JP2013125127A - Lens drive mechanism, lens barrel, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve simplification and low cost of a lens driving mechanism in which a manual focus operation is interruptible during autofocus operation, and to provide a lens barrel and the like using the lens driving mechanism.SOLUTION: Employed are a lens driving mechanism and the like in which: a speed reduction mechanism includes a combination of a first step angular bearing and a second step angular bearing mounted to a driving force input shaft unit; during autofocus operation, driving force is transmitted from a driving source to the driving force input shaft unit, and a driving force output shaft unit is rotated through an inner ring of the second step angular bearing to output lens driving force; and during manual focus operation, driving force transmitted by a photographer is transmitted to an outer ring of the second step angular bearing, and at this time the driving force output shaft unit is rotated through the outer ring to output lens driving force.

Description

  The present invention relates to a lens driving mechanism, a lens barrel, and an imaging apparatus. Specifically, a manual focus operation manually performed by a photographer can be interrupted during an autofocus operation performed using a driving force of a driving source. The present invention relates to a lens driving mechanism, a lens barrel, and an imaging device.

  Conventionally, in a focus adjustment of a lens system in a video camera or a still camera, a manual operation by a photographer manually and an autofocus operation by a driving force of a driving source are provided by a switching operation member provided outside the camera or the lens. There is a lens drive mechanism that is operated and switched. However, in a camera equipped with such a lens drive mechanism, if the photographer wants to fine-tune the focus manually after focusing with autofocus, the start of manual focus operation is delayed or a switching operation is performed. In order to do this, the eyes had to be taken off from the photographic image of the viewfinder or the like, and it was difficult to shoot at the target timing. Therefore, there has been a demand for a camera having a lens drive mechanism that can switch between an autofocus operation and a manual focus operation without a troublesome switching operation.

  For example, Patent Document 1 discloses a lens barrel that can operate a lens such as a focus lens substantially continuously without requiring a special switching operation for two inputs. Specifically, in the lens barrel of Patent Document 1, when the motor driving device drives the motor as a rod-shaped ultrasonic motor, for example, during autofocus operation, the shaft output member rotates and the ball member rotates by friction. While rotating around the shaft output member, the rotation output member is rotated. Further, when the external input member is rotated during the manual focus operation, similarly, the ball member revolves around the shaft output member while rotating frictionally to rotate the rotation output member.

Japanese Patent No. 3347344

  However, the lens barrel motor driving device described in Patent Document 1 does not need to be operated by providing a switching operation member outside the camera or the lens when switching between the autofocus operation and the manual focus operation. When the driving force by the manual focus operation is transmitted, the motor must have such a shaft holding force that the shaft output member does not rotate (see paragraph 0022). Therefore, the motor driving device described in Patent Document 1 has a structure that restricts the rotation of the output rotation shaft of the motor used in both the forward and reverse directions during the manual focus operation, and is based on the manual focus operation. The motor must be provided with a structure that does not cause damage due to transmission of the driving force, resulting in a complicated structure. Further, in Patent Document 1, an ultrasonic motor is cited as a motor used in a motor driving device. However, the ultrasonic motor has a problem in terms of cost in addition to a complicated structure.

  The present invention has been made in view of such a conventional problem, and it is possible to interrupt a manual focus operation manually performed by a photographer during an autofocus operation performed using the driving force of a driving source, but with a structure. It is an object of the present invention to provide a lens driving mechanism capable of simplifying and reducing the cost, and a lens barrel and an imaging apparatus using the lens driving mechanism.

  Accordingly, as a result of earnest research, the present inventors have adopted the following lens driving mechanism, and a lens barrel and an imaging apparatus using the lens driving mechanism in order to solve the above-described problems.

Lens drive mechanism according to the present invention: The lens drive mechanism according to the present invention is a drive source for performing focus adjustment by sliding the focus lens housed in the lens barrel through the lens holding frame in the optical axis direction. A reduction mechanism used for a lens drive mechanism capable of interrupting a manual focus operation manually performed by a photographer during an autofocus operation using the driving force of the first and second deceleration bearings and the second angular bearing. Including a combination with a step angular bearing, the first step angular bearing penetrates and fixes one end side of the driving force input shaft portion inside the inner ring, and the second step angular bearing is located inside the inner ring. A retainer that penetrates and fixes the other end of the driving force input shaft portion and rotatably supports the provided ball is arranged so as to be able to rotate synchronously with the second stage angular bearing. The driving force is coupled to one end of the driving force output shaft portion, and during the autofocus operation, the driving force from the driving source is transmitted to the driving force input shaft portion, and the driving force input shaft portion is connected to the driving force input shaft portion at this time. The driving force output shaft portion rotates in synchronization with the ball rotating through the inner ring of the two-stage angular bearing, and the lens driving force is output from the other end side of the driving force output shaft portion. The driving force transmitted by the photographer is transmitted to the outer ring of the second-stage angular bearing. At this time, the driving force output shaft portion rotates in synchronization with the ball rotating through the outer ring, and the driving The lens driving force is output from the other end side of the force output shaft portion.

