Study of Effect on Structural Strength of Locally Strengthened Rotor Lamination Stack through Virtual Validation

<div class="section abstract"><div class="htmlview paragraph">Rotor and Stator are the key constituents of an electric motor that are made of several laminates punched from a sheet metal and stacked together. The rotor stack is inserted with magnets at the punched-out pockets and is assembled with a shaft via press fitting. Rotor assembly being the rotating part of an E-Motor is subjected to centrifugal loads due to masses of magnets, lamination stack and shaft rotating at high speeds, temperatures and assembling loads because of which rotor laminates experience failures as the high strains develop in the regions on the laminate that support magnets. Typically, these high strain locations are the sections of the magnet pockets one on the outer diameter of the laminate and the other at the sections between the magnet pockets. Traditionally, these high strains are addressed by increasing the area of these sections, but this has a detrimental effect on the electromagnetic performance.</div><div class="htmlview paragraph">Instead of increasing the area of these sections, the proposed solution of local strengthening of the magnet pockets influences strength of these sections of the lamination stack. Such localized strengthening can be achieved through surface hardening, grain boundary refinement or using high strength magnet inserts. In this paper, an approach for investigating the effect of localized hardening on improvement in strength of rotor laminate is studied using Finite Element Analysis. A comparison is made between the locally strengthened and non-strengthened rotor laminate in terms of deformations and strains.</div></div>