Segment coil, method of manufacturing segment coil, and stator including segment coil

1. A segment coil in a stator of a rotating electric machine formed from an annular core and coils of a plurality of phases, segment coils being arranged as aligned in a radial direction in slots of said annular core and coils in adjacent slots being arranged as aligned in a circumferential direction, comprising:

a straight portion accommodated in said slot; and

two coil end portions protruding outward from said slot,

any one coil end portion of said two coil end portions including a first coil piece and a second coil piece, said second coil piece being to be sunk radially inward of an adjacent segment coil, said first coil piece and said second coil piece being formed by inclining a coil at different angles toward said straight portion with a vertex lying between said first coil piece and said second coil piece, and

a recessed step portion provided in said second coil piece, said recessed step portion being formed by setting a first angle formed between said second coil piece in a region in the vicinity of said vertex and a tangential line passing through said vertex to be greater than a second angle formed between said second coil piece except for the region in the vicinity of said vertex and said tangential line, said recessed step portion being not provided in said first coil piece.

2. The segment coil according to claim 1 , wherein

an additional insulating layer is provided in a prescribed region of one of said first and second coil pieces not including said recessed step portion.

3. The segment coil according to claim 2 , wherein

said additional insulating layer is provided in a portion where segment coils belonging to different phases face each other.

4. The segment coil according to claim 2 , wherein

said additional insulating layer is formed on a radially inner surface and/or a radially outer surface of the annular core of the segment coil.

5. The segment coil according to claim 2 , wherein

said any one coil end portion is formed in a mountain shape, and said additional insulating layer is provided in an oblique side portion except for a portion near a peak portion of said mountain shape and portions near opposing mountain-foot portions and/or in a straight portion extending from the slot.

6. The segment coil according to claim 1 , wherein

a semiconductive layer is provided in a prescribed region of a coil piece of said first and second coil pieces not including said recessed step portion, and said semiconductive layer of a segment coil arranged in proximity and belonging to a different phase is in contact at at least one point.

7. The segment coil according to claim 1 , wherein

a colored identification portion is provided on a surface in a prescribed region of said segment coil.

8. The segment coil according to claim 7 , wherein

a coil end portion not including said recessed step portion of the two coil end portions of said segment coil includes a terminal portion for connection of an adjacent segment coil, and a first colored identification portion allowing identification of a terminal portion of a segment coil to be connected is provided in the terminal portion or in a portion near the terminal portion.

9. The segment coil according to claim 7 , comprising a second colored identification portion provided on a surface other than said terminal portion and formed to allow identification of a slot where each segment coil is attached and/or a position of disposition in the slot.

10. The segment coil according to claim 9 , wherein

said second colored identification portion is provided by applying a color paint, bonding a color tape material, or attaching a color tube material to a prescribed region of the segment coil.

11. The segment coil according to claim 9 , wherein

said second colored identification portion serves as an additional insulating layer.

12. A stator formed by arranging the segment coils according to claim 1 , as aligned in slots of an annular core.