| 摘要 |
PURPOSE:To obtain a valve-operating characteristic suited for operating conditions in a simple construction by rotating a rocker arm centering around the top of a valve stem and by setting a cam-sliding surface of the rocker to either high or low speed cam. CONSTITUTION:High- and low speed intake valve cams 11H, 11L and high- and low speed exhaust valve cams 12H, 12L are mounted to a cam shaft 10. Rocker arms 3, 4 are supported on a rocker shaft 5 with a spherical part 6 and a spherical connecting part 7. The sides of the rocker arms 3, 4 opposite to the cams are brought in contact with the tops of stems of an intake valve 1 and an exhaust valve. In accordance with the operating state of an engine, a three-way valve 20 is regulated by a controller 21, a hydraulic piston 16 operates, and the rocker shaft 5 shifts toward the shaft. The rocker arms 3, 4 rotate centering around the top of the valve stem, and the cam-sliding surface side is set to either high or low speed cam. Thus, a suitable valve-operating characteristic can be selected. |