  The lens driving mechanism of the present invention uses the driving force of the driving source when performing focus adjustment by sliding the focus lens housed in the lens barrel through the lens holding frame in the optical axis direction. A lens drive mechanism that can interrupt manual focus operation manually performed by the photographer during autofocus operation. The lens drive mechanism is inserted into the fixed cylinder and the outer periphery of the fixed cylinder and rotates itself. A cam cylinder that moves the lens holding frame in the optical axis direction, and a speed reduction mechanism that transmits the driving force from the driving source to the cam cylinder, and the speed reduction mechanism receives the driving force from the driving source. A driving force input shaft portion having a driving force input portion for receiving autofocus, and one end side of the driving force input shaft portion penetrates and is fixed inside the inner ring, and an outer ring that fixes the inner ring and the ball is fixed. A first-stage angular bearing, an inner ring to which the other end side of the driving force input shaft portion is inserted and fixed inside the inner ring to transmit the driving force for autofocus, the inner ring and the ball are sandwiched, and the photographer's A second-stage angular bearing having an outer ring to which a driving force for manual focusing is transmitted, and an outer ring of the second-stage angular bearing are provided, and a driving force input section for manual focusing is provided. An angular bearing pressing ring, and an outer ring of the first-stage angular bearing directly or indirectly fixed, and arranged in a state of frictional contact with the angular bearing pressing ring, and the driving force input shaft portion, A bearing case housing the first-stage angular bearing and the second-stage angular bearing, and a rotational drive transmitted from the second-stage angular bearing Driving force output shaft portion coupled to a retainer for rotatably supporting the ball of the second stage angular bearing so as to be able to rotate synchronously on the rotation shaft of the second stage angular bearing. In the autofocus operation, the driving force from the driving source transmitted to the driving force input shaft portion is transmitted to the inner ring of the second-stage angular bearing. At this time, the angular bearing holding ring and the bearing The coupling state by the frictional force with the case is maintained, and the driving force output shaft rotates synchronously with the inner ring of the second-stage angular bearing, so that the lens holding frame is slid to adjust the focus, and the manual focus operation Sometimes, the driving force transmitted by the photographer's operation is transmitted to the manual focus driving force input part of the angular bearing retainer ring, At this time, the driving force transmitted by the photographer's operation releases the coupling state by the frictional force between the angular bearing holding ring and the bearing case, and the driving force output shaft portion is connected to the outer ring of the second-stage angular bearing. It is preferable to perform focus adjustment by sliding the lens holding frame by synchronous rotation.

  In the lens driving mechanism according to the present invention, the lens driving mechanism is such that the driving source is a DC motor, and the speed reduction mechanism fixes the worm gear to the output rotation shaft of the DC motor, and the worm gear and the worm wheel gear. It is preferable to include the meshing structure.

  In the lens driving mechanism according to the present invention, in the lens driving mechanism, the driving force input shaft portion has a worm wheel gear that meshes with a worm gear fixed to the output rotation shaft of the DC motor at a predetermined position on the outer periphery thereof. The first-stage angular bearing is configured such that a ball is clamped by pressing an outer ring on one end side toward the other end side and an inner ring on the other end side toward one end side by an elastic member, and driving force is input by the inner ring. The shaft portion is rotatably supported, and the second-stage angular bearing is configured such that an elastic member presses the outer ring on one end side toward the other end side and the inner ring on the other end side toward the one end side to hold the ball. The outer ring is frictionally coupled to the bearing case via the angular bearing retainer ring, and the frictional coupling force between the angular bearing retainer ring and the bearing case is applied to the lens driving mechanism. When the frictional coupling force is greater than the set frictional coupling force, the coupling state between the angular bearing retainer ring and the bearing case is maintained and the autofocus operation is performed normally, and the friction between the angular bearing retainer ring and the bearing case is normal. When the coupling force is smaller than the frictional coupling force set in the lens driving mechanism, it is preferable that the outer ring of the second stage angular bearing rotates and the manual focus operation is performed normally.

  Further, in the lens driving mechanism according to the present invention, the speed reduction mechanism further includes an angular bearing pressing member that supports the first-stage angular bearing, and the angular bearing pressing member can adjust the elasticity of the elastic member. It is preferable that the bearing case is fixed so as to be movable.

  In the lens driving mechanism according to the present invention, the elastic member is preferably a disc spring.

  In the lens driving mechanism according to the present invention, it is preferable that torque oil is applied to the sliding surfaces of the balls of the first-stage angular bearing and the second-stage angular bearing.

  In the lens driving mechanism according to the present invention, the lens driving mechanism is engaged with a gear fixed to the driving force output shaft portion and rotates around the optical axis, and one end side is coupled to the focus gearing. An arm member coupled to the protrusion provided on the outer periphery of the cam cylinder, and a gear fixed to the driving force output shaft when the focus lens is slid in the optical axis direction. It is preferable to slide the lens holding frame by rotating the cam cylinder with the driving force transmitted from the focus gear ring and the arm member.

  In the lens driving mechanism according to the present invention, the lens driving mechanism is configured such that a manual focus ring is fitted to the outer periphery of the lens barrel, and one end side is fitted to the inner circumference of the manual focus ring, and the other end side is A manual focus driving force input section provided on the outer ring of the second-stage angular bearing and a manual focus ring gear meshed with each other and coupled to each other. The manual focus ring is rotated during manual focus operation by the photographer. It is preferable to adjust the focus by sliding the lens holding frame by moving it.

Lens barrel according to the present invention: The lens barrel of the present invention is characterized by using the lens driving mechanism described above.

Imaging Device According to Present Invention: The imaging device according to the present invention is characterized by using the lens barrel described above.

