JP2010170632A - Disk supporting member, chucking device, brushless motor, and disk drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a size in the axis direction of a disk supporting member by preparing the disk supporting member by resin molding and while securing a space for storing a magnetic member. <P>SOLUTION: The disk supporting member is a resin molded product having a storage part 431 storing the magnetic member at the periphery of the center axis, and a guide 433a having a guide plane guiding an inner edge of a disk in a radial direction outside the storage part 431; a gate cut part 434 of the resin molding is formed at the back of the guide part 433a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a disk support member, 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.

Such a brushless motor has a turntable that contacts the inner edge of the disk and supports the disk. A brushless motor provided with a turntable is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-110919.
JP 2004-110919 A

  Some turntables have an accommodating recess for accommodating an attracting means such as an annular permanent magnet inside the guide positioning protrusion for guiding the disk. However, if such a turntable is to be produced by injection molding of resin, the trace of the molten resin flow path at the time of injection molding and the above-described housing recess must be formed in one turntable.

  In particular, a portion of the turntable where the trace of the molten resin flow path is formed needs a certain thickness in order to prevent deformation at the time of mold release. For this reason, the dimension of the axial direction of the turntable becomes large due to the trace of the molten resin flow path and the accommodating recess, and there is a problem that it is difficult to make the turntable thin.

  An object of the present invention is to provide a disc support member that is manufactured by resin molding and that can suppress a dimension in the axial direction of the disc support member while securing a space for accommodating suction means. Furthermore, the present invention provides a chucking device, a brushless motor, and a disk drive device including the same.

  In order to solve the above-mentioned problem, the first invention of the present application is a disk support member, wherein a housing part that houses a magnetic member is disposed around a central axis, and an inner edge part of the disk is disposed radially outside the housing part. And a guide part having a guide surface for guiding, and a resin-cut gate cut part is formed on the back surface of the guide part.

  According to the first invention of the present application, the disk support member has a resin-cut gate cut portion on the back surface of the guide portion located radially outside the housing portion. For this reason, the disk support member is manufactured by resin molding, and the axial dimension of the disk support member can be suppressed while securing a space for accommodating the magnetic member.

FIG. 1 is a diagram conceptually showing a disk support member. 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 cone. FIG. 5 is a bottom view of the cone. FIG. 6 is a longitudinal sectional view partially showing a state when a cone is manufactured by injection molding. FIG. 7 is a longitudinal sectional view partially showing a state when a cone is produced by injection molding. FIG. 8 is an enlarged longitudinal sectional view of the gate cut portion and the vicinity thereof. FIG. 9 is a perspective view of the second guide portion as seen from the back side.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<1. Chucking Device According to One Embodiment>
FIG. 1 is a diagram conceptually showing a disk support member 43 according to an embodiment of the present invention. The disk support member 43 is a member for supporting the disk by contacting the inner edge of the disk having a circular hole in the center.

  As shown in FIG. 1, the disk support member 43 is formed on the outer side of the accommodating portion 431 formed around the central axis 9 and the radial direction of the accommodating portion 431 (the direction orthogonal to the central axis 9; the same applies hereinafter). The resin molded product having the guide portion 433. The accommodating portion 431 forms a space for accommodating a magnetic member used to hold the disk in the axial direction (the direction along the central axis 9; the same applies hereinafter). The guide portion 433 has a guide surface 433a for guiding the inner edge portion of the disc.

  The disk support member 43 has a resin-cut gate cut portion 434 on the back surface of the guide portion 433. Therefore, the disk support member 43 can be produced by resin molding, a space for accommodating the magnetic member can be secured, and the axial dimension of the disk support member 43 can be suppressed. In the present embodiment, the “back surface” of the guide portion 433 is located on the radially outer side with respect to the space for accommodating the magnetic member and located on the radially inner side with respect to the outermost peripheral portion of the guide portion 433. The whole lower surface of the guide part 433 is indicated.

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

  Below, the direction along the central axis 9 is the vertical direction, the clamper 13 side is “up” and the rotor holder 42 side is “down” with respect to the disc 90 held by the chucking device 4. The positional relationship will be described. However, this is defined only in the vertical direction for convenience of explanation, and when the disk support member, chucking device, brushless motor, and disk drive device of the present invention are mounted on an actual device. The installation posture is not limited.

  FIG. 2 is a longitudinal sectional view of the disk drive device 1. The disk drive device 1 is a device that reads information from the disk 90 or writes information to the disk 90 while rotating the optical disk 90 (hereinafter simply referred to as “disk 90”) about the central axis 9. As shown in FIG. 2, the disk drive device 1 mainly includes a device housing 11, a brushless motor 12, a clamper 13, and a recording / reproducing unit 14.

