JP2009268166A - Spindle motor and disk drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle motor having a rotor portion stably rotated, and to provide a disk drive device. <P>SOLUTION: A shielding member 27 of the spindle motor 1 has a third planar section 273 so formed that the axial height of its inner circumferential surface is uniform in the circumferential direction. The third planar section is positioned inside a first planar section 271 in the radial direction and inside a second planar section 272 adjoining to the first planar section 271 in the circumferential direction, in the radial direction. The axial height of the inner circumferential surface 273a of the shielding member 27 opposed to the outer circumferential surface 17a of a rotor magnet 17 with a gap is uniform in the circumferential direction. Therefore, magnetic bias is stabilized when the motor 1 is rotationally driven and this stabilizes rotation of the rotor portion 13 and suppresses the occurrence of trouble, such as PES (Positioning Error Signal). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spindle motor and a disk drive device including the spindle motor.

  In recent years, along with the downsizing and thinning of recording disk drive devices such as magnetic disks and optical disks used in personal computers and car navigation systems, there has been an increasing demand for downsizing, in particular, thinning of motors incorporated therein. As this type of motor, there are an inner rotor type in which the rotor rotates on the radially inner side of the stator and an outer rotor type in which the rotor rotates on the outer side in the radial direction of the stator. The motor will be described.

  In the conventional inner rotor type spindle motor, a magnetic flux is generated in the stator by energizing the stator from an external power source via a flexible circuit board (hereinafter referred to as FPC (Flexible Printed Circuit)). A rotational torque is generated by the magnetic interaction with the magnet and is driven to rotate.

  A shield member made of a magnetic shield plate is disposed on the upper side of the stator to prevent a large amount of magnetic flux generated by the stator mainly during rotational driving from flowing in a region above the shield member.

  The shape of the shield member has a two-stage configuration in which stepped height surfaces are provided in the circumferential direction by pressing or the like. This is because the surface corresponding to the swing operation area of the head portion is lowered so that the head portion can be positioned above the shield member so that the head portion can be positioned above the shield member when the head portion swings. I have to.

  Such a conventional spindle motor is disclosed in Patent Document 1, for example.

International Publication No. 2000/62404

  However, since the shield member included in the conventional spindle motor has a two-stage configuration in the circumferential direction, the inner circumferential surface of the shield member facing the rotor magnet via a gap in the radial direction is stepped and uneven. Therefore, the magnetic bias at the time of motor rotation driving is not stable, and the rotation of the rotor portion becomes unstable, so that the head cannot follow the track of the recording disk and the information writing to the recording disk becomes impossible. Problems such as reading failure (so-called tracking error), Puretone (abnormal noise due to resonance between stator and rotor), RRO (Repeatable Run Out: Shake of the synchronous component of the shaft during motor operation), etc. It sometimes occurred.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a spindle motor and a disk drive device that can stably rotate a rotor portion in order to solve the above problems.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the shield member is configured by a plane extending in a direction substantially perpendicular to the central axis, and a first plane portion corresponding to a swing operation region of the head portion; A second planar portion that is adjacent to the first planar portion in the circumferential direction and is positioned above the first planar portion with a direction along the central axis as a vertical direction; the second planar portion; and the first planar portion. And a third plane part that is located below the second plane part and that has a uniform axial height in the circumferential direction.

  The invention according to claim 2 is the spindle motor according to claim 1, wherein the stator further includes a substantially annular core back that connects radially outer ends of the plurality of teeth portions in the circumferential direction. A plurality of electrical connection portions arranged between the plurality of adjacent tooth portions, to which the conductive wires from the stator are electrically connected, and the radially outer ends of the plurality of electrical connection portions are connected to each other. A flexible printed circuit board having a substantially arc-shaped main body formed extending in the circumferential direction, wherein at least the main body of the flexible printed circuit board has a lower surface of the second planar portion and an axial direction of the coil. It is arranged between them.

  According to a third aspect of the present invention, in the spindle motor according to the second aspect, the width obtained by combining the radial width of the main body portion and the radial width of the electrical connection portion of the flexible printed board is the shield. It corresponds to or smaller than the radial width of the second flat portion of the member.

  According to a fourth aspect of the present invention, in the spindle motor according to any one of the first to third aspects, the first flat portion of the shield member has a substantially fan shape that radially expands from a radially inner side to a radially outer side. It is characterized by comprising.

  A fifth aspect of the present invention is the spindle motor according to any one of the first to fourth aspects, wherein the first flat surface portion and the third flat surface portion have the same axial height. .

  The invention according to claim 6 is the spindle motor according to any one of claims 1 to 5, characterized in that an insulating layer is coated on a surface of the shield member on the coil side.

  The invention according to claim 7 is a disk drive device for rotating a disk, wherein the base member, the spindle motor according to any one of claims 1 to 6 fixed inside the base member, and the A head unit that reads and / or writes information from and to a disk, and a moving unit that moves the head unit along a plane of the disk.

