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Chassis Systems

Electrically Powered Steering

Contact: North America

TRWAutomotiveSteering Systems4505 W. 26 Mile Rd.Washington, MI 48094USATel: +1.586.232.7200

Fax: +1.586.232.8356

Contact: Europe

TRWAutomotiveSteering SystemsTRWAutomotive GmbHD-40547 DsseldorfGermanyTel: +49.211.584.0

Fax: +49. 211.584.595

www.trw.com

TRWAutomotive 2009TRWis the name and mark of TRW

Column DriveEPS

Electrically Assisted Steering (EAS) by TRW is aninnovative range of power-assisted steering products thateliminate the connection between steering system andengine. One sub-set of the EAS product range is theColumn Drive Electric Power Steering (EPS) System.

In many instances, the optimal way of integrating an EPSdrive into the vehicle is by placing it next to the steeringcolumn in the vehicle interior. In this architectural variant,the additional torque to assist the driver is provided by theelectric motor and is transferred to the steering shaft via a

worm gear. This approach is particularly useful in smallervehicles with a limited amount of space in the enginecompartment. In relation to the environmental conditionsin the engine compartment, the requirements regardingthe temperature range and the sealing of the servo drivefor the vehicle interior are considerably less, which has abeneficial effect on the cost of the system.

The electronic control unit (ECU) is integrated into thedrive assembly and contains the control algorithms forcreating the dynamic steering response, something whichcannot be achieved using hydraulic steering systems.

Like all Electrically Powered Steering systems, theColumn Drive EPS System continually monitors the driveractivity on the steering wheel and only consumes powerto support the driver when steering assist is really needed.This reduction in the amount of energy required by thesteering system can make a significant contribution tolowering fuel consumption and CO2 tailpipe emissions.

The system is commonly manufactured as a steeringcolumn module with a crash energy absorber integrated

into the steering column tube. The steering columnmodule can be optionally equipped with horizontal andvertical steering wheel adjustments.

TRWs Column Drive EPS systems have been in seriesproduction for approximately 8 years, sold around 10million units, and are continually under development forenhanced performance and cost-effectiveness.

SteeringSystems

Features:

EPS steering column module with in-builtpackaging flexibility, crash and adjustment options

Scaleable system sizes from 40-100Nm maximumtorque output

PMAC motor with low rotational inertia Low-noise worm gear Non-contacting driver torque sensor with optional

steering angle measurement

Powerful ASIL D compliant ECU for incorporatingadvanced steering functions including inputs forsupporting Driver Assist Functions

Advantages:

Lower fuel consumption / CO2emission reduction Tunable steering assistance characteristics 'End of Line' calibration plus built in diagnostics Simplified vehicle logistics Simplified supplier chain logistics