JP5631673B2 - Light intensity adjustment device - Google Patents

Description

  The present invention relates to a light amount adjusting device provided in, for example, a digital camera, and more particularly to a light amount adjusting device including a motor mechanism.

  For example, a stepping motor shown in FIGS. 9 and 10 is known as a conventional drive source of the light amount adjusting device (Patent Document 1). FIG. 9 is a longitudinal sectional view schematically showing an example of a conventional stepping motor, and FIG. 10 is a partial sectional view schematically showing a state of magnetic flux flowing from the stator of the stepping motor shown in FIG.

  In the stepping motor shown in FIG. 9, two bobbins 101 around which a stator coil 105 is wound concentrically are arranged side by side in the axial direction, and these two bobbins 101 are clamped and fixed to different stator yokes 106, respectively. Has been. On the inner diameter surface of the stator yoke 106, stator teeth 106a and 106b that are alternately arranged along the circumferential direction are formed. A stator yoke 106 integral with the stator teeth 106a or 106b is fixed to each of the two cases 103. Thus, two stators 102 corresponding to the two stator coils 105 for excitation are formed.

  The flange 115 and the bearing 108 are fixed to one case of the two cases 103, and the bearing 108 is fixed to the other case 103. In the rotor 109, a rotor magnet 111 is fixed to a rotor shaft 110, and the rotor magnet 111 forms a radial gap with the stator yoke 106 of the two stators 102.

  The rotor shaft 110 is rotatably supported by two bearings 108. As shown in FIG. 10, the magnetic flux generated by energizing the stator coil 105 mainly passes through the end face 106a1 of the stator tooth 106a and the end face 106b1 of the stator tooth 106b.

  Further, as a conventional drive source of the light amount adjusting device, for example, a stepping motor shown in FIGS. 11 and 12 is known (Patent Document 2). 11 is an exploded perspective view of a conventional stepping motor, and FIG. 12 is a cross-sectional view along the axial direction of the stepping motor shown in FIG. 11 in an assembled state.

  11 and 12, the rotor 21 includes a cylindrical magnet portion made of a permanent magnet, and shaft portions 21t and 21s provided at both ends of the magnet portion. The magnet portion is alternately magnetized with S and N poles in the circumferential direction, and the shaft portions 21t and 21s and the magnet portion are integrally formed by molding or bonding to shorten the radial dimension. Yes.

  The shaft portions 21t and 21s of the rotor 21 are rotatably fitted in the fitting holes 22h of the stator 22 and the fitting holes 25a of the cover 25, respectively. The stator 22 is made of a soft magnetic material, has a cylindrical portion 22g that forms an internal magnetic pole portion, and has a comb-shaped first outer magnetic pole portion that extends parallel to the axis of the inner cylindrical portion 22g on the outer peripheral side of the inner cylindrical portion 22g. 22a, 22b, 22c and second outer magnetic pole portions 22d, 22e, 22f.

  The first and second outer magnetic pole portions 22a to 22c and 22d to 22f are wound with the first and second coils 23 and 24, respectively, and are excited and energized by energizing the coils 23 and 24. The acting magnetic flux acts on the magnet portion of the rotor 21.

  Furthermore, for example, a stepping motor shown in FIG. 13 is known as a conventional drive source of the light amount adjusting device (Patent Document 3). FIG. 13 is a cross-sectional view along the axial direction of a conventional stepping motor.

  Also in the stepping motor shown in FIG. 13, the coil 38 is vertically placed in parallel with the rotation shaft 36 of the rotor 37 and the nonmagnetic member 30 is interposed, as in the above-mentioned Patent Document 2.

  Furthermore, for example, a stepping motor shown in FIG. 14 is known as a conventional drive source of the light amount adjusting device (Patent Document 4). FIG. 14 is a perspective view showing a main part of a conventional stepping motor.

  In FIG. 14, the rotor 47 is attached to the lens barrel base plate 41 so as to be rotatable about a rotation shaft 47e, and is divided and magnetized into two portions 47a and 47b in the radial direction. The rotor 47 is provided with a magnetized layer divided into two layers in the axial direction.

  The first stator 48 has magnetic pole portions 48 a and 48 b, and these magnetic pole portions 48 a and 48 b are fixed to the barrel base plate 41 so as to be adjacent to the rotor 47. The second stator 49 is also fixed to the barrel base plate 41 so that the magnetic pole portions 49 a and 49 b are adjacent to the rotor 47 and at a position opposite to the first stator 48. In addition, coils 45 and 46 for exciting the respective magnetic pole portions are wound around the stators 48 and 49.

  FIG. 15 is an exploded perspective view of a conventional light amount adjusting device using the stepping motors of Patent Documents 1 to 4 as a drive source (Patent Document 5).

