JP5985019B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel, and more specifically, a lens mirror provided with a focusing mechanism capable of performing an automatic focusing operation and a manual focusing operation without mechanical switching between an automatic focusing mechanism and a manual focusing mechanism. It relates to a cylinder.

  2. Description of the Related Art Conventionally, in a lens barrel applied to a photographing apparatus (camera) or the like that performs photography, an automatic focusing (autofocus; hereinafter referred to as AF) mechanism and a manual focusing (manual focus; hereinafter referred to as MF) mechanism are provided. In general, those which are configured to be used by switching between AF operation and MF operation as appropriate by switching mechanically have been put into practical use.

  In a conventional focusing mechanism in a lens barrel, for example, an AF operation is performed using a lead screw provided on a drive shaft of a drive motor, and a clutch mechanism is provided in a drive force transmission mechanism that transmits a drive force from the drive motor. During the MF operation, some clutch mechanisms are configured to block the transmission of the driving force from the drive motor and perform the MF operation with the driving force from the manual operation member.

  Further, in a lens barrel that performs an AF operation using an ultrasonic motor, a so-called full-time AF / MF mechanism configured such that an AF operation and an MF operation can be performed without switching by a motor and a differential mechanism. Various proposals have been made, for example, in JP-A-1-167715, etc., and are generally put into practical use.

  By the way, in an imaging device (camera), a so-called digital camera or the like that acquires an electronic image using an image sensor is widely used. In a lens barrel applied to this type of camera or the like, the rotation axis of the stepping motor is used as a lead screw and screwed into the lead screw in order to realize noise reduction by supporting imager AF operation and movie shooting. A focusing mechanism is often used that moves the nut in the optical axis direction to move the focusing lens (focusing lens) forward and backward in the optical axis direction.

JP-A-1-167715

  However, since the means disclosed in the above Japanese Patent Laid-Open No. 1-167715 is suitable for a drive mechanism using an ultrasonic motor, a focusing mechanism for moving the focusing lens back and forth using a lead screw, a nut or the like. Cannot be applied to.

  In a conventional lens barrel having a focusing mechanism using lead screws and nuts, an example of realizing a full-time AF / MF mechanism has not been found yet.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a simple lens barrel having a focusing mechanism that uses a lead screw to advance and retract the focusing lens in the optical axis direction. It is an object of the present invention to provide a lens barrel having a focusing mechanism that can execute an automatic focusing operation and a manual focusing operation at any time without mechanical switching operation with a simple configuration.

In order to achieve the above object, a lens barrel according to an aspect of the present invention includes a drive source, a lead screw that is provided in parallel with the optical axis and that is rotated by a rotational output of the drive source, and a first lens barrel. Frame means, a guide shaft that linearly guides the first frame means parallel to the optical axis, a spur gear portion on the outer peripheral surface, and a screw that engages with the lead screw. Along with the rotation, when the lead screw rotates, the nut member movable in parallel with the optical axis together with the first frame means and the spur gear portion of the nut member can rotate around the optical axis. The nut member is not rotated, the nut member can be moved in the optical axis direction, and the nut member is rotated and moved in the direction of the optical axis when rotated around the optical axis in response to a manual operation. With toothed gear And second frame means, and biasing member to maintain always abutted against the said nut member and said first frame means, and said second frame means is provided between the nut member Clutch means.
According to another aspect of the present invention, there is provided a lens barrel including: a driving source; a lead screw provided in parallel with an optical axis; and rotated by a rotational output of the driving source; first frame means; a guide shaft for the first frame means in parallel to the rectilinear guide and the optical axis, a nut screwed with the lead screw have a female thread on the outer peripheral surface has a center hole to fit the shank of the nut and an outer peripheral gear having spur gears, no to integrally with the nut and the outer peripheral gear, and the relative times nut assembly comprising a spring for pressing to the optical axis direction as you movement, the nut part assembly Rights Engage with gears and rotate around the optical axis.When the lead screw rotates, the nut assembly is non-rotated and the nut assembly can be moved in the optical axis direction. When rotating the nut part assembly, rotate the nut part assembly. The comprises a second frame means having internal gear to move in the direction of the optical axis, and the biasing member to maintain always abutted against the said nut assembly and said first frame means, .

  According to the present invention, in a lens barrel having a focusing mechanism that uses a lead screw to move a focusing lens back and forth in the optical axis direction, mechanical switching between automatic focusing operation and manual focusing operation with a simple configuration is possible. It is possible to provide a lens barrel having a focusing mechanism that can be executed at any time without operation.

1 is an external perspective view showing an overall image of the lens barrel of the first embodiment of the present invention, FIG. FIG. 1 is a plan view of the lens barrel in FIG. FIG. 2 is an exploded perspective view of a main part mainly showing an exterior part extracted from the constituent members of the lens barrel in FIG. 1; FIG. 2 is an exploded perspective view of a main part mainly showing a plurality of lens frames taken out from the constituent members of the lens barrel in FIG. FIG. 3 is an exploded perspective view of a main part mainly showing a fixing frame and a focusing mechanism out of the constituent members of the lens barrel in FIG. 1; FIG. 1 is an overall cross-sectional view showing a focusing mechanism in the lens barrel of FIG. Sectional drawing which follows the [7]-[7] line of FIG. Sectional drawing which follows the [8]-[8] line of FIG. Sectional drawing which follows the [9]-[9] line of FIG. FIG. 1 is a plan view of the lens barrel shown in FIG. The top view seen from the arrow [11] direction of FIG. The top view seen from the arrow [12] direction of FIG. The top view seen from the arrow [13] direction of FIG. The principal part expansion disassembled perspective view which takes out and shows the structural member relevant to the focusing mechanism in the lens barrel of the 2nd Embodiment of this invention, It is sectional drawing of the state which assembled only the structural member relevant to the focusing mechanism of FIG. 14, Comprising: Sectional drawing which follows the [15]-[15] line of FIG. The top view seen from the arrow [16] direction of FIG. The principal part expansion disassembled perspective view which takes out the structural member relevant to the focusing mechanism in the lens barrel of the 3rd Embodiment of this invention, and an exterior component, and shows it, FIG. 18 is a cross-sectional view of a state in which components and exterior parts related to the focusing mechanism of FIG. 17 are assembled, and a cross-sectional view taken along line [18]-[18] in FIG. Sectional drawing which follows the [19]-[19] line of FIG.

