JP5168565B2 - Lens barrel and camera - Google Patents

Description

  The present invention relates to a lens barrel and a camera.

Conventionally, a locking device for correction means (hereinafter referred to as a locking device) that restricts movement of a support frame that holds a correction lens in a direction perpendicular to the optical axis using a lock ring is known (see the following publication). ). In this locking device, the gear mounted on the rotation shaft of the rotor and the gear of the lock ring are meshed to rotate the lock ring around the optical axis and lock using a regulating member that regulates the rotation of the lock ring. Lock the ring in the locked / unlocked position.
Japanese Patent No. 3461259

  However, in the above-described locking device, since the regulating member is disposed close to the rotor, when the rotor is driven to lock the lock ring at the lock position / unlock position, the lock ring is separated from the rotor by the regulating member. A force in the direction of separating acts, the amount of meshing between the gear of the rotor and the gear of the lock ring decreases, and the play increases. As a result, there is a problem that it takes a long time until the lock ring is stationary, and the position of the lock ring is easily changed by vibration / impact after the stationary state.

  An object of the present invention is to provide a lens barrel and a camera capable of quickly and reliably stopping a first member.

In order to solve the above-mentioned problem, the invention according to claim 1 is to hold a fixed frame and a lens, and is supported by the fixed frame so as to be movable in a direction perpendicular to the optical axis of the lens, and a plurality of protrusions are provided on the outer periphery. A lens holding frame formed side by side at a predetermined interval, and an annular shape surrounding each of the protrusions, and crests and troughs are alternately formed on the inner periphery, and the protrusions and the troughs are and an unlocked position for allowing movement of the counter to a direction perpendicular to the optical axis of the lens holding frame, the projection and the peaks and is opposed to the direction perpendicular to the optical axis of the lens holding frame A lock member supported by the fixed frame so as to be rotatable between a lock position that restricts movement of the lock member and a gear portion provided on an outer peripheral portion of the lock member, and the lock member via the gear portion For rotating the motor between the unlock position and the lock position. Gear and a first rotation limiting member for receiving said locking member to limit rotation of the first rotational direction of the locking member in the unlocking position, the first of said locking member in said locking position A second rotation restricting member that receives the lock member so as to restrict rotation in a second rotation direction opposite to the rotation direction, and the lock member contacts the first rotation restricting member. Of the reaction force received by the lock member from the first rotation limiting member, the component force in the direction connecting the rotation center of the drive gear and the rotation center of the lock member, and the lock member is the second rotation limit. Of the reaction force received by the lock member from the second rotation restricting member when contacting the member, the component force in the direction connecting the rotation center of the drive gear and the rotation center of the lock member is approximately. Wherein the equivalent.

According to a second aspect of the invention, in the lens barrel according to claim 1, a position located between the locking member the locking member is brought into contact with said first rotation restricting member is brought into contact with the second rotation limiting member Is characterized by being substantially symmetrical with respect to a straight line connecting the rotation center of the drive gear and the rotation center of the lock member .

According to a third aspect of the invention, in the lens barrel according to claim 1 or 2, and the first and the second rotation limiting member and the rotation restriction member is equal to or is integral.

According to a fourth aspect of the present invention, in the lens barrel according to any one of the first to third aspects, the first rotation limiting member and the second rotation limiting member are elastic members. .

According to a fifth aspect of the present invention, in the lens barrel according to any one of the first to fourth aspects, the lens barrel includes a motor that rotates the drive gear, and the rotation stop holding force in a non-excited state of the motor characterized by holding the first locking member at each position of the lock position and the unlock position.

A camera according to a sixth aspect of the invention includes the lens barrel according to any one of the first to fifth aspects, and a camera body to which the lens barrel is attached.

  According to the present invention, the first member can be quickly and reliably stopped.

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

  FIG. 1 is a cross-sectional view showing a cross section of a lens barrel according to an embodiment of the present invention. In FIG. 1, illustration of a motor, a lock ring, and the like is omitted.