  In FIG. 15, the diaphragm blades 51 to 57 are made of synthetic resin or the like, and have thin plate-like first base portions 51 a to 57 a and second base portions 51 b to 57 b that have a light shielding property and adjust the opening amount. First shaft portions 51c to 57c are integrally formed on one surface of the first base portions 51a to 57a, and second shaft portions 51d to 57d (partially not shown) are integrally formed on the other surface. ing.

  The rotating member 58 is a member that drives the diaphragm blades 51 to 57, and is formed in a ring shape having an opening 58a at the center. The rotation member 58 is provided with holes 58b to 58h, a rotation fitting projection 58i, a gear 58j, and a light shielding portion 58k.

  The cam member 59 is a ring-shaped member having an opening 59a at the center, and the opening 9a defines the maximum opening amount that is adjusted by the diaphragm blades 51 to 57. The cam member 59 is provided with cam groove portions 59b to 59h.

  The pressing member 60 is a ring-shaped pressing member having an opening 60a in the center, and the pressing member 60 is provided with a hole 60b and a motor mounting portion 60c.

  The stepping motor 61 is for driving the rotating member 58 and is attached to the motor attachment portion 60 c of the pressing member 60. At that time, the pinion 62 fixed to the motor shaft of the stepping motor 61 passes through the hole 60b of the pressing member 60 and meshes with the gear portion 58j of the rotating member 58. The stepping motor 61 is a two-phase PM type stepping motor having two general coils.

  That is, the pinion 62 fixed to the motor shaft of the stepping motor 61 and the gear portion 58j of the rotating member 58 are engaged with each other so that the rotating member 58 and the stepping motor 61 are gear-connected.

  The initial position sensor 63 detects whether or not the rotating member 58 is in the initial position state by detecting whether the light shielding portion 58k of the rotating member 58 is inserted into or retracted from the initial position sensor 63.

  The pressing member 60 is fixed to the cam member 59 with the rotation member 58 and the diaphragm blades 51 to 57 interposed therebetween, and plays a role of preventing the rotation member 58 and the diaphragm blades 51 to 57 from coming off in the optical axis direction. At that time, the rotation fitting protrusion 58 i of the rotating member 58 is fitted to the opening 60 a of the pressing member 60 and is rotatably supported. The first shaft portions 51c to 57c of the diaphragm blades 51 to 57 are rotatably fitted in the holes 58b to 58h of the rotating member 58, respectively, and the second shaft portions 51d to 57d are cam members 59, respectively. Are slidably fitted to the cam groove portions 59b to 59h.

  The diaphragm blades 51 to 57 are evenly arranged in the circumferential direction around the optical axis, and the aperture openings can be controlled by overlapping the first base parts 51a to 57a and the second base parts 51b to 57b having light shielding properties. The larger the overlap area, the smaller the aperture opening amount.

JP 2005-143207 A JP 2004-064876 A JP 2000-032721 A JP 05-336729 A JP 2009-180921 A

  In FIG. 16, when the diameter of the motor M is D1 and the diameter of the opening 301 that defines the maximum opening amount of the light amount adjusting device 300 is D2, the diameter D3 of the light amount adjusting device 300 is at least (2 × D1 + D2). Become.

  However, in the stepping motor of Patent Document 1 (FIG. 9), the case 103, the bobbin 101, the stator coil 105, and the stator yoke 106 are arranged concentrically on the outer peripheral side of the rotor 109. Will become bigger. For this reason, the diameter D3 of the light quantity adjusting device 300 becomes large, leading to an increase in size.

  Further, in the stepping motor of Patent Document 1, the magnetic flux generated by energizing the stator coil 105 mainly passes through the end face 106a1 of the stator tooth 106a and the end face 106b1 of the stator tooth 106b as shown in FIG. For this reason, the magnetic flux generated by energizing the stator coil 105 does not effectively act on the rotor magnet 111, and it is difficult to increase the motor output.

  In the stepping motor of Patent Document 2 (FIGS. 11 and 12), since the coils 23 and 24 are vertically placed parallel to the rotation axis of the rotor 21, the radial dimension can be reduced, but the motor output is increased. Has a problem that the dimension in the height direction (axial direction) becomes large.

  In the stepping motor of Patent Document 3 (FIG. 13), the coil 38 is vertically placed in parallel with the rotation shaft 36 of the rotor 37 and the nonmagnetic member 30 is interposed, as in Patent Document 2. However, the height dimension (axial direction) becomes larger.

  In the stepping motor of Patent Document 4 (FIG. 14), the radial dimension is small, but the height of the lens barrel base plate 41, the stators 48 and 49, and the coils 45 and 46 for supporting the rotor 47 is required. Become. For this reason, the dimension in the height direction (axial direction) of the stepping motor becomes large, and the magnetic flux generated by the stator magnetic pole does not effectively act on the permanent magnet of the rotor 47, so it is difficult to increase the motor output.

