JP6540991B2 - Cam mechanism and optical device - Google Patents

Description

  The present invention relates to a cam mechanism for driving an optical element and an optical apparatus provided with the cam mechanism.

  It is known that a grooved cam mechanism is used as a focusing mechanism or a zoom mechanism of a photographing lens. For example, a cam follower pin is provided on the outer periphery of a lens frame configured to be movable in the optical axis direction by a slide mechanism, and a cam ring having a cam groove engaged with the cam follower pin provided on the inner periphery is rotated about the optical axis. Thus, the lens attached to the lens frame can be driven in the optical axis direction.

  In a lens system using a grooved cam mechanism, it is necessary to provide a certain amount of play between the cam follower pin and the cam groove so that the lens can be driven smoothly, but the provision of the play causes a problem that the lens frame rattles. there were.

  In Patent Document 1, an elastic member having an outer diameter larger than the width of the cam groove is provided on the outer periphery of the sliding portion of the cam follower pin in contact with the cam groove, and the elastic member is pressed into the cam groove. A technique for suppressing rattling is described.

Unexamined-Japanese-Patent No. 2006-276219

  However, in the technique described in Patent Document 1, the sliding portion in contact with the cam groove is elastically deformed by press-fitting, so the contact area between the cam groove and the sliding portion is increased, and the sliding resistance (frictional resistance) is large. Problem of becoming

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cam mechanism which is free from rattling and has a small sliding resistance, and an optical apparatus provided with the cam mechanism. It is.

  An optical apparatus according to an embodiment of the present invention includes an optical element and a cam mechanism that drives the optical element in the optical axis direction, and the cam mechanism includes a first track surface and a side facing the first track surface. A second track surface provided on the second track surface and a cam follower in contact with the first track surface and the second track surface, the cam follower rolling on the first track surface, and the second track surface And a sliding portion for sliding the

  In the above optical device, the rolling portion has rubber elasticity, the cam follower is sandwiched between the first raceway surface and the second raceway surface, and the sliding portion is the second raceway by the elastic restoring force of the rolling portion. It is good also as composition pressed down to a field.

  In the above optical apparatus, the cam mechanism may include a wall portion in which the cam hole is formed, and the first raceway surface and the second raceway surface may be formed on the inner peripheral surface of the cam hole.

  In the above optical device, the cam hole has a narrow cam groove formed on one surface side of the wall portion, and a wide cam groove formed on the other surface side of the wall portion and wider than the narrow cam groove. A first raceway surface is formed on one of the narrow cam groove and the wide cam groove, and a second raceway surface is formed on the other of the narrow cam groove and the wide cam groove, and central races of the narrow cam groove and the wide cam groove It may be configured to be shifted in the groove width direction.

  In the above-described optical device, a configuration including a first annular member to which a cam follower is attached, and a second annular member formed with a first raceway surface and a second raceway surface and arranged concentrically with the first annular member. It may be

  In the above-mentioned optical device, the first track surface and the second track surface are formed, and further comprising a third annular member disposed concentrically with the first annular member, and the rolling portion is the first track of the second annular member The first rolling portion rolling on the surface and the second rolling portion rolling on the first raceway surface of the third annular member, wherein the sliding portion is the second raceway of the second annular member It may be configured to include a first sliding portion sliding on the surface and a second sliding portion sliding on the second raceway surface of the third annular member.

  In the above-described optical device, the sliding portion may be integrally formed. In this case, the second annular member and the third annular member are disposed between the first sliding surface sliding with the second annular member and the second sliding surface sliding with the third annular member. It is good also as composition formed in the crevice which does not contact.

  A cam mechanism according to an embodiment of the present invention includes a first ring having a guide groove, a cam follower fitted with the guide groove, and a second ring to which the cam follower is fixed, and the guide groove includes An inner peripheral groove formed on the inner peripheral side of one ring, and an outer peripheral groove formed on the outer peripheral side of the first ring, offset in the groove width direction with respect to the inner peripheral groove; The cam follower includes a column, a roller rotatably supported by the column, and a slider fixed to the column, wherein the roller contacts a wall surface of one of the inner groove and the outer groove, and the slider Is in contact with the wall surface of the other groove of the inner circumferential groove and the outer groove, and the radius of the roller before the cam follower fits into the guide groove is the distance from the center locus of the other groove to the wall of one groove Greater than.

A cam mechanism according to an embodiment of the present invention includes a first ring having a first guide groove, a second ring having a second guide groove extending in a direction intersecting with the guide groove, a first guide groove, and a first guide groove. (2) A cam follower fitted to the guide groove and a moving frame to which the cam follower is fixed, and the first guide groove and the second guide groove are respectively formed on the inner circumferential side of the first ring and the second ring The cam follower has a support post, and an inner peripheral groove and an outer peripheral groove offset from the inner peripheral groove in the groove width direction on the outer peripheral side of the first ring and the second ring . A first roller rotatably supported by the column and in contact with the first guide groove, a second roller rotatably supported by the column and in contact with the second guide groove, and a slider fixed to the column The first roller is in contact with the wall surface of one groove of the inner circumferential groove and the outer circumferential groove of the first guide groove, (2) The roller contacts the wall surface of one of the inner and outer groove portions of the second guide groove, and the slider contacts the wall surface of the other groove of the inner and outer groove portions of the first guide groove, And the radius of the first roller in contact with the wall surface of the other groove of the inner circumferential groove and the outer circumferential groove of the second guiding groove and before the cam follower is fitted into the first guiding groove The radius of the second roller before the cam follower is fitted in the second guide groove is larger than the distance from the center locus of the other groove to the wall surface of one groove of the first guide groove, and the radius of the second roller is the other It is larger than the distance from the center track of the groove to the wall surface of one groove of the second guide groove.

