| 摘要 |
PROBLEM TO BE SOLVED: To improve lubrication performance of a contact portion between a stem end and a tappet at a low oil temperature, and to improve lubrication performance between a valve stem and a cotter at a high oil temperature. ! SOLUTION: A valve structure of an engine includes a valve member 5, a cotter 8 disposed at a stem end side of the valve stem 5b, and a retainer 7 disposed on an outer periphery of the cotter 8, and further includes clearance adjustment means for closing an oil flow-down clearance formed between the valve stem 5b and the retainer 7 or an inlet at the other end side of the oil flow-down clearance when a temperature of an oil is low, and opening the oil flow-down clearance or the inlet at the other end side of the oil flow-down clearance when the temperature is high, by using the difference in thermal expansion coefficients. The clearance adjusting means includes the valve stem 5b, and the cotter 8 or an O-ring 9 disposed at a stem end side of the cotter 8, and makes a therma |
