OVERHEAD CAM SHAFT TYPE FOUR-VALVE ENGINE

摘要

PURPOSE:To miniaturize an engine, by making a rocker arm independent at every valve, while molding a cam case solidly with a cylinder in one together with a cover, in case of such an engine that has each of plural suction and exhaust valves per cylinder. CONSTITUTION:Two suction valves 4 and exhaust valves each are installed in one combustion chamber 2 and driven by a cam shaft 10 installing each valve in a cam case 18 on top of the combustion chamber 2 via rocker arms 8 and 9. Each of shafts 8a and 9a of these rocker arms 8 and 9 is made up separately at every suction and exhaust valve whereby the cam case 15 is solidly unified with a cylinder head 1 together with a cover. According to this method, the space required for a bolt securing the cover of the cam case is no longer necessary, so that even in case an engine is of small piston displacement and even these rocker arms are made independent together with its shafts totaling four pieces, they are easy to be incorporated in the cam case 15, and, what is more, one rocker arm does not operate two valves at all so that this method may contribute to a distinct improvement in engine performance.