  According to the embodiment of the present invention, a cam mechanism with no rattling and low sliding resistance is realized.

It is an exploded perspective view of an interchangeable lens concerning an embodiment of the present invention. It is a longitudinal cross-sectional view of the interchangeable lens which concerns on embodiment of this invention. It is a figure explaining the arrangement relation of a cam follower and two cam holes. It is the figure which expanded cam follower vicinity of FIG. It is a longitudinal cross-sectional view of the cam hole formed in the zoom cam ring. It is a longitudinal cross-sectional view of the cam hole formed in the zoom fixing ring. It is a longitudinal cross-sectional view of a screw formed on the third lens moving frame. It is a longitudinal cross-sectional view of a cam follower. It is sectional drawing which shows the connection structure of the zoom cam ring, zoom fixed ring, and 3rd lens moving frame via a cam follower. It is sectional drawing which shows the connection structure of the zoom cam ring, zoom fixed ring, and 3rd lens moving frame via a cam follower. It is a longitudinal cross-sectional view explaining the grooved cam mechanism of the 1st modification of embodiment of this invention. It is a longitudinal cross-sectional view explaining the grooved cam mechanism of the 2nd modification of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of Entire Interchangeable Lens 1]
FIG. 1 is an exploded perspective view of a single-lens reflex camera interchangeable lens 1 (hereinafter simply referred to as “interchangeable lens 1”) provided with a cam mechanism according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the interchangeable lens 1 (only the upper half is shown). In the following description, the incident side (left side in FIG. 2) of the interchangeable lens 1 in the optical axis Ax direction is referred to as the tip side, and the emission side (right side in FIG. 2) is referred to as the proximal side.

  The interchangeable lens 1 includes a mount 10, a mount holding ring 20, a focus operation ring 30, a support ring 40, a zoom cam ring 100, a zoom fixing ring 200, a third lens moving frame 300, a focus fixing ring 400, a second lens moving frame 500, A focus cam ring 600, nine cam followers 700 (three cam followers 700A, 700B, 700C), a focus linking plate 800, a zoom operation ring 50, a zoom operation rubber 60, and a first lens frame 70 are provided. These members (except for the cam follower 700 and the focus linking plate 800) are disposed concentrically on the optical axis Ax.

  The mount 10 is a mounting portion for detachably mounting the interchangeable lens 1 to an optical device such as a single-lens reflex camera, and is fixed to the mount holding ring 20. Also, the mount holding ring 20 is fixed to the flange portion 41 of the support ring 40. The focus operating ring 30 is rotatably held around the optical axis Ax between the mount holding ring 20 and the support ring 40. An arc-shaped elongated hole 42 centered on the optical axis Ax is formed on the wall surface of the support ring 40 on the mount 10 side. An elongated plate-like focus linking plate 800 is inserted into the long hole 42. The focus link plate 800 is fixed to the focus operation ring 30 at its base end, and rotates around the optical axis Ax along the elongated hole 42 in response to the turning operation of the focus operation ring 30.

  The support ring 40 is accommodated in the hollow portion of the zoom operation ring 50. An annular engagement groove 43 extending in the circumferential direction is provided at the proximal end of the outer peripheral surface of the support ring 40. Further, at the proximal end portion of the inner peripheral surface of the zoom operation ring 50, an annular engaging claw 52 extending in the circumferential direction that engages with the engagement groove 43 of the support ring 40 is formed. The engagement of the engagement claw 52 of the zoom operation ring 50 and the engagement groove 43 of the support ring 40 restricts the movement of the zoom operation ring 50 in the direction of the optical axis Ax with respect to the support ring 40, and the optical axis Only rotation around Ax is possible. Further, when the zoom operation ring 50 is operated manually, the zoom operation rubber 60 is put on the outer periphery of the zoom operation ring 50 so that the zoom operation ring 50 can be operated accurately without slippage.

  The zoom cam ring 100 is housed inside the support ring 40, and the zoom fixed ring 200 is housed inside the zoom cam ring 100. The zoom fixing ring 200 is fixed to the support ring 40 at its proximal end. The inner diameter of the zoom cam ring 100 is substantially the same size as the outer diameter of the zoom fixing ring 200, and the zoom cam ring 100 is supported rotatably around the optical axis Ax by the zoom fixing ring 200. In addition, a circumferentially extending annular engaging claw 101 formed at the proximal end of the inner peripheral surface of the zoom cam ring 100 is formed in the circumferential direction at the proximal end of the outer peripheral surface of the zoom fixing ring 200. By engaging with the engagement recess 201, the movement of the zoom cam ring 100 in the optical axis Ax direction is restricted.