  According to invention of Claims 1-7, the said shield member is comprised from the plane extended in the substantially perpendicular | vertical direction to the said central axis, The 1st plane part corresponding to the swing operation area | region of the said head part, The said 1st A second plane portion that is adjacent to the one plane portion in the circumferential direction and is located above the first plane portion with the direction along the central axis as the vertical direction; and the diameters of the second plane portion and the first plane portion And a third plane portion that is disposed on the inner side in the direction and is located below the second plane portion and has a uniform axial height in the circumferential direction. With this configuration, the axial height of the inner circumferential surface of the shield member facing the outer circumferential surface of the rotor magnet with a gap is uniform in the circumferential direction, and the magnetic bias is stable when the motor is driven to rotate. Thus, the rotation of the rotor portion is stabilized, and the occurrence of problems such as PES, Puretone, RRO, etc. can be suppressed.

  In particular, according to the invention described in claim 2, at least the main body portion of the flexible printed circuit board is disposed between the lower surface of the second flat surface portion and the axial direction of the coil. By adopting such a configuration, the spindle motor can be thinned in the axial direction, and the spindle motor can be thinned and miniaturized.

  In particular, according to the sixth aspect of the present invention, the insulating layer is coated on the surface of the shield member on the coil side. Since the shield member is made of a conductive material, such a configuration can prevent the shield member and the coil or the flexible printed board from being short-circuited due to metal contact, and as a result, a highly reliable spindle. A motor can be provided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the description of the present invention, when the positional relationship and direction of each member are described in the upper, lower, left and right directions, the positional relationship and direction in the drawings are only shown, and the positional relationship and direction when incorporated in an actual device are shown. is not. In the following description, for convenience of description, along the central axis L, the disk 4 side is “upper” and the coil 24 side is “lower”.

<1. Configuration of disk drive>
FIG. 1 is a longitudinal sectional view of a disk drive device 2 provided with a spindle motor 1 according to an embodiment of the present invention. FIG. 2 is an upper plan view for explaining the internal structure of the disk drive device 2. The disk drive device 2 is a hard disk device that reads information from and writes information to the magnetic disk 4 while rotating the two magnetic disks 4. As shown in FIG. 1, the disk drive device 2 mainly includes an apparatus housing 3, two recording disks (hereinafter simply referred to as "disks") such as a magnetic disk and an optical disk, and a spindle that rotates the disk at a constant speed. The head unit 6 that reads and / or writes information to and from the motor 1 and the disk 4, supports the head unit, and rotates the carriage unit 7 and the carriage unit 7 that can rotate around the rotation axis. Is provided with a rocking portion 8 for positioning the disk 4 to read and / or write information.

  The device housing 3 includes a cup-shaped first housing member 31 and a plate-shaped second housing member 32. The first housing member 31 has an opening at the top, and the second housing member 32 is joined to the first housing member 31 so as to cover the opening at the top of the first housing member 31. Two disks 4, the access unit 5, the stator 22, and the spindle motor 1 are accommodated in the internal space 33 of the apparatus housing 3 surrounded by the first housing member 31 and the second housing member 32. The internal space 33 of the device housing 3 is a clean space with less dust and dirt.

  A concave substantially circular base 311 is formed on the bottom surface of the first housing member 31, and the spindle motor 1 and the stator 22 are installed on the base 311. A through hole 311 a that penetrates the base 311 along the central axis L is formed at the center of the base 311. Further, on the outer peripheral side (the outer peripheral side with respect to the central axis L. The same applies hereinafter) from the through hole 311a of the base 311, a substantially cylindrical holder protruding in the axial direction (the direction along the central axis L; the same applies hereinafter). A portion 311b is formed. In the present embodiment, the first housing member 31 and the base 311 are formed of a single member, but the first housing member 31 and the base 311 may be separate.

  Each of the two disks 4 is a disk-shaped information recording medium having a hole in the center. Each disk 4 is mounted on the rotor hub 15 of the spindle motor 1 and stacked in parallel with each other via a spacer 41.

  On the other hand, the access unit 5 is fixed to the four head units 6 facing the upper and lower surfaces of the two disks 4, the carriage unit 7 that supports each head 6, and the bottom surface of the first housing member 31. And a rocking portion 8 having 7.

  The carriage unit 7 includes a spring arm 71 that supports the head unit 6 at the tip thereof, and a mounting arm 72 that fixes the spring arm 71, and is rotatably supported by the rotation shaft 9. On the other hand, the voice coil motor 10 provided on the opposite side of the mounting arm 72 is driven to swing about the rotary shaft 9. The voice coil motor 10 includes a coil 101 that rotates integrally with the carriage unit 7, and magnets 102 a and 102 b that are fixedly disposed inside the apparatus housing 3 so as to sandwich the coil 101 in the axial direction. Is done.

