JP2014085485A - Lens barrel, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve impact resistance of a lens barrel.SOLUTION: A lens barrel includes: a holding member that has one of a drive cam groove and a drive cam pin which engage with each other to transmit a drive force, and holds an optical member; a drive member that has the other of the drive cam groove and the drive cam pin, and moves the holding member in an optical axis when the drive member is rotated around the optical axis of an optical member; an impact resistance piece that is provided in one of the holding member and the drive member; and a an impact resistance cam groove that is provided in the other of the holding member and the drive member to engage with the impact resistance piece, and has a cam face including a contact section in contact with a contact face of the impact resistance piece when the holding member is subjected to impact from an outside. An angle formed with a face having the impact resistance cam groove provided in the holding member or the drive member and the cam face of the impact resistance groove is larger than that in a section other than the contact section in the contact section.

Description

  The present invention relates to a lens barrel and an imaging apparatus.

There is a lens barrel in which a sharp surface that comes into contact when receiving an impact or the like is provided on a part of a cam pin having a taper (see Patent Document 1).
[Patent Document 1] Japanese Patent Application Laid-Open No. 2010-032970

  There is a trade-off between improving the strength of the cam pin and cam surface against impact and improving the positioning accuracy of the lens by the cam.

  According to the first aspect of the present invention, it has one of a drive cam groove and a drive cam pin that engage with each other to transmit a driving force, and has a holding member that holds an optical member, and the other of the drive cam groove and the drive cam pin. And a driving member that moves the holding member in the optical axis direction when rotated around the optical axis of the optical member, an impact-resistant piece provided on one of the holding member and the driving member, and the other of the holding member and the driving member. An impact-resistant cam groove having a cam surface that includes a contact section that is formed and engages with the impact-resistant piece, and that contacts the contact surface of the impact-resistant piece when the holding member receives an impact from the outside. Alternatively, a lens barrel is provided in which the angle formed by the surface of the drive member provided with the impact cam groove and the cam surface of the impact cam groove is larger in the contact section than in the sections other than the contact section.

  According to the second aspect of the present invention, there is provided an imaging apparatus including the lens barrel.

  The above summary of the present invention does not enumerate all necessary features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a schematic cross-sectional view of a single-lens reflex camera 100. FIG. 2 is a schematic cross-sectional view of a lens unit 200. FIG. 2 is a partial exploded perspective view of a lens unit 200. FIG. It is a perspective view which shows the front tube 204 independently. It is a perspective view which shows the cam cylinder 205 independently. FIG. 4 is a side view showing a front tube 204 and a cam tube 205 extracted. FIG. 6 is a schematic diagram showing a relationship between a cam cylinder 205 and a front cylinder 204. FIG. 6 is a schematic diagram showing a relationship between a cam cylinder 205 and a front cylinder 204. 6 is a schematic diagram showing a cam profile in a cam cylinder 205. FIG. It is a figure which shows the detailed shape of the impact cam groove 299. FIG. 3 is a perspective view of an impact resistant piece 289. FIG. It is sectional drawing of the impact-resistant piece 289. FIG. 3 is a perspective view of an impact resistant piece 289. FIG. It is sectional drawing of the impact-resistant piece 289. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention. The following embodiments do not limit the invention according to the claims. Not all combinations of features described in the following embodiments are essential for the solution of the invention.

  FIG. 1 is a schematic cross-sectional view of a single-lens reflex camera 100. The single-lens reflex camera 100 includes a lens unit 200 and a camera body 300. For the purpose of simplifying the description, in the following description, the object side with respect to the lens unit 200 attached to the camera body 300 is described as the front side or the front side of the single-lens reflex camera 100. Further, the side far from the object with respect to the lens unit 200 is referred to as a rear side or a back side in the single-lens reflex camera 100.

  The lens unit 200 has an optical system including a first lens group 210, a second lens group 220, a third lens group 230, and a fourth lens group 240 arranged along the optical axis Z. The first lens group 210, the second lens group 220, the third lens group 230, and the fourth lens group 240 are individually held by individual lens holding frames 212, 222, 232, and 242, respectively.

  The illustrated lens unit 200 is in a retracted state in which the first lens group 210, the second lens group 220, the third lens group 230, and the fourth lens group 240 are close to each other. Thereby, the length of the lens unit 200 in the optical axis Z direction is shortened and the portability is improved, but the function as the optical device cannot be used.

  The lens unit 200 includes a lens barrel including a fixed cylinder 201, an operation ring 202, a rectilinear cylinder 203, a front cylinder 204, a cam cylinder 205, a guide cylinder 206, a first moving frame 207 and a second moving frame 209. The fixed cylinder 201 has a lens side mount 208 at the rear end. The fixed cylinder 201 is coupled to the camera body 300 by coupling the lens side mount unit 208 to the body side mount unit 360 on the front surface of the camera body 300.

  The coupling between the lens side mount portion 208 and the body side mount portion 360 can be released. Therefore, the camera body 300 can be used in combination with another lens unit 200 having the lens side mount portion 208 that conforms to the standard.

  The operation ring 202 is arranged on the outer peripheral surface of the fixed cylinder 201, and is rotated about the optical axis Z of the optical system as a rotation axis by a user operation. The operation ring 202 is engaged with the rectilinear cylinder 203 and the cam cylinder 205 by a cam groove, a straight groove, or the like formed on the inner surface. The rectilinear cylinder 203 moves in the optical axis Z direction with respect to the fixed cylinder 201. Also, the cam cylinder 205 moves in the optical axis Z direction along with the rectilinear cylinder 203 while rotating together with the operation ring 202.

  The guide cylinder 206 located inside the cam cylinder 205 is coupled to the fixed cylinder 201 and does not move relative to the fixed cylinder 201. Therefore, the cam cylinder 205 also moves in the optical axis Z direction with respect to the guide cylinder 206.

  The front tube 204 is engaged with and supported by the straight tube 203 and the cam tube 205. As a result, the leading cylinder 204 moves in the optical axis Z direction in accordance with the movement of the rectilinear cylinder 203 and the cam cylinder 205 relative to the fixed cylinder 201.

  Further, the leading cylinder 204 is driven between a rectilinear cylinder 203 that moves in the optical axis Z direction without rotating and a cam cylinder 205 that moves in the optical axis Z direction while rotating, and the rectilinear cylinder 203 and the cam cylinder are driven. Also move to 205. Since the front tube 204 supports the lens holding frame 212 that holds the first lens group 210 at the tip, the first lens group 210 also moves as the front tube 204 moves.

