JPH0684560U - Spindle motor for disk drive - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a disk drive spindle motor that is inexpensive and can sufficiently cope with flattening. [Structure] A rotor case 2 to which a drive magnet 1 is fixed, and a stator coil 3 facing the drive magnet 1.
In a disk drive spindle motor including a hub for mounting a disk, the spindle 5 is press-fitted into the burring portion 4 provided in the central portion of the rotor case 2, and the convex portion formed on the outer peripheral portion of the burring portion 4 is pressed. Coating 15 was applied to the surface of No. 6 to prepare a disk mounting surface. As the coating 15, a coating agent may be applied, or a coated tape may be attached.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle motor used to drive, for example, a magnetic disk.

[0002]

[Prior art]

 Spindle motors and the like are known as motors for rotationally driving magnetic disks and the like. 9 and 10 show an example of such a disk driving spindle motor. 9 and 10, the cylindrical bearing holder 52 has a flange portion 52a on the outer periphery thereof, and the stator core 47 is attached to the lower surface of the flange portion 52a. The stator core 47 has a plurality of salient poles on the outer circumference, and a stator coil 43 is wound around each salient pole. A hole communicating with the bearing holder 52 and the stator core 47 is formed, and a screw 51 is inserted into this hole. The screw 51 penetrates the bearing holder 52 and the stator core 47 and is screwed into the substrate 48. A spacer 50 is attached between the stator core 47 and the substrate 48 to secure a space for winding the stator coil 43 around the salient pole of the stator core 47. By screwing the tip of the screw 51 into the substrate 48, the flange portion 52a, the stator core 47, and the spacer 50 are pressed against the substrate 48 side by the head of the screw 51 and are integrally fixed.

On the inner peripheral surface of the bearing holder 52, two upper and lower sintered oil-impregnated type bearings 49, 49 are fitted and fixed. A through hole is formed in the center of each of the bearings 49, 49, and a spindle 45 is inserted through the through hole. The lower end of the spindle 45 is in contact with a thrust bearing 52 provided in the center of the substrate 48.

A hub base 58, on which a magnetic disk or the like is placed, is attached to the upper end of the spindle 45. A cup-shaped rotor case 42 is attached to the outer periphery of the hub base 58. As shown in FIG. 10, a caulking portion 58a is formed on the lower end of the outer periphery of the hub base 58, and the caulking portion 58a caulks an edge portion of the rotor case 42 to fix the rotor case 42 to the hub base 58. The hub base 58 is formed by cutting brass or the like, and the upper surface of the hub base 58 on which the hub 60 of the disk 59 is mounted is coated with fluorine or the like to reduce frictional resistance. There is.

In FIG. 9, the cup-shaped rotor case 42 is configured to cover the stator core 47 from the upper side. A drive magnet 41 is mounted inside the peripheral wall of the rotor case 42. The drive magnet 41 is opposed to the salient pole of the stator core 47 with a gap, and the drive magnet 41 and the rotor case 42 are energized by controlling the energization of the stator coil 43 wound around the salient pole, and the spindle 45 is rotated. Is driven to rotate.

[0006]

[Problems to be solved by the device]

 The hub base 58 used for the disk drive spindle motor as described above is formed by cutting brass or the like, and the surface on which the disk or the like is mounted is coated with fluorine or the like and the rotor case 42. A caulking portion 58a is formed at a portion to which is attached. Therefore, the cost of forming such a hub base 58 increases. Further, since the hub base 58 is fixed to the rotor case 42 by caulking, the runout accuracy of the drive magnet 41 and the like with respect to the spindle 45 deteriorates, which adversely affects the basic characteristics of the motor.

Further, as the flattening of the motor progresses, it becomes difficult to caulkly attach the rotor case 42 to the hub base 58, resulting in higher cost and sufficient clearance between the respective parts. It cannot be removed or the fixing structure becomes weak. Therefore, it becomes impossible to deal with flattening sufficiently.

