JP2011142792A - Spindle motor and disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle motor, capable of suppressing a displacement to the magnet side of the edge of a magnetic member, and capable of avoiding even the increase of the number of parts, even when the magnetic member is thinned in the axial direction. <P>SOLUTION: The spindle motor 102 includes a soft magnetic member 134 and an insulating sheet 135. The soft magnetic member 134 is fixed onto a base member 131, and opposed to a magnet 143 through an opening in the axial direction. The insulating sheet 135 is arranged between the base member 131 and a coil 138, and electrically insulates the base member 131 and the coil 138. The insulating sheet 135 includes a cover 135b covering the top face of the edge in the radial direction of the soft magnetic member. Accordingly, the displacement to the magnet 143 side of the edge of the soft magnetic member 134 is suppressed. The displacement to the magnet 143 side of the edge of the soft magnetic member 134 is restrained by using the insulating sheet 135, thereby the increase of number of parts for the spindle motor 102 is avoided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  A hard disk device or an optical disk device is equipped with a spindle motor for rotating the disk around its central axis. The spindle motor has a stationary part fixed to the housing of the apparatus and a rotating part that rotates while supporting the disk. The spindle motor generates torque about the central axis by the magnetic flux generated between the stationary part and the rotating part, and rotates the rotating part with respect to the stationary part.

Some conventional spindle motors have a magnetic member for attracting the rotating part toward the stationary part. The magnetic member is fixed to the stationary part and generates an axial magnetic attractive force between the magnetic member and the magnet on the rotating part side. For example, Japanese Patent Laid-Open No. 2001-309605 describes a magnetic ring that is attached to a fixed member and applies a downward axial force to a rotor. Further, paragraph 0034 of Japanese Patent Laid-Open No. 2001-309605 describes that “the magnetic body ring 42 is fixed to the fixing member 21 with, for example, an adhesive”.
JP 2001-309605 A

  A magnetic attractive force always acts between the magnetic member and the magnet. For this reason, if the magnetic member is not sufficiently fixed to the stationary member, the magnetic member may be displaced toward the magnet. Generally, the magnetic member is fixed to the stationary member with sufficient fixing strength in order to prevent the magnetic member from being displaced toward the magnet.

  However, if the magnetic member is thinned in the axial direction in order to reduce the thickness of the spindle motor, partial bending of the magnetic member is likely to occur. In this case, if the adhesive is not sufficiently spread to the lower surface of the end edge portion of the magnetic member, the end edge portion of the magnetic member is likely to be displaced toward the magnet.

  On the other hand, if a unique component is provided in order to prevent displacement of the edge of the magnetic member toward the magnet, the number of components of the spindle motor increases. The increase in the number of parts becomes a factor that increases the cost of the spindle motor.

  An object of the present invention is to provide a spindle motor that can suppress the displacement of the edge portion of the magnetic member toward the magnet side even when the magnetic member is thinned in the axial direction, and can avoid an increase in the number of parts. .

  An exemplary first invention of the present application includes a stationary portion and a rotating portion that is rotatably supported with respect to the stationary portion, the rotating portion includes a magnet, and the stationary portion extends vertically. A base member having a substantially cup-shaped accommodation portion that extends in a direction orthogonal to the central axis and opens upward; a coil that is accommodated in the accommodation portion and faces the magnet in a radial direction through a gap; A sheet-like soft magnetic member housed in the housing portion and fixed to the base member and opposed to the magnet via a gap in the axial direction; and disposed between the base member and the coil; An insulating sheet that electrically insulates the member and the coil, and the insulating sheet is a spindle motor having a cover portion that covers an upper surface of a radial edge of the soft magnetic member.

  According to the exemplary first invention of the present application, the displacement of the edge portion of the soft magnetic member toward the magnet is suppressed by the cover portion of the insulating sheet. Further, since the insulating sheet is used to suppress the displacement of the edge portion of the soft magnetic member toward the magnet, an increase in the number of components of the spindle motor is avoided.

