JP2010170631A - Chucking device, brushless motor and disk drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve rotation accuracy by maintaining perpendicularity between a shaft axis and an upper surface of a magnetic material with high accuracy. <P>SOLUTION: A chucking device includes: a disk mounting unit 42 having a mounting face fixed to a shaft 41 to mount a circular plate-shaped disk having a circular hole at the center; a disk inner peripheral edge support unit 43 having a support face on the upper side of the disk mounting unit to support an inner peripheral edge of the disk; and a magnetic material 44 fixed to the shaft 41. The magnetic material includes: a disk portion 441 having a circular hole at the center; and a cylinder portion 442 extending downward from the inner peripheral edge of the disk portion 441 and being fixed to the shaft 41. The thickness of the cylinder portion 442 in the radial direction is smaller than the thickness of the disk portion 441 in the axial direction. A load applied to the shaft 41 and the magnetic material 44 is reduced when the shaft 41 and the magnetic material 44 are fixed, thereby maintaining the perpendicularity between the axis 9 of the shaft 41 and the upper surface of the magnetic material 44 with high accuracy when fixed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chucking device, a brushless motor, and a disk drive device.

  A disk drive device such as an optical disk device is equipped with a brushless motor for rotating the disk. The brushless motor has a chucking device that rotates together with the rotating unit. The disk drive device rotates the disk by driving a brushless motor while holding the disk between the chucking device and a clamper provided thereabove.

Some of such chucking devices include a movement restricting portion fixed to a shaft and a clamp magnet. The clamp magnet, for example, generates a magnetic attraction force with the clamper and plays a role of attracting the clamper to the chucking device side. Japanese Patent Laying-Open No. 2008-210421 discloses an example of a conventional chucking device having a movement restricting unit.
JP 2008-210421 A

  In the chucking device, the movement restricting portion is fixed to the shaft by press fitting or the like. However, when the shaft and the movement restricting portion are fixed by press fitting or the like, a large load is applied to both the shaft and the movement restricting portion. At this time, the perpendicularity between the axis of the shaft and the surface (upper surface) of the movement restricting portion sometimes deteriorated.

  The object of the present invention is to reduce the load applied to the shaft and the movement restricting portion when the shaft and the movement restricting portion are fixed, and to maintain the perpendicularity between the axis of the shaft and the surface of the movement restricting portion at the time of fixing. It is to provide a chucking device. Furthermore, it is providing the brushless motor and disk drive device which comprise it.

  In order to solve the above-mentioned problems, a first invention of the present application is a mounting on which a shaft arranged in a vertical direction along a central axis, and a disk-shaped disc fixed to the shaft and having a circular hole in the center. A disk mounting portion having a mounting surface; a disk inner edge support portion having a support surface for supporting an inner edge portion of the disk on the upper side of the disk mounting portion; and a magnetic member fixed to the shaft, The magnetic member has a disc portion having a circular hole in the center, and a cylindrical portion that extends downward from an inner edge portion of the disc portion and is fixed to the shaft, and the radial thickness of the cylindrical portion is The chucking device is thinner than the thickness of the disk portion in the axial direction.

  According to a second aspect of the present invention, a stationary part, a rotating part supported to be rotatable about the central axis with respect to the stationary part, and the central axis between the stationary part and the rotating part. A brushless motor comprising: a torque generator that generates torque to be generated; and a chucking device of the first invention that rotates together with the rotating unit.

  The third invention of the present application is directed to the brushless motor of the second invention, a clamper that presses the disk to the mounting surface side by the attractive force between the magnetic member, and the disk held by the chucking device. And a recording / reproducing unit that performs at least one of reading and writing of information.

  According to the first invention of the present application, the cylindrical portion of the magnetic member is fixed to the shaft. Since the radial thickness of the cylindrical portion is thinner than the axial thickness of the disc portion, the cylindrical portion can be easily fixed to the shaft, and the load applied to the magnetic member and the shaft during fixing can be reduced. Thereby, the perpendicularity between the axis of the shaft and the upper surface of the magnetic member can be maintained with high accuracy.

  According to the second invention of the present application, the rotational accuracy of the disk can be improved by maintaining the perpendicularity between the axis of the shaft and the upper surface of the magnetic member with high accuracy.