  The lens driving mechanism according to the present invention is capable of interrupting a manual focus operation manually performed by a photographer during an autofocus operation performed using a driving force of a driving source, but simplifies the structure and reduces costs. I can plan. Therefore, the lens driving mechanism of the present invention can be suitably used for various types of imaging devices.

It is a schematic cross section which shows the lens drive mechanism which concerns on one Embodiment of this invention. It is the figure which illustrated arrangement | positioning in the lens-barrel of the lens drive mechanism shown in FIG. 1 seeing from the image surface side. FIG. 2 is a development relationship diagram of a cam cylinder in the lens driving mechanism shown in FIG. 1. It is sectional drawing cut | disconnected and shown by the surface which passes along the output drive shaft of the lens drive mechanism shown in FIG. FIG. 2 is a cross-sectional view of a surface that is perpendicular to the output drive shaft of the lens drive mechanism shown in FIG. 1 and passes through the motor output shaft. FIG. 2 is a cross-sectional view of a plane that is perpendicular to the output drive axis of the lens drive mechanism shown in FIG. 1 and passes through the center of the angular ball.

  Hereinafter, embodiments of the lens driving mechanism according to the present invention will be described with reference to the drawings. In the drawings shown below, the lenses other than the focus lens and members related thereto are omitted for easy viewing. FIG. 1 is a schematic sectional view showing a lens driving mechanism according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the arrangement of the lens driving mechanism shown in FIG. 1 in the lens barrel as viewed from the image plane side. FIG. 3 is a development relationship diagram of the cam cylinder in the lens driving mechanism shown in FIG. 4 is a cross-sectional view taken along a plane passing through the output drive shaft of the lens drive mechanism shown in FIG. FIG. 5 is a cross-sectional view of a plane perpendicular to the output drive shaft of the lens drive mechanism shown in FIG. 1 and passing through the motor output shaft. FIG. 6 is a cross-sectional view of a plane perpendicular to the output drive axis of the lens drive mechanism shown in FIG. 1 and passing through the center of the angular ball.

Lens Drive Mechanism According to the Present Invention: The lens drive mechanism A according to the present invention performs focus adjustment by sliding the focus lens L accommodated in the lens barrel 12 via the lens holding frame 7 in the direction of the optical axis O. When performing, a decelerating mechanism capable of interrupting a manual focus operation manually performed by a photographer during an autofocus operation performed using a driving force of a driving source is provided. This speed reduction mechanism includes a combination of a first stage angular bearing 21 and a second stage angular bearing 23. Here, the said 1st step | paragraph angular bearing 21 penetrates and fixes the one end side of the driving force input shaft part 22 inside the inner ring | wheel 21a. Further, the second-stage angular bearing 23 has a retainer 23c that penetrates and fixes the other end side of the driving force input shaft portion 22 inside the inner ring 23a and rotatably supports the provided ball 23d. The two-stage angular bearing 23 is coupled to one end side of a driving force output shaft portion 30 that is arranged to be able to rotate synchronously. During the autofocus operation, the driving force from the driving source 26 is transmitted to the driving force input shaft portion 22, and the inner ring 23 a of the second-stage angular bearing 23 connected to the driving force input shaft portion 22 at this time. The driving force output shaft portion 30 rotates in synchronization with the ball 23d rotating through the lens, and the lens driving force is output from the other end side of the driving force output shaft portion 30. Further, during the manual focus operation, the driving force transmitted by the photographer is transmitted to the outer ring 23b of the second stage angular bearing 23, and at this time, the driving is performed in synchronization with the ball 23d rotating through the outer ring 23b. The force output shaft portion 30 rotates to output a lens driving force from the other end side of the driving force output shaft portion 30.

  As described above, the lens driving mechanism A according to the present invention performs the focus adjustment by sliding the focus lens L accommodated in the lens barrel 12 via the lens holding frame 7 in the direction of the optical axis O. This is a lens driving mechanism capable of interrupting a manual focus operation manually performed by a photographer during an autofocus operation performed using the driving force of the drive source 26. The lens driving mechanism A according to the present invention includes a fixed cylinder 5 and a cam cylinder 1 that is inserted through the outer periphery of the fixed cylinder 5 and moves the lens holding frame 7 in the optical axis O direction by its own rotation. As a speed reduction mechanism for transmitting the driving force from the driving source 26 to the cam cylinder 1, a combination of the first-stage angular bearing 21 and the second-stage thrust roller bearing 23 is provided to transmit the driving force. Loss is unlikely to occur. Hereinafter, the lens driving mechanism A according to the present invention will be described more specifically and in detail.

  As shown in FIG. 1, the lens holding frame 7 is a lens frame having a focus lens L. Three convex portions 8 are provided on the outer periphery of the lens holding frame 7 so as to be arranged at 120 degrees, and a cam roller 8 a is provided on the convex portion 8. It is inserted, passes through the straight cam groove hole 5 a of the fixed cylinder 5 and the cam groove hole 1 b of the cam cylinder 1, and is held at the inner diameter of the fixed cylinder 5. Further, the fixed cylinder 5 is provided with a convex portion 6 on the outer periphery thereof, a cam roller 6a inserted into the convex portion 6 is engaged with the cam groove hole 1a of the cam cylinder 1, and the cam cylinder 1 is connected to the cam cylinder 1. It rotates at a fixed position with respect to the optical axis O direction within the range of the slot 1a. When the cam cylinder 1 rotates at a fixed position in response to the rotational force from the outer peripheral projection 2, the convex portion 8 on the outer periphery of the lens holding frame 7 follows the cam groove 1b (see FIG. 2). The lens holding frame 7 slides in the direction of the optical axis O. The lens driving mechanism A according to the present invention is fixedly attached to the fixed barrel 11 of the lens barrel 12.

