JP7189710B2 - zoom lens barrel - Google Patents

Description

The present invention relates to a zoom lens barrel.

Conventionally, as a zooming mechanism in a zoom lens barrel, a first barrel having a cam follower and a second barrel having a cam groove are used, and the cam follower is engaged with the cam groove. A configuration is known in which the first lens barrel is advanced and retracted by rotating the first lens barrel with respect to the second lens barrel.

If such a zoom lens barrel is accidentally dropped, the cam follower may fall out of the cam groove, or the cam follower may collide with the edge of the cam groove, resulting in damage or other deformation of the periphery of the cam groove. do. If the cam groove is deformed, smooth zooming cannot be performed.

On the other hand, in Patent Document 1, a cam pin and an anti-dropout pin of the same shape provided on a drive frame are engaged with a cam groove and an anti-dropout groove provided on the cam frame, respectively. is disclosed to prevent the dropout from the cam groove.

JP 2005-128188 A

However, in the configuration described in Patent Literature 1, it is necessary to add a new fall prevention pin, which increases the number of parts.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a zoom lens barrel capable of maintaining a smooth zooming operation without increasing the number of parts and even when an impact such as a drop occurs. The purpose is to

A zoom lens barrel of the present invention includes a sliding barrel, a rotating barrel provided on one side in the radial direction of the sliding barrel, and a barrel member provided on the other side in the radial direction of the sliding barrel. The sliding cylinder has a first piece member projecting to one side in the radial direction and a second piece member projecting to the other side in the radial direction, and the rotary cylinder has a cam into which the first piece member is inserted. A groove is formed in the cylindrical member, and a groove into which the second piece member is inserted is formed in the cylindrical member. By rotating the rotating barrel with respect to the cylindrical member, the sliding barrel is extended in the optical axis direction. In the lens barrel, the slide barrel has a protruding portion protruding to the other side in the radial direction of the second top member, and the rotary barrel is formed with auxiliary cam grooves in addition to the cam grooves, It is characterized in that the projecting portion of the second piece member is inserted into the auxiliary cam groove.

According to the present invention having the above configuration, even when the sliding cylinder is subjected to an impact, the projecting portion of the second link member collides with the edge of the auxiliary cam groove, and the first link member collides with the cam groove. reduce or eliminate the impact when As a result, it is possible to prevent damage to the first top member or the cam groove and maintain smooth zooming. Moreover, since the projecting portion of the second piece member is used, there is no need to provide a new member, and an increase in the number of members can be prevented.

Further, in the present invention, preferably, the auxiliary cam groove has a shape having the same trajectory as the cam groove.
According to the present invention configured as described above, it is possible to maintain smooth zooming and to easily secure a space for forming the auxiliary cam groove.

Also, in the present invention, preferably, the first link member has a roller made of an elastic material, the roller is inserted into the cam groove, and the diameter of the roller is substantially equal to the width of the cam groove.

According to the present invention having the above configuration, even when an impact is applied to the slide cylinder, the roller of the first link member is elastically deformed. As a result, it is possible to more reliably prevent damage to the first link member or the cam groove.

Also, in the present invention, preferably, the protruding portion of the second piece member enters into the auxiliary cam groove with a gap formed between it and the side surface of the auxiliary cam groove.

According to the above-described configuration of the present invention, during zooming, the sliding cylinder is guided by the first link member and the cam groove, so smooth zooming operation can be maintained. When an impact is applied to the slide cylinder and the roller of the first link member is elastically deformed, it abuts against the side of the auxiliary cam groove of the second link member, damaging the first link member or the cam groove. can be prevented.

Also, in the present invention, preferably, the material of the protrusion is harder than the material of the roller.
According to the present invention having the above configuration, when the second link member comes into contact with the side portion of the auxiliary cam groove when an impact is applied, the impact acting on the roller becomes extremely small, thereby preventing damage to the roller. be able to.

According to the present invention, it is possible to provide a zoom lens barrel that can maintain a smooth zooming operation without increasing the number of parts and even when an impact occurs due to a drop or the like.