FIG. 1 is a partial longitudinal sectional view of a spindle motor. FIG. 2 is a longitudinal sectional view of the disk drive device. FIG. 3 is a longitudinal sectional view of the spindle motor. FIG. 4 is a partial longitudinal sectional view of the spindle motor. FIG. 5 is a partial longitudinal sectional view of a spindle motor according to a modification. FIG. 6 is a partial longitudinal sectional view of a spindle motor according to a modification. FIG. 7 is a partial longitudinal sectional view of a spindle motor according to a modification. FIG. 8 is a partial longitudinal sectional view of a spindle motor according to a modification. FIG. 9 is a partial top view of a thrust yoke according to a modification. FIG. 10 is a partial longitudinal sectional view of a thrust yoke according to a modification. FIG. 11 is a longitudinal sectional view of the vicinity of the elastic piece. FIG. 12 is a longitudinal sectional view of a spindle motor according to a modification. FIG. 13 is a partial longitudinal sectional view of a spindle motor according to a modification.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the following, the shape and positional relationship of each member will be described with the direction along the central axis as the vertical direction and the direction in which the substantially cup-shaped accommodation portion of the base member is open as the top. However, this is defined only in the vertical direction for convenience of explanation, and does not limit the posture of the spindle motor and the disk drive device according to the present invention in the usage state.

<1. Spindle motor according to one embodiment>
FIG. 1 is a partial longitudinal sectional view of a spindle motor 102 according to an embodiment of the present invention. As shown in FIG. 1, the spindle motor 102 includes a stationary part 103 and a rotating part 104. The rotating unit 104 is rotatably supported with respect to the stationary unit 103.

  The rotating unit 104 has a magnet 143. On the other hand, the stationary part 103 includes a base member 131, a coil 138, a soft magnetic member 134, and an insulating sheet 135.

  The base member 131 extends in a direction perpendicular to the central axis extending vertically. The base member 131 has a substantially cup-shaped accommodation part 131e that opens upward. The coil 138 is accommodated in the accommodating part 131e of the base member 131, and opposes the magnet 143 via a gap in the radial direction (a direction orthogonal to the central axis; the same applies hereinafter). The soft magnetic member 134 is a sheet-like member that is accommodated in the accommodating portion 131 e and fixed to the base member 131. The soft magnetic member 134 is opposed to the magnet 143 in the axial direction (direction along the central axis; hereinafter the same) via a gap. Further, the insulating sheet 135 is disposed between the base member 131 and the coil 138. The insulating sheet 135 electrically insulates the base member 131 and the coil 138.

  The insulating sheet 135 has a cover portion 135 b that covers the upper surface of the end edge portion in the radial direction of the soft magnetic member 134. The cover part 135b suppresses the displacement of the end edge part 134c of the soft magnetic member 134 toward the magnet 143 side. Further, since the insulating sheet 135 is used to suppress the displacement of the end edge portion 134c of the soft magnetic member 134 toward the magnet 143, an increase in the number of components of the spindle motor 102 is avoided.

<2. More specific embodiment>
<2-1. Configuration of disk drive>
Subsequently, a more specific embodiment of the present invention will be described.

  FIG. 2 is a longitudinal sectional view of the disk drive device 1. The disk drive device 1 is a device that reads and writes information from and to the disk 12 while rotating a magnetic disk 12 (hereinafter simply referred to as “disk 12”). As shown in FIG. 2, the disk drive device 1 includes a device housing 11, a disk 12, an access unit 13, and a spindle motor 2.

  The device housing 11 is a housing that accommodates the disk 12, the access unit 13, and the spindle motor 2. The upper portion of the device housing 11 is closed by a lid portion 11a. The access unit 13 reads and writes information from and to the disk 12 by moving the head 13 a along the recording surface of the disk 12 supported by the spindle motor 2. Note that the access unit 13 may perform only one of reading and writing of information with respect to the disk 12.

<2-2. Spindle motor configuration>
Next, the configuration of the spindle motor 2 will be described. FIG. 3 is a longitudinal sectional view of the spindle motor 2. As shown in FIG. 3, the spindle motor 2 includes a stationary portion 3 fixed to the device housing 11 of the disk drive device 1, and a rotating portion 4 that rotates around the central axis 9 while supporting the disk 12. ing.

