Hydraulic lash adjuster with combined reservoir extension and metering system

Claim 1

A hydraulic lash adjuster for valve gear of an internal combustion engine comprising: (a) a body having a blind bore formed therein; (b) plunger means slidably received in said body bore and defining, in cooperation with the blind end of said bore, a cavity, and a fluid reservoir; (c) a one way valve means positioned at one end of said plunger means permitting fluid flow from said reservoir to said cavity; (d) said body and plunger means including port means adapted for receiving fluid under pressure, said port means communicating with said reservoir intermediate the ends of said plunger means; (e) a cup shaped insert member disposed within said reservoir having an open end secured in fluid tight sealing engagement with the wall of the plunger means between said valve means and port means, the closed end of said insert member positioned in closely spaced relationship to the closed end of said plunger means and having at least one bore extending through the closed end of said insert member; (f) the closed end of said plunger means having a contact surface adapted to contact associated valve gear components and transmit periodically applied forces and a bleed orifice extending through the closed end of said plunger means and said contact surface, whereby fluid from said port means is communicated to both said insert bore and said plunger bore; (g) and, a fluid metering means associated with the closed end of said insert and with said bleed orifice to precisely meter the flow of fluid through said bleed orifice.