  The access unit 5 causes the four carriage units 7 to swing along the disk 4 by driving the voice coil motor 10 by passing an electric current through the coil 101, and the four head units 6 are moved to the required positions of the disk 4. To read and write information on the recording surface of each rotating disk 4. By controlling the direction of the current flowing through the coil 101, the carriage unit 7 can be urged in the direction of arrow C or urged in the direction of arrow D. The head unit 6 may perform only one of reading and writing of information with respect to the recording surface of the disk 4.

<2. Spindle motor configuration>
Next, a detailed configuration of the spindle motor 1 will be described. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a partial vertical cross-sectional view of the spindle motor 1 for explaining the radial dynamic pressure bearing portion and the thrust dynamic pressure bearing portion. As shown in FIG. 3, the spindle motor 1 according to this embodiment includes a bearing housing 11 fixed to a base 311, a sleeve 12 fixed to an inner peripheral surface 11 b of the bearing housing 11, and rotation by the sleeve 12. And a rotor portion 13 that is freely supported.

  The hollow cylindrical bearing housing 11 includes a plate-like counter plate 14 that closes the lower portion of the bearing housing 11. A notch portion 11a is formed in the inner edge portion of the lower flat surface portion of the bearing housing 11, and the outer end portion of the counter plate 14 is applied thereto and bonded and fixed thereto. The bearing housing 11 is made of, for example, stainless steel or a resin member.

  A cylindrical sleeve 12 having a bearing hole penetrating in the axial direction at the center is fixed to the inner peripheral surface 11b of the bearing housing 11 by means such as adhesion. The sleeve 12 is formed from a porous sintered body impregnated with oil, and the material thereof is not particularly limited. The sleeve 12 is molded and sintered using various metal powders, metal compound powders, and nonmetal powders as raw materials. used. Examples of the raw material include Fe—Cu, Cu—Sn, Cu—Sn—Pb, and Fe—C. The bearing housing 11 and the sleeve 12 can be formed from, for example, copper or a copper alloy. In this embodiment, the counter plate 14 is fixed below the hollow cylindrical bearing housing 11 and the opening is closed. However, a bearing housing in which they are integrated, that is, a cup-shaped bearing housing is utilized. It is also possible.

  The rotor portion 13 that is a rotating member includes a shaft 16 that is disposed along the central axis L, a thrust plate 18 that projects radially outward from the vicinity of the lower end portion of the shaft 16, and an approximately formed integrally with the shaft 16. And a cup-shaped rotor hub 15.

  The rotor hub 15 has a shape that expands in the radial direction around the shaft 16 that is the central axis L in the spindle motor 1, and a through-hole 15 a centering on the central axis L is formed at the center thereof. 16 is fixed. The rotor hub 15 will be described in more detail with respect to the shape thereof. The rotor hub 15 includes a first cylindrical portion 151 fixed to the outer peripheral surface of the shaft 16, a flat plate portion 152 extending from the upper end portion of the first cylindrical portion 151 toward the radially outer side, And a second cylindrical portion 153 depending from the outer peripheral edge of the flat plate portion 152. The outer peripheral surface 15 b of the second cylindrical portion 153 serves as a contact surface that contacts the inner peripheral portion (the inner peripheral surface or the inner peripheral edge) of the disk 4. Further, a base portion 154 (disk mounting portion) is formed near the lower end portion of the second cylindrical portion 153 so as to protrude outward in the radial direction and whose upper surface becomes a flange surface 15c on which the disk 4 is mounted. . Such a rotor hub 15 is made of, for example, stainless steel. Further, an annular rotor magnet 17 is fixed to the outer peripheral surface of the second cylindrical portion 153 below the base portion 154 with an adhesive or the like.

  The rotor magnet 17 is a so-called radial anisotropy or isotropic neodymium magnet in which N poles and S poles are alternately arranged in the circumferential direction, and the magnetic flux directions of these magnetic poles substantially coincide with the radial direction of the rotor magnet 17. is there. The rotor magnet 17 is fixed to the rotor hub 15 so as to have a certain gap in the radial direction between the outer peripheral surface 17a and a tip portion of a tooth portion 231 described later.

  The two disks 4 are stacked in a horizontal posture on the flange surface 15 c of the rotor hub 15. That is, the lower disk 4 is placed on the flange surface 15 c, and the other disk 4 is placed on the upper part via the spacer 41. The upper surface of the upper disk 4 is pressed and fixed by a pressing member 155 attached to the flat plate portion 152 of the rotor hub 15. With such a configuration, the disk 4 is sandwiched between the flange surface 15 c of the rotor hub 15 and the pressing member 155 and can rotate integrally with the rotor hub 15.

  The shaft 16 is a substantially columnar member disposed along the central axis L. The first cylindrical portion 151 of the rotor hub 15 is opposed to the outer peripheral surface of the shaft 16 in the radial direction, and the lower end surface of the shaft 16 is configured to be slightly below the lower surface of the sleeve 12. Yes.

