JP2017040872A - Lens driving device, optical instrument, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress backlash of a rotational axis of a worm for driving a cam member, and to improve the accuracy of position detection of a lens.SOLUTION: In a lens driving device, a worm 61 and a gear 50 are engaged with each other so that a force toward a fixed direction is applied to the worm 61 as the worm 61 rotates. The worm 61 rotates to make a follower 36 come into contact with a wall surface part 43 and to make a bearing 64 come into contact with an end of the worm 61 or an end of a rotational axis of a motor 62 that faces the bearing 64, and thereby the motor 62 stops its rotation.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a lens driving device, an optical apparatus, and an electronic apparatus.

  As a lens driving device that moves a lens in the optical axis direction, a device that includes a driving gear (worm), a cam member that includes a gear meshing with the driving gear, and a follower provided on the outer periphery of the lens frame is known ( Patent Document 1).

  In the lens driving device, when the worm rotated by the motor rotates the cam member, the follower moves while contacting the cam portion that exerts the cam action of the cam member. When the follower moves in the optical axis direction of the lens by the cam action of the cam member, the lens also moves in the optical axis direction.

JP 2010-54892 A

  In a conventional lens driving device, an urging member such as a spring member that urges the rotating shaft in a certain direction is used in order to suppress rattling of the rotating shaft of the worm. However, depending on the relationship between the twist direction of the worm and the cam member driven by the worm, a force may be applied in a direction opposite to a certain direction for biasing the worm. In such a case, the spring member as the urging member contracts, and rattling occurs on the rotating shaft of the worm. If such a backlash of the rotating shaft occurs, the meshing between the gear rotating the cam member and the worm may be displaced, or the accuracy of the detecting means for detecting the position of the lens frame to which the follower is attached may be adversely affected. Inconvenience occurs. Further, due to this inconvenience, in an optical device such as a small camera equipped with a lens driving device, the focus range that can be adjusted by the user may be limited, or the focus accuracy of autofocus may be deteriorated.

  The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to suppress rattling of a rotating shaft of a worm that drives a cam member and to improve the accuracy of lens position detection.

In order to achieve the above object, a lens driving device according to the first aspect of the present invention provides:
A worm that rotates around a rotation axis by a motor;
A biasing member that biases the worm in a certain direction along the rotation axis;
A support member that is positioned in the fixed direction with respect to the worm and supports a rotating shaft of the worm;
A gear meshing with the worm;
A follower that protrudes from the outer periphery of the lens barrel that holds the lens inside;
A cam member that is coaxially fixed with the gear and guides the follower to move the lens tube in the optical axis direction of the lens;
A blocking portion formed on the cam member and blocking rotation of the cam member rotating in a first direction by contacting the follower;
With
The worm and the gear are meshed so that when the worm rotates in the second direction, a force in the fixed direction is applied to the worm,
When the worm rotates in the second direction, the follower comes into contact with the blocking portion, and the support member and the end of the worm or the end of the rotating shaft facing the support member abut against each other. Touch.

The blocking portion is a wall surface portion that rises in an axial direction of the cam member from an end portion on the opposite side to an end portion to which the gear of the cam member is fixed.
The cam member is formed by connecting one end portion at a low position of the wall surface portion and the other end portion at a high position, and is inclined so as to incline from the other end portion toward the one end portion around the axis of the cam member. An inclined surface portion having a surface;
The follower may be configured such that when the cam member rotates in the first direction, the cam member is guided by the inclined surface portion and abuts against the wall surface portion to prevent the cam member from rotating.

The inclined surface is formed so as to be inclined counterclockwise from the other end portion toward the one end portion when the shaft of the cam member is viewed from the follower.
The worm may be a worm having a drive gear twisted to the right when viewed from the follower.

The inclined surface is formed so as to be inclined from the other end portion toward the one end portion in a clockwise direction when the shaft of the cam member is viewed from the follower.
The worm may include a drive gear that is twisted to the left as viewed from the follower.

A detected piece protruding from the outer periphery of the lens tube;
A detection unit for detecting a position of the detected piece in the optical axis direction;
A control unit for controlling the drive amount of the motor based on the position of the detected piece detected by the detection unit in the optical axis direction;
May be further provided.

  In order to achieve the above object, an optical apparatus according to a second aspect of the present invention includes the lens driving device according to the first aspect.

  In order to achieve the above object, an electronic apparatus according to a third aspect of the present invention includes the lens driving device according to the first aspect.

  According to the present invention, it is possible to suppress rattling of the rotating shaft of the worm that drives the cam member and improve the accuracy of lens position detection. By enlarging the moving range of the lens, it is possible to widen the range in which the focus can be adjusted in the optical apparatus and electronic apparatus including the lens driving device of the present invention. Therefore, the user of the optical device or electronic device can easily perform the focus adjustment operation.