FIG. 2 is a vertical cross-sectional view along the optical axis showing the zoom lens barrel of the first embodiment, showing a wide-angle state; FIG. 2 is a longitudinal sectional view along the optical axis showing the zoom lens barrel of the first embodiment, FIG. 2 showing a telephoto state; 2 is a perspective view showing an inner fixed barrel and a first rotating barrel of the zoom lens barrel shown in FIG. 1; FIG. 2 is a perspective view showing a sliding barrel, an outer barrel, a second rotating barrel, and a fixed barrel in the zoom lens barrel shown in FIG. 1; FIG. 2 is an enlarged sectional view showing a cam follower of a sliding barrel of the zoom lens barrel shown in FIG. 1; FIG. 2 is a cross-sectional view showing an enlarged rectilinear coma of a sliding barrel of the zoom lens barrel shown in FIG. 1; FIG.

An embodiment of the zoom lens barrel of the present invention will be described in detail below with reference to the drawings.
1 and 2 are longitudinal sectional views along the optical axis showing the zoom lens barrel of the first embodiment, FIG. 1 showing the wide-angle state and FIG. 2 showing the telephoto state.
As shown in FIGS. 1 and 2, the lens barrel 1 of this embodiment includes a first lens group A, a second lens group B, a third lens group C, a fourth lens group D, and a fifth lens group E. Prepare. The fourth lens group D includes a shift lens group that is shifted in a direction orthogonal to the optical axis for camera shake prevention.

A zoom lens barrel 1 includes a mount 2 attached to a camera body, an outer fixed barrel 4 and an inner fixed barrel 6 integral with the mount 2, a first rotary barrel 10 disposed inside the inner fixed barrel 6, have The outer fixed barrel 4 is constructed by connecting a rear outer fixed barrel 4A on the imaging side and a front outer fixed barrel 4B on the object side. A zoom operation ring 22 is rotatably arranged on the outer periphery of the front outer fixed barrel 4B. A focus operation ring 20 is rotatably arranged on the outer periphery of the rear outer fixed barrel 4A.

3 is a perspective view showing an inner fixed barrel and a first rotating barrel of the zoom lens barrel shown in FIG. 1. FIG. As shown in the figure, the inner fixed barrel 6 is formed by connecting a front cylindrical portion 6A on the subject side and a rear cylindrical portion 6B on the imaging side. The front cylindrical portion 6A has a larger diameter than the rear cylindrical portion 6B, and the front cylindrical portion 6A and the rear cylindrical portion 6B are connected in a stepped manner. The first rotary barrel 10 is formed by connecting a front cylindrical portion 10A on the subject side, a rear cylindrical portion 10C on the imaging side, and an intermediate cylindrical portion 10B between the front cylindrical portion 10A and the rear cylindrical portion 10C. . The front cylindrical portion 10A has a larger diameter than the intermediate cylindrical portion 10B, and the front cylindrical portion 10A and the intermediate cylindrical portion 10B are connected in a stepped manner. The portion 10B and the rear cylindrical portion 10C are connected stepwise.

Further, as shown in FIGS. 1 and 2 , a second rotating barrel 8 is arranged outside the inner fixed barrel 6 , and a sliding barrel 12 is arranged outside the second rotating barrel 8 . An outer cylinder (cylinder member) 14 is arranged outside the sliding cylinder 12 and inside the front outer fixed cylinder 4B. The first rotating barrel 10 and the second rotating barrel 8 are connected at their distal ends, and the first rotating barrel 10 and the second rotating barrel 8 move forward and backward while rotating in conjunction with each other.

4 is a perspective view showing a sliding barrel, an outer barrel, a second rotating barrel, and a fixed barrel in the zoom lens barrel shown in FIG. 1. FIG.
A cam follower 8</b>D is erected on the inner surface of the image forming side end of the second rotary barrel 8 . A cam groove 6a is formed in the front cylindrical portion 6A of the inner fixed barrel 6 and is inclined in a predetermined direction in the circumferential direction toward the subject. The cam follower 8</b>D of the second rotary barrel 8 is fitted (engaged) with the cam groove 6 a of the inner fixed barrel 6 . As a result, when the zoom operation ring 22 is rotated, the first rotary barrel 10 and the second rotary barrel 8 are rotated with respect to the inner fixed barrel 6 in conjunction with the zoom operation ring 22 to advance and retreat in the optical axis direction. .