  A thrust plate 18 is fixed near the lower end of the shaft 16 so as to project radially outward from the outer peripheral surface of the shaft 16. The upper surface 18a and the lower surface 18b of the thrust plate 18 are opposed to the lower surface 12a of the sleeve 12 and the upper surface 14a of the counter plate 14 in the axial direction with a small gap therebetween, and the outer peripheral surface 18c thereof is in diameter with the inner peripheral surface 11b of the bearing housing 11. It faces in the direction through a minute gap. The material of the thrust plate 18 can be selected as appropriate from the required mechanical strength, dimensional stability, etc. However, since it is fixed near the lower end of the shaft 16 and rotates integrally with the shaft 16, it is about the same as the shaft 16. A material having a thermal expansion coefficient of Note that the shaft 16 and the thrust plate 18 may be formed of a single member.

  In such a configuration, a minute gap between the upper surface 11 c of the bearing housing 11 and the upper surface 12 c of the sleeve 12 and the lower surface 152 a of the flat plate portion 152 of the rotor hub 15, and the outer peripheral surface 151 a of the first cylindrical portion 151 of the rotor hub 15 A minute gap between the inner peripheral surface 12b of the sleeve 12, a minute gap between the lower surface 12a of the sleeve 12 and the upper surface 18a of the thrust plate 18, a minute gap between the upper surface 14a of the counter plate 14 and the lower surface 18b of the thrust plate 18; Are connected to each other, and the lubricating oil 19 is held as a lubricating fluid without interruption in the minute gaps communicating with each other.

  Next, the bearing structure will be described with reference to FIG.

  A radial hydrodynamic bearing that supports a radial load is provided in a minute gap between a rotor hub radial bearing surface located radially outside the first cylindrical portion 151 of the rotor hub 15 and a sleeve radial bearing surface of the sleeve 12 opposed thereto. A herringbone-shaped radial dynamic pressure groove array 20 that induces fluid dynamic pressure in the lubricating oil 19 during relative rotation is formed on at least one of the shaft radial bearing surface and the sleeve radial bearing surface.

  In the present embodiment, the inner circumferential surface 12b of the sleeve 12 is formed with herringbone-shaped radial dynamic pressure groove rows 20a and 20b having a "<" shape in the vertical direction and spaced apart in the axial direction.

  When the rotor hub 15 and the shaft 16 are integrally rotated with respect to the sleeve 12 by the rotation of the motor 1, the lubricating oil 19 filled in the minute gaps is fluidized by the pumping action of the radial dynamic pressure groove rows 20 a and 20 b. The rotor hub 15 fixed to the shaft 16 by inducing dynamic pressure is supported in the radial direction while being out of contact with the sleeve 12, and is rotatably supported with respect to the sleeve 12.

  The radial dynamic pressure groove array 20 is not limited to the herringbone shape, but may be a spiral shape or a tapered land shape, and may function as a fluid dynamic pressure bearing. In the present embodiment, the radial dynamic pressure groove array 20 is formed on the sleeve radial bearing surface, but may be formed on the outer peripheral surface 151a of the first cylindrical portion 151 of the rotor hub 15 that is the rotor hub radial bearing surface. . In the present embodiment, the first cylindrical portion 151 of the rotor hub 15 is sandwiched between the sleeve 12 and the shaft 16. However, the first cylindrical portion 151 of the rotor hub 15 is not present, that is, the sleeve thrust. It is also possible to provide a shaft thrust bearing surface as a surface facing the bearing surface.

  In addition, a thrust bearing portion is provided in a minute gap between the rotor hub thrust bearing surface located below the flat plate portion 152 of the rotor hub 15 and the bearing housing thrust bearing surface located above the bearing housing 11 facing the rotor hub thrust bearing surface. At least one of the rotor hub thrust bearing surface and the bearing housing thrust bearing surface is formed with a spiral-shaped thrust dynamic pressure groove array 21a that induces fluid dynamic pressure in the lubricating oil 19 during relative rotation.

  Similarly, a thrust bearing portion is provided in a minute gap between a sleeve thrust bearing surface located below the sleeve 12 and a thrust plate thrust bearing surface located above the thrust plate 18 facing the sleeve thrust bearing surface. At least one of the last bearing surface and the thrust plate thrust bearing surface is formed with a spiral-shaped thrust dynamic pressure groove array 21b that induces fluid dynamic pressure in the lubricating oil 19 during relative rotation.

  In the present embodiment, a thrust dynamic pressure groove array for generating fluid dynamic pressure in the lubricating oil 19 filled between the upper surface 11 c of the bearing housing 11 and the upper surface 12 c of the sleeve 12 is formed on the upper surface 11 c of the bearing housing 11. 21a is formed radially outward from the central axis side in the radial direction. The lower surface 12a of the sleeve 12 also has a thrust dynamic pressure groove array 21b for generating fluid dynamic pressure in the lubricating oil 19 filled between the lower surface 12a of the sleeve 12 and the upper surface 18a of the thrust plate 18. It is formed radially outward from the side.

