Electrically Powered Steering
TRW offers the largest selection of Electrically Assisted Steering (EAS) technologies in the world, and was first-to-market with Electrically Powered Hydraulic Steering systems for Europe. TRW’s expertise in the field has led it to offer three key types of EAS systems: Column Drive Electrically Powered Steering (EPS), Rack Drive EPS and Electrically Powered Hydraulic Steering (EPHS).
TRW’s EPS technologies are a key enabler for advanced comfort and safety systems, such as Park Assist, Steering Torque Control and Lane Keeping Systems.
Column Drive EPS
Designed initially for the small-car segment, TRW’s Column Drive EPS offers a modular and scalable design that covers a range of forces from 4.0kN to 10kN. One of the major benefits of the Column Drive system is its clever packaging. Its location in the passenger compartment enables reduced temperature and sealing requirements compared with systems situated under the hood. Used on a wide variety of European and Asian passenger cars, the technology has advanced to the latest version which uses an innovative torque sensor that comprises an inductive modular design while being fully capable of 5*NCAP crash requirements and providing class-leading vehicle dynamics.
Rack/Belt Drive EPS
The most efficient EPS system offered by TRW, Belt Drive EPS (also referred to as Rack Drive) is a solution that integrates a brushless motor, toothed belt, and ball nut assembly with pulley and bearing in one unit. This setup results in lower inertia and friction for high power applications, as well as a more direct steering feel and superior response. The integrated ECU sits alongside the motor on the rack, providing a flexible and cost-effective package. As technologies move forward, the Belt Drive EPS solution is available in a smaller and more flexible package, helping to satisfy customers' packaging requirements. Belt drive technology is particularly suited to cars within the European D segment and above, and the TRW Belt Drive systems operate directly from 12V power on rack loads up to 13.5kN.
EPS is extremely efficient when compared to a power rack and pinion pump, using only 10 percent of the energy and only when the driver demands it. With no energy drag on the engine, EPS systems offer a fuel savings of up to 0.33L/100km, with a corresponding reduction in carbon dioxide emissions of approximately 8g/km.