JP2006106588A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the miniaturization of a plate cam in a lens barrel in which a lens is moved by using the plate cam. <P>SOLUTION: When the plate cam 8 is rotated centering around a rotary shaft 8d as shown by (a), a rear group moving ring 3 and a rear group moving member 6 are moved while the front side cam roller 6a of the rear group moving member 6 is biased by a cam surface 8a for the front side cam roller. When the plate cam 8 is rotated to a certain angle at the time of changing the cam rollers as shown by (b), the front side cam roller 6a is in a state where it does not come into contact with the cam surface 8a for the front side cam roller, and continuously a rear side cam roller 6b is in a state where it comes into contact with a cam surface 8b for the rear side cam roller, whereby the changing operation of the cam rollers is completed. Furthermore, when the plate cam 8 is rotated as shown by (c), a lens is set to a wide angle state. When the plate cam 8 is rotated further as shown by (d), the rear group moving ring 3 and the rear group moving member 6 are moved so that the rear side cam roller 6b may be in a biased state by the cam surface 8b for the rear side cam roller, and the lens is set to a telephoto state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel having a cam member that is used in an imaging apparatus such as a digital camera or a video camera.

  In a lens barrel of an imaging device such as a digital camera, it is necessary to move the lens in the optical axis direction for the retracting motion for the storing operation of the lens moving unit in the imaging device body or the zooming operation of the lens. is there. One method for moving the lens is to use a plate cam.

  A lens barrel using a plate cam has a bar / sleeve structure in which a guide bar passes through a hole portion of a sleeve of a moving ring that holds a lens in a direction parallel to the optical axis of the lens. By this guide bar, the movement of the moving ring is limited in the longitudinal direction of the optical axis.

  In addition, the rod-shaped cam roller, which is a moving member fixed to the moving ring, is shifted to the cam surface of the plate cam, and the plate cam rotates and moves with respect to the fixed barrel so that the position of the cam roller is the plate. Move along the cam surface of the cam. Accordingly, the moving ring integrated with the cam roller moves in the longitudinal direction of the optical axis, and the position of the lens changes. The lens position is controlled by rotating and moving the plate cam in accordance with the cam surface shape.

  In the lens barrel that moves the lens by such rotation and movement of the plate cam, conventionally, as shown in Patent Document 1, only one cam roller is arranged in one lens moving part, There is also only one cam surface of the plate cam that engages the cam roller. Therefore, the cam roller for moving the lens and the cam surface engaged therewith are limited to one combination.

JP 2003-5010 A

  Thus, in order to move the lens by rotating and moving the plate cam, a cam surface corresponding to the movement of the lens must be arranged. Therefore, if the distance that the lens moves during the retraction or zooming operation is long, a long cam surface corresponding to the distance is required. And the higher the magnification of the lens, the longer the distance that the lens moves.

  However, in order to arrange such a long cam surface in the plate cam, a large space is required, and in order to move a plurality of lens moving parts with one plate cam, a plurality of cam surfaces are provided in the plate cam. Must be placed. Therefore, a larger space is required in the plate cam, and the plate cam becomes larger and larger.

  Digital cameras and video cameras in recent years are required to be compact, and therefore, it is desired to reduce the size of the lens barrel incorporated in the camera. However, due to the factors described above, in the conventional configuration, the plate cam for moving the lens becomes large, and the lens barrel becomes large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a compact lens barrel that can solve the above-described problems and can switch the combination of engagement between a cam and a cam roller.

  Technical features of the lens barrel according to the present invention for achieving the above-described object include a fixed barrel, a cam member rotatably provided on the fixed barrel side and having a plurality of cam surfaces, and the plurality of cam surfaces. A plurality of cam rollers that engage with the lens, and the cam member includes a lens moving ring that moves in the optical axis direction with respect to the fixed barrel as the cam member rotates, and the plurality of cam rollers are engaged with the plurality of cam surfaces. The combination to be combined is to be switched as the cam member rotates.

  The technical features of the lens barrel according to the present invention include a fixed barrel, a cam member that is rotatably provided on the fixed barrel side and has a first cam surface and a second cam surface, and the first A first cam roller that engages with the cam surface and a second cam roller that engages with the second cam surface, and moves in the optical axis direction with respect to the fixed barrel as the cam member rotates. A lens moving ring, the first cam roller is engaged with the first cam surface until the lens moving ring reaches a predetermined position, and after the lens moving ring reaches the predetermined position The second cam roller is engaged with the second cam surface.

  According to the lens barrel of the present invention, the lens moving ring can be easily moved in cooperation with the cam roller using a small cam member.