  A circumferentially extending slot 44 is formed in the cylindrical portion of the support ring 40, and the zoom link shaft 81 is passed through the slot 44. An external thread formed at one end (the lower end in FIG. 2) of the zoom connecting shaft 81 is formed at the tip of the zoom cam ring 100 and thus is screwed into the screw 110 and fixed to the zoom cam ring 100. Further, the other end of the zoom link shaft 81 is fitted into and fixed to a hole 51 provided in the zoom operation ring 50. That is, the zoom operation ring 50 is connected to the zoom cam ring 100 via the zoom connection shaft 81, and the zoom cam ring 100 rotates around the optical axis Ax in conjunction with the rotation of the zoom operation ring 50. There is.

  In the hollow portion of the zoom cam ring 100, the third lens moving frame 300 and the focus fixing ring 400 are accommodated side by side at a predetermined interval in the optical axis Ax direction. Specifically, the third lens moving frame 300 is disposed on the proximal side, and the focus fixing ring 400 is disposed on the distal side. The third lens moving frame 300 is connected to the zoom fixing ring 200 so as to be movable along the cam hole 220 via the three cam followers 700A. Further, the focus fixing ring 400 is connected to the zoom cam ring 100 so as to be movable along the cam holes 120A and 120B via the three cam followers 700B.

  As shown in FIG. 1, the third lens 93 is held by the third lens moving frame 300. In addition, an aperture leaf 94 is attached to the third lens moving frame 300 on the tip end side of the third lens 93 using an aperture support plate 95.

  As described later, the cam follower 700A is fixed to the third lens moving frame 300 and engages with the cam hole 220 formed on the zoom fixing ring 200 and the cam hole 120A formed on the zoom cam ring 100. The cam holes 220 and 120A (and cam holes 120B described later) are respectively formed on substantially cylindrical wall portions of the respective cylindrical members (the zoom fixing ring 200 and the zoom cam ring 100).

  The cam follower 700A is restricted in the movable direction only in the optical axis Ax direction by the engagement with the cam hole 220 extending in the optical axis Ax direction. Further, due to the engagement of the cam follower 700A and the substantially spiral cam hole 120A formed in the zoom cam ring 100, the cam follower 700A is driven in the optical axis Ax direction in conjunction with the rotation of the zoom cam ring 100.

  Therefore, when the zoom operation ring 50 (zoom operation rubber 60) is rotated, the zoom link shaft 81 and the zoom cam ring 100 fixed to the zoom operation ring 50 rotate integrally with the zoom operation ring 50, and interlocked therewith. The third lens moving frame 300 (and the third lens 93) fixed to the cam follower 700A moves in the direction of the optical axis Ax, and the optical image can be enlarged or reduced (zooming).

  Similarly, the cam follower 700B is fixed to the focus fixing ring 400 and engages with the cam hole 220 formed on the zoom fixing ring 200 and the cam hole 120B formed on the zoom cam ring 100.

  The cam follower 700B is restricted in the movable direction only in the optical axis Ax direction by the engagement with the cam hole 220 extending in the optical axis Ax direction. Further, due to the engagement between the cam follower 700B and the substantially spiral cam hole 120B formed in the zoom cam ring 100, the cam follower 700B is driven in the optical axis Ax direction in conjunction with the rotation of the zoom cam ring 100.

  Therefore, when the zoom operation ring 50 (zoom operation rubber 60) is rotated, the zoom link shaft 81 and the zoom cam ring 100 fixed to the zoom operation ring 50 rotate integrally with the zoom operation ring 50, and interlocked therewith. The focus fixing ring 400 fixed to the cam follower 700B moves in the direction of the optical axis Ax.

  At this time, since the cam hole 120A engaged with the cam follower 700A and the cam hole 120B engaged with the cam follower 700B are cam holes of the same shape formed in parallel with each other, the third lens moving frame 300 (and The third lens 93) held by the three-lens moving frame and the focus fixing ring 400 (and the second lens 92 supported by the focus fixing ring 400 via the second lens moving frame 500) do not change the relative position. Move in the direction of the optical axis Ax.

  Inside the focus fixing ring 400, a second lens moving frame 500 is accommodated. The second lens moving frame 500 is movably connected to the focus fixing ring 400 via the three cam followers 700C. Further, the second lens 91 is held by the second lens moving frame 500.

  The distal end side portion of the focus fixing ring 400 is smaller in diameter than the proximal end portion. A focus cam ring 600 is placed on the tip end portion of the focus fixing ring 400.

  As shown in FIG. 2, a circumferentially extending annular engaging claw 610 formed at the tip of the inner peripheral surface of the focus cam ring 600 is formed at the tip of the outer peripheral surface of the focus fixing ring 400. It engages with an annular engagement groove 430 extending in the direction. Thereby, the movement of the focus cam ring 600 in the direction of the optical axis Ax is restricted with respect to the focus fixing ring 400, and only rotation around the optical axis Ax is possible.

