Metering valve for ball plunger or pushrod socket

A hydraulic lash adjuster for an internal combustion engine, said lash adjuster comprising a body defining a bore formed therein;

• a plunger assembly slidingly received within said bore, and cooperating therewith to define a pressure chamber;
• a fluid chamber disposed within said plunger assembly, and being in communication with a source of fluid;
• one of said body and said plunger assembly including an external surface adapted for engagement with another member;
• said one of said body and said plunger assembly defining an axially-extending opening extending from said fluid chamber to said external surface;
• and a metering pin disposed in said opening, and axially moveable therein;
• characterized by:
• (a) said metering pin and said opening cooperating to define means limiting downward movement of said metering pin toward said fluid chamber, and operable to prevent fluid flow from outside of said lash adjuster, past said metering pin and into said fluid chamber;
• (b) said metering pin including a stop portion larger than said axially-extending opening, to limit upward movement of said metering pin in response to pressure in said fluid chamber;
• and,
• (c) said axially-extending opening and said metering pin cooperating to define a metering passage having a predetermined metering flow area when said metering pin is in its upwardmost axial position to permit communication of fluid from said fluid chamber to said external surface said metering passage comprising a groove disposed on at least one of the exterior of said metering pin and the surface of said axially extending opening.