A linear piece 14A is formed on the outer surface of the rear end portion of the outer cylinder 14, and this linear piece 14A fits into a vertical groove extending in the optical axis direction formed on the inner surface of the front outer fixed barrel 4B of the outer fixed barrel 4. It is crowded. As a result, the outer cylinder 14 is restrained from rotating and can advance and retreat in the front-rear direction.

The slide cylinder 12 has a rectilinear piece (second piece member) 12A formed on the outer surface of the rear end thereof. I'm stuck. As a result, the sliding cylinder 12 is restrained from rotating and can move back and forth with respect to the outer cylinder 14 .

A cam groove 8A is formed on the outer surface of the second rotary barrel 8 so as to extend in a predetermined circumferential direction at an angle toward the subject. A cam follower (first piece member) 12B erected on the inner surface of the rear end of the slide cylinder 12 is fitted into the cam groove 8A. A lateral groove 8B extending in the circumferential direction is formed in the rear end portion of the second rotary barrel 8. As shown in FIG. A piece 14C erected on the inner surface of the rear end portion of the outer cylinder 14 is fitted in the lateral groove 8B. Further, an auxiliary cam groove 8C having the same shape as the cam groove 8A, that is, having the same trajectory is formed between the cam grooves 8A adjacent in the circumferential direction. The cam grooves 8A and the auxiliary cam grooves 8C are provided at regular intervals in the circumferential direction.

FIG. 5 is a cross-sectional view showing an enlarged cam follower of the sliding barrel of the zoom lens barrel shown in FIG. FIG. 6 is a cross-sectional view showing an enlarged rectilinear coma of the sliding barrel of the zoom lens barrel shown in FIG. As shown in FIG. 5, the cam follower 12B of the slide cylinder 12 includes a screw 60, a cam follower shaft 62, and a roller 64. As shown in FIG. The cam follower shaft 62 is disc-shaped and has a through hole 62A formed in its center. In the cam follower 12B, the cam follower shaft 62 is arranged at a position corresponding to the through hole 12C on the inner surface of the slide cylinder 12, the screw 60 is inserted through the through hole 12C from the outside of the slide cylinder 12, and the tip of the screw 60 is attached to the cam follower shaft 62. is attached to the sliding cylinder 12 by screwing it into the through hole 62A. A tip portion 62B of the cam follower shaft 62 has a smaller diameter than other parts, and a roller 64 is rotatably attached to this tip portion 62B. The roller 64 is made of an elastically deformable material such as rubber. In the attached state of the cam follower 12B, the head of the screw 60 does not protrude from the outer surface of the sliding cylinder 12, and the cam follower shaft 62 and roller 64 protrude from the inner surface. The outer diameter of the roller 64 of the cam follower 12B is substantially equal to the width of the cam groove 8A of the second rotary cylinder 8. As shown in FIG. The cam follower 12B is engaged with the cam groove 8A while the roller 64 is in contact with the inner surface of the cam groove 8A.

As shown in FIG. 6, the rectilinear piece 12A of the slide cylinder 12 includes a screw 70, a piece member 72, and a nut member 74. As shown in FIG. The piece member 72 is disc-shaped and has a through hole 72A formed in the center. In the rectilinear piece 12A, the piece member 72 is arranged at a position corresponding to the through hole 12D of the outer surface of the sliding cylinder 12, and the screw 70 is inserted through the through hole 72A of the piece member 72 and the through hole 12D of the sliding cylinder 12, It is attached to the slide cylinder 12 by tightening a nut 74 on the tip of the screw 70 . In a state in which the linear piece 12A is attached to the sliding cylinder 12, the piece member 72 protrudes from the outer surface of the sliding cylinder 12, and the nut 74 protrudes from the inner surface of the sliding cylinder. The piece member 72 is inserted into the longitudinal groove 14B of the outer cylinder 14, and the nut 74 is inserted into the auxiliary cam groove 8C of the second rotary cylinder 8. As shown in FIG. The nut 74 has a circular shape, the diameter of the nut 74 is slightly smaller than the width of the auxiliary cam groove 8C, and a gap is provided between the nut 74 and the side surface of the auxiliary cam groove 8C. The nut 74 of the rectilinear member 12A is preferably made of a material harder than the roller 64 of the cam follower 12B, such as metal such as brass or stainless steel. The gap between the nut 74 and the auxiliary cam 8C is smaller than the thickness of the roller 64 in the radial direction.

