BMW I01 Product Information page 27

I01￿High-voltage￿Components
3.￿Electric￿Motor
In￿the￿graphic￿only￿the￿part￿of￿the￿stator￿without￿coil￿is￿shown.￿The￿rotor￿consists￿of￿a￿weight-optimized
support￿in￿the￿inside,￿a￿stack￿of￿sheets￿and￿permanent￿magnets,￿which￿are￿arranged￿in￿two￿layers.￿The
torque￿that￿can￿be￿generated￿by￿the￿machine￿is￿therefore￿increased.￿The￿rotor￿is￿shrink-fitted￿on￿the
drive￿shaft.
The￿number￿of￿pole￿pairs￿of￿6￿is￿a￿good￿ratio￿between￿the￿justifiable￿complexity￿of￿the￿design￿and
represents￿a￿constant￿torque￿curve￿for￿each￿revolution￿where￿possible.
The￿electrical￿machine￿of￿the￿I01￿does￿not￿have￿an￿oil￿filling.￿Only￿the￿two￿grooved￿ball￿bearings￿which
include￿a￿grease￿filling￿are￿lubricated.￿The￿cooling￿of￿the￿electrical￿machine￿is￿effected￿using￿coolant,
which￿is￿conveyed￿from￿the￿output￿of￿the￿electrical￿machine￿electronics￿to￿the￿electrical￿machine.￿In
the￿electrical￿machine￿the￿coolant￿flows￿through￿a￿spiral-shaped￿coolant￿duct,￿which￿runs￿at￿the￿outer
side.￿Two￿O-rings￿at￿the￿housing￿ends￿seal￿the￿coolant￿duct.￿The￿inside￿of￿the￿electrical￿machine￿is
therefore￿completely￿"dry".
Cooling￿of￿the￿electrical￿machine
Index
1
2
3
4
5
Explanation
Connection￿for￿coolant￿line￿(input￿of￿electrical￿machine,￿coming￿from￿the
electrical￿machine￿electronics)
Outer￿housing
Connection￿for￿coolant￿line￿(output￿of￿electrical￿machine,￿to￿the￿radiator)
O-ring
Cooling￿duct
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