  Also, the focus link shaft 82 is screwed into the screw 630 (FIG. 1) because an external thread formed at one end (the lower end in FIG. 2) is formed at the tip of the focus cam ring 600. It is fixed to Furthermore, the other end of the focus linking shaft 82 is inserted into a long hole 810 provided at the tip of the focus linking plate 800 and extending in the direction of the optical axis Ax. Thereby, the movable direction of the focus cam ring 600 with respect to the focus linking plate 800 is restricted only in the direction of the optical axis Ax.

  Further, the focus fixing ring 400 and the focus cam ring 600 are connected to the outer peripheral surface of the second lens moving frame 500 by three cam followers 700C fixed at equal intervals (120 ° intervals) in the circumferential direction.

  The first lens frame 70 holding the first lens 91 is fixed to the tip of the support ring 40.

  The cam follower 700C is fixed to the second lens moving frame 500, and engages with the cam hole 420 formed in the focus fixing ring 400 and the cam hole 620 formed in the focus cam ring 600. The cam follower 700C is restricted in the movable direction only in the optical axis Ax direction by the engagement with the cam hole 420 extending in the optical axis Ax direction. Further, due to the engagement between the cam follower 700C and the substantially spiral cam hole 620 formed in the focus cam ring 600, the cam follower 700C moves in the optical axis Ax direction in conjunction with the rotation of the focus cam ring 600.

  Therefore, when the focus operation ring 30 is turned, the focus link plate 800 fixed to the focus operation ring 30, the focus link shaft 82 engaged with the focus link plate 800, and the focus cam fixed to the focus link shaft 82 The ring 600 rotates with the focus operation ring 30, and the second lens moving frame 500 (second lens 92) fixed to the cam follower 700C in conjunction with this is driven in the direction of the optical axis Ax, and focus adjustment is possible become.

[Groove cam mechanism]
Next, a groove cam mechanism using the cam follower 700 (700A, 700B, 700C) according to the embodiment of the present invention will be described.

  The cam followers 700A, 700B and 700C have the same structure, the cam holes 120A, 120B and 620 have the same cross-sectional shape, and the cam hole 220 and the cam hole 420 also have the same cross-sectional shape. That is, the engagement relationship between the cam follower 700A and the cam hole 120A and the cam hole 220 is the engagement relationship between the cam follower 700B and the cam hole 120B and the cam hole 220, and the engagement between the cam follower 700C and the cam hole 620 and the cam hole 420. It is the same as the relationship. Hereinafter, the engagement relationship between the cam follower 700A and the cam hole 120A and the cam hole 220 will be described as a representative of these.

  As shown in FIG. 1, in the zoom cam ring 100, cam holes (guide groove holes) having a substantially spiral shape (that is, formed obliquely with respect to each of the optical axis Ax direction and the circumferential direction). Three pairs of 120A and 120B are provided. The cam holes 120A and 120B engage with the cam followers 700A and 700B, and restrict the moving direction of the cam followers 700A and 700B to guide the cam followers 700A and 700B in a predetermined direction. The cam followers 700A, 700B engage with one corresponding cam hole 120A, 120B, respectively. The three pairs of cam holes 120A and 120B are provided at equal intervals (120 ° intervals) in the circumferential direction. Further, the cam holes 120A and 120B of each pair are provided in parallel in the direction of the optical axis Ax at predetermined intervals.

  In the zoom fixing ring 200, three cam holes (guide groove holes) 220 extending in the optical axis Ax direction are provided at equal intervals (120 ° intervals) in the circumferential direction. The cam hole 220 is a slot which engages with the corresponding pair of the cam followers 700A and 700B, restricts the moving direction of the cam followers 700A and 700B, and guides the cam followers 700A and 700B in a predetermined direction. The cam hole 220 is formed to intersect the cam holes 120A and 120B.

  Further, on the outer periphery of the third lens moving frame 300, three female screws 310 for attaching the cam follower 700A are provided at equal intervals (120 ° intervals).

FIG. 3 is a view for explaining the arrangement of the cam follower 700A, the cam hole 120A, and the cam hole 220. As shown in FIG.
FIG. 4 is an enlarged view of the vicinity of the cam follower 700A of FIG.
FIG. 5 is a cross-sectional view of the cam hole 120A formed in the zoom cam ring 100. As shown in FIG.
FIG. 6 is a cross-sectional view of the cam hole 220 formed in the zoom fixing ring 200. As shown in FIG.
FIG. 7 is a cross-sectional view of the screw 310 formed on the third lens moving frame 300.
FIG. 8 is a cross-sectional view of the cam follower 700. As shown in FIG.

  As shown in FIGS. 3-5, the cam hole 120A has a wide cam groove (wide guide groove) 140 formed on the outer peripheral side (upper side in FIG. 5) of the zoom cam ring 100 and an inner peripheral side (wide guide groove) of the zoom cam ring 100. A narrow cam groove (narrow guide groove) 130 whose groove width is narrower than the wide cam groove 140 is formed on the lower side in FIG. That is, the wide cam groove 140 and the narrow cam groove 130 are joined, and a cam hole 120A penetrating the zoom cam ring 100 is formed.