Accordingly, the present invention, it is possible to reduce the size by reducing the size of the radial and axial directions, and an object thereof is to provide an optical amount adjusting device that can be made high motor output.

In order to achieve the above object, a light amount adjusting device of the present invention includes a plurality of aperture blades that adjust the aperture amount of an opening, a drive member that drives the aperture blades, and the aperture blades that are driven by the drive members. of the cam member for regulating the entry of the said opening, and Tei Ruosae member fixed to said cam member is sandwiched between the said diaphragm blade and the drive member are gears coupled to said drive member, A motor mechanism that transmits a driving force to the drive member, the motor mechanism having a rotor, a stator, a first coil, and a second coil, and the rotor has a large number in the circumferential direction. divided by different magnetic poles are formed alternately, said stator is a soft magnetic material, is and formed integrally with the pressing member Tei Rutotomoni, supporting portion, a first magnetic pole portion, and the second magnetic pole The support part has Serial rotatably supports the rotation axis of the rotor, said first magnetic pole portion is formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni, the outer periphery of the rotor and extends toward the part, the second magnetic pole portion, the formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni, toward the outer periphery of the rotor extension and out, wherein the first coil inner peripheral portion wound on the cylindrical shape, said has a first magnetic pole portion of the extending end is inserted into the first magnetic pole portion, the second coils, the inner peripheral portion wound on the cylindrical, characterized in Tei Rukoto is inserted into the second magnetic pole portion from extending end of the second pole portion.

According to the present invention, it is possible to reduce the size by reducing the size of the radial and axial directions, Ru can increase the motor output.

It is a disassembled perspective view for demonstrating the light quantity adjustment apparatus which is an example of embodiment of this invention. It is a disassembled perspective view of a motor mechanism part. It is a perspective view after the assembly of a motor mechanism part. It is sectional drawing which follows the axial direction of a motor mechanism part. It is a top view for demonstrating the operation example of a motor mechanism part. It is a graph which shows the relationship between the rotation position of the rotation member H in the light quantity adjustment apparatus of FIG. It is a perspective view which shows the meshing state of a rotating member and a pinion. It is a disassembled perspective view for demonstrating the light quantity adjustment apparatus which is other embodiment of this invention. It is a longitudinal cross-sectional view which shows typically an example of the conventional stepping motor. It is a fragmentary sectional view which shows typically the state of the magnetic flux which flows from the stator of the stepping motor shown in FIG. It is a disassembled perspective view which shows the other conventional stepping motor. It is sectional drawing which follows the axial direction in the assembly state of the stepping motor shown in FIG. It is sectional drawing which follows the axial direction of the other conventional stepping motor. It is a perspective view which shows the principal part of the other conventional stepping motor. It is a disassembled perspective view of the conventional light quantity adjustment apparatus. It is explanatory drawing for demonstrating the relationship between the diameter of a motor, and the diameter of a light quantity adjustment apparatus.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view for explaining a light amount adjusting device which is an example of an embodiment of the present invention.

  In FIG. 1, the diaphragm blades A to G have a thin blade-shaped blade base portion including a first base portion A <b> 1 to G <b> 1 and a second base portion A <b> 2 to G <b> 2 that have a light shielding property and adjust an opening amount. The diaphragm blades A to G include first shaft portions A3 to G3 provided on one surface of the first base portions A1 to G1, and second shaft portions A4 to G4 (partially not shown) provided on the other surface. And have. The blade base, the first shaft portions A3 to G3, and the second shaft portions A4 to G4 are integrally formed of synthetic resin.

  The rotating member H is a driving member for the diaphragm blades A to G, and is formed in a ring shape having an opening H1 at the center. The rotating member H is provided with holes H2 to H7, a protrusion H8, an arcuate gear H9, and a light shielding part H10.

  The cam member I is a ring-shaped member having an opening I1 in the center, and the amount of the aperture blades A to G driven by the rotating member H to enter the opening 11 is restricted to the substrate I9 of the cam member I. Cam groove portions I2 to I8 are provided.

  This opening portion I1 defines the maximum opening amount of the opening amount adjusted by the diaphragm blades A to G. Therefore, the cam member I also serves as an opening base plate (base portion) that defines the maximum opening amount. Note that the maximum opening amount of the opening amount adjusted by the diaphragm blades A to G may be defined by a member different from the cam member I.

  The pressing member J is a ring-shaped member having an opening J1 at the center. A part of the pressing member J is provided with a motor mounting portion made of a soft magnetic material, and is also used as a stator 1 of a motor mechanism portion 11 to be described later. For this reason, the stator 1 is provided with a support portion 1a in which a support hole for rotatably supporting the rotating shaft 8 of the rotor 6 is formed, a first magnetic pole portion 1b, and a second magnetic pole portion 1c.

