| 摘要 |
PURPOSE:To reduce the size and cost of a cylinder head, by providing sprockets on cam shafts for an intake and an exhaust valves so that the sprockets are partially juxtaposed in the axial direction of the shafts and by engaging twin chains with the sprockets to drive them. CONSTITUTION:In an engine of double overhead cam type, the distance between a first cam shaft 2 for an intake valve 1 and a second cam shaft 4 for an exhaust valve 3 is reduced and sprockets 5, 6 on the cam shafts are partially juxtaposed. Twin sprockets 8 are secured on a crankshaft 7. Twin chains 9 are engaged with eh sprockets 8 and the sprockets 5, 6 respectively. According to this constitution, by cylinder head of the engine is made compact. Since the cam shafts 2, 4 are driven through the twin chains 9, the intake valve 1 and the exhaust valve 3 are kept from becoming asynchronous to each other in opening and closing. |