These linear pieces 12A and cam followers 12B are provided on the sliding cylinder 12 at equal intervals in the circumferential direction. When the cam follower 12B moves along the cam groove 8A of the slide cylinder 12, the nut 74 moves within the auxiliary cam groove 8C. In this embodiment, the cam groove 8A and the auxiliary cam groove 8C have the same shape. In other words, the auxiliary cam groove 8C corresponds to the cam groove 8A so that the nut 74 can move in the auxiliary cam groove 8C when the cam follower 12B moves along the cam groove 8A. Any shape is acceptable.

With such a configuration, when the second rotating barrel 8 rotates in conjunction with the first rotating barrel 10, the second rotating barrel 8 moves in the optical axis direction together with the outer barrel 14, and furthermore, the sliding barrel 12 moves toward the second rotating barrel. It advances and retreats with respect to the rotating barrel 8 in the optical axis direction.

As shown in FIGS. 1 and 2, the first lens group A is surrounded and held by a first lens frame 30 . The first lens frame 30 is attached inside the tip of the sliding barrel 12 . As described above, when the first rotating barrel 10 is rotated with respect to the inner fixed barrel 6, the second rotating barrel 8 advances and retreats in the optical axis direction, and the sliding barrel 12 advances and retreats with respect to the second rotating barrel 8. do.

The second lens group B is surrounded and held by a second lens frame 32 . A top 32A is erected on the outer peripheral surface of the second lens frame 32. As shown in FIG. The piece 32A is inserted into the vertical groove 10a formed in the first rotary barrel 10 and the cam groove 6c of the inner fixed barrel 6. As shown in FIG. Accordingly, when the first rotating barrel 10 advances and retreats with respect to the inner fixed barrel 6 while rotating, the second lens frame 32 rotates in conjunction with the first rotating barrel 10 and rotates relative to the first rotating barrel 10 . Advance and retreat.

The third lens group C is surrounded and held by a third lens frame 34 . A top 34A is erected on the outer peripheral surface of the third lens frame 34. As shown in FIG. The piece 34A is inserted into the cam groove 10b formed in the first rotary barrel 10. As shown in FIG. Further, the rotation of the third lens group C is restrained by a guide member (not shown) extending from the fourth lens group D. As shown in FIG. As a result, the third lens frame 34 advances and retreats with respect to the first rotary barrel 10 without rotating when the first rotary barrel 10 advances and retreats with respect to the inner fixed barrel 6 while rotating. .

The fourth lens group D is surrounded and held by a fourth lens frame 36 . A top 36A is erected on the outer peripheral surface of the fourth lens frame 36. As shown in FIG. The pieces 36A are inserted into the horizontal grooves 10c formed in the first rotating barrel 10 and the longitudinal grooves (not shown) formed in the inner surface of the inner fixed barrel 6. As shown in FIG. Accordingly, when the first rotary barrel 10 advances and retreats while rotating with respect to the inner fixed barrel 6, the fourth lens frame 36 advances and retreats together with the first rotary barrel 10 without rotating.

The fifth lens group is surrounded and held by a fifth lens frame 38 . A top 38A is erected on the outer peripheral surface of the fifth lens frame 38. As shown in FIG. The coma 38A enters the cam groove 10d formed in the first rotary barrel 10 and the vertical groove (not shown) formed in the fourth lens frame 36. As shown in FIG. Thereby, the fifth lens frame 38 is configured to move forward and backward with respect to the first rotary barrel 10 without rotating when the first rotary barrel 10 is rotated with respect to the inner fixed barrel 6 .

The zoom lens barrel 1 also includes an aperture mechanism 40 arranged between the second lens group B and the third lens group C. As shown in FIG.