  According to the third invention of the present application, by maintaining the perpendicularity between the axis of the shaft and the upper surface of the magnetic member, it is possible to improve the rotation accuracy of the disk and reduce errors in reading and writing information in the recording / reproducing unit. it can.

FIG. 1 is a diagram conceptually illustrating a chucking device. FIG. 2 is a longitudinal sectional view of the disk drive device. FIG. 3 is a longitudinal sectional view of the brushless motor. FIG. 4 is a longitudinal sectional view of the chucking device and the clamper in a state where the disc is held. FIG. 5 is a longitudinal sectional view of the yoke. FIG. 6 is a photograph of the yoke. FIG. 7 is a flowchart showing the manufacturing procedure of the yoke. FIG. 8 is a longitudinal sectional view showing a state during the manufacturing of the yoke. FIG. 9 is a longitudinal sectional view showing a state in the middle of manufacturing of the yoke. FIG. 10 is a longitudinal sectional view showing a state in the middle of manufacturing the yoke. FIG. 11 is a longitudinal sectional view showing a state in the middle of manufacturing the yoke. FIG. 12 is a top view of the yoke. FIG. 13 is a top view of the yoke.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, for example, in FIG. 1, the direction along the central axis 9 is the up-down direction, and the disc inner edge support portion 43 side (cone 43 side with respect to the turntable 42) is up with respect to the disc placement portion 42. The shape and positional relationship of each member will be described. However, this is defined only in the vertical direction for convenience of explanation, and the installation posture when the chucking device, the brushless motor, and the disk drive device of the present invention are mounted on an actual device is limited. Not what you want.

<1. Chucking Device According to One Embodiment>
FIG. 1 is a diagram conceptually showing a chucking device 4 according to an embodiment of the present invention. The chucking device 4 is a device for holding a disk-shaped disc 90 having a circular hole in the center. As shown in FIG. 1, the chucking device 4 includes a shaft 41 disposed in the vertical direction along the central axis 9, a disk mounting portion 42 having a mounting surface 42 b on which the disk 90 is mounted, A disk inner edge support portion 43 having a support surface 43 a for supporting the inner edge portion of the disk 90 and a magnetic member 44 are provided on the upper side of the mounting portion 42. The disk mounting portion 42 and the magnetic member 44 are fixed to the shaft 41.

  The magnetic member 44 includes a disc portion 441 having a circular hole in the center, and a cylindrical portion 442 that extends downward from the inner edge portion of the disc portion 441 and is fixed to the shaft 41. The thickness d1 in the radial direction of the cylindrical portion 442 of the magnetic member 44 is smaller than the thickness d2 in the axial direction of the disc portion 441. For this reason, the cylindrical portion 442 can be easily fixed to the shaft 41. Therefore, when the shaft 41 and the magnetic member 44 are fixed, the load applied to the shaft 41 and the magnetic member 44 is reduced, and the perpendicularity between the axis of the shaft 41 and the upper surface of the disk portion 441 of the magnetic member 44 is fixed at the time of fixing. High accuracy can be maintained.

<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 or writes information while rotating an optical disk 90 (hereinafter simply referred to as “disk 90”) about a central axis 9. As shown in FIG. 2, the disk drive device 1 mainly includes a device housing 11, a tray 12, a brushless motor 13, a clamper 14, and a recording / reproducing unit 15.

  The apparatus housing 11 is a housing that accommodates the tray 12, the brushless motor 13, the clamper 14, and the recording / reproducing unit 15. The tray 12 is a mechanism for transporting the disk 90 between the outside of the apparatus housing 11 and the brushless motor 13. The brushless motor 13 is fixed to a chassis 16 provided inside the apparatus housing 11. Further, the brushless motor 13 has a chucking device 4 that holds the disk 90 on the upper portion thereof. The disk 90 moved from the tray 12 to the chucking device 4 is held between the chucking device 4 and the clamper 14 and rotated about the central axis 9 by the brushless motor 13. The recording / reproducing unit 15 reads or writes information by moving the optical pickup unit 151 along the recording surface of the disk 90 rotated by the brushless motor 13.

  The optical pickup unit 151 of the recording / reproducing unit 15 may perform both reading and writing of information.

