Patent ID: 7644693

Claim:
A hydraulic lash adjuster adapted to be disposed within a blind bore having a bottom and defined in an internal combustion engine, the lash adjuster comprising: a body configured to be disposed within said bore defined in said engine, the body defining a generally cylindrical body bore that extends over the entire axial length of the body, and a fluid port in communication with a source of fluid pressure; a plunger assembly including a plunger member slidingly received within the body bore, and cooperating therewith to define a pressure chamber, the plunger assembly including a reservoir chamber in fluid communication with the fluid port; biasing means normally configured to urge the plunger assembly outward of the body bore, the plunger assembly including a portion adapted for engagement with an adjacent surface of a valve train component; and a generally cylindrical member disposed within a lower end of the body bore such that substantially the entire cylindrical member is provided within the body bore and the cylindrical member is adjacent a portion of said bore; wherein the biasing means includes a lower end thereof connected or seated, relative to the cylindrical member, the lower end of the biasing means being in a substantially fixed positional relationship with said bottom of said bore; the plunger assembly includes a check valve operable to control fluid communication between the reservoir chamber and the pressure chamber in response to the pressure difference therebetween; and the body bore and one of the plunger member and the cylindrical member cooperate to define a leakdown clearance permitting fluid communication from the pressure chamber to the reservoir chamber in response to movement of the plunger assembly inward of the body bore.