Piston with an integral electrically operated adjustment valve for a hydraulic vibration damper

A piston for a vibration damper that has a cylinder and a piston assembly with a rod extending out of the cylinder, the piston assembly includes a piston slidably received within the cylinder thereby defining a compression chamber and a rebound chamber each having fluid under pressure therein, the piston comprising:

• a piston body that has a bore with a valve seat therein through which fluid flows between the compression and rebound chambers;
• a poppet en a in and disengaging the valve seat;
• a pilot valve body within the bore of the piston body and having a pilot bore;
• a pressure cavity in the piston body;
• a pilot chamber on a side of the poppet remote from the valve seat, and formed between the pilot valve body and the poppet;
• a pilot valve member varying an amount of fluid flow between the pilot chamber and the pressure cavity, wherein the pilot valve member comprises a pilot spool moveably received within the pilot bore;
• a first logic arrangement which applies a greater one of the pressure in the compression and the pressure in the rebound chamber to the pilot chamber;
• a second logic arrangement which opens the pressure cavity to whichever of the compression and rebound chambers has a lower pressure than pressure in the pressure cavity;
• and
• an electrically operated actuator that moves the pilot valve member.

A piston for a vibration damper that has a cylinder and a piston assembly with a rod extending out of the cylinder, the piston assembly includes a piston slidably received within the cylinder thereby defining a compression chamber and a rebound chamber each having fluid under pressure therein, the piston comprising:

• a piston body that has a bore with a valve seat therein through which fluid flows between the compression and rebound chambers;
• a poppet engaging and disenga in valve seat;
• a pilot chamber on a side of the poppet remote from the valve seat;
• a first logic arrangement which applies a greater one of the pressure in the compression and the pressure in the rebound chamber to the pilot chamber;
• a pressure cavity in the piston body;
• a pilot valve member varying an amount of fluid flow between the pilot chamber and the pressure cavity;
• a second logic arrangement which opens the pressure cavity to whichever of the compression and rebound chambers has a lower pressure than pressure in the pressure cavity;
• a piston cavity between the poppet and the piston body,
• a bleed orifice providing a fluid path between the piston cavity and the pressure cavity;
• and
• an electrically operated actuator that moves the pilot valve member.

A piston for a vibration damper that has a cylinder and a piston assembly with a rod extending out of the cylinder, the piston assembly including a piston slidably received within the cylinder thereby defining a compression chamber and a rebound chamber, the piston comprising:

• a piston body having a bore with separate openings in fluid communication with the compression chamber and the rebound chamber and a valve seat within the bore between those openings;
• a poppet moveable within the bore to engage and disengage the valve seat and having a pilot chamber on a side of the poppet remote from the valve seat;
• a first check valve through which fluid flows from the compression chamber to the pilot chamber;
• a second check valve through which fluid flows from the rebound chamber to the pilot chamber;
• a pilot bore into which a first fluid passage opens from the pilot chamber and into which a second fluid passage opens;
• a third check valve through which fluid flows from the second fluid passage to the compression chamber;
• a fourth check valve through which fluid flows from the second fluid passage to the rebound chamber;
• a pilot valve element received within the pilot bore and selectively controlling flow of fluid between the first and second fluid passages;
• and
• an electrically operated actuator that moves the pilot valve element.