  Accordingly, the rotor portion 13 is pressed in the vertical direction by the floating action on the rotor portion 13 by the thrust dynamic pressure groove row 21a and the push-down action on the thrust plate 18 by the thrust dynamic pressure groove row 21b. And in the position where these dynamic pressures balance, the rotation floating position of the rotor part 13 is stabilized. By forming the thrust dynamic pressure groove rows 21a and 21b, the shaft supporting force generated in the thrust dynamic pressure groove rows 21a and 21b acts in cooperation from the opposite directions in the axial direction. Can be stably supported.

  In the present embodiment, the thrust dynamic pressure groove rows 21a and 21b are both formed with spiral grooves, but herringbone-shaped grooves (herring bones) are formed in one or both of the thrust dynamic pressure groove rows 21a and 21b. It is also possible to form a groove).

  In this embodiment, the thrust dynamic pressure groove row 21a is formed on the bearing housing thrust bearing surface, and the thrust dynamic pressure groove row 21b is formed on the sleeve thrust bearing surface. However, the thrust dynamic pressure groove row 21a is formed on the rotor hub thrust bearing surface. In addition, the thrust dynamic pressure groove array 21b may be formed on the thrust plate thrust bearing surface. Further, in the present embodiment, the thrust bearing surface facing the rotor hub thrust bearing surface is the bearing housing thrust bearing surface positioned above the bearing housing 11, but the thrust bearing surface facing the rotor hub thrust bearing surface is also the same. The thrust dynamic pressure groove array 21 a may be formed on the sleeve thrust bearing surface located above the sleeve 12. At this time, the thrust dynamic pressure groove array 21a may be formed on either one or both of the bearing housing thrust bearing surface and the sleeve thrust bearing surface.

<3. Structure of stator>
Next, the stator 22 fixed to the base 311 of the first housing member 31 will be described with reference to FIG. The stator 22 has a plurality of teeth portions 231 radially arranged around the center axis L with the front ends directed toward the center axis L, and an annular shape that connects the radially outer ends of the plurality of teeth portions 231 in the circumferential direction. A stator core 23 having a core back 232; and a coil 24 formed by winding a conductive wire 241 around each of the plurality of tooth portions 231. A small gap is formed between the outer peripheral surface 17a of the rotor magnet 17 and the radial direction. Are facing each other. The stator core 23 is formed of a thin metal plate, for example, a laminated steel plate in which a plurality of electromagnetic steel plates such as substantially circular silicon steel plates are laminated in the axial direction (in the present embodiment, the stator core 23 is formed by laminating two thin metal plates). is doing).

  In addition, on the inner periphery of the core back 232 between the two adjacent teeth portions 231 and 231, the connecting wire 242 of the conducting wire 241 is radially inward from the core back 232 so that the connecting wire 242 does not enter radially inward from the core back 232. A plurality of crossover locking protrusions 25 formed by bending the protruding protrusions upward are provided. The crossover wire 242 is wired so as to reach the other coil 24 from the one coil 24 via the radially outer side of the protruding portion 25.

  In FIG. 5, the coil 24 is wound around the three tooth portions 231 among the nine tooth portions 231, but actually, the coils 24 are similarly applied to the other tooth portions 231. Is wound.

  A flexible printed circuit board 26 (hereinafter referred to as FPC 26) is fixed so as to be disposed in contact with the upper side of the coil 24 or the core back 232. A conducting wire drawn from the coil 24 (hereinafter referred to as a drawing conducting wire) is led to the FPC 26 and joined to an electrode (land portion 264 described later) by solder or the like. When the stator 22 is energized from an external power source (not shown) via the FPC 26, a magnetic flux is generated in the stator 22, and a rotational torque is generated by a magnetic interaction between the magnetic field and the rotor magnet 17. Is driven to rotate.

  Hereinafter, the configuration of the FPC 26 will be described with reference to FIGS. 3, 6, and 7. 6 is a top view in which the disk 4 is omitted from FIG. 2, and FIG. 7 is a BB cross-sectional view in FIG.

  The FPC 26 has a main body portion 261, an electrical connection portion 262, and an external connection portion 263, and a land portion 264 made of copper foil or the like is formed on the surface. Specifically, the main body part 261 having a substantially arc shape that extends in the circumferential direction by connecting the radially outer ends of the plurality of electrical connection parts 262 and extends along the substantially annular core back 232 is formed by the coil 24 or It is fixed to the upper side of the core back 232. In the present embodiment, as shown in FIG. 7, the main body portion 261 is fixed to the upper surface 24 a of the coil 24. The electrical connection part 262 has a projecting part 262a extending on the outer side in the circumferential direction on both sides, and is disposed so as to be positioned between a plurality of adjacent tooth parts 231 and specifically between adjacent coils 24, A lead wire drawn from the coil 24 of the stator 22 is electrically connected. Since the spindle motor 1 according to the present embodiment is three-phase drive, four electrical connection portions 262 of U phase, V phase, W phase, and common are formed. The land portions 264 drawn from the respective electrical connection portions 262 are formed so as to be connected to the external connection portion 263 via the main body portion 261. The external connection portion 263 penetrates from the upper surface to the lower surface of the base 311 and is fixed to the lower surface of the base 311. An external power supply is supplied via the external connection portion 263, and the coil 24 is energized via the land portion 264 and the electrical connection portion 262.