  The lens barrel 100 includes an autofocus mechanism (a motor for driving the second lens frame 12 is not shown). The lens barrel 100 houses a plurality of lenses (optical members) L1 to L5 constituting a zoom lens system. With this zoom lens system, the focal length can be continuously changed from the wide side to the tele side. FIG. 1 shows the positional relationship of the lenses L1 to L5 on the tele side. A camera body 50 is attached to the rear end portion of the lens barrel 100.

The lens L1 is held by the first lens frame 11, the lens L2 is held by the second lens holding frame 12, the lens L3 is held by the third lens frame 13, and the lens L4 is a fourth lens holding frame (lens holding frame). 14, the lens L5 is held by the fifth lens holding frame 15.

  For example, when zooming (when changing the focal length from the wide side to the tele side), the lenses L1 to L5 move along the optical axis A from the camera body 50 side (right side in FIG. 1) to the subject side (left side in FIG. 1). Thus, the entire length of the lens barrel 100 becomes longer.

  At this time, the lens L1, the lens L2, and the lens L4 move independently. The lens L3 and the lens L5 move integrally because the third lens frame 13 and the fifth lens holding frame 15 are integrally coupled.

  During autofocus, the second lens frame 12 holding the lens L2 is driven along the optical axis A by the motor, and the lens L2 also moves along the optical axis A.

The lens L4 is a camera shake correction (VR) lens, and when performing camera shake correction (when VR is on), the fourth lens holding frame 14 holding the lens L4 is moved in a plane perpendicular to the optical axis A. As will be described later, the fourth lens holding frame 14 is provided with a lock ring (lock member) 20 (see FIGS. 2 to 4 ) for preventing the fourth lens holding frame 14 from moving. The lock ring 20 has an optical axis between an unlock position that allows movement of the lens L4 in a direction orthogonal to the optical axis A and a lock position that locks movement of the lens L4 in a direction orthogonal to the optical axis A. Able to forward and reverse around A.

  FIG. 2 is a view of the lock ring 20 as viewed from the camera body 50 side, and FIGS. 3 and 4 are conceptual views showing a cross section of the fourth lens holding frame 14. FIG. 3 shows an image stabilization non-control position (lock position) where camera shake correction is not performed, and FIG. 4 shows an image stabilization control position (unlock position) where camera shake correction is performed.

  The fourth lens holding frame 14 that holds the lens L4 is held by the fixed frame 17 so as to be movable in a direction orthogonal to the optical axis A. A plurality of spheres 6 are arranged between the fourth lens holding frame 14 and the fixed frame 17, and the fourth lens holding frame 14 and the fixed frame 17 are optically connected to each other by a plurality of springs 16 (see FIG. 2). It is urged to approach in the A direction.

  The fixed frame 17 is provided with a position sensor (not shown) for detecting the amount of movement of the lens L4 in the direction orthogonal to the optical axis A. As the position sensor, for example, a hall element capable of precise position detection is used. For example, a magnet is disposed at a position facing the Hall element of the fourth lens holding frame 14 to detect the movement amount of the lens L4. According to the analog output Hall element, the movement amount of the lens L4 can be detected with a resolution of the order of several μm.

  A lock ring 20 for locking the lens holding frame 14 is slidably supported on the fixed frame 17. The lock ring 20 has an annular shape, and crests 22 and troughs 23 are alternately formed on the inner peripheral surface thereof (see FIG. 2). The lock position of the lock ring 20 (see FIGS. 2 and 3) is when the peak portion 22 of the lock ring 20 and the protrusion 14a of the fourth lens holding frame 14 face each other, and the valley portion 23 of the lock ring 20 and the fourth lens. The unlocking position of the lock ring 20 is when the protrusion 14a of the holding frame 14 faces. A rotation limiting rubber 40 is attached to the fixed frame 17.

The lock ring 20 is rotated around the optical axis A by the motor 30. A motor gear (drive gear) 31 provided on the output shaft of the motor 30 meshes with a gear portion 21 formed on the outer peripheral surface of the lock ring 20, and the rotational force of the motor 30 is transmitted to the lock ring 20. The lock ring 20 is driven to the lock position and the unlock position by the forward rotation and reverse rotation of the motor 30. As the motor 30, a DC motor, a stepping motor, an ultrasonic motor, or the like can be used. The motor 30 and the motor gear 31 constitute driving means for the lock ring 20 .