  The first moving frame 207 and the second moving frame 209 have cam pins 283 and 284 that engage with cam grooves formed in the cam cylinder 205, respectively. It moves individually in the optical axis Z direction. Accordingly, the first moving frame 207 moves the lens holding frame 222 holding the second lens group 220 in the optical axis light direction. The second moving frame 209 indirectly or directly connects the lens holding frames 232 and 242 that hold the third lens group 230 and the fourth lens group 240, so that the third lens group 230 and the fourth lens group are connected. 240 is moved in the optical axis Z direction.

  Furthermore, the lens holding frame 232 that holds the third lens group 230 is driven by a feed screw assembly 270 that is fixed to the lens holding frame 242 that holds the fourth lens group 240, and further to the lens holding frame 242. It is supported movably. The feed screw assembly 270 includes a stepping motor 272, a feed screw 274 and a frame 276.

  The frame 276 integrally supports the stepping motor 272 and the feed screw 274 and is fixed to the lens holding frame 242. The stepping motor 272 drives the feed screw 274 to rotate. The feed screw 274 engages with the lens holding frame 232 via the rack member 278.

  Thereby, the third lens group 230 held by the lens holding frame 232 can be moved relative to the lens holding frame 242 holding the fourth lens group 240. When the third lens group 230 moves in the lens unit 200, the focal position of the optical system of the lens unit 200 changes. Therefore, the lens unit 200 can be focused by electrically controlling the stepping motor 272 based on the signal from the camera body 300 side.

  The camera body 300 includes a mirror unit 370 disposed behind the body side mount portion 360. A focusing optical system 380 is disposed below the mirror unit 370. A focusing screen 352 is disposed above the mirror unit 370.

  A pentaprism 354 is disposed further above the focusing screen 352, and a finder optical system 356 is disposed behind the pentaprism 354. The rear end of the viewfinder optical system 356 is exposed as a viewfinder 350 on the back surface of the camera body 300.

  Behind the mirror unit 370, a shutter unit 310, a low-pass filter 332, an image sensor 330, a substrate 320, and a display unit 340 are sequentially arranged. A display unit 340 formed by a liquid crystal display panel or the like appears on the back surface of the camera body 300. A control unit 322, an image processing unit 324, and the like are mounted on the substrate 320.

  The mirror unit 370 includes a main mirror 371 and a sub mirror 374. The main mirror 371 is supported by a main mirror holding portion 372 that is pivotally supported by a main mirror rotating shaft 373.

  The sub mirror 374 is supported by a sub mirror holding portion 375 that is pivotally supported by a sub mirror rotating shaft 376. The sub mirror holding unit 375 rotates with respect to the main mirror holding unit 372. Therefore, when the main mirror holding part 372 rotates, the sub mirror holding part 375 is also displaced together with the main mirror holding part 372.

  When the front end of the main mirror holding portion 372 is lowered, the main mirror 371 is positioned obliquely on the incident light beam incident from the lens unit 200. When the main mirror holding part 372 moves up, the main mirror 371 retracts to a position avoiding the incident light beam.

  When the main mirror 371 is positioned on the incident light beam, the incident light beam incident through the lens unit 200 is reflected by the main mirror 371 and guided to the focusing screen 352. The focusing screen 352 is disposed at a position conjugate with the optical system of the lens unit 200, and visualizes an image formed by the optical system of the lens unit 200.

  The image on the focusing screen 352 is observed from the viewfinder 350 through the pentaprism 354 and the viewfinder optical system 356. Here, an erect image can be observed from the viewfinder 350 by observing the image through the pentaprism 354.

  The photometric sensor 390 is disposed above the finder optical system 356 and receives a part of the branched incident light beam. The photometric sensor 390 detects the subject brightness and causes the control unit 322 to calculate an exposure condition that is a part of the photographing condition.

  The main mirror 371 has a half mirror region that transmits a part of the incident light beam. The sub mirror 374 reflects a part of the incident light beam incident from the half mirror region toward the focusing optical system 380. The focusing optical system 380 guides a part of the incident incident light beam to the focus detection sensor 382. Thereby, the control unit 322 determines the target position of the lens that moves when the optical system of the lens unit 200 is focused.

  When the release button is half-pressed in the single-lens reflex camera 100 including the lens unit 200 and the camera body 300 as described above, the focus detection sensor 382 and the photometric sensor 390 are enabled, and a subject image can be taken under appropriate shooting conditions. It becomes a state. Next, when the release button is fully pressed, the main mirror 371 and the sub mirror 374 move to the retracted position, and the shutter unit 310 is opened. Thereby, the incident light beam incident from the lens unit 200 passes through the low-pass filter 332 and enters the image sensor 330.

  FIG. 2 is a partial cross-sectional view showing another state of the lens unit 200, and shows a cross section of the lens unit 200 that is scaled to the wide-angle side on the upper side in the drawing with respect to the optical axis Z. Further, in FIG. 2, a cross section of the lens unit 200 that is zoomed to the telephoto side is shown below the optical axis Z in the drawing.

  In FIG. 2, the same reference numerals are assigned to the same elements as those in FIG. However, although FIG. 2 is common to FIG. 1 in that it is a cross-section including the optical axis Z, a cross-section different from FIG. 1 is shown. May appear in different shapes.

  In the lens unit 200, the rectilinear cylinder 203 is engaged with the operation ring 202 in the lead portion 280. Since the rectilinear cylinder 203 is prevented from rotating with respect to the fixed cylinder 201, when the operation ring 202 is rotated, the driving cylinder 202 receives a driving force that moves in the optical axis Z direction from the operation ring 202.

  The cam cylinder 205 is engaged in the vicinity of the rear end of the rectilinear cylinder 203 by a bayonet claw 286 disposed in the vicinity of the rear end of the cam cylinder 205. The bayonet claw 286 engages with the bayonet groove extending in the circumferential direction on the inner surface of the rectilinear cylinder 203, so that the cam cylinder 205 can rotate around the optical axis Z. However, when the rectilinear cylinder 203 moves in the optical axis Z direction, the cam cylinder 205 also moves in the optical axis direction along with the rectilinear cylinder 203. In other words, the cam cylinder 205 and the rectilinear cylinder 203 are engaged only in the optical axis Z direction.

