| 摘要 |
[PROBLEMS] Local stress concentration caused by rotational moment transmitted from a crankshaft is eased. [MEANS FOR SOLVING PROBLEMS] A crankshaft (6) and an installation hole (5) have two connection sections (12, 12, 22, 22) for connecting two main circular arc sections (11, 21) on the same circle and adjacent main circular arc sections (11, 11, 21, 21), and the opposite connection sections (12, 12, 22, 22) have a substantially parallel cross-sectional shape. The connection sections (22) of the installation hole (5) have a large circular arc shape projecting inward. Rotational force of the crankshaft (6) is transmitted to the installation hole (5), with the connection sections (12) of the crankshaft (6) and the large circular arc-shaped connection sections (22) of the installation hole (5) in linear contact with each other, so that a local stress value occurring at the installation hole (5) can be reduced. |
