plurality of cam follower holding portions 4Db are rearward from the end surface of the main body portion 4Da. It is formed so as to protrude.

  Even in the lens barrel 1D of the present embodiment, when the camera is in a photographing enabled state, the first group frame 4D has moved to the extended position protruding forward. If the camera is dropped in the H direction with the lens barrel side down, the front end surface of the first group frame 4D hits an obstacle 30 such as the ground as shown in FIG. An external force (impact force) F0 in the direction of the optical axis O is received. The external force F0 is received by the cam follower 14 fixed to the cam follower holding portion 4Db of the first group frame 4D and the cam groove 3c of the rotating frame 3, and is transmitted to the fixed frame 2 side. The deformation state of the first group frame 4D and the rotating frame 3 around the cam follower and the cam groove at that time will be described below with reference to FIGS.

  As shown in FIG. 12, an external force F0 is applied to the first group frame 4D and the rotary frame 3, and a force G0 inclined with respect to the optical axis O direction acts on the engaging portion 14a which is a tapered sliding surface of the cam follower 14. .

  On the other hand, as described above, the cam follower holding portion 4Db of the first group frame 4D is arranged in a state of protruding from the main body portion 4Da, and therefore when the force G0 acts on the engaging portion 14a of the cam follower 14, the cam follower holding portion 4Db. The point P0 (FIG. 12) of the root portion 4Di of the head becomes the center of deformation due to the force G0, and the cam follower 14 is slightly displaced with the point P0 as the center of deformation (FIG. 13). The action line D0 on which the force G0 acts coincides with the normal direction of the engaging portion 14a (engagement surface). In this embodiment, the action line D0 is a distance α0 closer to the rotary frame 3 from the point P0. Through.

  Therefore, the first group frame 4D receives a clockwise (on the top of FIG. 12) moment around the point P0, and the engaging portion 14a of the cam follower 14 moves to the outer diameter side of the first group frame 4D, that is, rotates. It is displaced by elastic deformation in the direction of biting into the cam groove 3c of the frame 3. When the external force F0 acts on the lens barrel 1D in this way, the engaging portion 14a of the cam follower 14 tends to move closer to the cam groove 3c side by deformation of the center of the point P0 of the first group frame 4D. Hard to come off from the groove 3c.

  Further, the shaft end portion 14b0 at the tip of the shaft portion 14b of the cam follower 14 press-fitted into the cam follower insertion hole 4h of the first group frame 4D is in the direction (parallel to the optical axis O) in which the external force F0 passes through the point P0. Inside the action line S0 (on the side opposite to the cam groove side of the rotating frame 3) (FIG. 12). The total length of the shaft portion is δ1, the length δ2 on the engaging portion side from the action line S0, and the length δ3 from the shaft end portion 14b0. When the cam follower 14 is pressed, there is a portion C0 where the fitting is loosened in the vicinity of the insertion opening of the cam follower insertion hole 4h (FIG. 13), but there is a portion of the length δ3 up to the shaft end portion 14b0. It is difficult for the portion 14b to come out of the cam follower insertion hole 4h.

  According to the lens barrel 1D of the present embodiment, the same effects as those of the lens barrel 1A of the first embodiment can be obtained. In particular, it can be easily applied to a lens barrel having a structure in which the cam follower holding portion of the first group frame needs to be arranged in a state of protruding from the main body portion.

Next, a lens barrel according to a fifth embodiment of the present invention will be described with reference to FIGS.
FIG. 14 is an exploded perspective view of the rotating frame and the first group frame constituting the lens barrel of the present embodiment. FIG. 15 is an EE enlarged sectional view of FIG. FIG. 16 is an enlarged cross-sectional view taken along the line E-E in FIG. 14, and is an enlarged view showing deformation when an external force is applied along the optical axis.

  The lens barrel 1E of the present embodiment differs from the lens barrel 1A of the first embodiment in the shape around the cam follower mounting portion of the first group frame. The same constituent members and the same shape parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  As shown in FIG. 14, the rotary frame 3 as the first frame member applied to the lens barrel 1E has the same shape as that applied to the first embodiment. The first group frame 4E as the second frame member also includes a front body portion 4Ea and a cam follower holding portion 4Eb which is a rear holding portion. The first group frame 4E is provided with a concave hole 4Ej in the vicinity of the front side of the cam follower insertion hole 4h to which the cam follower 14 is fixed. Further, a notch 4d is arranged on the side of the cam follower insertion hole 4h.

