# US 2014/0190778 A1 · Inerting damper with regressive characteristics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190778 A1 - Document ID: US20140190778A1 - Status: Published application - Kind: A1 - Application number: 14/151,276 - Filed: 2014-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Applicants: Penske Racing Shocks - Inventors: Bill J. Gartner - Web page: https://patentgrep.com/patent/US20140190778A1 ## CPC - F16F 9/46: allowing control from a distance {, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall (attachment of valve units to cylinders F16F9/325)} - F16F 9/504: Inertia {, i.e. acceleration,}-sensitive means - F16F 7/1034: {of movement of a liquid} - F16F 9/065: {Expansion chamber provided on the upper or lower end of a damper, separately there from or laterally on the damper} - F16F 9/182: {comprising a hollow piston rod} - F16F 9/3214: {of pistons (F16F9/0227 and F16F9/36 take precedence; throttling passages in or on piston body F16F9/3405)} - F16F 9/3405: {Throttling passages in or on piston body, e.g. slots (F16F9/344, F16F9/3481 take precedence)} - F16F 9/3488: {characterised by features intended to affect valve bias or pre-stress} - F16F 9/50: Special means providing automatic damping adjustment, {i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs}(F16F9/53 takes precedence); {Special means providing self-adjustment of spring characteristics} - F16F 9/512: Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} - F16F 9/5126: {Piston, or piston-like valve elements (F16F9/504 takes precedence)} - F16F 9/516: resulting in the damping effects during contraction being different from the damping effects during extension {, i.e. responsive to the direction of movement (F16F9/504 takes precedence)} - F16F 2222/08: Inertia - F16F 2228/12: degressive - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION ## Abstract Apparatus and methods for damping a vehicle suspension. Various embodiments of dampers in hydraulic flowpaths are adapted and configured to provide shock absorber reactive forces resulting more from the pressure drop needed to overcome the inertia of the hydraulic fluid. Further, various embodiments include valving that provides a regressive characteristic to the shock absorber reactive load characteristics. ## Claims ### Claim 1 A method for hydraulically damping a suspension of a vehicle, comprising: providing a shock absorber including a piston attached to a rod and slidable within a chamber and sealingly dividing the chamber into first and second internal compartments, the rod being attached to one of the vehicle or the suspension; providing an inertial flowpath for hydraulic fluid adapted and configured to have substantially more pressure drop required to overcome the inertia of accelerating a flow of hydraulic fluid through the flowpath than the pressure drop required to overcome the viscous drag of flowing the same flow of hydraulic fluid through the flowpath; providing a valve with a first fluid port and a second fluid port and capable of switching from a first more viscously restrictive flowpath for hydraulic fluid between the first port and second port and to a second less viscously restrictive flowpath for hydraulic fluid between the first port and second port; pumping hydraulic fluid by the piston from one of the internal compartments through the inertial flowpath; pumping hydraulic fluid by the piston from the one internal compartment through the first restrictive flowpath of the valve if the fluid pressure at the valve first fluid port is less than a predetermined value or through the second restrictive flowpath if the fluid pressure at the valve first fluid port is greater than the predetermined value; and returning the pumped hydraulic fluid to the other internal compartment. ### Claim 2 (depends on 1) The method of claim 1 wherein the valve includes a valve member movable between a first position that establishes the first flowpath and a second position that establishes the second flowpath, and a spring that biases the valve member to the first position. ### Claim 3 (depends on 1) The method of claim 1 wherein the first restrictive flowpath and the second restrictive flowpath share a flow orifice. ### Claim 4 (depends on 1) The method of claim 1 wherein the shock absorber includes a gas reservoir and the valve is located in the gas reservoir. ### Claim 5 (depends on 4) The method of claim 4 wherein one of the valve ports is in fluid communication with the inertial flowpath and the other of the valve ports is in fluid communication with an internal compartment. ### Claim 6 (depends on 4) The method of claim 4 wherein the valve includes an adjuster for changing the predetermined value of fluid pressure. ### Claim 7 (depends on 4) The method of claim 4 wherein the valve includes an adjuster for changing the flow characteristics of one of the first flowpath or the second flowpath. ### Claim 8 (depends on 1) The method of claim 1 wherein the inertial flowpath is in series with the first restrictive flowpath and in series with the second restrictive flowpath. ### Claim 9 (depends on 8) The method of claim 8 wherein the valve is located in one of the first or second internal compartments. ### Claim 10 (depends on 1) The method of claim 1 wherein the inertial flowpath is in parallel with the first restrictive flowpath and in parallel with the second restrictive flowpath. ### Claim 11 (depends on 10) The method of claim 10 wherein the piston includes the valve. ### Claim 12 A method for hydraulically damping a vehicle suspension, comprising: providing a shock absorber operable in compression and rebound and including a piston attached to a rod and slidable within a cylinder, the cylinder being located within an enclosed housing, the rod being attached to one of the vehicle or the suspension and the housing being attached to the other of the vehicle or the suspension; providing a first hydraulic flowpath between the housing and the cylinder, one end of the first flowpath being in fluid communication with the one end of the cylinder and the other end of the first flowpath being in fluid communication with the other end of the cylinder, the first hydraulic flowpath being adapted and