JP2011158608A - Lens barrel and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism capable of obtaining, without causing upsizing, a lens barrel in which engagement of a driving barrel with a moving cam barrel is hardly released even if external force acts thereon. <P>SOLUTION: The lens barrel includes: the moving cam barrel 19 which is movable in an optical axis direction while rotating, and with which a first group lens holder 10 is cam-engaged and the first group lens holder 10 is moved in the optical axis direction by the rotation; the driving barrel 30 which has a groove 31, in which a driving pin 28 provided on an outer periphery part of the moving cam barrel 19 is engaged in a periphery direction, on an inner periphery part and transmits the rotation to the moving cam barrel 19; driving means 44 and 45 which drive to rotate the driving barrel 30; and pressing means 37 and 40 which have a slider follower 39 pressing the driving barrel 30 inwardly in a radial direction toward an outer peripheral surface side of the moving cam barrel 19. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a zoom lens barrel mounted on, for example, a digital camera or the like and an imaging apparatus including the lens barrel.

  An example of a conventional zoom lens barrel is shown in FIG. 5 (Patent Document 1). In this lens barrel, a driving cylinder 902 is rotatably fitted on an outer peripheral part of a fixed cylinder 901. The driving cylinder 902 transmits a driving force from a driving mechanism (not shown) to a gear part 903 provided on the outer peripheral part. As a result, it is rotationally driven. In addition, three grooves 904 extending along the optical axis direction are formed in the inner circumferential portion of the drive cylinder 902 at substantially equal intervals in the circumferential direction.

  The cam cylinder 905 supports an optical group (not shown) arranged on the inner peripheral side so as to be movable in the optical axis direction according to the zoom operation, and drive pins 906 are arranged at substantially equal intervals in the circumferential direction on the outer peripheral portion. In three places. The optical group disposed on the inner peripheral side of the cam cylinder 905 is supported by the rectilinear cylinder 907 so as to be linearly movable in the optical axis direction.

  When the drive pin 906 of the cam barrel 905 engages with the groove 904 of the drive barrel 902, the cam barrel 905 rotates with the drive barrel 902, and the optical group moves forward and backward in the optical axis direction along the rectilinear barrel 907. To do.

Japanese Patent No. 4261648

  In the conventional lens barrel, when the operation of the optical group or the cam barrel 905 is hindered by an external force, a force resisting rotation acts on the drive barrel 902 via the drive pin 906 and the groove 904. At this time, since the driving force from the driving source is applied to the gear portion 903 of the driving cylinder 902, the driving cylinder 902 is locked at the portion of the gear section 903.

  Therefore, when the above-described external force is increased, the drive cylinder 902 is moved toward the fixed cylinder 901 in one direction where there is a backlash, and the drive pin 906 is deformed by the force pushing the groove 904, and this deformation causes the drive cylinder 902 to move. There is a possibility that the engagement between the pin 906 and the groove 904 is released.

  In order to prevent the engagement between the drive pin 906 and the groove 904 from being released, for example, it is conceivable to increase the length of the drive pin 906 by deepening the groove 904. The thickness of 902 is increased, which leads to an increase in the size of the lens barrel.

  Therefore, an object of the present invention is to provide a mechanism that can obtain a lens barrel that is difficult to disengage between the drive cylinder and the movable cam cylinder even when an external force is applied without causing an increase in size.

  In order to achieve the above object, the lens barrel of the present invention is a zoom type lens barrel that moves in the optical axis direction between the photographing position and the retracted position to change the photographing magnification, while rotating. A movable cam cylinder that is movable in the optical axis direction, the lens holder is cam-engaged and moves the lens holder in the optical axis direction by the rotation, and the movable cam cylinder is engaged in the circumferential direction with respect to the movable cam cylinder. A drive cylinder that transmits rotation to the movable cam cylinder; a drive means that rotationally drives the drive cylinder; and a pressing means that has a pressing portion that presses the drive cylinder radially toward the peripheral surface of the movable cam cylinder; It is characterized by providing.

  According to the present invention, it is possible to obtain a lens barrel in which the engagement between the drive cylinder and the movable cam cylinder is hardly released even when an external force is applied, without causing an increase in size.