  The cam cylinder 205 is engaged with a groove provided in the inner surface of the operation ring 202 in parallel with the optical axis Z through a connecting pin 285 fixed to the outer peripheral surface of the cam cylinder 205. Thereby, when the operation ring 202 is rotated, the cam cylinder 205 is also rotated.

  As already described, when the operation ring 202 is rotated, the rectilinear cylinder 203 moves in the direction of the optical axis Z, and the cam cylinder 205 moves along with the rectilinear cylinder 203. Therefore, when the operation ring 202 is rotated, the cam cylinder 205 moves in the optical axis Z direction while rotating around the optical axis Z.

  The guide tube 206 is positioned inside the cam tube 205 and is coupled to the fixed tube 201 and fixed. Therefore, when the operation ring 202 is rotated, the rectilinear cylinder 203 and the cam cylinder 205 also move relative to the guide cylinder 206. Since the guide tube 206 extends toward the front end side of the lens unit 200 in the direction of the optical axis Z, the guide tube 206 supports the cam tube 205 from the inner surface side and is associated with a key 287 provided at the rear end of the rectilinear tube 203. The rectilinear groove 288 is joined to suppress the rotation of the rectilinear cylinder 203.

  The front tube 204 supports the lens holding frame 212 of the first lens group 210 at the tip. Further, the front tube 204 is engaged with and supported by the rectilinear tube 203 and the cam tube 205 by the drive cam pin 281 and the like. Therefore, when the rectilinear cylinder 203 and the cam cylinder 205 move in the optical axis Z direction, the leading cylinder 204 moves accordingly in the optical axis Z direction.

  Further, when the operation ring 202 is rotated, the front tube 204 is moved between the rectilinear tube 203 that moves in the optical axis Z direction without rotating and the cam tube 205 that moves in the optical axis Z direction while rotating. When driven, the linearly moving cylinder 203 and the cam cylinder 205 are also moved in the optical axis Z direction. As a result, the first lens group 210 held at the tip of the front tube 204 is largely extended forward from the fixed tube 201.

  As described above, when the operation ring 202 is rotated, the first lens group 210, the second lens group 220, the third lens group 230, and the fourth lens group 240 individually move with respect to the fixed barrel 201. . Thereby, the magnification of the optical system formed in the lens unit 200 changes according to the rotation amount of the operation ring 202. Further, when the operation ring 202 is rotated beyond the zooming range of the lens unit 200, the lens unit 200 is in a retracted state.

  FIG. 3 is an exploded perspective view of a part of the lens unit 200. FIG. 3 shows a fixed cylinder 201, a guide cylinder 206, an operation ring 202, a rectilinear cylinder 203, and a cam cylinder 205. Elements common to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  The guide tube 206 has a plurality of positioning portions 295 that protrude outward in the radial direction. As a result, the guide tube 206 is positioned at a predetermined position inside the fixed tube 201 and is fixed to the fixed tube 201. The guide cylinder 206 is fixed to the fixed cylinder 201 by, for example, screwing.

  A plurality of lead grooves 294 are arranged on the outer peripheral surface of the guide tube 206. The lead groove 294 engages with a lead portion provided on the inner surface of the cam cylinder 205. Thereby, when the operation ring 202 is rotated and the cam cylinder 205 moves in the optical axis Z direction while rotating with respect to the fixed cylinder 201, the movement path of the cam cylinder 205 is guided.

  Further, a rectilinear groove 288 extending in the optical axis Z direction is disposed on the outer peripheral surface of the guide tube 206. The rectilinear groove 288 engages with a key 287 provided at the rear end of the rectilinear cylinder 203 and restricts rotation while allowing the rectilinear cylinder 203 to move in the optical axis Z direction.

  In the assembled lens unit 200, a cam cylinder 205 is disposed outside the guide cylinder 206. The cam cylinder 205 has a plurality of bayonet claws 286 protruding in the radial direction in the vicinity of the rear end of the outer peripheral surface of the cam cylinder 205. The bayonet claw 286 engages with a bayonet groove arranged in the circumferential direction on the inner surface near the rear end of the rectilinear cylinder 203. Thereby, the cam cylinder 205 is coupled to the rectilinear cylinder 203 in the optical axis Z direction while being allowed to rotate with respect to the rectilinear cylinder 203.

  A connecting pin 285 is screwed to the outer peripheral surface of the cam cylinder 205. The connecting pin 285 protrudes from the cam cylinder 205 toward the radially outer side of the cam cylinder 205.

  In addition, a plurality of cam groove groups in which a pair of drive cam grooves 291 and a single impact cam groove 299 are combined are arranged on the outer peripheral surface of the cam cylinder 205. In each cam groove group, the pair of drive cam grooves 291 are disposed with a single impact cam groove 299 interposed therebetween.

  In the assembled lens unit 200, a rectilinear cylinder 203 is disposed outside the cam cylinder 205. However, in the lens unit 200, a front tube 204 is disposed between the cam tube 205 and the rectilinear tube 203.

  The rectilinear cylinder 203 has a bayonet groove on the inner surface that engages with the bayonet claw 286 of the cam cylinder 205. The bayonet groove extends in the circumferential direction on the inner surface of the rectilinear cylinder 203, and a part thereof is notched in the optical axis Z direction. As a result, when the rectilinear cylinder 203 is mounted outside the cam cylinder 205, the bayonet claw 286 of the cam cylinder 205 can be fitted in the bayonet groove in the optical axis Z direction.

  The rectilinear cylinder 203 has a rectilinear groove 297 provided in the optical axis Z direction. The rectilinear groove 297 engages with a part of the front tube 204 and restricts the rotation of the front tube 204 around the optical axis Z.

  Further, the rectilinear cylinder 203 has a plurality of lead portions 292 in the vicinity of the rear end of the outer peripheral surface. The lead portion 292 protrudes outward in the radial direction of the rectilinear cylinder 203. Note that when extended forward, the front end side of the outer peripheral surface of the rectilinear cylinder 203 is exposed toward the outside of the lens unit 200. Therefore, the surface and front end of the rectilinear cylinder 203 are finished flat without providing grooves, protrusions, notches, and the like.

  The operation ring 202 is attached to the outermost periphery of the lens unit 200 and rotates with respect to the fixed cylinder 201. A plurality of spiral lead grooves 293 are arranged on the inner surface of the operation ring 202. When the operation ring 202 is attached to the lens unit 200, the lead groove 293 engages with the lead portion 292 of the rectilinear cylinder 203.

