| 摘要 |
A valve stem seal for an intake or exhaust valve in an internal combustion engine where the seal allows a metered amount of oil to run down the valve stem for lubrication of the stem in its valve guide. The seal is formed of a relatively rigid valve seal body having a cylindrical wall or skirt engaging the valve guide boss and an upper radially inwardly offset cylindrical wall of a smaller diameter with a radially inwardly extending flange having metering grooves on the upper and lower surfaces thereof, and a resilient insert or collar is positioned on the flange to sealingly engage the reciprocating valve stem; the motion of the collar during reciprocation of the valve stem providing a pumping action through the metering grooves.
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