| 摘要 |
PURPOSE:To ensure the stability of a vehicle during running on a road surface having a low friction, by changing characteristics under a predetermined condition during running in such a low friction road surface that the drive condition of the vehicle is sensitive to change in the steering ratio characteristic of the vehicle. CONSTITUTION:A vehicle four wheel steering device in which there are provided a plurality of steering ratio characteristics and these steering ratio characteristics are variable, there are provided a road surface friction detecting means 1 for detecting the friction of a road surface, and a friction discriminating means 2 receiving a signal from the detecting means 1, for discriminating whether the road surface friction is high or low. Further there is provided a characteristic changing means 3 receiving a signal from the discriminating means 2, for allowing steering ratio characteristics to be changed when a predetermined condition is satisfied if the road surface friction is low. Further, the characteristics are allowed to be changed for the first time under such a condition that no substantial affection is given to change in the behavior of the vehicle during running on a low friction road surface such as a snow covered road or the like. |
