IDAC were required by their client to carry out a prototype design investigation of a laminated rotor to be used in a hydraulic steering system in a car. A series of analyses were carried out on various rotor designs. Two main designs were investigated:
A hollow laminated core
A drilled aluminium core
The objective of the investigation for both of the above designs was to evaluate the reduction of weight by hollowing the hub section, whilst maintaining mechanical integrity. Results were required for:
Stresses due to rotation
Effects due to heating
Torque applied at one end of the shaft
The rotor was composed of 435 laminations 0.35 mm thick stacked axially onto the shaft. A keyway on the shaft retained the laminations in rotation. Axial location was provided by the rotor endplates clamped by the nut and lock washer. A banding layer was wound onto the outer circumference of the laminations and was included to retain the structure against radial loads.
The laminations include 8 shaped magnet pockets; the cavity around the magnets was filled by a structural epoxy adhesive. The area around the magnets and banding was of particular interest.
The operating conditions (speed, temperature, fundamental frequency) and material properties of all materials were supplied by the client.