  In the lens unit 200 including the fixed cylinder 201, the operation ring 202, the rectilinear cylinder 203, the cam cylinder 205, and the guide cylinder 206 as described above, the lead portion 292 of the rectilinear cylinder 203 is disposed near the rear end of the rectilinear cylinder 203. Has been. Further, the lead groove 293 extends to the inner surface front end of the operation ring 202. Therefore, the rectilinear cylinder 203 can be extended to a length close to its entire length, and the magnification of the lens unit 200 can be increased.

  In addition, since a plurality of lead portions 292 that engage with the lead grooves 293 are provided on the circumference of the rectilinear cylinder 203, the positioning of the rectilinear cylinder 203 by the operation ring 202 is stabilized. Further, the rectilinear cylinder 203 is a linear advance of the guide cylinder 206 fixed to the fixed cylinder 201 at a plurality of keys 287 (see FIG. 2) provided on the inner surface of the rearmost end separated from the position of the lead portion 292 in the optical axis Z direction. Engage with the groove 288. Therefore, it is possible to prevent the inclination of the rectilinear cylinder 203 with respect to the optical axis Z from shifting.

  Furthermore, since the inclination of the rectilinear cylinder 203 with respect to the fixed cylinder 201 is stabilized, a change in the inclination of the front cylinder 204 supported by the rectilinear cylinder 203 with respect to the optical axis is also suppressed. Therefore, even if the straight cylinder 203 and the front cylinder 204 are extended in two stages, the optical performance of the lens unit 200 is unlikely to change. As a result, a high-magnification variable power lens unit that stably exhibits high optical performance can be provided. In other words, it is possible to form the lens unit 200 with higher magnification while maintaining the optical performance.

  FIG. 4 is a perspective view showing the front tube 204 alone. Elements common to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  The front tube 204 has three rectilinear pieces 282 near the rear end of the outer peripheral surface. The three rectilinear pieces 282 are arranged at equal intervals in the circumferential direction of the front tube 204. In the lens unit 200, the rectilinear piece 282 engages with a rectilinear groove 297 formed on the inner surface of the rectilinear cylinder 203. Thereby, the rotation of the front tube 204 with respect to the rectilinear tube 203 is restricted. Since the rectilinear cylinder 203 is also restricted from rotating relative to the fixed cylinder 201, the leading cylinder 204 is also restricted from rotating relative to the fixed cylinder 201.

  Further, the front tube 204 has a plurality of drive cam pins 281 and impact resistant pieces 289 in the vicinity of the rear end of the inner surface. The three impact resistant pieces 289 are arranged at equal intervals in the circumferential direction of the front tube 204. Each of the impact resistant pieces 289 has an upstanding peripheral surface that is nearly parallel to the radial direction of the front tube 204. Further, the peripheral surface of each of the impact resistant pieces 289 includes a pair of planes orthogonal to the optical axis Z of the lens unit.

  The drive cam pins 281 are a set of two, and each pair of drive cam pins 281 is arranged with one impact-resistant piece 289 interposed therebetween. Each peripheral surface of the drive cam pin 281 has a constant inclination with respect to the radial direction of the leading tube 204, following the inclination of the cam surface of the drive cam groove 291. As a result, the front tube 204 is equally supported in the circumferential direction from the rectilinear tube 203 and the cam tube 205 and is equally transmitted with the driving force. As a result, the front tube 204 is accurately positioned with respect to the cam tube 205 in the optical axis Z direction, and a driving force is transmitted from the drive cam groove 291 so as to be driven in the optical axis Z direction.

  FIG. 5 is an enlarged perspective view showing the cam cylinder 205 alone. Elements that are the same as those in FIG. 3 are given the same reference numerals, and redundant descriptions are omitted.

  The cam cylinder 205 includes three sets of cam grooves, each of which includes a pair of drive cam grooves 291 and one impact cam groove 299. One end of the drive cam groove 291 has a groove end opening 290 connected to the end face in the optical axis direction of the cam cylinder 205. When the lens unit 200 is assembled, the drive cam pin 281 and the impact resistant piece 289 of the front tube 204 are inserted into the drive cam groove 291 and the impact resistant cam groove 299 through the groove end opening 290.

  Note that in one set of cam groove groups formed by a pair of drive cam grooves 291 and one shock-resistant cam groove 299, one drive cam groove 291 and shock-resistant cam groove 299 share the groove end opening 290. Thereby, the area of the thin part of the cam cylinder 205 can be reduced, and the strength of the cam cylinder 205 can be improved.

  FIG. 6 is a side view showing the front tube 204 and the cam tube 205 together. Elements that are the same as those in FIG. 5 are given the same reference numerals, and redundant description is omitted.

  In the lens unit 200, the cam cylinder 205 enters the inside of the front cylinder 204. As a result, the drive cam pin 281 of the front tube 204 is engaged with the drive cam groove 291 of the cam tube 205. Further, the impact resistant piece 289 of the front tube 204 is engaged with the impact resistant cam groove 299 of the cam tube 205.

FIG. 7 is a developed view schematically showing the operational relationship between the cam cylinder 205 and the front cylinder 204 shown in FIG. In the state shown in the drawing, the front end of the front tube 204 protrudes forward to the length L ₁ from the cam tube 205. At this time, the drive cam pin 281 of the front tube 204 is engaged with the relatively upper portions of the drive cam groove 291 and the shock resistant cam groove 299 of the cam tube 205, respectively. Further, the impact resistant piece 289 of the front tube 204 is also located relatively above the impact resistant cam groove 299.

  FIG. 8 is a development view schematically showing the operational relationship between the cam cylinder 205 and the front cylinder 204. In the state shown in the figure, the cam barrel 205 rotated from the state shown in FIG. 7 moves relatively upward in the figure. As a result, the drive cam pin 281 of the front tube 204 moves downward in the drawing within the drive cam groove 291 of the cam tube 205.

As described above, in the lens unit 200, the front tube 204 is restricted from rotating around the optical axis Z by the rectilinear piece 282. Therefore, when the drive cam pin 281 moves in the drive cam groove 291, it is driven in a direction parallel to the optical axis Z. Thus, in the illustrated example, the front cylinder 204 is fed forward to a length L _2, the magnification of the optical system of the lens unit 200 is changed. In addition, with the relative movement of the drive cam pin 281, the impact resistant piece 289 is also moved downward in the figure in the impact resistant cam groove 299.

  FIG. 9 is a schematic development view showing a profile in the cam cylinder 205. FIG. 9 shows a set of cam groove groups including a pair of drive cam grooves 291 and a single impact cam groove 299.