It is a figure which shows the principal part structure which expanded the whole structure and the principal part of the lens drive device which concerns on Embodiment 1 of this invention. 1 is an exploded perspective view of a lens driving device according to Embodiment 1. FIG. It is a perspective view of the state which removed the front cover of the lens drive device concerning Embodiment 1. FIG. 3 is a perspective view of a main part of the lens driving device according to Embodiment 1. FIG. FIG. 5A is a diagram illustrating the configuration of the worm, the spring, and the motor of the lens driving device according to the first embodiment, and FIG. 5B is the XX ′ line in FIG. It is typical sectional drawing in. FIG. 6A is a diagram illustrating the configuration of the worm, the spring, and the motor of the lens driving device according to the comparative example, and FIG. 6B is a diagram along the YY ′ line in FIG. It is typical sectional drawing. It is a perspective view of the state which removed the front cover of the lens drive device concerning Embodiment 2 of this invention. 6 is a perspective view of a main part of a lens driving device according to Embodiment 2. FIG. It is a perspective view of the state which removed the front cover of the lens drive device concerning a comparative example. FIG. 10 is a perspective view showing a state in which the rotating shaft of the worm protrudes downward in the lens driving device of FIG. 9. It is a figure which shows a response | compatibility with the cam diagram of this Embodiment 1, and the binary information detected by a position detection part. In this Embodiment 1, it is a figure which shows a response | compatibility with the binary diagram detected by the cam diagram and position detection part when the shift | offset | difference arises in the switching position of binary information. It is a figure which shows the correspondence of the deviation | shift amount of binary information, and the upper limit value and lower limit value of the motor corresponding to deviation | shift amount in this Embodiment 1. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all the drawings shown below, the same elements are denoted by the same reference numerals. Although the description will be made by using front and rear and left and right in the horizontal direction and up and down in the vertical direction, these directions are used for explanation and are not intended to limit the present invention.

(Embodiment 1)
As shown in FIGS. 1 to 3, the lens driving device 1 according to Embodiment 1 of the present invention includes a main body case 10, a front cover 20 that covers the front surface of the main body case 10, and a lens accommodated in the main body case 10. A cylinder 30, a cam member 40 that exerts a cam action to move the lens cylinder 30 in the optical axis direction, a gear 50 that is formed integrally with the cam member 40, and a drive device 60 that meshes with the gear 50 and drives the cam member 40. The position detector 70 for detecting the position of the lens tube 30 in the optical axis direction and a controller 80 are provided.

  As shown in FIG. 1 or 2, the main body case 10 includes a first opening 11 that opens in the optical axis direction L, a bottom portion 12, and a first guide that stands up from the bottom portion 12 in the optical axis direction L. A shaft 13, a second guide shaft 14, a third guide shaft 15, and a spring holding column 16 are also provided. In addition, four screw holes 17a, 17b, 17c, and 17d are formed around the body case 10 at intervals. The main body case 10 accommodates the lens barrel 30, the cam member 40, the gear 50, and the driving device 60 in the main body case 10 through the opening 11 of the main body case 10.

  As shown in FIG. 1 or FIG. 2, the front cover 20 includes a protrusion 21 that protrudes forward in the optical axis direction L, and the protrusion 21 has a second opening 22 that opens in the optical axis direction L. Is formed. Further, around the front cover 20, when the front cover 20 is attached to the main body case 10, the screw holes 24a, 24b, 24c and 24d are formed. The front cover 20 is attached to the main body case 10 by overlapping the corresponding screw holes of the main body case 10 and the front cover 20 and inserting the screws 25a, 25b, 25c, 25d into the respective screw holes and screwing them together. Fixed.

  As shown in FIG. 2 or 4, the lens barrel 30 includes a cylindrical portion 32 that holds the lens 31, a spring holding member 34 that is formed on the outer periphery of the cylindrical portion 32, and a guide member that is also formed on the outer periphery of the cylindrical portion 32. 35 and a follower 36 protruding from the guide member 35 in a direction perpendicular to the optical axis direction L. The lens tube 30 is provided with a through hole (not shown) that is slidably engaged with the third guide shaft 15.

  The spring holding member 34 has a spring insertion hole 34a penetrating in the optical axis direction L, and holds the spring member 33 slidably in the spring insertion hole 34a. The guide member 35 has a through hole 35a penetrating in the optical axis direction L, and engages with the first guide shaft 13 slidably in the through hole 35a.

  As shown in FIG. 1, the spring member 33 is a coil-shaped tension spring. One end of the spring member 33 is engaged with the bottom 12 of the main body case 10, and the outer periphery thereof is held in the spring insertion hole 34 a of the spring holding member 34. Thus, by attaching the front cover 20 to the first opening portion 11, the follower 36 provided in the lens tube 30 is caused to act so as to always contact the cam member 40.

