Piston compressor

Abstract

A piston compressor includes single-headed pistons individually received for reciprocal linear motion in cylinder bores, and is arranged to suppress the wear of these pistons with simple machining for wear prevention. The single-headed piston includes a first piston portion disposed in close contact with the cylinder bore, for sucking refrigerant thereinto and compressing the refrigerant, and a second piston portion adjacently formed in a crankcase-side end of the first piston portion and having a diameter smaller than that of the first piston portion, so as to be prevented from being in contact with the cylinder bore, or so as to apply, even if in contact therewith, a small thrust force to the cylinder bore.

What is claim d is:  
     
         1 . A piston compressor comprising: 
 cylinder bores formed in a cylinder block portion so as to be separated from one another;    single-headed pistons individually received for reciprocal motion in said cylinder bores; and    a motion conversion mechanism disposed in a crankcase for converting a rotary motion of a driving source into reciprocal motions of said single-headed pistons,    wherein each of said single-headed piston includes a first piston portion disposed in close contact with the corresponding cylinder bore for sucking and compressing refrigerant, and a second piston portion formed adjacent to an axial end portion of said first piston portion on a side of the crankcase and having a diameter smaller than that of said first piston portion.    
     
     
         2 . The piston compressor according to  claim 1 , wherein said second piston is formed with an annular oil groove for oil intake in vicinity of said first piston portion.  
     
     
         3 . The piston compressor according to  claim 1 , wherein said first piston portion has a distal end periphery that is formed into an R shape.  
     
     
         4 . The piston compressor according to  claim 2 , wherein said first piston portion has a distal end whose periphery is formed into an R shape.  
     
     
         5 . The piston compressor according to  claim 1 , wherein said first piston portion is coated at its outer peripheral face with a wear resistant material.  
     
     
         6 . The piston compressor according to  claim 2 , wherein said first piston portion is coated at its outer peripheral face with a wear resistant material.  
     
     
         7 . The piston compressor according to  claim 3 , wherein said first piston portion is coated at its outer peripheral face with a wear resistant material.  
     
     
         8 . The piston compressor according to  claim 4 , wherein said first piston portion is coated at its outer peripheral face with a wear resistant material.  
     
     
         9 . The piston compressor according to any one of claims  5 - 8 , wherein said wear resistant material mainly includes polytetrafluoroethylene.  
     
     
         10 . The piston compressor according to any one of claims  5 - 8 , wherein the refrigerant compressed in each of said cylinder bore is carbon dioxide refrigerant or hydro carbon refrigerant.