Electrical power-assisted steering systems
AssigneeTRW LucasVarity Electric Steering Ltd.
InventorRussell Wilson-Jones
Life of this patent
Estimating the term…
Abstract
An electrical power-assisted steering system is disclosed comprising an electric motor connected through a gearbox to act on a steering mechanism of the vehicle, the electric motor having a plurality of phase windings connected to a star point and switching means provided in at least one phase of the motor, the switching means being movable between a closed position in which current is able to flow in the phase windings, and an open position which prevents current flowing in a respective phase winding, The system incorporates a safety circuit operative when a fault develops to smooth out the transition between the presence and absence of servo support in assisting and not assisting by providing a prescribed period of damped operation as part of a shut-down phase.
Claims14
An electrical power-assisted steering system for a vehicle comprises an electric motor connected through a gearbox to act on a steering mechanism of said vehicle, in which said electric motor has a plurality of phase windings connected to a star point and a switch provided in at least one of said phases of said motor, said switch being movable between a closed position in which current is able to flow in said phase windings, and an open position which prevents current flowing in at least one of said phase windings, said system incorporating a safety circuit operative when a fault develops to smooth out a transition between a normal operation state and a shut-down state having;
- presence and absence of servo support in assisting and not assisting said steering mechanism respectively by providing a prescribed period of a damped operation as part of a shut-down state.
Dependencies are inferred from the claim text.