  The present invention will be described below with reference to the illustrated embodiments.

[First Embodiment]
A first embodiment of the present invention is applied to a camera or the like (hereinafter simply referred to as a camera) that is a photographing apparatus that performs photography and the like, and includes a lens barrel that includes a photographing optical system for forming a subject image. It is shown as an example.

  In each drawing used for the following description, each component may be shown with a different scale in order to make each component large enough to be recognized on the drawing. Therefore, according to the present invention, the number of constituent elements, the shape of the constituent elements, the ratio of the constituent element sizes, and the relative positional relationship of the constituent elements described in these drawings are limited to the illustrated embodiments. It is not a thing.

  FIGS. 1-13 is a figure which shows the lens barrel of the 1st Embodiment of this invention. Among these, FIG. 1 is an external perspective view showing an overall image of the lens barrel of the present embodiment. FIG. 2 is a plan view of the lens barrel. 3 to 5 are exploded perspective views of the main part of the lens barrel of the present embodiment. Among these, FIG. 3 mainly shows the exterior parts taken out from the constituent members of the lens barrel. FIG. 4 mainly shows a plurality of lens frames extracted from the constituent members of the lens barrel. FIG. 5 mainly shows the fixed frame and the focusing mechanism out of the constituent members of the lens barrel.

  6 to 9 are sectional views of the lens barrel. FIG. 6 is an overall cross-sectional view showing the focusing mechanism in the present lens barrel. 7 is a cross-sectional view taken along line [7]-[7] in FIG. 8 is a cross-sectional view taken along line [8]-[8] in FIG. FIG. 9 is a cross-sectional view taken along line [9]-[9] in FIG.

  10 to 13 are plan views showing the arrangement of the focusing mechanism by removing the exterior parts of the lens barrel. Of these, FIG. 10 is a plan view seen from the direction of arrow [10] in FIG. FIG. 11 is a plan view seen from the direction of arrow [11] in FIG. FIG. 12 is a plan view seen from the direction of arrow [12] in FIG. FIG. 13 is a plan view seen from the direction of arrow [13] in FIG.

  The exterior component 2 of the lens barrel 1 of the present embodiment includes a front decorative ring 31, a filter ring 32, a distance ring 33, a rear cover 34, and the like in order from the front end side, as mainly shown in FIGS. Consists of.

  The filter ring 32 is formed of a substantially cylindrical member that mainly covers the vicinity of the tip portion of the outer peripheral surface of the lens barrel 1, and a female screw for a filter for mounting accessories such as a filter is formed at the tip portion. . A substantially rectangular recess 32b (see FIG. 3) is formed on the outer peripheral surface of the filter ring 32. A hole 32c is formed in the bottom surface of the recess 32b. Then, a distance window 32a formed of a transparent resin member is fitted to the recess 32b so as to cover the hole 32c. Here, the distance window 32a is bonded and fixed to the recess 32b of the filter ring 32 with an adhesive member such as a double-sided tape. On the outer peripheral surface of the filter ring 32, a distance display 32ab (see FIG. 2) is provided in the vicinity of the distance window 32a by means such as printing or sticking a sticker.

  The filter ring 32 is fixed to the front surface of the fixed frame 16 to be described later by a screw 32x (connected from the reference [V] in FIG. 3 to the reference (32x) in FIG. 5).

  Although details will be described later, from this distance window 32a, an index line of a distance index plate 20 disposed integrally with a fourth group frame unit 14 (described later) disposed in the lens barrel 1 is provided. When 20a is exposed, the distance is displayed.

  The front decorative ring 31 covers the portion of the filter ring 32 near the outer periphery on the front side so as to conceal the internal structure and expose the first group lens 11a disposed in the vicinity of the central portion to secure an optical path. It is a substantially annular thin plate member provided for this purpose. The front decorative ring 31 is adhered and fixed to the flange portion near the front outer periphery of the filter ring 32 with an adhesive member such as a double-sided tape.

  The distance ring 33 is composed of a substantially cylindrical member that mainly covers the middle part of the lens barrel in the longitudinal direction on the outer peripheral surface of the lens barrel 1, and cooperates with a focusing mechanism 18 to be described later for manual focusing. It functions as an operating member when performing a focusing operation. For this purpose, the distance ring 33 is arranged to be rotatable around the optical axis O. That is, the distance ring 33 is a second frame means that rotates around the optical axis O in response to a user's manual operation.

  In this case, a distance ring spring 35 made of a thin plate spring member formed in an annular shape in which an urging force acts in the optical axis direction is disposed on the inner peripheral portion near the tip of the distance ring 33. The distance ring spring 35 is formed with a plurality of bent claws 35a (see FIG. 3). The bent claw portion 35a is prevented from rotating with respect to the distance ring 33 by being engaged with an engaged portion 33a (see FIG. 3) of the distance ring 33.

  In the assembled state of the lens barrel 1, the distance ring spring 35 is disposed in a state of being sandwiched between the front end face of the distance ring 33 and the rear end face of the filter ring 32. With this configuration, the distance ring 33 is pressed backward by the distance ring spring 35. Therefore, when the distance ring 33 rotates, friction in the rotational direction is generated by the distance ring spring 35 between the distance ring 33 and the filter ring 32. This frictional force prevents the distance ring 33 from easily rotating with a light force while securing the rotation of the distance ring 33.

