JP7371471B2 - lens barrel - Google Patents

Description

The present invention relates to a lens barrel.

Lens barrels need to be prevented from wobbling.

Japanese Unexamined Patent Publication No. 7-120651

The lens barrel of the first aspect includes a first barrel having a straight groove, and a second barrel that has an engaging member that engages with the straight groove and is movable in the optical axis direction with respect to the first barrel. The engagement member includes a first member held by the second cylinder, a second member movable with respect to the first member, and a combination of the first member and the second member. The structure includes an elastic member disposed between the two members, and a central shaft portion that passes through the centers of the first member and the second member and is inclined with respect to a radial direction centered on the optical axis.

The lens barrel of the second aspect includes a first barrel having a straight groove, a second barrel having a cam groove and rotatable around the optical axis, and a first engaging member that engages with the straight groove. and a second engaging member that engages with the cam groove, and a third cylinder that is movable in the optical axis direction with respect to the first cylinder, and the first engaging member is a first member held in the third cylinder; a second member movable with respect to the first member; a first elastic member disposed between the first member and the second member; The second engaging member includes a third member held by the third cylinder, a fourth member movable with respect to the third member, and the third member and the fourth member. and a third elastic member disposed between the two elastic members.

FIG. 2 is a partial cross-sectional view of the lens barrel 1 of the first embodiment. FIG. 2 is a partial cross-sectional view of the lens barrel 1 in a direction perpendicular to the optical axis OA. 5 is a partial perspective view of a lens chamber 4 and an engaging member 5. FIG. 3 is a partial cross-sectional view of a lens chamber 4, a fixed tube 3, and an engaging member 5. FIG. FIG. 3 is a partial cross-sectional view of a lens barrel 101 according to a second embodiment. 3 is a partial perspective view of a lens chamber 104, an engaging member 5, and a second engaging member 105. FIG. FIG. 7 is a diagram showing the state of engagement between the second engaging member 105 and the cam groove 106a when viewed from the outer peripheral side of the cam cylinder 106. 3 is a partial cross-sectional view of the lens chamber 4, the cam cylinder 106, and the second engaging member 105. FIG. It is a sectional view of the 1st engagement member which engages with the straight groove in a 3rd embodiment. It is a sectional view of the 2nd engagement member which engages with the cam groove in a 3rd embodiment.

(First embodiment)
The first embodiment will be described below with reference to the drawings and the like. FIG. 1 is a partial sectional view of a lens barrel 1 according to the first embodiment. In the figure, only the outlines of other parts are shown with dotted lines. FIG. 2 is a partial cross-sectional view of the lens barrel 1 in a direction perpendicular to the optical axis OA (a partial cross-sectional view seen from the optical axis OA direction). FIG. 3 is a partial perspective view of the lens chamber 4 and an engaging member 5, which will be described later. FIG. 4 is a partial cross-sectional view of the lens chamber 4, the fixed cylinder 3, and the engaging member 5, which will be described later.

The lens barrel 1 is attachable to and detachable from the camera body 2. Note that in this embodiment, a lens barrel 1 that is detachable from a camera body 2 will be described, but the present invention is not limited to this, and may be applied to a camera in which the lens barrel 1 and camera body 2 are integrated. You can also do it.

The lens barrel 1 includes a fixed barrel 3 (first barrel) provided with a straight groove 31, and a lens chamber 4 (second barrel) arranged on the inner peripheral side of the fixed barrel 3. For example, the lens chamber 4 is linearly driven by a motor 7 provided on the fixed barrel 3, and is movable in the optical axis OA direction with respect to the fixed barrel 3. Note that the fixed barrel 3 described in the embodiment may be a movable barrel that is movable in the optical axis OA direction.

(Lens chamber 4)
The lens chamber 4 includes a lens frame 41 that holds the lens L on the inner circumference side, and a cylindrical tube part 42 that covers the outer circumference of the lens frame 41. As shown in FIG. 2, mounting recesses 43 are provided on the outer circumferential surface of the cylindrical portion 42 at three equal locations in the circumferential direction. As shown in FIG. 3, two mounting recesses 43 are provided at two of the three locations P2 and P3, which are lined up along the optical axis OA direction. One mounting recess 43 is provided at one of the three locations P1.

