Energy absorbing knee bolster

摘要

An apparatus (10) for helping to protect an occupant (28) of a vehicle (12) includes a knee bolster (20). An energy absorbing device (80) is interposed between the knee bolster (20) and the vehicle (12). The device (80) includes a field responsive fluid (84) having a viscosity that varies in response to an energy field acting on the fluid. The device (80) also includes at least one passage (134) through which the fluid (84) flows upon movement of the knee bolster (20) relative to the vehicle (12). The device (80) further includes means (150) for varying the viscosity of the fluid (84) to vary the flow rate through the at least one passage (134) and thereby vary the resistance to movement of the knee bolster (20) relative to the vehicle (12).