<2-2. Configuration of brushless motor>
Next, the configuration of the brushless motor 13 will be described. FIG. 3 is a longitudinal sectional view of the brushless motor 13. As shown in FIG. 3, the brushless motor 13 includes a stationary part 2, a rotating part 3, and a chucking device 4. The stationary part 2 is fixed to the chassis 16 of the disk drive device 1. The rotating part 3 is supported so as to be rotatable with respect to the stationary part 2. The chucking device 4 rotates together with the rotating unit 3 while holding the disk 90 on the upper side of the rotating unit 3.

  The stationary part 2 mainly includes a base member 21, a stationary bearing unit 22 fixed to the base member 21, and a magnetic flux generating part 23. The stationary bearing unit 22 is a mechanism that supports the shaft 41 in a rotatable state. The magnetic flux generation unit 23 includes a stator core 231 having a plurality of tooth portions 23a, and a coil 232 wound around each tooth portion 23a.

  The rotating unit 3 mainly includes a shaft 41, a rotor holder 31, and a rotor magnet 32. The shaft 41 is a substantially cylindrical member disposed in the vertical direction along the central axis 9. The rotor holder 31 is a member that is fixed to the shaft 41 and rotates together with the shaft 41. The rotor magnet 32 is fixed to the rotor holder 31. The rotor magnet 32 has an annular shape, and the inner peripheral surface thereof is a magnetic pole surface facing the end surface of the tooth portion 23a of the stator core 231.

  When a drive current is applied to the coil 232 of the stationary part 2, radial magnetic flux is generated in the plurality of tooth parts 23 a of the stator core 231. A circumferential torque is generated by the action of the magnetic flux between the tooth portion 23 a and the rotor magnet 32, and the rotating portion 3 rotates about the central axis 9 with respect to the stationary portion 2.

  The chucking device 4 has a common shaft 41 with the rotating unit 3. The chucking device 4 includes a turntable 42, a cone 43, a yoke 44, and a coil spring 45.

  The turntable 42 is a member on which the disk 90 is placed. The turntable 42 includes a disk portion 421 that is fixed to the shaft 41 on the upper side of the rotor holder 31, and a base portion 422 that is positioned on the radially outer side of the disk portion 421. The upper surface 42 a of the base part 422 is formed at a position higher than the upper surface of the disk part 421. The turntable 42 is a resin member obtained by injection molding, for example.

  An annular rubber member 423 is fixed to the upper surface 42 a of the base portion 422 of the turntable 42. The disk 90 is placed on the turntable 42 with its lower surface in contact with the upper surface 42 b of the rubber member 423. That is, in this embodiment, the turntable 42 and the rubber member 423 integrally form a disk mounting portion, and the upper surface 42b of the rubber member 423 is a disk mounting surface.

  The cone 43 is a member for supporting the edge of a circular hole formed at the center of the disk 90, that is, the inner edge of the disk 90. The cone 43 is attached on the upper side of the disc portion 421 of the turntable 42 so as to be slidable in the axial direction with respect to the shaft 41. The cone 43 is a resin member obtained by injection molding, for example.

  The cone 43 includes an annular sliding portion 431 having an inner peripheral surface opposed to the outer peripheral surface of the shaft 41 via a minute gap (for example, about several tens of μm), and a circle extending radially outward from the sliding portion 431. It has a plate part 432, a cylindrical part 433 extending upward from the outer edge part of the disk part 432, and a claw part 434 that extends radially outward and downward from the upper end part of the cylindrical part 433. The outer peripheral surface of the claw portion 434 of the cone 43 is a support surface 43 a that supports the inner edge portion of the disk 90. In addition, a plurality of ribs 435 are formed between the cylindrical portion 433 and the claw portion 434 of the cone 43 so as to come into contact with the upper end portion of the coil spring 45.

  The yoke 44 is a magnetic member made of a magnetic material. The yoke 44 is fixed to the shaft 41 on the upper side of the sliding portion 431 of the cone 43. The yoke 44 includes a disc portion 441 having a circular hole in the center, and a cylindrical portion 442 extending downward from the inner edge portion of the disc portion 441. The yoke 44 generates a magnetic attraction force between the yoke 44 and a clamp magnet 144 (see FIG. 4) provided on the clamper 14, thereby attracting the clamper 14 toward the turntable 42.

  The detailed shape and the like of the yoke 44 will be described later.