  The motor mechanism unit 11 is for driving the rotating member H, and is constituted by a stepping motor and is attached to the motor attachment part of the presser member J. The pinion 12 fixed to the rotating shaft 8 (see FIG. 2) of the rotor 6 with the motor mechanism 11 attached to the presser member J passes through the hole (not shown) of the presser member J and rotates. Engages with H gear part H9. As a result, the rotating member H and the motor mechanism unit 11 are gear-coupled, and the driving force of the motor mechanism unit 11 is transmitted to the rotating member H. The details of the motor mechanism unit 11 will be described later with reference to FIGS.

  The initial position sensor L is attached to the motor mechanism unit 11 and detects whether the rotating member H is in the initial position by detecting an insertion state and a retracted state of the light shielding unit H10 of the rotating member H with respect to the initial position sensor L. judge.

  The holding member J is fixed to the cam member I with the rotating member H and the diaphragm blades A to G interposed therebetween, and thereby serves to prevent the rotating member H and the diaphragm blades A to G from coming off in the optical axis direction. . Here, the protrusion H8 of the rotating member H is rotatably fitted in the opening J1 of the pressing member J. The first shaft portions A3 to G3 of the aperture blades A to G are rotatably fitted in the holes 8b to 8h of the rotating member H, respectively, and the second shaft portions A4 to G4 are cams of the cam member I. The groove portions I2 to I8 are slidably fitted.

  The aperture blades A to G are evenly arranged in the circumferential direction around the optical axis, and the aperture area of the aperture is variable by overlapping the first base portions A1 to G1 and the second base portions A2 to G2 having light shielding properties. Thus, the larger the overlapping area, the smaller the aperture opening area.

[Motor mechanism]
Next, the motor mechanism section 11 will be described in detail with reference to FIGS. 2 is an exploded perspective view of the motor mechanism 11, FIG. 3 is a perspective view after the motor mechanism 11 is assembled, FIG. 4 is a sectional view along the axial direction of the motor mechanism 11, and FIG. 5 is an operation of the motor mechanism 11. It is a top view for demonstrating an example.

  2 to 5, the rotor 6 includes a rotating shaft 8, a core 9, and a permanent magnet 7 made of a magnetic material. The rotating shaft 8 is fitted into the inner peripheral portion of the core 9 by press-fitting or bonding, and the core 9 is fitted into the inner peripheral portion of the permanent magnet 7 by press-fitting or bonding. In addition, you may integrally mold the rotating shaft 8 and the core 9 by using the permanent magnet 7 as a resin molded product.

  The stator 1 is formed integrally with the presser member J by forming a part of the presser member J from a soft magnetic material. The stator 1 includes a support portion 1a having a fitting hole formed in the central portion, a first magnetic pole portion 1b that is integrally or magnetically coupled to the support portion 1a and wound with a coil 3, and a support portion 1a. And a second magnetic pole portion 1c around which the coil 4 is wound. A bearing 2 made of a magnetic material is press-fitted into the fitting hole of the support portion 1a. Here, the coil 3 corresponds to an example of the first coil of the present invention, and the coil 4 corresponds to an example of the second coil of the present invention.

  The lower end 8 b of the rotating shaft 8 of the rotor 6 is rotatably supported by the hole 2 a of the bearing 2, and the upper end 8 a is rotatably supported by the shaft hole 10 a of the cover 10. A washer 5 made of a non-magnetic material is interposed between the bearing 2 and the core 9 of the rotor 6 in order to avoid a magnetic attraction force and an increase in rotational load. The cover 10 is fixed to the stator 1, whereby the motor mechanism unit 11 is configured.

  Next, the components of the motor mechanism unit 11 will be described in detail.

[Stator]
The stator 1 (yoke) is formed integrally with the presser member J by forming a part of the presser member J with a plate material of soft magnetic material (for example, plate thickness t = 0.5 mm ± 0.03 mm). The stator 1 includes a support portion 1a having a fitting hole formed in the central portion, a first magnetic pole portion 1b that is integrally or magnetically coupled to the support portion 1a and wound with a coil 3, and a support portion 1a. And a second magnetic pole portion 1c around which the coil 4 is wound. In this embodiment, the fitting hole of the support part 1a, the 1st magnetic pole part 1b, and the 2nd magnetic pole part 1c are formed by press work.

  The first magnetic pole portion 1b extends toward the outer peripheral portion of the rotor 6 in a direction orthogonal to the rotation axis of the rotor 6, and the inner peripheral portion of the coil 3 is inserted along the extending direction from the extending end. The In such an insertion state, the extending end of the first magnetic pole portion 1 b protrudes from the coil 3 and is disposed close to the outer peripheral portion of the permanent magnet 7.

