Caterpillar Inc.
Rocker arm assembly having a hydraulic lash adjuster

Abstract:

A method of retrofitting a rocker arm assembly for an engine includes removing a first rocker arm assembly from the engine such that a camshaft of the engine remains in the engine. The method also includes providing a second rocker arm assembly that includes a rocker shaft, a rocker arm, a pushrod, and a hydraulic lash adjuster. The rocker arm is connected to the rocker shaft such that the rocker arm can pivot relative to the rocker shaft. The rocker arm has a first end, a second end, and a first oil passage. The pushrod has a top end and a bottom end, in which the top end is connected to the second end of the rocker arm and the bottom end is configured for engaging a camshaft of the engine. The hydraulic lash adjuster includes a housing, a first body member, a second body member, a check valve, and a biasing member. The first body member is disposed in the housing such that a first radial clearance exists between an outer surface of the first body member and an inner surface of the housing. The first body member has a first bore and an opening in fluid communication with the first oil passage of the rocker arm. The second body member is disposed in the first bore of the first body member such that a second radial clearance exists between the inner surface of the first bore of the first body member and an outer surface of the second body member. The second radial clearance is less than the first radial clearance. The check valve is configured to allow oil to flow through the opening of the first body member when the check valve is in an open position and configured to prevent the flow of oil through the opening when the check valve is in the closed position. The biasing member is disposed in a second bore of the second body member. The method further includes inserting the second rocker arm assembly into the engine such that the bottom end of the pushrod engages the camshaft of the engine and the front end of the rocker arm engages a valve assembly of the engine.