Automobile manufacturers and suppliers are facing new challenges when it comes to components for electric motors. The example of the housing of an electric motor shows how big these challenges are: Compared to a transmission housing, this has to be manufactured within significantly tighter tolerances, since the accuracy has a decisive influence on the efficiency of the motor.
In addition, due to the special structure, such as integrated cooling channels, the electric motor housing is usually significantly thinner than a transmission housing. In addition, bearing bushes made of steel materials are pressed into some of these housings. Special protection shields in the tool ensure that steel chips do not come into contact with the aluminium surfaces during processing and damage them.
Machining requirements and features of different housing types
Description: Highly integrated, complex housing with stator mount, transmission mount and connection for the power electronics. High functional integration saves assembly costs. Compact design. Complex cast housing as a result.
FEATURES
Stator incorporated directly in the housing or via a stator carrier / cooling jacket
Stator bore with stages and flat surfaces as functional surfaces
A bearing bore of the rotor is integrated coaxially with the stator bore in the housing
Positioning of the second bearing cover via dowel pins or fitting surfaces; second bearing bore must be coaxial
Bearing bores of transmission stages integrated in the housing; high concentricity and positional accuracy are required
Cooling channels partially integrated in the housing
Complex cast aluminium housing
MACHINING REQUIREMENTS
Elaborate contour trains with several diameter levels ( high cutting forces and large machining volume)
Mixed processing (-> chip separation / removal)
Interrupted cuts (-> contacting, cooling circuit)
15°-30° flat lead-in chamfers (-> flow chip formation and high radial forces)