(Mounting recess 43)
The internal shape of the mounting recess 43 is triangular in cross section in the direction orthogonal to the optical axis OA, as shown in FIG. That is, in a cross section perpendicular to the optical axis OA, the mounting recess 43 has two side surfaces that are inclined at approximately 45 degrees with respect to the straight line B extending in the radial direction from the optical axis OA. The angle between the first side surface 43f, which is one side surface, and the second side surface 43g, which is the other side surface, is about 90 degrees.

(Fixed tube 3)
The fixed barrel 3 disposed on the outer circumferential side of the lens chamber 4 is provided with rectilinear grooves 31 extending along the optical axis OA direction at three equal circumferential locations. The straight groove 31 has a constant width, extends along the optical axis OA direction, and has two side surfaces facing each other. The first side surface 31f, which is one side surface, and the second side surface 31g, which is the other side surface, are substantially parallel to each other. Further, the first side surface 31f and the second side surface 31g are substantially parallel to the straight line C connecting the center of the width of the rectilinear groove 31 and the optical axis OA.

(Engagement member 5)
An engaging member 5 that is inserted into the straight groove 31 of the fixed barrel 3 is attached to the lens chamber 4 . The engagement member 5 is fixed inside a mounting recess 43 provided on the outer peripheral surface of the lens chamber 4 . That is, since there are two mounting recesses 43 at two of the three circumferentially equal locations P1, P2, and P3, two of the mounting recesses 43 are attached to the two engaging members 5, as shown in FIG. They are attached in line along the optical axis OA direction. Since there is only one attachment recess 43 at one of the three locations P1, one engagement member 5 is attached.

In this way, by using only one engaging member 5 at one of the three locations P1, excessive restraint of the fixed tube 3 of the lens chamber 4 can be prevented. One point P1 to which one engagement member 5 is attached is such that when the lens barrel 1 is attached to the camera body 2 and held in the correct position, the lens chamber 4 is not biased with respect to the fixed barrel 3 and is balanced. A good location is preferred. The normal position is a position where the long side of the substantially rectangular image sensor is parallel to the ground. In the embodiment, the normal position is shown in FIG. 2 with one location P1 on top, and the engagement member 5 is located at one location P1 on the upper side, one location P2 on the left side, and one location P3 on the right side. It is located. In this case, one engagement member 5 is attached to one spot P1 directly above, which has no bias and is well-balanced, and two engagement members 5 are attached to one spot P2 on the lower left side and one spot P3 on the lower right side. Member 5 is attached.

However, the present invention is not limited to this. For example, in the normal position, P1 to which one engagement member 5 is attached is placed directly below, and P2 and P3 to which two engagement members 5 are attached are placed on the upper left side and upper right side, respectively. may be done.
Furthermore, two engaging members 5 may be attached to each of three positions on the outer circumferential surface of the lens chamber 4 at equal intervals in the circumferential direction. In this case, the strength against impact can be increased. Furthermore, each number does not have to be two, and there may be a plurality of two or more, such as three.

The engaging member 5 has an outer circumferential engaging portion 51 (second member) disposed on the outer circumferential side, an inner circumferential engaging portion 52 (first member) disposed on the inner circumferential side, and an outer circumferential engaging portion 51 (second member) disposed on the inner circumferential side. A central shaft portion 53 extending through the center of the portion 51 and the inner engaging portion 52 is disposed between the outer engaging portion 51 and the inner engaging portion 52, and is arranged between the outer engaging portion 51 and the inner engaging portion 52. It includes an elastic member 54 that biases in a direction away from the circumferential engaging portion 52.

(Outer circumferential engagement portion 51)
The outer circumferential engaging portion 51 is a rotating body centered on the axis A, and includes a truncated cone portion 51a and a disk portion 51b that has the same diameter as the bottom surface of the truncated cone portion 51a and is continuous from the bottom surface. , a through hole 51c is provided in the center. Further, an annular groove 51e extending in the direction of the axis A is provided from the bottom surface of the disc portion 51b toward the truncated cone portion 51a.

