JP7344672B2 - Lens drive device, lens unit equipped with the same, and camera - 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 camera equipped with the lens driving device.

JP-A-2014-195349 (Patent Document 1) describes a motor. This motor is built into a digital camera or the like and is used to move a lens or the like. The motor is configured to rotate a rotating shaft, and a spiral groove is formed in the rotating shaft. By rotating the rotating shaft, the movable part that engages with the spiral groove is moved in the axial direction of the rotating shaft, and the lens and the like are moved.

A motor mounted on a portable device, such as the motor described in Patent Document 1, is required to have high impact resistance in case of a fall or the like. Further, the motor described in Patent Document 1 includes a rotor having a rotating shaft, a cylindrical stator disposed around the rotor, and a bearing member rotatably supporting the rotating shaft on one side in the motor axis direction. It is equipped with Further, this motor includes a biasing member that is disposed on the opposite side of the rotating shaft with respect to the bearing member and includes a leaf spring portion that biases the rotating shaft toward the other side in the motor axis direction; An end is fixed to the stator on the opposite side of the rotating shaft to prevent the bearing member from coming off in the motor axis direction, and also covers the leaf spring part on one side to limit deformation of the leaf spring part in the motor axis direction. It is equipped with a board and. Therefore, the rotating shaft is elastically pressed against the bearing member by the plate spring portion, and wobbling in the axial direction of the rotating shaft is suppressed.

Japanese Patent Application Publication No. 2014-195349

However, in the motor described in Patent Document 1, the plate spring portion disposed at one end of the rotating shaft suppresses rattling in the axial direction of the rotating shaft, so it is difficult to obtain sufficient impact resistance. This problem becomes particularly noticeable when the weight of the movable part to be driven by the rotating shaft is large, as the impact force acting on the rotating shaft becomes large.
Therefore, the present invention provides a lens driving device that can obtain sufficient impact resistance against impact force applied by dropping or the like even when applied to a heavy lens, and a lens unit equipped with the same. The purpose is to provide cameras.

In order to solve the above-mentioned problems, the present invention provides a lens driving device for linearly moving a lens, which includes a rotating shaft on which a feed screw is formed, a drive motor that rotationally drives this rotating shaft, and a feed screw. a carriage that is screwed onto the screw and is moved in the axial direction of the rotary shaft when the rotary shaft is rotationally driven; and a first elastic member that biases the rotary shaft in the axial direction of the rotary shaft in a first direction. and a second elastic member that biases the rotating shaft in the axial direction of the rotating shaft in a second direction opposite to the first direction.

According to the present invention configured in this way, the first elastic member biases the rotating shaft in the first direction in the axial direction of the rotating shaft, and the first elastic member biases the rotating shaft in the axial direction of the rotating shaft in the opposite direction to the first direction. and a second elastic member that biases the rotating shaft in the second direction. Therefore, no matter in which direction the rotating shaft receives an impact load, one of the elastic members is compressed, so that the impact force can be absorbed and sufficient impact resistance can be obtained.

The present invention also provides a lens unit including a lens driving device, which includes a lens barrel, a lens disposed in the lens barrel, and a lens unit for moving the lens in the optical axis direction. It is characterized by having a lens driving device.

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

ADVANTAGE OF THE INVENTION According to the lens drive device of the present invention, and the lens unit and camera equipped with the same, even when applied to a heavy lens, it is possible to obtain sufficient impact resistance against impact force applied by dropping or the like. Can be done.

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. 2 is an enlarged cross-sectional view showing a drive motor included in a lens drive device according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view showing a bearing support mechanism provided in a lens driving device according to an embodiment of the present invention. FIG. 2 is an enlarged view showing an end portion of a rotation shaft of a lens driving device according to an embodiment of the present invention. FIG. 7 is an enlarged view showing an end portion of a rotating shaft according to a modification of the lens driving device according to the embodiment of the present invention. FIG. 3 is a diagram schematically showing a method for adjusting the mounting position of a bearing support mechanism in a lens driving device according to an embodiment of the present invention.