  In the lens barrel 1E of the present embodiment as well, when the camera is in a shootable state, the first group frame 4E has moved to the extended position protruding forward. If the camera is dropped in the H direction with the lens barrel side down, as shown in FIG. 21, the front end surface of the first group frame 4E hits an obstacle 30 such as the ground, and the lens barrel 1E An external force (impact force) F0 in the direction of the optical axis O is received. The external force F0 is received by the cam follower 14 fixed to the cam follower holding portion 4Eb of the first group frame 4E and the cam groove 3c of the rotating frame 3, and is transmitted to the fixed frame 2 side. The deformation state of the first group frame 4E and the rotating frame 3 around the cam follower and the cam groove at that time will be described below with reference to FIGS.

  As shown in FIG. 15, an external force F0 is applied to the first group frame 4E and the rotary frame 3, and a force G0 inclined with respect to the optical axis O direction acts on the engaging portion 14a which is a tapered sliding surface of the cam follower 14. .

  On the other hand, as described above, the concave hole 4Ej is arranged in front of the cam follower holding portion 4Eb of the first group frame 4E, and the concave hole 4Ej is provided, so that the force G0 is applied to the engaging portion 14a of the cam follower 14. When acting, the point P0 (FIG. 15) in the vicinity of the bottom of the recessed hole 4Ej becomes the deformation center portion with the maximum distortion due to the force G0, and the cam follower 14 is slightly displaced with the point P0 as the deformation center (FIG. 16). The action line D0 on which the force G0 acts coincides with the normal direction of the engaging portion 14a (engagement surface). In this embodiment, the action line D0 is a distance α0 closer to the rotary frame 3 from the point P0. Through.

  Therefore, the first group frame 4E receives a clockwise (on FIG. 15) moment centered on the point P0, and the engaging portion 14a of the cam follower 14 moves to the outer diameter side of the first group frame 4E, that is, rotates. It is displaced by elastic deformation in the direction of biting into the cam groove 3c of the frame 3. When the external force F0 acts on the lens barrel 1E in this way, the engaging portion 14a of the cam follower 14 tends to move closer to the cam groove 3c side by deformation of the center of the point P0 of the first group frame 4E. Hard to come off from the groove 3c.

  Further, the shaft end portion 14b0 at the tip of the shaft portion 14b of the cam follower 14 press-fitted into the cam follower insertion hole 4h of the first group frame 4E is in the direction in which the external force F0 passing through the point P0 acts (the direction parallel to the optical axis O). It is inside the action line S0 (FIG. 15). The total length of the shaft portion is δ1, the length δ2 on the engaging portion side from the action line S0, and the length δ3 from the shaft end portion 14b0. When the cam follower 14 is pressed, there is a portion C0 where the fitting is loosened in the vicinity of the fitting inlet of the cam follower fitting hole 4h (FIG. 16), but there is a portion of the length δ3 up to the shaft end portion 14b0. It is difficult for the portion 14b to come out of the cam follower insertion hole 4h.

  According to the lens barrel 1E of the present embodiment, the same effects as those of the lens barrel 1A of the first embodiment can be obtained. This is particularly convenient when the cam follower holding part and the main body part of the first group frame need to have the same outer diameter.

Next, a lens barrel according to a sixth embodiment of the present invention will be described with reference to FIGS.
FIG. 17 is an exploded perspective view of the rotary frame and the first group frame constituting the lens barrel of the present embodiment. 18 is an enlarged cross-sectional view taken along line FF in FIG. FIG. 19 is an enlarged cross-sectional view taken along the line F-F in FIG. 17, and is an enlarged view showing deformation when an external force is applied along the optical axis.

  The lens barrel 1F of the present embodiment differs from the lens barrel 1A of the first embodiment in the shape around the cam groove of the rotating frame and the structure around the cam follower of the first group frame. The same constituent members and the same shape parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.

  As shown in FIG. 17, the rotating frame 3F as the first frame member applied to the lens barrel 1F is a rear portion of the cam groove 3c that engages with the cam follower 14 of the first group frame 4F, that is, the first group frame. An inner circumferential groove 3Fe in the circumferential direction is arranged on the 4F retraction direction side. The first group frame 4F as the second frame member also includes a front main body portion and a cam follower holding portion which is a rear holding portion. However, the main body portion and the cam follower have the same outer diameter and no step. A notch 4d is arranged on the side of the cam follower insertion hole 4h.