  Similarly, the second magnetic pole portion 1c extends toward the outer peripheral portion of the rotor 6 in a direction orthogonal to the rotation axis of the rotor 6, and the inner peripheral portion of the coil 4 extends from the extended end along the extending direction. Inserted. In such an insertion state, the extending end of the second magnetic pole portion 1 c protrudes from the coil 4 and is disposed close to the outer peripheral portion of the permanent magnet 7.

  Here, in the present embodiment, the first magnetic pole portion 1b and the line extending in the extending direction of the first magnetic pole portion 1b and the line extending in the extending direction of the second magnetic pole portion 1c intersect each other. A second magnetic pole portion 1c is arranged.

  Specifically, as shown in FIG. 5, the first magnetic pole portion 1 b and the second magnetic pole portion 1 c have θ = (180 / NA + A × 360 / NA) ° with respect to the rotation axis of the rotor 6, that is, ( They are spaced apart from one another in the circumferential direction with an angle of 30 + 60 × A) °. A in the formula is an integer, and in this embodiment, NA = 6, A = 2, and θ = 150 °.

[bearing]
The bearing 2 is made of a magnetic material and has a fitting hole 2a through which the lower end 8b of the rotating shaft 8 passes.

[coil]
The coil 3 is wound in a cylindrical shape, an inner peripheral portion thereof is inserted from the extending end of the first magnetic pole portion 1 b, and a central axis is disposed orthogonal to the rotation axis of the rotor 6. The coil 4 is wound in a cylindrical shape, an inner peripheral portion thereof is inserted from the extending end of the second magnetic pole portion 1 c, and a central axis is disposed orthogonal to the rotation axis of the rotor 6.

[Washer]
The washer 5 is made of a nonmagnetic material and is disposed between the support portion 1 a of the stator 1 and the rotor 6. Thereby, a slight magnetic gap is formed between the support portion 1a and the rotor 6 to prevent the stator 1 and the rotor 6 from being attracted by an axial magnetic force.

[permanent magnet]
The permanent magnet 7 is divided into multiple parts in the circumferential direction (in this embodiment, 6 parts: see FIG. 5), and N poles and S poles are alternately magnetized. The permanent magnet 7 can be made extremely thin in the radial direction by forming a plastic magnet material by injection molding or the like.

  The inner peripheral surface of the permanent magnet 7 has a weak magnetization distribution as compared with the outer peripheral surface, or is not magnetized at all, or is in a range opposite to the outer peripheral surface, that is, the outer peripheral surface is an S pole. The inner peripheral surface of is one of those magnetized to the N pole.

[Axis of rotation]
The rotating shaft 8 is made of a soft magnetic material and is fixed to the inner peripheral portion of the permanent magnet 7. The upper end 8a of the rotating shaft 8 is rotatably fitted in the shaft hole 10a of the cover 10, and the lower end 8b is rotated in the fitting hole 2a of the bearing 2 fitted in the fitting hole of the support portion 1a of the stator 1. Can be fitted. A pinion 12 is fixed to the lower end 8b of the rotating shaft 8 protruding from the fitting hole 2a of the bearing 2.

[core]
The core 9 is made of a soft magnetic material, and constitutes an inner yoke with respect to the outer yoke constituted by the first magnetic pole portion 1b and the second magnetic pole portion 1c of the stator 1, and the first magnetic pole portion 1b and the second magnetic pole portion 1c. A magnetic circuit is formed together with the two magnetic pole portions 1c.

[cover]
The cover 10 is fixed to the stator 1 by, for example, adhesion or screwing to cover the rotor 6.

[Operation of motor mechanism]
Next, an operation example of the motor mechanism unit 11 will be described with reference to FIG.

  In FIG. 5, when the coil 4 is energized, the second magnetic pole portion 1c of the stator 1 is excited, and one of the magnetic poles divided in the circumferential direction of the permanent magnet 7 of the rotor 6 becomes the first magnetic pole. The rotor 6 stops at a position facing the second magnetic pole portion 1c (initial energization).

  For example, when the coil 4 is energized in the positive direction, the second magnetic pole portion 1c is excited to the S pole, and the rotor 6 stops at a position where the N pole of the permanent magnet 7 faces the second magnetic pole portion 1c. .

  As the magnetic path, the magnetic flux generated by energizing the coil 4 passes through the second magnetic pole portion 1c of the stator 1, the air gap between the second magnetic pole portion 1c and the permanent magnet 7, the permanent magnet 7 and the core 9. It passes through to the support part 1a.