  The rear cover 34 is made of a substantially cylindrical member that mainly covers the vicinity of the rear end portion of the outer peripheral surface of the lens barrel 1 and is fixed to the fixed frame 16 described later. The rear end of the rear cover 34 is disposed so that the rear end of the distance ring 33 is engaged. In this case, a dustproof sheet 36 (see FIGS. 3 and 6) is disposed between the front inner surface of the rear cover 34 and the rear outer peripheral surface of the distance ring 33. The dustproof sheet 36 is an annular sheet member provided to prevent fine dust and the like from entering the lens barrel 1 from the gap between the distance ring 33 and the rear cover 34.

  The internal components of the lens barrel 1 of the present embodiment are mainly composed of a first group frame unit 11, a second group frame unit 12, a diaphragm unit 15, and the like, as shown in FIGS. It includes a third group frame unit 13, a fourth group frame unit 14 (see FIG. 4 so far), a fixed frame 16, a focusing mechanism 18, a fixed lid 17, a lens side mount unit 37 (see FIG. 5 so far) and the like. Consists of a fixed frame unit and the like.

  The first group frame unit 11 is a unit configured by a first lens group 11a and a first group frame 11b that holds the first lens group 11a. The first group frame 11b is formed in a substantially annular shape, and the first lens group 11a is fixedly held at a substantially central portion. The first group frame 11b is fixedly held on the front side of a second group frame 12b described later by a plurality of screws 11x.

  The second group frame unit 12 is a unit configured by a second lens group 12a and a second group frame 12b that holds the second lens group 12a. The second group frame 12b is formed in a hollow substantially cylindrical shape, and the second lens group 12a is fixedly held at a substantially central portion. A diaphragm unit 15, a third group frame unit 13, and the like, which will be described later, are fixed and held inside the second group frame 12b. Further, the fourth group frame unit 14 is disposed so as to be movable back and forth in the direction along the optical axis O. The first group frame 11b is fixedly held on the front surface of the second group frame 12b as described above.

  A suspension shaft 21 (see FIGS. 4, 7, and 9) is disposed in the inner space of the second group frame 12 b so as to extend rearward in parallel with the optical axis O. As shown in FIG. 9, one end of the suspension shaft 21 is pivotally supported at a predetermined portion 12c on the front inner wall surface of the second group frame 12b, and the other end is a predetermined portion of the fixed lid 17 (described later in detail). It is pivotally supported at 17a. The suspension shaft 21 is slidably fitted in the through hole of the guide portion 14c of the fourth group frame unit 14. Thus, the fourth group frame unit 14 is configured to be guided by the suspension shaft 21 so as to freely advance and retract in the direction along the optical axis O (see FIG. 4 and the like). That is, the suspension shaft 21 is a guide shaft that guides the fourth group frame unit 14 (first frame means; described later) in a straight line parallel to the optical axis O.

  Further, in order to prevent the fourth group frame unit 14 from rotating about the suspension shaft 21 as a rotation center, a rotation regulating shaft 22 is disposed at a portion facing the suspension shaft 21 with the optical axis O interposed therebetween. Are arranged in parallel. That is, the rotation restricting shaft 22 is pivotally supported at a predetermined portion 12d on the front inner wall surface of the second group frame 12b, and the other end of the rotation restricting shaft 22 is a predetermined portion of the fixed lid 17, similar to the suspension shaft 21. It is pivotally supported at the portion 17b. Here, the predetermined part 12d of the front inner wall surface of the second group frame 12b is a part rotated about 180 degrees around the optical axis O with respect to the predetermined part 12b. The predetermined portion 17b of the fixed lid 17 is a portion rotated about 180 degrees around the optical axis O with respect to the predetermined portion 17a. The rotation restricting shaft 22 is engaged with the groove portion of the bearing portion 14 d of the fourth group frame unit 14. Thus, when the fourth group frame unit 14 is guided in the direction along the optical axis O by the suspension shaft 21 and moves forward and backward, the bearing portion 14 d moves along the rotation restricting shaft 22. As a result, the fourth group frame unit 14 can move smoothly only in the direction along the optical axis O.

  The fourth group frame unit 14 is a first frame means for holding a fourth lens group 14a which is a focusing lens (focusing lens). That is, the fourth group frame unit 14 is a unit configured by a fourth lens group 14a and a fourth group frame 14b that holds the fourth lens group 14a. The fourth group frame 14b is formed in a hollow, substantially cylindrical shape, and the fourth lens group 14a is fixedly held at the rear end of the substantially central portion. On the outer peripheral surface of the fourth group frame 14b, the guide portion 14c and the bearing portion 14d are provided so as to protrude from predetermined portions, respectively. As described above, the suspension shaft 21 and the rotation restriction shaft 22 are slidably fitted to the guide portion 14c and the bearing portion 14d, respectively.

  On the other hand, a spring hooking portion 14e (see FIG. 8) is formed on the guide portion 14c. One end of an urging member 19 (see FIGS. 4 and 8), which is a spring means made of, for example, an elastic coil spring or the like, is hung on the spring hooking portion 14e. The other end of the urging member 19 is hung on a spring hooking portion 17 c of the fixed lid 17. Therefore, the fourth group frame unit 14 is always pulled toward the fixed lid 17 by the urging force of the urging member 19.

  Further, a distance indicator plate 20 is integrally disposed on the guide portion 14c with screws 20x (see FIG. 4). An index line 20a is formed at the front end edge of the distance index plate 20, and as described above, the index line 20a can be observed through the distance window 32a. Therefore, when the fourth group frame unit 14 moves in the direction along the optical axis O along with the focusing operation described later, the distance indicator plate 20 also moves in the same direction at the same time. Although the distance index plate 20 moves, the index line 20a also moves in a predetermined direction. Therefore, the position of the fourth lens group 14a, which is a focusing lens, on the optical axis O is specified by the position of the index line 20a. It is configured to be able to.