As shown in FIG. 4, when the truncated cone portion 51a of the outer peripheral side engaging portion 51 is cut along a plane passing through the axis A, two sides 51f and 51g formed by the contour of the side surface of the truncated cone portion 51a are: They extend in directions substantially perpendicular to each other, and the intersection point of the extensions lies on the axis A. That is, the apex angle θ1 of the isosceles triangle formed by the two sides 51f and 51g and the lower side of the truncated cone portion 51a is approximately 90 degrees, and the inclination of the two sides 51f and 51g is as follows. Each is approximately 45° to axis A.

(Inner circumferential engagement portion 52)
The inner circumferential engaging portion 52 is a rotating body centered on the axis A, and has a truncated cone portion 52a and a disk portion 52b that has the same diameter as the bottom surface of the truncated cone portion 52a and is continuous from the bottom surface. However, a through hole 52c is provided in the center.
The outer engaging portion 51 and the inner engaging portion 52 have the same shape except that the outer engaging portion 51 is provided with an annular groove 51e. The circumferential engaging portion 52 is arranged such that the disk portions 51b and 52b are opposed to each other. Alternatively, an annular groove may be provided in the inner circumferential engaging portion 52 so that the inner circumferential engaging portion 52 has the same shape.

When the truncated conical portion 52a of the inner circumferential engagement portion 52 is cut along a plane passing through the axis A, two sides 52f and 52g formed by the contour of the side surface of the truncated conical portion 52a are in directions substantially orthogonal to each other. The intersection point of the extension is on the axis A. That is, the apex angle θ2 of the isosceles triangle formed by the two sides 52f and 52g and the lower side of the truncated cone portion 52a is approximately 90 degrees, and the inclination of the two sides 52f and 52g is as follows. It is approximately 45° to axis A.

Therefore, the side 52f of the inner circumferential engaging portion 52 and the side 51g of the outer circumferential engaging portion 51 located on the opposite side with the central shaft portion 53 in between are substantially parallel to each other. Further, the side 52g of the inner circumferential engaging portion 52 and the side 51f of the outer circumferential engaging portion 51 on the opposite side with the central shaft portion 53 in between are parallel to each other.

(Central shaft portion 53)
The central shaft portion 53 includes an outer shaft portion 55 that passes through the through hole 51c of the outer engaging portion 51, an inner shaft portion 56 that passes through the through hole 52c of the inner engaging portion 52, and an outer shaft portion 56 that passes through the through hole 52c of the inner engaging portion 52. A retaining portion 57 attached to the outer circumferential end of the shaft portion 55 is provided.

(Inner shaft portion 56)
The inner shaft portion 56 includes a threaded portion 56a at the inner end, a flange 56b provided on the outer periphery of the threaded portion 56a and having a wider diameter than the threaded portion 56a, and an insertion portion extending from the flange 56b toward the outer periphery. A portion 56c is provided. A screw hole 56d is provided at the center of the insertion portion 56c.

(Outer shaft portion 55)
The outer shaft portion 55 has a threaded portion 55a at its inner tip, a flange 55b provided on the outer periphery of the threaded portion 55a and having a wider diameter than the threaded portion 55a, and an insertion portion extending from the flange 55b toward the outer periphery. A portion 55c is provided. A screw hole 55d is provided at the center of the insertion portion 55c.
Further, the outer peripheral shaft portion 55 is provided with a step on the outer peripheral edge of the outer peripheral surface of the flange portion 55b so that the thickness becomes thinner in a circular ring shape centered on the axis A, and the outer side of the step is a spring. It serves as a cradle 55e. The size of the spring holder 55e is approximately equal to the size of the annular groove 51e provided in the outer circumferential engaging portion 51.

(Keeping part 57)
The retaining portion 57 includes a screw portion 57a and a lid portion 57b. The threaded portion 57a is screwed into the screw hole 55d of the outer shaft portion 55, and the lid portion 57b is in contact with the upper end of the insertion portion 55c of the outer shaft portion 55, and the cover portion 57b is in contact with the upper end of the insertion portion 55c of the outer shaft portion 55, and the circumference around the axis A is smaller than the insertion portion 55c. protrudes in the direction. This protruding portion prevents the outer circumferential engaging portion 51 from coming off from the central shaft portion 53.

(Elastic member 54)
The elastic member 54 is a coil spring, and is placed on a spring holder 55e of the outer shaft portion 55 and inserted into the annular groove 51e of the outer engaging portion 51.