  The coil spring 45 is an elastic member for biasing the cone 43 toward the yoke 44 side. The coil spring 45 is inserted between the turntable 42 and the cone 43 in a state in which the coil spring 45 expands and contracts in the axial direction and is compressed more than the natural length. For this reason, the coil spring 45 applies an upward biasing force to the cone 43. When the chucking device 4 does not hold the disc 90, the cone 43 is pressed against the yoke 44 by the biasing force of the coil spring 45 as shown in FIG. 2, and the upper surface of the sliding portion 431 of the cone 43 and the yoke 44 are pressed. It will be in the state which the lower surface of the cylindrical part 442 contact | abutted.

  FIG. 4 is a longitudinal sectional view of the chucking device 4 and the clamper 14 in a state where the disk 90 is held. As shown in FIG. 4, the clamper 14 includes a substantially disc-shaped lid portion 141, a convex portion 142 projecting downward from the center of the lid portion 141, and a radially outer side from the outer edge portion of the lid portion 141. And a sleeve portion 143 extending downward. A clamp magnet 144 is fixed to the lid 141 at a position substantially above the yoke 44.

  When the disk 90 is held, the clamper 14 is attracted to the yoke 44 side by a magnetic attractive force generated between the clamp magnet 144 and the yoke 44. The lower surface of the sleeve portion 143 of the clamper 14 comes into contact with the upper surface of the disc 90, and the disc 90 is sandwiched between the lower surface of the sleeve portion 143 and the upper surface 42b of the rubber member 423. At this time, the support surface 43 a of the cone 43 abuts against the inner edge of the disk 90 at a location corresponding to the diameter of the circular hole of the disk 90. The cone 43 is pressed against the inner edge of the disk 90 and descends against the urging force of the coil spring 45.

  The support surface 43 a of the cone 43 abuts against the inner edge of the disk 90, thereby restricting the radial position of the disk 90 so that the center of the disk 90 is positioned on the central axis 9. Further, the upper surface 42a of the rubber member 423 and the lower surface of the sleeve portion 143 of the clamper 14 are in contact with the lower surface and the upper surface of the disk 90, respectively, thereby restricting the axial position and posture of the disk 90.

<2-3. Detailed shape of yoke>
Next, a more detailed shape of the yoke 44 will be described. FIG. 5 is a longitudinal sectional view of the yoke 44.

  As described above, the yoke 44 includes the disc portion 441 having a circular hole in the center, and the cylindrical portion 442 extending downward from the inner edge portion of the disc portion 441. The yoke 44 is fixed to the shaft 41 by press-fitting the upper end portion of the shaft 41 into the cylindrical portion 442. The yoke 44 of the present embodiment is a press-formed product obtained by press-forming a metal plate. For this reason, the yoke 44 of the present embodiment can be obtained at a lower cost than that obtained by other processing methods (for example, sintering).

(A) About the thickness of a disc part and a cylindrical part As shown in FIG. 5, the thickness d1 of the radial direction of the cylindrical part 442 of the yoke 44 is thinner than the thickness d2 of the axial direction of the disc part 441. For this reason, the cylindrical part 442 can be easily molded by press molding. Further, the cylindrical portion 442 can be formed with high dimensional accuracy by making the radial thickness d1 relatively thin.

  Further, the yoke 44 of the present embodiment is easy to press fit into the shaft 41 because the radial thickness d1 of the cylindrical portion 442 is thinner than the axial thickness d2 of the disc portion 441. Yes. That is, the shaft 41 and the yoke 44 can be fixed by press fitting without applying a large load to both the shaft 41 and the yoke 44. Therefore, deformation of the shaft 41 or the yoke 44 can be suppressed during press-fitting, and the perpendicularity between the axis of the shaft 41 and the upper surface of the disk portion 441 of the yoke 44 can be maintained with high accuracy. Here, the squareness means a small deviation of a linear feature that should be perpendicular to a datum straight line or a geometric straight line perpendicular to the datum plane. Further, by maintaining the perpendicularity between the axis of the shaft 41 and the upper surface of the disk portion 441 with high accuracy, the rotation accuracy of the disk 90 by the brushless motor 13 is improved, and errors in reading and writing information in the recording / reproducing unit 15 Can be reduced.

  Further, the yoke 44 of the present embodiment generates a high magnetic attraction force between the yoke portion 44 and the clamper 14 because the axial thickness d2 of the disc portion 441 is larger than the radial thickness d1 of the cylindrical portion 442. be able to. For this reason, in this embodiment, the disk 90 can be firmly held between the chucking device 4 and the clamper 14.