The present invention will be described in detail based on the illustrated embodiments.
1 is an exploded perspective view of the lens barrel of the embodiment, FIG. 2 is a perspective view of an assembled state, and in the X direction of the optical axis of the fixed barrel 1, a front group moving ring 2, a rear group moving ring 3, The main body barrel 4 is arranged, and the plate cam inner cover 5, the rear group moving member 6, the front group moving member 7, the plate cam 8 in the Y direction orthogonal to the X direction from the front group moving ring 2 and the rear group moving ring 3. The plate cam outer cover 9 is arranged.

  The front group moving ring 2 and the rear group moving ring 3 are fitted to the fixed barrel 1 so as to be movable in the longitudinal direction of the optical axis. Guide bars 11a and 11b having compression springs 10a and 10b attached thereto are inserted through holes 2b provided in the sleeve 2a of the front group moving ring 2 and holes 3b provided in the sleeve 3a of the rear group moving ring 3, respectively. Both ends of the guide bars 11 a and 11 b are fixed to the fixed barrel 1 and the main body barrel 4. The rear group moving member 6 is fixed to the side surface of the sleeve 3a in the Y direction, and the front group moving member 7 is fixed to the side surface of the sleeve 2a by the screw 12 through the hole 5a of the plate cam inner cover 5, respectively. Yes.

  A plate cam inner cover 5 is fixed to the fixed barrel 1, and a plate cam outer cover 9 is sandwiched between the rear group moving member 6, the front group moving member 7 and the plate cam 8. It is fixed.

  3A and 3B are perspective views of the plate cam 8 viewed from different directions. The plate cam 8 has a thickness in the axial direction of the rotary shaft 8d, and the cam rollers 6a and 6b of the rear group moving member 6 are shown. The front group cam surface 8c that engages with the cam roller 7a of the front group moving member 7 is provided with a step with respect to the front cam roller cam surface 8a and the rear cam roller cam surface 8b that are engaged with each other.

  The front group moving ring 2 is biased by the spring 10a through the sleeve 2a to the fixed lens barrel 1 side in the front direction of the optical axis, and the front group moving member 7 is also shifted to the front direction of the optical axis. 7 cam rollers 7 a are in contact with the front group cam surface 8 c of the plate cam 8.

  Similarly, the rear group moving ring 3 is offset by the spring 10b via the sleeve 3a in the forward direction of the optical axis, and the rear group moving member 6 is also offset in the forward direction of the optical axis. FIG. 4 is a perspective view of the rear group moving member 6, and cam rollers 6a and 6b are formed at a distance in the optical axis direction. As shown in FIG. 5, either the front cam roller 6a is in contact with the front cam roller cam surface 8a of the plate cam 8, or the rear cam roller 6b is in contact with the rear cam roller cam surface 8b.

  Which of the front cam roller 6 a and the rear cam roller 6 b of the rear group moving member 6 contacts the cam surfaces 8 a and 8 b of the plate cam 8 depends on the cam phase of the rotation of the plate cam 8. The rotating shaft 8 d of the plate cam 8 is inserted into the hole 9 a of the plate cam outer cover 9 and is held by screws 13 and washers 14.

  With such a configuration, when the plate cam 8 rotates about the rotation shaft 8d by a driving source (not shown) such as a motor, the positions of the front group moving ring 2 and the rear group moving ring 3 are changed or controlled. It will receive power and will remain stationary.

  6 shows a cut surface passing through the optical axis of the lens. The front group lens 21 is held by the front group moving ring 2, the rear group lens 22 is held by the rear group moving ring 3, and the front group moving ring 2 and the rear group The movable ring 3 is held by the fixed barrel 1 so as to be movable in the longitudinal direction of the optical axis.

  FIG. 7 is an explanatory view of the lens barrel when the lens is moved, and shows combinations of cam rollers and cam surfaces of the plate cam 8 respectively used by the front group moving member 7 and the rear group moving member 6 in each state. ing. In the retracted state in which the taking lenses 21 and 22 are retracted, the front group moving ring 2 is held by the cam roller 7a of the front group moving member 7 engaging the front group cam surface 8c, and the rear group moving member 6 is held by the front cam roller. 6a is held by engaging the front cam roller cam surface 8a of the plate cam 8.

  When the plate cam 8 rotates to a certain angle and the cam phase starts to change, the rear group moving member 6 is engaged with the front cam roller 6a and the front cam roller cam surface 8a, and the rear cam roller 6b and rear The cam surface 8b for the side cam roller is also engaged, and the cam roller is transferred. At this time, the front group moving ring 2 is continuously held by the cam roller 7a and the front group cam surface 8c being engaged.