The inner circumferential engaging portion 52 is inserted into the insertion portion 56c of the inner circumferential shaft portion 56 with the truncated conical portion 52a side facing downward. The threaded portion 55a of the outer shaft portion 55 is screwed into the screw hole 56d of the inner shaft portion 56, and the lower surface of the collar portion 55b is in contact with the upper surface of the insertion portion 56c of the inner shaft portion 56. . An elastic member 54 is arranged on a spring holder 55e of the outer peripheral shaft portion 55.
The outer circumferential engaging portion 51 is inserted into the insertion portion 55c of the outer circumferential shaft portion 55 with the disk portion 51b side facing down, and the elastic member 54 is inserted into the annular groove 51e. The threaded portion 57a of the retaining portion 57 is screwed into the threaded hole 55d of the outer shaft portion 55.

The length of the outer circumferential engaging portion 51 in the direction of the axis A is shorter than the insertion portion 55c of the central shaft portion 53 that passes through the through hole 51c of the outer circumferential engaging portion 51. Therefore, the outer circumferential engaging portion 51 is movable up and down in the direction of the axis A within the length range of the insertion portion 55c.
The elastic member 54 protrudes from the lower bottom surface of the outer circumferential engaging portion 51 toward the spring holder 55e and comes into contact with the spring holder 55e. As a result, the outer engagement portion 51 is biased in a direction away from the inner engagement portion 52 while being movable at least in the direction of the axis A with respect to the central shaft portion 53 by the elastic member 54. is maintained. Note that, although it is preferable that the outer circumferential engaging portion 51 rotates with respect to the central shaft portion 53, it does not necessarily need to rotate. In that case, it is preferable that the coefficient of friction between the second side surface 31g of the straight groove 31 and the side surface of the truncated cone portion 51a is small.

On the other hand, the inner circumferential engaging portion 52 does not move in the direction of the axis A with respect to the central shaft portion 53. Note that, although it is preferable that the inner circumferential engaging portion 52 also rotates with respect to the central shaft portion 53, it does not necessarily need to rotate. In that case, it is preferable that the coefficient of friction between the first side surface 31f of the straight groove 31 and the side surface of the truncated conical portion 52a is small.

The engaging member 5 is attached to the lens chamber 4 as follows.
The threaded portion of the central shaft portion 53 is approximately perpendicular to the first side surface 43f of the two side surfaces 43f and 43g provided inside the mounting recess 43 of the lens chamber 4. 56a is inserted. At this time, as shown in FIG. 4, the central axis portion 53 is inclined at approximately 45 degrees with respect to a straight line C extending in the radial direction centered on the optical axis OA in a cross section in a direction perpendicular to the optical axis OA. .

The inclination of the side edge 51g of the truncated cone portion 51a of the outer circumferential engaging portion 51 is approximately 45° with respect to the central shaft portion 53 (axis A) as described above. The inclination of the side edge 52f of the truncated cone portion 52a of the inner circumferential engaging portion 52 is approximately 45° with respect to the central shaft portion 53 (axis A) as described above.
Therefore, in the cross section shown in FIG. 4, the side 52f of the inner circumferential engaging portion 52 is approximately parallel to one first side 31f of the straight groove 31. The side 51g of the outer circumferential engaging portion 51 is substantially parallel to the other second side 31g of the straight groove 31.

As shown in FIG. 4, the inner peripheral engaging portion 52 has a side 52f of the truncated conical portion 52a protruding outward from the mounting recess 43, and a side 52g of the truncated cone 52a located inside the mounting recess 43. There is. The outer circumferential engaging portion 51 protrudes to the outer circumferential side of the mounting recess 43 .
A portion of the engaging member 5 that protrudes toward the outer circumference is inserted into a straight groove 31 provided in the fixed cylinder 3.
At this time, the side 52f of the inner circumferential side engaging part 52 comes into contact (line contact) with the first side 31f of the straight groove 31, and the side 51g of the outer circumferential side engaging part 51 comes into contact with the first side 31f of the straight groove 31. It makes contact (line contact) with the second side surface 31g.

