| 摘要 |
<p>A bucket tappet (10) is provided for direct-acting valve gear having a molded body portion (46) formed of a lightweight material, preferably plastic, having a thermal expansion suitable for use in an aluminium engine head. The body of the tappet includes a tubular wall (48), an inner tubular hub (52), and a transverse end wall (50) joining and supporting the hub within the outer tubular wall. The body of the tappet has a cam face member (54) formed of hardened material, preferably steel or iron-based, embedded therein for providing a cam contacting surface (22). A hydraulic lash adjusting piston/plunger assembly (64) formed of steel is received within the tubular hub. Leakdown control surfaces (70) within the lash adjuster are formed on the mating interfaces between the steel piston (72) and plunger (66).</p> |