  One of the drive cam grooves 291 located on the left side in the drawing and the shock resistant cam groove 299 are separated in the optical axis Z direction of the lens unit 200 and are disposed at the same position in the circumferential direction of the cam cylinder 205. . Further, the drive cam groove 291 and the shock resistant cam groove 299 share the opening 290 formed at the tip of the cam cylinder 205. Thereby, a plurality of cam grooves can be arranged in a limited area in the circumferential direction of the cam cylinder 205.

  The other drive cam groove 291 located on the right side in the drawing is displaced in the optical axis Z direction of the lens unit 200 and in the circumferential direction around the optical axis Z with respect to the one drive cam groove 291. . However, the pair of drive cam grooves 291 have the same profile. Therefore, the pair of drive cam grooves 291 can drive the front tube 204 in cooperation and can be positioned accurately.

  In each of the pair of drive cam grooves 291, the pair of cam surfaces that form the side walls have an inclination in which the interval becomes wider toward the outside in the radial direction of the lens unit 200. Such an inclination is formed in consideration of facilitating removal of the mold when the cam cylinder 205 is formed.

  In the drive cam groove 291, the angle formed by the cam surface inclined as described above with respect to the straight line perpendicular to the optical axis Z coinciding with the rotation axis of the cam cylinder 205 does not change over the entire length of the drive cam groove 291. Therefore, the follower surface formed on the side surface of the drive cam pin 281 that engages with the drive cam groove 291 also has a truncated cone shape having an inclination complementary to the inclination of the cam surface. Thereby, each of the drive cam pins 281 is always in linear contact with the corresponding drive cam groove 291.

  In each of the drive cam grooves 291, when the drive cam pin 281 is positioned at the upper end of the drive cam groove 291, the leading tube 204 is in the most retracted position. At this time, the lens unit 200 is in a retracted state.

  When the drive cam pin 281 moves relatively downward in the drawing in the drive cam groove 291, the leading tube 204 advances in the optical axis Z direction, and eventually reaches the wide-angle end where the magnification of the lens unit 200 is the lowest. When the driving cam pin 281 further moves downward in the figure from this state, the leading tube 204 further advances, and the magnification of the lens unit 200 gradually increases. In other words, when the drive cam pin 281 in the drive cam groove 291 is positioned between the retracted position and the wide angle end, the lens unit 200 cannot exhibit the desired optical characteristics.

  Subsequently, when the drive cam pin 281 moves downward in the drawing, the leading tube 204 further advances, and eventually reaches the telephoto end that has advanced most. Thereby, the magnification of the lens unit 200 becomes the highest.

  In each of the drive cam grooves 291, a portion formed before the telephoto end is formed for the purpose of communicating the drive cam groove 291 with the opening 290. Therefore, when the drive cam pin 281 reaches the telephoto end, the rotation of the operation ring 202 is restricted for the purpose of preventing the drive cam pin 281 from moving beyond the telephoto end.

  As described above, the lens unit 200 is an optical element that contributes to photographing by the single-lens reflex camera 100 when the driving cam pin 281 moves in the zooming section formed between the wide-angle end and the telephoto end in the driving cam groove 291. Performance. The movement of the drive cam pin 281 from the wide-angle end to the retracted position in the drive cam groove 291 causes the front tube 204 to be retracted for the purpose of retracting the lens unit 200, but is not related to the optical characteristics of the lens unit 200.

  Further, fine movement sections are provided at both ends of the zooming section in which the drive cam pin 281 is moved optically significantly in the drive cam groove 291. In the fine movement section, the inclination angle formed by the extending direction of the drive cam groove 291 with respect to the plane XY perpendicular to the optical axis Z of the lens unit 200 is relatively small compared to the other sections. For this reason, the movement amount of the front tube 204 is reduced with respect to the same rotation amount with respect to the operation ring 202 of the lens unit 200.

  The fine movement section on the telephoto end side prevents the cam cylinder 205 from being turned by the drive cam pin 281 moving in the optical axis Z direction when a load in the optical axis Z direction is applied to the front cylinder 204. It is provided for the purpose. This prevents the lens unit 200 from being contracted or expanded by its own weight when the front end of the lens unit 200 is directed upward in the gravity direction with the front tube 204 extended to the telephoto end.

  In the front tube 204, the relative position between the drive cam pin 281 and the impact resistant piece 289 is fixed. Therefore, in the cam cylinder 205, the overall profile of the impact cam groove 299 is parallel to the profile of the drive cam groove 291. Therefore, also in the impact cam groove 299, sections corresponding to the retracted position, the variable power section, the fine movement section, and the like are formed. However, the groove width of the impact resistant cam groove 299 and the inclination of the cam surface are not constant.

  As already described, the drive cam pin 281 is always in contact with the drive cam groove 291 to position the leading tube 204. However, the impact resistant piece 289 may be separated from the impact resistant cam groove 299 with a minimum clearance when the lens unit 200 is not impacted from the outside. Thereby, generation | occurrence | production of the sliding resistance of the impact-resistant piece 289 and the impact-resistant cam groove 299 can be avoided.

  Further, it is preferable that the impact resistant piece 289 that is separated from the cam surface inside the impact resistant cam groove 299 is close to the rear cam surface of the impact resistant cam groove 299. Thereby, when an impact is received from the front end side of the lens unit 200, the impact resistant piece 289 and the impact resistant cam groove 299 immediately come into contact with each other.

  FIG. 10 is a schematic diagram for explaining the shape of the shock resistant cam groove 299. The impact cam groove 299 extends in parallel with the drive cam groove 291. However, the impact resistant cam groove 299 includes portions having different cross-sectional shapes and groove widths. In FIG. 10, the shape of the cross section orthogonal to the extending direction of the impact-resistant cam groove 299 is shown individually at each position indicated by reference signs A to F.

  Note that the symbol A indicates a position closest to the position where the shock-resistant piece 289 exists when the drive cam pin 281 is located at the retracted position. Reference symbol B indicates a position where the shock-resistant piece 289 exists when the drive cam pin 281 is located in the fine movement section on the wide-angle end side. Reference numeral C indicates a position where the shock-resistant piece 289 is present when the drive cam pin 281 passes through the middle of the magnification changing section.