The biasing direction of the elastic member 54 is approximately parallel to the inclination of the central shaft portion 53, and is inclined at approximately 45° with respect to the radial direction centered on the optical axis OA. In this state, when the outer circumferential side engaging part 51 is pressed against the inner circumferential side engaging part 52 by the elastic member 54, the outer circumferential side engaging part 51 moves in a direction away from the inner circumferential side engaging part 52. . As a result, the side surface (51 g of the side surface) of the outer circumferential engaging portion 51 is pressed against the second side surface 31 g of the straight groove 31 . Then, the second side surface 31g of the straight groove 31 is pushed in the circumferential direction, and the side surface (side 52f) of the inner circumferential engaging portion 52 is also pressed against the first side surface 31f of the straight groove 31. In this way, the side 52f comes into contact (line contact) with the first side 31f, and the side 51g comes into contact (line contact) with the second side 31g.

As a result, even if the groove width of the straight groove 31 changes due to manufacturing errors, the engaging member 5 is always in contact with the first side surface 31f and the second side surface 31g of the straight groove 31, and the fixed cylinder 3 It is possible to eliminate looseness between the lens chamber 4 and the lens chamber 4.
Note that if the biasing force of the elastic member 54 is strong enough, the difference in posture of the lens L held in the lens chamber 4 with respect to the fixed barrel 3, that is, when the lens barrel is oriented in various directions such as vertically or horizontally, , it is possible to reduce differences in accuracy caused by differences in posture.

For example, if a bearing is used instead of the engagement member 5, a gap will be created between the bearing and the straight groove 31, and play will be created between the fixed barrel 3 and the lens chamber 4. However, in this embodiment, the inner circumferential side engaging part 52 and the outer circumferential side engaging part 51 are urged in a direction away from each other by the elastic member 54, and the inner circumferential side engaging part 52 is forced to move away from the first side surface of the straight groove 31. 31f, and the outer circumferential engaging portion 51 abuts against the second side surface 31g of the straight groove 31. Therefore, no gap is generated between the engaging member 5 and the straight groove 31, and play between the fixed barrel 3 and the lens chamber 4 can be reduced.

(Second embodiment)
Next, a second embodiment will be described with reference to the drawings and the like. FIG. 5 is a partial cross-sectional view of the lens barrel 101 of the second embodiment. As in the first embodiment, only the outlines of parts other than the main parts are shown with dotted lines in the figures. Hereinafter, the same parts as in the first embodiment will be denoted by the same reference numerals, and the explanation will be omitted. Furthermore, although the engaging member 5 is the same as that in the first embodiment, it is referred to as a first engaging member 5 in the second embodiment to make the explanation easier to understand.
FIG. 6 is a partial perspective view of the lens chamber 104, the first engaging member 5, and the second engaging member 105. FIG. 7 is a diagram showing the state of engagement between the second engaging member 105 and the cam groove 106a when viewed from the outer peripheral side of the cam cylinder 106. FIG. 8 is a partial sectional view of the lens chamber 104, the cam cylinder 106, and the second engaging member 105.

The lens barrel 101 of the second embodiment differs from the lens barrel 1 of the first embodiment in the following points.
A cam cylinder 106 (second cylinder) provided with a cam groove 106a is arranged on the outer peripheral side of the fixed cylinder 3 (first cylinder) having a straight groove 31. Not only the first engaging member 5 that engages with the linear groove 31 but also the second engaging member 105 that engages with the cam groove 106a are attached to the outer periphery of the lens chamber 104 (third cylinder). When the cam barrel 106 is rotated by the rotation of the zoom ring or motor, the lens chamber 104 is moved straight along the straight groove 31 in the direction of the optical axis OA, and is driven along the cam groove 106a in the direction of the optical axis OA. point to be made.

(Lens chamber 104)
Similar to the first embodiment, two first engaging members 5 are attached to two locations on the outer peripheral surface of the cylindrical portion 142 of the lens chamber 104 along the optical axis direction. A protrusion 145 protruding toward the outer circumference is provided between the two first engaging members 5 on one of them. The protrusion 145 has a side surface 145a inclined at about 45 degrees with respect to the optical axis OA in a cross section extending in the optical axis OA direction through the optical axis OA shown in FIG. The second engaging member 105 is held on a side surface 145a of the lens chamber 104 and inserted into a cam groove 106a provided in the cam cylinder 106.

(Cam tube 106)
The cam cylinder 106 is provided with a cam groove 106a. The cam groove 106a has a constant width, and two opposing side surfaces 106f and 106g are substantially parallel to each other.