When the lock ring 20 is driven to the lock position and the unlock position, the lock ring 20 abuts against the rotation limiting rubber (elastic member) 40 and stops at the lock position and the unlock position. The rotation limiting rubber 40 functions as a first rotation limiting member and a second rotation limiting member . Rotation limiting rubber 40 is shaped substantially symmetrical against a virtual line V A below. The rotation limiting rubber 40 and the motor 30 are disposed at positions displaced by 180 ° in the circumferential direction around the optical axis A.

  At the time of locking and unlocking, the rotation limiting rubber 40 is located at a position where the lock ring 20 is substantially symmetric with respect to a virtual line VA connecting the optical axis A (the rotation center of the lock ring 20) and the rotation center of the motor 30. Abut. After the lock ring 20 comes into contact with the rotation limiting rubber 40, no electric power is supplied to the motor 30, but the lock ring 20 is locked and unlocked by cogging torque (rotation stop holding force) generated in the non-excited motor 30. Held in position. Conventionally, a drive source that does not generate cogging torque, such as a voice coil motor, has been used, so that the lock ring can be set in each rotation-restricted position so that the lock ring does not rotate due to vibration or impact when power is not supplied to the drive source. However, it is not necessary to provide a click mechanism by using a motor that generates cogging torque.

  Next, a lock / unlock operation by forward / reverse rotation of the lock ring 20 will be described with reference to FIGS.

When the motor 30 is driven from the state shown in FIGS. 2 and 3 (locked state) and the lock ring 20 is rotated clockwise (first rotation direction) , for example, the protrusion 14 a faces the valley 23. Move to unlock position. As a result, the lock ring 20 changes from a locked state where the lens L4 cannot be moved to an unlocked state where the lens L4 can be moved. Based on the amount of movement detected by a sensor (not shown), the fourth lens holding frame 14 is driven in a direction to cancel the shake, and the camera shake is corrected.

Conversely, when the lock ring 20 is in the unlocked state, in order to change from this state to the locked state, the motor 30 is driven to rotate the lock ring 20 counterclockwise (second rotational direction) (reverse rotation). You can do it. Then, the protrusion 14a moves to the lock position facing the mountain portion 22. As a result, the lock ring 20 changes from an unlocked state in which the lens L4 can be moved to a locked state in which the lens L4 cannot be moved.

When locked, the lock ring 20 receives a reaction force 27 from the rotation limiting rubber 40 when it hits the rotation limiting rubber 40. Further, when unlocked, the lock ring 20 receives a reaction force 28 from the rotation limiting rubber 40 when it hits the rotation limiting rubber 40. The lock ring 20 contacts one end 25 of the rotation limiting rubber 40 when locked, and the lock ring 20 contacts the other end 26 of the rotation limiting rubber 40 when unlocked.

Divided reactive force 27 and the direction of the component force 27V orthogonal to a virtual line VA direction parallel partial forces 2 7P virtual line VA, virtual direction parallel partial forces 2 8P reaction force 28 to the virtual line VA When divided into the component force 28V in the direction orthogonal to the line VA, the direction of the component force 27P and the direction of the component force 28P are the same, and the magnitude of the component force 27P and the magnitude of the component force 28P are substantially equal. The directions of the component forces 27P and 28P are directions in which the motor gear 31 and the gear portion 21 are engaged with each other (direction in which the lock ring 20 is pressed against the motor 30).

  According to this embodiment, when the motor 30 is driven and the lock ring 20 is disposed at the lock position / unlock position, the meshing amount between the motor gear 31 and the gear portion 21 of the lock ring 20 increases (the motor gear 31 and the gear). The engagement play with the portion 21 is reduced) and no large play is generated. As a result, it is possible to prevent the lock ring 20 from being prolonged until the lock ring 20 is stationary, or to change the position of the lock ring 20 due to vibration / impact after the stationary, and the lock ring 20 can be quickly and reliably stationary. it can.