  The aperture unit 15 is a unit that includes an aperture blade, an aperture motor 15a that drives the aperture blade, an aperture unit frame member 15b that holds these components, and the like. The aperture unit frame member 15b is formed in a substantially annular shape. The diaphragm unit frame member 15b is fixed and held inside the second group frame unit 12 by a plurality of screws 15x.

  The third group frame unit 13 is a unit configured by a third lens group 13a and a third group frame 13b that holds the third lens group 13a. The third group frame 13b is formed in a hollow, substantially cylindrical shape, and the third lens group 13a is fixedly held at a substantially central portion. The third group frame 13b is fixedly held inside the second group frame unit 12 by a plurality of screws 13x with the diaphragm unit 15 interposed therebetween.

  Among the fixed frame units, the fixed frame 16 is a frame member having a front end portion and a rear end portion formed in a large diameter and formed in a substantially cylindrical shape as a whole. In the inner space of the fixed frame 16, the first group frame unit 11, the second group frame unit 12, the aperture unit 15, the third group frame unit 13, and the fourth group frame unit 14 are stored in an assembled state. .

  On the front surface of the fixed frame 16, as described above, the filter ring 32 is fixedly held on the front surface of the fixed frame 16 by a plurality of screws 32x (from reference numeral (32x) in FIG. 5 to reference numeral [V] in FIG. 3). Connected to).

  A concave portion 16a (see FIG. 5) is formed on the outer peripheral surface at the tip large-diameter portion of the fixed frame 16. In the concave portion 16a, the front half portion of the distance indicator plate 20 is fitted and disposed so as to be movable in the optical axis O direction.

  Further, a focusing mechanism is provided in a hole portion 16b formed in a predetermined portion of a small diameter portion between the distal end large diameter portion and the rear end large diameter portion, which is a part on the outer peripheral surface of the fixed frame 16. 18 is fixedly arranged. The detailed configuration of the focusing mechanism 18 will be described later.

  Further, on the outer peripheral surface of the fixed frame 16, a linear encoder 16c constituting a part of the fourth frame position detecting means is fixedly disposed by a screw 16y or the like at a position adjacent to the vicinity of the focusing mechanism 18.

  A substantially annular fixed lid 17 is fixed to a portion near the rear end of the fixed frame 16 by a plurality of screws 17x. The diameter of the fixed lid 17 is smaller than the diameter of the rear end of the fixed frame 16. Accordingly, the fixing lid 17 is fixed to the fixing portion of the fixing frame 16 in a portion near the inside of the large diameter portion of the rear end of the fixing frame 16.

  Further, the rear end surface of the fixed frame 16 covers the fixed lid 17 and has a diameter substantially the same as the rear end large-diameter portion of the fixed lid 17 and is formed in a substantially annular shape. The lens side mount unit 37 is fixed to the rear surface of the fixed frame 16 by a plurality of screws 37x.

  Next, the focusing mechanism 18 in the lens barrel 1 of the present embodiment will be described in detail below with reference to FIGS. 10 to 13 in addition to FIGS.

  The focusing mechanism 18 is mainly constituted by a drive motor 18a, a lead screw 18b, a long gear 18c, a long gear support shaft 18d, a focus nut 18e, a roller member 18f as a rolling member, a base metal fitting 18g, and the like. It is configured.

  The drive motor 18a is a drive source for performing an automatic focusing operation, and for example, an electromagnetic motor such as a stepping motor is applied. A lead screw 18b is integrally formed on the rotational drive shaft of the drive motor 18a. The lead screw 18b is a shaft member that is provided in parallel with the optical axis O and that is rotated by the rotational output of the drive motor 18a.

  The drive motor 18a is provided with a base metal fitting 18g that rotatably supports the tip of the lead screw 18b. The base metal fitting 18g is a member that is formed by, for example, bending a thin plate-like metal member and constitutes a basic part of the focusing mechanism 18. The base metal fitting 18g is fixed on the outer peripheral surface of the fixed frame 16 with, for example, screws 18x while being attached to the drive motor 18a.

  A focus nut 18e is screwed into the lead screw 18b. The focus nut 18e has a spur gear portion on the outer peripheral surface and a female screw in the center hole. This female screw is screwed into the lead screw 18b. The spur gear portion meshes with a long gear 18c described later. As shown in FIG. 6 and the like, the nut contact portion 14f of the fourth group frame unit 14 contacts the focus nut 18e.

  Here, as described above, the fourth group frame unit 14 is always pulled toward the fixed lid 17 by the urging force of the urging member 19. Therefore, the nut contact portion 14f is always maintained in contact with the focus nut 18e.

  That is, the focus nut 18e (nut member) and the fourth group frame unit 14 (first frame) are maintained in contact with each other by the biasing member 19 (spring means).

  When only the lead screw 18b rotates, the focus nut 18e rotates along with the fourth group frame unit 14 (first frame means) in a direction parallel to the optical axis O with respect to the long gear 18c described later. It is a nut member which moves without rotating. The focus nut 18e is rotated along with the rotation of a long gear 18c, which will be described later, and moves with the fourth group frame unit 14 (first frame means) on the lead screw 18b in the optical axis direction.

  On the other hand, both ends of the long gear support shaft 18d are pivotally supported by the base metal fitting 18g in parallel with the lead screw 18b. The long gear support shaft 18d is rotatably fitted and inserted into the long gear 18c.

  The long gear 18c is a member having a long axis in the optical axis direction and a gear portion on the outer peripheral surface. The gear portion includes the focus nut 18e (nut member) and the fourth group frame unit 14 (first member). The frame means) is set to have a length necessary for moving in the direction of the optical axis O. The long gear 18c is disposed so as to be rotatable in parallel with the optical axis O. When the lead screw 18b rotates, the long gear 18c receives the non-rotating state of the distance ring 33 due to the action of the distance ring spring 35 as will be described later, while maintaining the non-rotating state of the focus nut 18e. This is a guide spur gear configured to guide the nut 18e in the direction of the optical axis O.