(B) About the shape of the outer peripheral surface of a disc part The outer peripheral surface of the disc part 441 of the yoke 44 has an upper cut surface 44a formed from the upper end to a predetermined height position, and the predetermined height. And a lower cut surface 44b formed from the position to the lower end. The upper cut surface 44a and the lower cut surface 44b are surfaces formed at the time of punching (to be described later) (steps S4 and S5). As shown in FIG. 5, the surface roughness of the lower cut surface 44b is larger than the surface roughness of the upper cut surface 44a. That is, the lower cut surface 44b is rougher than the upper cut surface 44a.

  A curved surface portion 44c (so-called “sag”) resulting from the punching process is formed at the upper end portion of the upper cut surface 44a. Further, a business trip portion 44d (so-called “burr”) resulting from the punching process is formed at the lower end of the lower cut surface 44b. The business trip part 44d protrudes downward from the lower surface of the disk part 441. In the present embodiment, since the curved surface portion 44c is located on the upper surface side and the business trip portion 44d is located on the lower surface side, the lower surface of the lid portion 141 of the clamper 14 and the upper surface of the disc portion 441 of the yoke 44 Can be approached well.

  FIG. 6 is a photograph of the yoke 44 manufactured according to the manufacturing procedure described later. In FIG. 6, it can be seen that an upper cut surface 44a and a lower cut surface 44b having a larger surface roughness than the upper cut surface 44a are formed on the outer peripheral surface of the disc portion 441. It can also be seen that a curved surface portion 44c is formed at the upper end portion of the upper cut surface 44a and a business trip portion 44d is formed at the lower end portion of the lower cut surface 44b.

(C) Shape of inner peripheral surface Returning to FIG. The inner peripheral surface of the yoke 44 has an upper inner peripheral surface 44e formed from the upper end to a predetermined height position, and a lower inner peripheral surface 44f formed from the predetermined height position to the lower end. Have The upper inner peripheral surface 44e forms a space in which the convex portion 142 of the clamper 14 is inserted. The lower inner peripheral surface 44f is a surface fixed to the outer peripheral surface of the shaft 41 by press-fitting.

  In the present embodiment, the diameter d3 of the upper inner peripheral surface 44e is set to a sufficient size to avoid contact with the convex portion 142 of the clamper 14. On the other hand, the diameter d4 of the lower inner peripheral surface 44f is set slightly smaller than the diameter d3 of the upper inner peripheral surface 44e so as to be suitable for press-fitting with the shaft 41.

  A curved surface portion 44 g that connects the upper inner peripheral surface 44 e and the upper surface of the disc portion 441 is formed at the upper end portion of the inner peripheral surface of the yoke 44. The curved surface portion 44g has a shape in which the inner diameter gradually widens upward. Such a curved surface portion 44g prevents the upper end portion of the upper inner peripheral surface 44e from protruding above the upper surface of the disc portion 441. Therefore, the lower surface of the lid portion 141 of the clamper 14 and the upper surface of the disc portion 441 of the yoke 44 are in good surface contact.

  If the curved surface portion 44g is too large, the contact area between the yoke 44 and the clamper 14 becomes small, and the attractive force between the yoke 44 and the clamper 14 may be reduced. On the other hand, if the curved surface portion 44g is too small, the convex portion 142 may be damaged when the convex portion 142 of the clamper 14 comes into contact with the curved surface portion 44g. Therefore, it is desirable to set the curved surface portion 44g to an appropriate size in order to prevent damage to the convex portion 142 of the clamper 14 while ensuring a contact area between the yoke 44 and the clamper 14. Specifically, the radial dimension d5 of the curved surface portion 44g is preferably set to a value of 0.3 mm or more and 1.0 mm or less, and if set to a value of 0.7 mm or more and 0.9 mm or less, More preferred. Further, the axial dimension d6 of the curved surface portion 44g is preferably set to a value of 0.3 mm or more and 0.6 mm or less, and more preferably set to a value of 0.5 mm or more and 0.6 mm or less.