  When the plate cam 8 further rotates from this state, the front cam roller 6a of the rear group moving member 6 is separated from the front cam roller cam surface 8a and is held only by the engagement between the rear cam roller 6b and the rear cam roller cam surface 8b. Become like that. In this state, when the plate cam 8 is further rotated to a certain angle, the lens is in a wide angle state. At this time, the front group moving member 7 is held by the engagement between the cam roller 7a and the front group cam surface 8c, and the rear group moving member 6 is held by the engagement between the rear cam roller 6b and the rear cam roller cam surface 8b. Has been.

  Further, when the plate cam 8 is rotated to a certain angle, the lens is in the telephoto state. At this time, the front group moving member 7 is held by engagement between the cam roller 7a and the front group cam surface 8c, and the rear group moving member 6 is held by engagement between the rear cam roller 6b and the rear cam roller cam surface 8b. ing.

  The cam roller transfer operation is continuously performed in a certain section of the rotation of the plate cam 8, and even if the processing accuracy of the plate cam 8 and the cam roller 7a and the rotation operation of the plate cam 8 are disturbed, the front cam roller 6a and the front cam roller are moved. The plate cam 8 does not rotate without moving from the combination of the cam surface 8a to the combination of the rear cam roller 6b and the rear cam roller cam surface 8b.

  FIG. 8 is a side view of the lens barrel when the lens is moved, and a part of the plate cam 8 is omitted so that the internal structure of the plate cam 8 can be seen. In the retracted state shown in (a), the front group moving ring 2 and the rear group moving ring 3 are housed inside the fixed barrel 1. At this time, the position of the rear group moving ring 3 is determined by the front cam roller 6a contacting the cam surface 8a for the front cam roller. Further, the rear cam roller 6b is not in contact with the front cam roller cam surface 8a and the rear cam roller cam surface 8b.

  Then, when the plate cam 8 is driven to perform a rotational movement about the rotation axis 8d perpendicular to the optical axis, the rear group moving ring 3 and the rear group moving member 6 are restricted by the guide bar 11b in the optical axis direction. The front cam roller 6a is biased by the spring 10b and moves while being biased to the front cam roller cam surface 8a.

  At the time of transfer shown in (b), when the plate cam 8 rotates to a certain angle, while the front cam roller 6a contacts the front cam roller cam surface 8a, the rear cam roller 6b also contacts the rear cam roller cam surface 8b, The transfer operation of the cam roller is performed. When the plate cam 8 further rotates, the front cam roller 6a is not in contact with the front cam roller cam surface 8a, and the rear cam roller 6b is continuously in contact with the rear cam roller cam surface 8b. The transfer operation is completed.

  At this time, the rear group moving ring 3 and the rear group moving member 6 are urged by the spring 10b, and the rear cam roller 6b is set at a position where it is shifted to the rear cam roller cam surface 8b. Further, as shown in (c), when the plate cam 8 is rotated, the lens is in a wide angle state.

  Thereafter, when the plate cam 8 further rotates as shown in (d), the rear group moving ring 3 and the rear group moving member 6 are in a state in which the rear cam roller 6b is shifted to the rear cam roller cam surface 8b. And the lens is in the telephoto state.

  Thus, since the transfer operation of the cam roller 7a of the front group moving member 7 is performed when the lens barrel is retracted, even if the projection image is disturbed due to rattling of the rear group moving ring 3 based on the transfer operation of the cam roller 7a, There is no effect when shooting.

  Further, the movement of the front group moving ring 2 from the retracted state (a) to the wide-angle state (c) and the telephoto state (d) is restricted by the guide bar 11a in the optical axis direction and is urged by the spring 10a. The cam roller 7a moves while being biased to the front group cam surface 8c. Contrary to these moving directions, the transition from the telephoto state of (d) to the wide-angle state of (c) and the retracted state of (a) is performed in the reverse order of each operation.

  FIG. 9 shows the movement of the movable rings 2 and 3 when an impact is applied from the front surface of the lens barrel. As shown in FIG. 9A, the plate cam 8 rotates to a certain angle, and the front group movable ring 2 is fixed to the fixed mirror. If an impact is applied to the front group moving ring 2 in the direction of the arrow due to a camera drop or the like in a state where it protrudes forward of the optical axis from the cylinder 1, the front group moving ring 2 is connected to the spring 10a and the rear group. The moving ring 3 is urged and held from the rear side of the optical axis by a spring 10b, and either the front cam roller cam surface 8a or the rear cam roller cam surface 8b, or both, and the front group cam surface 8c are respectively attached to the moving ring 3. The cam roller 7a is offset.

