To provide a small displacement operation control mechanism and a control method which can prevent generation of chattering at the time of small displacement operation and increase a compression displacement variable range.
At a front side plate 3F, a bypass hole 11 is formed so that a compression chamber 6 and a suction chamber 9 may be communicated with each other, and a control valve mechanism 12 is formed in the direction orthogonal to the bypass hole 11 (compression capacity control mechanism). At a rear side plate 3R, on the other hand, an auxiliary pressure introduction hole 31 which communicates a pressure groove 29 continuous to a back pressure chamber with a separation chamber 17 is formed, and at the auxiliary pressure introduction hole 31, a ball valve 33 which is energized in such a direction as the auxiliary pressure introduction hole 31 is opened by the pressure of a spring 34 is anchored (back pressure control mechanism). When the difference pressure between the discharge pressure in the separation chamber 17 and the pressure in the back pressure chamber is under the spring pressure, the auxiliary pressure introduction hole 31 is opened and the discharge pressure in the separation chamber 17 is fed directly into the back pressure chamber, thus it is possible to eliminate a concern of insufficient back pressure.
WATANABE YASUSHI
NAKAYA TAKESHI