  The lens barrel 30 receives the cam action of the cam member 40 and moves in the optical axis direction L of the lens 31, and the lens 31 moves back and forth in the optical axis direction L within the protruding portion 21 of the front cover 20.

  1-4, the cam member 40 is one of cylindrical solid cams, and the end surface of the cam member 40 has a surface (inclined surface 44) that is inclined with respect to a surface perpendicular to the optical axis direction L. However, since the inclined surface and the follower 36 are related, a cam action is exerted on the follower 36. Then, the follower 36 that has received the cam action moves along the optical axis direction L, thereby moving the lens barrel 30 in the optical axis direction.

  The cam member 40 includes a through-hole 41 that passes through the rotation axis 40 a that is arranged in parallel with the optical axis direction L, and an inclined surface portion 42 that is inclined with respect to a plane perpendicular to the optical axis direction L. The first guide shaft 13 is inserted into the through hole 41 to position the cam member 40 with respect to the optical axis direction L. In addition, the cam member 40 is rotated by the driving device 60 around a rotation shaft 40 a that is substantially the same axis as the first guide shaft 13 inserted into the through hole 41.

  A gear 50 formed coaxially with the rotation shaft 40a is provided on the outer periphery of one end of the cam member 40. The cam member 40 rotates around the rotation shaft 40a when the gear 50 is driven by the driving device 60. The follower 36 moves along the inclined surface portion 42 with the rotation of the cam member 40 and moves in the front-rear direction of the optical axis direction L. The detailed shape of the cam member 40 will be described later.

  As shown in FIGS. 1 to 5, the drive device 60 includes a worm 61 and a motor 62 that drives the worm 61. The motor 62 is disposed below the worm 61 and rotates around the rotation shaft 62 a to drive the worm 61. As the motor 62, for example, a stepping motor is applied. The motor 62 is not limited to a stepping motor, and a servo motor or other motors may be applied. The stepping motor applied in the first embodiment uses a two-phase excitation method, but is not limited thereto, and other excitation methods such as a one-phase excitation method may be applied.

  The worm 61 is integrally formed coaxially with the rotation shaft 62 a of the motor 62 and includes a rotation shaft 62 a that penetrates the worm 61. The worm 61 includes a right-handed worm in which the drive gear is twisted in the right direction and a left-handed worm in which the drive gear is twisted in the left direction when the optical axis direction L is viewed from the follower side. A left-handed worm in which the driving gear 61a is twisted to the left is used.

  A biasing member 63 is interposed between the lower end of the worm 61 and the upper end of the motor 62. The biasing member 63 applies a biasing force to the worm 61 in a fixed direction, in the first embodiment, upward. When the urging member 63 applies an urging force in the upward direction, rattling of the rotating shaft 62a is suppressed. For example, a conical coil spring is applied to the urging member 63. The biasing member 63 is not limited to a conical coil spring, and a leaf spring, other springs, or the like may be applied.

  The shaft end of the rotating shaft 62 a penetrating from the upper end of the worm 61 is supported by a bearing 64. The bearing 64 has a recessed portion 64a that opens downward, and receives the end of the rotating shaft 62a in the recessed portion 64a to support the rotating shaft 62a. As the bearing 64, various bearings such as a ball bearing and a rolling bearing can be applied as long as they can support the load applied to the shaft. Moreover, although the recessed part 64a of the bearing 64 in this Embodiment 1 is a shape provided with the bottom part 64b, it is not limited to such a shape. For example, the bottom 64b may not be provided, and the end of the rotating shaft 62a may have a shape that penetrates the bearing 64.

  As shown in FIGS. 2 and 4, the position detection unit 70 detects the detected piece 37 provided on the outer periphery of the cylindrical portion 32 and perpendicular to the optical axis direction L, and the position of the detected piece 37 in the optical axis direction L. Sensor 71 is provided. The sensor 71 causes a light emitting element (not shown) and a light receiving element (not shown) to face each other at a predetermined interval, irradiates detection light from the light emitting element to the light receiving element, and detects the position of the object therebetween. A transmissive photosensor. The sensor 71 outputs binary information depending on whether or not the detected piece 37 of the lens tube 30 blocks the detection light between the light emitting element and the light receiving element. That is, when the detection light is blocked, an L level signal is output, and when the detection light is not blocked, an H level signal is output.

  The controller 80 includes a processor, a memory, and the like, and stores a control program for the lens driving device 1 in a memory (not shown). The controller 80 controls the entire lens driving device 1 according to this control program.

  Based on the binary information output from the position detector 70, the controller 80 calculates the amount of deviation between the reference point that is the binary switching point and the original position that is the original switching point. And the drive amount of the drive device 60 is controlled according to the deviation | shift amount. Details of the control will be described later.

  Next, the shape of the cam member 40 will be described with reference to FIGS.