  Moreover, the direction of the component force 27P and the direction of the component force 28P are the same at the time of locking and unlocking, and the magnitude of the component force 27P and the magnitude of the component force 28P are substantially equal. Thus, when the lock ring 20 hits the rotation limiting rubber 40, the movement until the lock ring 20 is stopped is the same, and the time until the lock ring 20 stops is the same when locked and unlocked. As a result, the time from when the lock ring 20 hits the rotation restricting rubber 40 until the lock ring 20 is completely stopped and the next operation such as photographing can be started is the same at the time of locking and unlocking. It is possible to change the time from when the lock ring 20 hits the rotation restricting rubber 40 until the next operation can be started at the time of locking and unlocking, or to provide a wasteful waiting time according to the longer time. Disappear. Further, in order to change the waiting time in the rotation direction, it is not necessary to detect which direction the lock ring 20 is rotating, and it is only necessary to detect that the lock ring 20 is rotating. Can also be done easily.

In the above embodiment, the first rotation limiting member and the second rotation limiting member are configured by the rotation limiting rubber 40, but the first rotation limiting member and the second rotation limiting member are separately provided. The rotation limiting rubber may be used.

  The elastic member is not limited to the rotation limiting rubber 40, and may be a leaf spring or the like as long as it has elasticity.

FIG. 1 is a cross-sectional view showing a cross section of a lens barrel according to an embodiment of the present invention. FIG. 2 is a view of the lock ring as seen from the camera body side. FIG. 3 is a conceptual diagram showing a cross section of the fourth lens holding frame. FIG. 4 is a conceptual diagram showing a cross section of the fourth lens holding frame.

20: lock ring ( lock member ) , 30 : motor, 31: motor gear (drive gear) , 40: rotation limiting rubber (first and second rotation limiting members) , 50: camera body, 100: lens barrel, A: Optical axis, L1 to L5: Lens (optical member ).

Claims (6)

A fixed frame,
A lens holding frame that holds a lens and is supported by the fixed frame so as to be movable in a direction perpendicular to the optical axis of the lens, and a plurality of protrusions are formed at a predetermined interval on the outer peripheral portion;
Has an annular shape surrounding the respective projections, peaks and valleys in the inner peripheral portion are alternately formed, the valley and the projection is orthogonal to the optical axis of the lens holding frame to face It is possible to rotate between an unlock position that allows movement in a direction and a lock position that restricts movement of the lens holding frame in a direction perpendicular to the optical axis so that the protrusion and the peak face each other. A locking member supported by the fixed frame;
A drive gear that meshes with a gear portion provided on an outer peripheral portion of the lock member and rotates the lock member between the unlock position and the lock position via the gear portion ;
A first rotation limiting member that receives the lock member so as to limit rotation of the lock member in a first rotation direction at the unlock position ;
A second rotation limiting member for receiving the lock member so as to limit rotation of the lock member in a second rotation direction opposite to the first rotation direction at the lock position ;
Of the reaction force that the lock member receives from the first rotation limiting member when the lock member comes into contact with the first rotation limiting member, the rotation center of the drive gear and the rotation center of the lock member are Of the component force in the connecting direction and the reaction force received by the lock member from the second rotation limiting member when the lock member contacts the second rotation limiting member, the rotation center of the drive gear and the A lens barrel characterized in that the component force in the direction connecting the rotation center of the lock member is substantially equal . The position where the lock member contacts the first rotation limiting member and the position where the lock member contacts the second rotation limiting member connect the rotation center of the drive gear and the rotation center of the lock member. The lens barrel according to claim 1 , wherein the lens barrel is substantially symmetrical with respect to a straight line . The lens barrel according to claim 1 or 2, wherein the first and the rotation limiting member and the second rotation restricting member is equal to or is integral. The lens barrel according to any one of claims 1 to 3, wherein the first rotation limiting member and the second rotation limiting member are elastic members. A motor for rotating the drive gear;
The rotation stopping and holding force in the non-excited state of the motor, the first locking member in any one of claims 1 to 4, wherein the holding at the respective positions of the lock position and the unlock position The lens barrel described. A camera comprising: the lens barrel according to any one of claims 1 to 5; and a camera body to which the lens barrel is mounted.

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