  The long gear 18c meshes with the outer peripheral spur gear portion of the focus nut 18e. Further, a roller member 18f is integrally disposed on one end side of the long gear 18c (in the present embodiment, the side closer to the drive motor 18a). Here, one end of the long gear 18c is formed in an oval or D-cut convex shape as shown in FIG. Correspondingly, the center hole of the roller member 18f is also formed in an oval shape or a D-cut shape. Therefore, by fitting the hole of the roller member 18f having the same shape with the convex portion of the long gear 18c, the long gear 18c and the roller member 18f are integrally formed and can be rotated integrally.

  The diameter of the roller member 18f is set to be slightly larger than the diameter of the long gear 18c. The outer peripheral surface of the roller member 18f is in contact with the inner peripheral surface 33f (see FIG. 7) of the distance ring 33. Accordingly, when the distance ring 33 receives an external force (for example, an operation by a user) and rotates around the optical axis O, the rotational force of the distance ring 33 is frictionally transmitted to the roller member 18f. As a result, the long gear 18c also rotates together with the roller member 18f.

  As described above, the roller member 18f functions as a transmission unit that transmits the rotational force generated by manual operation of the distance ring 33 (second frame unit) to the long gear 18c (guide spur gear).

  That is, the transmission means is provided integrally with the distance ring 33 (inner peripheral surface of the second frame means) and the long gear 18c (guide spur gear), and the distance ring 33 (second frame means). ) Is rotated by a roller member 18f, which is a rolling member that rolls in contact with the inner periphery thereof.

  The roller member 18f, which is a rolling member, has at least a surface that is in rolling contact with the distance ring 33 (second frame means) and has elasticity and a material having a large frictional force, such as a rubber material. Etc. are constituted.

  On the other hand, as described above, the distance indicator plate 20 is fixedly disposed on the guide portion 14c of the fourth group frame unit 14 by screws 20x. Here, the distance indicator plate 20 is integrally attached with an engaging member 20b that constitutes a part of the fourth group frame position detecting means and engages with the detecting portion (input moving portion) 16cc of the linear encoder 16c. (See FIGS. 12 and 13). The engaging member 20b is a member formed with a notch at the tip, and is fixed to the guide portion 14c of the fourth group frame unit 14 together with the distance indicator plate 20 by the screw 20x. And the detection part 16cc of the linear encoder 16c is engaging with the notch part of the engaging member 20b. Therefore, when the fourth group frame unit 14 moves in the direction along the optical axis O and the distance indicator plate 20 moves in the same direction, the engaging member 20b also moves in the same direction. Then, the engaging member 20b acts on the detection unit 16cc of the linear encoder 16c. The detection output signal of the linear encoder 16c is transmitted to a control circuit composed of a CPU or the like mounted on a lens substrate (not shown). As a result, the position of the fourth group frame unit 14 is detected.

  In the lens barrel 1 of the first embodiment configured as described above, the operation when performing the focusing operation will be described below.

  First, the operation during the automatic focusing operation will be described. When the user performs a predetermined operation on the side of the camera (not shown) to which the lens barrel 1 is attached, for example, a first release operation, the camera cooperates with the lens barrel 1 of the present embodiment to perform automatic alignment. The execution of the focusing operation is started.

  In this case, when the drive motor 18a is driven, the lead screw 18b rotates. At this time, the focus nut 18e is connected to the distance ring 33 via the long gear 18c and the roller member 18f, but a frictional force is generated between the distance ring 33 and the roller member 18f. The ring 33 is in a non-rotating state. Accordingly, the focus nut 18e does not rotate even if the lead screw 18b rotates, so that it is in a state where rotation is restricted.

  As described above, since the focus nut 18e does not rotate, when the drive motor 18a is driven and the lead screw 18b rotates, the focus nut 18e screwed to the focus nut 18e does not rotate. Move forward and backward in the direction along O. At this time, the nut contact portion 14f of the fourth group frame unit 14 is always in contact with the focus nut 18e. Therefore, as the focus nut 18e moves forward and backward in the optical axis O direction, the fourth group frame unit 14 also moves forward and backward in the same direction. The amount of movement at this time is detected by the linear encoder 16c. A control circuit (not shown) controls the movement of the fourth group frame unit 14 based on the detection output of the linear encoder 16c.

  Next, the operation during the manual focusing operation will be described. A manual focusing operation is started when the user rotates the distance ring 33 around the optical axis O. When the distance ring 33 is rotated, the roller member 18f is rotated by friction between the distance ring inner periphery and the roller member 18f, and the long gear 18c is rotated accordingly, and the focus nut 18e is rotated. At this time, the lead screw 18b is not rotated by the detent torque of the drive motor 18a. Therefore, the focus nut 18e moves forward and backward in the direction along the optical axis O while rotating around the screw of the non-rotating lead screw 18b following the rotation of the long gear 18c. As a result, the fourth group frame unit 14 moves forward and backward in the same direction.

  As described above, when the user rotates the distance ring 33 by manual operation, the focus nut 18e moves in the direction of the optical axis O. Therefore, the operation of switching the mechanism is performed from the state where the automatic focusing operation can be performed. The manual focusing operation can be performed as it is.

  When performing the manual focusing operation, when the focus nut 18e reaches one end within the movable range, the user tries to further rotate the distance ring 33 in the same direction. To do. At this time, if the focus nut 18e continues to rotate in accordance with the rotation operation of the distance ring 33, damage or the like due to overloading of the meshing portion of the outer peripheral spur gear portion of the focus nut 18e and the long gear 18c occurs. There is a fear.