  As shown in FIGS. 3 and 4, the end of the cam member 40 on the follower 36 side, that is, the end opposite to the end on which the gear 50 is provided, extends from the end in the axial direction of the cam member 40. A wall surface portion 43 that stands up is formed. The wall surface portion 43 includes one end portion 43a of the standing portion and the other end portion 43b facing the one end portion. That is, in the optical axis direction L, the wall surface portion 43 includes a lower end portion 43a and a higher end portion 43b. An inclined surface portion 42 having an inclined surface 44 that is inclined about the rotation shaft 40a of the cam member 40 is formed by connecting the one end portion 43a and the other end portion 43b. That is, the spiral inclined surface portion 42 is formed from the other end portion 43b at the higher position toward the one end portion 43a at the lower position with the rotation shaft 40a as the center.

  The inclined surface portion 42 has an inclined surface 44 from the other end portion 43b at the high position toward the one end portion 43a at the lower position. The inclined surface 44 may be an inclined surface that goes around the periphery of the cam member 40 from the other end portion 43b at the high position toward the one end portion 43a at the lower position, or may be an inclined surface formed at a part of the periphery. Good.

  The shape of the cam member 40 can be generally expressed using a cam diagram. As a cam diagram of the cam member 40 according to the first embodiment, FIG. 11 shows a developed view around the rotation shaft 40a of the cam member 40. As shown in FIG.

  The following description will be made assuming that the lower end portion 43a of the inclined surface portion 42 is a cam bottom (CB) and the higher end portion 43b is a cam top (CT). The cam member 40 includes a flat portion (F1) having a predetermined length that continues from the cam bottom (CB), and an inclined portion (T, inclined surface 44) that rises from the end point of the flat portion (F1) toward the cam top (CT). ) And a flat portion (F2) having a predetermined length continuing from the end portion of the inclined portion (T).

  The follower 36 moves from the cam bottom (CB) of the cam member 40 to the cam top (CT) through the flat portion (F1), the inclined portion (T), and the flat portion (F2) by the rotation of the cam member 40. The lens barrel 30 moves forward in the optical axis direction L. Further, the follower 36 moves from the cam top (CT) of the cam member 40 to the cam bottom (CB) through the flat portion (F2), the inclined portion (T), and the flat portion (F1) by the rotation of the cam member 40. Thus, the lens barrel 30 moves rearward in the optical axis direction L.

  In addition, the shape of the cam member 40 shown by a cam diagram is not limited to the shape shown by FIG. The length of the flat part (F1), the length of the flat part (F2), and the inclination angle of the inclined part (T) in FIG. 11 depend on the size and performance of the optical apparatus to which the lens driving device 1 is applied. The design can be changed as appropriate.

  The inclined direction of the inclined surface 44 of the inclined surface portion 42 is, as shown in FIGS. 3 and 4, counterclockwise when viewed from the follower 36 in the optical axis direction L, and the other end portion 43 b that is the cam top, It inclines toward 43a.

  In the first embodiment, the worm 61 is a left-handed worm, and the cam member 40 rotates clockwise by rotating the worm 61 clockwise when the rotation shaft 62a of the motor 62 is viewed from below. When the follower 36 comes into contact with the wall surface portion 43 at the cam bottom, the cam member 40 is prevented from rotating.

  Further, the cam member 40 is rotated counterclockwise from the cam bottom to the cam top by rotating the worm 61 counterclockwise when the rotation shaft 62a of the motor 62 is viewed from below.

  Next, the relationship between the cam member 40, the binary information detected by the position detection unit 70, and the driving amount of the motor 62 will be described with reference to FIGS.

  The horizontal axis of the cam diagrams in FIGS. 11 and 12 indicates the drive amount (pulse) of the motor of the stepping motor. In the first embodiment, an L / H level signal switching point detected by the sensor 71 of the position detection unit 70 is used as a reference point to display a numerical value that increases or decreases. As shown by a signal line 110 in FIG. 11, the signal detected by the position detection unit 70 is switched between the L level and the H level based on the reference point P depending on whether or not the detection light is blocked by the follower 36. With this reference point P as a reference, the drive amount is displayed as an increasing value and a decreasing value. The vertical axis corresponds to the height of the cam, but in the first embodiment, the amount of movement of the lens barrel 30 moved in the optical axis direction L by the cam member 40 is shown. The movement amount of the lens barrel 30 is displayed as a numerical value that increases or decreases with the switching point of the L level and H level signals detected by the sensor 71 of the position detection unit 70 as a reference point. That is, the direction of moving forward in the optical axis direction L is a value that increases, and the direction of moving backward is a value that decreases.

  When the motor 62 rotates the cam member 40 via the worm 61 and moves the follower 36 in the optical axis direction L, if the cam member 40 rotates according to the drive amount of the motor 62, the lens barrel 30 is set. It can be moved in the optical axis direction L. However, if the cam member 40 cannot be rotated in accordance with the driving amount of the motor 62 due to rattling of the rotation shaft 62a of the motor 62, the reference point P for switching the L level and H level signals by the position detection unit 70 is A deviation occurs from the original reference point (origin position Q).

