JP7294877B2 - LENS DRIVING DEVICE AND LENS UNIT AND CAMERA WITH THE SAME - Google Patents

Description

The present invention relates to a lens driving device, and more particularly to a lens driving device for linearly moving a lens, and a lens unit and a camera having the same.

Japanese Patent Laying-Open No. 9-107671 (Patent Document 1) describes a stepping motor. This stepping motor is built in a camera or the like and used to move a focusing lens, a zooming lens, or the like. The stepping motor is configured to rotate a rotating shaft, and a spiral groove is formed in the rotating shaft. By rotating the rotating shaft, the engaging member engaged with the groove is moved in the axial direction of the rotating shaft, thereby moving the lens.

A motor used to drive a focusing lens of a camera, such as the stepping motor described in Patent Document 1, requires a high-speed, High load and high precision rotation are required. In addition, it is also required to suppress noises such as clattering sounds that accompany the rotation of the rotary shaft. In the stepping motor disclosed in Patent Document 1, the tip of the rotating shaft is rotatably supported by a resin bearing, and the bearing is made of resin to reduce noise and vibration.

JP-A-9-107671

However, just by supporting one end of the rotating shaft with a simple sliding bearing as in the stepping motor described in Patent Document 1, it is not possible to sufficiently suppress radial deflection of the rotating shaft. , there is a problem of noise generation. That is, when one end of the rotating shaft is supported by a simple sliding bearing as in the stepping motor described in Japanese Patent Laid-Open No. 2002-200311, the following is required to allow for machining errors of each part, assembly errors, thermal expansion of the rotating shaft, etc. , it is necessary to provide a certain amount of clearance between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the sliding bearing.

Therefore, in the structure of the stepping motor described in Patent Document 1, it is difficult to sufficiently suppress radial deflection of the rotating shaft. In addition, if the clearance between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the sliding bearing is set small in this structure, the sliding resistance increases due to machining errors and assembly errors of each part, and the focusing lens etc. can be fed smoothly. becomes difficult. Such a problem of deflection of the rotating shaft becomes particularly conspicuous when a heavy lens or the like is moved by the lens driving device.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a lens driving device capable of moving a lens with high speed and high accuracy even when applied to a heavy lens, and a lens unit and a camera having the same. and

In order to solve the above-described problems, the present invention provides a lens driving device for linearly moving a lens, comprising a rotating shaft having a feed screw formed thereon and a radial sliding bearing that rotatably supports the rotating shaft. , a bearing support mechanism for supporting the radial sliding bearing, a driving motor for rotating the rotating shaft, and a carriage which is screwed to the feed screw and moves in the axial direction of the rotating shaft when the rotating shaft is driven to rotate. and, at least part of the outer peripheral surface of the radial sliding bearing is formed of a spherical surface centered on a predetermined center point, and the bearing support mechanism has a supporting surface that contacts the spherical surface of the radial sliding bearing. It is characterized in that it supports a radial sliding bearing so as to be rotatable about a central point.

According to the present invention configured as described above, the bearing support mechanism that supports the radial sliding bearing has a supporting surface that contacts the spherical surface, and supports the radial sliding bearing so as to be rotatable about the center point of the spherical surface. Inclination of the axis of rotation about the center point of the spherical surface is allowed. Therefore, even if the clearance between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the radial sliding bearing is set small, the rotational resistance of the rotating shaft does not increase greatly. As a result, it is possible to set a small clearance between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the radial plain bearing. becomes.

The present invention also provides a lens unit having a lens driving device, comprising a lens barrel, a lens arranged in the lens barrel, and a lens unit for moving the lens in the optical axis direction. and a lens driving device.

Furthermore, the present invention is a camera having a lens unit, and is characterized by having a camera body and the lens unit of the present invention attached to the camera body.

INDUSTRIAL APPLICABILITY According to the lens driving device of the present invention, and the lens unit and the camera having the same, even when applied to a heavy lens, the lens can be moved at high speed and with high accuracy.

