Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-11-27
2004-08-17
Mullins, Burton S. (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S216006
Reexamination Certificate
active
06777850
ABSTRACT:
This application is based on Application No. 2001-093425, filed in Japan on Mar. 28, 2001, 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 and a stator core used in a dynamoelectric machine such as an automotive alternator and a method for manufacture thereof, and particularly to a stator core construction.
2. Description of the Related Art
In a dynamoelectric machine such as an automotive alternator, reductions in size and increases in output are in demand. Various proposals have been made which attempt to achieve reductions in size and increases in output by raising the space factor of electrical conductors housed in magnetic circuits of stators, and in addition, by aligning in rows and increasing the density of coil ends of stator windings (crossover portions of a stator winding which are constructed at end surfaces of a stator core). Stator cores are normally prepared by laminating thin magnetic plates in the order of 0.3 to 1.0 mm in order to suppress core loss.
FIG. 16
is a perspective showing a conventional stator for an automotive alternator,
FIG. 17
is a diagram explaining a method for manufacturing a stator winding used in the conventional stator for an automotive alternator,
FIG. 18
is a perspective showing a laminated body constituting a stator core used in the conventional stator for an automotive alternator,
FIG. 19
is a perspective showing the stator core used in the conventional stator for an automotive alternator, and
FIGS. 20A
to
20
D are process cross sections explaining a method for mounting the stator winding to the stator core in the conventional stator for an automotive alternator.
Here, a method for manufacturing the conventional stator will be explained with reference to
FIGS. 17
to
20
D.
First, as shown in
FIG. 17
, an annular winding unit
2
is prepared by winding one strand of a conductor wire
1
coated with an electrical insulator for a predetermined number of winds, and a star-shaped winding unit
3
is prepared by forming the annular winding unit
2
into a star shape in which end portions of adjacent pairs of slot-housed portions
3
a
are alternately linked on an inner circumferential side and an outer circumferential side by linking portions
3
b.
Next, although not shown, thin magnetic plates of predetermined length are prepared by press forming a strip-shaped body composed of a magnetic material. A plurality of plate teeth are formed at a predetermined pitch in a longitudinal direction on the thin magnetic plates. Plate teeth at first and second ends are formed into two matching sections.
A laminated body
5
is prepared as shown in
FIG. 18
by laminating a predetermined number of the thin magnetic plates
4
prepared in this manner such that the plate teeth are superposed, and integrating the laminated thin magnetic plates
4
by welding predetermined positions on an outer surface thereof (the surface on the opposite side from the teeth). Plate-joining weld portions
6
are formed over an entire width region of the laminated body
5
at positions that divide the longitudinal direction of the laminated body
5
into four sections (three positions), for example. Body slots
5
a
are defined by adjacent pairs of body teeth
5
b.
Next, the laminated body
5
is bent into an annular shape with openings of the body slots
5
a
facing an inner circumferential side to obtain a laminated core
7
. First and second ends of the annular laminated core
7
are abutted and an outer circumferential surface of the abutted portion
7
a
is welded to obtain a cylindrical stator core
8
, as shown in
FIG. 19. A
core-joining weld portion
10
is formed over an entire axial region on an outer circumferential surface of the stator core
8
. In this stator core
8
, one core-joining weld portion
10
and three plate-joining weld portions
6
are formed at an even angular pitch on the outer circumferential surface. Core slots
8
a
defined by adjacent pairs of core teeth
8
b
are formed so as to be arranged at an even angular pitch in a circumferential direction with slot grooves lying in an axial direction and slot openings facing an inner circumferential side.
Next, two of the star-shaped winding units
3
are stacked on top of one another such that the slot-housed portions
3
a
of each are mutually offset by three slots in a circumferential direction. The two star-shaped winding units
3
stacked on top of one another in this manner are set in a winding unit inserter as shown in FIG.
20
A. The winding unit inserter is constituted by a core holder
11
, a coil holder
12
, axially-extending blades
13
, a stopper
14
, etc. Here, the stator core
8
is supported by the core holder
11
and the coil holder
12
, the blades
13
being placed on an inner circumferential surface of the stator core
8
so as to open an opening portion of every third core slot
8
a
. The two stacked star-shaped winding units
3
are disposed at a lower end of the stator core
8
such that the slot-housed portions
3
a
thereof are stacked on top of one another in every third core slot
8
a
relative to the axial direction, and linking portions
3
b
on the inner circumferential side are positioned on an inclined surface
14
a
of the stopper
14
.
Next, as the stopper
14
is moved upward in
FIG. 20B
by a driving means (not shown), the linking portions
3
b
on the inner circumferential side slide over the inclined surface
14
a
of the stopper
14
, are shifted to an outer circumferential side, and eventually come into contact with an inner circumferential surface of the blades
13
. As shown in
FIGS. 20B and 20C
, as the stopper
14
moves further upward, the linking portions
3
b
on the inner circumferential side move upward along the inner circumferential surface of the blades
13
, and the slot-housed portions
3
a
move upward and gradually incline. Hence, the slot-housed portions
3
a
are guided by the blades
13
and are gradually housed in the core slots
8
a
from the opening portions of the core slots
8
a
. At this time, the linking portions
3
b
on the outer circumferential side are guided by the coil holder
12
and are gradually shifted upward and to the inner circumferential side. As shown in
FIG. 20D
, as the stopper
14
moves to tip ends of the blades
13
, the linking portions
3
b
on the inner circumferential side are conveyed along the arc-shaped inner circumferential surface of the blades
13
to an upper end of the stator
8
, and the slot-housed portions
3
a
are conveyed completely inside the core slots
8
a
. By this first star-shaped winding unit installation process, the two star-shaped winding units
3
are each installed in every third core slot
8
a.
Next, the stopper
14
is lowered and the blades
13
are rotated circumferentially by one slot. Hence, the blades
13
are placed on the inner circumferential surface of the stator core
8
so as to open an opening portion of every third core slot
8
a
in a group of slots in which the star-shaped winding units
3
are not yet installed. As above, two stacked star-shaped winding units
3
are disposed at the lower end of the stator core
8
such that the slot-housed portions
3
a
thereof are stacked on top of one another in every third core slot
8
a
relative to the axial direction, and the linking portions
3
b
on the inner circumferential side are positioned on the inclined surface
14
a
of the stopper
14
. The stopper
14
is raised and the slot-housed portions
3
a
are conveyed inside the core slots
8
a
in a similar manner to the first star-shaped winding unit installation process above. By this second star-shaped winding unit installation process, the next two star-shaped winding units
3
are each installed into every third core slot
8
a
offset by one slot from those of the first star-shaped winding unit installation process. Similarly, a third star-shaped winding unit installation process is performed to install the remaining two star-shaped winding
Adachi Katsumi
Asao Yoshihito
Harada Yoshihiro
Kuroki Kensaku
Hanh Nguyen
Mitsubishi Denki & Kabushiki Kaisha
Mullins Burton S.
LandOfFree
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