  The stationary part 3 includes a base member 31, a stator unit 32, a circuit board 33, a thrust yoke 34, an insulating sheet 35, and a stationary bearing unit 36.

  The base member 31 is a part of the device housing 11 of the disk drive device 1 and is formed integrally with other parts of the device housing 11. The base member 31 has a cylindrical portion 31a, a bottom portion 31b, a wall portion 31c, and an outer flat plate portion 31d. The cylindrical part 31a is a part protruding upward from the inner edge part of the bottom part 31b. The bottom part 31b is a substantially disk-shaped part that extends radially outward from the lower end part of the cylindrical part 31a. The wall 31c is a part that spreads radially outward and obliquely upward from the outer edge of the bottom 31b. Further, the outer flat plate portion 31d is a portion that extends further radially outward from the outer edge portion of the wall portion 31c.

  The bottom 31b and the wall 31c of the base member 31 constitute a substantially cup-shaped accommodation part 31e that opens upward. A stator unit 32, a thrust yoke 34, an insulating sheet 35, and a rotor magnet 43, which will be described later, are housed inside the housing portion 31e. On the other hand, the circuit board 33 is arrange | positioned at the radial direction outer side of the accommodating part 31e. In the spindle motor 2, the stator unit 32 and the circuit board 33 do not overlap in the axial direction, and are disposed at substantially the same height. Thereby, the thickness of the whole spindle motor 2 in the axial direction is suppressed.

  The base member 31 may be a part of the device housing 11 as in the present embodiment, or may be a separate member fixed to the device housing 11.

  The stator unit 32 includes a stator core 37 and a plurality of coils 38. The stator unit 32 has a function of generating magnetic flux according to the drive current applied to the coil 38. The stator core 37 includes an annular core back 37a and a plurality of teeth portions 37b protruding from the core back 37a toward the radially outer side. The core back 37 a is fixed to the outer peripheral surface of the cylindrical portion 31 a of the base member 31. The stator core 37 is obtained, for example, by punching a plurality of electromagnetic steel sheets into the shape and laminating them in the axial direction.

  The coil 38 is configured by a conductive wire wound around each tooth portion 37 b of the stator core 37. The coil 38 is located above the bottom 31 b of the base member 31. The coil 38 of the present embodiment is composed of three conducting wires 38a for supplying three-phase AC currents. The end portions on the input side of the three conducting wires 38a are led out to the lower surface side of the bottom portion 31b through a through hole 31f formed in the bottom portion 31b.

  The circuit board 33 is a board on which an electronic circuit for supplying a drive current to the coil 38 is mounted. The circuit board 33 of the present embodiment is configured by a flexible printed board (FPC) that can be bent flexibly. The circuit board 33 is fixed to the outer surface of the wall portion 31c of the base member 31 and the lower surface of the outer flat plate portion 31d with an adhesive. A solder portion 33a is formed on the portion of the circuit board 33 fixed to the wall portion 31c. An end portion on the input side of a conducting wire 38a drawn from the coil 38 is connected to the solder portion 33a.

  The thrust yoke 34 is press-fitted inside the wall 31c of the base member 31, and is fixed to the upper surface of the bottom 31b with an adhesive. The upper surface of the thrust yoke 34 is opposed to the lower surface of a rotor magnet 43 described later with a gap in the axial direction. The thrust yoke 34 is a soft magnetic member formed of a magnetic material such as an electromagnetic steel plate (eg, silicon steel plate), a ferromagnetic stainless steel (eg, SUS430), or a cold rolled steel plate (eg, SPCC, SPCE). The thrust yoke 34 plays a role of attracting the rotating portion 4 to the stationary portion 3 side by a magnetic attractive force generated between the rotor magnet 43 and stabilizing the rotating posture of the rotating portion 4.

  The insulating sheet 35 is an insulating sheet disposed between the bottom 31 b of the base member 31 and the coil 38. For example, a polyethylene terephthalate (PET) film or the like is used for the insulating sheet 35. The insulating sheet 35 prevents electrical connection between the bottom 31 b of the base member 31 and the coil 38. By interposing the insulating sheet 35, the bottom 31b of the base member 31 and the coil 38 are accessible in the axial direction. Thereby, the axial thickness of the spindle motor 2 is further suppressed.

