Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-03-13
2002-12-31
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S180000, C310S201000, C310S045000
Reexamination Certificate
active
06501206
ABSTRACT:
This application is based on Application No. 2000-276403, filed in Japan on Sep. 12, 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 of, for example, an automotive alternator or the like, and a manufacturing method and a connecting conductor wire for the stator, and a manufacturing method for the connecting conductor wire.
2. Description of the Related Art
Hitherto, a variety of types of electric equipment use diverse types of conductor wires according to individual applications. In some applications, conductor wires are joined together for use.
In such a case, the end portions of conductor wires to be joined are arranged properly, and insulating films formed on the end portions are removed. Then, the stripped end portions are joined, and a new insulating resin is applied to the stripped portions that include the joined portion to complete the joining process of the conductor wires.
Such a joining method, however, has been posing a problem in that the entire distal ends of conductor wires to be joined are melted, requiring high calorie for joining them. There has been another problem in that an increase in heat gain during the joining process causes an increase in the temperature around the end portions of the conductor wires and deteriorates insulating films, with resultant deteriorated insulating properties.
To solve the aforesaid problems, there has been proposed in, for example, Japanese Unexamined Patent Application Publication No. 2000-164043, a conductor wire structure in which the end portions of the conductor wires to be joined are partly cut off to reduce cross-sectional areas of the wires so as to reduce a heat gain during a joining process.
FIG. 19
is a process chart illustrating a conventional process for connecting conductor wires disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2000-164043.
In the conventional process for connecting conductor wires, two conductor wires
100
to be joined are first prepared, and insulating films
116
are removed from the areas around the end portions of the conductor wires
100
(step
1
). Then, end portions
112
of the conductor wires
100
from which the insulating films
116
have been removed are partly cut off as illustrated to form cut portions
114
(step
2
). Substantially half of the round section of each of the end portions
112
of the conductor wires
100
are cut off by forming the cut portion
114
. The cross-sectional area is substantially reduced to half the area connected to the end portion
112
. Then, the two conductor wires
100
are disposed in parallel to each other, with their cut portions
114
facing outward, the end portions
112
being arranged properly. Subsequently, the end portions
112
are joined by, for example, tungsten-inert-gas (TIG) welding (step
3
). Finally, an insulating resin
120
is newly applied to a joined portion
118
and the area from which the insulating films
116
have been removed (step
4
), thus completing the joining process of the two conductor wires
100
.
As described above, in the conventional structure of the conductor wire, the end portion
112
of the conductor wire
100
is partly cut off to reduce the conductor sectional area, so that the insulating film
116
of the conductor wire
100
around the cut portion
114
is inevitably damaged. For this reason, after joining the end portions
112
of the conductor wires
100
, the insulating resin
120
must be applied to a wide area including the joined portion
118
. This has been posing a problem of poor working efficiency and an increase in the volume of the insulating resin
120
, causing the joined portion of the conductor wires to bulge out.
The following will describe a case where the conductor wires having the conventional structure are applied to a stator
121
of an alternator.
As shown in
FIG. 20
, the stator
121
is equipped with a stator iron core
122
and a stator winding
123
composed of conductor wires
124
threaded through slots
122
a
of the stator iron core
122
. In a coil end group
123
a
of the stator winding
123
, joined portions
125
, each being composed of welded end portions of two conductor wires
124
with an insulating resin
120
applied thereto, are aligned in two layers adjacently in one row in the radial direction on an end surface of the stator iron core
122
, being disposed in two rows in the circumferential direction.
Since the end portions of the conductor wires
124
are partly cut off as in the case of the conductor wires
100
described above, the insulating film
116
around the cut-off area is damaged, causing the conductors to be exposed. The joined parts of the end portions of the conductor wires
124
are aligned adjacently in one row in the radial direction on the end surface of the stator iron core
122
, being disposed in two rows in the circumferential direction. Hence, welded portions of the end portions of the conductor wires
124
aligned adjacently in the radial direction are likely to develop short-circuiting. If the insulating resin
120
is applied with a welded portion short-circuited, then the yield of the stator
121
will be reduced.
To prevent the yield from lowering, an inspection for checking the welded portions of the end portions of the conductor wires
124
for a short circuit is performed prior to the application of the insulating resin
120
. A rejected workpiece must be subjected to a step for locating a short-circuited spot, then the short circuit must be corrected by separating the short-circuited welded portions in the radial direction by hand.
It is extremely difficult to locate a short-circuited spot. The step for correcting a short circuit requires the manufacturing line of stators be stopped, and is implemented by hand, leading to significantly reduced productivity and increased cost.
Furthermore, since the insulating resin
120
must be applied to a large sectional area in the vicinity of the cut portion, the joined portion
125
bulges out, adding to a radial dimension and a circumferential dimension. This prevents the stator
121
from being made smaller, and adversely affects the multi-row configuration of the joined portions
125
.
SUMMARY OF THE INVENTION
The present invention has been made with a view toward solving the above problems, and it is an object of the present invention to provide a stator of a dynamo-electric machine and a manufacturing method for the same, and a connecting conductor wire and a manufacturing method for the same in which an end portion of a conductor wire is plastically deformed to minimize the chances of damage to an insulating film and to reduce a cross-sectional area of the end portion thereby to reduce heat gain during a joining process and secure good insulating properties. Moreover, the occurrence of short circuits between joined portions will be structurally prevented so as to obviate the need for manual correction of short circuits that used to be necessary in the conventional art, thus allowing higher productivity and lower cost to be achieved.
To this end, according to one aspect of the present invention, there is provided a stator of a dynamo-electric machine that is equipped with a cylindrical stator iron core having a plurality of slots arranged in a circumferential direction; and a stator winding composed of a plurality of conductor wires installed in the slots, the stator winding being formed by joining end portions of the plurality of conductor wires extending out of different ones of the slots at the end surface of the stator iron core, wherein the conductor wires are formed such that a conductor sectional area of an end portion over a predetermined extent in a lengthwise direction from a distal end thereof is smaller than a conductor sectional area of a main portion, and an insulating film covers the main portion and a part of the end portion in the vicinity of the main portion; and a plurality of the condu
Harada Yoshihiro
Nishitani Shoichiro
Oohashi Atsushi
Mitsubishi Denki & Kabushiki Kaisha
Mullins Burton S.
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