It is a disassembled perspective view for demonstrating the lens-barrel which is an example of embodiment of this invention. (A) is a figure which shows the state by which the light emission part of strobe device is arrange | positioned in the accommodation position, (b) is a figure which shows the state in which the light emission part of strobe device is arrange | positioned in the use position which faced the to-be-photographed object. (A) is an external perspective view showing the retracted state of the lens barrel, (b) is an external perspective view showing the shooting state of the lens barrel. (A) is a cross-sectional view of the main part showing a state where the slider follower is cam-engaged with the parallel cam part of the cam groove, and (b) is a main part showing a state where the engagement between the slider follower and the parallel cam part is released. FIG. It is a disassembled perspective view for demonstrating the conventional lens barrel.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view for explaining a zoom lens barrel as an example of an embodiment of the present invention.

  As shown in FIG. 1, the optical system of the lens barrel of the present embodiment is composed of a first lens group 10a, a second lens group 11a, and a focus lens (not shown) that is a third lens group. Installed. The first group lens 10 a is held by the first group lens holder 10, and the second group lens 11 a is held by the second group lens holder 11.

  The rectilinear guide plate 12 engages with a groove (not shown) formed in the inner periphery of the first group lens holder 10 and extending in the optical axis direction, and supports the first group lens holder 10 so as to be movable in the optical axis direction. The first group guide rod 13 is extended along the optical axis direction.

  In addition, the linear guide plate 12 engages with a second group linear advance hole 14 provided on the outer peripheral portion of the second group lens holder 11 to support the second group lens holder 11 so as to be movable in the optical axis direction. A rod 15 extends along the optical axis direction.

  Further, a plurality of protrusions 16 are provided on the outer peripheral edge portion of the rectilinear guide plate 12, and a plurality of grooves 18 extending in the optical axis direction provided on the inner peripheral portion of the fixed cam cylinder 17. , The linear guide plate 12 is supported so as to be movable in the optical axis direction.

  Three cam followers 20 are provided on the outer peripheral portion on the rear end side of the movable cam cylinder 19 at substantially equal intervals in the circumferential direction. These cam followers 20 are provided on the inner peripheral part of the fixed cam cylinder 17. Each cam groove 21 is cam-engaged. As the moving cam cylinder 19 rotates, the cam follower 20 moves along the trajectory of the cam groove 21, whereby the moving cam cylinder 19 can be displaced in the optical axis direction while rotating.

  Further, a flange 22 is provided on the inner peripheral portion on the rear end side of the movable cam cylinder 19, and when the hook 23 of the rectilinear guide plate 12 is engaged with the flange 22, the rectilinear guide plate 12 is moved. The cam cylinder 19 is rotatably engaged. Thereby, along with the displacement of the movable cam cylinder 19 in the optical axis direction, the linear guide plate 12 can also be displaced in the optical axis direction.

  Three first group cam followers 24 are provided at substantially equal intervals in the circumferential direction on the outer peripheral portion of the first group lens holder 10, and these first group cam followers 24 are provided on the inner peripheral portion of the movable cam cylinder 19. The cams are respectively engaged with the three first-group cam grooves 25. The first group cam follower 24 moves along the locus of the first group cam groove 25 as the movable cam cylinder 19 rotates.

  Further, as described above, the first group lens holder 10 is supported by the first group guide rod 13 of the rectilinear guide plate 12 so as to be movable in the optical axis direction. The groove 25 is displaced according to the amount of displacement in the optical axis direction.

  On the outer peripheral portion of the second group lens holder 11, two second group cam followers 26 are provided at substantially equal intervals in the circumferential direction. These second group cam followers 26 are provided on the inner peripheral portion of the movable cam cylinder 19. Each of the cams engages with the second group cam groove 27 at three locations. The second group cam follower 26 moves along the locus of the second group cam groove 27 as the movable cam cylinder 19 rotates.

  Further, as described above, the second group lens holder 11 is supported by the second group guide rod 15 of the rectilinear guide plate 12 so as to be movable in the optical axis direction. The groove 27 is displaced according to the amount of displacement in the optical axis direction.

  Three drive pins 28 are provided in the outer peripheral portion on the rear end side of the movable cam cylinder 19 at substantially equal intervals in the circumferential direction, and these drive pins 28 are provided to penetrate the peripheral wall of the fixed cam cylinder 17. The cam hole 29 is inserted and protruded from the outer peripheral surface of the fixed cam cylinder 17.