1 is a schematic cross-sectional view of a camera according to an embodiment of the invention; FIG. 1 is a cross-sectional view of a lens driving device according to an embodiment of the present invention; FIG. FIG. 2 is an enlarged cross-sectional view showing a driving motor provided in the lens driving device according to the embodiment of the present invention; FIG. 4 is a cross-sectional view showing an enlarged bearing support mechanism provided in the lens driving device according to the embodiment of the present invention; It is a figure which expands and shows the edge part of the rotating shaft of the lens drive device by embodiment of this invention. It is a figure which expands and shows the end part of the rotating shaft by the modification of the lens drive device by embodiment of this invention. FIG. 5 is a diagram schematically showing a method of adjusting the mounting position of the bearing support mechanism in the lens driving device according to the embodiment of the present invention;

<Camera configuration>
BEST MODE FOR CARRYING OUT THE INVENTION Next, a lens driving device according to embodiments of the present invention, and a lens unit and a camera including the same will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a camera according to an embodiment of the invention. FIG. 2 is a cross-sectional view of a lens driving device according to an embodiment of the invention. FIG. 3 is a cross-sectional view showing an enlarged driving motor provided in the lens driving device according to the embodiment of the present invention. FIG. 4 is a cross-sectional view showing an enlarged bearing support mechanism provided in the lens driving device according to the embodiment of the present invention. FIG. 5 is an enlarged view of the end of the rotating shaft of the lens driving device according to the embodiment of the present invention.

As shown in FIG. 1, a camera 1 according to an embodiment of the invention has a lens unit 2 and a camera body 4 to which the lens unit 2 is attached. The lens unit 2 incorporates a lens barrel 6 , a plurality of lenses 8 arranged in the lens barrel 6 , and a lens driving device 10 . The lens driving device 10 is configured so that the carriage 12a can move in the direction of the optical axis A of the lens unit 2, thereby linearly moving the focusing lens 12 attached to the carriage 12a.

On the other hand, the camera body 4 incorporates an imaging element 14 . Light incident on the lens unit 2 is focused on the imaging element 14 by each lens 8 and the focusing lens 12 in the lens barrel 6 . When autofocus is set, the lens driving device 10 is operated based on a control signal sent from the camera body 4 to perform focus adjustment. During manual focus setting, the lens drive device 10 is operated based on the operation of the focus ring 6a provided on the lens unit 2, and focus adjustment is performed.

<Overall Configuration of Lens Driving Device>
Next, the configuration of the lens driving device 10 according to the embodiment of the present invention will be described with reference to FIGS. 2 to 5. FIG.
As shown in FIG. 2, the lens driving device 10 includes a rotating shaft 16, a driving motor 18 that drives the rotating shaft 16, a bearing portion 20 that rotatably supports the tip of the rotating shaft 16, and a driving motor. 18 and a frame member 22 connecting the bearing portion 20 . In this specification, the side of the lens driving device 10 on which the driving motor 18 is arranged (the right side in FIG. 2) is called the "motor side" or the "base end side", and the opposite side (the right side in FIG. 2). left side) is called the "tip side".

The rotating shaft 16 is a shaft that functions as a lead screw, and has a male thread formed on a part of its outer peripheral surface, which constitutes a feed screw 16a. A driving motor 18 is attached to one end of the rotating shaft 16 , and the driving motor 18 is configured to rotatably support the rotating shaft 16 and to rotationally drive the rotating shaft 16 . The other end of the rotating shaft 16 is rotatably supported by a bearing portion 20 . Therefore, the rotary shaft 16 is rotatably supported on both sides of the feed screw 16a. A female thread formed on the carriage 12a is screwed into the male screw thread of the feed screw 16a. is moved linearly to

The frame member 22 has a base plate 22a formed from an elongated thin plate, and a bearing support member 22b attached to the tip of the base plate 22a. The motor side of the base plate 22a is bent substantially at right angles, and the drive motor 18 is attached to this bent portion. A bearing support member 22b is attached to the end of the base plate 22a on the opposite side of the driving motor 18, and constitutes a part of the bearing portion 20. As shown in FIG.

<Structure of drive motor>
Next, the configuration of the driving motor 18 provided in the lens driving device 10 will be described with reference to FIG.
As shown in FIG. 3, the driving motor 18 includes a motor case 24, a stator core 26 attached to the motor case 24, a coil 28 attached to the stator core 26, and a magnet 30 attached to the rotating shaft 16. and have A motor-side radial sliding bearing 32 is provided at the tip end of the driving motor 18 to rotatably support the rotating shaft 16 .