(Second engagement member 105)
The first engaging member 5 and the second engaging member 105 have different shapes in the outer circumferential engaging portion and the inner circumferential engaging portion. Further, description of the similar configurations between the first engaging member 5 and the second engaging member 105 will be omitted.
In the second engagement member 105, an outer engagement portion 151 (fourth member) includes a hemispherical portion 151a and a disc portion 151b, and an inner engagement portion 152 (third member) includes a hemispherical portion 152a and a circular plate portion 151b. The difference is that it includes a plate portion 152b.
The central shaft portion 53 of the second engaging member 105 is attached so as to be substantially orthogonal to the side surface 145a of the protrusion 145 of the lens chamber 4. As a result, the central axis portion 53 is inclined at approximately 45° with respect to the radial direction centered on the optical axis OA in a cross section taken in a direction perpendicular to the optical axis OA, as shown in FIG.

The biasing direction of the elastic member 154 is approximately parallel to the direction of inclination of the central shaft portion 53, and is inclined at 45 degrees with respect to the radial direction centered on the optical axis OA. Therefore, the outer circumferential engaging part 151 is moved to the inner circumferential engaging part 152 by the urging force of the elastic member 154 (third elastic member) disposed between the outer circumferential engaging part 151 and the inner circumferential engaging part 152. When it is pushed and moved in the direction away from the cam groove 106a, the side surface of the outer circumferential engaging portion 151 is pressed against the second side surface 106g of the cam groove 106a. Then, the second side surface 106g of the cam groove 106a is pushed in the direction of the optical axis OA, and the first side surface 106f of the cam groove 106a comes into contact with the side surface of the inner circumferential engaging portion 152.
At this time, since the hemispherical portion 151a of the outer circumferential engaging portion 151 has a hemispherical shape, the outer circumferential engaging portion 151 and the second side surface 106g of the cam groove 106a come into point contact.
Further, since the hemispherical portion 152a of the inner circumferential engaging portion 152 is also hemispherical, the inner circumferential engaging portion 152 and the first side surface 106f of the cam groove 106a abut point contact.

Note that, similarly to the first embodiment, the first engaging member 5 includes an inner circumferential engaging portion 52 held in the lens chamber 104 and an outer circumferential engaging portion movable with respect to the inner circumferential engaging portion 52. It has a mating portion 51 and an elastic member 54 (first elastic member) disposed between the outer circumferential engaging portion 51 and the inner circumferential engaging portion 52.
Similarly to the first embodiment, the side surface of the inner engagement portion 52 of the first engagement member 5 is in line contact with the first side surface 31f of the straight groove 31, and the side surface of the outer engagement portion 51 is in line contact with the first side surface 31f of the straight groove 31. is in line contact with the second side surface 31g of the straight groove 31.

As described above, according to the second embodiment, even if the groove width of the cam groove 106a changes due to manufacturing errors or the like, the second engaging member 105 is always in contact with the side surfaces 106f and 106g of the cam groove 106a, and the cam Play between the tube 106 and the lens chamber 104 can be removed.
Note that if the biasing force of the elastic member 54 is strong enough, the difference in posture of the lens L held in the lens chamber 104 with respect to the fixed barrel 3, that is, when the lens barrel is oriented in various directions, such as vertically or horizontally, , accuracy differences caused by differences in posture can also be reduced.

In the case of the cam groove 106a, unlike the straight groove 31, the inclination angle of the cam groove 106a is not constant. However, since the second engaging member 105 has hemispherical portions 151a and 152a, even if the inclination angle of the cam groove 106a changes, the second engaging member 105 comes into contact with the side surfaces 106f and 106g of the cam groove 106a. becomes possible.

Note that, similarly to the first embodiment, even if the groove width of the straight groove 31 changes, the engagement member 5 is always in contact with the side surface of the straight groove 31, and the relationship between the fixed barrel 3 and the lens chamber 4 is maintained. You can remove the gap in between.