  When the coil 3 is energized in the positive direction while the coil 4 is energized in the positive direction, the first magnetic pole portion 1b is also excited to the S pole, and the rotor 6 rotates in the clockwise direction of FIG. The first and second magnetic pole portions 1b and 1c move to positions where the N poles of the permanent magnet 7 are evenly opposed to each other.

  In this way, the rotor 6 can be rotated by a certain angle by repeating the one-phase excitation and the two-phase excitation such that the coil 4 is energized in the positive direction → the coil 3 is energized in the positive direction → the coil 3 is de-energized. Yes (stepping motor drive by 1-2 phase excitation).

[Relationship between rotating member and pinion]
FIG. 6 is a graph showing the relationship between the rotational position of the rotating member H and the aperture opening area in the light quantity adjusting device of FIG. 1, and FIG. 7 is a perspective view showing the meshing state of the rotating member H and the pinion 12.

  In FIG. 6, when the initial position sensor L detects the insertion state of the light shielding portion H10 of the rotating member H, the aperture blades A to G are outside the opening I1 along the cam groove portions I2 to I8 of the cam member I. The retraction position is such that the maximum opening is not shielded.

  From this retracted position, the motor mechanism unit 11 drives the pinion 12 in the direction of the arrow CCW in FIG. 7 and drives the rotating member H in the direction of the arrow CW for a predetermined step (3 steps in this example). When the rotary member H is driven in the arrow CW direction, the aperture blades A to G shield the opening I1 along the cam groove portions I2 to I8 of the cam member I to form a predetermined opening area (shielding position). .

  Here, the first cam region is within 3 steps from the initial position where the initial position sensor L detects the insertion state of the light shielding portion H10 of the rotating member H, and the aperture blades A to G are in the above retracted positions. Means a range. The second cam region means a range in which the aperture blades A to G exceeding three steps from the initial position are in the shielding position.

  In FIG. 7, the gear portion H9 of the rotating member H includes a first gear portion H9-1 and a second gear portion H9-2 that have different axial thicknesses (the other number of teeth, pitch, etc. are the same). A first gear portion (hereinafter referred to as a thin gear portion) H9-1 having a smaller axial thickness meshes with the pinion 12 when the aperture blades A to G are in the first cam region. On the other hand, a second gear portion (hereinafter referred to as a thick gear portion) H9-2 having a larger axial thickness meshes with the pinion 12 when the aperture blades A to G are in the second cam region.

  Here, since the pinion 12 has a conical shape with a small diameter toward the tip side, when the pinion 12 meshes with the thin gear portion H9-1, the pinion 12 meshes with a small-diameter portion of the tip portion, thereby increasing backlash. On the other hand, when the pinion 12 meshes with the thick gear portion H9-2, the meshing is performed at the large-diameter portion at the root, and the backlash is smaller than the meshing at the small-diameter portion. In other words, if the backlash amount when the pinion 12 meshes with the thin gear portion H9-1 is Y1, and the backlash amount when the pinion 12 meshes with the thick gear portion H9-2 is Y2, then Y1> Y2.

[Light intensity adjustment operation]
Next, an operation example when the light amount adjusting device of the present embodiment is applied to a digital camera will be described.

  In the following description, a state where the initial position sensor L detects the insertion of the light shielding portion H10 of the rotating member H is defined as an initial position.

  In the case of still image shooting, this initial position is always set as the start position. The motor mechanism unit 11 is driven to an arbitrary aperture position so that a predetermined aperture value is obtained from the initial position. The pinion 12 is rotated by rotating the motor mechanism portion 11 counterclockwise in FIG. 1 (CCW direction in FIG. 7), and the pinion 12 is engaged with the gear portion H9 of the rotating member H. In the clockwise direction (CW direction in FIG. 7).

  Therefore, when the diaphragm blades A to G are in the retracted position and are in the first cam region of the cam member I, the small diameter portion of the tip end portion of the pinion 12 meshes with the thin gear portion H9-1 portion of the rotating member H. Becomes larger. As a result, even if there is a variation in the component shape accuracy of each component, the driving load does not increase, a smooth start-up can be performed, and a subsequent narrowing operation can be performed to a predetermined aperture value thereafter.

  In this embodiment, the pinion 12 is set so that the pinion 12 meshes with the thin gear portion H9-1 of the rotating member H within 3 steps from the initial position. However, the present invention is not limited to 3 steps. Two steps may be used. Further, it is not necessary to increase the backlash over the entire first cam region. That is, if a large backlash is ensured at least in the movement start range (only a predetermined range in the vicinity of the initial position), a smooth start can be performed, and a high-speed narrowing operation can be performed up to a predetermined aperture value thereafter.

