Electric motor including outer rotor body, surrounding cover, and fan integrally formed with the cover
An outer rotor for use with a brushless DC electric motor includes a rotor body, a shaft coupled for co-rotation with the rotor body and defining a rotational axis, a cover surrounding at least a portion of the rotor body, and a fan integrally formed with the cover as a single piece. The fan includes a plurality of blades extending radially outward of the cover and configured to induce an airflow along an exterior surface of the cover in a direction parallel with the rotational axis.
1 . An outer rotor for use with a brushless DC electric motor, the outer rotor comprising:
a rotor body;
a shaft coupled for co-rotation with the rotor body, the shaft defining a rotational axis;
a cover surrounding at least a portion of the rotor body; and
a fan positioned at an axial end of and integrally formed with the cover as a single piece, the fan including a central hub adjacent the axial end of the cover, the central hub including a cylindrical outer peripheral surface and a plurality of blades extending radially outward from the cylindrical outer peripheral surface of the central hub, the blades configured to induce an airflow in a direction parallel with the rotational axis,
wherein the cover has a first radius, wherein the cylindrical outer peripheral surface has a second radius, and wherein the second radius is smaller than the first radius.
2 . The outer rotor of claim 1 , wherein each of the blades extends farther from the rotational axis than the cover.
3 . The outer rotor of claim 1 , wherein the cover and the fan are formed from plastic.
4 . The outer rotor of claim 1 , further comprising a magnet positioned on an interior surface of the rotor body, and wherein the magnet is coupled for co-rotation with the rotor body and the cover.
5 . The outer rotor of claim 1 , wherein the cover is overmolded onto the rotor body.
6 . The outer rotor of claim 5 , wherein the cover extends a length of the rotor body.
7 . A brushless DC electric motor comprising:
a stator; and
an outer rotor surrounding the stator, the outer rotor including
a rotor body,
a shaft coupled for co-rotation with the rotor body, the shaft defining a rotational axis,
a cover surrounding at least a portion of the rotor body, and
a fan positioned at an axial end of and integrally formed with the cover as a single piece, the fan including a central hub in front of the axial end of the cover and the rotor body, the central hub including a cylindrical outer peripheral surface and a plurality of blades extending radially outward from the cylindrical outer peripheral surface of the central hub, the blades configured to induce an airflow flowing from the fan to the cover in a direction parallel with the rotational axis.
8 . The brushless DC electric motor of claim 7 , wherein each of the blades extends farther from the rotational axis than the cover.
9 . The brushless DC electric motor of claim 7 , wherein the cover is overmolded onto the rotor body.
10 . The brushless DC electric motor of claim 7 , wherein the rotor body is press-fit within the cover.
11 . The brushless DC electric motor of claim 7 , wherein the fan is configured as an axial-flow fan.
12 . A brushless DC electric motor comprising:
a stator; and
an outer rotor surrounding the stator, the outer rotor including
a ring magnet defining a rotational axis,
a cover surrounding at least a portion of the ring magnet, and
a fan positioned at an axial end of and integrally formed with the cover as a single piece, the fan including a central hub adjacent the axial end of the cover, the central hub including a cylindrical outer peripheral surface and a plurality of blades extending radially outward from the cylindrical outer peripheral surface of the central hub, the blades configured to induce an airflow flowing from the fan to the cover in a direction parallel with the rotational axis,
wherein the cover has a first radius, wherein the cylindrical outer peripheral surface has a second radius, and wherein the second radius is smaller than the first radius.
13 . The brushless DC electric motor of claim 12 , wherein the cover is overmolded onto the ring magnet.
14 . The brushless DC electric motor of claim 12 , wherein the ring magnet is press-fit within the cover.
15 . The brushless DC electric motor of claim 12 , wherein the fan is configured as an axial-flow fan.