For example, if a bearing is used instead of the engaging member 105, a gap will be created between the bearing and the cam groove 106a, and play will occur between the cam barrel 106 and the lens chamber 104. However, in this embodiment, the inner circumferential side engaging part 152 and the outer circumferential side engaging part 151 are urged in a direction away from each other by the elastic member 154, and the inner circumferential side engaging part 152 is forced to move away from the first side surface of the cam groove 106a. 106f, and the outer circumferential engaging portion 151 abuts against the second side surface 106g of the cam groove 106a. Therefore, no gap is created between the engaging member 105 and the cam groove 106a, and play between the cam barrel 106 and the lens chamber 104 can be reduced.

(Third embodiment)
Next, a third embodiment will be described with reference to the drawings and the like. The third embodiment differs from the first and second embodiments in the structure of the engaging member. Note that description of parts similar to those in the first embodiment and the second embodiment will be omitted.

(First engaging member 205)
FIG. 9 is a sectional view of the first engagement member 205 of the third embodiment that engages with the straight groove 31. The central shaft portion 253 of the first engagement member 205 includes an outer peripheral shaft portion 255 and an inner peripheral shaft portion 256. The inner peripheral shaft portion 256 is substantially the same as that in the first and second embodiments, so a description thereof will be omitted.
The outer peripheral shaft portion 255 includes a cylindrical insertion portion 255c, screw portions 255a1 and 255a2 provided at both ends of the insertion portion 255c, and a collar portion 255b provided at the center of the insertion portion 255c. An outer engaging portion 251 is disposed on the outer circumferential side of the insertion portion 255c with a bearing 251h interposed therebetween. An inner engagement portion 252 is disposed in a portion of the insertion portion 255c on the inner circumference side of the flange portion 255b, with a bearing 252h interposed therebetween. Further, a plate spring is disposed as the elastic member 254 between the flange portion 255d and the outer circumferential engaging portion 251. The elastic member 254 presses the outer circumferential engaging portion 251 toward the outer circumferential side relative to the inner circumferential engaging portion 252 .

(Second engagement member 305)
FIG. 10 is a sectional view of the second engagement member 305 of the third embodiment that engages with the cam groove 106a. The central shaft portion 353 of the second engagement member 305 includes an outer peripheral shaft portion 355 and an inner peripheral shaft portion 356. The inner circumferential shaft portion 356 is substantially the same as in the first and second embodiments, so a description thereof will be omitted.
Further, similarly to the first engaging member 205, the outer circumferential side shaft portion 355 has a cylindrical insertion portion 355c and threaded portions 355a1 and 355a2 provided at both ends of the insertion portion 355c. A flange portion 355b is provided at the center of the portion 355c. An outer engagement portion 351 is disposed on the outer circumference side of the insertion portion 355c with a bearing 351h interposed therebetween. An inner engagement portion 352 is disposed in a portion of the insertion portion 355c on the inner circumference side of the flange portion 355b, with a bearing 352h interposed therebetween. Further, a plate spring is disposed as the elastic member 354 between the flange portion 355d and the outer circumferential engaging portion 351. The elastic member 254 presses the outer engagement portion 251 toward the outer circumference relative to the inner engagement portion 352 .

The lens barrel using the first engaging member 205 and the second engaging member 305 of the third embodiment also has a space between the fixed barrel 3 and the lens chamber 4, similarly to the first embodiment and the second embodiment. The play between the cam barrel 106 and the lens chamber 104 can be removed.

Furthermore, according to the third embodiment, since the bearings 251h and 252h are disposed between the central shaft portion 253, the outer peripheral engaging portion 251, and the inner peripheral engaging portion 252, The outer engagement portion 251 and the inner engagement portion 252 rotate smoothly. Therefore, the first engaging member 205 moves more smoothly within the straight groove 31.

Similarly, since bearings 351h and 352h are disposed between the central shaft portion 353, the outer peripheral engaging portion 351, and the inner peripheral engaging portion 352, the outer peripheral engaging portion 351 and the inner circumferential engaging portion 352 rotate smoothly. Therefore, the second engaging member 305 moves more smoothly within the cam groove 106a.

Although preferred embodiments have been described above, the present invention is not limited to this, and any combination is possible.