  Reference sign D indicates a position where the shock-resistant piece 289 exists when the drive cam pin 281 is at a position immediately before entering the fine movement section on the telephoto end side. Reference symbol E indicates a position where the shock-resistant piece 289 exists when the drive cam pin 281 is positioned in the fine movement section on the telephoto end side. Reference symbol F indicates a position where the shock-resistant piece 289 is present when the drive cam pin 281 is positioned in the opening 290.

  In FIG. 10, when attention is paid to the inclination of the cam surface forming the side wall in each cross section orthogonal to the extending direction of the shock resistant cam groove 299, that is, the angle formed by the cam surface with respect to the straight line orthogonal to the optical axis Z, the shock resistant The inclination of the cam surface varies depending on the extending direction of the cam groove 299. In the illustrated example, at the positions indicated by reference signs A, C, D, and F in the drawing, the expansion of the shock-resistant cam groove 299 due to the inclination of the cam surface is relatively large. For example, the pair of cam surfaces are 60 ° apart from each other. Make an angle. On the other hand, at the positions indicated by reference numerals B and E, the expansion of the impact-resistant cam groove 299 due to the inclination of the cam surface is relatively small. For example, the pair of cam surfaces form an angle of 16 ° with each other.

  Further, in each cross section, focusing on one of the pair of cam surfaces, the angle formed by the boundary between the surface of the cam cylinder 205 and the cam surface at a position where the inclination of the cam surface of the shock resistant cam groove 299 is large. Is relatively large. In the illustrated example, at the positions indicated by reference signs A, C, D, and F, the angle formed by the surface of the cam cylinder 205 and the cam surface is approximately 120 °.

  On the other hand, at the position where the cam surface of the impact resistant cam groove 299 stands upright, the angle formed by the boundary between the surface of the cam cylinder 205 and the cam surface is relatively small. In the illustrated example, the angle formed by the surface of the cam cylinder 205 and the cam surface is 98 ° at the positions indicated by symbols B and E.

  Note that, in the cross sections at the positions indicated by reference signs A, C, D, and F, the inclination of the cam surface of the impact cam groove 299 is substantially equal to the inclination of the cam surface of the drive cam groove 291. Such a cam surface having a relatively large inclination is formed when the shock-resistant cam groove 299 extends at a large angle with respect to the plane XY perpendicular to the optical axis Z of the lens unit 200. Easy to mold.

  On the other hand, the cam surface inclines in the cross section at the positions indicated by reference characters B and E, and is at an angle close to a right angle with respect to the bottom surface of the shock resistant cam groove 299. Such an impact resistant cam groove 299 is easy to mold when the extending direction of the impact resistant cam groove 299 is almost parallel to the plane XY perpendicular to the optical axis Z of the lens unit 200.

  In FIG. 10, paying attention to the groove width of the shock resistant cam groove 299 defined by the distance between the pair of cam surfaces, the groove width of the shock resistant cam groove 299 at the positions indicated by reference characters B and E in the figure is relatively different. Narrower than the position. In addition, the groove width of the impact resistant cam groove 299 at the positions indicated by reference signs A, C, and F in the drawing is wider than the groove width at the position indicated by reference sign D. Thereby, the movement of the non-circular impact resistant piece 289 is made smooth, and the strength and rigidity of the cam cylinder 205 are maintained.

  As described above, the impact-resistant cam groove 299 changes both the inclination of the cam surface and the groove width in accordance with the position in the longitudinal direction. In such an impact resistant cam groove 299, a contact section where the impact resistant piece 289 comes into contact is formed in a portion where the cam surface of the drive cam groove 291 is small.

  In the example shown in the drawing, a pair of contact sections are provided in the impact-resistant cam groove 299 at positions corresponding to both ends of the variable power section of the drive cam groove 291. In any of the contact sections, as indicated by the positions B and E in FIG. 10, the impact-resistant cam groove 299 has a narrow groove width, and the cam surface stands upright with respect to the surface of the cam cylinder 205.

  In the lens unit 200, the impact-resistant cam groove 299 as described above engages with an impact-resistant piece 289 provided in the front tube 204, as indicated by a dotted line in the drawing. The action of the impact resistant piece 289 with respect to the impact resistant cam groove 299 will be described again with reference to FIG. 10 after describing the shape of the impact resistant piece 289.

  FIG. 11 is a perspective view of an impact resistant piece 289 that engages with the impact resistant cam groove 299. In the shock-resistant piece 289, the rear surface (right front side in the drawing) in the direction of the optical axis Z forms a contact surface 400. The contact surface 400 contacts the cam surface of the impact resistant cam groove 299 when an impact is applied from the direction of the optical axis Z to the tip of the front tube 204 in the lens unit 200.

  FIG. 11 is also a diagram showing one cross section of the impact resistant piece 289. A plane Q shown in FIG. 11 is parallel to the optical axis Z in the lens unit 200 and substantially parallel to the inner peripheral surface of the front tube 204. Here, “substantially parallel” means that the inner peripheral surface of the front tube 204 is a cylindrical surface and cannot be said to be geometrically parallel to the plane Q.

  FIG. 12 shows the shape of the impact-resistant piece 289 in the cross section cut by the plane Q shown in FIG. The cross-sectional shape of the impact-resistant piece 289 is vertically long as a whole, and the upper half and the lower half in the figure individually form a trapezoid.

In the cross section of the impact resistant piece 289, the right side surface in the drawing corresponds to the contact surface 400 including the contact regions 401 and 402. Of abutment surface 400, the surface P ₁ including the contact region 401 located on the lower side in the drawing is at an angle α inclined to the plane X-Y perpendicular to the optical axis Z.

Further, of the abutment surface 400, the surface P ₂ containing the contact region 402 located on the upper side in the drawing, an angle β inclined to the plane X-Y perpendicular to the optical axis Z. Thus, the contact surface 400 of the shock resistant piece 289 includes a plurality of contact regions 401 and 402 formed in different directions.

  FIG. 13 is a view showing another cross section of the impact resistant piece 289. The plane R shown in FIG. 13 is orthogonal to the plane Q described above, and is also orthogonal to one contact region 401 on the side peripheral surface of the impact resistant piece 289. Further, the plane R is substantially orthogonal to the inner peripheral surface of the front tube 204. Here, “substantially orthogonal” means that since the inner peripheral surface of the front tube 204 is a cylindrical surface, it cannot be geometrically perpendicular to the plane R.

  FIG. 14 shows a cross-sectional shape of one contact region 401 of the impact-resistant piece 289 cut by the plane R. As shown in the figure, the contact region 401 has an inclination larger than the right angle by an angle δ with respect to the inner peripheral surface of the front tube 204.

