Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-04-17
2003-03-11
Bryant, David P. (Department: 3726)
Metal working
Method of mechanical manufacture
Electrical device making
C029S605000, C029S732000, C242S432000
Reexamination Certificate
active
06530140
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing an AC generator's stator for a vehicle such as a passenger car or a truck.
PRIOR ART
Since the AC generator for a vehicle has been required to be more powerful, the resistance of the stator winding is required to be lower and lower, thereby reducing the length of the magnet wire.
It is well known that a plurality of U-shaped conductor segments are respectively inserted into slots of a stator core in the same direction and are connected with each other to form a stator winding, thereby increasing the output power of a vehicular AC generator, as disclosed in International Publication Number WO 92/06527 (1992). Because U-shaped conductor-segments can be disposed very regularly in this structure, the slot-space factor and the output power thereof can be increased.
Before turn portions of conductor segments are twisted in a manufacturing process of the above conventional structure, an annular holder
310
holds the turn portions
301
a
,
302
a
,
303
a
of the conductor segments
301
,
302
,
303
as shown in
FIG. 16
of the present application. Straight portions
301
b
,
302
b
,
303
b
are inserted into twisting tools
311
,
312
, which are twisted relative to the annular holder
310
in directions opposite from each other by an angle of T/
2
(T is a pole-pitch angle). As a result, the straight portions
301
b
,
302
b
,
303
b
of the segments
301
,
302
,
303
are twisted at T/
2
as shown in FIG.
17
.
Because the annular holder
310
holds entire arc portions of the turn portions
301
a
,
302
a
,
303
a
of the segments
301
,
302
,
303
, the coil ends becomes longer than coil ends formed without using the annular holder
310
. That is, the wire length becomes longer.
In this conventional method, when the segments
301
,
302
,
303
are inserted into the slots, the segments
301
,
302
,
303
are held by the annular holder
310
at the turn portions
301
a
,
302
a
,
303
a
. The straight portions
301
b
,
302
b
,
303
b
are inserted into the slots with only the turn portions
301
a
,
302
a
,
303
a
being held.
In this method, the segments
301
,
302
,
303
are held only at the turn-portions
301
a
,
302
a
,
303
a
disposed on the end of the stator core opposite the end from which the segments are inserted into the slots. Therefore, the straight portions
301
b
,
302
b
,
303
b
can not be positioned accurately, and the segments
301
,
302
303
may collide with the slot-inner-walls to be damaged when the conductor segments are inserted into the slots. If the number of slots increases, the distance between the slots decreases, and higher accuracy is necessary to the method. However, it is difficult for this method not provide such high accuracy.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is made to solve the above problems and to provide a method and an apparatus for manufacturing a stator that improves the accuracy in inserting the segments into the slots.
The present invention is to provide a method and an apparatus for manufacturing a stator that reduces damages to the segments, and which form the short coil ends.
The present invention is also to provide a method and an apparatus for manufacturing a stator that has short coil ends.
To achieve the above objects, there is a feature characterized by including a conductor holder (
21
,
22
) holding conductor segments (
3
,
31
,
32
) and an axial-moving mechanism (
214
) which moves the conductor holder (
21
,
22
) in the axial direction relative to a stator core (
1
). The conductor holder includes a guide guiding straight portions (
31
b
,
31
c
,
32
b
,
32
c
) of the conductor segments (
3
,
31
,
32
) inserted into the slots (
2
) in an axial direction.
Because the guide guides the straight portions of the conductor segments (
3
,
31
,
32
) inserted into the slots (
2
), the positioning-accuracy can be improved compared with a method in which only one end of the turn-portion is held. As a result, the conductor segments (
3
,
31
,
32
) are prevented from being damaged by their collision with the slot-inner-walls. The guide of the conductor holder (
21
,
22
) is a member guiding straight portions (
31
b
,
31
c
,
32
b
,
32
c
) of the conductor segments (
3
,
31
,
32
) into the prescribed positions. The guide can be integrated into a conductor holder which holds and moves the straight portions (
31
b
,
31
c
,
32
b
,
32
c
) of the conductor segments (
3
,
31
,
32
), or into a guide member which guides the conductor segments (
3
,
31
,
32
) in a inserting step.
