| 摘要 |
PROBLEM TO BE SOLVED: To minimize increment of clearance between a crankshaft and a bearing metal in the bearing structure of the crankshaft, reduce generation of vibration noise by preventing backlash or the like of the crankshaft, improve durability of the bearing metal by reducing abrasion of the bearing metal, suppress increase of weight by minimizing usage of iron components, facilitate accuracy control of a positioning pin of a die, and eliminate a manufacturing problem to facilitate mass production. SOLUTION: A lower case bearing part comprises a bearing peripheral part having a casted iron member around the bearing metal and a bearing lower part made of light alloy provided integrally with the lower part of the bearing peripheral part. The bearing peripheral part has an engaging part engaging with the positioning pin of the die during the casting with the die of a crank lower case, and also a projection reaching the lower end of the bearing lower part.
|
