| 摘要 |
PURPOSE:To equalize each dimension of a pair of rocker arms and increase the diameter of an intake valve by arranging each valve shaft of an intake valve and an exhaust valve and the center of a cam shaft at specific positions, in an engine equipped with a rocker-arm system overhead-cam type tappet mechanism. CONSTITUTION:In an engine, a pair of rocker arms 14 and 15 are swung through a tappet cam 11 by the revolution of a cam shaft 10 installed on a cylinder head 3, being interlocked with a crank shaft, and an intake valve 6 and an exhaust valve 7 are opened and closed in a prescribed timing through each valve shaft 6a, 7a. In this case, the cam shaft 10 is arranged by positioning in offset the center C1 of the cam shaft crossing at a right angle with a cylinder deck surface, by a proper distance l to the exhaust valve 7 side relative to the center C2 of a cylinder, and each valve shaft 6a, 7a is tilted symmetrically relative to the center C1 of the cam shaft. Thus, each dimension of both rocker arms 14 and 15 is made equal, and the diameter of the intake valve 6 is increased by twice the distance l, and the productivity and the intake efficiency are increased. |