  The stationary bearing unit 36 is a mechanism for rotatably supporting the shaft 41 on the rotating unit 4 side. The stationary bearing unit 36 is fixed inside the cylindrical portion 31 a of the base member 31. The stationary bearing unit 36 includes a substantially cylindrical sleeve 36a and a cap 36b that closes an opening at a lower portion of the sleeve 36a. Lubricating oil is filled between the inner peripheral surface of the sleeve 36 a and the outer peripheral surface of the shaft 41.

  The rotating unit 4 includes a shaft 41, a hub 42, and a rotor magnet 43.

  The shaft 41 is a substantially cylindrical member that extends in the vertical direction along the central axis 9. The shaft 41 is inserted inside the sleeve 36 a and is rotatably supported with respect to the stationary bearing unit 36. The hub 42 is a member that is fixed to the shaft 41 and rotates together with the shaft 41. The hub 42 has a support surface that supports the disk 12.

  The rotor magnet 43 is fixed to the hub 42. The rotor magnet 43 has an annular shape centered on the central axis 9. The inner peripheral surface of the rotor magnet 43 is opposed to the teeth portion 37b and the coil 38 via a gap in the radial direction. The inner peripheral surface of the rotor magnet 43 is a magnetic pole surface in which N poles and S poles are alternately arranged.

  In such a spindle motor 2, when a drive current is applied to the coil 38 via the circuit board 33, radial magnetic flux is generated in the plurality of teeth portions 37 b of the stator core 37. Then, circumferential torque is generated by the action of magnetic flux between the teeth portion 37 b and the rotor magnet 43, and the rotating portion 4 rotates about the central axis 9 with respect to the stationary portion 3. The disk 12 supported by the hub 42 rotates around the central axis 9 together with the shaft 41 and the hub 42.

<2-3. Thrust yoke and insulation sheet>
Subsequently, a more detailed structure of the thrust yoke 34 and the insulating sheet 35 will be described. FIG. 4 is a partial longitudinal sectional view of the spindle motor 2 including the thrust yoke 34 and the insulating sheet 35.

  As shown in FIG. 4, the thrust yoke 34 has a flat plate portion 34a and a protruding portion 34b. The flat plate portion 34 a is an annular portion fixed to the upper surface of the bottom portion 31 b of the base member 31. The protruding portion 34b is a portion extending upward from the outer edge portion of the flat plate portion 34a. The thrust yoke 34 has high rigidity in the vicinity of the outer edge portion by having the protruding portion 34b.

  The flat plate portion 34a is formed in a substantially sheet shape that is thin in the axial direction. For this reason, in order to arrange the thrust yoke 34 in the accommodating portion 31e of the base member 31, a thin space may be ensured in the axial direction. Thereby, the axial thickness of the spindle motor 2 is further suppressed.

  The insulating sheet 35 includes a sheet main body portion 35a and a cover portion 35b. The sheet main body portion 35 a is an annular portion placed on the upper surface of the bottom portion 31 b of the base member 31. The sheet main body 35 a is located on the radially inner side of the thrust yoke 34 and is sandwiched between the bottom 31 b and the coil 38. The cover part 35 b is located on the radially outer side of the sheet main body part 35 a and is separated from the bottom part 31 b of the base member 31.

  The cover portion 35b extends from the outer edge portion of the seat main body portion 35a toward a position above the end edge portion 34c on the radially inner side of the thrust yoke 34. Accordingly, a part of the cover portion 35 b covers the upper surface of the end edge portion 34 c of the thrust yoke 34. In the present embodiment, the cover portion 35 b is in contact with the end edge portion 34 c of the thrust yoke 34. For this reason, the end edge portion 34 c is sandwiched between the bottom portion 31 b of the base member 31 and the cover portion 35 b of the insulating sheet 35.