  The locus of the cam groove 21 and the cam hole 29 of the fixed cam cylinder 17 has the same shape. When the movable cam cylinder 19 moves relative to the fixed cam cylinder 17 in the optical axis direction, the drive pin 28 Then, it moves along the locus of the cam hole 29 while maintaining the state of protruding from the cam hole 29.

  The drive cylinder 30 is fitted on the outer peripheral side of the fixed cam cylinder 17 and is rotatably supported. Three grooves 31 extending in the optical axis direction are arranged at substantially equal intervals in the circumferential direction on the inner peripheral portion of the drive cylinder 30, and the drive pin 28 of the movable cam cylinder 19 is engaged with each of these grooves 31. To do. Thereby, the rotation of the drive cylinder 30 driven by the drive source 44 is transmitted to the movable cam cylinder 19 via the groove 31 and the drive pin 28.

  The drive source 44 is, for example, an electromagnetic motor that converts electric power into motive power, and the motive power of the drive source 44 is transmitted via a gear train 45 to a gear portion 46 that is provided on the outer peripheral portion on the rear end side of the drive cylinder 30. As a result, the drive cylinder 30 is rotationally driven.

  The first group lens holder 10, the second group lens holder 11, the rectilinear guide plate 12, the fixed cam cylinder 17, the movable cam cylinder 19, and the drive cylinder 30 are integrated into the lens barrel base 32. The lens barrel of the present invention is configured by fixing the imaging element holder 33 holding the imaging element (not shown) and the barrel base 32 so as to sandwich the flange portion 17a of the fixed cam barrel 17.

  A strobe base 34 that holds a capacitor and a strobe substrate is attached to the side of the lens barrel base 32. The strobe base 34 holds a strobe shaft 35 extending in a direction perpendicular to the optical axis, and a strobe device 36 is rotatably supported on the strobe shaft 35.

  In FIG. 1, the strobe device 36 rotates in the closing direction (arrow A direction) so that the light emitting unit 36 a is disposed in the storage position, and the light emitting unit 36 a rotates in the opening direction (arrow B direction) so that the light emitting unit 36 a It is arranged at the use position facing

  Further, the lens barrel base 32 holds a slider shaft 38 extending along the optical axis direction, and the slider 37 is movable along the optical axis direction on the outer peripheral surface of the drive cylinder 30 on the slider shaft 38. Supported by

  The strobe device 36 is rotated by the movement of the slider 37 in the optical axis direction, and the light emitting unit 36a is disposed at the storage position or the use position. A slider follower 39 that can be engaged with a cam groove 41 provided on the outer peripheral surface of the drive cylinder 30 is fitted to the slider 37 so as to be movable in a direction perpendicular to the optical axis (the radial direction of the drive cylinder 30). . The slider follower 39 is biased radially inward by the compression spring 40. Here, the slider follower 39 corresponds to an example of a pressing portion of the present invention.

  Next, the rotation operation of the strobe device 36 by the movement of the slider 37 in the optical axis direction will be described with reference to FIG.

  FIG. 2A is a diagram showing a state in which the light emitting unit 36a of the strobe device 36 is disposed at the storage position, and FIG. 2B is a state in which the light emitting unit 36a of the strobe device 36 is disposed at the use position facing the subject. FIG.

  The strobe device 36 is stably supported at each position by a toggle spring (not shown) whose urging direction is switched between the storage position and the use position of the light emitting unit 36a.

  As shown in FIG. 2A, the slider 37 is provided with a U-shaped portion 42 that sandwiches a protrusion 43 protruding from the strobe device 36.

  2A, when the slider 37 moves to the right in the optical axis direction, the protrusion 43 is pressed by the U-shaped portion 42, and the strobe device 36 is centered on the strobe shaft 35. As shown in FIG.

  This rotational force lifts the strobe device 36 against the biasing force of the toggle spring and switches the biasing direction of the toggle spring, so that the strobe device 36 is rotated counterclockwise as shown in FIG. And the light emitting part 36a is arranged at the use position. When the strobe device 36 is rotated from the use position of the light emitting unit 36a to the storage position side, the reverse operation described above may be performed.

  FIG. 3 is an external perspective view of the lens barrel described in FIGS. 1 and 2. FIG. 3A is an external perspective view showing the retracted state of the lens barrel, and FIG. 3B is an external perspective view showing the photographing state of the lens barrel.

