| 摘要 |
PURPOSE: To improve the attaching strength of a crank shaft bearing and to reduce its weight by burying a cylindrical reinforcing member in the connecting bolt hole part of the crank shaft bearing for connecting this to a cylinder block and specifying its burying length in the crank shaft bearing. CONSTITUTION: A hole part 6 with a step is provided in a crank shaft bearing 5, a cylindrical reinforcing member 7 is forcibly inserted or cast in a large diameter part 6a having its inner diameter larger than that of a connecting bolt and the reinforcing member 7 is made of a metal having rigidity higher than that the crank shaft bearing 5. The connecting bolt is passed through the inside of the reinforcing member 7 and crank shaft bearing 5 is attached to a cylinder block 1. A length L for burying the reinforcing member 7 in the crank shaft bearing 5 is set by an expression. K represents a correction factor (0.5<=K<=1.5), R the journal diameter of the crank shaft 4 andθan angle between an engine explosion load direction and the overlapped surface 5a between the crank shaft bearing 5 and the cylinder viewing in the crank shaft direction block 1. Thus, the length of the reinforcing member 5 is made as short as possible so as to reduce the weigh of the crank shaft bearing and its attaching strength is increased to the maximum.
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