  In FIG. 12, a signal line 120 indicates a case where the L level and H level signals are switched at the original switching point (origin position Q), and the reference point at which the L level and H level signals are switched is shifted from the origin position. The case is indicated by signal line 121. In the signal line 121, the reference point P that is a switching point is located at a position shifted to the cam bottom side by −10 pulses as compared with the origin position Q. Therefore, it is necessary to correct the deviation.

  The controller 80 performs control so that the reference point P is corrected to the origin position Q by the shift amount α. By performing such control, the movement of the lens barrel 30 can be accurately controlled.

  When actually driving the lens driving device 1, it is necessary to control the driving amount of the motor 62 in consideration of such a shift amount α. That is, an upper limit value and a lower limit value are set for the drive amount of the motor 62, and the cam member 40 is controlled to rotate within a predetermined range. Such an upper limit value and a lower limit value are called so-called soft limits. Such a soft limit can eliminate the inconvenience such as the follower 36 falling off the cam member 40.

  Specifically, the controller 80 refers to the upper limit value and the lower limit value of the drive amount of the motor 62 with respect to the shift amount α, referring to the correspondence table of the shift amount α and the upper limit value / lower limit value of the drive amount stored in the memory. decide.

  FIG. 13 is a correspondence table between the deviation amount α and the upper limit value / lower limit value of the drive amount of the motor 62. The smaller the deviation amount α, the larger the upper limit value / lower limit value, and the larger the deviation amount, the smaller the upper limit value / lower limit value. The controller 80 calculates the shift amount α based on the position of the follower 36 in the optical axis direction detected by the position detection unit 70, and based on the calculated shift amount α, the shift amount α and the driving amount of the motor 62 are calculated. The upper limit value and the lower limit value of the drive amount of the motor 62 are determined with reference to the correspondence table between the upper limit value and the lower limit value. The drive amount of the motor 62 shown in FIG. 12 is determined with reference to the correspondence table, with the soft limit upper limit value of the motor 62 being +100 pulses and the soft limit lower limit value being −50 pulses. Further, the controller 80 refers to the determined upper limit value and lower limit value of the driving amount of the motor 62 and determines the upper limit value and the lower limit value of the movement of the lens barrel 30. The movement of the lens barrel 30 in the optical axis direction shown in FIG. 12 is set so that +0.6 mm is set as the soft limit upper limit value and −0.4 mm is set as the soft limit lower limit value corresponding to the soft limit of the motor 62.

  After the upper limit value and the lower limit value of the driving amount of the motor 62 are determined, the lens driving device 1 may be set manually by the manufacturer of the lens driving device 1 or automatically by the controller 80. It may be set.

  As a case where a large shift occurs between the switching reference point and the origin position, there is a lens driving device having the following configuration. Such a lens driving device will be described as a comparative example of the present invention with reference to FIGS.

  As shown in FIGS. 9 and 10, the cam member 400 in the comparative example is such that the inclination direction of the inclined surface 404 of the inclined surface portion 402 is the other end portion at a higher position in the clockwise direction when the optical axis direction L is viewed from the follower 36. It inclines toward the one end part 403a of the low position from 403b. That is, the inclination direction of the inclined surface 404 from the cam top to the cam bottom is opposite to that of the first embodiment. Further, the twist direction of the drive gear 61a of the worm 61 is a left-handed worm that is twisted to the left as in the first embodiment. Since the other configuration is the same as that of the first embodiment, the same reference numerals are given and description thereof is omitted.

  In the lens driving device 1 having such a configuration, as shown in FIG. 6, the worm 61 rotates counterclockwise when the rotation shaft 62 a of the motor 62 is viewed from below, and the gear 50 engaged with the worm 61 rotates. Then, the cam member 400 is rotated counterclockwise when the follower 36 is viewed from the optical axis direction L. Therefore, the follower 36 is guided from the cam top to the cam bottom along the inclined surface 404 and comes into contact with the wall surface portion 43. When the follower 36 comes into contact with the wall surface portion 43, the cam member 400 is prevented from rotating and stops rotating.

  When the motor 62 further rotates in this state, the left-handed twisted worm rotates counterclockwise, so that a downward force acts on the worm 61 as shown in FIG. Then, for example, the conical coil spring which is the urging member 63 contracts by receiving a force in the downward direction. Therefore, as the spring contracts, the rotation shaft 62a is lowered downward, and the shaft end of the rotation shaft 62a protrudes from the lower portion of the motor 62 as shown in FIGS. Therefore, rattling occurs on the rotating shaft 62a of the motor 62. And while the spring which is the urging member 63 contracts, idling occurs between the worm 61 which is a left-handed worm and the gear 50.