<4. Configuration of shield member>
Next, the shield member 27 in this embodiment will be described with reference to FIGS. 3 and 7 to 10.

  The shield member 27 is an annular metal member formed from a soft magnetic material having a magnetic shield effect, and is disposed between the disk 4 and the coil 24 in the axial direction. The magnetic shielding effect is proportional to the magnetic permeability of the material, and the magnetic flux passing therethrough can be suppressed by absorbing the magnetic flux using a material having a high magnetic permeability. Therefore, by using a metal magnetic material, which is a soft magnetic material having a high permeability, for the shield member 27, a large amount of magnetic flux entering and exiting from the coil 24 during rotational driving is prevented from leaking above the shield member 27. Thus, it is possible to prevent the head portion 6 and the disk 4 from being reached. As a result, the magnetic flux generated from the coil 24 affects the disk 4 to prevent problems such as an error in reading the disk 4 and, in the worst case, information written on the disk 4 disappearing. In addition, the problem that the magnetic flux affects the head portion 6 to cause a magnetic action on the head portion 6 and the head portion 6 crashes can be prevented. As the material of the shield member 27, any magnetic material having a magnetic shielding effect may be used. For example, martensitic stainless steel, high permeability material permalloy (Ni alloy), cementene (Ni-Co alloy) may be used. Note that these permalloys and cementules are particularly effective for high frequency AC magnetic fields. In this embodiment, the magnetic flux that flows to the inner upper side of the magnetic flux generated in the coil 24 during driving is captured by the shield member 27, flows through the shield member 27, and returns to the coil 24 again. The shield member 27 is formed by a laminated magnetic shield plate in which one or a plurality of magnetic shield plates are laminated in the axial direction.

  The positional relationship in the axial direction between the shield member 27 and the coil 24 will be described with reference to FIG. The outer edge portion 27 a of the shield member 27 is fixed to the outer edge portion 311 c of the base 311, an adhesive or the like is applied to the lower surface of the shield member 27, and is directly bonded to the upper surface 24 a of the coil 24. It is also possible to dispose the shield member 27 above the coil 24 at a predetermined interval. Any positional relationship may be employed as long as the shield member 27 covers the upper side of the coil 24 to prevent leakage of magnetic flux from the coil 24.

<4-1. Shield member step>
Next, the shape of the shield member 27 according to the present embodiment will be described below. The shield member 27 according to the present embodiment includes a first flat surface portion 271 formed in a region corresponding to the swing operation region of the head portion 6, which includes a flat surface extending in a direction substantially perpendicular to the central axis L, and the first flat surface portion. 271 is arranged in the radial direction of the second flat surface portion 272 adjacent to the first flat surface portion 271 and positioned above the first flat surface portion 271, and the first flat surface portion 271 and the second flat surface portion 272, and is axially high in the circumferential direction. And a third flat surface portion 273 that is uniformly formed. Specifically, as shown in FIG. 7, the third plane part 273 is positioned below the second plane part 272 and is configured to have the same height as the first plane part 271.

  With this configuration, the inner peripheral surface 273a of the shield member 27 that faces the outer peripheral surface 17a of the rotor magnet 17 with a gap, that is, the inner peripheral surface 273a of the third flat portion 273 is uniform in the circumferential direction. Due to the configuration, the magnetic bias at the time of rotational driving of the motor 1 is stabilized, the rotation of the rotor unit 13 is stabilized, and the occurrence of problems such as PES, Puretone, RRO and the like can be suppressed.

  In addition, the step part of each boundary of the 1st plane part 271 of the shield member 27, the 2nd plane part 272, and the 3rd plane part 273 may be slope shape or a right angle shape.

<4-2. Relationship between shield member and FPC>
Next, the relationship between the shield member 27 and the FPC 26 will be described based on FIG. 3, FIG. 6, and FIG.

  First, as shown in FIG. 3, the electrical connection portion 262 of the FPC 26 is inclined downward from the radially inner end portion to the radially outer end portion of the electrical connection portion 262 with the radially outer end portion of the main body portion 261 as a fulcrum. A case where the configuration is bent in a shape will be described.

