Spindle motor having recessed stator coils

• US 5,668,427 A
• Filed: 03/07/1996
• Issued: 09/16/1997
• Est. Priority Date: 07/26/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Morita, Isao
• Primary Examiner(s): LaBalle, Clayton E.
• Application Number:
  US08/612,085
• Time in Patent Office: 558 Days
• Field of Search: 310/42, 310/67 R, 310/216, 310/179, 310/180, 310/254, 29/596
• US Class Current: 310/216.074
• CPC Class Codes: H02K 1/146 consisting of a generally annular yoke with salient poles
• CPC Class Codes: H02K 21/22 with magnets rotating around the armatures, e.g. flywheel magnetos
• CPC Class Codes: H02K 2201/09 Magnetic cores comprising laminations characterised by being fastened by caulking
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A magnet is provided on the inner circumferential surface of a hub rotatable about a central axis C of the motor, and a stator is arranged inside the inner circumferential surface of the hub to oppose the magnet. The stator core of the stator is formed by stacking substantially annular, plate-shaped core forming members, and has an annular portion arranged to be coaxial with the central axis, a plurality of winding portions projecting from the annular portion radially, and pole portions formed on the extending ends of the respective winding portions and opposing the magnet. Each winding portion is squeezed in the stacking direction by plastic formation such that its thickness is smaller than those of the annular portion and pole portion. A coil is wound on each squeezed winding portion.

Claims

1. A spindle motor comprising:

a rotor rotatable about a central axis and having an inner circumferential surface on which a magnet is provided; and

a stator arranged inside the inner circumferential surface to oppose the magnet;

said stator including;

a stator core formed by coaxially stacking a plurality of plate-shaped annular core forming members, each annular core forming member having an annular portion coaxial with the central axis, a winding portion projecting from the annular portion radially with respect to the central axis, and a pole portion formed on the extended end of the respective winding portion and opposing the magnet, said stator core formed by squeezing the entire winding portion of all stacked annular core forming members in a direction of the central axis by plastic formation such that a thickness thereof in the direction of the central axis is smaller than those of the annular portion and each of the pole portions, and

a coil wound entirely within the squeezed winding portion of all stacked members.

2. A spindle motor according to claim 1, wherein each of said winding portions of the stator core is squeezed such that a width thereof in a circumferential direction with respect to the central axis is larger than a width thereof before plastic formation, and such that a length of the stator core in a radial direction with respect to the central axis is held substantially constant during the plastic formation.

3. A spindle motor according to claim 1, wherein said stator core includes annular, plate-shaped first and second core forming members which are stacked coaxially,

the first core forming member has an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, each of the winding forming Portions being squeezed in a direction of plate thickness by plastic formation so as to have a small thickness and such that two end portions thereof in a circumferential direction of the annular portion are bent in an axial direction of the annular portion to form a pair of bent portions,

the second core forming member has an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, and

the first and second core forming members are stacked such that at least one second core forming member is interposed between two first core forming members, and each winding forming portion of the second core forming member is located between the pair of bent portions of a corresponding winding forming portion of the first core forming member.

4. A spindle motor according to claim 1, wherein each of the coil winding portions is squeezed by forces applied thereto in opposite directions such that a squeezed extent decreases from the outermost core forming members in the coil winding portion to a central core forming member therein.

5. A spindle motor according to claim 1, wherein the squeezed portions of the core forming members in each of the winding portions are in tight contact with each other in the direction of the central axis such that there are no air gaps between the corresponding winding portions of the core forming members, and wherein the coil wound on each of the squeezed winding portions is at least partly embedded in the stator core.

6. A spindle motor comprising:

a rotor rotatable about a central axis and having an inner circumferential surface on which a magnet is provided; and

a stator arranged inside the inner circumferential surface to oppose the magnet;

said stator including;

a stator core having an annular portion coaxial with the central axis, a plurality of winding portions projecting from the annular portion radially with respect to the central axis, and pole portions formed on extending ends of the respective winding portions and opposing the magnet, each of the winding portions being squeezed in a direction of the central axis by plastic formation such that a thickness thereof in the direction of the central axis is smaller than those of the annular portion and each of the pole portions, and

a coil wound on each of the squeezed winding portions;

said stator core having annular, plate-shaped first and second core forming members which are stacked alternately and coaxially,

the first core forming member having an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, each of the winding forming portions having a pair of extending portions arranged with a predetermined gap in a circumferential direction of the annular portion,

the second core forming member having an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, each of the winding forming portions of the second core forming member having a width substantially equal to the gap between the pair of extending portions of the first core forming member, and

each of the winding portions of the stator core formed by stacking the first and second core forming members being squeezed in a stacking direction thereof, and each of the winding forming portions of the second core forming member being accommodated between the extending portions of a corresponding winding forming portion of the first core forming member.

7. A spindle motor comprising:

a rotor rotatable about a central axis and having an inner circumferential surface on which a magnet is provided; and

a stator arranged inside the inner circumferential surface to oppose the magnet;

said stator including;

a stator core having an annular portion coaxial with the central axis, a plurality of winding portions projecting from the annular portion radially with respect to the central axis, and pole portions formed on extending ends of the respective winding portions and opposing the magnet, each of the winding portions being squeezed in a direction of the central axis by plastic formation such that a thickness thereof in the direction of the central axis is smaller than those of the annular portion and each of the pole portions, and

a coil wound on each of the squeezed winding portions;

said stator core having annular, plate-shaped first and second core forming members which are stacked coaxially,

the first core forming member having an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, each of the winding forming portions being squeezed in a direction of plate thickness by plastic formation so as to have a small thickness and such that two end portions thereof in a circumferential direction of the annular portion are bent in an axial direction of the annular portion to form a pair of bent portions,

the second core forming member having an annular portion, a plurality of winding forming portions extending from the annular portion radially outward, and pole portion forming portions formed at extending ends of the respective winding forming portions, and

the first and second core forming members being stacked such that at least one second core forming member is interposed between two first core forming members, and each winding forming portion of the second core forming member is located between the pair of bent portions of a corresponding winding forming portion of the first core forming member.