  The lens barrel of the present embodiment is a zoom type lens barrel that moves in the optical axis direction between an imaging position and a retracted position to change the imaging magnification. The positions of the 10 and second group lens holders 11 in the optical axis direction are determined.

  Next, returning to FIG. 1, the cam groove 41 provided on the outer peripheral surface of the drive cylinder 30 will be described.

  In the cam groove 41, a feeding cam portion 41a in which the position in the optical axis direction of the engaging portion of the slider follower 39 is changed by rotation of the drive cylinder 30, and parallel cam portions 41b and 41c in which the position in the optical axis direction is not changed are arranged. The

  The slider follower 39 is engaged with the parallel cam portion 41c in the rotational phase of the drive cylinder 30 when the lens barrel is in the retracted state, and is parallel cam in the rotational phase of the drive cylinder 30 when the lens barrel is in the photographing state. Engage with the part 41b.

  Further, when the lens barrel is switched from the retracted state to the photographing state, the slider 37 is displaced in the optical axis direction by engaging the slider follower 39 with the feeding cam portion 41a. Accordingly, the strobe device 36 rotates between the storage position and the use position of the light emitting unit 36a in accordance with the change between the retracted state and the photographing state of the lens barrel.

  The strobe device 36 is usually rotated according to the lens barrel storage state and photographing state according to a user instruction on the camera body, and the light emitting unit 36a is disposed at the storage position or the use position. You may rotate and arrange | position the light emission part 36a in a storage position or a use position.

  FIG. 4 is a cross-sectional view of the main part showing the relationship between the slider follower 39 and the parallel cam portion 41 c of the cam groove 41. FIG. 4A shows a state in which the slider follower 39 is cam-engaged with the parallel cam portion 41 c of the cam groove 41.

  In the retracted state of the lens barrel, when the strobe device 36 in which the light emitting portion 36a is in the retracted position is manually rotated, the U-shaped portion 42 of the slider 37 is pressed by the projection 43 of the strobe device 36, and the slider follower 39 is parallel. The force which pushes the cam part 41c to an optical axis direction works.

  Further, the slider follower 39 is separated from the parallel cam portion 41 c by being pushed into the slider 37 against the urging force of the compression spring 40 by the slope of the cam section of the parallel cam portion 41 c, and is parallel to the slider follower 39. Cam engagement with the cam portion 41c is released. FIG. 4B shows a state in which the engagement between the slider follower 39 and the parallel cam portion 41c is released. In this state, the strobe device 36 has the light emitting portion 36a disposed at the use position.

  Similarly, in the shooting state of the lens barrel, when the strobe device 36 in which the light emitting unit 36a is in the use position is manually rotated, the U-shaped portion 42 of the slider 37 is pressed by the projection 43 of the strobe device 36, and the slider follower The force 39 presses the parallel cam portion 41b in the optical axis direction.

  Further, the slider follower 39 is separated from the parallel cam portion 41b by being pushed into the slider 37 against the urging force of the compression spring 40 by the slope of the cam section of the parallel cam portion 41b, and the slider follower 39 and the parallel cam 39 are parallel cams. The engagement with the portion 41b is released. In this state, in the strobe device 36, the light emitting unit 36a is disposed at the storage position.

  In this manner, by manually rotating the strobe device 36, the light emitting unit 36a can be disposed at the use position when the camera is turned on. Further, when the strobe light emission is not desired, the user can rotate the strobe device 36 to place the light emitting unit 36a in the storage position.

  The slider follower 39 may be a movable shaft, and when an external force is applied to the strobe device 36, it may be moved away from the parallel cam portions 41a and 41b by a driving means (not shown).

  By the way, as described above, the lens barrel advances and retracts the first group lens holder 10 in the optical axis direction via the movable cam barrel 19 by the rotation of the drive barrel 30. This also means that when an external force is applied to the first group lens holder 10 in the optical axis direction, the force reaches the drive cylinder 30. As an external force here, the camera body was put in a camera case (leather case, etc.), the power was accidentally turned on and the lens barrel started to be extended, and the lens barrel was stuck in the case. An external force applied to the first group lens holder 10 by entering the state can be exemplified. In other cases, such as when the user presses the tip of the lens barrel with a finger or the like when the power is on or during shooting, or when the camera body is placed on a desk or the like with the lens barrel facing down An example is an external force applied to the first lens group holder 10 when the power is turned on in a state.

