Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1995-11-21
2001-10-16
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S254100
Reexamination Certificate
active
06304018
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a stator for a motor, and more particularly to an externally-wound stator with improved magnetic transition.
FIG. 6
is a perspective view of a known internally-wound stator core
10
. The internally-wound stator core
10
includes a number of circumferentially spaced-apart pole pieces or teeth
12
which cooperate to defined radially inwardly opening slots
14
which receive coils of wire during a stator winding operation. The stator core
10
can be wound in one of two known techniques, either pre-winding the wire into coils and then inserting the coils radially outwardly into the slots
14
from a central bore
16
of the stator core
10
, or using a needle to thread or wind the wire around the pole pieces
12
from within the slots
14
.
A disadvantage associated with pre-winding a set of coils is that the wires that form the coils are susceptible to damage such as nicking and/or scraping the insulated coating that surrounds or encases the wires, when the coils are inserted around the pole pieces
12
and into the slots
14
from within the central bore
16
. Damaged coil wires can electrically short to other coil wires thus reducing the wire turn count and causing excessive heat generation which may, inter alia, shorten the lifetime of the stator. A disadvantage associated with the needle winding technique is that there are limitations on the number of wire coils (the amount of wire fill) that can be wound around the pole pieces
12
because a certain amount of free space must be reserved in the slot
14
to permit the needle to enter and feed the next wire through the slot
14
.
FIG. 7
is a perspective view of a known externally-wound stator core
20
which eliminates the potential for damaging the coil wires, and eliminates the wire fill limitation associated with the internally-wound stator core
10
. The externally-wound stator core
20
includes a thin circular member
22
defining an inner diameter of the stator core
20
, and a number of circumferentially spaced-apart pole pieces or teeth
24
which are individually joined to the member
22
at the radially innermost edges thereof. The purpose for the member
22
is to structurally retain the pole pieces
24
in a predetermined position so that the stator core
20
can be wound with coils of wire during a stator winding operation. The pole pieces
24
cooperate to defined radially outwardly opening slots
26
for receiving the coils of wire which are wound around the pole pieces
24
in a manner similar to winding an armature. It should be appreciated that a winding operation for an externally-wound stator core is faster and simpler than a winding operation for an internally-wound stator core.
One disadvantage of joining the radially innermost edges of the pole pieces
24
to the member
22
is that the sharp magnetic corners of the pole pieces
24
at the inner diameter of the stator core
20
are eliminated or at least substantially diminished. That is, the member
22
provides a continuous inner circumferential surface which does not permit abrupt changes in reluctance. Sharp magnetic transitions at the radially innermost edges of the pole pieces are required for variable reluctance motor technologies such as switched reluctance motors. However, the member
22
, which is a structural feature of the stator core
20
, provides a magnetic short circuit which may cause a significant amount of flux leakage when a predetermined set of coils is energized. With particular types of magnetic motors, the leakage is an acceptable consequence of the member
22
. However, with variable reluctance motor technologies, the flux leakage is not acceptable as it directly affects torque production.
What is needed therefore is an externally-windable stator core which preserves the sharp magnetic corners of the pole pieces at the inner diameter of the stator core.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a stator lamina having a number of spaced-apart pole pieces, and a member joined to each of the pole pieces at an intermediate portion thereof.
Pursuant to another aspect of the present invention, there is provided a stator core having a number of stator lamina joined together in a direction along a longitudinal axis wherein each of the stator lamina include a number of spaced-apart pole pieces and a member joined to each of the pole pieces at an intermediate portion thereof.
Pursuant to yet another aspect of the present invention, there is provided a motor including a stator core having a plurality of stator lamina joined together in a direction along a longitudinal axis wherein the stator lamina cooperate to define a central bore extending along the longitudinal axis, and wherein each of the stator lamina include a number of spaced-apart pole pieces and a member joined to each of the pole pieces at an intermediate portion thereof. The motor further includes a rotor mounted to rotate within the central bore.
Pursuant to still yet another aspect of the present invention, there is provided a method for winding a stator core including the steps of providing a stator lamina having a number of spaced-apart pole pieces and a member joined to each of the pole pieces at an intermediate portion thereof, providing outwardly opening slots defined by adjacent pole pieces and the member, and winding a wire coil around at least one of the pole pieces so that the wire extends within at least two of the outwardly opening slots.
It is therefore an object of the present invention to provide a new and useful stator lamina which includes a circular member which joins to an intermediate portion of each pole piece.
It is another object of the present invention to provide a new and useful externally-wound stator core which provides abrupt changes in reluctance at the radially inner ends of the pole pieces.
It is a further object of the present invention to provide a new and useful externally-wound stator core which permits higher wire fills than internally-filled stator cores.
It is yet another object of this invention to provide a new and useful externally-wound stator core which prevents the coil wires from being damaged during a winding operation.
It is still another object of the invention to provide a new and useful stator core which can be wound in a quick and easy manner with conventional armature winding equipment.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.
REFERENCES:
patent: Re. 34667 (1994-07-01), Neumann
patent: 2607816 (1952-08-01), Ryder et al.
patent: 2695969 (1954-11-01), Yates
patent: 2711008 (1955-06-01), Smith
patent: 3477125 (1969-11-01), Schwartz
patent: 3489938 (1970-01-01), Nakamura
patent: 3827141 (1974-08-01), Hallerback
patent: 3869629 (1975-03-01), Ogawa et al.
patent: 3914859 (1975-10-01), Pierson
patent: 4025840 (1977-05-01), Brissey et al.
patent: 4080724 (1978-03-01), Gillette
patent: 4466182 (1984-08-01), Lamatsch et al.
patent: 4591766 (1986-05-01), Takaba
patent: 4780635 (1988-10-01), Neumann
patent: 4801832 (1989-01-01), Neumann
patent: 4818905 (1989-04-01), Lender
patent: 4912353 (1990-03-01), Kondo
patent: 4937485 (1990-06-01), Mihalko
patent: 5086245 (1992-02-01), Sieja et al.
patent: 5111096 (1992-05-01), Horst
patent: 5134327 (1992-07-01), Sumi et al.
patent: 5173629 (1992-12-01), Peters
patent: 5173651 (1992-12-01), Buckley et al.
patent: 5306976 (1994-04-01), Beckman
patent: 5313131 (1994-05-01), Hibino et al.
patent: 5349741 (1994-09-01), Neuenschwander
patent: 5382860 (1995-01-01), Fanning et al.
patent: 5502341 (1996-03-01), Sato
patent: 1763506 (1971-11-01), None
patent: 9201325 (1984-08-01), None
Ham Craig A.
Unterborn Ralph J.
Jacox Meckstroth & Jenkins
Nguyen Tran
Valeo Electrical Systems, Inc.
LandOfFree
Externally-wound stator with improved magnetic transition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Externally-wound stator with improved magnetic transition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Externally-wound stator with improved magnetic transition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2602278