It is preferable, to improve positioning-accuracy, that the conductor holder (
21
,
22
) guides the straight portions (
31
b
,
31
c
,
32
b
,
32
c
) at portions adjacent to an end of the stator core (
1
)
The conductor holder (
21
,
22
) includes a circumferential guide (
211
d
,
211
e
) which guides opposite sides of the straight portions (
31
b
,
31
c
,
32
b
,
32
c
) in the circumferential direction of the stator core (
1
).
Because the circumferential guide restricts the circumferential movement of the conductor segments (
3
,
31
,
32
), the conductor segments (
3
,
31
,
32
) are prevented from colliding with inner-walls of the slots (
2
).
The conductor holder (
21
,
22
) comprises a radial guide (
211
c
,
221
) which guides opposite sides of the straight portions (
31
b
,
31
c
,
32
b
;
32
c
) in the radial direction of the stator core (
1
).
Because the guide restricts radial movement of the conductor segments (
3
,
31
,
32
), the conductor segments (
3
,
31
,
32
) can be prevented from colliding with the radially inner-walls of the slots (
2
).
The circumferential guide (
211
d
,
211
e
) and radial guides (
211
c
,
221
) move in the radial direction of the stator core (
1
).
The conductor holder (
21
,
22
) holds the plural conductor segments (
3
,
31
,
32
) at the same time.
The circumferential-directional guide portions (
211
d
,
211
e
) and the radial-directional guide portions (
211
a
,
221
c
) can be moved in the radial direction.
Because a plurality of conductor segments (
3
,
31
,
32
) are held and inserted simultaneously, manufacturing efficiency can be improved.
A presser (
16
) can be added to press-fits the conductor segments (
3
,
31
,
32
) into the stator core (
1
) in the axial direction of the stator core (
1
).
Therefore, the conductor segments (
3
,
31
,
32
) can be inserted into the slots and position the same as desired.
The conductor segments (
3
,
31
,
32
) are preferably U-shaped, and the presser (
16
) comprises a circumferential supporting portions (
16
a
) restricting turn portions (
31
a
,
32
a
) of the conductor segments (
3
,
31
,
32
) to move in the circumferential direction of the stator core (
1
).
In this structure, because the circumferential supporting portions (
16
a
) sandwiches the turn portions (
31
a
,
32
a
) at the middle between opposite circumferential sides, the circumferential movement of conductor segments (
3
,
31
,
32
) can be restricted. The circumferential supporting portions (
16
a
) prevents the circumferential movement of the conductor segments (
3
,
31
,
32
) so that the conductor segments (
3
,
31
,
32
) can be prevented from colliding with the circumferential inner-walls of the slots (
2
) when the same are inserted into the slots (
2
).
The circumferential holder (
16
a
) has a projection disposed on a surface of the presser (
16
) in contact with the turn portions (
31
a
,
32
a
) of the conductor segments (
3
,
31
,
32
).
An axial holder (
24
) is further included at an end of the stator core opposite the presser (
16
) to hold edge portions (
31
d
,
31
e
,
32
d
,
32
e
) of the conductor segments (
3
,
31
,
32
) in an axial direction when the presser (
16
) presses down the conductor segments (
3
,
31
,
32
).
When the presser (
16
,
23
) presses down the conductor segments (
3
,
31
,
32
), both the turn portions (
31
a
,
31
b
) and the edge portions (
31
d
,
31
e
,
32
d
,
32
e
)
Kamakura Youichi
Maeda Kazutaka
Sugiyama Masaru
Suko Nobuo
Takahashi Makoto
Bryant David P.
Denso Corporation
Harness Dickey & Pierce PLC
Kenny Stephen
LandOfFree
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