Spindle motor and disk drive apparatus

Patent metadata

Field	Value
Publication number	US-9330728-B1
Application number	US-201514847059-A
Country	US
Kind code	B1
Filing date	Sep 8, 2015
Priority date	Mar 13, 2015
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A spindle motor includes a base portion molded by casting. The base portion includes a plate portion extends radially with respect to a central axis, and a wall portion arranged to extend in an axial direction from a radially outer edge of the plate portion. The wall portion includes a hole portion in which an attaching member to attach a cover member to the spindle motor is arranged, and is arranged to support at least a portion of the cover member. An inside surface of the base portion includes a metal surface subjected to a cutting process. The base portion includes a recessed portion arranged between the metal surface and the hole portion. The recessed portion is recessed either upward or downward in the axial direction, overlaps with at least one of the metal surface and the hole portion when viewed in a horizontal direction perpendicular to the central axis.

First claim

What is claimed is:

1. A spindle motor for use in a disk drive apparatus including a cover member to be attached to the spindle motor, the spindle motor comprising:
a rotor portion arranged to rotate about a central axis extending in a vertical direction, and including a rotor magnet;
a bearing portion arranged to support the rotor portion such that the rotor portion is rotatable about the central axis;
a stator portion arranged opposite to the rotor magnet; and
a base portion molded by casting, and arranged to contain the rotor portion, the bearing portion, and the stator portion; wherein
the base portion includes a plate portion arranged to extend radially with respect to the central axis, and a wall portion arranged to extend in an axial direction from a radially outer edge of the plate portion;
the wall portion includes a hole portion in which an attaching member to attach the cover member to the spindle motor is arranged, and is arranged to support at least a portion of the cover member;
an inside surface of the base portion includes a metal surface subjected to a cutting process;
the base portion includes a recessed portion arranged between the metal surface and the hole portion; and
the recessed portion is recessed either upward or downward in the axial direction, and is arranged to overlap with at least one of the metal surface and the hole portion when viewed in a horizontal direction perpendicular to the central axis.

2. The spindle motor according to claim 1 , wherein the recessed portion is arranged to overlap with both the metal surface and the hole portion when viewed in the horizontal direction.

3. The spindle motor according to claim 2 , wherein the hole portion and the metal surface are arranged to overlap with each other when viewed in the horizontal direction.

4. The spindle motor according to claim 1 , wherein
when a straight line which is tangent to an edge portion of the metal surface on one side and to an edge portion of the hole portion on the one side in a plan view is defined as a first straight line, and a straight line which is tangent to the edge portion of the metal surface on an opposite side and to the edge portion of the hole portion on the opposite side in the plan view is defined as a second straight line;
an area surrounded by the edge portion of the metal surface, the edge portion of the hole portion, the first straight line, and the second straight line is arranged to overlap with at least a portion of the recessed portion in the plan view.

5. The spindle motor according to claim 4 , wherein each of the first and second straight lines is arranged to overlap with the recessed portion in the plan view.

6. The spindle motor according to claim 1 , wherein a surface of the recessed portion includes a chill layer.

7. The spindle motor according to claim 6 , wherein the surface of the recessed portion includes a coating film.

8. The spindle motor according to claim 1 , wherein the recessed portion is defined in the wall portion.

9. The spindle motor according to claim 8 , wherein
the recessed portion is recessed upward from a lower surface of the base portion;
an upper end portion of the recessed portion is arranged in the wall portion;
the wall portion includes an inner wall portion arranged between an inside surface of the wall portion and the recessed portion in a plan view, and an outer wall portion arranged between the recessed portion and an outside surface of the wall portion in the plan view;
the hole portion is defined in the outer wall portion; and
the inner wall portion is arranged to have a thickness smaller than a thickness of the outer wall portion.

10. The spindle motor according to claim 9 , wherein
the upper end portion of the recessed portion is arranged in the wall portion, and is arranged at a level higher than that of a lower end portion of the hole portion.

11. The spindle motor according to claim 10 , wherein
when a straight line which is tangent to an edge portion of the metal surface on one side and to an edge portion of the hole portion on the one side in a plan view is defined as a first straight line, and a straight line which is tangent to the edge portion of the metal surface on an opposite side and to the edge portion of the hole portion on the opposite side in the plan view is defined as a second straight line;
an area surrounded by the edge portion of the metal surface, the edge portion of the hole portion, the first straight line, and the second straight line is arranged to overlap with at least a portion of the recessed portion in the plan view.

12. The spindle motor according to claim 11 , wherein each of the first and second straight lines is arranged to overlap with the recessed portion in the plan view.

13. The spindle motor according to claim 1 , wherein an inside of the hole portion includes a screw thread.

14. The spindle motor according to claim 1 , wherein the hole portion is a hole in which a pin to position the cover member is arranged.

15. A disk drive apparatus comprising:
the spindle motor of claim 1 ;
a disk supported by the spindle motor;
an access portion arranged to perform at least one of reading and writing of information from or to the disk;
a cover member attached to the base portion of the spindle motor; and
an attaching member arranged to attach the cover member to the base portion of the spindle motor; wherein
the cover member includes a sealing portion arranged to be in contact with an upper surface of the wall portion; and
the sealing portion is arranged radially inward of the hole portion.

16. The disk drive apparatus according to claim 15 , wherein the sealing portion is arranged to axially overlap with the recessed portion.

Assignees

• Nidec Corp

Inventors

• Nakamura Akiyoshi
• Hirasawa Toshihiro

Classifications

• G11B19/2009 Primary

  Turntables, hubs and motors for disk drives; Mounting of motors in the drive (means for clamping of disk to turntable G11B17/022 and subgroups) · CPC title

• G11B33/027 Primary

  Covers (G11B33/022 takes precedence; with means for guiding the record carrier G11B17/34) · CPC title

• G11B33/148

  Reducing friction, adhesion, drag · CPC title

• G11B33/025

  Portable cases · CPC title

• G11B25/043

  using rotating discs · CPC title