The motor case 24 is a reinforced resin member formed to support the stator core 26 and the motor-side radial sliding bearing 32, and is fixed to the bent portion of the base plate 22a. The motor-side radial sliding bearing 32 extends through the bent portion of the base plate 22a and the motor case 24 to rotatably support the rotating shaft 16. As shown in FIG. In this embodiment, a sintered oil-impregnated bearing is used as the motor-side radial plain bearing 32 .

A thrust receiving recess 24a is formed at the end of the motor case 24 on the proximal side. A motor-side rubber damper 34, which is a first elastic member, and a motor-side thrust receiver 36, which is a sliding member, are held in the thrust receiving recess 24a.

The stator core 26 is a steel member having a disc portion 26a and six leg portions 26b (only two are shown in FIG. 3) extending from the periphery of the disc portion 26a. The disk portion 26a is a disk-shaped portion oriented in a direction orthogonal to the rotating shaft 16, and a motor-side radial sliding bearing 32 is attached so as to pass through the center of the disk portion 26a. The six leg portions 26b are elongate plate-like portions extending from the periphery of the disc portion 26a, and are provided at equal intervals around the disc portion 26a. Each leg portion 26b is bent substantially perpendicularly to the disk portion 26a and extends substantially parallel to the rotating shaft 16 toward the base end side so as to surround the end portion of the rotating shaft 16. As shown in FIG. In this embodiment, the stator core 26 is provided with six legs 26b, but the number of legs is not limited to this.

The coils 28 are formed by winding conductive wires around the base ends of the legs 26b of the stator core 26, respectively. By applying current to these coils 28 , each leg portion 26 b of the stator core 26 is magnetized and a driving force is generated between the magnets 30 .

The magnet 30 is a permanent magnet formed in a substantially cylindrical shape and is fixed to the end of the rotating shaft 16 , and the rotating shaft 16 extends through the inside of the magnet 30 . The magnet 30 has S poles and N poles alternately formed along its circumference. A rotational force is generated.

A thrust receiving recess 24a of the motor case 24 is provided so as to face the end face of the rotating shaft 16 extending through the magnet 30, and a rubber damper 34 and a thrust receiver 36 on the motor side are provided in the thrust receiving recess 24a. are placed. The rubber damper 34 is a block made of silicone rubber arranged in the thrust receiving recess 24a, and when it is elastically compressed, the elastic recovery force of the rubber damper 34 directs the rotating shaft 16 toward the distal end side in the first direction (see FIG. 3). leftward). The thrust receiver 36 is a circular thin plate made of PEEK resin arranged in the thrust receiving recess 24 a so as to cover the rubber damper 34 . Therefore, the thrust receiver 36 is pressed against the end surface of the rotating shaft 16 by the elastic recovery force of the rubber damper 34 , and the rubber damper 34 biases the end surface of the rotating shaft 16 in the thrust direction via the thrust receiver 36 .

As the rubber damper 34 on the motor side, an elastic member made of a resin material such as urethane rubber or nitrile rubber or a rubber material can be used in addition to silicone rubber. Further, as the thrust receiver 36 on the motor side, a polyslider or the like can be used in addition to the PEEK resin.

<Construction of the bearing>
Next, the configuration of the bearing portion 20 of the lens driving device 10 of this embodiment will be described with reference to FIG.
As shown in FIG. 4 , the bearing portion 20 is configured to rotatably support the tip of the rotating shaft 16 on the opposite side of the drive motor 18 . The bearing portion 20 is composed of a bearing support member 22b, a radial slide bearing 38 on the distal end side, and a bearing support mechanism 40 that supports the radial slide bearing 38. As shown in FIG.

The bearing support member 22b forms part of the frame member 22 and is fixed to the base plate 22a at the end opposite to the drive motor 18. As shown in FIG. The bearing support member 22b is a generally cylindrical member with a bearing support mechanism 40 received within its inner retaining inner wall surface 22c.

The radial slide bearing 38 is a slide bearing that rotatably supports the tip end of the rotating shaft 16 , and the tip of the rotating shaft 16 extends through the center of the radial slide bearing 38 . Further, the outer peripheral surface of the radial sliding bearing 38 is composed of a spherical surface 38a centered on a center point C (predetermined center point). A center point C of the spherical surface 38 a is located on the central axis of the rotating shaft 16 . In this embodiment, a sintered oil-impregnated bearing is used as the radial plain bearing 38, and the clearance between the outer peripheral surface of the rotating shaft 16 and the inner peripheral surface of the radial plain bearing 38 is about 5 μm to about 15 μm. It is preferable to set The same applies to the clearance between the motor-side radial sliding bearing 32 and the outer peripheral surface of the rotary shaft 16 described above.

