Heat insulating structure in piston type compressor

Abstract

A heat insulating structure in a piston type compressor includes a heat insulating member. The piston type compressor includes a cylinder block and a cover housing connected to the cylinder block, a piston is accommodated in a cylinder bore defined in the cylinder block to define a compression chamber. A suction pressure region and a discharge pressure region are defined in the cover housing. The piston is reciprocated in the cylinder bore in accordance with rotation of a rotary shaft so that refrigerant gas is drawn from the suction pressure region to the compression chamber and discharged from the compression chamber to the discharge pressure region. The heat insulating member has a predetermined shape and is located in the cylinder block. The heat insulating member has an inner peripheral surface that defines the cylinder bore.

1 . A heat insulating structure in a piston type compressor including a cylinder block and a cover housing connected to the cylinder block, a piston being accommodated in a cylinder bore defined in the cylinder block to define a compression chamber, a suction pressure region and a discharge pressure region being defined in the cover housing, the piston being reciprocated in the cylinder bore in accordance with rotation of a rotary shaft so that refrigerant gas is drawn from the suction pressure region to the compression chamber and discharged from the compression chamber to the discharge pressure region, comprising: 
 a heat insulating member having a predetermined shape and located in the cylinder block, the heat insulating member having an inner peripheral surface that defines the cylinder bore.    
   
   
       2 . The heat insulating structure according to  claim 1 , wherein a hole is formed in the cylinder block for forming the compression chamber, the heat insulating member having a cylindrical shape and being inserted into the hole.  
   
   
       3 . The heat insulating structure according to  claim 2 , wherein a valve plate is interposed between the cylinder block and the cover housing to separate the compression chamber from the suction pressure region and the discharge pressure region, the heat insulating member including a flange at its end near the valve plate, the flange being sandwiched between the cylinder block and the valve plate.  
   
   
       4 . The heat insulating structure according to  claim 2 , wherein a valve forming plate of metal is interposed between the valve plate and the cylinder block, a seal ring being interposed between the valve forming plate and the cylinder block so as to surround an axial line of the rotary shaft and the heat insulating member.  
   
   
       5 . The heat insulating structure according to  claim 2 , wherein a valve plate is interposed between the cylinder block and the cover housing to separate the compression chamber from the suction pressure region and the discharge pressure region, a protrusion being formed on an inner peripheral surface of the cylinder block that defines the hole, the heat insulating member being sandwiched between the protrusion and the valve plate.  
   
   
       6 . The heat insulating structure according to  claim 2 , wherein the heat insulating member includes an end wall that faces a top end surface of the piston.  
   
   
       7 . The heat insulating structure according to  claim 1 , wherein the heat insulating member is an annular block included in the cylinder block, the annular block surrounds an axial line of the rotary shaft, the annular block having the cylinder bore.  
   
   
       8 . The heat insulating structure according to  claim 1 , wherein the heat insulating member is made of synthetic resin.  
   
   
       9 . The heat insulating structure according to  claim 1 , wherein the heat insulating member is made of one of hard rubber and ceramics.  
   
   
       10 . The heat insulating structure according to  claim 1 , wherein a top end surface of the piston is covered with another heat insulating member.  
   
   
       11 . The heat insulating structure according to  claim 1 , wherein the piston includes a head portion having a peripheral surface, the peripheral surface of the head portion is covered with a coating layer made of the same material as the heat insulating member.  
   
   
       12 . The heat insulating structure according to  claim 1 , wherein the refrigerant gas is carbon dioxide.