  When the end edge portion 34c of the thrust yoke 34 is displaced upward due to the magnetic attractive force between the thrust yoke 34 and the rotor magnet 43, the end edge portion 34c receives a downward drag from the cover portion 35b. Thereby, the upward displacement of the end edge part 34c of the thrust yoke 34 is suppressed.

  In particular, the flat plate portion 34a of the thrust yoke 34 has a thin sheet shape in the axial direction. For this reason, partial deflection is likely to occur in the flat plate portion of the thrust yoke 34. Therefore, if there is no cover portion 35b and the adhesive is not sufficiently spread to the lower surface of the end edge portion 34c of the thrust yoke 34, the end edge portion 34c of the thrust yoke 34 is likely to be displaced upward. . In the present embodiment, the cover portion 35 b of the insulating sheet 35 suppresses upward displacement of the end edge portion 34 c of the thrust yoke 34. That is, the spindle motor 2 can suppress the upward displacement of the end edge portion 34c of the thrust yoke 34 while suppressing the axial thickness of the spindle motor 2 using the sheet-like thrust yoke 34. Yes.

  Further, in the structure of the present embodiment, it is not necessary to arrange a member for suppressing upward displacement of the thrust yoke 34 separately from the insulating sheet 35. Thereby, the increase in the number of parts of the spindle motor 2 is avoided. As a result, the axial thickness of the spindle motor 2 is further suppressed.

  The sheet main body portion 35 a of the insulating sheet 35 is sandwiched between the bottom portion 31 b of the base member 31 and the coil 38. That is, the lower surface of the sheet main body portion 35 a is in contact with the upper surface of the bottom portion 31 b of the base member 31, and the upper surface of the sheet main body portion 35 a is in contact with the coil 38. Thereby, the upward displacement of the insulating sheet 35 itself is suppressed. Accordingly, the upward displacement of the end edge portion 34c of the thrust yoke 34 is further suppressed. Further, the bottom 31b of the base member 31, the insulating sheet 35, and the coil 38 are densely arranged in the axial direction. Thereby, the axial thickness of the spindle motor 2 is further suppressed.

  A through hole 31 f extending in the axial direction is formed in the bottom 31 b of the base member 31. The through hole 31 f is located below the coil 38. The insulating sheet 35 is formed with an opening 35c communicating with the through hole 31f. The insulating sheet 35 has a cylindrical sheet tube portion 35d extending downward from a position around the opening portion 35c. The sheet cylinder portion 35 d is fitted in the through hole 31 f of the base member 31.

  The through hole 31 f is sealed with an adhesive 39. Thereby, the internal space and the external space of the apparatus housing 11 are separated. Further, the adhesive 39 fixes the sheet cylinder portion 35 d of the insulating sheet 35 to the base member 31. Since the insulating sheet 35 is fixed to the base member 31, the upward displacement of the insulating sheet 35 itself is suppressed. For this reason, the upward displacement of the end edge portion 34c of the thrust yoke 34 is further suppressed.

  The insulating sheet 35 is fixed to the base member 31 with an adhesive 39 held in the through hole 31f. In the present embodiment, the adhesive 39 is not interposed between the upper surface of the bottom 31 b of the base member 31 and the lower surface of the sheet main body 35 a of the insulating sheet 35. Thereby, the axial thickness of the spindle motor 2 is further suppressed.

  The entire insulating sheet 35 is arranged radially inward from the inner peripheral surface of the rotor magnet 43. That is, the insulating sheet 35 is disposed at a position that does not overlap the rotor magnet 43 in the axial direction. For this reason, even if the cover part 35b of the insulating sheet 35 is bent upward, the insulating sheet 35 and the rotor magnet 43 do not contact each other. In addition, since the insulating sheet 35 and the rotor magnet 43 do not come into contact with each other, it is not necessary to ensure an axial interval between the insulating sheet 35 and the rotor magnet 43. Therefore, the axial thickness of the spindle motor 2 can be further suppressed.

<3. Modification>
Subsequently, a modification will be described. In the following modification, the basic configuration is the same as the configuration in FIGS. 3 and 4. In the following, portions different from those in FIGS. 3 and 4 will be mainly described.