The bearing support mechanism 40 includes a housing 42, a pair of bearing retainers 44 and 45 which are support members housed inside the housing 42, a wave washer 46 which is a plate spring for biasing the bearing retainers, and a second elastic member. It is composed of a rubber damper 48 on the tip end side, which is a member, and a thrust receiver 50, which is a sliding member.

The housing 42 is a cap-shaped member with a circular cross section, and accommodates each component of the bearing support mechanism 40 inside. The outer peripheral surface 42a of the housing 42 is received and fixed inside the holding inner wall surface 22c of the bearing support member 22b. The outer peripheral surface 42 a of the housing 42 forms the outer peripheral surface of the bearing support mechanism 40 , and the holding inner wall surface 22 c of the bearing support member 22 b forms the holding inner wall surface of the frame member 22 .

Further, a predetermined gap is provided between the outer peripheral surface 42a of the housing 42 and the holding inner wall surface 22c of the bearing support member 22b. As will be described later, this gap is filled with an adhesive 58 after performing a predetermined adjustment, and the bearing support mechanism 40 is fixed to the frame member 22 . That is, the outer peripheral surface 42a and the holding inner wall surface 22c are fixed apart from each other by a predetermined distance. The difference between the inner diameter of the holding inner wall surface 22c and the outer diameter of the outer peripheral surface 42a is preferably set to about 30 μm to about 200 μm, and is set to about 50 μm (micrometers) in this embodiment.

A stepped recess with a circular cross section is formed inside the housing 42. A rubber damper 48 and a thrust receiver 50 are arranged in a small-diameter recess 42b located on the far side, and a large-diameter recess located on the front side. Bearing retainers 44 and 45 are arranged at 42c.

The rubber damper 48 is a block made of silicone rubber, and when it is elastically compressed, the elastic recovery force of the rubber damper 48 directs the rotating shaft 16 toward the base end side in a second direction opposite to the first direction (FIG. 4). is biased to the right). The thrust receiver 50 is a circular thin plate made of PEEK resin arranged in the small-diameter concave portion 42 b of the housing 42 so as to cover the rubber damper 48 , and is arranged between the end face on the tip side of the rotating shaft 16 and the rubber damper 48 . there is Therefore, the thrust receiver 50 is pressed against the end face of the rotating shaft 16 by the elastic force of the rubber damper 48, and the rubber damper 48 urges the end face of the rotating shaft 16 via the thrust receiver 50 in the thrust direction.

As the rubber damper 48 on the tip side, an elastic member made of a resin material such as urethane rubber or nitrile rubber or a rubber material can be used in addition to silicone rubber. Further, as the thrust receiver 50 on the tip side, a polyslider or the like can be used in addition to the PEEK resin.

As described above, the proximal end surface of the rotating shaft 16 is urged toward the distal end by the rubber damper 34 and the thrust receiver 36 (FIG. 3), and the distal end surface of the rotating shaft 16 includes the rubber damper 48 and the thrust bearing. It is biased proximally by a receiver 50 (FIG. 4). Therefore, the rotating shaft 16 is supported without backlash in the thrust direction. In addition, since each end face of the rotating shaft 16 is urged through the thrust bearings 36 and 50 made of PEEK resin, the sliding resistance between the rotating shaft 16 and the respective thrust bearings is small, and the drive motor 18 It is possible to suppress the loss of torque that occurs.

Furthermore, as shown in FIG. 5, both end faces of the rotating shaft 16 (only one side is shown in FIG. 5) are spherical surfaces 16b, and the rotating shaft 16 is positioned near its central axis. , contact each thrust receiver with a very small contact area. As a result, the rotational resistance generated due to the contact between the rotating shaft 16 and the thrust receivers 36, 50 can be further reduced. Further, the radius of curvature of the spherical shape 16b is formed larger than the radius of the rotating shaft 16, but as a modification, the radius of curvature of the spherical shape can be formed smaller.

