Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-07-24
2004-02-10
Vidovich, Gregory (Department: 3726)
Metal working
Method of mechanical manufacture
Electrical device making
C310S179000
Reexamination Certificate
active
06687974
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing an alternator driven by an internal combustion engine mounted to an automotive vehicle such as a passenger car or a truck, for example.
2. Description of the Related Art
FIG. 26
is a perspective of a stator of a conventional automotive alternator such as described in Japanese Patent No. 2927288, for example,
FIG. 27
is a perspective showing a conductor segment used in the stator in
FIG. 26
, and
FIGS. 28 and 29
are perspectives from a front end and a rear end, respectively, of part of the stator in FIG.
26
.
This stator
300
includes: a stator core
301
; a stator winding
302
wound onto the stator core
301
; and insulators
304
mounted inside slots
303
, the insulators
304
insulating the stator winding
302
from the stator core
301
. The stator core
301
is a cylindrical laminated core laminated by stacking thin steel plates which are plate-shaped magnetic members, and has a number of slots
303
extending axially disposed at even pitch circumferentially so as to be open on an inner circumferential side. The stator winding
302
is constructed by joining a number of short conductor segments
305
in a predetermined winding pattern.
The conductor segments
305
are formed into a general U shape from an insulated copper wire material having a rectangular cross section, and are inserted from an axial rear end into pairs of slots
303
six slots apart (a pitch of one magnetic pole). Then, end portions of the conductor segments
305
extending outwards at a front end are joined to each other to constitute the stator winding
302
.
More specifically, in pairs of slots
303
six slots apart, first conductor segments
305
are inserted from the rear end into first positions from an outer circumferential side within first slots
303
and into second positions from the outer circumferential side within second slots
303
, and second conductor segments
305
are inserted from the rear end into third positions from the outer circumferential side within the first slots
303
and into fourth positions from the outer circumferential side within the second slots
303
. Thus, within each slot
303
, four straight portions
305
a
of the conductor segments
305
are arranged to line up in a row in a radial direction.
Then, end portions
305
b
of the conductor segments
305
extending outwards at the front end from the first positions from the outer circumferential side within the first slots
303
and end portions
305
b
of the conductor segments
305
extending outwards at the front end from the second positions from the outer circumferential side within the second slots
303
six slots away in a clockwise direction from the first slots
303
are joined to form an outer layer winding having two turns. In addition, end portions
305
b
of the conductor segments
305
extending outwards at the front end from the third positions from the outer circumferential side within the first slots
303
and end portions
305
b
of the conductor segments
305
extending outwards at the front end from the fourth positions from the outer circumferential side within the second slots
303
six slots away in a clockwise direction from the first slots
303
are joined to form an inner layer winding having two turns.
In addition, the inner layer winding and outer layer winding constituted by the conductor segments
305
inserted into the pairs of slots
303
six slots apart are connected in series to form one phase of the stator winding
302
having four turns.
A total of six phases of the stator winding
302
each having four turns are formed similarly. Then, two sets of three-phase stator winding portions are constructed by connecting three phases each of the stator winding
302
into alternating-current connections.
In the conventional stator
300
constructed in this manner, at the rear end of the stator core
301
, turn portions
305
c
of the pairs of conductor segments
305
inserted into the same pairs of slots
303
are lined up in rows in a radial direction. As a result, the turn portions
305
c
are arranged in two rows circumferentially to constitute a rear-end coil end group.
At the front end of the stator core
301
, on the other hand, joint portions formed by joining the end portions
305
b
of the conductor segments
305
extending outwards at the front end from the first positions from the outer circumferential side within the first slots
303
and the end portions
305
b
of the conductor segments
305
extending outwards at the front end from the second positions from the outer circumferential side within the second slots
303
six slots away, and joint portions formed by joining the end portions
305
b
of the conductor segments
305
extending outwards at the front end from the third positions from the outer circumferential side within the first slots
303
and the end portions
305
b
of the conductor segments
305
extending outwards at the front end from the fourth positions from the outer circumferential side within the second slots
303
six slots away are arranged to line up radially. As a result, joint portions formed by joining end portions
305
b
to each other are arranged in two rows circumferentially to constitute a front-end coil end group.
In the stator
300
of an automotive alternator having the above construction, because the stator winding
302
is constructed by inserting short conductor segments
305
formed in the general U shape into the slots
303
of the stator core
301
from the rear end and joining end portions
305
b
of the conductor segments
305
extending outwards at the front end, the coil end groups are composed of a large number of joint portions, allowing short-circuiting accidents to occur easily because the joint portions easily short-circuit with each other.
A large number of the short conductor segments
305
must be inserted into the stator core
301
and their end portions must be joined by welding, soldering, etc., making operability significantly poor. Furthermore, the amount of each conductor segment
305
which is inserted into the slots
303
must be greater than the length of the stator core
301
, facilitating damage to the insulation and reducing the quality of the finished product. In addition, when joining the end portions, short-circuiting often occurs between the joint portions due to spilt solder or weld melt, making mass-producibility significantly poor.
In contrast to the conventional construction using conductor segments
305
, Japanese Patent Laid-Open No. HEI 8-298756 discloses a stator construction consisting of a number of coil pieces formed by winding a number of straight-angled conductors a number of times into a generally hexagonal shape in advance and inserting the coil pieces into slots in semicircular divided core portions.
In this stator, the coil pieces are inserted into the slots of the semicircular divided core portions in order in a radially outward direction. In other words, first facing side portions of the hexagonal coil pieces are positioned in an inner circumferential layer which is a layer on the inner side of the slots, and second facing side portions are positioned in an outer circumferential layer which is a layer on the outer side a predetermined number of slots away.
In this stator, although the alignment of the coil ends extending outwards from the slots is good, when joining the divided core portions to each other, the first side portions of the coil pieces are already inserted into the slots of a first divided core portion but because it is necessary to perform the operation of inserting the coil pieces into the slots of a second divided core portion at the same time as the operation of connecting the divided core portions, a temporary holding jig or the like must be used to perform a complicated operation, making productivity significantly poor.
Forming the stator core by joining a number of divided core portions has also been troublesome, and forming the radial dimensions, e
Adachi Katsumi
Asao Yoshihito
Morishita Akira
Kenny Stephen
Mitsubishi Denki & Kabushiki Kaisha
Vidovich Gregory
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