  Further, as shown in FIG. 4, the narrow cam groove 130 is provided with a pair of side walls (a first raceway surface 131 and a second raceway surface 132). The wide cam groove 140 also has a pair of side walls (a first track surface 141 and a second track surface 142). The narrow cam groove 130 of the present embodiment is formed to be shifted in the groove width direction with respect to the wide cam groove 140, and the center locus 133 of the narrow cam groove 130 (the first track surface 131 and the second track surface 132 The middle) is offset from the center locus 143 of the wide cam groove 140 (middle of the first raceway surface 141 and the second raceway surface 142) toward the first raceway surface 141 by a predetermined distance. That is, the distance between the first raceway surface 131 of the narrow cam groove 130 and the first raceway surface 141 of the wide cam groove 140 is the same as the second raceway surface 132 of the narrow cam groove 130 and the second raceway surface 142 of the wide cam groove 140. It is shorter than the distance.

  Similarly, as shown in FIGS. 3, 4 and 6, the cam hole 220 has a wide cam groove 240 formed on the outer peripheral side (upper side in FIG. 6) of the zoom fixing ring 200 and an inner periphery of the zoom fixing ring 200. It is comprised from the narrow cam groove 230 whose groove width is narrower than the wide cam groove 240 formed in the side (lower side in FIG. 6).

  Further, as shown in FIG. 4, the narrow cam groove 230 is provided with a pair of side walls (a first track surface 231 and a second track surface 232). The wide cam groove 240 also has a pair of side walls (a first raceway surface 241 and a second raceway surface 242). The narrow cam groove 230 is formed to be shifted in the groove width direction with respect to the wide cam groove 240, and the central locus 233 of the narrow cam groove 230 (intermediate between the first track surface 231 and the second track surface 232) is wide. A predetermined distance is offset from the center locus 243 of the cam groove 240 (between the first raceway surface 241 and the second raceway surface 242) toward the second raceway surface 242. That is, the distance between the first raceway surface 231 of the narrow cam groove 230 and the first raceway surface 241 of the wide cam groove 240 is the second raceway surface 232 of the narrow cam groove 230 and the second raceway surface 242 of the wide cam groove 240. It is longer than the distance.

  Further, as shown in FIG. 8, the cam follower 700 includes a support 710, two rotating portions (first roller 720 and second roller 730), and a sliding portion (slider 740). As described later, in the cam follower 700A, the post 710 engages with the internal thread 310 of the third lens moving frame 300, and the first roller 720 engages with the wide cam groove 140 of the cam hole 120A formed in the zoom cam ring 100. The second roller 730 engages with the narrow cam groove 230 of the cam hole 220 formed in the zoom fixing ring 200, and the slider 740 forms the narrow cam groove 130 of the cam hole 120A formed in the zoom cam ring 100 and the zoom fixing ring It engages with the wide cam groove 240 of the cam hole 220 formed in 200 (FIG. 9, 10).

  Further, as shown in FIG. 8, a cylindrical first sliding surface 741 in contact with the wall surface (second raceway surface 132) of the narrow cam groove 130 and the wide cam groove 240 are provided on the outer peripheral surface of the slider 740. A cylindrical second sliding surface 742 is provided in contact with the second wall surface (second raceway surface 232) of the second. Between the first sliding surface 741 and the second sliding surface 742, a concave portion 743 not in contact with any of the zoom cam ring 100 and the zoom fixing ring 200 is formed.

  The support 710 is a substantially bolt-like member having a screw 711 formed at one end.

  The first roller 720 is an annular frame 721 formed of a structural material having no rubber elasticity (for example, a metal material such as stainless steel, or a plastic material such as polyacetal resin or PTFE (polytetrafluoroethylene) resin), and an elastomer And an annular elastic portion 722 formed of, for example, a rubber such as silicone or a thermoplastic elastomer. The elastic portion 722 is inserted into an annular groove formed on the outer peripheral surface of the frame 721 and supported by the frame 721. The outer diameter of the elastic portion 722 is larger than the outer diameter of the frame 721, and the outer peripheral surface of the elastic portion 722 protrudes from the outer peripheral surface of the frame 721. Therefore, the first roller 720 contacts the first raceway surface 141 of the wide cam groove 140 at the elastic portion 722. In addition, the head portion 713 of the support 710 is loosely fitted (gap fit) in the hollow portion of the frame 721, and the first roller 720 is rotatably supported by the support 710.

  The second roller 730 also includes an annular frame 731 formed of a structural material having no rubber elasticity, and an annular elastic portion 732 formed of an elastomer. The elastic portion 732 is inserted into an annular groove formed on the outer peripheral surface of the frame 731 and supported by the frame 731. The outer diameter of the elastic portion 732 is larger than the outer diameter of the frame 731, and the outer peripheral surface of the elastic portion 732 protrudes from the outer peripheral surface of the frame 731. Therefore, the second roller 730 contacts the raceway surface 231 of the narrow cam groove 230 at the elastic portion 732. In the hollow portion of the frame 731, a portion on the external thread portion 711 side of the cylindrical portion 712 of the support 710 is loosely fitted, and the second roller 730 is rotatably supported by the support 710.