FIG. 6 is an enlarged view of the end of the rotating shaft according to the modification.
As shown in FIG. 6, the rotating shaft 116 according to the modification is formed such that the radius of curvature of the spherical shape 116b is substantially equal to the radius of the rotating shaft 116. As shown in FIG. As a result, the end surface of the rotating shaft 116 according to this modified example is substantially a hemispherical surface. The radius of curvature of the spherical shape at the end of the rotating shaft is appropriately determined based on the material of each thrust receiver, the magnitude of the biasing force of each rubber damper, the material of the rotating shaft, etc., so as to reduce rotational resistance and increase wear resistance. can be set.

Next, with reference to FIG. 4 again, the support structure of the radial sliding bearing 38 on the tip side will be described.
As shown in FIG. 4, the radial sliding bearing 38 is supported by being sandwiched between a pair of bearing retainers 44 and 45 in the large-diameter recess 42c of the housing 42. As shown in FIG.

The bearing retainers 44 and 45 are generally annular members, and are arranged on both sides of the radial sliding bearing 38 so as to sandwich the radial sliding bearing 38 . The outer diameters of these bearing retainers 44, 45 are substantially the same as the inner diameter of the large-diameter recess 42c of the housing 42, and the bearing retainers 44, 45 are received in the large-diameter recess 42c without backlash.

Further, as described above, the outer periphery of the radial slide bearing 38 is formed with the spherical surface 38a. On the other hand, the inner circumferences of the bearing retainers 44 and 45 are provided with support surfaces that come into contact with the spherical surface 38a, and support the radial sliding bearing 38 so as to be rotatable about the center point C of the spherical surface 38a. That is, the bearing retainers 44 and 45 are formed with supporting spherical surfaces 44a and 45a having shapes matching the spherical surface 38a, respectively, and the radial slide bearing 38 is sandwiched and supported from both sides by these supporting spherical surfaces 44a and 45a. be. As a result, the rotating shaft 16 supported by the radial sliding bearing 38 is allowed to tilt with the center point C as a fulcrum, and it is possible to absorb shape errors, assembly errors, etc. of the members constituting the lens driving device 10. can.

Further, a wave washer 46, which is a spherical biasing member, is arranged in a stepped portion between the large-diameter concave portion 42c and the small-diameter concave portion 42b of the housing 42. As shown in FIG. The wave washer 46 is formed by bending a doughnut-shaped thin metal plate into a wave shape. The wave washer 46 is configured such that when a compressive force is applied, the wave shape is elastically deformed and the thickness is reduced.

When assembling the bearing support mechanism 40, first, the rubber damper 48 and the thrust receiver 50 are arranged in the small-diameter concave portion 42b of the housing 42 in this order. Next, the wave washer 46, the bearing retainer 44, the radial sliding bearing 38, and the bearing retainer 45 are arranged in order from the inner side in the large-diameter concave portion 42c of the housing 42. As shown in FIG. In this state, the wave washer 46 is elastically deformed by pressing the bearing retainer 45 with a predetermined force so as to push it into the housing 42 . Further, in a state where the wave washer 46 is elastically deformed by a predetermined amount, an adhesive 52 is applied to the contact portion between the housing 42 and the bearing retainer 45 and hardened. In this embodiment, as the adhesive 52, an ultraviolet-curing/anaerobic-curing adhesive that cures when irradiated with ultraviolet rays or blocked from air is used. However, any adhesive that has the requisite adhesive strength can be used as adhesive 52 .

With the adhesive 52 cured, the bearing retainer 44 is urged toward the radial sliding bearing 38 by the elastic recovery force of the wave washer 46 . By this biasing force, the spherical support surface 44 a of the bearing retainer 44 and the spherical support surface 45 a of the bearing retainer 45 are pressed against the spherical surface 38 a of the radial sliding bearing 38 . That is, the spherical surface 38a of the radial sliding bearing 38 is sandwiched from both sides by the supporting spherical surfaces 44a and 45a, and the radial sliding bearing 38 is rotatably supported by the bearing retainers 44 and 45 without backlash.

<Method for adjusting the position of the bearing support mechanism>
Next, a method for adjusting the mounting position of the bearing support mechanism will be described with reference to FIG.
7A and 7B schematically show a method for adjusting the mounting position of the bearing support mechanism 40. FIG.

As described above, a predetermined gap is provided between the outer peripheral surface 42a of the housing 42 that constitutes the bearing support mechanism 40 and the holding inner wall surface 22c of the bearing support member 22b that constitutes the frame member 22 (Fig. 4). Therefore, when the housing 42 of the bearing support mechanism 40 is inserted into the holding inner wall surface 22c of the frame member 22, play exists between them. In adjusting the mounting position of the bearing support mechanism, as shown in FIG. 7, the lens driving device 10 assembled up to this state is vertically mounted on the adjustment table 54 with the driving motor 18 facing downward.