  In the lens driving device 1 of the comparative example having such a configuration, the rotational axis 62a of the motor 62 rotates while the spring contracts, so that the shift amount α between the switching reference point P and the origin position Q also increases. Therefore, the upper limit value and lower limit value of the motor drive amount determined by the controller 80 are also reduced. In such a cam member 400, the inclined surface 404 of the inclined surface portion 402 cannot be used effectively, and the moving range of the lens barrel 30 cannot be increased.

  Next, the operation of the lens driving device 1 according to the first embodiment will be described with reference to FIGS.

  When a switch (not shown) of the lens driving device 1 is turned on and the photographer operates to move the lens 31 forward in the optical axis direction L, the motor 62 causes the rotating shaft 62a of the motor 62 to move downward. When viewed, the worm 61 rotates clockwise, and the worm 61 formed coaxially with the rotating shaft 62a of the motor 62 also rotates. When the drive gear 61a of the worm 61, which is a left-handed worm, meshes with the gear 50, the cam member 40 is watched when the optical axis direction L is viewed from the follower 36 around the rotation axis 40a of the cam member 40. Rotate around. As the cam member 40 rotates, the follower 36 moves along the inclined surface portion 42 of the cam member 40 from the cam top that is the other end portion 43b of the wall surface portion 43 to the cam bottom that is the one end portion 43a. To do. The follower 36 moves to the front in the optical axis direction L by moving the inclined surface portion 42 of the cam member 40, and moves the lens barrel 30 to the front in the optical axis direction L.

  When the follower 36 comes into contact with the wall surface portion 43 at the cam bottom, the cam member 40 is prevented from rotating by the wall surface portion 43. When the rotation of the cam member 40 is prevented and the motor 62 further rotates, as shown in FIG. 5, the worm 61 of the left-handed worm rotates clockwise when the rotation shaft 62a of the motor 62 is viewed from below. Therefore, force is applied to the worm 61 in the direction toward the bearing 64, not in the direction in which the biasing member 63 is contracted. By such a force acting, the end of the rotating shaft 62a on the bearing 64 side and the bottom 64b of the recess 64a of the bearing 64 come into contact. Thus, the rotation of the motor 62 stops when the end of the rotating shaft 62a of the motor 62 and the bottom 64b of the bearing 64 come into contact with each other.

  The bearing 64 may be configured not to include the bottom portion 64b as described above, and the rotating shaft 62a to penetrate the bearing 64. Also in such a configuration, when the rotation shaft 62a further rotates after the rotation of the cam member 40 is blocked by the follower 36, the worm 61 faces the bearing 64, not the direction in which the urging member 63 contracts. Force is applied in the direction. Due to such a force acting, the end of the worm 61 facing the bearing 64 and the end of the bearing 64 facing the worm 61 come into contact with each other, and the rotation of the rotating shaft 62a is stopped.

  Further, in the bearing 64 having the bottom 64b, after the rotation of the cam member 40 is blocked by the follower 36, the contact between the end of the rotating shaft 62a on the bearing 64 side and the bottom 64b of the recess 64a of the bearing 64, and the worm The rotation of the rotary shaft 62a of the motor 62 is stopped by both or one of the contact between the end of the bearing 64 facing the bearing 64 and the end of the bearing 64 facing the worm 61. May be.

  On the other hand, when the photographer operates the lens 31 to move backward in the optical axis direction L, the motor 62 rotates counterclockwise when the rotation shaft 62a of the motor 62 is viewed from below, The worm 61 formed coaxially with the rotating shaft 62a also rotates. When the drive gear 61a of the worm 61, which is a left-handed worm, meshes with the gear 50, the cam member 40 is opposite to the rotation axis 40a of the cam member 40 when viewed in the optical axis direction L from the follower 36. Rotate clockwise. As the cam member 40 rotates, the follower 36 moves along the inclined surface portion 42 of the cam member 40 from the cam bottom, which is one end portion 43a of the wall surface portion 43, to the cam top, which is the other end portion 43b. To do. The follower 36 moves rearward in the optical axis direction L by moving the inclined surface portion 42 of the cam member 40, and moves the lens cylinder 30 rearward in the optical axis direction L.

  According to the first embodiment, after the follower 36 comes into contact with the wall surface portion 43 of the cam member 40, the worm 61 is applied with a force in the same direction as the direction in which the urging member 63 is urged. Since the gear 50 and the gear 50 are engaged with each other, backlash of the rotating shaft 62a of the motor 62 due to contraction of the biasing member 63 can be reduced. Further, the worm 61 does not idle.