  The device housing 11 is a housing that houses the brushless motor 12, the clamper 13, and the recording / reproducing unit 14 therein. The apparatus housing 11 is formed with an opening 11a for carrying in and out the disk 90. The brushless motor 12 is fixed to a chassis 15 provided inside the apparatus housing 11. Further, the brushless motor 12 has a chucking device 4 that holds a disk 90 on the upper portion thereof. The disk 90 carried into the apparatus housing 11 is held between the chucking apparatus 4 and the clamper 13 and is rotated about the central axis 9 by the brushless motor 12.

  The recording / reproducing unit 14 moves the optical pickup unit 141 along the recording surface of the disk 90 rotated by the brushless motor 12 to read information from the disk 90 or write information to the disk 90. Note that the optical pickup unit 141 of the recording / reproducing unit 14 may perform both reading and writing of information with respect to the disk 90.

<2-2. Configuration of brushless motor>
Next, the configuration of the brushless motor 12 will be described. FIG. 3 is a longitudinal sectional view of the brushless motor 12. As shown in FIG. 3, the brushless motor 12 includes a stationary part 2 fixed to the chassis 15 of the disk drive device 1, a rotating part 3 that is rotatably supported with respect to the stationary part 2, and a rotating part 3. On the upper side, a chucking device 4 that rotates together with the rotating unit 3 while holding the disk 90 is provided.

  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 231a, and a coil 232 wound around each tooth portion 231a.

  The rotating unit 3 mainly includes a shaft 41, a rotor holder 42, and a rotor magnet 31. The shaft 41 is a substantially cylindrical member disposed in the vertical direction along the central axis 9. The rotor holder 42 is a member that is fixed to the shaft 41 and rotates together with the shaft 41. The rotor magnet 31 is fixed to the rotor holder 42. The rotor magnet 31 has an annular shape, and the inner peripheral surface thereof is a magnetic pole surface facing the end surface of the teeth portion 231a 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 teeth 231 a of the stator core 231. Then, circumferential torque is generated by the action of magnetic flux between the teeth portion 231a and the rotor magnet 31, and the rotating portion 3 rotates about the central axis 9 with respect to the stationary portion 2.

  The chucking device 4 includes a shaft 41 and a rotor holder 42 as members common to the rotating unit 3. The chucking device 4 further includes a cone 43, a clamp magnet 44, and a back yoke 45.

  The rotor holder 42 includes a first cylindrical portion 421 that is fixed to the shaft 41, a flange portion 422 that extends radially outward from the lower end portion of the first cylindrical portion 421, and a second cylindrical portion that extends downward from the outer edge portion of the flange portion 422. 423. An annular rubber member 424 is fixed to the upper surface 42 a of the flange portion 422. The disk 90 is placed on the flange portion 422 with its lower surface in contact with the upper surface 42b of the rubber member 424. That is, in the present embodiment, the rotor holder 42 and the rubber member 424 integrally constitute a disk mounting portion, and the upper surface 42b of the rubber member 424 is a disk mounting surface.

  The cone 43 is a member (disc support member) for supporting the edge of a circular hole formed at the center of the disc 90, that is, the inner edge of the disc 90. The cone 43 is fixed to the rotor holder 42. More specifically, it is preferable that the cone 43 is in contact with the outer peripheral surface of the first cylindrical portion 421 of the rotor holder 42 and is opposed to the upper surface of the flange portion 422 of the rotor holder 42 in the axial direction via a minute gap. The cone 43 includes a storage portion 431 that stores the clamp magnet 44 and the back yoke 45, and a first guide portion 432 and a second guide portion 433 that are positioned on the radially outer side of the storage portion 431. Note that the cone 43 may be in contact with the upper surface of the flange portion 422 of the rotor holder 42.

  The detailed shape and the like of the cone 43 will be described later.

  The clamp magnet 44 and the back yoke 45 are magnetic members accommodated inside the accommodating portion 431 of the cone 43. The clamp magnet 44 is a magnet that generates an axial magnetic flux. The back yoke 45 is a magnetic material for improving the directivity of the magnetic field generated from the clamp magnet 44. The clamp magnet 44 and the back yoke 45 generate a magnetic attractive force between the clamper 13 and the clamper 13, thereby attracting the clamper 13 toward the rotor holder 42.