Next, the pressing rod 56 is pressed against the housing 42 of the bearing support mechanism 40 from above, and the housing 42 is pushed downward with a predetermined force. As a result, the rubber damper 34 (FIG. 3) accommodated in the thrust receiving recess 24a of the motor case 24 and the rubber damper 48 (FIG. 4) accommodated in the small diameter recess 42b of the housing 42 are elastically deformed by a predetermined amount. Accordingly, a predetermined biasing force is applied to the rotating shaft 16 from both ends in the thrust direction.

In this state, current is passed through the coil 28 of the driving motor 18 to rotate the rotating shaft 16 at a constant number of revolutions. Next, while the rotating shaft 16 is being rotated, the adjustment table 54 is horizontally moved by a very small distance, and the current flowing through the coil 28 of the driving motor 18 is measured. In addition to the direction indicated by the arrow in FIG. 7, the adjustment base 54 is also moved in the direction perpendicular to the plane of the drawing. As the adjustment table 54 moves in this manner, the housing 42 received in the bearing support member 22b is slightly moved within the holding inner wall surface 22c. Further, along with the movement of the adjustment table 54, the rotating shaft 16 supported by the radial slide bearing 38 is also slightly inclined with the center point C of the spherical surface 38a as a fulcrum.

In this manner, the current flowing through the coil 28 of the driving motor 18 is measured while the adjusting table 54 is moved two-dimensionally in the horizontal plane, and the adjusting table 54 is fixed at the position where the current is minimized. That is, when the housing 42 is positioned at an appropriate position within the holding inner wall surface 22c, the rotational resistance of the rotating shaft 16 is minimized, so that the current required to drive the drive motor 18 at a predetermined speed is low. be the minimum. With the parts of the lens driving device 10 positioned at the appropriate positions, the gap between the housing 42 and the holding inner wall surface 22c is filled with the adhesive 58 and hardened. In this embodiment, as the adhesive 58, an ultraviolet-curing/anaerobic-curing adhesive that cures when irradiated with ultraviolet light or blocked from air is used. However, as adhesive 58, any adhesive having the requisite adhesive strength can be used. This completes the position adjustment of the bearing support mechanism 40 and the attachment to the frame member 22 .

<Effect of the embodiment of the present invention>
According to the lens driving device 10 of the embodiment of the present invention, the bearing support mechanism 40 that supports the radial slide bearing 38 has a support surface that contacts the spherical surface 38a, and the radial slide bearing 38 is rotated around the center point C of the spherical surface 38a. Since it is rotatably supported, the inclination of the rotating shaft 16 with the center point C of the spherical surface 38a as a fulcrum is allowed (FIG. 4). Therefore, even when the clearance between the outer peripheral surface of the rotating shaft 16 and the inner peripheral surface of the radial sliding bearing 38 is set small, the rotational resistance of the rotating shaft 16 does not increase greatly. As a result, it is possible to set a small clearance between the outer peripheral surface of the rotating shaft 16 and the inner peripheral surface of the radial sliding bearing 38, suppress the vibration of the rotating shaft 16, and move the lens at high speed and with high accuracy. becomes possible.

Further, according to the lens driving device 10 of the present embodiment, the wave washer 46, which is a spherical biasing member, biases the bearing retainer 44, which is a supporting member, so that the supporting spherical surface 45a is pressed against the spherical surface 38a. The play between the spherical surface 38a of the sliding bearing 38 and the supporting spherical surfaces 44a, 45a of the bearing retainers 44, 45 can be substantially eliminated, and the vibration of the rotating shaft 16 can be further suppressed.

Furthermore, according to the lens driving device 10 of the present embodiment, the outer peripheral surface 42a of the bearing support mechanism 40 and the holding inner wall surface 22c of the frame member 22 are fixed with a predetermined distance therebetween. Movement in the radial direction of the rotating shaft 16 is allowed with respect to the frame member 22 . The relative movement between the bearing support mechanism 40 and the frame member 22 can absorb shape errors and assembly errors of each part, and it is possible to fix both in a state where the rotation resistance of the rotating shaft 16 is small. become. As a result, even when the clearance between the outer peripheral surface of the rotating shaft 16 and the inner peripheral surface of the radial sliding bearing 38 is set small, the rotational resistance of the rotating shaft 16 does not increase greatly, and the vibration of the rotating shaft 16 is suppressed. As a result, the focusing lens 12 can be moved at high speed and with high accuracy.

