Integration of park lock, rotor position sensing, and brush system into a single module for electric axles simplifies design, reduces space requirements, and lowers costs.
Vitesco Technologies, an international provider of advanced drive technologies and electrification solutions, recently presented its new Rotor Lock Actuator at the SIA Powertrain expo in Lille, France, from June 19 to 20, 2024.
This electric vehicle (EV) module merges three essential functions into a single unit: a park lock feature, precise rotor position sensing, and optionally, the brush system for externally excited synchronous machines (EESM). This integration diminishes complexity, reduces the space needed on the e-axle, and lowers costs for consumers.
Offering more functionality at reduced costs, most EVs traditionally employ a mechanical park lock in the reducer gearbox along with park brakes on the wheels—a conventional solution for secure vehicle parking. However, this setup occupies significant space. The innovative rotor lock approach transfers the park lock functionality from the gearbox to the rotor shaft of the e-machine, resulting in a more streamlined and cost-effective system design.
Robert Paul, Head of the Actuation business unit at Vitesco Technologies, points out that the key to the success of electric mobility is the reduction of costs and complexity. He explains that by combining up to three functions into one product, their Rotor Lock Actuator offers high functionality while efficiently optimizing space and costs. Positioned at the rotor shaft’s end, the smaller actuator integrates seamlessly into the vehicle’s drive system. This high degree of mechatronic integration conserves space, enabling more compact vehicle packaging. Additionally, this placement allows for the inclusion of other functions in the module, such as the brush system for EESM and the inductive Rotor Position Sensor, eliminating the need for separate control units, sensors, and harnesses, thereby further reducing costs.
The module’s reliability and safety are enhanced through implemented sensing redundancy, robust cyber security measures, and advanced internal diagnostics. The Rotor Lock Actuator integrates smoothly into the drivetrain and communication networks, facilitating easy installation. Its inductive Rotor Position Sensor feature increases range by optimizing motor commutation control. It also improves parking safety by minimizing vehicle movement when the rotor lock is engaged. The smart interface design between the locking element and rotor prevents accidental lock engagement while driving, activating and deactivating in less than 250 milliseconds.