  In this case, as shown in FIG. 6, the circumferential width of the electrical connection portion 262 having the overhang portions 262 a on both sides is set between the adjacent tooth portions 231, specifically, the circumference of the gap between the adjacent coils 24. The electrical connection portion 262 that is configured to be equal to or smaller than the width in the direction and is bent in an inclined shape in cross-sectional view is positioned between the adjacent teeth portions 231, specifically between the adjacent coils 24. Are arranged to be. With this configuration, the overhanging portion 262a of the electrical connection portion 262 can be positioned on the side of the coil 24, and the lead wire drawn from the coil 24 is connected to the land portion 264 of the electrical connection portion 262. Good electrical connection can be achieved.

  In addition, since the second planar portion 272 of the shield member 27 is configured to be located above the first planar portion 271 and the third planar portion 273, the upper surface 24a of the coil 24 and the lower surface of the second planar portion 272 are configured. A space is formed between 272a and 272a. When an adhesive or the like is applied to the lower surface of the first flat portion 271 of the shield member 27 and adhered to the upper surface 24a of the coil 24, and the shield member 27 is fixed, this space has an FPC 26 as shown in FIG. The main body 261 is arranged. With this configuration, the spindle motor 1 can be thinned while the inner peripheral surface 273a of the shield member 27, that is, the inner peripheral surface 273a of the third flat surface portion 273, is configured to be uniform in the circumferential direction. it can. Note that not only the main body portion 261 of the FPC 26 but also a part of the electrical connection portion 262 can be arranged in the space.

  Further, the FPC 26 is fixed to the stator 22 by applying and bonding an adhesive or the like to the upper surface 24a of the coil 24 and the side surface of the electrical connection portion 262 of the FPC 26 to the side surface of the coil 24, respectively. Can be effectively retained.

  Further, by fixing the FPC 26, the fixed position can be maintained even by an external impact or the like, so that there is no risk that the conducting wire 241 forming the coil 24 is moved and cut.

  Next, as another embodiment, a case where the main body portion 261 and the electrical connection portion 262 of the FPC 26 are at the same height will be described below.

  In this case, since the main body portion 261 and the electrical connection portion 262 are on the same plane, the width in the circumferential direction of the electrical connection portion 262 having the protruding portions 262a on both sides is more specifically between adjacent tooth portions 231. It can also be configured to have a width wider than the circumferential width of the gap between adjacent coils 24. At this time, the electrical connection portion 262 and the overhang portion 262a can be in contact with the upper surface 24a of the coil 24, and the lead wire drawn out from the coil 24 can be electrically connected to the land portion 264 of the electrical connection portion 262. can do.

  Further, in this case, considering the reduction in thickness of the spindle motor 1, the main body 261 of the FPC 26 and the electric part are electrically connected to the space formed between the lower surface 272 a of the second flat portion 272 of the shield member 27 and the upper surface 24 a of the coil 24. It is desirable that the connection part 262 be arranged. In order to achieve this effect, the width obtained by combining the radial width of the main body portion 261 of the FPC 26 and the radial width of the electrical connection portion 262 is equal to the radial width of the second flat portion of the shield member 27. Or smaller than that.

  The shape of the first plane portion 271 has a substantially fan shape that radially expands from the radially inner side to the radially outer side. Further, the width in the circumferential direction of the first flat surface portion 271 is an area in which the head portion 6 can swing with a margin, and as shown in FIG. 10, the passage including the locus S in which the head portion 6 swings. The area is equivalent to the area or has a margin larger than the passing area.

<4-3. Insulating layer>
As shown in FIG. 9, the lower surface of the shield member 27 is covered with an insulating layer 28. Since the shield member 27 is conductive, by covering the shield member 27 with the insulating layer 28, the shield member 27 and the coil 24 can be electrically insulated and prevented from short-circuiting due to metal contact. . As a material of the insulating layer 28, for example, epoxy resin, polyimide resin, polyester resin, PES resin, acrylic resin, or the like can be used. As a method for forming the insulating layer 28, a sheet-like insulating film in which an adhesive such as PSA (Pressure Sensitive Adhesive) is applied to one surface is attached to the lower surface of the shield member 27. In this embodiment, the insulating film is attached to the shield member 27 with an adhesive such as PSA, but may be fixed with, for example, a double-sided tape. As another method, the insulating layer 28 can be covered by a method in which a molten resin agent is applied to the surface of the shield member 27 and cured. As a covering range of the insulating layer 28, it is only necessary to cover at least a portion of the lower surface of the shield member 27 facing the coil 24 in the axial direction. Of course, you may coat | cover to the range equivalent to the area of the lower surface of the shield member 27. FIG. In addition, although the 1st plane part 271 of the shield member 27, the 2nd plane part 272, and the 3rd plane part 273 each differ in axial direction height, as shown in FIG. 3, the insulation coat | covered on the lower surface of the shield member 27 The layer 28 is also coated in accordance with the respective axial heights, and the insulating layer 28 is coated on each of the first flat surface portion 271, the second flat surface portion 272, and the third flat surface portion 273.