  However, the focusing mechanism 18 in the lens barrel 1 of the present embodiment is configured to transmit driving force between the distance ring 33 and the long gear 18c via the roller member 18f. Therefore, in the situation as described above, when an overload occurs between the long gear 18c and the focus nut 18e, a slip occurs between the distance ring 33 and the roller member 18f. Therefore, after the roller member 18f, the transmission of the driving force to the long gear 18c is cut off, so that an overload is applied to the constituent members (particularly the focus nut 18e) of the focusing mechanism 18A and the fourth group frame unit 14. Is configured to not.

  That is, when the distance ring 33 is rotated, if an overload occurs on the focus nut 18e meshing with the long gear 18c, a slip occurs between the inner peripheral surface of the distance ring 33 and the roller member 18f. Thereby, the transmission means (the inner peripheral surface of the distance ring 33 and the roller member 18f) is a slip clutch means interposed between the distance ring 33 (second frame means) and the focus nut 18e (nut member). Function as.

  As described above, according to the first embodiment, during the automatic focusing operation by the drive motor 18a, the rotation of the focus nut 18e screwed to the lead screw 18b is restricted and moved forward and backward, while the distance During manual focusing operation by the ring 33, the driving force in the rotation direction of the distance ring 33 is mechanically transmitted to the focus nut 18e, and the focus nut 18e screwed with the lead screw 18b whose rotation is restricted is rotated. This is configured to move forward and backward.

  Therefore, with such a configuration, it is possible to perform the manual focusing operation immediately from the state in which the automatic focusing operation can be performed by merely rotating the distance ring 33 without performing any mechanism switching operation. .

[Second Embodiment]
Next, a lens barrel according to a second embodiment of the present invention will be described below with reference to FIGS. The configuration of this embodiment is basically the same as that of the first embodiment described above, except for the configuration of the focusing mechanism. Therefore, the same reference numerals are used for the same constituent members as those in the first embodiment described above, and in the following description, only portions different from the configurations in the first embodiment will be described in detail.

  FIG. 14 is an enlarged exploded perspective view showing a main part extracted from the constituent members related to the focusing mechanism in the lens barrel of the second embodiment of the present invention. 15 is a cross-sectional view of a state in which only constituent members related to the focusing mechanism of FIG. 14 are assembled, and is a cross-sectional view taken along line [15]-[15] of FIG. FIG. 16 is a plan view seen from the direction of arrow [16] in FIG.

  The focusing mechanism 18A of this embodiment is mainly configured by a drive motor 18a, a lead screw 18b, a base metal fitting 18g, an outer peripheral gear 18h, a ring spring 18i, an E ring 18j, a nut 18k, and the like. In the present embodiment, the drive motor 18a, the lead screw 18b, the base bracket 18g, and the like have the same shape as in the first embodiment.

  In the present embodiment, a nut portion set 24 is provided in place of the focus nut in the first embodiment described above, and the long gear 18c and the long gear support shaft 18d are eliminated.

  The nut portion set 24 includes a nut 18k having a female screw threadedly engaged with the lead screw 18b in the center hole, an outer peripheral gear 18h having a spur gear on the outer peripheral surface, and a thin plate leaf spring member inserted through the shaft portion of the nut 18k. The ring spring 18i is formed in a ring shape, and the E-ring 18j is fitted into the circumferential groove of the nut 18k to prevent the ring spring 18i from coming off.

  After the shaft portion of the nut 18k is fitted in the center hole of the outer peripheral gear 18h, it is inserted into the ring spring 18i, and in this state, the E ring 18j is locked to the circumferential groove portion of the coaxial portion. In this case, the ring spring 18i is in a state of being pressed and clamped between one end surface of the outer peripheral gear 18h and the opposing surface of the E ring 18j. Therefore, the ring spring 18i presses the other end surface of the outer peripheral gear 18h toward the flange surface of the nut 18k in a direction parallel to the optical axis O. The shaft portion of the nut 18k is integrated with the central hole of the outer peripheral gear 18h. Therefore, when either one of the nut 18k or the outer peripheral gear 18h is rotated, the both are rotated integrally by the fitting force of both and the pressing force of the ring spring 18i. On the other hand, for example, when a rotation amount greater than a predetermined value, that is, a force greater than a friction torque generated by the urging force of the ring spring 18i is applied to the outer peripheral gear 18h, slip occurs between the outer peripheral gear 18h and the nut 18k. Is set. In this case, only the outer peripheral gear 18h rotates as a separate body.

  The female screw of the nut portion set 24 is screwed into the lead screw 18b. In this state, the outer peripheral gear 18h meshes with an internal gear 33Aa formed on the inner peripheral surface of the distance ring 33A. Here, the internal gear 33 </ b> Aa is a transmission unit that transmits the turning force by the manual operation of the distance ring 33 </ b> A (second frame unit) to the fourth group frame unit 14 through the nut set 24.

  In other words, this transmission means comprises an internal gear 33Aa (internal gear) that is provided on the inner periphery of the distance ring 33A (second frame means) and meshes with the outer peripheral gear 18h (spur gear) of the nut portion set 24. When the distance ring 33A (second frame means) rotates, the internal gear 33Aa (spur gear) is configured to rotate. Other configurations are the same as those in the first embodiment.

  The operation of the lens barrel of the second embodiment configured as described above will be briefly described below.

  First, during the automatic focusing operation, when the user performs a first release operation or the like, the drive motor 18a is driven and the lead screw 18b rotates. At this time, the outer peripheral gear 18h of the nut portion set 24 meshes with the internal gear 33Aa of the distance ring 33A, and the distance ring 33 is in a non-rotating state by the above action of the distance ring spring 35. Therefore, the nut part set 24 is in a state where the rotation of the nut part set 24 is restricted, that is, the nut part set 24 does not rotate even if the lead screw 18b rotates. When the drive motor 18a is driven in this state and the lead screw 18b rotates, the nut 18k moves forward and backward in the direction along the optical axis O, and the fourth group frame unit 14 moves forward and backward in the same direction in conjunction with this.

