| 摘要 |
A valve guide (14) for guiding a stem (13) of a headed poppet valve (11) for slidable movement in an internal combustion engine has an inner bearing surface (17) of generally cylindrical shape but a groove (18) which is cut spirally into that surface extends radially outwardly therefrom and provides a lubricant passage which extends for at least part o the length of the bearing surface (17). The cross-sectional shape of the spiral groove (18) is characterized by a lower groove portion (21) which is substantially at right angles to the stem (13) and functions to scrape lubricant off the stem (13) and as he stem (13) moves downwardly in the valve opening direction, but the upper surface portion (22) of the groove (18) back into clearance space between the valve stem (13) and guide (14).
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