Piston type compressor

Abstract

In a piston type compressor, a housing includes a cylinder block that forms plural cylinder bores and an accommodating hole at a center thereof. The valve port assembly connected to the cylinder block includes suction and discharge ports, suction and discharge valves made of flapper valves. An end portion of the drive shaft rotatably supported by the housing is slidably accommodated in the accommodating hole. The piston in each cylinder bore and the valve port assembly form a compression chamber. The cylinder block forms therein communication holes that connect each compression chamber to the end portion that forms therein a residual gas bypass passage. The residual gas bypass passage connects one communication hole, which communicates with the high-pressure side compression chamber that has finished discharge process of gas, to another communication hole, which communicates with the compression chamber that is lower in pressure than the high-pressure side compression chamber.

1 . A piston type compressor comprising: 
 a housing includes a cylinder block that forms a plurality of cylinder bores and an accommodating hole at a center thereof;    a valve port assembly connected to the cylinder block, the valve port assembly including suction ports, suction valves made of flapper valves, discharge ports, and discharge valves made of flapper valves;    a drive shaft rotatably supported by the housing and surrounded by the cylinder bores, an end portion of the drive shaft being slidably accommodated in the accommodating hole; and    a piston accommodated in each of the cylinder bores, the piston and the valve port assembly forming a compression chamber, wherein the cylinder block forms therein communication holes that connect each of the compression chambers to the end portion of the drive shaft, the end portion of the drive shaft forming therein a residual gas bypass passage, wherein the residual gas bypass passage connects one communication hole, which communicates with the compression chamber on a high-pressure side that has finished discharge process of gas, to another communication hole, which communicates with the compression chamber that is lower in pressure than the high-pressure side compression chamber, and wherein as the piston reciprocates, gas being introduced into the compression chamber through the suction port by pushing away the suction valve, compressed in the compression chamber and discharged from the compression chamber through the discharge port by pushing away the discharge valve.    
   
   
       2 . The piston type compressor according to  claim 1 , wherein the residual gas bypass passage at least partially includes a groove that is formed in an outer peripheral surface of the end portion of the drive shaft sliding on an inner peripheral surface of the accommodating hole.  
   
   
       3 . The piston type compressor according to  claim 2 , wherein the residual gas bypass passage is wholly formed by the groove.  
   
   
       4 . The piston type compressor according to  claim 1 , wherein the residual gas bypass passage at least partially includes a groove that extends in a direction along an axis of the drive shaft.  
   
   
       5 . The piston type compressor according to  claim 1 , wherein the residual gas bypass passage at least partially includes a hole that radially extends through the drive shaft.  
   
   
       6 . The piston type compressor according to  claim 5 , wherein the residual gas bypass passage is wholly formed by the hole.  
   
   
       7 . The piston type compressor according to  claim 1 , wherein the residual gas bypass passage includes: 
 a groove formed in an outer peripheral surface of the end portion of the drive shaft sliding on an inner peripheral surface of the accommodating hole; and    a hole radially extending through the drive shaft.    
   
   
       8 . The piston type compressor according to  claim 1 , wherein the compressor includes the even-numbered cylinder bores.  
   
   
       9 . The piston type compressor according to  claim 8 , wherein the compressor includes six cylinder bores.  
   
   
       10 . The piston type compressor according to  claim 1 , wherein the compressor is a variable displacement type.  
   
   
       11 . The piston type compressor according to  claim 1 , wherein the piston is a single-headed type.