In-wheel motor
An in-wheel motor, comprising: a rotor ( 14 ) of a surface permanent magnet type, wherein a plurality of permanent magnets ( 15 ) are fixed along an inner circumferential surface of the rotor; wedge-shaped protrusions ( 42 ) for fixing the permanent magnets ( 15 ) on the rotor ( 14 ); and a stator ( 30 ) disposed inside the rotor ( 14 ), wherein teeth ( 35 ) and slots ( 36 ) are alternately formed on an outer circumferential portion of the stator; wherein the number of the permanent magnets ( 15 ) is 32, and the number of the slots 36 is 24; wherein each of the permanent magnets ( 15 ) has chamfers ( 43 ) on each of the ends so that a magnetic flux cannot concentrate, and is convex toward the stator ( 30 ), in a cross-section perpendicular to a rotary axis of the rotor ( 14 ).
1. An in-wheel motor of an outer-rotor type for driving a wheel of an in-wheel motor vehicle having the motor incorporated in the wheel, comprising:
a rotor of a surface permanent magnet type, wherein a plurality of permanent magnets are fixed along an inner circumferential surface of the rotor;
wedge-shaped protrusions for fixing the permanent magnets on the rotor; and
a stator disposed inside the rotor, wherein teeth and slots are alternately formed on an outer circumferential portion of the stator;
wherein a number of the permanent magnets is 32, and a number of the slots is 24, and wherein in a cross-section of the permanent magnets perpendicular to a rotary axis of the rotor, each corner of the permanent magnets has a chamfer on each of ends so that a magnetic flux cannot concentrate, and the cross-section of the permanent magnets has a convex curved toward the stator at an inner side of the permanent magnets.
2. The in-wheel motor according to claim 1 , wherein the in-wheel motor satisfies the following Expression 1:
920
≦
Mw
3
×
Tw
3
×
Ri
2
×
Sin
Ma
8
×
1
100
≦
932
[
Expression
1
]
where, Mw is a half width of each of the permanent magnets in millimeters; Tw is a half width of each of the teeth in millimeters; Ri is an inside radius of the rotor in millimeters; and Ma is an angle between a tangential line on the permanent magnet at a point of contact between the wedge-shaped protrusion and the permanent magnet, and a bottom on the rotor side of the permanent magnet, in a cross-sectional shape of the permanent magnet along the direction perpendicular to the rotary axis of the rotor.
3. The in-wheel motor according to claim 2 , wherein the wedge-shaped protrusions are formed integrally with the rotor.
4. The in-wheel motor according to claim 1 , wherein each of the permanent magnets engages with the wedge-shaped protrusion on an end side thereof from a position of the chamfer.
5. An in-wheel motor of an outer-rotor type for driving a wheel of an in-wheel motor vehicle having the motor incorporated in the wheel, comprising:
a rotor of a surface permanent magnet type, wherein a plurality of permanent magnets are fixed along an inner circumferential surface of the rotor;
wedge-shaped protrusions for fixing the permanent magnets on the rotor; and
a stator disposed inside the rotor, wherein teeth and slots are alternately formed on an outer circumferential portion of the stator;
wherein a number of the permanent magnets is 32, and a number of the slots is 24,
wherein each of the permanent magnets has a chamfer on each of the ends so that a magnetic flux cannot concentrate, and is convex toward the stator, in a cross-section perpendicular to a rotary axis of the rotor, and
wherein the in-wheel motor satisfies the following Expression 1:
9
20
≦
Mw
3
×
Tw
3
×
R
i
2
×
Sin
Ma
8
×
1
1
0
0
≦
9
3
2
[
Expression
1
]
where, Mw is a half width of each of the permanent magnets in millimeters; Tw is a half width of each of the teeth in millimeters; Ri is an inside radius of the rotor in millimeters; and Ma is an angle between a tangential line on the permanent magnet at a point of contact between the wedge-shaped protrusion and the permanent magnet, and a bottom on the rotor side of the permanent magnet, in a cross-sectional shape of the permanent magnet along the direction perpendicular to the rotary axis of the rotor.
6. The in-wheel motor according to claim 5 , wherein the wedge-shaped protrusions are formed integrally with the rotor.