| 摘要 |
A valve timing device for an internal combustion engine includes a hub with an internal helical groove which engages a tracking post extending from a cylindrical surface of a crankshaft. A locking cap is placed at the outer end of the crankshaft spaced apart from the hub with a compression spring wrapped about the crankshaft between the hub and the locking cap. A sprocket is keyed onto the hub and trained about a chain which is drivingly trained about a conventional camshaft. As the crankshaft speed is increased, inertial loads of the camshaft causes the sprocket and hub to rotate relative to the crankshaft which axially moves the hub a predetermined amount along the crankshaft to compress the spring until the resilient forces of the spring counterbalances the inertia forces of the camshaft. As the hub is angularly positioned, the camshaft becomes angularly retarded relative to the crankshaft such that the valve operation is delayed with respect to the piston operation as the engine speed increases. |
