Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-07-17
2003-12-16
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S049540, C029S596000
Reexamination Certificate
active
06664703
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stator for a rotary machine that is driven by an internal combustion engine for the vehicle, for example, and a method for manufacturing the stator.
2. Description of the Related Art
FIG. 13
is a perspective view showing the conventional rotary machine (alternator for vehicle) as disclosed in U.S. Pat. No. 3,078,288, for example. In
FIG. 13
, a rotor
7
of landau type is rotatably attached via a shaft
6
within a case
3
composed of a front bracket
1
and a rear bracket
2
, and a stator
8
is supported on an inner wall face of the case
3
to cover the outer circumferential side of the rotor
7
. The shaft
6
is rotatably supported by the front bracket
1
and the rear bracket
2
. A pulley
4
is secured at one end of this shaft
6
to allow a rotational torque of the engine to be transmitted via a belt (not shown) to the shaft
6
. A slip ring
9
for supplying a current to the rotor
7
is secured to the other end of the shaft
6
, and a pair of brushes
10
are accommodated within a brush holder
11
disposed within the case
3
to slide with the slip ring
9
. A regulator
18
for regulating the magnitude of an AC voltage produced in the stator
8
is connected to a heat sink
17
fitted with a brush holder
11
. A rectifier
12
electrically connected to the stator
8
for rectifying the alternating current produced in the stator
8
to the direct current is mounted within the case
3
.
The rotor
7
comprises a rotor coil
13
for producing a magnetic flux by passing a current, and a pair of pole cores
20
,
21
, provided to cover the rotor coil
13
, for forming the magnetic poles due to the magnetic flux produced by the rotor coil
13
. One pair of pole cores
20
,
21
made of iron have eight pawl-like magnetic poles
22
,
23
projected around the outer circumferential edge at an equiangular pitch in a circumferential direction, and are oppositely secured to the shaft
6
to mate the pawl-like magnetic poles
22
,
23
. Further, the fans
5
are secured to both axial ends of the rotor
7
. Also, the suction holes
1
a
,
2
a
are provided on the axial end faces of the front bracket
1
and the rear bracket
2
, and the exhaust holes
1
b
,
2
b
are provided on both shoulder portions of the front bracket
1
and the rear bracket
2
around the outer circumference, opposed to the radial outside of the coil end groups
16
a
,
16
b
on the front side and the rear side of the stator coil
16
.
The stator
8
comprises a stator iron core
15
composed of a cylindrical laminated iron core with a plurality of axially extending slots
15
a
being formed at a predetermined pitch in the circumferential direction, a polyphase stator coil
16
wound around the stator iron core
15
, and an insulating paper
19
, fitted with in each slot
15
a
, for electrically insulating between the polyphase stator coil
16
and the stator iron core
15
as shown in FIG.
14
. And the polyphase stator coil group
16
has a plurality of coils, each of which is wave wound to take alternately an inner layer and an outer layer in a slot depth direction within the slot
15
a
for every predetermined number of slots, one element wire
30
being folded back outside the slot
15
a
on the end face side of the stator iron core
15
. Herein, the stator iron core
15
to receive two pairs of three-phase stator coils
16
, corresponding to the number of magnetic poles (
16
) for the rotor
7
, so that 96 slots
15
a
are formed at equal interval. For the element wire
30
, a long copper wire material having a rectangular cross section covered with an insulated material is employed, for example.
A method for manufacturing the stator
8
will be specifically described below with reference to
FIGS. 15
to
21
. First of all,
12
long element wires
30
are bent into the shapes of stylized bolts of lightning, (hereinafter described as the shape of a lightning bolt) on the same plane at the same time, as shown in FIG.
15
. Then, they are folded over by a jig in a right angle direction, as indicated by the arrow in
FIG. 16
, and an element wire group
30
A is fabricated as shown in
FIGS. 17A and 17B
. Similarly, an element wire group
30
B having a transition connection and a lead wire are fabricated, as shown in
FIGS. 18A and 18B
. The element wire groups
30
A,
30
B are composed of six pairs of element wires, shifted by one slot pitch, each pair of element wires being arranged in such a way that two element wires
30
formed in this pattern are shifted by a pitch of 6 slots from each other and superposed in a straight part
30
b
, as shown in FIG.
21
. And six end wires of the element wire
30
extend out on either side at either end of the element wire groups
30
A,
30
B. Also, the turn portions
30
a
are aligned at either side portion of the element wire groups
30
A,
30
B.
On the other hand, a certain number of main laminated plates
15
d
made of an SPCC material having a trapezoidal slot
15
a
and the teeth
15
c
formed at a predetermined pitch (an electrical angle of 30°) are laminated, and laser welded at a predetermined position on the outer circumference, thereby producing a laminated iron core
150
of roughly rectangular parallelopiped.
As shown in
FIGS. 20A and 21
, the insulating paper
19
is fitted into the slot
15
a
of an iron core
36
, each straight section of two element wire groups
30
A,
30
B superposed being pushed into each slot
15
a
. Thereby, two element wire groups
30
A,
30
B are attached around the laminated iron core
150
, as shown in FIG.
20
B. At this time, the straight portion
30
b
of the element wire
30
is insulated from the laminated iron core
150
by the insulating paper
19
, and accommodated within the slot
15
a
, four wires being aligned radially. Also, two element wire groups
30
A,
30
B are fitted in superposition around the laminated iron core
150
, as shown in FIG.
21
. Then, the laminated iron core
150
is rounded, the end faces
15
being brought into contact with each other and welded together, whereby the cylindrical stator
8
is produced as shown in FIG.
20
C.
However, in the conventional alternator for the vehicle, since the insulation between the stator coil group
16
and the stator iron core
15
was made by the insulating paper
19
, as described above, there was a problem that the material cost of the insulating paper
19
was taken, a greater number of steps were required, and the costs were increased. Also, there was a further problem that the insulation process such as coating was required as another step on a portion where the iron core portion was exposed, thereby increasing the number of steps.
At a step of forming the stator iron core
15
cylindrically, an excessive stress occurs in the teeth
15
c
of the stator iron core
15
, and a laminated steel plate making up the teeth
15
c
is deformed and shifted circumferentially on the inner diameter side of the stator iron core
15
, disordering a magnetic circuit, resulting in a problem of lower output voltage. And since the insulation between the stator iron core
15
and the stator coil
16
is made by the insulating paper
19
, when the teeth
15
c
is deformed, the insulating paper
19
is ruptured, resulting in a problem of causing a short-circuit with the stator coil
16
.
When the stator coil group
16
is inserted in the slot
15
a
of the stator iron core
15
in a direction of the arrow A, as shown in
FIG. 21
, or when molding the stator iron core cylindrically, as shown in
FIG. 20C
, a reaction force from the stator coil group
16
is exerted. In particular, the stator iron core
15
is molded cylindrically around the neutral axis on the almost central portion of the core pack, whereas each coil group
16
is deformed cylindrically around the neutral axis of each coil group
16
. Therefore, the displacement of the stator iron core
15
and each coil group
16
are different, so that a greater stress is exerted on the teeth
15
c
. Accordingly, a contact occ
Asao Yoshihito
Katayama Hiroki
Oketani Naohiro
Oohashi Atsushi
Takizawa Takushi
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