  For example, as shown in FIG. 5, the cover portion 235 b of the insulating sheet 235 may be in surface contact with the upper surface of the end edge portion 234 c of the thrust yoke 234. In the example of FIG. 5, since the cover portion 235b is lying on the upper surface of the thrust yoke 234, the dimension in the axial direction of the insulating sheet 235 is further suppressed.

  Further, as shown in FIG. 6, the cover portion 335 b of the insulating sheet 335 may be provided above the end edge portion 334 c of the thrust yoke 334 via a gap. In the example of FIG. 6, when the upward displacement of the end edge portion 334c of the thrust yoke 334 occurs, the end edge portion 334c abuts on the cover portion 335b and receives a downward drag from the cover portion 335b. Therefore, the displacement of the end edge part 334c upward is suppressed.

  However, in order to further suppress the axial dimension of the insulating sheet 335, it is preferable that the cover portion 335b of the insulating sheet 335 is in contact with the end edge portion 334c of the thrust yoke 334.

  Further, as shown in FIG. 7, the coil 438 may be provided above the sheet main body portion 435a via a gap. In the example of FIG. 7, the insulating sheet 435 is fixed to the base member 431 with an adhesive 439. Thereby, the overall upward displacement of the insulating sheet 435 is prevented. Even if a partial upward displacement occurs in the insulating sheet 435, the displacement stops when the insulating sheet 435 contacts the lower surface of the coil 438. That is, the amount of upward displacement of the insulating sheet 435 is limited by the coil 438. Therefore, upward displacement of the end edge portion 434c of the thrust yoke 434 is also limited.

  Further, as shown in FIG. 8, the radially inner end edge portion 534 c of the thrust yoke 534 may extend to a position below the coil 538 and the insulating sheet 535. In the example of FIG. 8, the end portion 534 c on the radially inner side of the thrust yoke 534 is sandwiched between the coil 538 and the insulating sheet 535 and the bottom portion 531 b of the base member 531. For this reason, the upward displacement of the end edge portion 534c of the thrust yoke 534 relative to the bottom portion 531b of the base member 531 is more reliably suppressed.

  In the example of FIG. 8, the thrust yoke 534 and the insulating sheet 535 or the insulating sheet 535 and the coil 538 may be separated from each other.

  Further, the thrust yoke 34 may have a structure for further improving the fixing strength with the base member 31. FIG. 9 is a partial top view of a thrust yoke 634 according to a modification. FIG. 10 is a partial longitudinal sectional view of the thrust yoke 634 viewed from the position XX in FIG. The thrust yoke 634 shown in FIGS. 9 and 10 has a fixing portion 634d. The fixing portion 634d includes a pair of notches 634e formed in the protruding portion 634b, and an elastic piece 634f formed between the pair of notches 634e. The elastic piece 634f extends radially outward from the outer edge portion of the flat plate portion 634a and is curved upward. The radially outer end portion of the elastic piece 634f is located on the radially outer side than the outer edge portion of the protruding portion 634b. The elastic piece 634f can be bent according to the stress received from the radially outer end. That is, the elastic piece 634f has flexibility.

  FIG. 11 is a longitudinal sectional view of the vicinity of the elastic piece 634f when the thrust yoke 634 of FIGS. 9 and 10 is fixed to the base member 31. FIG. The wall portion 31 c of the base member 31 has a cylindrical surface 31 g that faces the outer peripheral surface of the thrust yoke 634. The elastic piece 634f contacts the cylindrical surface 31g of the wall portion 31c and bends inward in the radial direction. Therefore, the thrust yoke 634 is firmly fixed to the base member 31 by the radial drag between the elastic piece 634f and the cylindrical surface 31g.

  In particular, the elastic piece 634 f causes the corner portion 634 g between the upper surface and the outer peripheral surface thereof to abut on the cylindrical surface 31 g of the base member 31. And the corner | angular part 634g presses the cylindrical surface 31g with the elastic force of the elastic piece 634f. For this reason, when the thrust yoke 634 receives an upward force, the corner portion 634g abuts on the cylindrical surface 31g with an elastic force, so that the upward movement of the thrust yoke 634 is suppressed.

