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US 9,318,928 B2Granted
Brushless motor, disk drive apparatus and brushless motor manufacturing method
AssigneeNidec Corporation
InventorsToshikazu Himeno, Hongbing Du, Junichi Hashimoto, Kazuya Enokizono
Life of this patent
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Abstract
A brushless motor includes a plate-shaped armature and a magnet facing either one of a top surface and a bottom surface of the armature. An inner peripheral surface of a base member and an outer peripheral surface of a bearing mechanism contact with each other or face each other in a diametrical direction with an adhesive therebetween in a first fixing part. Further, a rotor yoke and a hub protrusion contact with each other or face each other in a diametrical direction with an adhesive therebetween in a second fixing part. Then, a press-fitting or adhesion is carried out in the other of the first and the second fixing part.
Claims20
A brushless motor, comprising:
- a stationary unit comprising a base member and a bearing mechanism;
- and
- a rotary unit rotatably supported by the bearing mechanism, the rotary unit comprising a hub, a shaft, a rotor yoke and a magnet, the shaft having a central axis,
- wherein the stationary unit comprises:
- a flat armature arranged radially outward of the bearing mechanism to extend in a direction orthogonal to the center axis;
- and
- a base member arranged to support the armature, the base member including a base through-hole extending in the up-down direction,
- wherein the hub is made of a magnetic material, the hub comprising:
- a top plate portion comprising an inner peripheral end, a middle portion and an outer peripheral end, the top plate portion extended from the inner peripheral end through a middle portion to reach an outer peripheral end, the inner peripheral end contacting the shaft, the top plate portion further comprising a first part and a second part, the first part located radially inside the middle portion, the second part located radially outside the middle portion;
- and
- a hub protrusion portion arranged to extend downward from the middle portion of the top plate portion,
- wherein the rotor yoke is made of a magnetic material, the rotor yoke fixed to a radially outer side of the hub protrusion portion such that the rotor yoke is axially opposed to a lower surface of the armature,
- wherein the magnet is fixed to a lower surface of the second part of the hub such that the magnet is axially opposed to an upper surface of the armature while an upper surface of the magnet is entirely covered by the second part of the top plate portion,
- wherein the base member includes an inner circumferential surface defining the base through-hole, the bearing mechanism axially opposed to the first part of the top plate portion, the bearing mechanism including an outer circumferential surface, the inner circumferential surface of the base member arranged to make contact with the outer circumferential surface of the bearing mechanism or to radially oppose the outer circumferential surface of the bearing mechanism across an adhesive agent in a first fixing portion,
- wherein the rotor yoke is arranged to make contact with the hub protrusion portion or to radially oppose the hub protrusion portion across an adhesive agent in a second fixing portion, and
- wherein the brushless motor satisfies a relationship of d1>d2, where the d1 is an axial length between a lower end of a constant diameter surface of the bearing mechanism extending along the first fixing portion or further extending downward from the first fixing portion and an upper end of a constant diameter surface of the base member extending along the first fixing portion or further extending upward from the first fixing portion, and the d2 is an axial length between a lower end of a constant diameter surface of the hub protrusion portion extending along the second fixing portion or further extending downward from the second fixing portion and an upper end of a constant diameter surface of the rotor yoke extending along the second fixing portion or further extending upward from the second fixing portion.
13 more elements
A brushless motor, comprising:
- a stationary unit comprising a base member and a bearing mechanism;
- and
- a rotary unit rotatably supported by the bearing mechanism, the rotary unit comprising a hub, a shaft, a rotor yoke and a magnet, the shaft having a central axis,
- wherein the stationary unit comprises:
- a flat armature arranged radially outward of the bearing mechanism to extend in a direction orthogonal to the center axis;
- and
- a base member arranged to support the armature, the base member including a base through-hole extending in the up-down direction,
- wherein the hub is made of a magnetic material, the hub comprising:
- a top plate portion comprising an inner peripheral end, a middle portion and an outer peripheral end, the top plate portion extended from the inner peripheral end through a middle portion to reach an outer peripheral end, the inner peripheral end contacting the shaft, the top plate portion further comprising a first part and a second part, the first part located radially inside the middle portion, the second part located radially outside the middle portion;
- and
- a hub protrusion portion arranged to extend downward from middle portion of the the top plate portion,
- wherein the rotor yoke is made of a magnetic material, the rotor yoke fixed to a radially outer side of the hub protrusion portion such that the rotor yoke is axially opposed to a lower surface of the armature,
- wherein the magnet is fixed to a lower surface of the second part of the hub such that the magnet is axially opposed to an upper surface of the armature while an upper surface of the magnet is entirely covered by the second part of the top plate portion,
- wherein the base member includes an inner circumferential surface defining the base through-hole, the bearing mechanism axially opposed to the first part of the top plate portion, the bearing mechanism including an outer circumferential surface, the inner circumferential surface of the base member arranged to make contact with the outer circumferential surface of the bearing mechanism or to radially oppose the outer circumferential surface of the bearing mechanism across an adhesive agent in a first fixing portion,
- wherein the rotor yoke is arranged to make contact with the hub protrusion portion or to radially oppose the hub protrusion portion across an adhesive agent in a second fixing portion, and
- wherein the brushless motor satisfies a relationship of d1<d2, where the d1 is an axial length between a lower end of a constant diameter surface of the bearing mechanism extending along the first fixing portion or further extending downward from the first fixing portion and an upper end of a constant diameter surface of the base member extending along the first fixing portion or further extending upward from the first fixing portion, and the d2 is an axial length between a lower end of a constant diameter surface of the hub protrusion portion extending along the second fixing portion or further extending downward from the second fixing portion and an upper end of a constant diameter surface of the rotor yoke extending along the second fixing portion or further extending upward from the second fixing portion.
13 more elements
Dependencies are inferred from the claim text.