Hydraulic support element with a ring filter

Abstract

A hydraulic support element for a variable valve train of an internal combustion engine, which has a cylindrical pot-shaped housing and a hollow cylindrical piston guided for movement in this housing and whose inner end is supported by a compression spring on the base wall of the housing. The outer end extends past the housing and is formed as a hemispherical bearing head. The interior is divided into an inner supply pressure space and an outer switching pressure space that are connected by inlet openings in the cylindrical side walls of the housing and the piston with a cylinder head side supply pressure line and by a non-return valve to a high-pressure space enclosed between the inner end of the piston and the base wall of the housing, or to a cylinder head side switching pressure line and also by a central hole formed in the bearing head to a rocker arm side switching pressure channel. To prevent the entry of harmful particles into the supply pressure space and/or the switching pressure space of the piston, the piston has a ring-shaped recess in its cylindrical side wall in the area of the inlet openings on the outside in the radial direction, and a filter element constructed as a ring filter is inserted into the ring-shaped recess of the piston with an axial positive-fit connection.