  Thus, the contact area 401 has both the inclination shown in FIG. 12 and the inclination shown in FIG. Such an inclination of the contact area 401 is equal to the inclination of the cam surface of the shock resistant cam groove 299 to which the contact area 401 comes into contact.

  More specifically, when the front tube 204 is incorporated in the lens unit 200, the inclination of the impact-resistant piece 289 in the contact region 401 is the position indicated by the symbol B in FIG. It is equal to the inclination of the cam surface in the contact section on the wide angle end side of 299. As a result, the contact region 401 of the impact resistant piece 289 can be contacted by the surface with the contact portion of the cam surface of the impact resistant cam groove 299 to disperse the impact of the contact.

  Similarly, the other contact area 402 of the impact resistant piece 289 has the same inclination as the inclination of the cam surface in the contact section on the telephoto end side of the impact resistant cam groove 299. As a result, the contact region 402 of the shock resistant piece 289 can also contact the cam contact surface section of the shock resistant cam groove 299 with the surface to disperse the contact impact.

  With reference to FIG. 10 again, the impact resistant piece 289 and the impact resistant cam groove 299 will be described. When the lens unit 200 is assembled, the shock-resistant piece 289 having the above-described shape is formed in the direction of the optical axis Z from the opening 290 having the same cross-sectional shape as the shock-resistant cam groove 299 at the position indicated by the symbol F. It is inserted into the impact resistant cam groove 299. At the position of F, since the groove width of the shock-resistant cam groove 299 is wide, a vertically long shock-resistant piece 289 in the drawing can be passed.

  Subsequently, the impact-resistant cam groove 299 changes its direction by 90 ° and extends parallel to the plane XY. The groove width of the impact resistant cam groove 299 is narrowed at the position of symbol E, but since the lateral width of the impact resistant piece 289 in the drawing is also narrow, the impact resistant piece 289 can be inserted to the magnification changing section beyond the telephoto end. .

  An abutting section is provided adjacent to the telephoto end in the zooming section of the impact cam groove 299. In the contact section, the direction in which the cam surface of the impact resistant cam groove 299 extends forms an angle β with respect to the plane XY perpendicular to the optical axis Z. On the other hand, the contact region 402 in the shock-resistant piece 289 has an inclination of an angle β with respect to the plane XY, as already described.

  Further, the contact surface 400 of the impact resistant piece 289 has the same inclination as the inclination of the cam surface at the position indicated by the symbol E in the impact resistant cam groove 299. Therefore, when the shock-resistant piece 289 is positioned in the contact section on the telephoto end side of the shock-resistant cam groove 299, the cam surface and the contact area 402 are parallel.

  As a result, when an impact is applied from the direction of the optical axis Z to the tip of the front tube 204 in the lens unit 200, the impact resistant piece 289 comes into contact with the impact resistant cam groove 299 on the surface. Further, the contact surface between the impact resistant piece 289 and the impact resistant cam groove 299 forms an angle close to a right angle with respect to the optical axis Z direction to which the impact is applied, as can be seen from the cross-sectional shape at the position indicated by E. By these actions, the impact resistant piece 289 and the impact resistant cam groove 299 can withstand a large impact and maintain the engagement relationship between the leading tube 204 and the cam tube 205.

  Subsequently, when the shock-resistant piece 289 passes the contact section on the telephoto end side, the extending direction of the shock-resistant cam groove 299 forms a large angle with respect to the plane XY. However, as can be seen from the cross-sectional shapes at the positions indicated by reference signs D and C, the impact-resistant cam groove 299 has a wider groove width, so that the impact-resistant piece 289 can smoothly move inside the impact-resistant cam groove 299.

  As indicated by reference numeral C in the figure, when the impact resistant piece 289 is located in a section where the impact resistant cam groove 299 has a large inclination with respect to the plane XY, the impact received in the optical axis Z direction by the front tube 204. Acts on the cam cylinder 205 from the drive cam pin 281 through the drive cam groove 291. As a result, the cam cylinder 205 rotates and the drive cam pin 281 moves toward the wide-angle end of the drive cam groove 291.

  The impact received by these actions is mitigated, and the drive cam pin 281 and the drive cam groove 291 are prevented from being damaged. Therefore, in the shock-resistant cam groove 299, the shock-resistant piece 289 does not have to contact the shock-resistant cam groove 299 in a wide section between the pair of contact sections.

  Further, with the rotation of the cam cylinder 205 as described above, the shock resistant cam groove 299 moves to the abutting section of the shock resistant cam groove 299 on the wide angle end side. In the contact section on the wide-angle end side, the direction in which the cam surface of the shock resistant cam groove 299 extends forms an angle α with respect to the plane XY perpendicular to the optical axis Z. On the other hand, the contact area 401 in the impact-resistant piece 289 forms an angle α with respect to the plane XY, as already described.

  Further, the contact surface 400 of the impact resistant piece 289 has the same inclination as the inclination of the cam surface at the position indicated by the symbol B in the impact resistant cam groove 299. Therefore, when the shock-resistant piece 289 is positioned in the contact section on the wide-angle end side of the shock-resistant cam groove 299, the cam surface and the contact area 402 are parallel to each other.

  As a result, when an impact is applied from the optical axis Z direction to the front end of the front tube 204 in the lens unit 200, the impact resistant piece 289 comes into contact with the impact resistant cam groove 299 face to face. Further, the contact surface between the impact resistant piece 289 and the impact resistant cam groove 299 forms an angle close to a right angle with respect to the optical axis Z direction to which the impact is applied, as can be seen from the cross-sectional shape at the position indicated by E. By these actions, the impact resistant piece 289 and the impact resistant cam groove 299 can withstand a large impact and maintain the engagement relationship between the leading tube 204 and the cam tube 205 even in the abutting section at the wide angle end.

  Further, the pair of drive cam pins 281 are arranged with the impact resistant piece 289 interposed therebetween. In the lens unit 200, the pair of drive cam grooves 291 are arranged with the impact cam groove 299 interposed therebetween. As a result, the buffering function by the impact resistant piece 289 and the impact resistant cam groove 299 acts substantially equally on the pair of drive cam pins 281 and the pair of drive cam grooves 291.

  In the above example, the case where the shock-resistant piece 289 has moved to the contact section on the wide-angle end side due to the impact received by the front tube 204 has been described. However, even when the lens unit 200 is scaled to the wide-angle side and the impact-resistant piece 289 is positioned in the wide-angle side contact section from the beginning, the impact-resistant piece 289 and the impact-resistant cam groove 299 receive a large impact. be able to.