The present invention has been made to solve the above problems, and an object thereof is to provide a disk drive spindle motor that is inexpensive and can sufficiently cope with flattening. And

[0009]

[Means for Solving the Problems]

 According to a first aspect of the present invention, there is provided a disk drive spindle motor including a rotor case to which a drive magnet is fixed, a stator coil facing the drive magnet, and a hub portion on which a disk is mounted. It is characterized in that the spindle is press-fitted into the burring portion provided on the disk portion and the surface of the convex portion formed on the outer peripheral portion of the burring portion is coated to form the disk mounting surface.

The invention according to claim 2 is characterized in that a solid lubricant is applied to the coating.

The invention according to claim 3 is characterized in that a coated tape is attached to the coating.

[0012]

[Action]

 The central convex portion of the rotor case is used as the disk mounting surface. The coating applied to the surface of the convex portion reduces the frictional resistance with the disc hub, and allows the disc hub to be positioned smoothly. By pressing the spindle into the burring portion formed in the center of the convex portion of the rotor case, the spindle and the rotor case are directly fixed.

[0013]

【Example】

 An embodiment of a disk driving spindle motor according to the present invention will be described below with reference to the drawings. 1 and 2, the cylindrical bearing holder 12 has a flange portion 12a on the outer circumference, and a stator core 7 is attached to the lower surface of the flange portion 12a. The stator core 7 has a plurality of salient poles on the outer circumference, and the stator coil 3 is wound around each salient pole. A hole communicating with the bearing holder 12 and the stator core 7 is formed, and a screw 11 is inserted into this hole. The screw 11 penetrates the bearing holder 12 and the stator core 7 and is screwed into the substrate 8. A spacer 10 for securing a space for winding the stator coil 3 on the salient pole of the stator core 7 is attached between the stator core 7 and the substrate 8, and the screw 51 also penetrates the spacer 10. . By screwing the tip of the screw 51 into the substrate 8, the flange portion 12a of the bearing holder 12, the stator core 7, and the spacer 10 are sandwiched between the head portion of the screw 11 and the substrate 8 and are fixed integrally.

A sintered oil-impregnated bearing 9 is fitted and fixed to the inner peripheral surface of the bearing holder 12. The bearing 9 has a through hole formed in the center thereof, and the spindle 5 is inserted into the through hole. The lower end of the spindle 5 is in contact with a thrust bearing 14 provided in the center of the substrate 8.

A cup-shaped rotor case 2 is attached to the upper end of the spindle 5. At the center of the rotor case 2, there is formed a convex portion 6 projecting upward in the figure for mounting a magnetic disk or the like. The upper surface of the convex portion 6 is a flat portion, a through hole is formed in the central portion thereof, and the outer periphery of the through hole is a burring portion 4 protruding downward in a cylindrical shape. The cylindrical burring portion 4 is fixed to the upper end of the spindle 5 by press fitting. A Teflon-like sheet is attached to the upper surface of the convex portion 6 and coated with 15 to reduce frictional resistance when a disc or the like is mounted, and to position the disc hub smoothly relative to the convex portion 6. It is supposed to be done in. A drive magnet 1 is attached to the inside of the peripheral wall of the rotor case 2. The drive magnet 1 faces the salient poles of the stator core 7 with a gap, and the drive magnet 1 and the rotor case 2 are energized by controlling the energization of the stator coil 3 wound on the salient poles, and the spindle 5 is It is driven to rotate.

Next, a method of manufacturing the rotor case 2 used in the above disk drive spindle motor will be described. As shown in FIG. 3, the rotor case 2 is formed by pressing a plate material 25 such as an iron plate. At the time of punching by press working, the central portion of the bottom is drawn to form the convex portion 6 having a predetermined height and diameter. A through hole and a burring portion 4 are formed in the center of the convex portion 6. Next, a low-friction tape such as Teflon (trade name) as shown in FIG. 4 is cut out into a predetermined shape and attached to the upper surface of the convex portion 6 of the rotor case 2 as shown in FIG. The coating 15 is formed. Thus, the rotor case 2 is completed.

