Four-wheel steering system for automotive vehicles

Claim 1

A four-wheel steering system for an automotive vehicle having a pair of dirigible front road wheels and a pair of dirigible rear road wheels, comprising: a front wheel steering mechanism operable in response to a steering operation to steer the front road wheels; a rear wheel steering mechanism including an operation rod axially movable in response to operation of said front wheel steering mechanism to steer the rear road wheels; a linkage arranged in a fore-and-aft direction of the vehicle and having one end drivingly connected to said front wheel, steering mechanism; and a connecting mechanism assembled in combination with said rear wheel steering mechanism and being drivingly connected to the other end of said linkage for effecting axial movement of the operation rod in response to operation of said front wheel steering mechanism; wherein said connecting mechanism comprises: a housing to be mounted on a body structure of the vehicle; a carrier rotatably mounted within said housing and being arranged to rotate about a first axis perpendicular to the longitudinal axis of said operation rod; drive means mounted on said housing to effect rotary motion of said carrier about said first axis; a bell crank rotatably mpunted on said carrier and arranged to rotate about a second axis in parallel with the longitudinal axis of said operation rod when said carrier is retained in a neutral position, said bell crank having a first arm extending therefrom at a predetermined angle to said first axis and a second arm extending therefrom along said first axis; a first link having one end pivotally connected with the first arm of said bell crank and the other end operatively connected to said linkage to be moved along said first axis in response to operation of said front wheel steering mechanism; and a second link pivotally connected with the second arm of said bell crank and operatively connected to said operation rod.