Method and apparatus for an adjustable damper
A system for controlling vehicle motion is described. The system includes: a first set of sensors coupled with a vehicle, the first set of sensors configured for sensing the vehicle motion; and a vehicle suspension damper coupled with the first set of sensors, the vehicle suspension damper configured for adjusting a damping force therein, the vehicle suspension damper comprising: a primary valve; a pilot valve assembly coupled with the primary valve, the pilot valve assembly configured for metering a flow of fluid to the primary valve, in response to at least the sensing; and an orifice block coupled with the primary valve and comprising a control orifice there through, the control orifice configured for operating cooperatively with the pilot valve assembly in the metering the flow of fluid to the primary valve.
1. A vehicle suspension damper comprising:
a damping chamber containing a damping fluid, and a piston and a piston rod moveable in a damping cylinder;
a valve for controlling movement of said damping fluid in compression and/or rebound of said vehicle suspension damper, said valve comprising:
a primary valve including a primary valve member, said primary valve member resisting flow of said damping fluid along a first fluid flow path from a first side of said valve to a second side of said valve;
a first pressure reducing means and a second pressure reducing means disposed in a second fluid flow path between said first side of said valve and said second side of said valve;
wherein a surface of said primary valve member is exposed to said damping fluid in said second fluid flow path between said first pressure reducing means and second pressure reducing means;
said valve configured such that, during compression or rebound of said vehicle suspension damper, said damping fluid is urged to flow through said first fluid flow path at a first fluid pressure resisted by said primary valve member, and pressure of said damping fluid in said second fluid flow path is reduced by said first pressure reducing means and said second pressure reducing means to a second fluid pressure lower than said first fluid pressure; and
said second fluid pressure acts on said surface of said primary valve member such that said primary valve member increases resistance to flow of said damping fluid along said first fluid flow path, and;
a diffuser disposed in said second fluid flow path between said first pressure reducing means and said second pressure reducing means, said diffuser disrupting substantially linear flow of said damping fluid flow in said second fluid flow path, wherein said diffuser further comprises:
a plug having at least one fluid flow port, said fluid flow port configured to change a direction of said substantially linear flow of said damping fluid.
2. The vehicle suspension damper of claim 1 further comprising:
a first area of said primary valve member, said first fluid pressure acting over said first area of said primary valve member to urge said primary valve member open;
a second area of said primary valve member, said second fluid pressure acting over said second area of said primary valve member to urge said primary valve member closed; and
wherein a ratio of said first area of said primary valve member to said second area of said primary valve member determines how much resistance is provided by said primary valve member and thereby determines damping characteristics of said vehicle suspension damper.
3. The vehicle suspension damper of claim 2 wherein:
said second area of said primary valve member is smaller than said first area of said primary valve member.
4. The vehicle suspension damper of claim 3 wherein:
said second area of said primary valve member is approximately 60% than said first area of said primary valve member.
5. The vehicle suspension damper of claim 1 further comprising:
an exterior surface of said primary valve member, said exterior surface of said primary valve member exposed to said damping fluid on said second side of said valve; and
an interior surface of said primary valve member, said interior surface of said primary valve member exposed to said damping fluid in said second fluid flow path.
6. The vehicle suspension damper of claim 1 wherein:
said first pressure reducing means is configured to provide a bleed for said damping fluid at low compression or rebound velocities.
7. The vehicle suspension damper of claim 1 wherein:
said first pressure reducing means is configured to provide a reduction in pressure of said damping fluid pressure at high compression or high rebound velocities.
8. The vehicle suspension damper of claim 7 wherein:
said reduction in said pressure of said damping fluid is directly proportional to a velocity of a flow of said damping fluid through said first pressure reducing means such that hydraulic locking of said primary valve member is inhibited.
9. The vehicle suspension damper of claim 1 wherein said first pressure reducing means further comprises a feature selected from the group consisting of: an orifice, a diffuser, a labyrinth, and a screw thread.
10. The vehicle suspension damper of claim 1 wherein said second pressure reducing means is adjustable wherein adjustment of said second pressure reducing means adjusts said second fluid pressure, and generates a corresponding change in resistance by said primary valve member to flow of said damping fluid flow along said first fluid flow path.
11. The vehicle suspension damper of claim 10 wherein said second pressure reducing means is adjustable via a feature selected from the group consisting of: a manual adjuster, an automatic adjuster controllable by a computing device.
12. The vehicle suspension damper of claim 1 wherein said second pressure reducing means further comprises:
a pilot valve controllable by an electro-mechanical device.
13. The vehicle suspension damper of claim 1 wherein said second pressure reducing means further comprises a feature selected from the group consisting of: a spool valve controlled by a magnetic latching solenoid, a needle positionable relative to a seat, a vane valve, a solenoid valve, and a moveable screw.
14. The vehicle suspension damper of claim 1 wherein:
said primary valve member acts directly against said first fluid pressure; and
when said second pressure reducing means is adjusted to reduce said second fluid pressure, said primary valve member is moved by said first fluid pressure to increase flow of said damping fluid through said first fluid flow path.
15. The vehicle suspension damper of claim 1 wherein:
said first pressure reducing means is configured to produce turbulent flow of said damping fluid downstream of said first pressure reducing means.
16. The vehicle suspension damper of claim 1 wherein said diffuser causes a change in velocity of said substantially linear flow of said damping fluid.
17. The vehicle suspension damper of claim 1 wherein said diffuser further comprises:
a pin having a longitudinal axis oriented substantially perpendicular to a direction of said substantially linear flow of said damping fluid.
18. The vehicle suspension damper of claim 1 wherein said primary valve member further comprises:
an annular piston, said annular piston axially moveable along a valve body.
19. The vehicle suspension damper of claim 1 wherein said primary valve member further comprises:
a valve body including a fluid port; and
an annular piston, said annular piston axially moveable along said valve body, said fluid port of said valve body providing fluid communication between an interior of said valve body interior and an interior of said annular piston.
20. The vehicle suspension damper of claim 19 wherein said valve body further comprises:
said first pressure reducing means and said second pressure reducing means, said interior of said valve body comprises a pilot pressure chamber hydraulically coupled between said first pressure reducing means and said second pressure reducing means, said pilot pressure chamber in fluid communication with said annular piston interior via said fluid port.
21. The vehicle suspension damper of claim 1 further comprising:
a shim for controlling flow of said damping fluid along said first fluid flow path, said primary valve member configured to apply a variable force to said shim, such that resistance to flow of said damping fluid along said first fluid flow path is a sum of resistance to flow of said damping fluid provided by said shim and resistance to flow of said damping fluid provided by said primary valve member.