Further, according to the lens driving device 10 of the present embodiment, the adhesive 58 is filled between the outer peripheral surface 42a of the bearing support mechanism 40 and the holding inner wall surface 22c of the frame member 22 to fix the two. The bearing support mechanism 40 can be easily fixed to the frame member 22 in a state where the support mechanism 40 is adjusted to a position where the rotational resistance of the rotating shaft 16 is small.

Although preferred embodiments of the present invention have been described above, various modifications can be made to the above-described embodiments. In particular, in the above-described embodiments, the lens driving device was used to linearly move the focusing lens, but the lens driving device of this embodiment can be applied to move any lens other than the focusing lens. can. Also, in the above-described embodiments, the present invention is applied to a digital still camera having an image sensor, but the present invention can also be applied to video cameras and film cameras. In the above-described embodiment, both end surfaces of the rotating shaft are biased in the thrust direction. can.

Reference Signs List 1 camera 2 lens unit 4 camera body 6 lens barrel 6a focus ring 8 lens 10 lens driving device 12 focusing lens 12a carriage 14 image sensor 16 rotating shaft 16a feed screw 16b spherical shape 18 driving motor 20 bearing portion 22 frame member 22a base plate 22b Bearing support member 22c Holding inner wall surface 24 Motor case 24a Thrust receiving concave portion 26 Stator core 26a Disc portion 26b Leg portion 28 Coil 30 Magnet 32 Motor side radial slide bearing 34 Rubber damper (first elastic member)
36 thrust receiver (sliding member)
38 Radial sliding bearing 38a Spherical surface 40 Bearing support mechanism 42 Housing 42a Peripheral surface 42b Small diameter recess 42c Large diameter recess 44 Bearing retainer (support member)
44a support spherical surface 45 bearing retainer (support member)
45a support spherical surface (support surface)
46 wave washer (spherical biasing member)
48 rubber damper (second elastic member)
50 thrust receiver (sliding member)
52 Adhesive 54 Adjustment table 56 Push rod 58 Adhesive 116 Rotating shaft 116b Spherical shape

Claims (5)

A lens driving device for linearly moving a lens,
a rotating shaft on which a feed screw is formed;
a radial sliding bearing that rotatably supports the rotating shaft;
a bearing support mechanism for supporting the radial sliding bearing;
a driving motor that rotationally drives the rotating shaft;
a carriage that is screwed into the feed screw and moves in the axial direction of the rotary shaft when the rotary shaft is rotationally driven;
a frame member that holds the drive motor and the bearing support mechanism;
an elastic member that biases the end surface of the rotating shaft in the axial direction ;
The bearing support mechanism has a cap-shaped housing that receives the radial sliding bearing,
At least part of the outer peripheral surface of the radial sliding bearing is composed of a spherical surface centered on a predetermined center point,
The bearing support mechanism has a support surface that abuts on the spherical surface of the radial slide bearing, and supports the radial slide bearing so as to be rotatable about the center point ,
the housing having an outer peripheral surface, the outer peripheral surface being positioned around the radial plain bearing, the frame member having an inner retaining wall surface for receiving the outer peripheral surface of the housing to retain the housing;
A lens driving device , wherein the outer peripheral surface of the housing and the holding inner wall surface of the frame member are fixed with a predetermined distance therebetween . The bearing support mechanism includes two support members each provided with a support spherical surface as the support surface that sandwiches the spherical surface from both sides, and a spherical surface that biases the support member so that the support spherical surface is pressed against the spherical surface. 2. The lens driving device according to claim 1, further comprising: a force member. 2. The lens driving device according to claim 1 , wherein an adhesive is filled between the outer peripheral surface of said housing and the holding inner wall surface of said frame member, and said housing is fixed to said frame member. A lens unit comprising a lens driving device,
a lens barrel and
The lens arranged in this lens barrel,
a lens driving device according to any one of claims 1 to 3 for moving the lens in the optical axis direction;
A lens unit comprising: A camera comprising a lens unit,
camera body and
a lens unit according to claim 4 attached to the camera body;
A camera characterized by having:

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