BMW I01 Product Information page 40

I01￿High-voltage￿Components
3.￿Electric￿Motor
An￿axle￿transmission￿oil￿known￿from￿conventionally￿driven￿BMW￿vehicles￿is￿used￿as￿transmission
oil￿(manufacturer￿designation,￿e.g.￿Castrol￿BOT-448).￿The￿transmission￿housing￿is￿also￿used￿as￿an
oil￿sump￿and￿holds￿the￿full￿capacity￿of￿0.5 l￿transmission￿oil.￿The￿spur￿gear￿units￿and￿the￿differential
run￿in￿the￿transmission￿oil￿and￿ensure￿the￿entire￿transmission￿is￿lubricated￿(oil￿sump￿lubrication).￿The
transmission￿oil￿is￿designed￿for￿the￿operating￿life￿of￿the￿I01￿meaning￿there￿is￿no￿need￿for￿a￿replacement
of￿the￿transmission￿oil.￿Nevertheless,￿there￿is￿an￿oil￿drain￿plug,￿as￿well￿as￿an￿oil￿filler￿plug,￿with￿which
the￿oil￿level￿can￿also￿be￿checked.￿These￿are￿shown￿in￿a￿graphic￿in￿the￿chapter￿"Mechanical￿interfaces".
The￿transmission￿is￿not￿integrated￿in￿the￿cooling￿system￿of￿the￿electric￿motor￿and￿therefore￿has￿no
connections￿for￿coolant￿lines.￿The￿heat￿in￿the￿transmission￿which￿arises￿during￿operation￿is￿low.
Sufficient￿heat￿is￿discharged￿via￿the￿air￿flowing￿by￿at￿the￿transmission￿housing￿and￿the￿connection
for￿the￿electrical￿machine.￿The￿temperature￿in￿the￿transmission￿remains￿in￿a￿range￿up￿to￿a￿maximum
120 °C,￿for￿which￿the￿components￿and￿the￿transmission￿oil￿are￿designed.￿The￿transmission￿can,
however,￿also￿absorb￿significantly￿lower￿temperatures:￿When￿driving￿off￿after￿a￿long￿immobilization
period￿the￿components￿have￿the￿ambient￿temperature.￿As￿a￿result￿of￿the￿large￿temperature￿range
excess￿pressure￿or￿a￿vacuum￿would￿occur￿in￿a￿completely￿tight￿housing.￿To￿avoid￿this￿there￿is￿a
bleeding￿hole￿above￿at￿the￿transmission￿housing.￿It￿has￿a￿cap￿to￿protect￿against￿dirt￿contamination.
The￿bleeding￿hole￿is￿also￿shown￿in￿a￿graphic￿in￿the￿chapter￿"Mechanical￿interfaces".
3.2.3.￿Mechanical￿interfaces
Mounting￿and￿torque￿support
The￿mounting￿and￿support￿of￿the￿drive￿torque￿is￿not￿only￿related￿to￿the￿transmission,￿but￿also￿the
entire￿drive￿unit￿comprising￿the￿electrical￿machine,￿transmission￿and￿electrical￿machine￿electronics.
The￿weight￿force￿and￿drive￿torque￿are￿transmitted￿to￿the￿rear￿axle￿module￿via￿engine￿support￿arm￿and
anti-roll￿bar￿link￿and￿from￿there￿to￿the￿body.
Components￿of￿the￿transmission￿visible￿from￿the￿outside
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