Electronic damper control
Generally described, aspects of the disclosed subject matter are directed to electronically controlled dampers having shimmed pistons. In accordance with aspects of the present disclosure, the dampers generally include a shaft having a piston with compression and rebound valves extending therethrough. For further damper tuning and adjustment, a fluid bypass assembly permits damping fluid to bypass the piston during operation. The fluid bypass assembly may include a metering pin for manual adjustment of the fluid bypass, and a control valve for electronic adjustment of the fluid bypass. In this regard, the control valve may be controlled automatically, manually, or a combination thereof.
1. An electronically controlled damper, comprising:
a damper body defining a chamber for housing a damping fluid and having a first mounting portion at a distal end and a shaft aperture at a proximal end;
an elongate shaft slidingly extending through the shaft aperture, the elongate shaft having a distal portion within the chamber and a proximal portion external to the chamber;
a piston disposed at a distal end of the elongate shaft, the piston defining a first chamber portion at the distal end of the chamber and a second chamber portion at the proximal end of the chamber, the piston having a damping valve and configured to sealingly translate along the chamber; and
a fluid bypass assembly external to the chamber at a proximal end of the elongate shaft, the fluid bypass assembly comprising:
a second mounting portion;
a first reservoir for the damping fluid in fluid communication with the first chamber portion;
a second reservoir for the damping fluid in fluid communication with the second chamber portion; and
a control valve having a plunger positioned between the first and second reservoirs and configured to selectively reciprocate from a closed position when de-energized, where damping fluid is prevented from flowing between the first and second reservoirs, to an open position when energized, where damping fluid is permitted to flow from the second reservoir to the first reservoir during a rebound stroke of the damper,
wherein the plunger is positioned such that pressure of the damping fluid in the second reservoir exerts a force to bias the plunger toward the closed position during the rebound stroke of the damper.
2. The electronically controlled damper of claim 1 , further comprising a biasing member applying a return force to bias the plunger toward the closed position, the biasing member configured to permit the plunger to retract to the open position at a threshold positive pressure differential of the damping fluid between the first and second reservoirs during a compression stroke of the damper.
3. The electronically controlled damper of claim 1 , further comprising a metering pin positioned between the first and second reservoirs to adjustably allow damping fluid to flow therebetween.
4. The electronically controlled damper of claim 3 , wherein the metering pin has a tapered helical cut configured to variably adjust damping fluid flow.
5. The electronically controlled damper of claim 1 , wherein the first reservoir is in fluid communication with the first chamber portion through a passageway in the elongate shaft.
6. The electronically controlled damper of claim 5 , further comprising a check valve coupled to the elongate shaft adjacent to the piston, the check valve configured to allow damping fluid to flow out of the passageway into the first chamber during the rebound stroke of the damper, and to prevent damping fluid flow into the passageway from the first chamber during a compression stroke of the damper.
7. The electronically controlled damper of claim 5 , wherein the second reservoir is in fluid communication with the second chamber portion through a radial port and an annular jacket surrounding the passageway in the elongate shaft.
8. The electronically controlled damper of claim 7 , further comprising a pilot piston slidingly disposed in the passageway and configured to selectively permit damping fluid flow from the passageway to the second chamber during the compression stroke of the damper.
9. The electronically controlled damper of claim 8 , wherein the damping fluid is directed through a secondary damping valve adjacent to the piston in the second chamber when the pilot piston is in a position to permit damping fluid flow from the passageway to the second chamber during the compression stroke of the damper.
10. An electronically controlled piston bypass system for a damper, comprising:
an elongate shaft having a damping piston disposed at a distal end of the elongate shaft, the piston having a first side facing away from the elongate shaft, a second side opposite the first side, and a damping valve; and
a fluid bypass assembly disposed at a proximal end of the elongate shaft, comprising:
a first reservoir for receiving damping fluid in fluid communication with a passageway in the elongate shaft having an axial aperture opening toward the first side of the piston;
a second reservoir for receiving damping fluid in fluid communication with an annular jacket surrounding the passageway and having a radial aperture through the elongate shaft; and
a control valve having a plunger positioned between the first and second reservoirs and configured to selectively reciprocate from a closed position when de-energized, where damping fluid is prevented from flowing between the first and second reservoirs, to an open position when energized, where damping fluid is permitted to flow from the second reservoir to the first reservoir during a rebound stroke of the damper,
wherein the plunger is positioned such that pressure of the damping fluid in the second reservoir exerts a force to bias the plunger to the closed position during the rebound stroke of the damper.
11. The electronically controlled piston bypass system for a damper of claim 10 , further comprising a biasing member applying a return force to bias the plunger to the closed position, the biasing member configured to permit the plunger to retract to the open position at a threshold positive pressure differential between the first and second reservoirs during a compression stroke of the damper.
12. The electronically controlled piston bypass system for a damper of claim 10 , further comprising a metering pin positioned between the first and second reservoirs to adjustably allow damping fluid to flow therebetween.
13. The electronically controlled piston bypass system for a damper of claim 12 , wherein the metering pin has a tapered helical cut configured to variably adjust damping fluid flow.
14. The electronically controlled piston bypass system for a damper of claim 10 , further comprising a check valve coupled to the elongate shaft adjacent to the piston, the check valve configured to allow damping fluid to flow out of the passageway through the axial aperture during the rebound stroke of the damper, and to prevent fluid flow into the passageway through the axial aperture during a compression stroke of the damper.
15. The electronically controlled damper of claim 10 , further comprising a pilot piston slidingly disposed in the passageway and configured to selectively permit damping fluid flow from the passageway to the second chamber during the compression stroke of the damper.
16. The electronically controlled damper of claim 15 , wherein the damping fluid is directed through a secondary damping valve adjacent to the piston in the second chamber when the pilot piston is in a position to permit damping fluid flow from the passageway to the second chamber during the compression stroke of the damper.