A zooming operation in the zoom lens barrel of this embodiment will be described below.
A zoom lens barrel 1 is used by attaching a mount 2 to a camera body. By attaching the mount 2 to the camera body, the outer fixed barrel 4 and the inner fixed barrel 6 are fixed to the camera body. A zoom operation can be performed by rotating the zoom operation ring 22 . When the zoom operation ring 22 is rotated, the first rotary barrel 10 and the second rotary barrel 8 are rotated accordingly.

When the first rotary barrel 10 is rotated with respect to the inner fixed barrel 6, the first rotary barrel 10 moves in the optical axis direction. Further, when the first rotary barrel 10 is rotated with respect to the inner fixed barrel 6, the second, third, fourth and fifth lens frames 32, 34, 36 and 38 respectively move in the optical axis direction.

Further, when the second rotating barrel 8 rotates, the second rotating barrel 8 moves along the optical axis together with the outer barrel 14, and the sliding barrel 12 advances and retreats with respect to the second rotating barrel 8 along the optical axis. This causes the first lens frame 30 to move in the optical axis direction.
Thereby, each lens group moves in the optical axis direction, and zooming is performed.

Here, when the zoom lens barrel 1 attached to the camera is dropped and the sliding barrel 12 collides with the ground, an impact is applied to the sliding barrel 12 . When an impact is applied to the slide cylinder 12, the roller 64 of the cam follower 12B first contacts the cam groove 8A of the second rotary cylinder 8, so that the roller 64 is sandwiched between the side surface of the cam groove 8A and the cam follower shaft 62. part is compressed. When a portion of the roller 64 is compressed in this manner, the side portion of the nut 74 of the linear movement piece 12A comes into contact with the side surface of the auxiliary cam groove 8C. Therefore, the roller 64 is not compressed and deformed any more, and it is possible to prevent excessive force from acting on the cam follower 12B and the cam groove 8A. This can prevent damage to the cam follower 12B and the cam groove 8A.

As described above, according to this embodiment, the following effects are achieved.
According to this embodiment, even if the slide cylinder 12 is subjected to an impact, the nut 74 of the rectilinear piece 12A collides with the edge of the auxiliary cam groove 8C, and the impact when the cam follower 12B collides with the cam groove 8A can be eliminated. As a result, damage to the cam follower 12B or the cam groove 8A can be prevented, and a smooth zooming operation can be maintained. Further, since the nut 74 of the rectilinear movement piece 12A is used, there is no need to provide a new member, and an increase in the number of members can be prevented.

Further, in this embodiment, the auxiliary cam groove 8C has a shape having the same trajectory as the cam groove 8A. As a result, smooth zooming can be maintained, and a space for forming the auxiliary cam groove 8C can be easily secured.

Further, in this embodiment, the cam follower 12B has a roller 64 made of an elastic material, the roller 64 is inserted into the cam groove 8A, and the diameter of the roller 64 is substantially equal to the width of the cam groove 8A. According to this embodiment, the roller 64 of the cam follower 12B is elastically deformed even when the slide cylinder 12 receives an impact. This can more reliably prevent damage to the cam follower 12B or the cam groove 8A.

Further, in this embodiment, the nut 74 of the rectilinear piece 12A enters into the auxiliary cam groove 8C with a gap formed between it and the side surface of the auxiliary cam groove 8C. According to this embodiment, during zooming, the slide cylinder 12 is guided by the cam follower 12B and the cam groove 8A, so smooth zooming can be maintained. When an impact is applied to the slide cylinder 12 and the roller 64 of the cam follower 12B is elastically deformed, it comes into contact with the side of the auxiliary cam groove 8C of the rectilinear piece 12A, thereby preventing damage to the cam follower 12B or the cam groove 8A.

Further, in the present embodiment, the material of the nut 74 of the rectilinear piece 12A is harder than the material of the roller 64. As shown in FIG. As a result, when the rectilinear moving piece 12A comes into contact with the side portion of the auxiliary cam groove 8C when an impact is applied, the impact acting on the roller 64 is extremely small, so that the roller 64 can be prevented from being damaged.

