Stator for electric rotating machine
A stator includes a stator coil that is formed of electric conductor segments welded to one another. Each of the electric conductor segments includes at least one joining portion that is welded to another one of the electric conductor segments. The joining portion includes a first part and a second part that are arranged in a longitudinal direction of the electric wire segment. The second part includes a distal end of the electric wire segment, and the first part is on the opposite side to the distal end. The first part extends with its cross-sectional area perpendicular to the longitudinal direction continuously decreasing at a first predetermined rate toward the second part. The second part extends with its cross-sectional area perpendicular to the longitudinal direction continuously decreasing at a second predetermined rate toward the distal end. The second predetermined rate is less than the first predetermined rate.
1. A stator for an electric rotating machine, the stator comprising a stator core and a stator coil, wherein
the stator coil is formed of a plurality of electric conductor segments that are mounted on the stator core and welded to one another,
each of the electric conductor segments includes at least one joining portion that is welded to another one of the electric conductor segments,
the joining portion includes a first part and a second part that are arranged in a longitudinal direction of the electric wire segment,
the second part includes a distal end of the electric wire segment, and the first part is on the opposite side to the distal end,
the first part extends with its cross-sectional area perpendicular to the longitudinal direction continuously decreasing at a first predetermined rate toward the second part,
the second part extends with its cross-sectional area perpendicular to the longitudinal direction continuously decreasing at a second predetermined rate toward the distal end, and
the second predetermined rate is less than the first predetermined rate.
2. The stator as set forth in claim 1 , wherein each of the first and second parts of the joining portion has a side surface,
the side surface of the first part extends obliquely with respect to the longitudinal direction of the electric conductor segment at a first oblique angle, and
the side surface of the second part extends obliquely with respect to the longitudinal direction of the electric conductor segment at a second oblique angle that is less than the first oblique angle.
3. The stator as set forth in claim 2 , wherein the second side surfaces of the first and second parts of the joining portion are smoothly connected to each other via a curved surface provided therebetween.
4. The stator as set forth in claim 1 , wherein for each of the electric conductor segments, there is provided an insulating coat that partially covers the electric conductor segment so as not to cover the joining portion.
5. The stator as set forth in claim 4 , wherein each of the electric conductor segments includes a plurality of intersecting parts each of which is located outside of the stator core and intersects with another one of the electric conductor segments, and
all the intersecting parts are completely covered with the insulating coat.
6. The stator as set forth in claim 1 , wherein each of the electric conductor segments is made of a copper wire having a substantially rectangular cross section.
7. The stator as set forth in claim 1 , wherein each of the electric conductor segments has a substantially U-shape,
for each of the electric conductor segments, the joining portion is formed at one end of the electric conductor segment, and
all the joining portions of the electric conductor segments are arranged on the same axial side of the stator core.