  Further, a chamfered portion 44 h is formed on the inner edge portion of the lower surface of the cylindrical portion 442 of the yoke 44. The chamfered portion 44h is a tapered surface whose inner diameter gradually increases downward. When the shaft 41 is press-fitted into the cylindrical portion 442 of the yoke 44, the radial position of the shaft 41 with respect to the cylindrical portion 442 can be easily determined using the chamfered portion 44h. Moreover, compared with the case where there is no chamfer 44h, damage to both members when the shaft 41 is press-fitted into the cylindrical portion 442 can be suppressed.

<2-4. Yoke manufacturing procedure>
As described above, the yoke 44 is obtained by press-molding a metal plate. Below, the manufacturing procedure of the yoke 44 by press molding is demonstrated, referring the flowchart of FIG. 7, and the longitudinal cross-sectional views of FIGS.

  When manufacturing the yoke 44, first, the center hole 51 is formed in the metal plate 5 which is the base material of the yoke 44 (step S1, state of FIG. 8). Specifically, a circular hole smaller than the inner diameter of the yoke 44 (d3 and d4 above) is obtained by horizontally supporting the metal plate 5 and vertically passing a drilling tool 61 through the metal plate 5. Form.

  Next, burring is performed to form a cylindrical portion 442 protruding downward on the metal plate 5 (step S2, state of FIG. 9). Specifically, a substantially cylindrical tool 62 for burring is applied to the upper surface of the metal plate 5 from above the center hole 51, and the portion around the center hole 51 of the metal plate 5 is bent downward while being bent. Thus, the cylindrical portion 442 is formed.

  As shown in FIG. 9, the outer peripheral surface of the tool 62 has an upper outer peripheral surface 621 and a lower outer peripheral surface 622 having a smaller diameter than the upper outer peripheral surface 621. For this reason, the inner peripheral surface of the cylindrical part 442 formed by burring has an upper inner peripheral surface 44e and a lower inner peripheral surface 44f having a smaller diameter than the upper inner peripheral surface 44e.

  Subsequently, the bottom surface of the cylindrical portion 442 is chamfered (step S3, state of FIG. 10). Here, the axial length of the cylindrical portion 442 is adjusted by hitting a tool 63 for surface hitting against the lower surface of the cylindrical portion 442.

  As shown in FIG. 10, a frustoconical protrusion 631 is formed at the center of the upper surface of the tool 63. A tapered surface is formed on the outer peripheral edge of the protruding portion 631 along the inner peripheral edge of the lower surface of the cylindrical portion 442. For this reason, a chamfered portion 44h is formed at the inner edge portion of the lower surface of the cylindrical portion 442 after chamfering.

  Then, the 1st and 2nd punching is performed with respect to the metal plate 5, and the disc part 441 is formed (step S4-S5, the state of FIG. 11). Specifically, by punching a punching tool (not shown) from above the metal plate 5, the portion 52 on the outer side in the radial direction than the portion to be the disc portion 441 of the metal plate 5 is removed.

  FIG. 12 is a top view of the yoke 44 obtained after the first and second punching. In the first punching and the second punching described above, different portions A1 and A2 are punched in the circumferential direction, respectively. For this reason, as shown in FIG. 12, the outer peripheral surface of the disc part 441 of the yoke 44 includes the first cut surface 44i formed by the first punching and the second cut surface formed by the second punching. 44j.

  The first cut surface 44i and the second cut surface 44j are adjacent to each other in the circumferential direction. Further, the diameter (distance from the center axis 9) r1 of at least the end portion in the circumferential direction of the first cut surface 44i is smaller than the diameter (distance of the center axis 9 empty) r2 of the second cut surface 44j. Is set. For this reason, it is prevented that a portion protruding radially outward from the second cut surface 44j is formed at the boundary between the first cut surface 44i and the second cut surface 44j. Thereby, it can prevent that the outer peripheral surface of the disc part 441 of the yoke 44 contacts the inner peripheral surface of the cylindrical part 433 of the cone 43.

<3. Modification>
As mentioned above, although main embodiment of this invention was described, this invention is not limited to said embodiment.

  In the above embodiment, the shaft 41 and the yoke 44 are fixed by press fitting, but the shaft 41 and the yoke 44 may be fixed by other methods such as shrink fitting.

  In the above embodiment, the clamp magnet 144 is fixed to the clamper 14, but the clamp magnet 144 may be provided on the yoke 44 side. However, from the viewpoint of reducing the size, weight, and cost of the chucking device 4, it is desirable to provide the clamp magnet 144 on the clamper 14 side as in the above embodiment.

