| 摘要 |
PURPOSE:To eliminate the necessity for a conventional valve returning spring and reduce a load applied to a cam shaft, by providing an outer frame in a cam and opening and closing a valve through a lifting member by rotation of the outer frame actuated interlocking to the cam, in the case of the intake and exhaust valve in a four-cycle internal-combustion engine. CONSTITUTION:An engine inserts a valve 3 from inside a cylinder head part 4 further mounts a case-shaped nut 9 and a coil spring 11 to an upper part of the valve 3. When the valve 3 is opened, a cam 1 moves downward a push rod 8, and its bottom end part 6 presses an upper end part 12 of the valve 3. On the contrary, when the valve 3 is returned, the engine, pulling an upper end part 5 of the push rod 8 by an outer frame 2 provided in outside the cam 1, lifts the upper end part 12 of the valve 3 to be moved upward by the bottom end part 6 of the push rod 8 and the case-shaped nut 9 connected with the push rod 8. In this way, the engine, which can eliminate the necessity for a conventional valve returning spring, causes no repulsive force of the valve returning spring to be applied to the cam 1, and performance of the engine can be improved by reducing a load applied to a cam shaft. |
