US 5,400,250 AGranted

Rear wheel steering device

AssigneeMazda Motor Corporation

InventorHiroshi Ohmura

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Abstract

A rear wheel is provided with a steering characteristic such that a vehicle runs on a cornering path with a longitudinal center line of the vehicle substantially aligned with a tangential line of the cornering path throughout cornering movement. A fail judge device is provided for judging when a rear wheel steering device failure is present in light of a criterion based on a rear wheel steering. A criterion change device is also provided for changing the criterion between a transitional cornering condition, in which the vehicle is in an initial stage of a cornering movement just after a steering operation and before a cornering force acting on the vehicle body reaches a substantial value, and a steady cornering condition, in which the cornering force has reached the substantial value. A reverse phase control can be properly performed without failure judgment. This assures that a desirable driving feeling is provided for the driver when cornering as well as improved safety.

Claims11

Dependent claims

A rear wheel steering device for steering a rear wheel so that a vehicle runs on a cornering path with a longitudinal center line of the vehicle substantially aligned with a tangential line of the cornering path throughout cornering comprising:

fail judge means for judging a rear wheel steering device failure based on a predetermined criterion corresponding to a cornering condition related to rear wheel steering;
cornering condition detecting means for detecting, as said cornering condition, at least one of a transitional cornering condition, in which the vehicle is in an initial stage of a cornering movement just after a steering operation and before a cornering force acting on a vehicle body reaches a substantial value, and a steady cornering condition, in which the cornering force has reached the substantial value;
and
criterion change means for changing said predetermined criterion as a cornering condition detected by said cornering condition detecting means changes between said transitional cornering condition and said steady cornering condition.

1 more element

Dependencies are inferred from the claim text.