  When holding the disk 90, the clamper 13 is attracted to the rotor holder 42 side by a magnetic attraction between the clamp magnet 44 and the clamper 13. As a result, the disk 90 is sandwiched between the upper surface 42 b of the rubber member 424 and the lower surface of the clamper 13. The first guide portion 432 of the cone 43 abuts on the inner edge of the disc 90 and regulates the radial position of the disc 90 so that the center of the disc 90 is located on the central axis 9. Further, the upper surface 42a of the rubber member 424 and the lower surface of the clamper 13 are in contact with the lower surface and the upper surface of the disc 90, respectively, and restrict the axial position and posture of the disc 90.

<2-3. Detailed shape of cone>
Subsequently, a more detailed shape of the cone 43 will be described. 4 and 5 are a longitudinal sectional view and a bottom view of the cone 43, respectively. 4 corresponds to a cross-sectional view of the cone 43 as viewed from the position IV-IV in FIG.

(A) About the overall shape of the cone As described above, the cone 43 includes the accommodating portion 431 that accommodates the clamp magnet 44 and the back yoke 45, and the first edge that guides the inner edge portion of the disk 90 on the radially outer side of the accommodating portion 431. A guide portion 432 and a second guide portion 433. The cone 43 is a resin molded product obtained by resin injection molding. For this reason, many cones 43 can be produced quickly and inexpensively.

  As shown in FIG. 4, the accommodating portion 431 of the cone 43 includes a cylindrical portion 431a and a flat plate portion 431b that extends radially outward from the lower end portion of the cylindrical portion 431a. As described above, the inner peripheral surface of the cylindrical portion 431 a abuts on the outer peripheral surface of the first cylindrical portion 421 of the rotor holder 42. The lower surface of the flat plate portion 431b faces the upper surface of the flange portion 422 of the rotor holder 42 in the axial direction with a minute gap. A space 431c for accommodating the clamp magnet 44 and the back yoke 45 is secured on the outer side in the radial direction of the cylindrical portion 431a and above the flat plate portion 431b.

  The first guide part 432 and the second guide part 433 are located on the radially outer side than the accommodating part 431 of the cone 43. As shown in FIG. 5, in the present embodiment, it is preferable that the five first guide portions 432 and the five second guide portions 433 are arranged alternately and at equal intervals in the circumferential direction.

  The first guide portion 432 includes a first guide surface 432a for guiding the inner edge portion of the disc 90 to determine the radial position of the disc 90 when the disc 90 is loaded, and the inner edge portion of the disc 90 after being loaded. And a support surface 432b for supporting the disk 90 in contact with the disk. When the disc 90 is mounted, the tip end portion of the first guide portion 432 is slightly bent inward in the radial direction. As a result, the support surface 432b comes into good contact with the inner edge of the disk 90 regardless of the size error of the disk 90.

  The second guide portion 433 has a second guide surface 433a for guiding the inner edge of the disc 90 to determine the radial position of the disc 90 when the disc 90 is mounted, and a lower portion of the second guide surface 433a. The outer peripheral surface 433b is formed. It is preferable that the outer peripheral surface 433b of the second guide portion 433 is located slightly inside in the radial direction with respect to the support surface 432b of the first guide portion 432.

(B) Position of Gate Cut Part As described above, the cone 43 is obtained by resin injection molding. 6 and 7 are longitudinal cross-sectional views partially showing a state in which the cone 43 is produced by injection molding.

  When injection molding is performed, first, molten resin is caused to flow into a cavity 53 formed between the stationary mold 51 and the movable mold 52. The molten resin flows into the cavity 53 from the gate 51a formed in the portion corresponding to the back surface of the second guide part 433 of the stationary mold 51 (state of FIG. 6). Then, after the molten resin is solidified in the cavity 53, the movable side mold 52 is moved with respect to the stationary side mold 51 to break the resin in the gate 51 a, and the stationary side mold 51 and the cone 43. Are released (state of FIG. 7). In FIG. 7, the movable mold 52 is moved downward with respect to the stationary mold 51, but is not limited to this. The moving direction of the movable side mold 52 relative to the stationary side mold 51 can be various methods without departing from the scope of the present invention.

