| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a piston cooling device of an engine capable of reducing the capacity of an oil pump, and reducing the rotational friction of the engine.SOLUTION: A valve insertion hole 19 opening to the inside of a crank case 5 and intersecting an oil gallery 17 is formed on an upstream side to a connecting portion of the oil gallery 17 to which a piston cooling jet 18 is connected. In the valve insertion hole 19, a spring 20 is inserted, and a valve body 21 is inserted in a crank shaft 9 side rather than the spring 20. The valve body 21 is formed with an opening hole 22 for opening the oil gallery 17. A cam 23 rotating with the crank shaft 9 is formed with a cam surface 23a moving the valve body 21 to a position where the opening hole 22 opens the oil gallery 17 when a piston 8 moves from a lower dead point toward an upper dead point, and moving the valve body 21 to a position deviated from the position where the opening hole 22 opens the oil gallery 17 when the piston 8 moves from the upper dead point toward the lower dead point.</p> |