  When the thrust yoke 34 is fixed to the base member 31, the elastic piece 634 f bends according to the dimension of the cylindrical surface 31 g of the base member 31. For this reason, the required dimensional accuracy of the cylindrical surface 31g of the base member 31 can be reduced as compared with the case where the thrust yoke 34 without the elastic piece 634f is press-fitted into the base member 31.

  In the example of FIGS. 9 and 10, the upper end portion of the elastic piece 634f is located below the upper end portion of the protruding portion 634b. In this way, when the thrust yoke 634 is attached to the base member 31, it is easy to press the upper end portion of the protruding portion 634b without pressing the elastic piece 634f. Therefore, the thrust yoke 634 can be attached to the base member 31 without applying an excessive external force downward to the elastic piece 634f.

  In the example of FIGS. 9 and 10, an elastic piece 634f is formed between the pair of notches 634e. Thereby, the length of the elastic piece 634f in the radial direction is secured without causing the elastic piece 634f to protrude excessively radially outward, and flexibility is imparted to the elastic piece 634f. Further, it is possible to bend only the elastic piece 634f while preventing distortion of other portions in the thrust yoke 634.

  In the example of FIGS. 9 and 10, the radially inner end of the notch 634e is located radially inward from the outer edge of the flat plate 634a. In this way, the fixed state of the flat plate portion 634a with respect to the bottom portion 31b of the base member 31 can be confirmed. For example, the presence or absence of a gap between the bottom portion 31b and the flat plate portion 634a and the application state of the adhesive between the bottom portion 31b and the flat plate portion 634a can be confirmed.

  It is preferable that the elastic piece 634f is arranged on the outer side in the radial direction than the rotor magnet 43. In this way, the upper surface of the flat plate portion 634a located radially inward from the notch 634e of the thrust yoke 634 faces the lower surface of the rotor magnet 43 in the axial direction. Therefore, the directivity in the axial direction of the magnetic attractive force generated between the rotor magnet 43 and the thrust yoke 634 is increased.

  Note that the fixing portion 634d may be provided at only one location of the thrust yoke 634, or may be provided at a plurality of locations. However, the positional accuracy of the thrust yoke 634 with respect to the central axis 9 can be further improved by having two or more, preferably three or more fixing portions 634d.

  Further, as shown in FIG. 12, the spindle motor 702 may have a rotor magnet 43 on the radially inner side of the stator unit 32. 13 is a partial longitudinal sectional view of the spindle motor 702 of FIG. In FIGS. 12 and 13, the same reference numerals as those in FIGS. 3 and 4 are attached to portions corresponding to the respective portions of the spindle motor 2 of the above embodiment.

  Also in the spindle motor 702, the thrust yoke 34 is disposed below the rotor magnet 43. An insulating sheet 35 is disposed between the bottom 31 b of the base member 31 and the coil 38. The insulating sheet 35 has a cover portion 35 b that covers the radial yoke outer edge 34 c above the thrust yoke 34. For this reason, the upward displacement of the end edge part 34c of the thrust yoke 34 is suppressed by the cover part 35b. Further, since the insulating sheet 35 is used to suppress the upward displacement of the end edge portion 34c of the thrust yoke 34, an increase in the number of parts of the spindle motor 2 is avoided.

  Further, the present invention is not limited to the above-described exemplary embodiments and modifications, and various modifications can be made.

  The cover portion 35b of the insulating sheet 35 may cover the end edge portion 34c of the thrust yoke 34 over the entire circumference or may partially cover it. That is, the cover part 35 b of the insulating sheet 35 only needs to cover at least a part of the end edge part 34 c of the thrust yoke 34.

  Further, the thrust yoke 34 may be annular as in the above-described embodiment. As another example, the thrust yoke 34 may have a C shape, that is, an arc shape in which both ends in the circumferential direction face each other. .

  The present invention may also be applied to a disk other than a magnetic disk, for example, a spindle motor that rotates an optical disk, and a disk drive device that includes the spindle motor.

  The present invention can be used for a spindle motor and a disk drive device.