  And after starting smoothly, the motor mechanism part 11 is further driven in the same direction, and the rotating member H is rotated in the clockwise direction of FIG. 1 (CW direction of FIG. 7). Then, since the first shaft portions A3 to G3 of the aperture blades A to G are fitted in the hole portions H2 to H7 of the rotating member H, the aperture blades A to G are respectively connected to the first shaft portions A3 to G3. With the operation, the second shaft portions A4 to G4 move along the cam groove portions I2 to I8 of the cam member I and move to the shielding position. This is the movement in the second cam region that forms the predetermined aperture value.

  In the second cam region, the large-diameter portion at the base of the pinion 12 in the axial direction meshes with the thick gear portion H9-2 of the rotating member H, and the pressing force in the radial direction becomes larger than meshing at the small-diameter portion. Backlash is reduced. If the backlash is small, the drive load may increase if there is variation in the part shape accuracy of each part. However, the rotation of the rotating member H has already been sufficiently accelerated in the second cam region. It will not be. As a result, at the time of still image shooting, a high-speed narrowing operation with a small release time lag can be performed.

  When the diaphragm blades A to G are returned to the initial positions after the still image shooting is finished, the control unit (not shown) that controls the rotation amount of the motor mechanism unit 11 causes the motor mechanism unit 11 to be the aperture direction (shielding position). Drive in the opposite direction. In this case, the driving is started from the second cam area, but it is not necessary to drive at a high speed since the photographing is finished. For this reason, even if the backlash between the large-diameter portion of the pinion 12 and the thick gear portion H9-2 of the rotating member H is small, and there is a variation in the part shape accuracy of each part and the driving load is increased, high-speed driving is possible. Since it is not performed, the operation does not become unstable.

  Next, at the time of moving image shooting, it is always driven in the second cam region, and it is necessary to continuously change the aperture value in accordance with the field luminance that changes every moment. Since it is rare that the field brightness changes rapidly, it is necessary to increase the accuracy and miniaturization of the aperture value although high speed is not desired for changing the aperture value. Here, in the second cam region, the pinion 12 meshes with the thick gear portion H9-2 of the rotating member H, so the backlash is reduced. Therefore, a highly accurate and fine aperture adjustment operation is possible.

  Further, by forming the first gear portion H9-1 and the second gear portion H9-2 having different axial thicknesses on the gear portion H9 of the rotating member H, the backlash amount A1> first in the first cam region. The backlash amount A2 in the second cam region is configured.

  In addition, it is conceivable that the backlash amount can be varied by changing the shift amount of the gear portion H9 while keeping the axial thickness of the gear portion H9 of the rotating member H in the second cam region constant. That is, it can be realized by [the amount of shift of the gear portion of the rotating member H when in the first cam region] <[the amount of shift of the gear portion of the rotating member H when in the second cam region]. It is.

  As described above, in the present embodiment, the stator 1 of the motor mechanism 11 is formed on a part of the presser member J constituting the light amount adjusting device, and the first and second magnetic pole portions 1b and 1c of the stator 1 are formed. The coils 3 and 4 are attached so that the central axis thereof is orthogonal to the rotational axis of the rotor 6. For this reason, when a large torque is required, the coil space can be increased without increasing the axial dimension of the motor mechanism section 11. Thereby, while being able to make small the axial direction dimension of the light quantity adjustment apparatus containing the motor mechanism part 11, the motor output of the motor mechanism part 11 can be made high.

  Moreover, in this embodiment, since the stator 1 is formed by a part of the pressing member, the axial dimension of the light amount adjusting device including the motor mechanism 11 can be further reduced, and low cost can be realized. Can do.

  Furthermore, in this embodiment, since the 1st magnetic pole part 1b and the 2nd magnetic pole part 1c are formed in the single stator 1, the positional accuracy of the 1st magnetic pole part 1b and the 2nd magnetic pole part 1c is used. Can be increased.

  Furthermore, in the present embodiment, the first magnetic pole portion 1b and the second magnetic pole portion 1c are arranged at an angle of θ = (30 + 60 × A) ° with respect to the rotation axis of the rotor 6, so The magnetic pole part 1b and the second magnetic pole part 1c can be arranged in the same plane. For this reason, the rotor 6 can reduce the dimension of an axial direction.

  Further, since the coil 3 and the coil 4 are arranged so that the central axis of the coil 3 and the central axis of the coil 4 are orthogonal to the rotation axis of the rotor 6, the motor can be reduced in the axial direction of the rotor 6. Is possible.

  Further, in the present embodiment, the first magnetic pole part 1 b and the second magnetic pole part 1 c are arranged on the same plane orthogonal to the rotation axis of the rotor 6. Accordingly, since the magnetic flux acts on the same portion of the permanent magnet 7 of the rotor 6 where the two magnetic pole portions 1b and 1c are rotated, it is possible to ensure stable rotation without being adversely affected by variations in magnetization. .

