Piston compressor

Abstract

A piston compressor includes first and second cylinder blocks having an inlet port and a swash plate chamber, a drive shaft having first and second guide holes, and a swash plate having first and second supply ports. The swash plate chamber communicates with the inlet port and also with the first and second guide holes via the first and second supply ports, respectively. A distance from the inlet port to the first supply port when the first supply port is moved closest to the inlet port is greater than a distance from the inlet port to the second supply port when the second supply port is moved closest to the inlet port, and the smallest flow passage area in the first supply port and the first guide hole is greater than the smallest flow passage area in the second supply port and the second guide hole.

1 . A piston compressor comprising:
 a first cylinder block having a first shaft hole, a plurality of first cylinder bores and a plurality of first admission ports, wherein the first cylinder bores are formed around the first shaft hole and communicate with the first shaft hole via the respective first admission ports;   a second cylinder block having a second shaft hole, a plurality of second cylinder bores and a plurality of second admission ports, wherein the second cylinder bores are formed around the second shaft hole and communicate with the second shaft hole via the respective second admission ports, wherein the first cylinder block and the second cylinder block are joined together, wherein the first cylinder block and the second cylinder block form a swash plate chamber between the first cylinder bores and the second cylinder bores, wherein one of the first cylinder block and the second cylinder block has therein an inlet port connected to the swash plate chamber for allowing refrigerant gas to be drawn thereinto;   a drive shaft rotatably supported at the first shaft hole and the second shaft hole by the first cylinder block and the second cylinder block, respectively, the drive shaft having therein an axial hole, a first suction guide hole, a second suction guide hole, a first guide hole and a second guide hole, wherein the axial hole extends in axial direction of the drive shaft, wherein the first suction guide hole communicates with the first guide hole via the axial hole and is communicable with the first admission ports of the first cylinder block, wherein the second suction guide hole communicates with the second guide hole via the axial hole and is communicable with the second admission ports of the second cylinder block;   a swash plate mounted on the drive shaft in the swash plate chamber for rotating therewith integrally, wherein the swash plate has a boss portion fitted on the drive shaft and a cam portion formed integrally with the boss portion, wherein the boss portion has therein a first supply port and a second supply port, wherein the first supply port communicates with the first guide hole of the drive shaft and the swash plate chamber, wherein the second supply port communicates with the second guide hole of the drive shaft and the swash plate chamber, wherein the first supply port and the second supply port are spaced from each other in rotation direction of the swash plate; and   a plurality of double-headed pistons received in the respective first and second cylinder bores and engaged with the cam portion, wherein the rotation of the cam portion with the drive shaft causes the double-headed pistons to reciprocate in the respective first and second cylinder bores, wherein opposite heads of the double-headed pistons and the first and second cylinder bores respectively define first compression chambers and second compression chambers, wherein the first compression chamber and the second compression chamber are communicable with the first admission port and the second admission port, respectively;   wherein the first supply port, the first guide hole, the axial hole, the first suction guide hole and the first admission ports cooperate to form a first suction flow passage for allowing the refrigerant gas in the swash plate chamber to be drawn into each first compression chamber on a suction stroke of the double-headed piston for the first compression chamber,   wherein the second supply port, the second guide hole, the axial hole, the second suction guide hole and the second admission ports cooperate to form a second suction flow passage for allowing the refrigerant gas in the swash plate chamber to be drawn into each second compression chamber on a suction stroke of the double-headed piston for the second compression chamber, and   wherein a distance from the inlet port to the first supply port when the first supply port is moved closest to the inlet port is greater than a distance from the inlet port to the second supply port when the second supply port is moved closest to the inlet port, wherein the smallest flow passage area in the first supply port and the first guide hole is greater than the smallest flow passage area in the second supply port and the second guide hole.   
   
   
       2 . The piston compressor according to  claim 1 , wherein the respective flow passage areas of the first supply port and the first guide hole are greater than the flow passage areas of the second supply port and the second guide hole. 
   
   
       3 . The piston compressor according to  claim 1 , wherein the flow passage area of the first guide hole is equal to the flow passage area of the second guide hole. 
   
   
       4 . The piston compressor according to  claim 1 , wherein the flow passage area of the first supply port is equal to the flow passage area of the second supply port. 
   
   
       5 . The piston compressor according to  claim 1 , wherein when the drive shaft rotates, the shortest flow path from the inlet port to the first suction guide hole through the first supply port is longer than the shortest flow path from the inlet port to the second suction guide hole through the second supply port, and wherein flow passage area of the first suction guide hole is greater than flow passage area of the second suction guide hole. 
   
   
       6 . The piston compressor according to  claim 1 , wherein when the drive shaft rotates, flow path from the inlet port to each first admission port through the first supply port is longer than flow path from the inlet port to the corresponding second admission port through the second supply port, and wherein flow passage area of the first admission port is greater than flow passage area of the second admission port. 
   
   
       7 . The piston compressor according to  claim 1 , wherein each of the first and second admission ports is in the form of a round hole as viewed in cross section. 
   
   
       8 . The piston compressor according to  claim 1 , wherein when the drive shaft rotates, flow path from the inlet port to each first admission port through the first supply port is longer than flow path from the inlet port to the corresponding second admission port through the second supply port, and wherein the first admission port is in the form of a round hole as viewed in cross section and the second admission port is in the form of an elongated hole as viewed in cross section. 
   
   
       9 . The piston compressor according to  claim 1 , wherein a projection is formed on the outer surface of the boss portion which is formed by a trailing side of the opening of the first supply port with respect to the rotation direction of the swash plate. 
   
   
       10 . The piston compressor according to  claim 1 , wherein the first supply port is inclined from radial direction of the boss portion so as to guide the refrigerant gas into the axial hole by the rotation of the swash plate.