Swash-plate type compressor

A swash-plate type compressor comprising:

• a rotary shaft;
• a swash-plate secured to said rotary shaft;
• a cylinder block rotatably supporting said rotary shaft, and consisting of two halves each having a plurality of circumferentially spaced cylinder bores which extend axially of said rotary shaft and have the centers on a circle whose center is located on the axis of said rotary shaft, said two halves being assembled in abutment with each other such that said cylinder bores in said respective two halves are in alignment with each other, said cylinder block having a swash-plate chamber rotatably accommodating said swash-plate and constituting a passage for sucked refrigerant gas;
• and
• a plurality of pistons slidably received in said cylinder bores and each having an engaging recess engaging said swash-plate,
• said cylinder block further having
• an inlet passage through which a stream of refrigerant gas is sucked therein,
• a continuously annular passage communicated with said inlet passage, concentric with said circle and open to said swash-plate chamber, said annular passage being formed circumferentially in a radially inward portion of the cylindrical wall of said cylinder block, having a diameter larger than that of a common circumcircle of said cylinder bores, and functioning as a by-pass for said sucked refrigerant gas flowing through said swash-plate chamber, and
• a plurality of circumferentially spaced, axially extending, holes communicated with said swash-plate chamber, said annular passage and said cylinder bores, and accommodating fixing bolts for clamping said two halves, said holes having a diameter larger than that of said fixing bolts so that an annular space formed between the inner surface of said holes and the outer surface of said bolts serves as a communicating passage to said cylinder bores, said diameter of said holes increasing with an angular distance of said holes as measured from a junction of said inlet passage and said annular passage, whereby the sucked refrigerant gas is evenly delivered to said plurality of pistons and a portion of each of said pistons adjacent to said engaging recess is cooled evenly on both radially inward and outward sides thereof.