Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-03-12
2002-12-24
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S179000, C310S180000, C310S201000, C310S045000
Reexamination Certificate
active
06498414
ABSTRACT:
This application is based on Application No. 2000-259299, filed in Japan on Aug. 29, 2000, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stator of a dynamo-electric machine and, more particularly, to a structure of a stator of an alternator driven by an internal combustion engine, such as a structure of a stator of an automotive alternator that can be mounted on a passenger car, a truck, or the like.
2. Description of the Related Art
FIG. 15
is a schematic perspective view showing conductor segments which are constituents of a stator winding in a stator of a conventional automotive alternator disclosed in, for example, Japanese Unexamined Patent Publication No. 11-164506.
FIG. 16
is a simplified view showing coil-end groups in the conventional stator of the automotive alternator shown in
FIG. 15
, and
FIG. 17
is a simplified view illustrating the layout of joint portions of the coil-end group in the conventional stator of the automotive alternator shown in FIG.
15
.
Referring to
FIG. 15
, a first conductor segment
331
is formed by bending a copper constituent that is covered with an insulating film and has a rectangular cross section. The first conductor segment
331
is substantially formed into a U shape by connecting a pair of straight portions
331
a
and
331
b
at a turn portion
331
c.
A second conductor segment
332
is formed by bending a copper constituent that is covered with an insulating film and has a rectangular cross section. The second conductor segment
332
is also substantially formed into a U shape by connecting a pair of straight portions
332
a
and
332
b
at a turn portion
332
c.
In a conventional stator
100
, a pair of the first conductor segment
331
and the second conductor segment
332
constructed as set forth above is inserted into a pair of slots of a stator iron core
101
from one end of a the stator iron core, the slots being spaced apart from each other by one magnetic pole pitch. Four straight portions
331
a,
332
a,
332
b,
and
331
b
are accommodated in each slot such that they are aligned in one row in the radial direction or the direction of slot depth. For the convenience of explanation, the positions of the straight portions aligned in each slot will be referred to as a first address, a second address, a third address, and a fourth address, the first address indicating the innermost position. As shown in
FIG. 15
, an end portion
331
d
of the first conductor segment
331
extending out from the first address of one slot to the other end of the stator iron core
101
is joined by welding to, for example, an end portion
332
d
of the second conductor segment
332
extending out from the second address of another slot to the other end of the stator iron core
101
, the slot being spaced apart clockwise from the above slot by one magnetic pole pitch. Furthermore, an end portion
332
e
of the second conductor segment
332
extending out from the third address of one slot to the other end of the stator iron core
101
is joined by welding to, for example, an end portion
331
e
of the first conductor segment
331
extending out from the fourth address of another slot to the other end of the stator iron core
101
, the slot being spaced apart clockwise from the above slot by one magnetic pole pitch. Thus, a lap-wound winding having four turns for each phase is formed. Furthermore, the lap-wound windings for three phases are ac-connected to make up a stator winding
102
.
In the stator
100
configured as described above, a coil-end group
102
a
of the stator winding
102
at one end of the stator iron core
101
is constituted by the first conductor segments
331
and the second conductor segments
332
arranged in two layers in the circumferential direction such that the turn portions
331
c
of the first conductor segments
331
surround the turn portions
332
c
of the second conductor segments
332
in an axial direction, as shown in FIG.
16
and
FIG. 17. A
coil-end group
102
b
of the stator winding
102
at the other end of the stator iron core is constituted by a joint portion
334
a
of the end portions
331
d
and
332
d
and a joint portion
334
b
of the end portions
331
e
and
332
e
arranged adjacently in two layers in one row in the radial direction, being arrayed in two rows in the circumferential direction, the joint portions
334
a
and
334
b
being flush in the axial direction.
However, in the coil-end group
102
b
of the stator winding
102
of the conventional stator
100
, the joint portions
334
a
and
334
b
are aligned in two layers adjacently in a single row in the radial direction, being arranged in two rows in the circumferential direction, and the heights of the joint portions
334
a
and
334
b
being the same in the axial direction. Hence, the radial interval between the joint portions
334
a
and
334
b
from which the insulating film has been lost due to welding is small, presenting a problem of proneness to short-circuiting. There has been another problem in that the joint portions
334
a
and
334
b
that are adjacent to each other in the radial direction and have the same height in the axial direction make it difficult to weld them, adversely affecting welding efficiency.
To solve the above problems, an improvement in which the joint portions
334
a
and
334
b
are arranged by shifting them in the circumferential direction has been proposed in, for example, Japanese Unexamined Patent Publication No. 2000-166150.
FIG. 18
is a schematic perspective view showing conductor segments of a stator winding in a stator of an improved conventional automotive alternator disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-166150.
FIG. 19
is a development partial side view, observed from an inner diameter side, of the stator of the conventional automotive alternator shown in FIG.
18
.
FIG. 20
is a simplified view illustrating the layout of joint portions in a coil-end group in the stator of the conventional automotive alternator shown in FIG.
18
.
In an improved stator
100
A, when welding end portions
331
d,
332
d,
331
e,
and
332
e,
the end portions of a first conductor segment
331
and a second conductor segment
332
extending out to the other end of a stator iron core
101
are tilted at different angles so as to cause joint portions
334
a
and
334
b
to be shifted in a circumferential direction by “w,” as shown in FIG.
18
and FIG.
19
.
With this arrangement, a coil-end group
102
b
of the stator winding
102
at the other end of the stator iron core
101
is configured such that the joint portions
334
a
and
334
b
have the same axial height, and are shifted by “w” in the circumferential direction and arranged in two rows in the circumferential direction, as shown in FIG.
20
.
The stator
100
A shares the same construction as that of the stator
100
except that the joint portions
334
a
and
334
b
are shifted by “w” in the circumferential direction.
Another conventional stator structure employing first, second, and third conductor segments
331
,
332
, and
333
has been disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-166150. In a stator
100
B shown in
FIGS. 21 and 22
, a coil-end group
102
a
of a stator winding
102
is constituted by turn portions
331
c,
332
c,
and
333
c
arranged in the circumferential direction in three layers in the axial direction. A coil-end group
101
b
is constituted by joint portions
334
a,
334
b,
and
334
c
which share the same axial height and are arranged in three rows in the circumferential direction so that they are shifted in the circumferential direction by “w”.
In the stators
100
A and
100
B constructed as set forth above, the intervals between the joint portions are longer since the joint portions are shifted in the circumferential direction. This arrangement is expected to suppress the occurrence of short-circuiting between the joint portions that have lo
Mitsubishi Denki & Kabushiki Kaisha
Mullins Burton S.
Sughrue & Mion, PLLC
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