| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a valve gear which can suppress an increase of friction resistance at a journal part caused by press-fitting of a cam shaft into a boss part of a valve timing variable mechanism.SOLUTION: A valve gear comprises a cam shaft 1 and a valve timing variable mechanism 2. In the valve timing variable mechanism 2, a rotor 4 fixed with the cam shaft 1 is accommodated in a housing 3 which rotates synchronously with a crank shaft, and the valve timing variable mechanism 2 changes the opening/closing timing of an engine valve by relatively rotating the rotor 4 with respect to the housing 3. The cam shaft 1 is press-fitted into boss part 8 located at a tip of a shaft part 7 arranged in a center of the rotor 4, and a journal part 11 which is arranged continuously to the boss part 8 is rotatably supported by a cylinder head 12 and a cam cap 13 of an internal combustion engine. In the valve gear, rigidity of the boss part 8 at the shaft part 7 is set lower than rigidity of the journal part 11.</p> |
