| 摘要 |
<p>An internal combustion engine has a sprocket driven by a timing chain in synchronization with the engine rotation and a camshaft for driving intake or exhaust valves. A valve timing control device of the engine comprises a first rotating member on which the sprocket is integrally formed; a second rotating member capable of making a relative rotation to the first rotating member and rotated together with the camshaft; a plurality of working fluid chambers defined between the first and second rotating members; and a charging/discharging means for charging and discharging a working fluid to and from the working fluid chambers to induce the relative rotation between the first and second rotating members. The sprocket and at least a base part of the first rotating member on which the sprocket is integrally formed are constructed of a porous metal member. Thus, the working fluid led into the working fluid chambers is allowed to penetrate into the sprocket through the base part thereby to bring about a sufficient lubrication of a portion where the sprocket and the timing chain are meshed. The porous metal member may be a sintered metal.</p> |