  Next, at the time of manual focusing operation, the user rotates the distance ring 33 </ b> A around the optical axis O against the frictional force caused by the urging force of the distance ring spring 35. When the distance ring 33 is rotated, the nut portion set 24 is rotated via the outer peripheral gear 18h meshing with the internal gear 33Aa. At this time, the lead screw 18b is not rotated by the detent torque of the drive motor 18a. Therefore, the nut portion set 24 moves back and forth in the direction along the optical axis O while rotating. As a result, the fourth group frame unit 14 moves forward and backward in the same direction.

  Assume that the distance ring 33A is further rotated in the same direction after the nut assembly 24 reaches one end within the movable range during the manual focusing operation. At this time, even if the nut portion set 24 continues to rotate according to the rotation operation of the distance ring 33A, slip occurs between the outer peripheral gear 18h and the nut 18k. As a result, the outer peripheral gear 18h is idled to prevent an overload from being applied to the constituent members of the focusing mechanism 18A.

  In the focusing mechanism 18A in the lens barrel of the present embodiment, the nut portion set 24 for moving the fourth group frame unit 14 back and forth in the direction of the optical axis O is constituted by two members, an outer peripheral gear 18h and a nut 18k. The driving force is transmitted between the two by the urging force of the ring spring 18i. With such a configuration, an overload is suppressed from being applied to the focusing mechanism 18A and the fourth group frame unit 14 as in the first embodiment.

  Accordingly, the ring spring 18i (spring member) presses the outer peripheral gear 18h (spur gear) of the nut portion set 24 and the nut 18k of the nut portion set 24 in a direction parallel to the optical axis O. At the same time, the ring spring 18i functions as a slip clutch means when an overload occurs in the nut portion set 24.

  As described above, according to the second embodiment, substantially the same effect can be obtained although the configuration is slightly simplified with respect to the first embodiment.

[Third Embodiment]
Next, a lens barrel according to a third embodiment of the present invention will be described below with reference to FIGS. The configuration of this embodiment is basically the same as that of the first and second embodiments described above, except for the configuration of the focusing mechanism. Accordingly, the same reference numerals are used for the same constituent members as those in the first and second embodiments described above, and in the following description, only the portions different from the configurations of the first and second embodiments described above are described in detail. Describe.

  FIG. 17 is an enlarged exploded perspective view of a main part taken out and showing components and exterior parts related to the focusing mechanism in the lens barrel of the third embodiment of the present invention. 18 is a cross-sectional view of a state in which components and exterior parts related to the focusing mechanism of FIG. 17 are assembled, and is a cross-sectional view taken along line [18]-[18] of FIG. 19 is a cross-sectional view taken along the line [19]-[19] in FIG.

  In the lens barrel of this embodiment, a distance ring spring 35 is provided between the filter ring 32 and the distance ring 33B, which are exterior parts, and the distance ring spring 35 presses the distance ring 33B backward. This is the same configuration as in the first and second embodiments described above.

  The present embodiment is different in that an internal gear ring 38 is disposed behind the distance ring 33B and inside the rear cover 34. The internal gear ring 38 is an annular member having an internal gear 38a on the inner peripheral surface.

  The second frame means in the present embodiment has a distance ring 33B that is a first rotating ring that is manually rotated, and an internal gear 38a that meshes with an inner peripheral surface of a nut gear 18m (nut member; described later). It is constituted by a two-piece annular member with an internal gear ring 38 that is a second rotating ring that rotates together with the distance ring 33B. The distance ring 33B (first rotation ring) and the internal gear ring 38 (second rotation ring) are urged in the direction of the optical axis O by the distance ring spring 35 (spring member), and are integrated by frictional force. Configured to be combined.

  The front end surface 38b of the internal gear ring 38 is in contact with an inward flange portion 33Bb formed in the vicinity of the rear end edge on the inner peripheral side of the distance ring 33B. As described above, since the distance ring 33B is pushed rearward by the urging force of the distance ring spring 35, the internal gear ring 38 is also pushed in the same direction via the distance ring 33B.

  On the other hand, the rear end edge of the internal gear ring 38 is in contact with a ball ring 39 provided in the vicinity of the rear end edge portion on the inner peripheral side of a fixed frame (not shown). As a result, the ball ring 39 receives a backward pressing of the internal gear ring 38 by the distance ring spring 35.

  The ball ring 39 is formed of a ring-shaped member, and a plurality of ball members 39a are arranged at equal intervals in the circumferential direction on the contact surface side with the internal gear ring 38. The plurality of ball members 39a come into contact with a thrust surface 38c provided in the vicinity of the rear end edge of the inner periphery of the internal gear ring 38 to smoothly rotate the internal gear ring 38. Functions as a bearing.

  The internal gear ring 38 is a transmission means for transmitting the turning force by manual operation of the distance ring 33B (second frame means) to the fourth group frame unit 14 via the nut gear 18m.

  On the other hand, the focusing mechanism 18B in this embodiment is mainly configured by a drive motor 18a, a lead screw 18b, a base metal fitting 18g, a nut gear 18m, and the like. Among these, the drive motor 18a, the lead screw 18b, and the base metal fitting 18g have the same shapes as those in the first embodiment. Of the focusing mechanism 18B, the nut gear 18m is a nut member having a female screw that engages with the lead screw 18b in the center shaft hole and a spur gear portion that meshes with the internal gear ring 38 on the outer peripheral surface. Other configurations are substantially the same as those of the first and second embodiments described above.

  The operation of the lens barrel of the third embodiment configured as described above will be briefly described below.

