Brushless electric machine with stator with cascaded end loops

Abstract

Disclosed herein is a brushless electric machine comprising, a housing, a stationary field coil, a shaft, a bearing, a pole segment, and a stator. The stator including a core having a plurality of core slots that extend between a first and a second end of the stator core. The stator also including a winding with a plurality of phases, each of the phases having at least one conductor having a plurality of substantially straight segments disposed in the core slots. The straight segments are alternately connected at the first and the second ends of the stator core by a plurality of end loop segments. A section of at least one of the conductors including three consecutive end loop segments and two straight segments, is formed from a single continuous conductor, and one of the core slots houses a plurality of the straight segments arranged in at least one radial row.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings wherein like elements are numbered alike in the several Figures:

FIG. 1 depicts a cross section view of a brushless electric machine disclosed herein;

FIG. 2 depicts a cross section view of an alternate brushless electric machine disclosed herein;

FIG. 3 depicts a front plan view of the brushless electric machine illustrated in FIG. 2;

FIG. 4 depicts a front plan view of a rotor only portion of the brushless electric machine illustrated in FIG. 2;

FIG. 5 depicts a perspective view of a stator core disclosed herein;

FIG. 6 depicts a fragmentary top/plan view of a stator core disclosed herein;

FIG. 7 depicts a cross sectional view taken along the line 7-7 in FIG. 6;

FIG. 8 depicts a cross sectional view taken along the line 8-8 in FIG. 6;

FIG. 9 depicts a fragmentary perspective view of an end loop segment of a stator winding disclosed herein;

FIG. 10 depicts a fragmentary perspective view of a layer of end loop segments of a stator winding disclosed herein including the end loop segment of FIG. 5;

FIG. 11 a depicts a perspective view of a plurality of layers of end loop segments of a stator winding disclosed herein including the layer of FIG. 6;

FIG. 11 b depicts a perspective view of a plurality of layers of end loop segments of a stator winding shown in FIG. 11a with a plurality of straight segments and end loop segments disclosed herein;

FIG. 12 depicts a schematic view of a stator core disclosed herein showing the locations of the various winding portions;

FIG. 13 depicts a perspective view of a reversing end loop portion of a stator winding disclosed herein; and

FIG. 14 depicts a cross-sectional view of an alternator disclosed herein.

Claims

1. A brushless vehicle alternator, comprising: a housing;a stationary field coil disposed at the housing;a shaft disposed at the housing;a bearing positioned at the shaft;a pole segment rotatable relative to the housing;a stator surrounding the pole segment, the stator including a core having a plurality of core slots in a surface thereof, the core slots extending between a first end and a second end of the stator core; anda stator winding including a plurality of phases, each of the phases having at least one conductor having a plurality of substantially straight segments disposed in the core slots, the straight segments alternately connected at the first and second ends of the stator core by a plurality of end loop segments, wherein a section of at least one of the conductors including three consecutive end loop segments and two straight segments, is formed from a single continuous conductor, and one of the core slots houses a plurality of the straight segments arranged in at least one radial row.

2. The brushless vehicle alternator of claim 1 wherein the shaft is stationary.

3. The brushless electric machine of claim 2 wherein the shaft is press-fitted to at least one half of the housing.

4. The brushless vehicle alternator of claim 2 further comprising a pulley integral with the pole segment.

5. The brushless vehicle alternator of claim 1 wherein the housing further comprises a plurality of cooling slots.

6. The brushless vehicle alternator of claim 1 wherein at least one of the conductors includes a section having three consecutive straight segments, wherein each of the three consecutive straight segments are disposed in the same radial position.

7. The brushless vehicle alternator of claim 1 wherein at least one of the core slots houses the straight segments housed in only one radial row.

8. A brushless electric machine, comprising: a housing;a stationary field coil disposed at the housing;a shaft disposed at the housing;a bearing positioned at the shaft;a pole segment disposed at the housing;a stator surrounding the pole segment, comprising:a generally cylindrically-shaped stator core having a plurality of circumferentially spaced and axially-extending core slots in a surface thereof, the core slots extending between a first end and a second end of the stator core;a stator winding including a plurality of phases, each of the phases having at least one conductor having a plurality of substantially straight segments disposed in the core slots, the straight segments alternately connected at the first and second ends of the stator core by a plurality of end loop segments; anda section of at least one of the conductors having three consecutive straight segments wherein each of the three consecutive straight segments are disposed in the same radial position.

9. The brushless electric machine of claim 8 wherein at least one of said end loop segments includes a first sloped portion substantially co-radial with said plurality of straight segments and a second sloped portion substantially non-co-radial with said plurality of straight segments, said first and second sloped portions connected by an apex portion thereof.

10. The brushless electric machine of claim 8 wherein at least one of said end loop segments includes a radial adjustment portion.

11. The brushless electric machine of claim 8 wherein the stator winding has at least two layers of conductors and at least one of said layers is shifted a predetermined number of slots from at least one of another said layers.

12. The brushless electric machine of claim 11 wherein said end loop segments of one of said layers extend radially outwardly in a counterclockwise direction on said first end of said stator core and said end loop segments of another one of said layers extend radially outwardly in a clockwise direction on said first end of said stator core.

13. A brushless electric machine, comprising: a housing;a stationary field coil disposed at the housing;a shaft disposed at the housing;a bearing positioned at the shaft;a pole segment rotatable relative to the housing;a stator surrounding the pole segment, comprising:a generally cylindrically-shaped stator core having a plurality of circumferentially spaced and axially-extending core slots in a surface thereof, said core slots extending between a first end and a second end of said stator core; anda stator winding including a section with at least one layer of conductors having a plurality of phases, the section including at least three consecutive end loop segments and at least two consecutive straight segments, each of said phases having a plurality of substantially straight segments disposed in said core slots, said straight segments alternately connected at said first and second ends of said stator core by a plurality of end loop segments, each of three consecutive straight segments being in a substantial same radial distance from a central axis of said stator core, wherein each of said three consecutive end loop segments includes a first sloped portion substantially co-radial with said at least one layer and a second sloped portion substantially non-co-radial with said at least one layer, said first and second sloped portions connected by an apex portion thereof, wherein one of said first sloped portion, said second sloped portion, and said apex portion of each of said end loop segments includes a radial outward adjustment and one of said first sloped portion, said second sloped portion, and said apex portion of each of said end loop segments includes a radial inward adjustment.

14. The brushless electric machine according to claim 13 wherein said outward radial adjustment is a first radial extension at said apex portion and said radial inward adjustment is a second sloping radial extension adjacent one of said straight segments.

15. The brushless electric machine of claim 13 wherein said stator core slots have a substantially rectangular volume.

16. The brushless electric machine of claim 13 wherein said shaft is stationary.

17. The brushless electric machine of claim 13 wherein said shaft is rotatable and the pole segment is attached to the shaft and cantilevered circumferentially about the field coil.

18. The brushless electric machine of claim 13 wherein said straight segments of adjacent phases are disposed in said core slots at an equal pitch around the circumference of said stator core.

19. The brushless electric machine of claim 13 wherein said stator winding includes at least two layers of conductors.

20. The brushless electric machine of claim 13 wherein said section of stator winding including at least three consecutive end loop segments and at least two consecutive straight segments, is formed from a single continuous conductor.