Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1998-03-25
2001-05-08
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S201000, C310S202000, C310S203000, C310S206000, C310S216006, C310S198000, C310S179000, C029S596000
Reexamination Certificate
active
06229241
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure and a manufacturing method of a rotary type motor in which coils are incorporated in the slots of a stator.
Further, the present invention relates to a motor which has coils of a plurality of phases for generating a rotating magnetic field at a stator and a manufacturing method for the stator and, more particularly, to a highly efficient compact lightweight motor ideally suited for an electric vehicle and a manufacturing method for a stator thereof.
2. Description of the Related Art
As shown in
FIG. 2
, a stator
2
a
of a rotary type motor such as a DC motor has a structure in which a plurality of coils
2
c
composed of wound copper wire or the like installed on a multilayer iron core
2
b
constructed by iron sheets.
FIG. 3
shows the top view of a multilayer iron core
3
a
before the coils are installed. A typical multilayer iron core is made as follows: a silicon steel plate having a thickness of 0.3 mm to 0.5 mm is cut by electric discharge machining, pressing, etc., and shaped into an annular component provided with slots, namely, the grooves in which the coils are inserted, formed In the inner periphery thereof. Multiple of the annular components are stacked, and the inner diameters and slots thereof are aligned, then bonded by welding or caulking. Slots
3
b
through
3
m
are provided at equal intervals in the inner periphery of the multilayer iron core
3
a;
coils
4
a
as shown in
FIG. 4
composed of wound and formed copper wires are installed in these slots. There is an alternative available method in which wire is directly wound in the slots to form the coils. The coil
4
a
shown in
FIG. 4
has inserts
4
b
and
4
c
which are fitted in the slots of a stator, and coil ends
4
d
and
4
e
which are disposed at the top and bottom of the stator. Such a coil comes roughly in two types. In one type, a thick wire having a diameter of about 1.2 mm to about 3 mm is wound and the inserts are pressed to have rectangular shapes and aligned. In the other type, a thin wire having a diameter of 1.2 mm or less is wound, and the wires of the inserts are bundled and shaped. In either type, the coils are shaped before they are self-fused or the wires are bonded to each other with an adhesive agent. These coils are incorporated in the stator to make up a motor stator. Incidentally, the term “self-fusing” is a method in which a nylon or epoxy type resin is coated on the surfaces of wires in advance and it is melted by heating with current or hot air or by heating in a furnace so as to bond the wires to each other.
FIG. 5
shows how the coil
4
a
is inserted in the stator
5
a.
The two inserts
4
b
and
4
c
are fitted in two slots
5
b
and
5
c
in the inner periphery of the stator
5
a.
In the same manner, the coils are inserted in the other slots.
Lap winding is one of the structures for installation on the stator.
FIG. 6
illustrates an example of a motor stator
6
a
which employs the lap winding structure for installing the coils. One coil is mounted on the stator in such a manner that it is spanned over two slots, and the two inserts of each coil are disposed on the inner side and outer side, respectively, in the slots in the radial direction of the stator. For instance, in the case of a coil
6
b,
inserts
6
n
and
6
o
are fitted in slots
6
b
′ and
6
e
′ over two slots
6
c
′ and
6
d
′. One insert
6
n
is disposed on the inner side in the radial direction of the stator in the slot
6
b
′ and the other insert
6
o
is disposed on the outer side in the radial direction of the stator in the slot
6
e
′. Next, inserts
6
p
and
6
q
of an adjoining coil
6
c
are fitted in slots
6
c
′ and
6
f
′ over two slots
6
d
′ and
6
e
′. One insert
6
p
is disposed on the inner side in the radial direction of the stator in the slot
6
c
′ and the other insert
6
q
is disposed on the outer side in the radial direction of the stator in the slot
6
f
′. In the same manner, the adjoining coils
6
d
through
6
m
are installed in slots
6
d
′ through
6
m
′ by lapping them clockwise to complete the winding structure which is evenly shaped in the circumferential direction of the stator
6
a.
This lap winding structure, however, has a major disadvantage: since the inserts of the individual coils
6
b
through
6
m
are disposed on the inner and outer sides of the slots, it is necessary to pull out the inserts of the three coils
6
b
through
6
d
which have been disposed on the inner sides of the slots and to install the inserts of the other three coils
6
k
through
6
m
on the outer sides of the slots. This process for uninstalling the coils requires much time and involves high possibility of damaging the coating of wires, thus posing a big bottleneck in manufacturing motors.
To solve the problem with the coil uninstalling process, a stator
7
a
having a modified lap winding structure shown in
FIG. 7
has been devised. This structure employs three types of coils having different shapes, namely, coils
7
b
through
7
d,
coils
7
k
through
7
m,
and coils
7
e
through
7
j.
First, both inserts of the coils
7
b
through
7
d
are installed so that they are positioned on the outer sides of slots
7
b
′ through
7
g
′, then the coils
7
e
through
7
j
are inserted in slots
7
e
′ through
7
m
′ in order clockwise. Thus, one insert of each of the coils
7
e
through
7
j
is disposed on the inner side in the radial direction of the stator, while the other insert thereof is disposed on the outer side in the radial direction of the stator. The coils
7
b
through
7
d
will have been installed on the outer sides of slots
7
k
′ through
7
d
′ before inserting last three coils
7
k
through
7
m;
hence, both inserts of each of the coils
7
k
through
7
m
are respectively installed on the inner sides of the slots
7
k
′ through
7
d
′. As described above, this structure allows the coils to be inserted in the stator in succession without the need for the coil uninstalling process. The structure requires, however, that the three different types of coils, namely,
7
b
through
7
d,
7
e
through
7
j,
and
7
k
through
7
m
having different shapes, are manufactured separately, and the inserting sequence based on the type of coils is observed. Further, the stator
7
a
develops uneveness in the circumferential direction thereof, leading to uneven revolution of the motor incorporating the stator due to uneven magnetic field.
The foregoing lap winding and modified lap winding use the structure wherein two coil inserts
8
a
and
8
b
are installed in one slot
8
c
and the coils are arranged in the radial direction of the stator as shown in FIG.
8
. In either winding structure, an open-slot stator, which permits easier installation of coils, is normally used. Immediately after a coil has been inserted in a slot or after the coils have been inserted in all slots, paper or a magnetized wedge or wedges
8
d
are placed in an inlet or inlets
8
e
of a slot or slots to secure the coil or coils.
(1)
FIG. 9
illustrates a stator
9
a
having a structure wherein coils
9
b
through
9
j
are inserted clockwise in slots
9
b
′ through
9
m
′ and the last three coils are left uninserted. In the case of the lap winding, the two inserts of each coil are disposed side by side in a slot in the radial direction of the stator as illustrated by
8
a
and
8
b
of FIG.
8
. For this reason, by the time the last three coils, not shown, are inserted in slots
9
k
′,
9
l
′,
9
m
′,
9
b
′,
9
c
′, and
9
d
′, the inserts
9
n,
9
o,
and
9
p
on one side of the three coils
9
b,
9
c
and
9
d
which have been installed first will have already been disposed on the inner sides of the slots
9
b
′,
9
c
′, and
9
d
′, thus preventing the insertion of the coils on the outer sides of the sl
Enomoto Yuji
Hiramatsu Hiromichi
Ishigami Takashi
Ito Motoya
Koizumi Osamu
Hitachi , Ltd.
Lam Thanh
Mattingly, Stanger & Malur
Ramirez Nestor
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