E-stack - Lamella stacks for electric motors

Bosch e-stack manufacturing enables additional product features. The accurate high-speed stamping process is executed differently than conventional methods, which allows more detailed product features and more design freedom. One example is the possibility to create smaller bridges in the rotor to reduce flux leakages to a minimum.

To improve power losses even more, annealing, welding, gluing, or a combination of annealing and gluing can be used. The annealing process reduces residual stresses caused by blanking of the lamella. Grain sizes are optimally controlled. As bonding methods, Bosch offers the option to glue or weld the stacks. These bonding processes can eliminate the use of interlocking. Bosch also employs a special strategy to minimize deformations of the lamella stack, resulting in high precision and flat lamella stacks. A new technique has been developed to weld the rotor on the inside to reduce the occurrence of short circuits between lamellae.

The use of adhesives to glue lamellae to a stack is an alternative. It is a stress-free way to join the lamellae, which minimizes associated power losses. It improves the flatness of the lamella and the noise behavior.