US Patent No. 9,106,118

ROTOR HAVING PROJECTIONS FOR POSITIONING PERMANENT MAGNETS AND ELECTRIC MOTOR INCLUDING SUCH ROTOR


Patent No. 9,106,118
Issue Date August 11, 2015
Title Rotor Having Projections For Positioning Permanent Magnets And Electric Motor Including Such Rotor
Inventorship Yasunori Sugimoto, Yamanashi (JP)
Assignee Fanuc Corporation, Yamanashi (JP)

Claim of US Patent No. 9,106,118

1. A rotor for an electric motor comprising:
a rotor core having a first end and a second end in a direction of a rotational axis and having an outer circumferential surface,
on which a plurality of projections extending from the first end toward the second end and projecting outwardly in a radial
direction are formed; and

a plurality of permanent magnets arranged between the plurality of projections and on the outer circumferential surface of
the rotor core,

wherein each of the plurality of projections has a first inclined side which inclines with respect to the direction of a rotational
axis, such that a space defined between the projections adjacent to each other becomes smaller in size at the second end than
at the first end,

wherein each of the plurality of permanent magnets has a second inclined side which inclines with respect to the direction
of a rotational axis, such that a width of the permanent magnet defined in a direction orthogonal to the direction of a rotational
axis becomes smaller at the second end than at the first end,

wherein the first inclined side of the projection and the second inclined side of the permanent magnet which face each other
incline, respectively, so as to define the same angle with respect to the direction of a rotational axis,

wherein the first inclined side of the projection and the second inclined side of the permanent magnet extend from the second
end toward the first end only on a part of the projection and the permanent magnet, respectively, and

wherein each of the plurality of projections has the first inclined side only on one side thereof, and each of the permanent
magnet has the second inclined side only on one side thereof.