  The slider 740 is an annular member formed of a structural material having no rubber elasticity. In the hollow portion of the slider 740, a portion on the head portion 713 side of the cylindrical portion 712 of the support 710 is firmly fitted (fixed), and the slider 740 is fixed to the support 710.

  That is, the cam follower 700 is configured such that the first roller 720 and the second roller 730 roll and the slider 740 slides.

  9 and 10 are cross-sectional views showing the connecting structure of the zoom cam ring 100, the zoom fixing ring 200, and the third lens moving frame 300, respectively, via the cam follower 700A. FIG. 9 shows a cross section perpendicular to the extension direction of the cam hole 120 (cam grooves 130 and 140), and FIG. 10 is perpendicular to the extension direction of the cam hole 220 (narrow cam groove 230, wide cam groove 240). Shows a cut surface by the

  As shown in FIGS. 3, 4, 9 and 10, the cam follower 700 </ b> A is screwed into the female screw 310 of the third lens moving frame 300 by screwing the male screw 711 of the support 710 into the third lens moving frame 300. It is attached. Further, the first roller 720 of the cam follower 700A engages with the wide cam groove 140 of the zoom cam ring 100, and the second roller 730 engages with the narrow cam groove 230 of the zoom fixing ring 200. In the slider 740 of the cam follower 700A, the portion on the first roller 720 side engages with the narrow cam groove 130 of the zoom cam ring 100, and the portion on the second roller 730 side engages with the wide cam groove 240 of the zoom fixing ring 200. Do.

  As described above, the cam hole 120 is the second cam groove 130 engaged with the first roller 720 (rolling portion) and the narrow cam groove 130 engaged with the slider 740 (sliding portion). It is offset to the track surface 132 side (right side in FIG. 5). The radius of the outer diameter of the first roller 720 (elastic portion 722) is longer than the distance from the center locus 133 of the narrow cam groove 130 to the first raceway surface 141 of the wide cam groove 140, and the center of the narrow cam groove 130 The distance from the trajectory 133 to the second raceway surface 142 of the wide cam groove 140 is shorter. In addition, the outer diameter of the slider 740 is slightly smaller than the groove width of the narrow cam groove 130.

  Therefore, when the cam follower 700A is mounted in the cam hole 120A, as shown in FIG. 9, the first roller 720 (elastic portion 722) contacts only the first raceway surface 141 of the wide cam groove 140, and the second raceway surface It will be in the state which does not contact 142. Further, the elastic portion 722 of the first roller 720 is compressed between the first raceway surface 141 and the frame 721 of the first roller 720. Then, the slider 740 is pressed against the second raceway surface 132 of the narrow cam groove 130 by the elastic restoring force of the elastic portion 722. As described above, since the outer diameter of the slider 740 is slightly smaller than the groove width of the narrow cam groove 130, the slider 740 contacts the narrow cam groove 130 only at the second raceway surface 132 and the first raceway surface 131 Do not touch

  Further, the cam hole 220 has the narrow cam groove 230 engaged with the second roller 730 (rolling portion) on the second raceway surface 242 side (in FIG. 6) with respect to the wide cam groove 240 engaged with the slider 740. Offset to the right). The radius of the outer diameter of the second roller 730 (elastic portion 732) is longer than the distance from the center locus 243 of the wide cam groove 240 to the first raceway surface 231 of the narrow cam groove 230, and the center of the wide cam groove 240. The distance from the trajectory 243 to the second raceway surface 232 of the narrow cam groove 230 is shorter. Also, the outer diameter of the slider 740 is slightly smaller than the groove width of the wide cam groove 240.

  Therefore, when the cam follower 700A is mounted in the cam hole 120A, as shown in FIG. 10, the second roller 730 (elastic portion 732) contacts only the first raceway surface 231 of the narrow cam groove 230, and the second raceway surface It will be in the state which does not contact with 232. Further, the elastic portion 732 of the second roller 730 is compressed between the first raceway surface 231 and the frame 731 of the second roller 730. Then, the slider 740 is pressed against the second raceway surface 242 of the wide cam groove 240 by the elastic restoring force of the elastic portion 732. As described above, since the outer diameter of the slider 740 is slightly smaller than the groove width of the wide cam groove 240, the slider 740 contacts only the second raceway surface 242 with the wide cam groove 240, and the first raceway surface 241 Do not touch

  In this manner, the cam follower 700A is configured by the elasticity of the elastic portions 722, 732 so that both side walls of the cam holes 120, 220 (the first raceway surface 141 of the wide cam groove 140 and the second raceway surface 132 of the narrow cam groove 130, or Since it is always in close contact with the first raceway surface 231 of the narrow cam groove 230 and the second raceway surface 242 of the wide cam groove 240, it can move along the cam holes 120, 220 smoothly without rattling.

  In addition, the slider 740 sliding against the cam holes 120 and 220 does not have rubber elasticity, and large elastic deformation does not occur. Therefore, the position of the third lens moving frame 300 with respect to the cam holes 120 and 220 (specifically, the second raceway surfaces 132 and 242) is stably maintained, and a remarkable increase in sliding resistance does not occur.