<Camera configuration>
Next, a lens driving device according to an embodiment of the present invention, a lens unit equipped with the same, and a camera 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 an enlarged cross-sectional view showing a drive motor included in a lens drive device according to an embodiment of the present invention. FIG. 4 is an enlarged sectional view showing a bearing support mechanism provided in a lens driving device according to an embodiment of the present invention. FIG. 5 is an enlarged view showing the end of the rotation 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 present invention includes a lens unit 2 and a camera body 4 to which the lens unit 2 is attached. The lens unit 2 includes a lens barrel 6, a plurality of lenses 8 disposed in the lens barrel 6, and a lens driving device 10. The lens driving device 10 is configured to be able to move a carriage 12a in the direction of the optical axis A of the lens unit 2, so that the focusing lens 12 attached to the carriage 12a is moved linearly.

On the other hand, the camera body 4 includes an image sensor 14 built therein. The light incident on the lens unit 2 is focused onto the image sensor 14 by each lens 8 in the lens barrel 6 and the focusing lens 12. When setting autofocus, the lens drive device 10 is operated based on a control signal sent from the camera body 4, and focus adjustment is performed. 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 drive 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.
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 section 20 that rotatably supports the tip of the rotating shaft 16, and a driving motor 18. 18 and a frame member 22 that connects the bearing part 20. Note that in this specification, the side of the lens drive device 10 where the drive motor 18 is arranged (the right side in FIG. 2) is referred to as the "motor side" or the "base end side", and the opposite side (the right side in FIG. The 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 20. Therefore, the rotating shaft 16 is rotatably supported on both sides of the feed screw 16a. Further, a female thread formed on the carriage 12a is screwed into the male thread of the feed screw 16a, and by rotating the rotating shaft 16, the carriage 12a is rotated parallel to the optical axis A in the axial direction of the rotating shaft 16. is moved in a straight line.

The frame member 22 includes 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 at a substantially right angle, and the drive motor 18 is attached to this bent portion. Further, a bearing support member 22b is attached to the end of the base plate 22a on the opposite side of the drive motor 18, and constitutes a part of the bearing section 20.

<Configuration of drive motor>
Next, with reference to FIG. 3, the configuration of the drive motor 18 provided in the lens drive device 10 will be described.
As shown in FIG. 3, the drive 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 has. Further, a motor-side radial sliding bearing 32 is provided at the end of the drive motor 18 on the front end side, and rotatably supports 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, and rotatably supports the rotating shaft 16. In this embodiment, a sintered oil-impregnated bearing is used as the motor-side radial sliding bearing 32.

Further, a thrust receiving recess 24a is formed at the proximal end of the motor case 24. 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 disk portion 26a and six leg portions 26b (only two legs are shown in FIG. 3) extending from the periphery of the disk portion 26a. The disk portion 26a is a disk-shaped portion oriented in a direction perpendicular to the rotating shaft 16, and a motor-side radial sliding bearing 32 is attached so as to pass through the center thereof. The six leg portions 26b are elongated plate-shaped portions extending from the periphery of the disk portion 26a, and are provided at equal intervals around the disk portion 26a. Further, each leg portion 26b is bent approximately at right angles to the disk portion 26a, and extends toward the base end substantially parallel to the rotation shaft 16 so as to surround the end portion of the rotation shaft 16. In addition, in this embodiment, although the stator core 26 is provided with six leg parts 26b, the number of leg parts is not limited to this.

The coil 28 is formed by winding a conductive wire around the base end of each leg 26b of the stator core 26. By passing current through these coils 28, each leg 26b of the stator core 26 is magnetized, and a driving force is generated between it and the magnet 30.

The magnet 30 is a permanent magnet formed into 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, and each leg 26b of the stator core 26 arranged around the magnet 30 is sequentially magnetized, so that the magnet 30 Rotational force is generated.

The thrust receiving recess 24a of the motor case 24 is provided so as to face the end face of the rotating shaft 16 that extends through the magnet 30, and the motor-side rubber damper 34 and the thrust receiver 36 are installed in the thrust receiving recess 24a. It is located. The rubber damper 34 is a block made of silicone rubber placed in the thrust receiving recess 24a, and when it is elastically compressed, its elastic recovery force directs the rotating shaft 16 toward the distal end in the first direction (in FIG. 3). is biased toward the left). The thrust receiver 36 is a circular thin plate made of PEEK resin placed in the thrust receiver recess 24 a so as to cover the rubber damper 34 , and is arranged between the end surface of the rotating shaft 16 and 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 urges the end surface of the rotating shaft 16 in the thrust direction via the thrust receiver 36.