DESCRIPTION OF SYMBOLS 1 Disk drive device 2,102,702 Spindle motor 3,103 Stationary part 4,104 Rotation part 9 Center shaft 11 Apparatus housing 12 Disk 13 Access part 31,131,431,531 Base member 31b, 531b Bottom part 31c Wall part 31e, 131e Housing portion 31f Through hole 31g Cylindrical surface 32 Stator unit 33 Circuit board 34, 234, 334, 434, 534, 634 Thrust yoke 34a, 634a Flat plate portion 34b, 634b Protruding portion 34c, 134c, 234c, 334c, 434c, 534c End Edge portion 35, 135, 235, 335, 435, 535 Insulating sheet 35a, 435a Sheet body portion 35b, 135b, 235b, 335b, 435b, 535b Cover portion 35c Opening portion 35d Seat tube portion 36 Stationary bearing Knit 37 stator core 38,138,438,538 coil 39,439 adhesive 41 shaft 42 hub 43 rotor magnet 134 magnetically soft members 143 magnet 634d fixing portion 634e notch 634f elastic piece 634g corner

Claims (12)

A stationary part;
A rotating part that is rotatably supported with respect to the stationary part,
The rotating part has a magnet,
The stationary part is
A base member having a substantially cup-shaped accommodation portion that extends in a direction perpendicular to the central axis extending vertically and opens upward;
A coil housed in the housing portion and opposed to the magnet in a radial direction through a gap;
A sheet-like soft magnetic member housed in the housing portion and fixed to the base member and opposed to the magnet via a gap in the axial direction;
An insulating sheet that is disposed between the base member and the coil and electrically insulates the base member and the coil;
Have
The said insulating sheet is a spindle motor which has a cover part which covers the upper surface of the edge part of the radial direction of the said soft magnetic member. The spindle motor according to claim 1,
A spindle motor in which the cover portion of the insulating sheet is in contact with the edge portion of the soft magnetic member. The spindle motor according to claim 1 or 2,
A spindle motor in which the lower surface of the insulating sheet is in contact with the upper surface of the base member, and the coil is in contact with the upper surface of the insulating sheet. The spindle motor according to claim 1 or 2,
The spindle motor, wherein the edge portion of the soft magnetic member is positioned below the coil and the insulating sheet. In the spindle motor according to any one of claims 1 to 4,
A spindle motor in which the insulating sheet is fixed to the base member with an adhesive. The spindle motor according to claim 5, wherein
The base member has a through hole formed in the axial direction below the coil,
The insulating sheet has a sheet tube portion disposed in the through hole,
The adhesive is a spindle motor that seals the through hole and fixes the sheet tube portion to the base member. In the spindle motor according to any one of claims 1 to 6,
A spindle motor in which the insulating sheet and the magnet do not overlap in the axial direction. In the spindle motor according to any one of claims 1 to 7,
The magnet is located radially outside the coil;
The base member has a cylindrical surface facing the outer peripheral surface of the soft magnetic member,
The soft magnetic member is
An annular flat plate portion;
A projecting portion extending upward from an outer edge portion of the flat plate portion;
A pair of notches provided in the protruding portion;
An elastic piece having flexibility, disposed between the pair of notches,
Have
A spindle motor in which the elastic piece is in contact with the cylindrical surface of the base member. The spindle motor according to claim 8, wherein
The elastic piece is curved upward from the outer edge portion of the flat plate portion,
A spindle motor in which a corner located between an upper surface and an outer peripheral surface of the elastic piece is in contact with the cylindrical surface of the base member. In the spindle motor according to claim 8 or 9,
A spindle motor in which an upper end portion of the elastic piece is positioned below an upper end portion of the protruding portion. In the spindle motor according to any one of claims 8 to 10,
A spindle motor in which a radially inner end portion of the notch portion is located radially inward from an outer edge portion of the flat plate portion. A spindle motor according to any one of claims 1 to 11,
An access unit that performs at least one of reading and writing of information with respect to the disk held by the rotating unit of the spindle motor;
A housing for housing the spindle motor and the access unit;
A disk drive device comprising:

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