  In the lens driving mechanism A according to the present invention, the reduction mechanism provided is a driving force input shaft portion 22, a first stage angular bearing 21, a second stage angular bearing 23, an angular bearing pressing ring 33, and a bearing case. 34 and the driving force output shaft portion 30 are included. As described above, the lens driving mechanism A according to the present invention uses the first-stage angular bearing 21 and the second-stage angular bearing 23 in combination to shorten the width of the driving force output shaft portion 30 in the radial direction. I can do it. Further, the lens driving mechanism A according to the present invention includes a speed reduction mechanism by meshing a worm wheel gear 24 provided on the outer periphery of the driving force input shaft portion 22 and a worm gear 25 fixed to the output rotation shaft 27 of the DC motor 26. By providing the speed reduction mechanism by the planetary roller deceleration of the second stage angular bearing 23, it is possible to improve the quietness compared to the conventional gear train.

  Here, the driving force input shaft portion 22 provided in the lens driving mechanism A according to the present invention includes an autofocus driving force input portion 24 that receives the driving force from the driving source 26. Therefore, the driving force input shaft portion 22 of the present invention is rotated by the driving force from the driving source 26 being transmitted to the outer periphery.

  Further, in the first stage angular bearing 21 provided in the lens driving mechanism A according to the present invention, one end side of the driving force input shaft portion 22 penetrates inside the inner ring 21a that holds the ball 21d with the outer ring 21b. It is fixed. Incidentally, the balls 21d are held at equal intervals by the retainer 21c (see FIG. 6). That is, the first stage angular bearing 21 used in the lens driving mechanism A of the present invention has a so-called angular structure in which a straight line connecting the contacts of the inner ring 21a, the ball 21d and the outer ring 21b has an angle (contact angle) with respect to the radial direction. It is a ball bearing. Therefore, in the angular bearing 21 of the present invention, the driving force from the driving source 26 is transmitted to the inner ring 21 a via the driving force input shaft portion 22, and the inner ring 21 a is synchronized with the driving force input shaft portion 22. It can be rotated.

  Further, the second-stage angular bearing 23 provided in the lens driving mechanism A according to the present invention has the other end side of the driving force input shaft portion 22 penetrating inside the inner ring 23a that holds the ball 23d with the outer ring 23b. Is fixed. The balls 23d are held at regular intervals by the retainer 23c (see FIG. 6). That is, the second-stage angular bearing 23 used in the lens driving mechanism A of the present invention is similar to the first-stage angular bearing 21 in that the straight line connecting the contacts of the inner ring 23a, the ball 23d and the outer ring 23b is at an angle with respect to the radial direction. This is a so-called angular contact ball bearing having a (contact angle). In the second-stage angular bearing 23 of the present invention, the autofocus driving force is transmitted to the inner ring 23a, and the manual focus driving force by the photographer's operation is transmitted to the outer ring 23b. As a result, the lens driving mechanism A according to the present invention transmits the autofocus driving force when the inner ring 23a rotates, and transmits the manual focus driving force when the outer ring 23b rotates.

  Further, the angular bearing pressing ring 33 of the present invention is fixed to the outer ring 23b of the second-stage angular bearing 23, and a manual focus driving force input section 35 is provided. The angular bearing retainer ring 33 is fixed to the outer ring 23b of the second stage angular bearing 23, and when the manual focus driving force is transmitted from the manual focus driving force input section 35, the second stage angular bearing 23 has a The ball 23d and the retainer 23c rotate in synchronization with the outer ring 23b.

  The bearing case 34 of the present invention accommodates the driving force input shaft portion 22, the first stage angular bearing 21, and the second stage angular bearing 23. The bearing case 34 of the present invention is arranged in a state in which the outer ring 21b of the first-stage angular bearing 21 is fixed directly or indirectly and in frictional contact with the angular bearing holding ring 33. Here, in the case where the outer ring 21b of the first-stage angular bearing is fixed to the bearing case 34, a method such as press-fitting or bonding to the bearing case 34 can be employed when directly fixing the outer ring 21b. For example, a method of interposing the elastic member 20b between the bearing case 34 and the outer ring 21b can be employed. Therefore, in the lens driving mechanism A of the present invention, only the inner ring 21a can be rotated at the first stage angular bearing 21, and the inner ring 23a or the outer ring 23b can be rotated at the second stage angular bearing 23.

  Further, the driving force output shaft portion 30 of the present invention rotatably supports the ball 23d of the second stage angular bearing 23 in order to transmit the rotational driving force transmitted from the second stage angular bearing 23 to the cam cylinder 1. It is coupled to one end of the retainer 23c to be fixed on the rotating shaft of the second stage angular bearing so as to be able to rotate synchronously. That is, the driving force output shaft portion 30 of the present invention is rotated in synchronization with the ball 23d of the second stage angular bearing 23. At this time, the driving force output shaft portion 30 is pivotally supported by the angular bearing holding ring 33 (part 33a in FIG. 4), so that the driving force output shaft portion 30 can be rotated in a stable state. It becomes possible.