  Also in the lens barrel 1F of the present embodiment, when the camera is in a photographing enabled state, the first group frame 4F has moved to the extended position protruding forward. If the camera is dropped in the H direction with the lens barrel side down, the front end surface of the first group frame 4F hits an obstacle 30 such as the ground as shown in FIG. An external force (impact force) F0 in the direction of the optical axis O is received. The external force F0 is received by the cam follower 14 fixed to the cam follower holding portion of the first group frame 4F and the cam groove 3c of the rotating frame 3F, and transmitted to the fixed frame 2 side. The deformation state around the cam follower and the cam groove of the first group frame 4F and the rotating frame 3F at that time will be described below with reference to FIGS.

  As shown in FIG. 18, an external force F0 is applied to the first group frame 4F and the rotating frame 3F, and the cam groove 3c with which the engaging portion 14a, which is a tapered sliding surface of the cam follower 14, contacts is inclined with respect to the optical axis O direction. Force G0 'is applied.

  As described above, the inner peripheral groove 3Fe is disposed behind the cam groove 3c of the rotating frame 3F, and the portion of the inner peripheral groove 3Fe is thin, so that a force G0 'acts on the cam groove 3c. A point P0 '(FIG. 18) in the vicinity of the inner circumferential groove 3Fe becomes a deformation center portion due to the force G0', and the cam groove 3c side of the rotating frame 3F is slightly bent with the point P0 'as the deformation center (FIG. 19). The action line D0 'on which the force G0' acts coincides with the normal direction of the cam follower contact surface (engagement surface) of the cam groove 3c. In this embodiment, the action line D0 'is the first group from the point P0'. It passes the separation distance α0 'closer to the frame 4F side.

  Therefore, the cam groove 3c side of the rotating frame 3F receives a clockwise (centered on FIG. 18) moment around the point P0 ', and the cam groove 3c is on the inner diameter side of the rotating frame 3F, that is, the cam groove 3c is The first group frame 4F is displaced by elastic deformation in the direction of biting into the cam follower 14. When the external force F0 acts on the lens barrel 1F in this way, the cam groove 3c tends to move closer to the cam follower 14 due to the deformation of the center of the point P0 'of the rotating frame 3F, so the engagement with the cam follower is released. Hateful.

  According to the lens barrel 1F of the present embodiment, the same effects as those of the lens barrel 1A of the first embodiment can be obtained. In particular, there is no need to change the configuration on the first group frame side, and the applicable range is expanded. The cutout portion 4d of the first group frame 4F is not always necessary. As a modification of the rotating frame 3F, as shown in the perspective view of the rotating frame in FIG. 20, on the front side of the inner peripheral groove 3Fe of the rotating frame 3F and at both ends of the cam groove 3c in the optical axis O direction. When the notch 3Fd is provided, the front portion of the rotating frame 3F is easily deformed, so that a more remarkable effect can be obtained.

  In addition, although lens barrel 1A-1F of each embodiment mentioned above was set as the structure which a rotation frame fits into the outer peripheral side of a 1st group frame, conversely the 1st group frame by the side which has a cam follower is an outer periphery of a rotation frame. The same effect can be obtained by adopting the same configuration as in the case of the present embodiment also for the lens barrel configured to be fitted on the side.

  Moreover, although the connection engaging part of the rotating frame and the first group frame of the lens barrels 1A to 1F of the above-described embodiments is constituted by the cam groove and the cam follower. The present invention is not limited to this, and the same configuration can be applied to other connection engagement portions whose engagement contact surfaces are inclined with respect to the optical axis O, and similar effects can be obtained. it can.

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

  In the lens barrel according to the present invention, when an external force is applied, the engagement between the cam follower, which is a frame connecting engaging portion for connecting the frame member, and the cam groove is unlikely to be disengaged (dropped), and the cam follower with respect to the frame member The lens barrel can be used as a lens barrel that is less likely to drop off the fitting portion and can be downsized.

