Rotor and method of manufacturing the same

1. A rotor comprising:

a rotor core fixedly provided on a rotational shaft and having a hole, the shaft extending along an axial direction thereof;

a magnet inserted into the hole; and

a filling portion injected into a gap between a side surface of the hole and a side surface of the magnet, wherein:

the filling portion is injected into the gap at a first hole on an end surface of the rotor core and discharged from a second hole on the end surface of the rotor core,

at least one of the magnet and the rotor core has a spread-promoting portion formed therein for promoting spread of the filling portion injected into the gap, and

the spread-promoting portion comprises a plurality of elongated elements formed on the magnet, a direction in which the elements elongate being non-parallel to the axial direction of the shaft.

2. The rotor according to claim 1 , wherein the spread-promoting portion promotes the spread of the filling portion on a side of magnet that is located on the radially outer side of the rotor core.

3. The rotor according to claim 1 , wherein:

on a cross section with respect to the axial direction, the dimension in a first direction of the hole and magnet each is relatively small and the dimension in a second direction thereof that is orthogonal to the first direction is relatively large, and

the spread-promoting portion is formed to extend in the second direction.

4. The rotor according to claim 1 , wherein:

the gap includes a first portion with a relatively large width and a second portion with a relatively small width, and

in a portion of the magnet or said rotor core that faces the second portion, the spread-promoting portion is provided.

5. The rotor according to claim 1 , wherein the spread-promoting portion includes at least one of a groove, a chamfered portion and a recessed portion formed in the magnet or the rotor core.

6. A rotor comprising:

a rotor core fixedly provided on a rotational shaft and having a hole, the shaft extending along an axial direction thereof;

a magnet inserted into the hole; and

a filling portion injected into a gap between a side surface of the hole and a side surface of the magnet, wherein

the filling portion is injected into the gap at a first hole on an end surface of the rotor core and discharged from a second hole on the end surface of the rotor core,

at least one of said magnet and the rotor core has a plurality of grooves formed therein for promoting spread of the filling portion injected into the gap, and

the grooves are formed obliquely relative to the axial direction of the shaft, and/or the grooves are curved toward the axial direction of the shaft or a direction opposite to the axial direction.

7. A rotor comprising:

a rotor core fixedly provided on a rotational shaft and having a hole;

a magnet inserted into the hole, the magnet having a width; and

a filling portion injected into a gap between a side surface of the hole and a side surface of the magnet, wherein the magnet has a plurality of grooves formed therein for promoting spread of the filling portion injected into the gap, the grooves extending across the full width of the magnet,

wherein the filling portion is injected into the gap at a first hole on an end surface of the rotor core and discharged from a second hole on the end surface of the rotor core.