  First, during the automatic focusing operation, the drive motor 18a is driven and the lead screw 18b rotates. At this time, the spur gear portion of the nut gear 18m and the internal gear 38a of the internal gear ring 38 are in mesh with each other, and the distance ring 33B is in a non-rotating state due to the frictional force of the distance ring spring 35. Therefore, even if the lead screw 18b rotates, the nut gear 18m does not rotate, so to speak, the rotation is restricted. That is, when the distance ring 33B is in the non-rotating state, the nut gear 18m maintains the non-rotating state.

  When the drive motor 18a is driven and the lead screw 18b rotates in this state, the nut gear 18m is moved back and forth in the direction of the optical axis O by the action of the lead screw 18b and the female screw of the nut gear 18m while maintaining the non-rotating state. Thereby, the fourth group frame unit 4 also moves forward and backward in the same direction.

  Next, during the manual focusing operation, the distance ring 33B is manually operated in the rotation direction around the optical axis O by the user. Then, the internal gear ring 38 sandwiched between the distance ring 33B and the ball ring 39 smoothly rotates integrally with the distance ring 33B. At this time, the lead screw 18b is not rotated by the detent torque of the drive motor 18a. Therefore, the nut gear 18m rotates and moves forward and backward in the direction along the optical axis O by the action of the lead screw 18b and the female screw of the nut gear 18m. As a result, the fourth group frame unit 14 moves forward and backward in the same direction.

  Assume that the distance ring 33B is further rotated in the same direction after the nut gear 18m reaches one end within the movable range during the manual focusing operation. At this time, if the nut gear 18m continues to rotate according to the rotation operation of the distance ring 33B, the flange portion 33Bb of the distance ring 33B and the internal gear ring are between the distance ring 33B and the internal gear ring 38. Slip occurs between the front end surface 38 b of the plate 38. As a result, even if the distance ring 33B is rotated, the internal gear ring 38 is in a non-rotating state, thereby preventing an overload from being applied to the constituent members of the focusing mechanism 18B.

  As described above, according to the third embodiment, substantially the same effects as those of the first and second embodiments can be obtained.

  In each of the above embodiments, the fourth group frame unit 14 as the first frame means configured to be movable back and forth in the direction along the optical axis O holds the focusing lens and moves forward and backward for focusing. It is a frame member. However, the configuration of the present invention is not limited to this configuration and application. For example, it can be applied to a frame member that holds a zoom lens and moves forward and backward in the optical axis O direction for zooming. It is.

  The present invention is not limited to the above-described embodiments, and it is needless to say that various modifications and applications can be implemented without departing from the spirit of the invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the above-described embodiment, if the problem to be solved by the invention can be solved and the effect of the invention can be obtained, this constituent requirement is deleted. The configured structure can be extracted as an invention.

DESCRIPTION OF SYMBOLS 1 ... Lens barrel, 2 ... Exterior part, 11 ... First group frame unit, 12 ... Second group frame unit, 13 ... Third group frame unit, 14 ... Fourth group frame unit, 15 ... Aperture unit , 16 ... fixed frame, 16c ... linear encoder, 17 ... fixed lid, 18, 18A, 18B ... focusing mechanism, 18a ... drive motor, 18b ... lead screw, 18c ... long gear, 18d ... Long gear support shaft, 18e ... Focus nut, 18f ... Roller member, 18g ... Base bracket, 18h ... Outer gear, 18i ... Ring spring, 18j ... E ring, 18k ... Nut, 18m ... Nut gear, 18x ... screw, 19 ... biasing member, 20 ... distance indicator plate, 20 ... indicator line, 20b ... engagement member, 21 ... suspension shaft, 21 ... guide shaft, 22 ... rotation restricting shaft , 24 …… 33, 33A, 33B ... distance ring, 33a ... engaged part, 33Aa ... internal gear, 33Bb ... inward flange part, 34 ... rear cover, 35 ... distance ring spring, 35a ... bent claw part, 36 ... dustproof sheet, 37 ... lens side mount unit, 38 ... internal gear ring, 38a ... internal gear, 39 ... ball ring, 39a ... ball member

Claims (2)

In the lens barrel,
A driving source;
A lead screw that is provided in parallel with the optical axis and rotates by the rotational output of the drive source;
First frame means;
A guide shaft for guiding the first frame means in a straight line parallel to the optical axis;
A nut member having a spur gear portion on an outer peripheral surface, having a screw to be screwed with the lead screw, and movable along with the first frame means in parallel with the optical axis as the lead screw rotates;
The nut member meshes with the spur gear portion of the nut member and can be rotated around the optical axis. When the lead screw rotates, the nut member is not rotated and the nut member can be moved in the optical axis direction and subjected to manual operation. Second frame means having an internal gear for rotating the nut member to move the nut member in the direction of the optical axis when rotating around the optical axis;
An urging member that maintains a state in which the nut member and the first frame means are always in contact with each other;
Clutch means provided between the second frame means and the nut member;
A lens barrel characterized by comprising: In the lens barrel,
A driving source;
A lead screw that is provided in parallel with the optical axis and rotates by the rotational output of the drive source;
First frame means;
A guide shaft for guiding the first frame means in a straight line parallel to the optical axis;
Together with the nut screwed with the lead screw have a female thread, and an outer peripheral gear having spur gears on the outer peripheral surface has a center hole to fit the shank of the nut, and the nut and the outer peripheral gear ungated, a nut portion assembly comprising a spring for pressing to the optical axis direction as you relative rotation,
It can mesh with the spur gear of the nut part set and rotate around the optical axis, and when the lead screw rotates, the nut part set is non-rotated and the nut part set is movable in the optical axis direction. Receiving the second frame means having an internal gear that rotates the nut portion set and moves the nut portion set in the direction of the optical axis when rotating around the optical axis;
An urging member that maintains the state in which the nut portion set and the first frame means are always in contact with each other;
A lens barrel characterized by comprising:

Images