  Furthermore, in the present embodiment, the magnetic flux generated by energizing the coil 4 generates the second magnetic pole portion 1c of the stator 1, the air gap between the second magnetic pole portion 1c and the permanent magnet 7, the permanent magnet 7, and the core. A magnetic path is formed so as to pass through 9 to the support portion 1a. Thereby, the magnetic flux by coil excitation can be made to act on the permanent magnet 7 efficiently, and the motor output of the motor mechanism part 11 can be made high.

  In this embodiment, the maximum diameter of the motor mechanism 11 is determined by the magnet diameter of the permanent magnet 7. Therefore, if the diameter of the permanent magnet 7 is the same, the diameter of the motor mechanism 11 compared to the horseshoe-shaped yoke type. The direction dimension can be reduced. The magnet diameter of the permanent magnet 7 is a major factor for securing the torque, and it is basically considered that the torque is proportional to the square of the magnet diameter of the permanent magnet 7 (two factors of circumferential area and radius).

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

  For example, in the above-described embodiment, the case where the stator 1 is formed on a part of the pressing member J is illustrated, but instead, the stator 1 is attached to a part of the substrate I9 of the cam member I as shown in FIG. You may form and attach the motor mechanism part 11. FIG.

  In this case, a plurality of aperture blades A˜ are formed by simultaneously forming the support portion 1a, the first magnetic pole portion 1b, the second magnetic pole portion 1c, the opening portion I1, and the cam groove portions I2 to I8 on the substrate I9. The aperture accuracy of the aperture opening regulated by G is improved.

DESCRIPTION OF SYMBOLS 1 Stator 1b 1st magnetic pole part 1c 2nd magnetic pole part 3, 4 Coil 6 Rotor 11 Motor mechanism part A-G Diaphragm blade H Rotating member I Cam member J Holding member

Claims (4)

A plurality of aperture blades for adjusting the opening amount of the opening;
A drive member for driving the diaphragm blades;
A cam member for restricting the amount of the diaphragm blades driven by the drive member from entering the opening;
And Tei Ruosae member fixed to said cam member is sandwiched between the said diaphragm blade and the drive member,
It said drive member being a gear connected to, and a motor mechanism for transmitting a driving force to the drive member,
The motor mechanism has a rotor, a stator, a first coil, and a second coil,
The rotor has a multi-divided in different magnetic poles in the circumferential direction is formed alternately,
The stator is a soft magnetic material, and the pressing member is formed integrally with the imperial Rutotomoni, the support portion has a first magnetic pole portion, and the second magnetic pole portion,
The supporting portion rotatably supports the rotary shaft of the rotor,
The first magnetic pole portion, the formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni extends out toward the outer periphery of the rotor,
Said second magnetic pole portion, the formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni extends out toward the outer periphery of the rotor,
It said first coil, the inner peripheral portion wound on the cylindrical can, is inserted into the first magnetic pole portion from extending end of the first magnetic pole portion,
Said second coil, the light quantity adjusting device inner peripheral portion wound on the cylindrical, characterized in Tei Rukoto is inserted into the second magnetic pole portion from extending end of the second pole portion. A plurality of aperture blades for adjusting the opening amount of the opening;
A drive member for driving the diaphragm blades;
A cam member for restricting the amount of the diaphragm blades driven by the drive member from entering the opening;
And Tei Ruosae member fixed to said cam member is sandwiched between the said diaphragm blade and the drive member,
It said drive member being a gear connected to, and a motor mechanism for transmitting a driving force to the drive member,
The motor mechanism has a rotor, a stator, a first coil, and a second coil,
The rotor has a multi-divided in different magnetic poles in the circumferential direction is formed alternately,
The stator is a soft magnetic material, and said cam member is formed integrally with the imperial Rutotomoni, the support portion has a first magnetic pole portion, and the second magnetic pole portion,
The supporting portion rotatably supports the rotary shaft of the rotor,
The first magnetic pole portion, the formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni extends out toward the outer periphery of the rotor,
Said second magnetic pole portion, the formed in the position and different positions of the support portions in the direction of the axis of rotation of the rotor Tei Rutotomoni extends out toward the outer periphery of the rotor,
It said first coil, the inner peripheral portion wound on the cylindrical can, is inserted into the first magnetic pole portion from extending end of the first magnetic pole portion,
Said second coil, the light quantity adjusting device inner peripheral portion wound on the cylindrical, characterized in Tei Rukoto is inserted into the second magnetic pole portion from extending end of the second pole portion. Wherein the cam member, and said opening, said cam groove to stop restricting the entry of the said opening of the blade the light quantity adjusting device according to claim 1, wherein the Tei Rukoto formed integrally . The first magnetic pole portion and the second magnetic pole portion, the light quantity adjusting device according to any one of claims 1 to 3, characterized in Tei Rukoto formed by press working.

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