| 摘要 |
<p>A bearing supporting a crankshaft provided in a connecting rod comprises an overlay in contact with a throw, a metal layer on the outside of the overlay and a back metal on the outside of the metal layer. The hardness of the metal layer is lower than that of the back metal, and the thermal conductivity of the overlay is higher than that of the throw. The metal layer having a lower hardness than the back metal improves the fit of the bearing with the throw, and sharp increase of frictional losses and rise of lubricating oil temperature at high engine rotation speeds are thereby prevented. The overlay having a high thermal conductivity absorbs heat from the minimum thickness oil film formed between the inner surface region of the throw and the bearing, and after the bearing has passed through the minimum thickness oil film, the absorbed heat is again discharged to the lubricating oil. In this way, temperature rise of the throw in the vicinity of the minimum thickness oil film is suppressed, decreased viscosity of the lubricating oil due to temperature rise is prevented, and the thickness of the minimum thickness oil film is maintained.</p> |