  When the stationary mold 51 and the cone 43 are released from each other, a convex gate cut portion 434 is formed on the back surface (lower surface) of the second guide portion 433 of the cone 43. In the present embodiment, it is preferable that such a gate cut portion 434 is formed on the back surface of the second guide portion 433 that is located on the outer side in the radial direction than the accommodating portion 431. For this reason, the space for accommodating the clamp magnet 44 and the back yoke 45 can be secured while suppressing the axial thickness of the flat plate portion 431b. Thereby, the dimension of the whole cone 43 in the axial direction can also be suppressed. In the present embodiment, the “back surface” of the second guide portion 433 is located radially outside the space 431 a for accommodating the clamp magnet 44 and the back yoke 45, and the second guide portion 433. The whole lower surface of the 2nd guide part 433 located in a radial inside rather than an outermost peripheral part is pointed out.

  Further, as shown in FIG. 4, the axial length d1 of the second guide portion 433 is longer than the axial length d2 of the flat plate portion 431b. That is, the gate cut portion 434 is formed in a portion of the second guide portion 433 and the flat plate portion 431b that is relatively thick in the axial direction. For this reason, when the gate cut part 434 is fractured in the injection molding, it is possible to prevent the part including the gate cut part 434 from being deformed. Further, a concave portion 435 described later can be formed around the gate cut portion 434 without increasing the axial dimension of the cone 43 excessively.

  The gate cut part 434 is formed on the back surface of the second guide part 433 having a large width in the circumferential direction among the first guide part 432 and the second guide part 433. For this reason, the gate cut part 434 can be formed comparatively easily. In addition, the gate 51a of the stationary mold 51 can be set to a sufficient size.

  In the present embodiment, it is preferable that the gate cut portion 434 is formed in each of the second guide portions 433. That is, in the present embodiment, the five gate cut portions 434 are evenly arranged around the central axis 9. For this reason, molten resin can be made to flow uniformly into the cavity 53 from the gate 51a equally arrange | positioned around the central axis 9 at the time of resin molding. In addition, since the plurality of gate cut portions 434 are evenly arranged around the central axis 9, it is possible to prevent the center of gravity of the cone 43 from being biased.

(C) About the shape of the gate cut part and its vicinity FIG. 8: is an enlarged longitudinal cross-sectional view of the gate cut part 434 and its vicinity. FIG. 9 is a perspective view of the second guide portion 433 as viewed from the back side.

  As shown in FIGS. 8 and 9, the gate cut portion 434 includes a substantially cylindrical thick portion 434 a that protrudes downward from the back surface of the second guide portion 433, and a little more from the lower end surface of the thick portion 434 a. And a fracture portion 434b projecting downward. The fracture portion 434b has a fracture surface having a larger surface roughness (rougher) than the back surface of the second guide portion 433, which is formed by breaking the resin in the gate 51a during injection molding.

  Further, a recess 435 is formed on the back surface of the second guide part 433, and the gate cut part 434 is formed inside the recess 435. And the depth of the recessed part 435 and the length of the axial direction of the gate cut part 434 are set so that the lowest part of the fracture | rupture part 434b may be located above the lower surface of the flat plate part 431b. For this reason, it can prevent that the fracture | rupture part 434b contacts with the upper surface of the flange part 422 of the rotor holder 42. FIG.

  The concave portion 435 includes a first groove portion 435a formed on the outer side and the inner side in the radial direction of the thick portion 434a, and a second groove portion 435b adjacent to the thick portion 434a in the circumferential direction. The 1st groove part 435a is a groove | channel shallower than the 2nd groove part 435b formed in the substantially circular arc shape along the side surface of the thick part 434a. Sites 436a and 436b adjacent to the radially outer side and the radially inner side of the first groove portion 435a are partially cut away by the first groove portion 435a. The second guide part 433 includes a thin part 437 that is adjacent to the thick part 434a in the circumferential direction and has a smaller axial thickness than the thick part 434a. The upper surface of the thin portion 437 is the bottom surface of the second groove portion 435b.

  The first groove portion 435a and the second groove portion 435b reduce the difference in axial thickness between the first guide portion 432 and the second guide portion 433. Due to the formation of the first groove portion 435a and the second groove portion 435b, when the molten resin is solidified in the injection molding, the surface of the cone 43 is recessed due to a partial difference in thickness (so-called sink). Is prevented from occurring.

  Further, the side surface 435c of the first groove portion 435a is a tapered surface whose inner diameter gradually increases downward. For this reason, the stationary mold 51 and the cone 43 can be easily released during injection molding.

  The material of the cone 43 is preferably a polycarbonate resin, but is not limited to this. For example, polyacetal, nylon, polyamideimide (PAI), polyetheretherketone (PEEK), thermoplastic polyimide (TPI), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyether A thermoplastic resin such as imide (PEI) can be used. It is also possible to use a material in which two or more kinds of thermoplastic resins are mixed. Moreover, it is also possible to use thermosetting resins, such as a phenol resin, and the mixture of a thermoplastic resin and a thermosetting resin.