  In the lens driving mechanism A according to the present invention, during the autofocus operation, the driving force transmitted from the driving source 26 transmitted to the driving force input shaft portion 22 is transmitted to the inner ring 23a of the second stage angular bearing 23, At this time, the coupling state by the frictional force between the angular bearing pressing ring 33 fixed to the outer ring 23b of the second stage angular bearing 23 and the bearing case 34 is maintained, and the driving force output shaft portion 30 is By rotating synchronously with the inner ring 23a of the second-stage angular bearing, the lens holding frame 7 is slid to adjust the focus. Further, in the lens driving mechanism A according to the present invention, during the manual focus operation, the driving force transmitted by the photographer's operation is transmitted to the manual focusing driving force input portion 35 of the angular bearing press ring 33, and this Sometimes, the driving force transmitted by the photographer's operation releases the coupling state by the frictional force between the angular bearing retainer ring 33 fixed to the outer ring 23b of the second stage angular bearing 23 and the bearing case 34, and The driving force output shaft portion 30 rotates synchronously with the outer ring 23b of the second-stage angular bearing so that the lens holding frame 7 is slid to perform focus adjustment.

  As described above, the lens driving mechanism A according to the present invention employs a combination of the angular bearings 21 and 23, which are general-purpose products, so that maintenance can be facilitated and product cost can be reduced. . In addition, as described above, the lens driving mechanism A according to the present invention maintains the coupled state by the frictional force between the angular bearing holding ring 33 fixed to the outer ring 23b of the second angular bearing 23 and the bearing case 34. Alternatively, switching between the autofocus operation and the manual focus operation is performed by canceling, so that the driving force by the manual focus operation is transmitted only to the focus lens, and the lens can be driven safely. In addition, according to the lens driving mechanism A according to the present invention, it is possible to prevent the parts that drive the focus lens from being damaged due to an excessive load.

  Further, in the lens driving mechanism A according to the present invention, the driving source 26 is a DC motor, the reduction mechanism fixes the worm gear 25 to the output rotation shaft 27 of the DC motor, and the worm gear 25 and the worm wheel gear 24 are engaged. It preferably includes a mating structure.

  The lens driving mechanism A according to the present invention employs a structure in which the worm gear 25 is fixed to the output rotation shaft 27 of the DC motor 26 and meshed with the worm wheel gear 24, so that the worm gear 25 and the worm wheel gear 24 can be connected to each other. By setting the self-locking condition, even if a force against the rotational force of the output rotating shaft 27 of the DC motor 26 is transmitted to the worm wheel gear 24, a reverse driving force is transmitted to the output rotating shaft 27. Therefore, damage to the DC motor 26 can be prevented. As shown in FIGS. 5 and 6, the DC motor 26 is screwed and fixed to the motor mounting surface 20a of the motor mounting plate 28, and the motor mounting plate 28 and the case 20 are screwed to form a lens. The drive mechanism A is attached at a predetermined position. As shown in FIGS. 4 to 6, the case 20 is press-fitted with a bearing case 34 containing a reduction mechanism such as a first-stage angular bearing 21 and a second-stage angular bearing 23, and the worm wheel. The gear 24 and the worm gear 25 are also accommodated.

  The lens driving mechanism A according to the present invention preferably has a structure in which a worm wheel gear 24 that meshes with a worm gear 25 fixed to an output rotation shaft 27 of the DC motor 26 is provided on the outer periphery of the driving force input shaft portion 22. . As described above, the lens driving mechanism A according to the present invention includes the worm wheel gear 24 provided on the outer periphery of the driving force input shaft portion 22 and meshes with the worm gear 25 fixed to the output rotation shaft 27 of the DC motor 26. The self-lock function necessary for the present invention can be established and a large reduction ratio can be obtained. Further, according to the lens driving mechanism A according to the present invention, it is possible to reduce the size of the lens driving mechanism and reduce noise during driving by adopting friction driving by a planetary roller. As shown in FIG. 4, the worm wheel gear 24 is provided at a position between the positions where the first-stage angular bearing 21 and the second-stage angular bearing 23 are arranged in the driving force input shaft portion 22. Thus, the rotational behavior of the driving force input shaft portion 22 can be further stabilized.

  In the lens driving mechanism A according to the present invention, the first-stage angular bearing 21 is pressed by the elastic member 29 so that the outer ring 21b on one end side is directed toward the other end side and the inner ring 21a on the other end side is pressed toward the one end side. Thus, the ball 21d is clamped. Further, with respect to the second-stage angular bearing 23, the elastic member 29 presses the outer ring 23b on one end side toward the other end side and the inner ring 23a on the other end side toward the one end side, thereby holding the ball 23d. As described above, the lens driving mechanism A according to the present invention is provided with the elastic member 29, so that the contact force at the time of rolling of the balls 21d and 23d in the first-stage angular bearing 21 and the second-stage angular bearing 23 is increased. The driving force transmitted to the second stage angular bearing 23 can be transmitted to the output side without loss. And the said 1st step | paragraph angular bearing 21 supports the driving force input shaft part 22 so that rotation is possible by the inner ring | wheel 21a. The driving force input shaft portion 22 is supported by the first angular bearing 21 at one end side, so that the driving force input shaft portion 22 can be stably rotated. Further, the second-stage angular bearing 23 has its outer ring 23 b frictionally coupled to the bearing case 34 via an angular bearing holding ring 33.