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

<Structure of bearing part>
Next, with reference to FIG. 4, the configuration of the bearing section 20 of the lens driving device 10 of this embodiment will be described.
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 section 20 includes a bearing support member 22b, a radial sliding bearing 38 on the tip side, and a bearing support mechanism 40 that supports the radial sliding bearing 38.

The bearing support member 22b constitutes a part of the frame member 22, and is fixed to the base plate 22a at the end opposite to the drive motor 18. The bearing support member 22b is a generally cylindrical member, and the bearing support mechanism 40 is received within the holding inner wall surface 22c inside the bearing support member 22b.

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

The bearing support mechanism 40 includes a housing 42, a pair of bearing retainers 44 and 45 that are supporting members housed inside the housing 42, a wave washer 46 that is a leaf spring that biases the bearing retainers, and a second elastic member. It is composed of a rubber damper 48 on the tip 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 therein. 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 circumferential surface 42a of the housing 42 constitutes the outer circumferential surface of the bearing support mechanism 40, and the holding inner wall surface 22c of the bearing support member 22b constitutes 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 adhesive 58 after 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. Note that the difference between the inner diameter of the holding inner wall surface 22c and the outer diameter of the outer circumferential surface 42a is preferably set to about 30 μm to about 200 μm, and in this embodiment, it is set to about 50 μm (micrometers).

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 the small diameter recess 42b located on the back side, and the 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, its elastic recovery force directs the rotating shaft 16 toward the proximal end in a second direction opposite to the first direction (FIG. 4). (in the right direction). The thrust receiver 50 is a circular thin plate made of PEEK resin that is placed in the small diameter recess 42 b of the housing 42 so as to cover the rubber damper 48 , and is placed between the end surface 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 surface of the rotating shaft 16 by the elastic force of the rubber damper 48, and the rubber damper 48 urges the end surface of the rotating shaft 16 in the thrust direction via the thrust receiver 50.

Note that as the rubber damper 48 on the tip side, in addition to silicone rubber, 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 PEEK resin, polyslider or the like can be used as the thrust receiver 50 on the tip side.

As described above, the proximal end surface of the rotating shaft 16 is biased 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 is biased toward the distal end by the rubber damper 48 and the thrust receiver 36 (FIG. 3). It is urged toward the proximal end by the receiver 50 (FIG. 4). Therefore, the rotating shaft 16 is supported without play in the thrust direction. In addition, since each end face of the rotating shaft 16 is biased via the thrust receivers 36 and 50 made of PEEK resin, the sliding resistance between the rotating shaft 16 and each thrust receiver is small, and the drive motor 18 The torque loss that occurs can be suppressed.

Furthermore, as shown in FIG. 5, the end surfaces on both sides of the rotating shaft 16 (only one side is shown in FIG. 5) have a spherical shape 16b, and the rotating shaft 16 has a spherical shape 16b near its central axis. , in contact with each thrust receiver with a very small contact area. Thereby, the rotational resistance generated based on the contact between the rotating shaft 16 and each thrust receiver 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 also be formed smaller.

FIG. 6 is an enlarged view showing an end portion of a rotating shaft according to a modified example.
As shown in FIG. 6, the rotating shaft 116 according to the modified example is formed so that the radius of curvature of the spherical shape 116b is approximately 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 modification is generally formed of a hemispherical surface. The radius of curvature of the spherical shape at the end of the rotating shaft is determined appropriately based on the material of each thrust receiver, the magnitude of the urging force by each rubber damper, the material of the rotating shaft, etc., so that rotational resistance is small and wear resistance is high. Can be set.

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

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 therebetween. The outer diameter of these bearing retainers 44, 45 is approximately 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 play.

