In valve systems for automotive vehicles, it is common to provide a hydraulic lash compensating element which is installed in a rocker arm, for example, as shown in U.S. Pat. No. 2,036,936. In such a construction, a foot section with a spherical cavity contacts a spherical protrusion of the lash element housing. This translates the relative axial movement of the push rod into the rotational movement of the rocker arm. In this patent, the foot section is secured by pressing a cylindrical section of the foot into a cavity in the push rod. (FIG. 1)
In some designs no separate foot section is used and the spherical end of the lash element housing is in direct contact with the engine valve. This is shown in U.S. Pat. No. 4,502,428. Such a design may have excessive contact stress between the lash element and the valve. (FIG. 2)
In other designs, the foot section has no external retaining device. It is simply held in place by valve spring preload pressure. Assembly of the rocker arm and lash element into the engine is very difficult with this type of design. In addition, this also forces the engine manufacture to inventory additional components. See U.S. Pat. No. 4,708,103 (FIG. 2).
In other designs the foot is attached to the valve stem. A flange on the foot engages a groove on the valve stem as shown in U.S. Pat. No. 4,570,582. This approach requires additional machining of the valve stem. (FIG. 4)
In another method described in U.S. Pat. No. 4,708,103, a retainer is attached to the lash element housing. It is roughly cylindrical in shape and has an inward flange on one end for retaining of the foot section but allowing relative rotation of the foot to the spherical protrusion of the housing.
Among the objectives of the present invention are to provide a hydraulic lash compensating element assembly which overcomes the deficiencies in the art; which minimizes stress between the lash element and the valve; which is easier to assemble; which reduces the inventory of component parts; which requires less machining; and which results in greater efficiency of the engine valve train.
USPTO Backgrounds
USPTO Backgrounds