HYDRAULIC DAMPING BUSHING

A vibration damping device of the bushing-type includes a rigid outer housing and a rigid inner member, having a first side and a second side, which is substantially enclosed by the outer housing. A first vibration absorbing resilient body is interposed between the first side of the inner member and the outer housing. The first body is made of an elastomeric material having a first spring rate. A second vibration absorbing resilient body is interposed between the second side of the inner member and the outer housing. The second body is made of an elastomeric material having a second spring rate which is different from the first spring rate such that a deflection of the rigid inner member toward one of the first and second bodies will be resisted more strongly than a deflection of the rigid inner member toward the other of the first and second bodies. A first fluid chamber is defined in the second body and a second fluid chamber is defined between the second body and the outer housing. The second fluid chamber is in fluid communication with the first chamber through a first fluid passageway. A plate is moveably mounted in the first passageway for movement perpendicular to a longitudinal axis of the device. The plate controls a flow of fluid through the first passageway to a varying extent depending upon the position of the plate in the first passageway. A second fluid passageway communicates with the first and second fluid chambers through a circuitous path.