Electric motor with integrated self-supporting spindle for a mower
An example assembly includes a housing having a motor housing portion and a spindle housing portion, wherein the spindle housing portion comprises a central tube; an electric motor disposed within the motor housing portion of the housing, wherein the electric motor has a rotor; a spindle coupled to the rotor of the electric motor, wherein the spindle is disposed within the central tube of the spindle housing portion; one or more bearings disposed within the central tube and supporting the spindle.
1 . An assembly comprising:
a housing having a motor housing portion and a spindle housing portion, wherein the spindle housing portion comprises a central tube;
an electric motor disposed within the motor housing portion of the housing, wherein the electric motor has a rotor;
a spindle coupled to the rotor of the electric motor, wherein the spindle is disposed within the central tube of the spindle housing portion;
one or more bearings disposed within the central tube and supporting the spindle; and
an inverter board, wherein the inverter board is: mounted within the housing, wherein the inverter board comprises a plurality of transistors mounted to a first surface of the inverter board, and a plurality of capacitors mounted to a second surface of the inverter board opposite the first surface, or attached to a housing cover mounted to the housing to form an enclosure in which the electric motor is disposed.
2 . The assembly of claim 1 , further comprising:
a mounting spacer mounted about the spindle and configured to determine a position of a blade to be coupled to the assembly.
3 . The assembly of claim 1 , wherein the housing comprises one or more conical sections connecting the motor housing portion to the spindle housing portion.
4 . The assembly of claim 1 , wherein the housing further comprises one or more cylindrical portions inside the housing, wherein the plurality of transistors interface with the one or more cylindrical portions to transfer heat from the plurality of transistors to the housing.
5 . The assembly of claim 1 , wherein the electric motor further comprises a stator mounted within the housing, wherein the rotor is mounted within the stator, wherein the stator interfaces with a shoulder formed within the housing to transfer heat from the stator to the housing.
6 . The assembly of claim 5 , further comprising:
a housing cover mounted to the housing to form an enclosure in which the electric motor is disposed, wherein the housing cover comprises one or more arcuate protrusions interfacing with the stator to transfer heat from the stator to the housing cover.
7 . The assembly of claim 1 , further comprising:
a terminal block assembly comprising:
a terminal block housing having (i) an external housing portion disposed substantially outside the housing of the assembly, and (ii) an internal housing portion disposed substantially inside the housing of the assembly, wherein the external housing portion comprises a plurality of input terminals, and wherein the internal housing portion comprises a plurality of output terminals respectively coupled to the plurality of input terminals; and
a seal positioned in a groove formed in the terminal block housing to seal the terminal block assembly against the housing of the assembly.
8 . The assembly of claim 1 , wherein the spindle is configured to drive a blade, and wherein the assembly further comprises:
a breakaway configuration, wherein as the blade is forced into a sudden stop, causing a torque exceeding a threshold torque to be applied to the spindle, the breakaway configuration allows the rotor of the electric motor and the spindle coupled thereto to continue rotating.
9 . The assembly of claim 8 , wherein the breakaway configuration comprises:
a blade adapter driver configured to rotate with the spindle, wherein the blade adapter driver comprises a plurality of teeth; and
a blade adapter having a plurality of holes respectively receiving the plurality of teeth of the blade adapter driver, thereby causing the blade adapter driver to rotate the blade adapter, wherein the blade adapter further comprises one or more receptacles configured to receive the blade, such that the one or more receptacles cause the blade to rotate with the blade adapter, and wherein the one or more receptacles are configured to break or bend to allow the spindle to continue rotating as the blade is forced into the sudden stop.
10 . The assembly of claim 9 , further comprising:
a conical spring washer interfacing with the blade adapter driver; and
a screw that is threadedly engaged with the spindle to rotate therewith, wherein the screw clamps the conical spring washer against the blade adapter driver, causing the blade adapter driver to rotate with the spindle.
11 . An assembly comprising:
a housing having a motor housing portion and a spindle housing portion, wherein the spindle housing portion comprises a central tube;
an electric motor disposed within the motor housing portion of the housing, wherein the electric motor has a rotor disposed inside a stator;
a spindle coupled to the rotor of the electric motor, wherein the spindle is disposed within the central tube of the spindle housing portion; and
one or more bearings disposed within the central tube and supporting the spindle, wherein the one or more bearings comprise: a first bearing mounted at a first end of the spindle within the central tube under the electric motor, and a second bearing mounted at a second end of the spindle within the central tube.
12 . The assembly of claim 11 , further comprising:
a wave spring mounted within the central tube and applying a biasing force on an outer race of the first bearing; and
a retaining ring interfacing with the second bearing and configured to retain the spindle, the first bearing, and the second bearing within the central tube.
13 . The assembly of claim 11 , further comprising:
an airflow cone mounted about a portion of the central tube and configured to rotate with the spindle, while protecting the second bearing from debris.
14 . An assembly comprising:
a housing having a motor housing portion and a spindle housing portion, wherein the spindle housing portion comprises a central tube;
an electric motor disposed within the motor housing portion of the housing, wherein the electric motor has a rotor, wherein the rotor of the electric motor comprises (i) a rotor lamination stack comprising a plurality of laminations, each lamination comprising a central ring and a plurality of petals emanating radially outward from the central ring, and (ii) a plurality of magnets disposed in a spoke arrangement between respective petals of the plurality of petals;
a rotor clamping plate interfacing with the rotor lamination stack;
a plurality of screws coupling the rotor clamping plate to the rotor lamination stack, wherein a screw of the plurality of screws is disposed at a magnetically-neutral position equidistant from two adjacent magnets of the plurality of magnets; and
a spindle coupled to the rotor of the electric motor, wherein the spindle is disposed within the central tube of the spindle housing portion.
15 . The assembly of claim 14 , wherein the rotor clamping plate comprise a hub having an internal taper, wherein the spindle comprises a tapered end received within and complies to the internal taper of the hub, such that the tapered end of the spindle and the internal taper of the hub form a self-holding taper arrangement for transmitting torque from the hub to the spindle.
16 . A mower comprising:
a source of electric power;
a mower deck; and
one or more assemblies mounted to the mower deck and coupled to respective blades, wherein an assembly of the one or more assemblies comprises:
a housing having a motor housing portion and a spindle housing portion, wherein the spindle housing portion comprises a central tube,
an electric motor disposed within the motor housing portion of the housing, wherein the electric motor has a stator and a rotor, wherein the source of electric power is configured to provide electric power to wire windings of the stator,
a spindle coupled to the rotor of the electric motor, wherein the spindle is disposed within the central tube of the spindle housing portion, wherein the spindle is configured to drive a blade of the respective blades,
one or more bearings disposed within the central tube and supporting the spindle, and
a breakaway configuration comprising: (i) a blade adapter driver configured to rotate with the spindle, wherein the blade adapter driver comprises a plurality of teeth; and
(ii) a blade adapter having a plurality of holes respectively receiving the plurality of teeth of the blade adapter driver, thereby causing the blade adapter driver to rotate the blade adapter, wherein the blade adapter further comprises one or more receptacles configured to receive the blade, such that the one or more receptacles cause the blade to rotate with the blade adapter, and wherein the one or more receptacles are configured to break or bend to allow the spindle to continue rotating as the blade is forced into a sudden stop.
17 . The mower of claim 16 , wherein the assembly further comprises:
a mounting spacer mounted about the spindle and configured to determine position of a blade associated with a distance of the blade from ground.