<5. Other Examples>
In addition, about the structure of the shield member 27 which has several planes from which an axial direction height differs, in this embodiment, the shield member 27 comprised by laminating | stacking one or several sheets of magnetic shield plates to an axial direction is used for press etc. The first flat surface portion 271, the second flat surface portion 272, and the third flat surface portion 273 are formed by bending by plastic working, but the configuration of the shield member 27 is not limited to this. For example, the first flat surface portion 271, the second flat surface portion 272, and the third flat surface portion 273 may be separately formed and connected to form one shield member 27.

  As another embodiment, as shown in FIG. 11, the shield member 27 is configured such that the third plane portion 273 is located below the second plane portion 272 and is higher than the first plane portion 271. It is also possible to configure. As still another embodiment, as shown in FIG. 12, the third plane portion 273 is lower than the first plane portion 271, and the first plane portion 271 is lower than the second plane portion 272. It is also possible to do.

1 is a longitudinal sectional view of a disk drive device including a spindle motor according to an embodiment of the present invention. It is a top view for demonstrating the internal structure of a disk drive device. It is the sectional view on the AA line in FIG. It is a partial longitudinal cross-sectional view of the spindle motor for demonstrating a radial dynamic pressure bearing part and a thrust dynamic pressure bearing part. It is explanatory drawing of a stator. FIG. 3 is a top view with the disc removed from FIG. 2. It is BB sectional drawing in FIG. It is a figure which shows the shield member which concerns on one Embodiment of this invention. It is the figure which coat | covered the insulating layer on the lower surface of the shield member. FIG. 3 is an upper plan view for explaining the internal structure of the disk drive device including the shield member according to the embodiment of the present invention and excluding the disk. It is a figure which shows the shielding member which concerns on other embodiment. It is a figure which shows the shielding member which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spindle motor 2 Disk drive device 6 Head part 15 Rotor hub 17 Rotor magnet 17a Outer peripheral surface 22 Stator 231 Teeth part 232 Core back 24 Coil 24a Upper surface 241 Conductor 26 Flexible printed circuit board (FPC)
261 Main body part 262 Electrical connection part 262a Overhang part 263 External connection part 264 Land part 27 Shield member 271 First plane part 272 Second plane part 272a Lower surface 273 Third plane part 273a Inner peripheral surface 28 Insulating layer

Claims (7)

A spindle motor provided in a disk drive device including a head unit that reads and / or writes information from and to a disk by a swing operation, and a moving unit that moves the head unit along the plane of the disk. And
A rotor portion having a disc placement portion on which the disc is placed, and being rotatably supported by a bearing mechanism around a central axis;
A stator having coils formed by winding a plurality of teeth portions radially arranged around the central axis with leading ends thereof directed toward the central axis, and windings around the plurality of teeth portions;
An annular rotor magnet fixed to the rotor portion so as to face the tip portions of the plurality of teeth portions via a gap in the radial direction, and N poles and S poles are alternately magnetized in the circumferential direction;
A substantially annular shield member disposed between the disk and the coil in the axial direction;
With
The shield member is
A first plane portion corresponding to a swing operation region of the head portion, the plane portion extending in a direction substantially perpendicular to the central axis;
A second planar portion that is adjacent to the first planar portion in the circumferential direction and is located above the first planar portion with the direction along the central axis as the vertical direction;
A third plane part that is disposed radially inward of the second plane part and the first plane part, is located below the second plane part and has a uniform axial height in the circumferential direction;
A spindle motor comprising: The spindle motor according to claim 1,
The stator further includes a substantially annular core back that connects radially outer ends of the plurality of tooth portions in the circumferential direction,
A plurality of electrical connection portions disposed between the plurality of adjacent tooth portions, to which the conductive wires from the stator are electrically connected;
A substantially arc-shaped main body formed by extending the outer ends in the radial direction of the plurality of electrical connecting portions and extending in the circumferential direction;
A flexible printed circuit board having
At least a main body portion of the flexible printed circuit board is disposed between the lower surface of the second flat surface portion and the axial direction of the coil. The spindle motor according to claim 2, wherein
The width of the flexible printed circuit board combined with the radial width of the main body portion and the radial width of the electrical connection portion corresponds to or smaller than the radial width of the second planar portion of the shield member. A spindle motor characterized by that. The spindle motor according to any one of claims 1 to 3,
The spindle motor according to claim 1, wherein the first flat portion of the shield member has a substantially fan shape that radially expands from a radially inner side to a radially outer side. The spindle motor according to any one of claims 1 to 4,
The spindle motor according to claim 1, wherein the first plane part and the third plane part have the same axial height. The spindle motor according to any one of claims 1 to 5,
A spindle motor characterized in that an insulating layer is coated on a surface of the shield member on the coil side. A disk drive for rotating the disk,
A base member;
The spindle motor according to any one of claims 1 to 6, which is fixed inside the base member;
A head unit for reading and / or writing information to and from the disk;
And a moving means for moving the head portion along the plane of the disk.

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