Double-headed piston type compressor

A double-headed piston type compressor comprising:

• a front housing member;
• a rear housing member;
• a cylinder block located between the front housing member and the rear housing member, the cylinder block including a plurality of cylinder bores, and the front housing member, the rear housing member, and the cylinder block define a swash plate chamber;
• a suction pressure zone;
• double-headed pistons each of which is slidably inserted in one of the cylinder bores, wherein each double-headed piston defines a compression chamber close to the front housing member and a compression chamber close to the rear housing member, and one set of the compression chambers serves as first compression chambers and the other set of the compression chambers serves as second compression chambers;
• a rotary shaft rotatably supported in the cylinder block;
• a swash plate, which rotates with the rotary shaft in the swash plate chamber, the swash plate causes the double-headed pistons to reciprocate in the cylinder bores, and as a result, refrigerant is drawn into the compression chambers from the suction pressure zone and is compressed in and discharged from the compression chambers;
• a mechanism for drawing in the refrigerant to the first compression chambers, the mechanism being configured by a rotary valve, which includes an introduction passage for introducing the refrigerant from the suction pressure zone to the first compression chambers, but the mechanism being not configured by suction valves, which selectively open and close in accordance with the difference between the pressure in the suction pressure zone and the pressure in the first compression chambers;
• and
• a mechanism for drawing in the refrigerant to the second compression chambers, the mechanism being configured by suction valves, which selectively open and close in accordance with the difference between the pressure in the suction pressure zone and the pressure in the second compression chambers, but the mechanism being not configured by a rotary valve, which includes an introduction passage for introducing the refrigerant from the suction pressure zone to the second compression chambers, and
• wherein a phase difference occurs between the time at which refrigerant is discharged from each of the first compression chambers and the time at which refrigerant is discharged from each of the second compression chambers.