  Further, the contact area between each rolling portion (the first roller 720 and the second roller 730) and the first raceway surfaces 141 and 231 is increased by the elastic deformation of the elastic portions 722 and 732. Dynamic resistance increases. However, the increase in rolling resistance is small compared to the remarkable increase in the sliding resistance of the sliding portion due to the elastic deformation of the sliding portion (slider 740).

  Therefore, according to the groove cam mechanism of the present embodiment, smooth operation with no rattling and little resistance is realized.

  In the present embodiment, a cam track surface that engages with the cam follower is provided on the wall surface (inner peripheral surface) of the cam hole (cam groove). Of the four wall surfaces formed in the cam holes 120A and 120B (cam grooves 130 and 140), the two track surfaces that engage with the cam followers 700A and 700B are the first track surface 141 and the second track surface 132 only. is there. Further, among the four wall surfaces formed in the cam hole 220 (cam grooves 230 and 240), the raceway surfaces engaged with the cam followers 700A and 700B are only two of the first raceway surface 231 and the second raceway surface 242. is there. Accordingly, the zoom cam ring 100 does not necessarily have to be provided with two pairs of raceway surfaces facing each other in a cam hole (cam groove) shape, and only two raceway surfaces of the first raceway surface 231 and the second raceway surface 242 are provided. Just do it.

  Hereinafter, modifications of the cam follower 700 according to the embodiment of the present invention will be described.

First Modification
FIG. 11 is a longitudinal sectional view showing a cam follower 1700 according to a first modification of the embodiment of the present invention. The cam follower 1700 connects only the two cylindrical members of the zoom cam ring 100 and the third lens moving frame 300. Therefore, the cam follower 1700 of this modification does not include the second roller 730 engaged with the cam hole 220 of the zoom fixing ring 200, and the slider 1740 does not have the second sliding surface 742 engaged with the cam hole 220. . The axial length of the column 1710 and the slider 1740 in this modification is shorter than the column 710 and the slider 740 of the cam follower 700 by the thickness of the zoom fixing ring 200.

  In this modification, when the zoom cam ring 100 and the third lens moving frame 300 are relatively rotated around the optical axis Ax, the cam follower 1700 moves along the cam hole 120 extending in a substantially spiral shape, so the zoom cam ring 100 And the third lens moving frame 300 move in the optical axis Ax direction.

Second Modified Example
FIG. 12 is a longitudinal sectional view showing a cam follower 2700 according to a second modification of the embodiment of the present invention. The cam follower 2700 couples only the two cylindrical members of the zoom fixing ring 200 and the third lens moving frame 300. Therefore, the cam follower 2700 of this modification does not have the first roller 720 engaged with the cam hole 120 of the zoom cam ring 100, and the slider 2740 does not have the first sliding surface 741 engaged with the cam hole 120. The axial length of the column 2710 and the slider 2740 in this modification is shorter than the column 710 and the slider 740 of the cam follower 700 by the thickness of the zoom cam ring 100.

  Also in this modification, when the zoom fixing ring 200 and the third lens moving frame 300 are relatively rotated around the optical axis Ax, the cam follower 2700 moves along the cam hole 220 extending in a substantially spiral shape, so the zoom cam ring The lens 100 and the third lens moving frame 300 move in the direction of the optical axis Ax.

  The above is a description of an exemplary embodiment of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of the present invention. For example, contents obtained by appropriately combining the embodiments explicitly illustrated in the specification or the obvious embodiments are also included in the embodiments of the present invention.

  In the above embodiment, the cam follower is fixed to the member on the inner circumferential side and is engaged with the cam hole formed in the member on the outer circumferential side (for example, the third lens moving frame is the cam follower 700A) (Fixed to 300 and engaged with the cam hole 120A of the zoom cam ring 100.) Contrary to this configuration, the cam follower is fixed to the outer peripheral member and engaged with the cam hole formed on the inner peripheral member. It may be configured to

  Further, in the above embodiment, the roller itself of the cam follower is formed of an elastic body, but the present invention is not limited to this configuration. A member other than the roller (for example, a member supporting the roller) may be an elastic member. Further, in the above embodiment, a member having rubber elasticity is used, but a spring (for example, a ring spring such as a wire ring) having an appropriate elastic force depending on the shape may be used.

  The above embodiment is an example in which the present invention is applied to the moving mechanism of the optical lens (single or plural) in the interchangeable lens for single-lens reflex camera, but optical elements other than the optical lens and the optical lens group Optical filters (in addition to wavelength filters, including polarizing elements such as polarizing filters and wavelength plates), mirrors, prisms, diffraction gratings, optical waveguides, nonlinear optical elements, photoelectric conversion elements (including solid-state imaging elements), LD [laser The present invention can be applied to a mechanism for moving a light source such as a diode] and other various optical elements.

  Furthermore, the present invention is not limited to interchangeable lenses for single-lens reflex cameras, but also dedicated televisions (CCTV [closed-circuit television]) such as compact cameras (lens integrated cameras), video cameras, surveillance cameras, lenses for CCTV, projectors It can be applied to projection devices, telescopes, microscopes, and other optical devices in general.

