Permanent magnet rotor
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsShinya Naito, Haruyoshi Hino
Life of this patent
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Abstract
To decrease torque ripples and cogging torque, a rotor for an electrical motor, an electrical generator, or the like, includes lengths of permanent magnets embedded in a plurality of slit sections in respective layers. In an embodiment having three layers, the permanent magnets have lengths L1, L2 and L3 in order as viewed from the outside circumference side of the rotor core and generate respective total magnetic fluxes of Φ1, Φ2, Φ3, respectively, when the rotor is assembled in a rotary electric device. The lengths have a relation L1<L2<L3, and the magnetic fluxes have a relation Φ1<Φ2<Φ3.
Claims14
A permanent magnet rotor comprising a rotor core that comprises a plurality of magnetic poles, the rotor core comprising a plurality of permanent magnets embedded in slit sections formed in layers for each magnetic pole, the layers comprising a radially innermost layer, a least one intermediate layer, and a radially outermost layer, the radially innermost layer and the at least one intermediate layer each including at least one vacant slit section in which no permanent magnet is embedded, the vacant slit section in the radially innermost layer being larger than the vacant slit section in the intermediate layer, the permanent magnets embedded in the slit sections in each layer generating magnetic flux, the permanent magnets embedded in the slit sections of the radially innermost layer generating more magnetic flux than the permanent magnets embedded in the slit sections of the at least one intermediate layer.
A permanent magnet rotor comprising a rotor core that comprises a plurality of magnetic poles, the rotor core comprising a plurality of permanent magnets embedded in slit sections formed in layers for each magnetic pole, the layers comprising a radially innermost layer, at least one intermediate layer, and a radially outermost layer, the permanent magnets in the radially innermost layer, the at least one intermediate layer and the radially outermost layer selected to have respective residual flux densities and respective total magnetic flux, the residual flux density of the permanent magnet in the at least one intermediate layer being greater than the residual flux density in the radially innermost layer, the residual flux density of the permanent magnet in the radially outermost layer being greater than the residual flux density of the permanent magnet in the at least one intermediate layer, the total magnetic flux generated by the permanent magnet in the radially innermost layer being greater than the total magnetic flux generated by the permanent magnet in the at least one intermediate layer, and the total magnetic flux generated by the permanent magnet in the at least one intermediate layer being greater than the total magnetic flux generated by the permanent magnet in the radially outermost layer.
A permanent magnet rotor comprising a rotor core that comprises a plurality of magnetic poles, the rotor core comprising a plurality of permanent magnets embedded in slit sections formed in layers for each magnetic pole, the layers comprising a radially innermost layer, at least one intermediate layer, and a radially outermost layer, each layer having a respective mean residual magnetic flux density determined by the kind of permanent magnet in each layer and by a length of the permanent magnet in each layer, at least one of the layers comprising a plurality of slit sections, the plurality of slit sections in the at least one of the layers comprising at least a first kind of permanent magnet having a first residual magnetic flux density and at least a second kind of permanent magnet having a second residual magnetic flux density different from the first residual magnetic flux density, the at least one of the layers having a mean residual magnetic flux density determined by the first and second residual magnetic flux densities and a length of the first kind of permanent magnet and a length of the second kind of permanent magnet in the at least one of the layers, the mean residual magnetic flux densities of the layers and the lengths of the permanent magnets in the layers selected so that the mean residual magnetic flux density of the radially innermost layer is smaller than the mean residual magnetic flux density of the at least one intermediate layer and so that the mean residual magnetic flux density of the at least one intermediate layer is less than the mean residual magnetic flux density of the radially outermost layer, and so that a total magnetic flux generated by the permanent magnet in the radially innermost layer is greater than a total magnetic flux generated by the permanent magnet in the radially outermost layer.
Dependencies are inferred from the claim text.