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AssigneeFujitsu General Limited
InventorsKenji Narita, Takashi Suzuki, Hiroyuki Okudera, Yuji Kawai, Yuji Souma, Koji Kawanishi, Yoshichika Fukuda
Estimating the term…
In a permanent magnet rotor type electric motor having a stator core generating a rotation magnetic field and provided therein with a rotor core in which each magnetic pole is formed by a permanent magnet, the rotor core is fabricated by coaxially and unitedly joining a first core member and a second core member, in which a first permanent magnet of a predetermined cross-section shape is embedded per magnetic pole in the first core member, and a second permanent magnet which is made of a different material and has a different cross-section shape from those of the first permanent magnet is embedded per magnetic pole in the second core member, thereby achieving the permanent magnet rotor type electric motor having the performance and size appropriate for the intended use.
A permanent magnet rotor type electric motor, having a stator core generating a rotation magnetic field and provided therein with a rotor core in which each magnetic pole is formed by a permanent magnet, wherein the rotor core comprises a first core member and a second core member which are unitedly joined together at the same axis with respect to the rotation axis of the rotor core, a first permanent magnet of a predetermined cross-section shape being embedded per magnetic pole in the first core member, and a second permanent magnet which is made of a different material and has a different cross-section shape from those of the first permanent magnet being embedded per magnetic pole in the second core member.
A permanent magnet rotor type electric motor, having a stator core generating a rotation magnetic field and provided therein with a rotor core in which each magnetic pole is formed by a permanent magnet, wherein the rotor core comprises a first core member and a second core member which are unitedly joined together at the same axis with respect to the rotation axis of the rotor core, a first permanent magnet of a predetermined cross-section shape being embedded per magnetic pole in the first core member, and a second permanent magnet which is made of a different material and has a different cross-section shape from those of the first permanent magnet being embedded per magnetic pole in the second core member, and the second permanent magnet is disposed within a shadow area of a cross-section shape of the first permanent magnet in the second core member.
Dependencies are inferred from the claim text.
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The rotor consisting of magnets or groups of magnets arranged with alternating polarity: magnets embedded in the magnetic core, e.g. interior…
Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]: having a flux concentration effect
Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical…:…
Machines with more than one rotor or stator: machines with one stator and two or more rotors
Term ended 20 Oct 2018 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
This invention relates to an electric motor having a permanent magnet in a rotor, such as Brushless DC motor, and more specifically, to an electric motor appropriate for the use as, for example, a driving source of a compressor of an air conditioner or the like, and capable of achieving a performance, size and production cost relative to its usage.
2. Description of the Related Art
The present invention will be described further hereinafter, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a diagrammatic plane view showing the first embodiment according to the present invention;
FIG. 2 is a sectional view taken along the d-axis of a rotor core applied in the first embodiment of FIG. 1;
The first embodiment of a permanent magnet rotor type electric motor according to the present invention will be described below with reference to FIG. 1 to FIG. 4. The permanent magnet rotor type electric motor is composed of a stator core 17 generating a rotation magnetic field, and a rotor core 10 which is rotatably provided in the stator core 17. In the embodiment, the stator core 17 has 24 slots and is provided with armature winding in three phases (U-phase, V-phase and W-phase). In this point, the armature winding positioned on the outer circle side is the U phase, the armature winding positioned on the inner circle side is the W phase, and the armature winding between the U and W phases is the V phase. The number of slots and the form of the armature winding can be selectively decided.
As shown in a sectional view of FIG. 2, the rotor core 10 is constructed by coaxially joining a first core member 12 in which first permanent magnets 11 are embedded to a second core member 14 in which second permanent magnets 13 are embedded. At the rotative center of the rotor core 10, a center hole 16 for passing a rotating shaft (not shown) is opened.
In the embodiment, the first permanent magnet 11 is made of a ferrite magnet, and the second permanent magnet 13 is made of a rare-earth magnet.