  Further, according to the first embodiment, after the rotation of the cam member 40 is blocked by the follower 36, a force in the same direction as the force urged by the urging member 63 is applied to the worm 61. Contact between the end of the bearing 64 on the side of the bearing 64 and the bottom 64b of the recess 64a of the bearing 64, or contact between the end of the worm 61 facing the bearing 64 and the end of the bearing 64 facing the worm 61, The rotation of the motor 62 is reliably stopped. Accordingly, the contraction of the contraction of the urging member 63 does not occur, and the motor 62 does not idle.

  Furthermore, since the deviation of the contraction of the biasing member 63 does not occur, the degree of correction from the reference point to the origin position can be reduced. Accordingly, the range between the upper limit value and the lower limit value of the soft limit of the driving amount of the motor 62 determined by the controller 80 can be increased, so that the movement range of the lens during the autofocus operation can be increased.

(Embodiment 2)
The configuration of the lens driving device 1 according to Embodiment 2 will be described with reference to FIGS.

  As in the first embodiment, the lens driving device 1 includes a main body case 10, a front cover 20 that covers the front surface of the main body case 10, and a lens tube that is accommodated in the main body case 10, as shown in FIGS. 30, a cam member 40 that exerts a cam action for moving the lens barrel 30 in the optical axis direction of the lens, a gear 50 that is formed integrally with the cam member 40, and a drive device 60 that meshes with the gear 50 and drives the cam member. The position detector 70 for detecting the position of the lens tube 30 in the optical axis direction and a controller 80 are provided. The first embodiment and the second embodiment are different from each other in the configuration of the cam member 40 and the driving device 60, and the other configurations are the same. .

  As shown in FIGS. 7 and 8, a wall surface portion 43 is formed at the end portion of the cam member 40 on the follower 36 side so as to stand from the end portion in the axial direction of the cam member 40 as in the first embodiment. Has been. In the optical axis direction L, the wall surface portion 43 includes a lower end portion 43a and a higher end portion 43b. An inclined surface portion 42 having an inclined surface 44 that is inclined about the rotation shaft 40a of the cam member 40 is formed by connecting the one end portion 43a and the other end portion 43b.

  As shown in FIGS. 7 and 8, the direction of inclination of the inclined surface 44 of the inclined surface portion 42 is different from that of the first embodiment in the clockwise direction when viewed from the follower 36 in the optical axis direction L. It inclines toward the one end part 43a which is a cam bottom from the part 43b.

  As shown in FIGS. 1, 7, and 8, the drive device 60 includes a worm 61 and a motor 62 that drives the worm 61. Unlike the first embodiment, the worm 61 is a right-handed worm in which the drive gear 61a is twisted rightward when the optical axis direction L is viewed from the follower side.

  Next, the operation of the lens driving device 1 according to the second embodiment will be described with reference to FIGS.

  When a switch (not shown) of the lens driving device 1 is turned on and the photographer operates to move the lens 31 forward in the optical axis direction L, the motor 62 causes the rotating shaft 62a of the motor 62 to move downward. When viewed, the worm 61 rotates clockwise, and the worm 61 formed coaxially with the rotating shaft 62a of the motor 62 also rotates. When the drive gear 61a of the worm 61, which is a right-handed twisted worm, meshes with the gear 50, the cam member 40 is counteracted when the optical axis direction L is viewed from the follower 36 around the rotation axis 40a of the cam member 40. Rotate clockwise. As the cam member 40 rotates, the follower 36 moves along the inclined surface portion 42 of the cam member 40 from the cam top that is the other end portion 43b of the wall surface portion 43 to the cam bottom that is the one end portion 43a. To do. The follower 36 moves to the front in the optical axis direction L by moving the inclined surface portion 42 of the cam member 40, and moves the lens barrel 30 to the front in the optical axis direction L.

  When the follower 36 comes into contact with the wall surface portion 43 at the cam bottom, the cam member 40 is prevented from rotating by the wall surface portion 43. When the rotation of the cam member 40 is prevented and the motor 62 further rotates, the worm 61 is a right-handed worm and rotates clockwise when the rotation shaft 62a of the motor 62 is viewed from below. The force is applied in the direction toward the bearing 64, not in the direction in which the biasing member 63 is contracted. When such a force acts, the rotation of the motor 62 stops when the end of the rotating shaft 62a of the motor 62 and the bottom 64b of the bearing 64 come into contact with each other.

  The configuration of the bearing 64 may be a configuration in which the rotating shaft 62a penetrates the bearing 64 without including the bottom portion 64b, as in the first embodiment. In such a configuration, the end of the worm 61 that faces the bearing 64 and the end of the bearing 64 that faces the worm 61 come into contact with each other, and the rotation of the rotating shaft 62a stops.

  According to the second embodiment, after the cam member 40 is prevented from rotating by the follower 36, a force in the same direction as the force that the biasing member 63 biases is applied to the worm 61. The rotation of the motor 62 is reliably stopped by the contact between the end on the bearing 64 side and the bottom 64b of the recess 64a of the bearing 64. Therefore, there is no deviation of the contraction amount of the urging member 63, and rattling of the rotating shaft 62a of the motor 62 can be suppressed. Further, since the soft limit range of the driving amount of the motor 62 can be increased, the operating range of the lens barrel 30 can be set wide.