  In the above embodiment, the turntable 42 and the cone 43 are separate members, but they may be configured as an integral member. That is, a single member having a disk mounting portion having a mounting surface for mounting the disk 90 and a disk inner edge support portion having a support surface for supporting the inner edge portion of the disk 90 is prepared. The member may be used in place of the turntable 42 and the cone 43 described above.

  In FIG. 12, the entire first cutting surface 44i is located radially inward of the second cutting surface. However, as shown in FIG. Only the vicinity of the end adjacent to the surface 44j may be located radially inward of the second cut surface 44j.

  In the above embodiment, the first cut surface 44i is formed by the first punching (step S4), and then the second cut surface 44j is formed by the second punching (step S5). The first cutting surface 44i and the second cutting surface 44j may be formed at the same time by simultaneously performing the punching and the second punching.

  In the above embodiment, the chucking device 4 for the optical disk 90, the brushless motor 13, and the disk drive device 1 have been described. However, the present invention provides a chucking device for other disks such as a magnetic disk, and a brushless motor. It can also be applied to disk drive devices.

  INDUSTRIAL APPLICABILITY The present invention can be used for a chucking device that holds a disc, a brushless motor that includes the chucking device, and a disk drive device that includes the brushless motor.

DESCRIPTION OF SYMBOLS 1 Disc drive device 2 Static part 3 Rotating part 4 Chucking device 9 Center shaft 13 Brushless motor 14 Clamper 15 Recording / reproducing part 41 Shaft 42 Turntable 43 Cone 44 Yoke 44a Upper cut surface 44b Lower cut surface 44c Curved surface part 44d Business trip part 44e Upper inner peripheral surface 44f Lower inner peripheral surface 44g Curved surface portion 44h Chamfered portion 44i First cut surface 44j Second cut surface 90 Disc 144 Clamp magnet 423 Rubber member 441 Disk portion 442 Cylindrical portion

Claims (8)

A shaft arranged vertically along the central axis;
A disk mounting portion having a mounting surface for mounting a disk-shaped disk fixed to the shaft and having a circular hole in the center;
On the upper side of the disc mounting portion, a disc inner edge support portion having a support surface for supporting the inner edge portion of the disc;
A magnetic member fixed to the shaft;
With
The magnetic member has a disc portion having a circular hole in the center, and a cylindrical portion that extends downward from an inner edge portion of the disc portion and is fixed to the shaft.
The chucking device in which the thickness in the radial direction of the cylindrical portion is thinner than the thickness in the axial direction of the disk portion. The chucking device according to claim 1,
The chucking device, wherein the magnetic member is a press-molded product and has a projecting portion protruding downward from a lower end portion of an outer peripheral surface of the disc portion. The chucking device according to claim 1 or 2,
The chucking device, wherein the magnetic member has a curved surface portion that connects an upper surface of the disk portion and an inner peripheral surface of the disk portion, and has an inner diameter that gradually increases upward. The chucking device according to any one of claims 1 to 3,
The inner peripheral surface of the magnetic member is
An upper inner peripheral surface formed from the upper end to a predetermined height position;
A lower inner peripheral surface formed from the predetermined height position to the lower end, and having a smaller diameter than the upper inner peripheral surface;
Chucking device having The chucking device according to any one of claims 1 to 4,
The chucking device, wherein the magnetic member has a chamfered portion formed at an inner edge portion of a lower end portion of the cylindrical portion. The chucking device according to any one of claims 1 to 5,
The outer peripheral surface of the disk portion of the magnetic member is
A first cut surface;
A second cut surface formed adjacent to the first cut surface in the circumferential direction;
Have
A chucking device, wherein a diameter of at least one of the first cut surface and the second cut surface in the vicinity of an end portion in the circumferential direction is smaller than the other diameter of the first cut surface and the second cut surface. A stationary part;
A rotating part supported rotatably about the central axis with respect to the stationary part;
A torque generator that generates a torque about the central axis between the stationary part and the rotating part;
The chucking device according to any one of claims 1 to 6, wherein the chucking device rotates together with the rotating unit.
Brushless motor with A brushless motor according to claim 7;
A clamper that presses the disk toward the mounting surface by an attractive force between the magnetic member,
A recording / reproducing unit that performs at least one of reading and writing of information with respect to the disc held in the chucking device;
A disk drive device comprising: