Stator for an alternator and method for the manufacture thereof

• US 20040207283A1
• Filed: 08/27/2002
• Published: 10/21/2004
• Est. Priority Date: 09/17/2001
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hosokawa, Hiroshi, Asao, Yoshihito, Ohnishi, Yukiyoshi, Oohashi, Atsushi, Takizawa, Takushi
• Granted Patent: US 6,960,857 B2
• Time in Patent Office: Days
• US Class Current: 310/207
• CPC Class Codes: H02K 15/0485 manufactured by shaping an annular winding
• CPC Class Codes: H02K 15/067 inserted in parallel to the axis of the slots or inter-polar channels
• CPC Class Codes: H02K 3/12 arranged in slots
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 3/50 Fastening of winding heads, equalising connectors, or connections thereto

Abstract

A stator winding is provided with three distributed winding phase portions each constructed by installing a conductor wire in every third slot. Slot-housed portions of the conductor wires are formed with a rectangular cross section and coil end portions are formed with a circular cross section.

Claims

1. A stator for an alternator, comprising:

a stator core comprising;

an annular core back portion;

tooth portions each projecting radially inward from said core back portion, said tooth portions being disposed at a predetermined pitch in a circumferential direction;

slots defined by adjacent pairs of said tooth portions; and

flange portions projecting to first and second circumferential sides from tip portions of said tooth portions; and

stator winding composed of a plurality of winding phase portions each installed in said stator core in a slot group constituted by a group of said slots disposed at intervals of a predetermined number of slots,

wherein each of said winding phase portions is constructed by installing a conductor wire in a distributed winding in said slot group so as to project from first and second ends of said slots, be distributed on first and second circumferential sides, and enter each of said slots said predetermined number of slots away on said first and second circumferential sides,

each of slot-housed portions of said conductor wire housed in said slots is formed with a flat cross section,

each of coil end portions of said conductor wire linking end portions of said slot-housed portions is formed with a substantially circular cross section, and

said slot-housed portions are housed inside each of said slots in a plurality of layers so as to be arranged in at least a single row in a radial direction.

2. The stator for an alternator according to claim 1 wherein a circumferential width of said slot-housed portions substantially matches a circumferential width of said slots, said slot-housed portions being housed inside said slots so as to be stacked in a radial direction and arranged in a single row.

3. The stator for an alternator according to claim 2 wherein said slot-housed portions are formed such that said circumferential width thereof is larger than a width of an opening of said slots.

4. The stator for an alternator according to claim 1 wherein said slots are formed into a substantially trapezoidal shape tapering radially inward, and said slot-housed portions arranged inside said slots in a radial direction are formed such that the flatness ratio of each slot-housed portion decreases sequentially from an outer radial side to an inner radial side decreases so as to conform said slot-housed portions conform to said substantially trapezoidal shape of said slots.

5. The stator for an alternator according to claim 1 wherein said conductor wire comprises slot-opening passing portions having a flat cross-sectional shape formed at a boundary portion between said slot-housed portions and said coil end portions at a first axial end of said stator core, said slot-opening passing portions being disposed such that longitudinal axes of the cross sections thereof are substantially aligned in a radial direction, and said slot-opening passing portions being formed such that a circumferential width thereof is smaller than a width of an opening of said slots.

6. The stator for an alternator according to claim 1 wherein said slots are formed at a ratio of a plural number per phase per pole.

7. The stator for an alternator according to claim 1 wherein an electrically-insulating resin is applied to a coil end group constituted by said coil end portions of said plurality of winding phase portions.

8. A method for manufacturing a stator for an alternator, said stator comprising:

a stator core comprising;

an annular core back portion;

tooth portions each projecting radially inward from said core back portion, said tooth portions being disposed at a predetermined pitch in a circumferential direction;

slots defined by adjacent pairs of said tooth portions; and

flange portions projecting to first and second circumferential sides from tip portions of said tooth portions; and

stator winding composed of a plurality of distributed winding phase portions each installed in said stator core in a slot group constituted by a group of said slots disposed at intervals of a predetermined number of slots, the method comprising steps of;

preparing said stator core by laminating and integrating a magnetic steel sheet;

preparing an annular winding unit by winding a conductor wire formed with a substantially circular cross section into a ring shape for a predetermined number of winds;

preparing a star-shaped winding unit by bending said annular winding unit into a star-shaped pattern such that straight slot-housed portions are arranged at a predetermined slot pitch in a circumferential direction with a longitudinal direction thereof substantially aligned in a radial direction, end portions of slot-housed portions separated by said predetermined slot pitch in approximately half of said slot-housed portions are alternately linked on an inner circumferential side and an outer circumferential side by first U-shaped coil end portions, end portions of slot-housed portions separated by said predetermined slot pitch in a remainder of said slot-housed portions are alternately linked on an inner circumferential side and an outer circumferential side by second U-shaped coil end portions, and said first coil end portions linking said end portions of approximately half of said slot-housed portions and said second coil end portions linking said end portions of said remainder of said slot-housed portions face each other in a radial direction;

plastically deforming said slot-housed portions of said star-shaped winding unit into a flat cross section;

preparing a cylindrical distributed winding unit by reshaping said star-shaped winding unit such that said slot-housed portions are arranged at said predetermined slot pitch in a circumferential direction with a longitudinal direction thereof parallel to an axial direction; and

mounting said distributed winding unit into said stator core from an axial direction by inserting said slot-housed portions inside said slots while passing a portion of said coil end portions at a first axial end of said distributed winding unit between said flange portions constituting slot openings.

9. The method for manufacturing a stator for an alternator according to claim 8 further comprising the step of bending said coil end portions at said first axial end of said distributed winding unit radially inward before the step of mounting said distributed winding unit into said stator core.

10. The method for manufacturing a stator for an alternator according to claim 8 further comprising the step of forming slot-opening passing portions having a flat cross section by plastically deforming said coil end portions in a vicinity of said slot-housed portions at said first axial end of said distributed winding unit before the step of mounting said distributed winding unit into said stator core.

11. The method for manufacturing a stator for an alternator according to claim 8 wherein all of said slot-housed portions constituting said star-shaped winding unit are press formed simultaneously in the step of plastically deforming said slot-housed portions of said star-shaped winding unit into the flat cross section.

12. The method for manufacturing a stator for an alternator according to claim 8 wherein said slot-housed portions of said star-shaped winding unit constituting said slot-housed portions of said distributed winding unit are mounted into each of said slots so as to align in layers in a radial direction of said slots in the step of mounting said distributed winding unit into said stator core, and said slot-housed portions of said star-shaped winding unit are press formed layer by layer in the step of plastically deforming said slot-housed portions of said star-shaped winding unit into the flat cross section, said slot-housed portions of said star-shaped winding unit in each respective layer being press formed simultaneously.

13. The method for manufacturing a stator for an alternator according to claim 8 wherein a plurality of said distributed winding units constituting said stator winding are stacked concentrically so as to offset said slot-housed portions in each distributed winding unit by a pitch of one slot in a circumferential direction and are mounted into said stator core simultaneously in the step of mounting said distributed winding unit into said stator core.