Reference Signs List 10 mount 20 mount holding ring 30 focus operation ring 40 support ring 50 zoom operation ring 60 zoom operation rubber 70 first lens frame 100 zoom cam ring 110 female screw 120 cam hole 130 narrow cam groove 140 wide cam groove 200 zoom fixed ring 220 cam hole 230 Narrow cam groove 240 Wide cam groove 300 Third lens moving frame 400 Focus fixed ring 500 Second lens moving frame 600 Focus cam ring 700 Cam follower 800 Focus link plate

Claims (10)

An optical element,
A cam mechanism for driving the optical element in the optical axis direction;
Equipped with
The cam mechanism is
The first orbital plane,
A second raceway surface provided on the side facing the first raceway surface;
A cam follower in contact with the first raceway surface and the second raceway surface;
The cam follower is
A rolling portion rolling on the first raceway surface;
A sliding portion sliding on the second raceway surface,
Optical equipment. The rolling portion has rubber elasticity,
The cam follower is sandwiched between the first raceway surface and the second raceway surface, and the sliding portion is pressed against the second raceway surface by an elastic restoring force of the rolling portion.
An optical apparatus according to claim 1. The cam mechanism includes a wall portion in which a cam hole is formed,
The first raceway surface and the second raceway surface are formed on an inner peripheral surface of the cam hole,
The optical apparatus according to claim 1 or 2. The cam hole is
A narrow cam groove formed on one side of the wall;
A wide cam groove formed on the other surface side of the wall portion and having a groove width wider than the narrow cam groove;
The first raceway surface is formed in one of the narrow cam groove and the wide cam groove;
The second raceway surface is formed on the other of the narrow cam groove and the wide cam groove,
The central track of the narrow cam groove and the wide cam groove are mutually offset in the groove width direction,
The optical apparatus according to claim 3. A first annular member to which the cam follower is attached;
A second annular member formed with the first raceway surface and the second raceway surface and disposed concentrically with the first annular member;
Equipped with
The optical apparatus according to any one of claims 1 to 4. It further comprises a third annular member formed with the first raceway surface and the second raceway surface and disposed concentrically with the first annular member.
The rolling portion is
A first rolling portion rolling on a first raceway surface of the second annular member;
And a second rolling portion rolling on a first raceway surface of the third annular member,
The sliding portion is
A first sliding portion sliding on a second raceway surface of the second annular member;
And a second sliding portion sliding on a second raceway surface of the third annular member.
The optical apparatus according to claim 5. The sliding portion is integrally formed,
The optical apparatus according to claim 6. A recess not in contact with the second annular member and the third annular member between a first sliding surface sliding with the second annular member and a second sliding surface sliding with the third annular member Was formed,
The optical apparatus according to claim 7. A cam mechanism for driving an optical element in the optical axis direction,
A first ring having a guide groove;
A cam follower fitted with the guide groove;
A second ring to which the cam follower is fixed;
Equipped with
The guide groove is
An inner circumferential groove formed on the inner circumferential side of the first ring;
An outer peripheral groove portion formed on the outer peripheral side of the first ring, the outer peripheral groove portion being offset in the groove width direction with respect to the inner peripheral groove portion;
The cam follower is
With a pillar,
A roller rotatably supported on the support;
And a slider fixed to the post.
The roller is in contact with the wall surface of the inner peripheral groove and one groove of the outer peripheral groove,
The slider contacts the wall surface of the other groove of the inner circumferential groove and the outer circumferential groove;
The radius of the roller before the cam follower is fitted in the guide groove is larger than the distance from the center locus of the other groove to the wall surface of the one groove.
Cam mechanism. A cam mechanism for driving an optical element in the optical axis direction,
A first ring having a first guiding groove;
A second ring having a second guide groove extending in a direction intersecting the guide groove;
A cam follower fitted to the first guide groove and the second guide groove;
A moving frame to which the cam follower is fixed;
Equipped with
Each of the first guide groove and the second guide groove is
An inner circumferential groove formed on the inner circumferential side of the first ring and the second ring ;
An outer circumferential groove formed on the outer circumferential side of the first ring and the second ring with an offset in the groove width direction with respect to the inner circumferential groove;
The cam follower is
With a pillar,
A first roller rotatably supported by the support and in contact with the first guide groove;
A second roller rotatably supported on the support and in contact with the second guide groove;
And a slider fixed to the post.
The first roller is in contact with the inner circumferential groove of the first guide groove and the wall surface of one groove of the outer circumferential groove.
The second roller is in contact with the inner circumferential groove of the second guide groove and the wall surface of one groove of the outer circumferential groove.
The slider
A wall surface of the other groove of the inner circumferential groove and the outer circumferential groove of the first guide groove;
Contact with the inner circumferential groove of the second guide groove and the wall surface of the other groove of the outer circumferential groove,
The radius of the first roller before the cam follower is fitted into the first guide groove is from the distance from the center locus of the other groove of the first guide groove to the wall surface of one groove of the first guide groove Too big,
The radius of the second roller before the cam follower is fitted into the second guide groove is from the distance from the center locus of the other groove of the second guide groove to the wall surface of one groove of the second guide groove Too big,
Cam mechanism.

Images