Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-06-13
2003-12-16
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S179000, C310S254100
Reexamination Certificate
active
06664669
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an a.c. generator for a vehicle, which is driven by an internal combustion engine of the vehicle, and a method of producing the a.c. generator.
2. Discussion of Background
FIG. 12
is a cross-sectional view of an example of generally used a.c. generators for vehicles, which is disclosed in Japanese Unexamined Patent Publication JP-A-2000-50553. In the figure, a rotator
1
has a rotating shaft
11
, a pair of field iron cores
12
of a Randle type, engaged with the rotating shaft
11
, and a field winding
13
, fixed to the field iron cores
12
. The rotating shaft
11
is rotated by receiving a driving force by the internal combustion engine of the vehicle through a belt (not shown).
A stator
2
surrounding the rotator
1
has a stator iron core
21
and a group of stator windings
22
, fixed to the stator iron core
21
. An inner peripheral surface of the stator
2
is arranged opposite to an outer peripheral surface of the rotator
1
through a gap. Further, the stator
2
is interposed and held between a front bracket
31
and a rear bracket
32
.
In the next, the stator
2
will be described in detail.
FIG. 13
is a perspective view of a conductor segment, forming the group of the stator windings
22
, wherein a state before building this in the stator iron core
21
is shown. In the figure, the conductor segment
23
is formed by bending a rod-like or plate-like metallic material, e.g. copper, at a bent portion
23
c
so as to be substantially U-like shape. The conductor segment
23
has a conductor
23
a
on an inner layer side, arranged on a side of a slot inner than the bent portion
23
, and a conductor
23
b
on an outer layer side, arranged on a side of a slot outer than the bent portion
23
.
FIG. 14
is a cross-sectional view of a part of the stator iron core
21
.
FIG. 15
is a perspective view of party illustrating a state that the windings are inserted in the stator iron core
21
. The group of the stator windings
22
is formed by inserting two pieces of the conductor segments
23
respectively into each one of the slots
24
of the stator iron core
21
, and by mutually shaping end portions
23
d
of the conductor segments, which were inserted in different slots
24
, as illustrated in FIG.
15
. An insulating coating is respectively formed on surfaces of the conductor segments
23
, and therefore adjacent conductor segments
23
are insulated each other by the insulating coatings. Further, each of the conductor segments
23
is insulated from a corresponding inner wall surface of the slot
24
by a tissue paper
25
.
FIGS. 16 through 18
illustrate a method of producing the stator winding, wherein the tissue paper
25
is omitted. The tissue paper
25
is shaped like a ring sufficient for one slot, and inserted in the slot along an axial direction of the slot
24
. After building the tissue paper
25
in the slot
24
, the conductor segment is inserted in the slots
24
along the axial direction, as arrows A in FIG.
16
. The inserted conductor segment
23
protrudes from the other side surface of the slot
24
at an end portions
23
d
, and the end portions
23
d
are bent in peripheral directions of the stator iron core
21
as arrows B, i.e. twist shaping, to connect another end portion
23
d
of a conductor segment
23
, inserted in a different slot
24
.
However, there are problems in the conventional a.c. generator for the vehicle that a material cost of the tissue paper
25
is required because the conductor segments are insulated from the stator iron core
21
by the tissue paper
25
, the number of steps in manufacturing the a.c. generator is increased, and therefore a cost is increased.
Further, as illustrated in
FIG. 16
, when the conductor segment
23
is inserted in the directions of the arrows A into the slots
24
of the stator iron core
21
and when the conductor segment
23
is bent in the directions of the arrows B at a time of twist-shaping as illustrated in
FIG. 17
, the tissue paper
25
and the insulating coating of the conductor segment
23
are peeled off by a contact between an opening edge of the stator iron core
21
on the end surface
27
and the conductor segment
23
, whereby a resistance to voltage is deteriorated.
Further, as illustrated in
FIG. 17
, when the conductor segment
23
is bent in the directions of the arrows B at the time of twist-shaping, an excessive stress is applied to the end portion
27
of the stator iron core
21
, whereby there are problems that laminated steel plates forming teeth
28
are deformed and shifted in peripheral directions on an inner diameter side of the stator iron core
21
, a magnetic circuit is affected, and therefore an output voltage is decreased.
Further, although the tissue papers
25
are interposed between the stator iron core
21
and the conductor segments
23
, gaps still exist between inner wall surfaces of the slots
24
and the tissue papers
25
. Therefore, there is a problem that a quality of the a.c. generator for vehicle is deteriorated by a shift of the conductor segment
23
at a time of inserting this, insufficient insulation caused by intrusion of moisture into the gaps, and deterioration of heat conductivity (cooling capability) between the conductor segments
23
as electric heating elements and the stator iron core
21
.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide an a.c. generator for a vehicle which has high insulating and cooling capabilities of a stator, is easily manufactured, has a high quality, and is produced at a low cost, and also to provide a method of manufacturing the a.c. generator.
According to a first aspect of the present invention, there is provided an a.c. generator for a vehicle comprising: a rotator; a stator iron core arranged opposite to an outer periphery of the rotator and having a plurality of slots; and a stator including a plurality of conductor segments, which are accommodated in the slots to form a stator winding, wherein the stator iron core is insulated from the conductor segments by coating at least an end surface of the stator iron core and an inner wall surfaces of the slots with an insulating resin.
According to a second aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the insulative resin is formed around opening edges of the slots on sides of the end surfaces of the stator iron core so as to be in a rounded shape or a chamfered shape.
According to a third advantage of the present invention, there is provided the a.c. generator for the vehicle, wherein the stator iron core is formed to be in a rounded shape or a chamfered shape around opening edges of the slots on sides of the end surfaces of the iron core.
According to a fourth aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the insulative resin is made thicker at around opening edges of the slots on sides of the end surfaces of the stator iron core than at center portions of the slots in their axial directions.
According to a fifth aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the conductor segments have a substantially rectangular cross-sectional shape.
According to a sixth aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the end surfaces of the stator iron core are shaped to be uneven.
According to a seventh aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the inner wall surfaces of the slots are shaped to be uneven.
According to an eighth aspect of the present invention, there is provided the a.c. generator for the vehicle, wherein the insulative resin has a breaking strength sufficient to withstand breakage, caused at a time of inserting the conductor segments into the slots.
According to a ninth aspect of the present invention, there i
Asao Yoshihito
Oohashi Atsushi
Mitsubishi Denki & Kabushiki Kaisha
Mullins Burton
Sughrue & Mion, PLLC
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