  Moreover, the effect of this invention can be easily show | played by using the right-handed twist worm which is an existing product.

  In the above embodiment, a transmissive photosensor is applied as the sensor 71. However, the present invention is not limited to this, and any sensor capable of detecting binary information may be used. A Hall element, a mechanical switch, or the like may be applied.

  In the above embodiment, a cylindrical solid cam is used as the cam member 40, but the present invention is not limited to this. Various cam members can be applied as long as the cam member has a shape in which a blocking portion for blocking the rotation of the cam member is provided on the end surface.

  The lens driving device 1 according to the first and second embodiments of the present invention is a unit that is mounted on an optical device, an electronic device, or the like, and is used to capture an image. Examples of optical equipment include consumer cameras such as digital cameras, in-vehicle cameras, surveillance cameras, medical cameras mounted on endoscopes, camcorders (movie cameras) for video recording, various inspection cameras, and robots There are cameras. Examples of electronic devices include mobile phones, smartphones, tablet terminals, and personal computers.

  The above-described embodiments are for explaining the present invention, and do not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications made within the scope of the claims and the meaning of the equivalent invention are considered as the scope of the present invention.

1 Lens drive device
DESCRIPTION OF SYMBOLS 10 Main body case 11 1st opening part 12 Bottom part 13 1st guide shaft 14 2nd guide shaft 15 3rd guide shaft 16 Spring holding pillar 17a-17d Screw hole 20 Front cover 21 Projection part 22 2nd opening part 23 Groove 24a-24d Screw hole 25a-25d Screw 30 Lens tube 31 Lens 32 Cylindrical portion 33 Spring member 34 Spring holding member 34a Spring insertion hole 35 Guide member 35a Through hole 36 Follower 37 Detected piece 40 Cam member 40a Rotating shaft 41 Through Hole 42 Inclined surface portion 43 Wall surface portion 43a One end portion 43b The other end portion 44 Inclined surface 50 Gear 60 Driving device 61 Worm 61a Driving gear 62 Motor 62a Rotating shaft 63 Energizing member 64 Bearing 64a Recessed portion 64b Bottom portion 70 Position detecting portion 71 Sensor 80 Controller 110, 120, 21 signal lines 400 cam member 402 inclined portion 403a end portion 403b second end portion 404 the inclined surface

Claims (7)

A worm that rotates around a rotation axis by a motor;
A biasing member that biases the worm in a certain direction along the rotation axis;
A support member that is positioned in the fixed direction with respect to the worm and supports a rotating shaft of the worm;
A gear meshing with the worm;
A follower that protrudes from the outer periphery of the lens barrel that holds the lens inside;
A cam member that is coaxially fixed with the gear and guides the follower to move the lens tube in the optical axis direction of the lens;
A blocking portion formed on the cam member and blocking rotation of the cam member rotating in a first direction by contacting the follower;
With
The worm and the gear are meshed so that when the worm rotates in the second direction, a force in the fixed direction is applied to the worm,
When the worm rotates in the second direction, the follower comes into contact with the blocking portion, and the support member and the end of the worm or the end of the rotating shaft facing the support member abut against each other. A lens driving device in contact. The blocking portion is a wall surface portion that rises in an axial direction of the cam member from an end portion on the opposite side to an end portion to which the gear of the cam member is fixed.
The cam member is formed by connecting one end portion at a low position of the wall surface portion and the other end portion at a high position, and is inclined so as to incline from the other end portion toward the one end portion around the axis of the cam member. An inclined surface portion having a surface;
The follower is guided by the inclined surface portion by the cam member rotating in the first direction and abuts against the wall surface portion to prevent the cam member from rotating.
The lens driving device according to claim 1. The inclined surface is formed so as to be inclined counterclockwise from the other end portion toward the one end portion when the shaft of the cam member is viewed from the follower.
The worm is a worm having a drive gear twisted to the right when viewed from the follower.
The lens driving device according to claim 2. The inclined surface is formed so as to be inclined from the other end portion toward the one end portion in a clockwise direction when the shaft of the cam member is viewed from the follower.
The worm is a worm having a drive gear twisted to the left as viewed from the follower.
The lens driving device according to claim 2. A detected piece protruding from the outer periphery of the lens tube;
A detection unit for detecting a position of the detected piece in the optical axis direction;
A control unit that controls the driving amount of the motor based on the position of the detected piece detected by the detection unit in the optical axis direction;
The lens driving device according to claim 1.   An optical apparatus including the lens driving device according to claim 1.   An electronic apparatus comprising the lens driving device according to claim 1.

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