Patent ID: 8317172

Claim:
A multistage jounce bumper for responding to a jounce force in stages, comprising: a jounce bumper cushion comprising a resilient material; and a hydraulic jounce bumper connected to said jounce bumper cushion, said hydraulic jounce bumper comprising: a cylinder and movable piston combination collectively defining an hydraulic fluid filled cavity; a communicating hydraulic fluid reservoir fluidically connected to said hydraulic fluid filled cavity; a control valve selectively metering hydraulic fluid flow between said hydraulic fluid filled cavity and said hydraulic fluid reservoir, wherein the selective metering by said control valve ranges between a fully closed state whereat the flow is prevented and an open state whereat the flow is enabled; and a source of pressurization of hydraulic fluid within said hydraulic fluid reservoir which provides an initial predetermined pressure of the hydraulic fluid in said hydraulic fluid cavity; wherein a first stage of response to a jounce force during a jounce comprises: the jounce force causing said jounce bumper cushion to become resiliently compressed a predetermined amount; and said control valve being in said fully closed state such that metering of hydraulic fluid flow between said hydraulic fluid filled cavity and said hydraulic fluid reservoir is prevented; wherein a second stage of response to the jounce force during the jounce comprises said control valve being in said open state such that hydraulic fluid in said hydraulic fluid reservoir is metered flowably into said hydraulic fluid reservoir as said piston moves into said cylinder so as to thereby absorb energy of the jounce; and wherein said control valve is tuned such that during the jounce said first stage response precedes said second stage response.