1: Lens barrel, 3: Fixed barrel (first barrel), 31: Straight groove, 31f: First side surface, 31g: Second side surface, 4: Lens chamber (second barrel), 41: Lens frame, 42: Cylindrical portion, 43: Mounting recess, 43f: Side surface (first side surface), 43g: Side surface (second side surface), 5: Engagement member, first engagement member, 51: Outer circumference side engagement portion (second member) , 51: second member, 51a: truncated cone portion, 51b: disc portion, 51c: through hole, 51e: annular groove, 51f: side side, 51g: side side, 52: inner peripheral side engaging portion (first 1 member), 52a: truncated conical part, 52b: disk part, 52c: through hole, 52f: side side, 52g: side side, 53: central shaft part, 54: elastic member, 55: outer peripheral side shaft part, 55a : threaded part, 55b: collar part, 55c: insertion part, 55d: screw hole, 55e: spring holder, 56: inner peripheral shaft part, 56a: threaded part, 56b: collar part, 56c: insertion part, 56d: Screw hole, 57: Retaining part, 57a: Threaded part, 57b: Lid, 7: Motor, 101: Lens barrel, 104: Lens chamber, 105: Second engaging member (second cylinder), 106: Cam Cylinder, 106a: Cam groove, 106f: Side surface (first side surface), 106g: Side surface (second side surface), 142: Cylindrical portion, 145: Projection, 145a: Side surface, 151: Outer peripheral side engaging portion, 151a: Hemisphere part, 151g: side, 152: inner peripheral side engaging part, 152a: hemispherical part, 152f: side, 154: elastic member, 205: first engaging member, 251: outer peripheral side engaging part, 251h: bearing , 252: Inner circumference side engaging part, 252h: Bearing, 253: Center shaft part, 253d: Flange part, 254: Elastic member, 255: Outer circumference side shaft part, 255a1: Thread part, 255a2: Thread part, 255b: Flange part, 255c: insertion part, 256: inner circumference side shaft part, 305: second engagement member, 351: outer circumference side engagement part, 351h: bearing, 352: inner circumference side engagement part, 352h: bearing, 353: Central shaft part, 353d: Flange part, 354: Elastic member, 355: Outer shaft part, 355a1: Thread part, 355a2: Thread part, 355b: Flange part, 355c: Insertion part, 356: Inner shaft part

Claims (12)

a first cylinder having a straight groove;
a second cylinder that has an engaging member that engages with the straight groove and is movable in the optical axis direction with respect to the first cylinder,
The engagement member is
a first member held in the second cylinder;
a second member movable relative to the first member;
an elastic member disposed between the first member and the second member;
A lens barrel having a central shaft portion that passes through the centers of the first member and the second member and is inclined with respect to a radial direction centered on the optical axis. the first member contacts one side surface of the straight groove;
The lens barrel according to claim 1, wherein the second member abuts the other side surface of the straight groove. The lens barrel according to claim 2, wherein the first member is in line contact with the one side surface of the straight groove. The lens barrel according to claim 2 or 3, wherein the second member is in line contact with the other side surface of the straight groove. 5. The lens barrel according to claim 1, wherein the biasing direction of the elastic member is inclined with respect to a radial direction centered on the optical axis. The lens barrel according to any one of claims 1 to 5, wherein the biasing direction of the elastic member and the axial direction of the central axis of the engaging member are substantially parallel. The lens barrel according to any one of claims 1 to 6, wherein a plurality of the engaging members are provided along the optical axis direction. The first cylinder has three straight grooves,
The lens barrel according to any one of claims 1 to 7, wherein two of the three straight grooves engage with at least two of the engaging members, respectively. The lens barrel according to any one of claims 1 to 8, further comprising a drive unit that moves the second barrel in the optical axis direction. The lens barrel according to any one of claims 1 to 9, wherein the elastic member generates an urging force in a direction in which the first member and the second member are separated. a first cylinder having a straight groove;
a second cylinder having a cam groove and rotatable around the optical axis;
a first engaging member that engages with the straight groove; and a second engaging member that engages with the cam groove;
a third cylinder movable in the optical axis direction with respect to the first cylinder,
The first engaging member is arranged between a first member held by the third cylinder, a second member movable with respect to the first member, and the first member and the second member. a first elastic member,
The second engaging member is arranged between a third member held by the third cylinder, a fourth member movable with respect to the third member, and the third member and the fourth member. and a third elastic member. the first member and the second member are in line contact with the straight groove;
the third member and the fourth member are in point contact with the cam groove;
The lens barrel according to claim 11.

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