Patent ID: 7646125
Filing Date: 2010-01-12
Classification: H02K

Abstract:
1. A rotor of an electric motor, comprising: a rotor core having a plurality of magnet-retaining apertures; a plurality of permanent magnets individually received and retained in said plurality of magnet-retaining apertures of said rotor core; a resinous filler filling a gap defined between each of said magnet-retaining apertures and each of said permanent magnets and fixing said permanent magnets to said magnet-retaining apertures; and an engaging projection provided in said rotor core, said engaging projection tightly engaged with a portion of each of said plurality of permanent magnets received in said plurality of magnet-retaining apertures; wherein said engaging projection is formed only at a location adjacent to a first axial-end face of said rotor core, projects inside each of said plurality of magnet-retaining apertures, does not extend a whole length of the magnet-retaining aperture, and tightly engages only a first axial-end portion of a finally received permanent magnet; wherein each of said plurality of permanent magnets has a dimension smaller than a dimension of said rotor core as seen in an axial direction of said rotor core, and is provided with a first end surface disposed in close proximity to said first axial-end face of said rotor core and a second end surface disposed to be retracted into each of said plurality of magnet-retaining apertures from a second axial-end face of said rotor core opposite to said first axial-end face; and wherein said resinous filler is arranged, in each of said plurality of magnet-retaining apertures, to cover said second end surface of each of said plurality of permanent magnets and to fill said gap, by using a mold of an injection molding machine, the mold being formed in such a manner that each of a plurality of gates is opened to be opposed to said second end surface of each of said plurality of permanent magnets.