configured to provide substantially more inertial resistance to a flow of hydraulic fluid than the viscous resistance to the same flow of hydraulic fluid; providing a second hydraulic flowpath with the piston that provides fluid communication across the piston from the one end of the cylinder to the other end of the cylinder; flowing first hydraulic fluid through the first flowpath and not through the second flowpath when the piston stroking velocity is less than a predetermined value; applying a first corresponding reactive load by the shock absorber on the suspension during said first flowing; flowing second hydraulic fluid through the first flowpath and through the second flowpath in parallel when the piston stroking velocity is greater than the predetermined value; and applying a second corresponding reactive load by the shock absorber on the suspension during said second flowing, the second load being less than the first load. ### Claim 13 (depends on 12) The method of claim 12 wherein the first flowpath includes a plurality of bends that change the direction of the hydraulic fluid. ### Claim 14 (depends on 13) The method of claim 13 wherein at least a portion of the first flowpath includes a helically-shaped passageway. ### Claim 15 (depends on 14) The method of claim 14 wherein the helically shaped passageway wraps around the cylinder. ### Claim 16 (depends on 12) The method of claim 12 wherein the first flowpath curves circumferentially around the cylinder a plurality of revolutions, the first flowpath being adapted and configured to substantially increase the angular momentum of hydraulic fluid flowing therethrough. ### Claim 17 (depends on 12) The method of claim 12 wherein the piston is slidable along a travel distance from one end of the cylinder to the other end of the cylinder, and the first flowpath extends substantially the length of the travel distance. ### Claim 18 (depends on 12) The method of claim 12 wherein the first flowpath is adapted and configured such that during said first flowing and said second flowing the viscous pressure drop in the first flowpath is less than the corresponding pressure difference needed in the first flowpath to overcome the inertia of the hydraulic fluid. ### Claim 19 (depends on 12) The method of claim 12 wherein said first flowing is by stroking the piston in a direction, and said second flowing is by stroking the piston in the same direction. ### Claim 20 (depends on 19) The method of claim 19 wherein the direction is in compression of the shock absorber. ### Claim 21 (depends on 19) The method of claim 19 wherein the direction is in rebound of the shock absorber. ### Claim 22 (depends on 12) The method of claim 12 wherein the rod is a first rod and said providing includes a second rod attached to the piston and extending out of the cylinder. ### Claim 23 A method for hydraulically damping a vehicle suspension, comprising: providing a shock absorber operable in compression and rebound including a piston attached to a rod and slidable within a cylinder from one end of the cylinder to the other end of the cylinder, a housing having a pair of fluid ports and an internal flowpath therebetween, one end of the cylinder being in fluid communication with one port, a valve providing fluid communication from the other end of the cylinder to the other port of the housing with either of a first more restrictive valve flowpath or a second less restrictive valve flowpath, the rod being attached to one of the vehicle or the suspension; flowing first hydraulic fluid through the first valve flowpath and the internal flowpath when the piston stroking velocity is less than a predetermined value; applying a first corresponding reactive load by the shock absorber on the suspension during said first flowing; flowing second hydraulic fluid through the second valve flowpath and the internal flowpath when the piston stroking velocity is greater than the predetermined value; and applying a second corresponding reactive load by the shock absorber on the suspension during said second flowing, the second load being less than the first load. ### Claim 24 (depends on 23) The method of claim 23 wherein the valve is annular in shape and receives the rod through a central aperture. ### Claim 25 (depends on 24) The method of claim 24 wherein the valve is located within the cylinder. ### Claim 26 (depends on 24) The method of claim 24 wherein the valve is located outside of the cylinder. ### Claim 27 (depends on 24) The method of claim 24 wherein the valve is located within the housing. ### Claim 28 (depends on 23) The method of claim 23 wherein during said first flowing there is a first valve flowpath viscous pressure drop, during said second flowing there is a second valve flowpath viscous pressure drop, and the first drop is greater than the second drop. ### Claim 29 (depends on 28) The method of claim 28 wherein during said first flowing there is a first inertial pressure drop across the internal flowpath, during said second flowing there is a second inertial pressure drop across the internal flowpath, and the first drop is less than the second drop. ### Claim 30 (depends on 23) The method of claim 23 wherein the internal flowpath is adapted and configured such that during said first flowing and said second flowing the viscous pressure drop across the internal flowpath is less than the corresponding pressure difference needed across the internal flowpath to overcome the inertia of the hydraulic fluid flowing in the internal flowpath. ### Claim 31 (depends on 23) The method of claim 23 wherein the piston substantially blocks the flow of hydraulic fluid from one end of the cylinder to the other end of the cylinder. ### Claim 32 (depends on 23) The method of claim 23 wherein the piston includes at least one check valve permitting fluid flow across the piston. ### Claim 33 (depends on 23) The method of claim 23 wherein the valve includes an orifice and both the first flowpath and the second flowpath permit flow through the orifice. ### Claim 34 (depends on 23) The method of claim 23 wherein said first flowing is by stroking the piston in a direction, and said second flowing is by stroking the piston in the same direction.