<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 five gate cut portions 434 are formed in the cone 43, but the number of the gate cut portions 434 may be one to four, or may be six or more.

  Further, in the above embodiment, the first groove portion 435a is formed on the outer side and the inner side in the radial direction of the thick portion 434a. It may be formed only on one side.

  In the above-described embodiment, the clamp magnet 44 is provided on the chucking device 4 side of the clamper 13 and the chucking device 4. However, the clamp magnet 44 may be provided on the clamper 13 side.

  In the above embodiment, the clamp magnet 44 and the back yoke 45 are accommodated in the accommodating portion 431 of the cone 43, but only one of them may be accommodated in the accommodating portion 431 of the cone 43.

  In the above embodiment, the cone 43 is fixed to the shaft 41 via the rotor holder 42, but the cone 43 may be directly fixed to the shaft 41. Further, the cone 43 may be slidable up and down along the shaft 41.

  In the above embodiment, the cone 43 for the optical disc 90, the chucking device 4, the brushless motor 12, and the disc drive device 1 have been described. However, the present invention can also be applied to other disk support members, chucking devices, brushless motors, and disk drive devices that support magnetic disks and the like.

  The present invention can be used for a disk support member, and can also be used for a chucking device, a brushless motor, and a disk drive device including the same.

DESCRIPTION OF SYMBOLS 1 Disc drive device 2 Static part 3 Rotating part 4 Chucking device 9 Center shaft 11 Device housing 12 Brushless motor 13 Clamper 14 Recording / reproducing part 41 Shaft 42 Rotor holder 43 Cone 44 Clamp magnet 45 Back yoke 90 Disk 424 Rubber member 431 Housing part 431a Cylindrical part 431b Flat plate part 432 First guide part 433 Second guide part 434 Gate cut part 434a Thick part 434b Breaking part 435 Recessed part 435a First groove part 435b Second groove part 435c Side face

Claims (13)

An accommodating portion for accommodating a magnetic member around the central axis;
A guide portion having a guide surface for guiding an inner edge portion of the disk on the radially outer side of the housing portion;
A resin molded product having
A disk support member in which a resin-molded gate cut portion is formed on the back surface of the guide portion. The disk support member according to claim 1,
The accommodating portion includes a flat plate portion extending in a radial direction with respect to a central axis,
The length of the guide portion in the axial direction is a disc support member longer than the length of the flat plate portion in the axial direction. In the disk support member according to claim 1 or 2,
A disc support member in which a recess is formed on the back surface of the guide portion, and the gate cut portion is formed inside the recess. In the disk support member according to any one of claims 1 to 3,
The gate cut part is
A thick wall protruding in the axial direction;
A disc support member having a fracture portion formed on an end face in the axial direction of the thick portion. The disk support member according to claim 4,
The guide portion is
A disk support member having a thin portion adjacent to the thick portion in the circumferential direction and having a smaller axial thickness than the thick portion. In the disk support member according to claim 5,
The thick part has a substantially cylindrical shape,
On the back surface of the guide portion,
In at least one of the radially outer side and the radially inner side of the thick part, a first groove part formed in an arc shape along the side surface of the thick part;
A second groove having the upper surface of the thin portion as a bottom surface;
Is formed,
The first groove portion is a disc support member that is shallower than the second groove portion. The disk support member according to claim 6,
The first groove portion is a disk support member having a tapered side surface whose inner diameter gradually increases toward the opening side. In the disk support member according to any one of claims 1 to 7,
The guide portion is
A first guide portion that contacts the inner edge of the disc in a state where the disc is supported;
A second guide portion that does not contact the inner edge of the disc in a state where the disc is supported;
Have
A disk support member in which the gate cut portion is formed on the back surface of the second guide portion. The disk support member according to claim 8,
A disk support member in which a circumferential width of the second guide portion is larger than a circumferential width of the first guide portion. In the disk support member according to any one of claims 1 to 9,
A disk support member in which a plurality of the gate cut portions are evenly arranged around the central axis. A shaft arranged vertically along the central axis;
A disk mounting portion fixed to the shaft and having a mounting surface for mounting the disk;
The disk support member according to any one of claims 1 to 10, which is disposed on an upper side of the disk mounting portion,
Chucking device equipped with. 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 claim 11 that rotates together with the rotating unit;
Brushless motor with The brushless motor according to claim 12,
A clamper that presses the disk toward the mounting surface;
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:

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