Suzuki Motor Corporation

Koji Mori

Koichi Tanaka

Kunio Arase

Kohei Kato

Makoto Nagao

Shuichi Imanari

The present invention can achieve a variable valve mechanism having a simple and compact configuration. A variable valve mechanism changes an opening/closing timing of an intake valve or an exhaust valve in response to an engine rotation speed. The variable valve mechanism includes: a cam sprocket which rotates in response to a rotation of a crank shaft; an intake cam shaft which is integrated with an intake cam; an exhaust cam shaft which is integrated with an exhaust cam; and a governor flange that transmits a rotation of the cam sprocket to the intake cam shaft and the exhaust cam shaft. The intake cam shaft and the exhaust cam shaft are formed so that the other cam shaft is inserted through one cam shaft to be relatively rotatable. The governor flange is provided to rotate along with the intake cam shaft and rotates relative to the cam sprocket under a predetermined condition.

Variable valve mechanism, engine, and automatic two-wheeled vehicle

A bearing holding portion supporting a crankshaft in a manner to rotate freely via a bearing and fittingly holding the bearing is formed in a crankcase. A second cross section passing through a crankshaft axis line and along an orthogonal direction to a cylinder axis line is set to have a larger cross-sectional area than a first cross section passing through the crankshaft axis line and along a direction of the cylinder axis line in the bearing holding portion.

Growing community of inventors

Hamamatsu, Japan

Koji Mori