Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-06-21
2004-04-27
Ponomarenko, Nicholas (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S211000, C310S261100
Reexamination Certificate
active
06727624
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an embedded permanent magnet type induction motor.
A prior art embedded permanent magnet type induction motor (hereinafter referred to as the induction motor) will be described below with reference to
FIGS. 1 and 2
.
FIG. 1
shows a rotor core plate which constitutes the rotor of the induction motor, and
FIG. 2
is a perspective view schematically showing the stator of the induction motor.
Referring to
FIG. 1
, a rotor core plate
40
is a circular thin plate having an aperture
41
in its center. A plurality of rotor slots
42
in which conductors, respectively, are to be embedded are provided in the rotor core plate
40
on the outer peripheral side thereof in the state of being spaced in the circumferential direction at constant intervals. A plurality of holes
43
in which plate-shaped permanent magnets, respectively, are to be embedded are formed in the area between the aperture
41
and the rotor slots
42
. The holes
43
are formed in such a manner that four holes are symmetrically disposed.
After a multiplicity of rotor core plates
40
have been formed into a lamination, conductors (not shown) are embedded into the respective rotor slots
42
by injection molding techniques, and permanent magnets (not shown) are embedded in the respective holes
43
.
It is known that motor performance can be improved by giving a skew angle to the extending direction of each coil embedded in the stator or each of the conductors embedded in the rotor.
FIG. 2
shows a stator in which the skew angle is realized. As shown in
FIG. 2
, a stator
50
is formed of a lamination of a multiplicity of stator core plates
51
. Each of the stator core plates
51
is a circular plate having an aperture
52
in its center. A plurality of stator slots
53
in which coils, respectively, are to be embedded are provided in each of the stator core plates
51
on the inner peripheral side thereof in the state of being spaced in the circumferential direction at constant intervals.
After a multiplicity of stator core plates
51
have been formed into a lamination, coils (not shown) are embedded in the respective stator slots
53
. Particularly when the stator core plates
51
are being laminated one by one, the stator core plates
51
are laminated while the position of each of the stator core plates
51
is being deviated from that of the previous one in the circumferential direction to a slight extent, whereby a skew angle &bgr; is formed.
As described above, the reason why the skew angle &bgr; is realized in the stator
50
is that the stator core plates
51
needs to be laminated while each of the stator core plates
51
is being deviated from the previous one in the circumferential direction to a slight extent. In other words, in the case of the rotor
40
shown in
FIG. 1
, because permanent magnets need to be embedded in the respective holes
43
, the rotor core plates
40
cannot be laminated while each of the rotor core plates
40
is being deviated from the previous one in the circumferential direction.
However, during the work of embedding coils in the respective stator slots
53
after laminating, workability and productivity are inferior because passages each formed by a multiplicity of stator slots
53
arranged consecutively are extended in the inclined direction.
SUMMARY OF THE INVENTION
Therefore, the present invention provides an embedded permanent magnet type induction motor which makes it possible to improve workability and productivity during the manufacture of motor bodies.
An embedded permanent magnet type induction motor according to the present invention comprises a rotor made of a plurality of rotor core plates laminated to an axial length L along its central axis. Each of the plurality of rotor core plates has a plurality of rotor slots in which coils, respectively, are to be embedded. The plurality of rotor slots are spaced apart from one another in a circumferential direction of the rotor. Each of the plurality of rotor core plates further has at least two holes in which permanent magnets are to be embedded.
According to an aspect of the present invention, each of the rotor core plates is provided with the plurality of rotor slots each inclined by an angle &agr; with respect to a radial direction of each of the rotor core plates. The rotor has the axial length L being made of laminations divided into at least two equal portions with respect to the central axis. The divided laminations are combined with one another so that one of the divided laminations is opposed to another in inclination of the angle &agr; and the plurality of rotor slots of one of the divided laminations are respectively superposed on the rotor slots of another at at least their ends closer to the central axis of the rotor to form a skew angle &bgr; in each of passages formed by the plurality of rotor slots extending along the axial length L.
REFERENCES:
patent: 2303893 (1942-12-01), Friedrich
patent: 2643350 (1953-06-01), Merrill
patent: 3126493 (1964-03-01), Honsinger
patent: 4139790 (1979-02-01), Steen
patent: 4358696 (1982-11-01), Liu et al.
patent: 4358697 (1982-11-01), Liu et al.
patent: 4506181 (1985-03-01), Jones et al.
patent: 4525925 (1985-07-01), Jones
patent: 4568846 (1986-02-01), Kapadia
patent: 4922152 (1990-05-01), Gleghorn et al.
patent: 5097166 (1992-03-01), Mikulic
patent: 5548172 (1996-08-01), Kliman et al.
patent: 5962944 (1999-10-01), Narita et al.
patent: 6088905 (2000-07-01), Boyd et al.
patent: 53020515 (1978-02-01), None
patent: 55077359 (1978-11-01), None
patent: 57186966 (1982-11-01), None
patent: 61177146 (1986-08-01), None
patent: 04275051 (1992-04-01), None
Hayashi Hidetoshi
Ikeda Hiroyuki
Morita Ikuro
Elkassabgi Heba
Ponomarenko Nicholas
Squire Sanders & Dempsey L.L.P.
Sumitomo Heavy Industrie's, Ltd.
LandOfFree
Embedded permanent magnet type induction motor which allows... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Embedded permanent magnet type induction motor which allows..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Embedded permanent magnet type induction motor which allows... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3266900