In the disk drive spindle motor having the above-described structure, the protrusion 6 is formed in the center of the rotor case 2, and the upper surface of the protrusion 6 is used as a hub base. Since it is not necessary to use a table, and steps such as caulking and cutting are unnecessary, manufacturing costs can be reduced. Further, since the rotor case 2 is directly attached to the spindle 5, it is possible to prevent deterioration of the swing accuracy of the drive magnet 1 and the like with respect to the spindle 5. Furthermore, since the parts are not stacked, it is possible to deal with the further flattening of the motor. In addition, although the example of the circumferentially opposed motor is described in the present embodiment, the present invention is not limited to this. For example, even in a face-to-face type motor, the same effect can be obtained by forming a convex portion and a burring portion on the rotor case and making the hub base an integral member with the rotor case.

A tape-shaped low-friction member such as Teflon is attached as the low-friction coating 15 applied to the upper surface of the convex portion 6 which is the disk mounting surface in the above embodiment. It is not limited to. For example, as shown in FIGS. 6 and 7, the roller 20 is impregnated with the coating liquid, and the roller 20 is used to apply the coating liquid on the upper surface of the convex portion 6 and harden it by heating and drying to reduce friction. Coating 15 may be formed. The coating liquid may be applied twice or three times if necessary.

The low-friction coating 15 may be formed by screen printing in which a paste-like coating material 23 is applied through a screen 22, as shown in FIG.

Further, although not shown, electroless Ni-B-PTFE composite plating is applied to the entire surface of the rotor case 6 to reduce abrasion resistance and abrasion resistance of the upper surface of the convex portion 6 on which a disk or the like is mounted. You may do it.

[0021]

[Effect of device]

 According to the present invention, the spindle is press-fitted into the burring portion provided in the center of the rotor case, and the surface of the convex portion formed on the outer periphery of the burring portion is coated to form the disk mounting surface. It is possible to provide a disk drive spindle motor that does not need to be used as a member, is inexpensive, and can sufficiently cope with flattening.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a spindle motor for driving a magnetic disk according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the main part of the same.

FIG. 3 is a perspective view showing an example of a manufacturing process of a rotor case applied to a spindle motor for driving a magnetic disk of the same.

FIG. 4 is a perspective view showing an example of a coating material applied to the magnetic disk drive spindle motor of the same.

FIG. 5 is an exploded sectional view of a rotor case applied to the magnetic disk drive spindle motor of the same.

FIG. 6 is a cross-sectional view showing an example of a roller and a coating material used for forming a coating film on a spindle motor for driving a magnetic disk according to the present invention.

FIG. 7 is a sectional view showing an example of forming the same coating layer.

FIG. 8 is a cross-sectional view showing another example of forming a coating layer of a spindle motor for driving a magnetic disk according to the present invention.

FIG. 9 is a sectional view showing an example of a conventional magnetic disk driving spindle motor.

FIG. 10 is an enlarged cross-sectional view of the main part of the same.

[Explanation of symbols]

 1 Drive magnet 2 Rotor case 3 Stator coil 4 Burring part 5 Spindle 6 Convex part 15 Coating

Claims (3)

[Scope of utility model registration request] 1. A disk drive spindle motor comprising: a rotor case to which a drive magnet is fixed; a stator coil facing the drive magnet; and a hub portion on which a disk is mounted. The disk drive spindle motor is provided at a central portion of the rotor case. A spindle motor for driving a disk, which is used as a disk mounting surface by press-fitting a spindle into the burring section and coating the surface of a convex portion formed on the outer periphery of the burring section. 2. The spindle motor for driving a disk according to claim 1, wherein the coating is a solid lubricant coating. 3. The disk drive spindle motor according to claim 1, wherein the coating is a coated tape.