  Therefore, when an impact is applied, the moving rings 2 and 3 can move in the rearward direction of the optical axis while antagonizing the tension of the springs 10a and 10b to be biased and held as shown in FIG. The impact applied to the front group moving ring 2 can be reduced. Each moving ring 2 and 3 can be retracted to the retracted position, but if the applied impact cannot be alleviated even if it is moved to that position, the fixed barrel 1 and the main body barrel 4 cause further impact. Will receive.

  Accordingly, the cam surfaces 8a and 8b are not scratched or dented by the cam roller 7a or the like, and subsequent malfunctions can be prevented. At this time, the front cam roller 6a, the rear cam roller 6b, the cam roller 7a, the front cam roller cam surface 8a, the rear cam roller cam surface 8b, and the front group cam surface 8c are stepped and distanced in the optical axis direction and the optical axis vertical direction. Is arranged. Therefore, as shown in the front view of (c), the moving members 7, 6 and the cam roller 7a can move to the retracted position without interfering with each other when the moving rings 2, 3 are retracted.

  In the above-described embodiment, the transfer operation of the cam roller 7a of the front group moving member 7 is performed in the rear group moving ring 3, but in the embodiment, in the front group moving ring 2 instead of the rear group moving ring 3, or The present invention can be applied to both the front group moving ring 2 and the rear group moving ring 3. Further, there may be three or more optical cams in the plate cam 8 that determine the amount of movement of the optical lens during zooming and focusing operations.

  Furthermore, when a plurality of cam surfaces for a plurality of lens moving portions are arranged in the plate cam 8 with a step in the thickness direction, the plurality of lens moving portions can be moved simultaneously by one plate cam 8. Here, even when an impact is applied to the front group moving ring 2 as described above, the cam rollers and the cam surface are arranged with steps so that they move without interfering with each other even when the moving ring is retracted. be able to.

It is a disassembled perspective view of a lens barrel. It is a perspective view of an assembly state. It is a perspective view of a plate cam. It is a perspective view of a rear group moving member. It is a principal part perspective view of the lens-barrel which has a plate cam. It is sectional drawing of the lens-barrel along an optical axis direction. It is explanatory drawing of the combination of the cam roller in each state of a lens-barrel and a cam surface. It is a side view at the time of lens movement. It is explanatory drawing of a movement of a moving ring when a lens-barrel receives the impact from the front side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed barrel 2 Front group moving ring 3 Rear group moving ring 4 Main body barrel 5 Plate cam inner cover 6 Rear group moving member 6a Front cam roller 6b Rear cam roller 7 Front group moving member 7a Cam roller 8 Plate cam 8a Front cam roller cam Surface 8b Rear cam roller cam surface 8c Front group cam surface 8d Rotating shaft 9 Plate cam outer cover 10a, 10b Spring 11a, 11b Guide bar

Claims (10)

  A fixed lens barrel; a cam member rotatably provided on the fixed lens barrel side; a cam member having a plurality of cam surfaces; and a plurality of cam rollers engaging with the plurality of cam surfaces; A lens moving ring that moves in the optical axis direction with respect to the lens barrel, and a combination in which the plurality of cam rollers engage with the plurality of cam surfaces is switched as the cam member rotates. A lens barrel.   The lens barrel according to claim 1, wherein a combination in which the plurality of cam rollers are engaged with the plurality of cam surfaces is switched by a cam phase by rotation of the cam member.   A fixed barrel; a cam member rotatably provided on the fixed barrel side; having a first cam surface and a second cam surface; a first cam roller engaging with the first cam surface; And a lens moving ring that moves in the optical axis direction with respect to the fixed barrel as the cam member rotates, and the lens moving ring has a predetermined position. Until the first cam surface is engaged with the first cam roller, and after the lens moving ring reaches the predetermined position, the second cam roller is engaged with the second cam surface. A lens barrel characterized by that.   When the lens moving ring is at the predetermined position, the first cam roller is engaged with the first cam surface, and the second cam roller is engaged with the second cam surface. The lens barrel according to claim 3.   4. The lens barrel according to claim 1, wherein the lens moving ring is biased to one side in the optical axis direction.   The lens barrel according to claim 1, wherein the cam member is a plate cam.   The lens barrel according to claim 1, wherein the cam member is an optical cam.   The lens barrel according to claim 7, wherein two optical cams are arranged with a step in the plate thickness direction of the cam member to prevent interference between the cam members.   4. The lens barrel according to claim 1, wherein a combination of the cam member and the cam roller is switched in a retracted region.   An optical apparatus comprising the lens barrel according to any one of claims 1 to 9.

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