Moreover, as mentioned above, the spherical surface 38a is formed on the outer periphery of the radial sliding bearing 38. On the other hand, a support surface that comes into contact with the spherical surface 38a is provided on the inner periphery of each bearing retainer 44, 45, and supports 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 respectively formed with supporting spherical surfaces 44a and 45a having shapes that match the spherical surface 38a, and the radial sliding bearing 38 is supported by being sandwiched from both sides by these supporting spherical surfaces 44a and 45a. Ru. 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 each member constituting the lens driving device 10. can.

Furthermore, a wave washer 46, which is a spherical biasing member, is arranged at a step between the large diameter recess 42c and the small diameter recess 42b of the housing 42. The wave washer 46 is formed by curving a donut-shaped thin metal plate into a wave shape. This wave washer 46 is configured such that when compressive force is applied, the waveform 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 placed in the small diameter recess 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 the large diameter recess 42c of the housing 42 in this order from the back side. In this state, when the bearing retainer 45 is pressed with a predetermined force so as to be pushed into the housing 42, the wave washer 46 is elastically deformed. Further, while 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, the adhesive 52 is an ultraviolet curing/anaerobic curing adhesive that is cured by ultraviolet irradiation or by blocking air. However, any adhesive having the necessary adhesive strength can be used as the adhesive 52.

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

<How to adjust 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.
FIG. 7 is a diagram schematically showing a method for adjusting the mounting position of the bearing support mechanism 40.

As described above, a predetermined gap is provided between the outer circumferential surface 42a of the housing 42 constituting the bearing support mechanism 40 and the holding inner wall surface 22c of the bearing support member 22b constituting the frame member 22 (see 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, there is play between them. To adjust the mounting position of the bearing support mechanism, as shown in FIG. 7, the lens drive device 10 assembled to this state is mounted vertically on the adjustment table 54 with the drive 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 pressed down 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 applied to the coil 28 of the drive motor 18 to rotate the rotating shaft 16 at a constant rotation speed. Next, while rotating the rotating shaft 16, the adjustment table 54 is moved a small distance in the horizontal direction, and the current flowing through the coil 28 of the drive motor 18 is measured. Note that the adjustment table 54 is moved not only in the direction indicated by the arrow in FIG. 7 but also in a direction perpendicular to the plane of the drawing. With such movement of the adjustment table 54, the housing 42 received by the bearing support member 22b is slightly moved within the holding inner wall surface 22c. Further, as the adjustment table 54 moves, the rotating shaft 16 supported by the radial sliding bearing 38 is also slightly tilted about the center point C of the spherical surface 38a.

In this way, the current flowing through the coil 28 of the drive motor 18 is measured while moving the adjustment table 54 two-dimensionally within the horizontal plane, and the adjustment table 54 is fixed at the position where the current is the minimum. That is, when the housing 42 is properly positioned 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 reduced. The minimum. In this manner, with each component of the lens driving device 10 properly positioned, the adhesive 58 is filled into the gap between the housing 42 and the holding inner wall surface 22c, and is allowed to harden. In this embodiment, the adhesive 58 is an ultraviolet curing/anaerobic curing adhesive that is cured by ultraviolet irradiation or by blocking air. However, any adhesive having the necessary adhesive strength can be used as adhesive 58. This completes the position adjustment of the bearing support mechanism 40 and the attachment to the frame member 22.

<Effects of the embodiments of the present invention>
According to the lens driving device 10 of the embodiment of the present invention, the rubber damper 34, which is the first elastic member that biases the rotating shaft 16 in the first direction, A rubber damper 48, which is a second elastic member, biases the rotating shaft 16 in a second direction opposite to the first direction. Therefore, no matter in which direction the rotating shaft 16 receives an impact load, one of the rubber dampers is compressed, so that the impact force can be absorbed and sufficient impact resistance can be obtained.

Further, according to the lens driving device 10 of the present embodiment, the rubber damper 34 biases one end surface of the rotating shaft 16 toward the bearing portion 20, and the rubber damper 48 biases the other end surface of the rotating shaft 16 for driving purposes. Since it is configured to bias toward the motor 18, the contact area between each thrust receiver 36, 50, which is a sliding member, and the rotating shaft 16 can be reduced, and the rotational resistance of the rotating shaft 16 is reduced. be able to.