  By providing the structure shown above, the lens driving mechanism A of the present invention is configured such that the frictional coupling force between the angular bearing pressing ring 33 and the bearing case 34 fixed to the outer ring 23b of the second-stage angular bearing is the lens driving. When it is larger than the frictional coupling force set in the mechanism A, the angular bearing holding ring 33 and the bearing case 34 are maintained in a coupled state, and the autofocus operation can be performed normally. At this time, the ball 23d rotates together with the inner ring 23a of the second stage angular bearing, and the driving force output shaft portion 30 coupled to the retainer 23c that supports the ball 23d rotates synchronously with the inner ring 23a. Further, the lens driving mechanism A of the present invention is a friction in which the frictional coupling force between the angular bearing holding ring 33 fixed to the outer ring 23b of the second stage angular bearing and the bearing case 34 is set in the lens driving mechanism. When the coupling force is smaller, the outer ring 23b of the second stage angular bearing rotates and the manual focus operation can be performed normally. At this time, the ball 23d rotates together with the outer ring 23b of the second-stage angular bearing, and the driving force output shaft portion 30 coupled to the retainer 23c that supports the ball 23d rotates synchronously with the outer ring 23b.

  Thus, the lens driving mechanism A of the present invention uses the friction force acting between the angular bearing retainer ring 33 fixed to the outer ring 23b of the second-stage angular bearing and the bearing case 34 to Even during the focus operation, the focus lens L can be manually focused substantially continuously without any special switching operation. Further, in the lens driving mechanism A according to the present invention, the transmission of the driving force outside the allowable range by the manual focus operation is not transmitted to the DC motor 26 serving as a driving source. Therefore, the lens driving mechanism A according to the present invention does not increase the number of parts such as using dedicated parts separately so that an excessive driving force is not transmitted to the motor, and reduces the size and weight when used in an imaging apparatus. Can do.

  Further, in the lens driving mechanism A according to the present invention, the speed reduction mechanism can further include an angular bearing pressing member 32 that supports the first stage angular bearing 21. By using the angular bearing pressing member 32, the first stage angular bearing 21 can be supported more stably, and the rotation of the ball 21d of the first stage angular bearing can be further stabilized. And the angular bearing pressing member 32 can adjust the elasticity of the elastic member 29 for pressing the outer rings 21b, 23b of the first and second angular bearings by moving the fixed position. Is preferred. For example, when a part of the inner peripheral surface of the bearing case 34 is threaded and a part of the outer peripheral surface of the angular bearing holding member 32 is screwed so as to be screwable with the bearing case 34, The elasticity of the elastic member 29 can be adjusted by adjusting the tightening amount of the angular bearing holding member 32. Therefore, the lens driving mechanism A according to the present invention uses the angular bearing holding member 32, so that the balls 21d and 23d of the first-stage angular bearing 21 and the second-stage angular bearing 23 are not affected by the type of the elastic member 29. It becomes easy to appropriately correct the contact force during rolling.

  In the lens driving mechanism A according to the present invention, the elastic member 29 is preferably a disc spring.

  The lens drive mechanism A according to the present invention employs a disc spring as the elastic member 29, so that it is possible to reliably press only the inner rings 21a, 23a or only the outer rings 21b, 23b of the angular bearings 21, 23. Become. As the elastic member 29, a rubber O-ring or the like can be suitably used in addition to the disc spring. Incidentally, in FIG. 4, a disc spring is used as the elastic member 29, the outer ring 21 b on one end side of the first step angular bearing 21 is pressed toward the other end side, and the other end side of the first step angular bearing 21. The structure in which the inner ring 21a is pressed toward one end side by a ring 36 inserted with the driving force input shaft portion 22 as the same axis is shown.

  In the lens drive mechanism A according to the present invention, it is preferable that torque oil is applied to the sliding surfaces of the balls 21d and 23d of the first-stage angular bearing 21 and the second-stage angular bearing 23.

  The first-stage angular bearing 21 and the second-stage angular bearing 23 used in the lens driving mechanism A according to the present invention rotate in a state where the balls 21d, 23d are in frictional contact between the inner rings 21a, 23a and the outer rings 21b, 23b. While revolving around the driving force input shaft portion 22. Therefore, the first-stage angular bearing 21 and the second-stage angular bearing 23 smoothly perform the autofocus operation and the manual focus operation over a long period of time unless torque oil is applied to the sliding surfaces of the balls 21d, 23d. It becomes difficult to do. By enclosing the torque oil, the rolling bearing can transmit the driving force from the driving source to the cam cylinder 1 more efficiently without losing the function, and the durability of the lens driving mechanism A can be improved. It becomes possible. Further, as the torque oil used in the present invention, an appropriate one can be used based on conditions such as the temperature, rotational speed and load of the rolling bearing.

  In addition, the lens driving mechanism A according to the present invention includes a focus gear ring 3 that meshes with a gear 31 fixed to the driving force output shaft portion 30 and rotates around the optical axis, and one end side coupled to the focus gear ring 3 and the other end. The arm member 4 can be provided with a side coupled to a protrusion 2 provided on the outer periphery of the cam cylinder 1. When the focus lens L is slid in the optical axis O direction, the driving force transmitted from the gear 31 fixed to the driving force output shaft portion 30 is transmitted via the focus gear ring 3 and the arm member 4. It is preferable to slide the lens holding frame 7 by rotating the cam cylinder 1.