  When the cam cylinder 205 is further rotated and the shock-resistant piece 289 passes through the contact section on the wide-angle end side, the extending direction of the shock-resistant cam groove 299 makes a large angle again with respect to the plane XY. However, as can be seen from the cross-sectional shape of the position indicated by the symbol A, the impact-resistant cam groove 299 communicating with the retracted position has a wide groove width, so that the impact-resistant piece 289 can smoothly move inside the impact-resistant cam groove 299. .

  In the lens unit 200 having the impact cam groove 299 and the impact resistant piece 289 as described above, when an impact including a component in the optical axis Z direction is applied to the front tube 204, the impact is forward of the lens unit 200. Regardless of whether it is heading toward the rear of the lens unit 200, one of the pair of abutting sections 296 abuts against the impact-resistant piece 289 and receives the impact.

  In the above example, the shock-resistant piece 289 and the shock-resistant cam groove 299 are in contact with each other and receive the shock when receiving an impact in the optical axis Z direction of the lens unit 200 from the front end side of the lens unit 200. Have Further, in the lens unit 200, a contact surface 400 is also provided on the front side of the impact resistant piece 289 in the optical axis Z direction, and the impact from the rear end side to the front end side of the lens unit 200 is received by the impact resistant cam groove 299. May be added.

  In the above example, the contact sections are arranged at both ends of the drive section in the drive cam groove 291, but the contact sections may be provided in other sections. Furthermore, more contact sections may be provided. In the case of such a configuration, the shape of the shock-resistant piece 289 is also changed according to the number and shape of the provided contact sections.

  As described above, in the lens unit 200, the drive cam groove 291 and the drive cam pin 281 ensure the positioning accuracy of the front tube 204, and the impact resistant piece 289 and the impact resistant cam groove 299 receive the impact. Therefore, both high impact resistance and high-accuracy positioning and smooth driving can be achieved.

  Up to this point, the single-lens reflex camera 100 has been described as an example, but the above-described structure can also be applied to the lens unit 200 of a non-reflex camera. Furthermore, in addition to the camera in which the lens unit 200 and the camera body 300 are integrally formed, the above structure is also applied to a telescope, a surveying instrument, an outdoor microscope, etc. that are provided with an optical member driven by a cam and carried by the user it can.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Single-lens reflex camera, 200 Lens unit, 201 Fixed cylinder, 202 Operation ring, 203 Straight advance cylinder, 204 First cylinder, 205 Cam cylinder, 206 Guide cylinder, 207 First moving frame, 208 Lens side mount part, 209 , 210 First lens group, 212, 222, 232, 232, 242 Lens holding frame, 220 Second lens group, 230 Third lens group, 240 Fourth lens group, 270 Lead screw assembly, 272 Stepping motor, 274 Feed Screw, 276 frame, 278 rack member, 280 lead part, 281 drive cam pin, 282 rectilinear piece, 283, 284 cam pin, 285 connecting pin, 286 bayonet claw, 287 key, 288, 297 rectilinear groove, 289 impact resistant piece, 290 opening Part, 291 Drive cam groove, 292 Lead 293, 294 Lead groove, 295 Positioning unit, 299 Shock-resistant cam groove, 300 Camera body, 310 Shutter unit, 320 Substrate, 322 Control unit, 324 Image processing unit, 330 Image sensor, 332 Low-pass filter, 340 Display unit, 350 Finder, 352 focusing screen, 354 pentaprism, 356 finder optical system, 360 body side mount, 370 mirror unit, 371 main mirror, 372 main mirror holder, 373 main mirror rotation axis, 374 sub mirror, 375 sub mirror holder, 376 Sub-mirror rotation axis, 380 focusing optical system, 382 focus detection sensor, 390 photometric sensor, 400 contact surface, 401, 402 contact area

Claims (9)

A holding member that has one of a driving cam groove and a driving cam pin that engage with each other to transmit a driving force, and holds an optical member;
A drive member that has the other of the drive cam groove and the drive cam pin and moves the holding member in the optical axis direction when rotated around the optical axis of the optical member; and one of the holding member and the drive member Shock-resistant piece provided in
A cam that is formed on the other of the holding member and the driving member and engages with the impact-resistant piece, and includes a contact section that contacts the contact surface of the impact-resistant piece when the holding member receives an impact from the outside. An impact-resistant cam groove having a surface, and an angle formed by a surface on which the impact-resistant cam groove is provided on the other of the holding member and the drive member and a cam surface of the impact-resistant cam groove is A lens barrel that is larger in the contact section than sections other than the contact section.   2. The lens barrel according to claim 1, wherein the impact cam groove is spaced apart from the drive cam groove in the optical axis direction and is disposed at the same position as the drive cam groove in a circumferential direction around the optical axis. . The drive cam groove has a fine movement section in which an angle formed by an extending direction of the drive cam groove with respect to a surface orthogonal to the optical axis is smaller than other sections.
3. The lens according to claim 1, wherein when the drive cam pin is positioned in the fine movement section of the drive cam groove, the shock-resistant piece is positioned in the contact section of the shock-resistant cam groove. A lens barrel.   4. The lens barrel according to claim 3, wherein the fine movement section is arranged at an end portion of a zooming section in which the driving cam and the driving cam groove change a magnification of an optical system including the optical member.   The angle formed at the boundary between the cam surface of the shock-resistant cam groove and the other surface of the holding member and the drive member is formed with respect to a plane in which the extending direction of the drive cam groove is orthogonal to the optical axis. The lens barrel according to claim 1, wherein the lens barrel is smaller than the contact section when the drive cam pin is positioned in a section having a large inclination angle.   The contact surface of the impact-resistant piece is separated from the cam surface of the impact-resistant cam groove when neither the holding member nor the drive member is subjected to an impact. The lens barrel according to claim 1.   The lens barrel according to any one of claims 1 to 6, wherein the impact-resistant cam groove has a wider groove width than the contact section in a section other than the contact section. A pair of the drive cam grooves disposed across the shock-resistant cam groove in one of the holding member and the drive member;
8. The device according to claim 1, further comprising: a pair of drive cam pins disposed on the other side of the holding member and the drive member with the shock-resistant piece interposed therebetween and engaged with the pair of drive cam grooves. The lens barrel according to the item.   An imaging apparatus comprising the lens barrel according to any one of claims 1 to 8.

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