Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-03-17
2001-06-26
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S180000, C310S195000, C310S198000
Reexamination Certificate
active
06252327
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for an outer stator of an inner rotor-type motor.
2. Background Art
In conventional stator structures, a plurality of slots are formed in a circumferential direction so as to be aligned along the axial direction at the inner surface of a stator core formed in the shape of a cylinder. A plurality of stator windings are inserted into one slot.
Inserting the plurality of stator windings in line with the cross-sectional shape of the slots is difficult and gaps occur between the windings and the inner surfaces of the slots. The gaps are due to the insertion of windings having circular cross-sections, which is undesirable. This also limits the space for conductors in a slot. In addition, ohmic loss due to the splitting of the volume of the slots is substantial, and cooling is poor.
There is therefore a need for a small motor in which assembly of the conductor into the slot is straightforward, the space for a conductor within the slot is increased, and ohmic loss is reduced.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the deficiencies of conventional motor stator structures. The present invention includes a motor stator structure in which a plurality of slots oriented in an axial direction are formed at an inner peripheral surface of a cylindrical stator core. Conductors having a substantially conforming cross-sectional shape with the slots are inserted into the slots.
Because the cross-sectional shape of the slots and the conductors substantially conform, the space available for the conductors is increased by up to 100%, ohmic loss is reduced, and cooling is increased.
One conductor may be inserted into each slot of the motor stator structure. When one conductor is inserted into one slot, there are no gaps between windings such as when a plurality of windings are inserted. This arrangement maximizes the capacity of the slots and the space available for the conductor.
The slots of the stator core may be rectangular and extend along a radial direction. A large number of slots can therefore be formed at the inner surface of the stator core, the number of conductors can be increased, and motor performance can therefore be improved.
The conductors can be straight bus bars, and arc-shaped joint plates are arranged along the side surfaces of the stator core. Ends of the joint plates are riveted to the ends of predetermined pairs of bus bars to form a circuit. Because the bus bars are straight, assembly into the slots of the stator core is straightforward.
It is not necessary to bend the ends of a bus bar for coupling because joint plates for coupling prescribed pairs of bus bars are used for this purpose. There is therefore no added difficulty, even when the cross-sectional area of the bus bars is large. Accordingly, substantial space can be maintained for conductors within the slots of the stator core.
The joint plates are arc-shaped and flat, and are arranged on substantially concentric circles at the annular-shaped side surface of the stator core. The stator is therefore compact.
The joint plates and bus bars are riveted together, which makes assembly straightforward and conductivity high.
Long first joint plates and short second joint plates have ends that are bent radially inwards in a deformed C-shape, and a third joint plate has ends bent outwards in the circumferential direction in a deformed C-shape. The plates are arranged on the side surfaces of the stator core.
The entire stator circuit can be constructed by coupling pairs of conductors using the first, second and third types of joint plates. There are therefore few parts and assembly is simplified. The number of overlaid joint plates can be reduced and the stator can be made compact because long first joint plates and short second joint plates can be combined on the same surface.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1
is a front view of the outer stator of a d.c. brushless motor of an embodiment of the present invention;
FIG. 2
is a cross-section taken along line II—O—II of
FIG. 1
;
FIG. 3
is an expanded view of the outer stator;
FIG. 4
is a perspective view of a stator core;
FIG. 5
is a side view of a bus bar;
FIG. 6
is a front view of a bus bar;
FIG. 7
is a side view of a first joint plate;
FIG. 8
is a side view of a second joint plate;
FIG. 9
is a side view of a third joint plate;
FIG. 10
is a cross-sectional view taken along line X—X of FIG.
9
;.
FIG. 11
is a partial perspective view showing the assembly of bus bars and joint plates at the stator core;
FIG. 12
is a perspective view showing part of a coupling structure for an armature circuit;
FIG. 13
is a partial cross-section of a stator of a second embodiment of the present invention; and
FIG. 14
is a partial cross-section of a stator of a third embodiment of the present invention.
REFERENCES:
patent: 2407935 (1946-09-01), Perfetti et al.
patent: 4309634 (1982-01-01), Koroly et al.
patent: 4321497 (1982-03-01), Long
patent: 5587619 (1996-12-01), Yumiyama et al.
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Nguyen Tran
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