  The lens driving mechanism A according to the present invention can set the shape of the arm member 4 according to the shape of the lens barrel 12 used, the arrangement of each component in the lens barrel 12, and the like. It can be applied to the device. As shown in FIG. 2, the arm member 4 has a U-shaped tip, and the U-shaped portion can sandwich the protrusion 2 provided on the outer periphery of the cam cylinder 1.

  In the lens driving mechanism A according to the present invention, the manual focus ring 9 is fitted to the outer periphery of the lens barrel 12, and the one end side 10a is fitted to the inner circumference of the manual focus ring 9, and the other end side is the angular contact. The manual focus driving force input portion 35 provided on the bearing retainer ring 33 can be provided with a manual focus ring gear 10 that is meshed and coupled with each other. The lens driving mechanism A according to the present invention can adjust the focus by sliding the lens holding frame by rotating the manual focus ring 9 during the manual focus operation by the photographer. preferable.

  The lens driving mechanism A according to the present invention can interrupt the manual focus operation during the autofocus operation by a simple operation of simply rotating the manual focus ring 9 provided on the outer periphery of the lens barrel 12. I can do it. Therefore, according to the lens driving mechanism A according to the present invention, the manual focus operation can be quickly started, and the photographing at the target timing can be performed without taking the eyes off the photographed image of the finder or the like for performing the switching operation. It becomes. As shown in FIG. 4, the gear of the manual focus driving force input portion 35 can be provided by causing the end portion of the angular bearing holding ring 33 to protrude from the bearing case 34 and to be fixed to the protruding portion.

Lens barrel according to the present invention: The lens barrel 12 according to the present invention uses the above-described lens driving mechanism A according to the present invention.

  According to the lens barrel 12 according to the present invention, by using the lens driving mechanism A according to the present invention described above, even during the autofocus operation, it is substantially continuous without any special switching operation. In addition, the focus lens L can be manually focused, and a high-quality autofocus lens barrel can be provided at low cost.

Imaging device according to the present invention: The imaging device according to the present invention uses the lens barrel 12 according to the present invention described above.

  According to the imaging apparatus (not shown) according to the present invention, by using the above-described lens barrel 12 according to the present invention, it is possible to reduce the size, the lens movement accuracy is excellent, and the quietness is excellent. Can be provided.

  According to the lens drive mechanism of the present invention, the drive source is not limited to an expensive ultrasonic motor, and a relatively inexpensive DC motor can be used as it is. In addition, the lens drive mechanism according to the present invention is configured such that the motor output shaft of the drive source and the reduction gear unit output gear shaft are orthogonal to each other, so that the entire drive unit can be shortened, and the total length of the lens can be reduced. There is no restriction on the position in the optical axis direction. In particular, since the lens driving mechanism according to the present invention combines angular bearings with short radial widths, the outer diameter of the lens barrel can be reduced. As described above, the lens driving mechanism according to the present invention can be suitably used for any lens barrel and imaging device.

DESCRIPTION OF SYMBOLS 1 Cam cylinder 2 Protrusion part 3 Focus gear ring 4 Arm member 5 Fixed cylinder 6 Convex part 7 Lens holding frame 8 Convex part 9 Manual focus ring 10 Manual focus ring gear 11 Fixed lens barrel 12 Lens barrel 20 Case 20a Motor mounting surface 20b Elastic member 21 First stage angular bearing 21a Inner ring 21b Outer ring 21c Retainer 21d Ball 22 Driving force input shaft 23 Second stage angular bearing 23a Inner ring 23b Outer ring 23c Retainer 23d Ball 24 Autofocus driving force input part (worm wheel gear)
25 Worm gear 26 Drive source (DC motor)
27 Output Rotating Shaft 29 Elastic Member 30 Driving Force Output Shaft Part 31 Gear 32 Angular Bearing Pressing Member 33 Angular Bearing Pressing Ring 34 Bearing Case 35 Manual Focusing Driving Force Input Part (Gear)
A Lens drive mechanism L Focus lens O Optical axis Y Drive force output shaft 30 axis

Claims (11)