In the present embodiment, the outer cylinder 14 having the vertical groove 14B is disposed radially outside the sliding cylinder 12, and the cam groove 8A and the auxiliary cam groove 8C are formed radially inside the sliding cylinder 12. The case where the second rotary cylinder 8 is arranged has been described, but the present invention is not limited to this. The present invention can be applied even when the longitudinally grooved tube is arranged radially inside the sliding tube.

In addition, in the present embodiment, the case where the top member 72 of the rectilinear top (second top member) 12A has entered the longitudinal groove 14B of the outer cylinder 14 has been described, but this is not the only option, and the second top member , may be fitted in the cam groove.

Further, in the present embodiment, the case where the cylinder member is the outer cylinder 14 that does not rotate has been described, but the cylinder member may be a member that rotates. In this case, the present invention can be applied if the rotating barrel (second rotating barrel 8) and the barrel member are rotated at different rotation angles so that the barrel member and the rotating barrel are rotated relative to each other.

Further, in the present embodiment, the shape of the auxiliary cam groove 8C has been described as having the same trajectory as that of the cam groove 8A, but the present invention is not limited to this. For example, the inclination of the auxiliary cam groove 8C on the object side may be gentler than that of the cam groove 8A. According to such a configuration, it is possible to more efficiently absorb the impact when dropped.

1 zoom lens barrel 2 mount 4 outer fixed barrel 4A rear outer fixed barrel 4B front outer fixed barrel 6 inner fixed barrel 6A front cylindrical portion 6B rear cylindrical portion 6a cam groove 6c cam groove 8 second rotating barrel 8A cam groove 8B lateral groove 8C Auxiliary cam groove 8D Cam follower 10 First rotary cylinder 10A Front cylindrical part 10B Intermediate cylindrical part 10C Rear cylindrical part 10a Vertical groove 10b Cam groove 10c Lateral groove 10d Cam groove 12 Sliding cylinder 12A Linear piece 12B Cam follower 12C Through hole 12D Through hole 14 Outside Tube 14A Straight frame 14B Vertical groove 14C Top 20 Focus operation ring 22 Zoom operation ring 30 First lens frame 32 Second lens frame 32A Top 34 Third lens frame 34A Top 36 Fourth lens frame 36A Top 38 Fifth lens frame 38A Top 40 Aperture mechanism 60 Screw 62 Cam follower shaft 62A Through hole 62B Tip part 64 Roller 70 Screw 72 Top member 72A Through hole 74 Nut A First lens group B Second lens group C Third lens group D Fourth lens group E Fifth lens group

Claims (5)

a sliding cylinder;
a rotating cylinder provided on one side in the radial direction of the sliding cylinder;
a cylindrical member provided on the other side in the radial direction of the sliding cylinder,
The slide cylinder has a first piece member projecting to one side in the radial direction and a second piece member projecting to the other side in the radial direction,
A cam groove into which the first piece member enters is formed in the rotary cylinder,
A vertical groove into which the second piece member enters is formed in the cylindrical member,
A zoom lens barrel in which the sliding barrel extends in the optical axis direction by rotating the rotating barrel with respect to the barrel member,
The slide cylinder has a projecting portion projecting to the other side in the radial direction of the second piece member,
The protruding portion is constituted by a part of a member constituting the second piece member,
An auxiliary cam groove is formed in the rotary cylinder in addition to the cam groove,
A zoom lens barrel, wherein the projecting portion of the second top member is inserted into the auxiliary cam groove. 2. The zoom lens barrel according to claim 1, wherein said auxiliary cam groove has a shape having the same trajectory as said cam groove. The first piece member has a roller made of an elastic material, and the roller is inserted into the cam groove,
3. The zoom lens barrel according to claim 1, wherein the diameter of said roller is substantially equal to the width of said cam groove. 4. The zoom lens barrel according to claim 3, wherein said protruding portion of said second piece member enters into said auxiliary cam groove with a gap formed between it and the side surface of said auxiliary cam groove. 5. The zoom lens barrel according to claim 3, wherein the material of said protrusion is harder than the material of said roller.

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