Furthermore, according to the lens driving device 10 of this embodiment, both end surfaces of the rotating shaft 16 are each formed into a spherical shape 16b, so that the contact area between each thrust receiver 36, 50 and the rotating shaft 16 is further reduced. Therefore, the rotational resistance of the rotating shaft 16 can be minimized.

Further, according to the lens driving device 10 of the present embodiment, the rubber damper 34 and the rubber damper 48 bias the rotating shaft 16 via the thrust receivers 36 and 50, which are sliding members, respectively, so that the rotating shaft 16 and each thrust The frictional force acting between the receivers 36 and 50 can be reduced, and the rotational resistance of the rotating shaft 16 can be minimized.

Further, according to the lens driving device 10 of this embodiment, the rubber dampers 34 and 48, which are the first and second elastic members, are made of a rubber material and generate a biasing force by being elastically compressed. A large amount of deformation can be secured, and a large amount of impact energy can be absorbed without being damaged. Thereby, impact resistance can be improved.

Although preferred embodiments of the present invention have been described above, various changes can be made to the embodiments described above. In particular, in the embodiments described above, the lens driving device was used to move the focusing lens in a straight line, but the lens driving device of this embodiment can be applied to moving any lens other than the focusing lens. can. Further, in the embodiments described above, the present invention is applied to a digital still camera equipped with an image sensor, but the present invention can also be applied to a video camera or a film camera. Furthermore, in the embodiment described above, the end faces on both sides of the rotating shaft are biased in the thrust direction, but it is also possible to provide a stepped portion in the middle of the rotating shaft and apply a biasing force in the thrust direction to this stepped portion. can.

1 Camera 2 Lens unit 4 Camera body 6 Lens barrel 6a Focus ring 8 Lens 10 Lens drive device 12 Focusing lens 12a Carriage 14 Image sensor 16 Rotation shaft 16a Feed screw 16b Spherical shape 18 Drive 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 recess 26 Stator core 26a Disk portion 26b Leg portion 28 Coil 30 Magnet 32 Motor side radial sliding 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 Outer 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 stand 56 Pressing rod 58 Adhesive 116 Rotating shaft 116b Spherical shape

Claims (5)

A lens driving device for linearly moving a lens,
A rotating shaft with a feed screw formed thereon;
A drive motor that rotationally drives this rotating shaft,
a carriage that is screwed onto the feed screw and is moved in the axial direction of the rotary shaft when the rotary shaft is rotationally driven;
a first elastic member that biases the rotating shaft in a first direction in the axial direction of the rotating shaft;
a second elastic member that biases the rotating shaft in the axial direction of the rotating shaft in a second direction opposite to the first direction;
The first elastic member and the second elastic member are respectively disposed between the first elastic member and one end surface of the rotating shaft and between the second elastic member and the other end surface of the rotating shaft. a sliding member with an outer diameter larger than that of the
a first recess provided on one side of the rotating shaft to accommodate the first elastic member and the sliding member;
a second recess provided on the other side of the rotating shaft to accommodate the second elastic member and the sliding member;
The first elastic member and the second elastic member are blocks made of a resin material or a rubber material, and generate a biasing force by being elastically compressed;
A space between the first elastic member and the inner circumferential wall surface of the first recess, and between the second elastic member and the inner circumferential wall surface of the second recess are formed in a direction perpendicular to the axis of the rotating shaft. A lens driving device characterized in that a gap is formed. The first elastic member biases one end surface of the rotating shaft in the first direction, and the second elastic member biases the other end surface of the rotating shaft in the second direction. The lens driving device according to claim 1, wherein the lens driving device is configured as follows. 3. The lens driving device according to claim 2, wherein both end surfaces of the rotating shaft are each formed into a spherical shape. A lens unit including a lens drive device,
lens barrel and
The lens placed inside this lens barrel,
A lens driving device according to any one of claims 1 to 3 for moving this lens in the optical axis direction;
A lens unit characterized by having. A camera equipped with a lens unit,
camera body and
The lens unit according to claim 4, which is attached to the camera body;
A camera characterized by having:

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