  Here, since the rotational force from the drive source 44 is acting on the drive cylinder 30 through the gear train 45 meshing with the gear portion 46, the external force causes the drive cylinder 30 to move in the direction opposite to the rotational force. When applied in the direction of rotation, a force for deforming the drive cylinder 30 works.

  More specifically, although the deformation of the drive cylinder 30 is suppressed at the meshing part of the gear part 46 and the gear train 45, the engagement part between the groove 31 extending in the optical axis direction and the drive pin 28 of the movable cam cylinder 19 is suppressed. A pressing force is generated on the side surface of the groove 31.

  This pressing force acts as a force that deforms the drive cylinder 30 outward in the radial direction. In the present embodiment, the engaging portions between the groove 31 and the drive pin 28 are arranged at three substantially equal intervals in the circumferential direction. Therefore, the drive cylinder 30 is to be deformed into a substantially triangular shape. Therefore, when the deformation becomes large, the engagement allowance between the groove 31 and the drive pin 28 is reduced, and the engagement between the drive pin 28 and the groove 31 is released, and the lens barrel may become inoperable.

  Here, in the present embodiment, the slider follower 39 always presses the outer peripheral surface of the drive cylinder 30 radially inward by the urging force of the compression spring 40. The pressing force inward in the radial direction by the slider follower 39 presses the drive cylinder 30 against the fixed cam cylinder 17 side to bring the fitting back to one side, and the groove 31 and the drive pin 28 engage with the groove 31. It acts to reduce the pressing force generated on the side surface of the. Thereby, it can suppress that the drive cylinder 30 deform | transforms to radial direction outward.

  As described above, in the present embodiment, even when an external force is applied to the first group lens holder 10 in the optical axis direction, the external force suppresses the drive cylinder 30 from being deformed radially outward. it can. As a result, it is possible to obtain a lens barrel in which the engagement margin between the drive pin 28 and the groove 31 can be sufficiently secured, and the engagement between the drive pin 28 and the groove 31 is difficult to be released without causing an increase in size. Can do.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 1st group lens holder 19 Moving cam cylinder 28 Drive pin 30 Drive cylinder 31 Groove 36a Light emission part 36 Strobe device 39 Slider follower 40 Compression spring 44 Drive source

Claims (8)

A zoom type lens barrel that moves in the optical axis direction between the shooting position and the retracted position to change the shooting magnification,
A movable cam cylinder that is movable in the optical axis direction while being rotated, and the lens holder is cam-engaged to move the lens holder in the optical axis direction by the rotation;
A driving cylinder that engages in the circumferential direction with respect to the movable cam cylinder and transmits rotation to the movable cam cylinder; and a driving means that rotationally drives the driving cylinder;
A lens barrel comprising: a pressing unit having a pressing portion that presses the driving cylinder in a radial direction toward the peripheral surface of the movable cam cylinder.   The lens barrel according to claim 1, wherein the drive cylinder is engaged in the circumferential direction at a plurality of positions in the circumferential direction with respect to the movable cam cylinder.   The lens barrel according to claim 1, wherein the drive cylinder is disposed on an outer peripheral side of the movable cam cylinder.   The drive cam is provided on an outer peripheral portion of the movable cam cylinder, and a groove for engaging the drive pin in the circumferential direction is provided on an inner peripheral portion of the drive cylinder along the optical axis direction. 3. The lens barrel according to 3.   5. The lens barrel according to claim 1, wherein the pressing portion is displaced in an optical axis direction with the rotation of the drive cylinder.   The lens barrel according to claim 5, further comprising a strobe device in which a direction of the light emitting unit is displaced between a storage position and a use position in accordance with the displacement of the pressing unit in the optical axis direction.   The lens according to claim 6, wherein the light emitting unit of the strobe device is disposed at the retracted position at the retracted position, and the light emitting unit of the strobe device is disposed at the use position at the photographing position. A lens barrel. An imaging apparatus having a zoom type lens barrel that moves in the optical axis direction between an imaging position and a retracted position to change an imaging magnification,
An imaging apparatus comprising the lens barrel according to any one of claims 1 to 7 as the lens barrel.