| 摘要 |
PROBLEM TO BE SOLVED: To reduce a compression load by gradually increasing a pressure of a crank chamber to decrease a delivery capacity, in a condition of rotation at a high speed and operation of large delivery capacity. SOLUTION: In the intermediate section of an extraction passage 29 connecting a crank chamber 15 and a suction pressure region 13a, an opening/ closing valve 33 is arranged. In a spring 37 of this opening/closing valve 33, a valve unit 36 is energized in an opening direction of the extraction passage 29. When a rotational speed of a drive shaft 16 is increased to a prescribed value or more, by centrifugal force acting in a counterweight 38, the valve unit 36 is moved to a position closing a valve hole 34. In this way, the extraction passage 29 is shutoff, and extraction is stopped of refrigerant gas to the suction pressure region 13a from the crank chamber 15 through the extraction passage 29. By blow-by-gas flowing in through a clearance between a piston 21 and a cylinder bore 12a, a pressure in the crank chamber 15 is slowly increased. |