When performing the focus adjustment by sliding the focus lens housed in the lens barrel through the lens holding frame in the optical axis direction, the photographer manually operates during the autofocus operation using the driving force of the drive source. A deceleration mechanism used for a lens drive mechanism capable of interrupting manual focus operation performed in
The speed reduction mechanism includes a combination of a first stage angular bearing and a second stage angular bearing,
The first stage angular bearing is fixed by penetrating one end side of the driving force input shaft portion inside the inner ring,
The second-stage angular bearing rotates in synchronism with the second-stage angular bearing, and the retainer that rotatably supports the provided ball is inserted into and fixed to the inner ring of the other end of the driving force input shaft. It is coupled to one end of the driving force output shaft that can be arranged,
During the autofocus operation, the driving force from the driving source is transmitted to the driving force input shaft portion, and at this time, a ball that rotates through the inner ring of the second-stage angular bearing connected to the driving force input shaft portion The driving force output shaft portion rotates synchronously, and the lens driving force is output from the other end side of the driving force output shaft portion,
During manual focus operation, the driving force transmitted by the photographer is transmitted to the outer ring of the second-stage angular bearing, and at this time, the driving force output shaft portion rotates in synchronization with the ball rotating through the outer ring. A lens driving mechanism that outputs a lens driving force from the other end side of the driving force output shaft portion. When performing the focus adjustment by sliding the focus lens housed in the lens barrel through the lens holding frame in the optical axis direction, the photographer manually operates during the autofocus operation using the driving force of the drive source. A lens drive mechanism that can interrupt manual focus operation performed in
The lens driving mechanism includes a fixed cylinder, a cam cylinder that is inserted through the outer periphery of the fixed cylinder and moves the lens holding frame in the optical axis direction by its own rotation, and a driving source for the cam cylinder. And a speed reduction mechanism that transmits the driving force of
A driving force input shaft portion provided with a driving force input portion for autofocus that receives the driving force from the driving source;
A first-stage angular bearing in which one end side of the driving force input shaft portion is inserted and fixed inside the inner ring, and the outer ring holding the inner ring and the ball is fixed;
The other end of the driving force input shaft portion is inserted and fixed inside the inner ring, and the inner ring to which the driving force for autofocus is transmitted, the inner ring and the ball are sandwiched, and the driving force by the photographer is transmitted. A second stage angular bearing having an outer ring to which a manual focus driving force is transmitted;
An angular bearing retainer ring fixed to the outer ring of the second stage angular bearing and provided with a manual focus driving force input;
The outer ring of the first stage angular bearing is fixed directly or indirectly, and is arranged in frictional contact with the angular bearing holding ring, and the driving force input shaft part and the first stage angular bearing are A bearing case containing the second-stage angular bearing;
In order to transmit the rotational driving force transmitted from the second-stage angular bearing to the cam barrel, it is coupled to a retainer that rotatably supports the ball of the second-stage angular bearing, and is on the rotation axis of the second-stage angular bearing. And a driving force output shaft fixed to be synchronously rotatable.
During the autofocus operation, the driving force transmitted from the driving source transmitted to the driving force input shaft is transmitted to the inner ring of the second-stage angular bearing, and at this time, the friction between the angular bearing holding ring and the bearing case The coupling state by the force is maintained, and the driving force output shaft portion rotates in synchronization with the inner ring of the second stage angular bearing to slide the lens holding frame to adjust the focus,
During the manual focus operation, the driving force transmitted by the photographer's operation is transmitted to the manual focus driving force input portion of the angular bearing retainer ring, and at this time, the angular force is transmitted by the driving force transmitted by the photographer's operation. The coupling state due to the frictional force between the bearing retainer ring and the bearing case is released, and the driving force output shaft portion rotates in synchronization with the outer ring of the second-stage angular bearing, so that the lens holding frame is slid to adjust the focus. The lens driving mechanism according to claim 1 to be performed.   The lens driving mechanism includes a structure in which the driving source is a DC motor, and the speed reduction mechanism fixes a worm gear to an output rotation shaft of the DC motor and meshes the worm gear with the worm wheel gear. Item 3. The lens driving mechanism according to Item 2. In the lens driving mechanism, the driving force input shaft portion is provided with a worm wheel gear that meshes with a worm gear fixed to the output rotation shaft of the DC motor at a predetermined position on the outer periphery thereof.
In the first-stage angular bearing, the outer ring on one end side is pressed toward the other end side by the elastic member, and the inner ring on the other end side is pressed toward the one end side so that the ball is clamped, and the driving force input shaft portion is held by the inner ring Support rotatably,
The second-stage angular bearing is configured such that an elastic member presses the outer ring on one end side toward the other end side and the inner ring on the other end side toward the one end side to pinch the ball, and the outer ring is against the bearing case. Frictionally coupled through the angular bearing retainer ring,
When the frictional coupling force between the angular bearing retainer ring and the bearing case is greater than the frictional coupling force set in the lens driving mechanism, the angular bearing retaining ring and the bearing case are maintained in a coupled state and autofocusing is performed. The operation was successful,
When the frictional coupling force between the angular bearing retainer ring and the bearing case is smaller than the frictional coupling force set in the lens driving mechanism, the outer ring of the second-stage angular bearing rotates and the manual focus operation is performed normally. The lens driving mechanism according to any one of claims 1 to 3. The speed reduction mechanism further includes an angular bearing pressing member that supports the first stage angular bearing,
The lens drive mechanism according to any one of claims 1 to 4, wherein the angular bearing pressing member is fixed to the bearing case so that the elastic force of the elastic member can be adjusted.   The lens driving mechanism according to claim 4, wherein the elastic member is a disc spring.   The lens drive mechanism according to any one of claims 1 to 6, wherein torque oil is applied to sliding surfaces of balls of the first-stage angular bearing and the second-stage angular bearing. The lens driving mechanism engages with a gear fixed to the driving force output shaft portion, and rotates around an optical axis.
An arm member having one end coupled to the focus gear ring and the other end coupled to a protrusion provided on the outer periphery of the cam barrel;
When the focus lens is slid in the optical axis direction, the driving force transmitted from the gear fixed to the driving force output shaft is rotated by the cam cylinder via the focus gear ring and the arm member to hold the lens. The lens drive mechanism according to claim 1, wherein the frame is slid. The lens driving mechanism includes a manual focus ring on the outer periphery of the lens barrel,
A manual focus ring gear in which one end side is fitted to the inner periphery of the manual focus ring, and the other end side is meshed with and coupled to a manual focus drive force input portion provided on the outer ring of the second stage angular bearing; With
9. The lens driving mechanism according to claim 1, wherein during manual focus operation by a photographer's operation, focus adjustment is performed by slidingly moving the lens holding frame by rotating the manual focus ring. .   A lens barrel using the lens driving mechanism according to claim 1.   An imaging apparatus using the lens barrel according to claim 10.

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