VALVE TRAIN SYSTEM DRIVE DEVICE FOR AN INTERNAL COMBUSTION ENGINE, AND ENGINE INCORPORATING SAME

摘要

In an internal combustion engine having an idle gear that transmits power received from a crankshaft to valve train systems, an idle shaft that rotatably supports the idle gear, and an outer cover that covers a crankcase from a lateral side, a valve train system drive mechanism includes a crankcase-side boss part is formed on a sidewall of the crankcase, which supports one end of the idle shaft. The drive mechanism also includes a case-cover-side boss part that is formed on the outer cover and supports the other end of the idle shaft. A cover-side joint part and a shaft-side joint part are formed at the case-cover-side boss part and the other end of the idle shaft, respectively, and engagement of the joint parts with each other precludes the idle shaft from rotating.

主权项

1. In an engine having a crankcase and a crankshaft provided in the crankcase, and having a valve train system and an idle gear that transmits power from the crankshaft to the valve train system, the engine further having an idle shaft that is provided in parallel to the crankshaft and which rotatably supports the idle gear thereon, and a case cover that covers a portion of the crankcase, the improvement comprising a valve train system drive device comprising:
a crankcase-side boss part formed on a wall of the crankcase for supporting a first end of the idle shaft; a case-cover-side boss part formed inside the case cover for supporting a second end of the idle shaft; wherein joint parts, that are configured to selectively engage with each other, are formed at the case-cover-side boss part and at the second end of the idle shaft, respectively, and wherein engagement of the joint parts with each other precludes the idle shaft from rotating.