It is a disassembled perspective view of the lens barrel of 1st embodiment of this invention. It is a longitudinal cross-sectional view of the said lens barrel. It is an AA expanded sectional view of FIG. It is the AA expanded sectional view of FIG. 1, Comprising: It is the figure which expanded and showed the deformation | transformation at the time of the external force action along an optical axis. It is a disassembled perspective view of the rotating frame and the 1st group frame which comprise the lens barrel of 2nd embodiment of this invention. It is BB expanded sectional drawing of FIG. FIG. 6 is an enlarged cross-sectional view taken along the line B-B in FIG. 5, illustrating an enlarged deformation when an external force is applied along the optical axis. It is a disassembled perspective view of the rotating frame and 1st group frame which comprise the lens barrel of 3rd embodiment. It is CC expanded sectional drawing of FIG. It is CC sectional drawing of FIG. 8, Comprising: It is the figure which expanded and showed the deformation | transformation at the time of the external force action along an optical axis. It is a disassembled perspective view of the rotating frame and 1st group frame which comprise the lens barrel of 4th embodiment of this invention. It is DD expanded sectional drawing of FIG. It is DD expanded sectional drawing of FIG. 11, Comprising: It is the figure which expanded and showed the deformation | transformation at the time of the external force action along an optical axis. It is a disassembled perspective view of the rotating frame and 1st group frame which comprise the lens barrel of 5th embodiment of this invention. It is EE expanded sectional drawing of FIG. It is EE expanded sectional drawing of FIG. 14, Comprising: It is the figure which expanded and showed the deformation | transformation at the time of the external force action along an optical axis. It is a disassembled perspective view of the rotating frame and 1st group frame which comprise the lens-barrel of 6th embodiment of this invention. It is FF expanded sectional drawing of FIG. FIG. 18 is an enlarged cross-sectional view taken along the line F-F in FIG. 17, illustrating an enlarged deformation when an external force is applied along the optical axis. It is a perspective view of the rotation frame of the modification with respect to the rotation frame of the lens barrel of FIG. It is a figure which shows the state which received the external force of the optical axis direction by the lens barrel of each embodiment of this invention assembled | attached to the camera main body by dropping etc. FIG.

Explanation of symbols

3,3F
... Rotating frame (first frame member)
3c ... Cam groove 4A, 4B, 4C, 4D, 4E, 4F
... First group frame (second frame member)
4Aa, 4Ba, 4Ca, 4Da, 4Ea
... Main body 4Ab, 4Bb, 4Cb, 4Db, 4Eb
... Cam follower holding part 4Ae ... Step part (side part)
4Bg ... concave groove 4Ej ... concave hole 14 ... cam follower 14a ... cam follower engagement portion 14b ... cam follower shaft portion (insertion portion)
14b0 ... Shaft end (insertion end)
18 ... Metal cylindrical frame member (metal frame)
P0 ... Deformation center part D0, D0 '
... Action line (normal of engagement surface)

Claims (7)

A first frame member having a cam groove;
A main body portion, and a holding portion that is formed continuously with the main body portion, and that holds a cam follower including an engaging portion that engages with the cam groove and a fitting portion that extends from the engaging portion in a state in which the fitting portion is fitted. A second frame member comprising:
Here, the engagement surface of the engagement portion of the cam follower with the cam groove of the first frame member has a normal line to the second frame member. And the insertion portion of the cam follower is formed so that the insertion end of the cam follower has the deformation center. A lens barrel having a length located inside the holding portion from the portion and being fitted into the holding portion.   The holding portion has a protruding surface that protrudes from the peripheral surface of the main body portion and into which the cam follower is inserted, and a side surface portion that connects the protruding surface and the peripheral surface of the main body portion. The lens barrel according to claim 1.   The lens barrel according to claim 1, wherein the second frame member has a concave groove between the main body portion and the holding portion.   The lens barrel according to claim 1, wherein a surface of the main body portion is covered with a metal frame except for an end portion connected to the holding portion.   The lens barrel according to claim 1, wherein the holding portion is formed to protrude further from one end surface of the main body portion.   The lens barrel according to claim 1, wherein the second frame member has a concave hole between the main body portion and the holding portion. A second frame member having a cam follower;
A first frame member having a cam groove engaged with the cam follower and a groove provided in the vicinity of the retraction direction side of the second frame member of the cam groove;
Here, the groove has a normal direction of an engagement surface between the cam groove and the cam follower, and the first frame member on the retraction direction side and the retraction direction side on which the normal line continues through the groove. A lens barrel formed so as to pass through a position closer to the second frame member than a center of deformation of the first frame member.

Images