Reciprocating Compressor for Refrigerator

Abstract

The present invention provides a reciprocating compressor for a refrigerator capable of restraining an increase in temperature of a refrigerant discharged and increasing refrigerant compression efficiency. The compressor according to the present invention includes a housing ( 16 ) having cylinder bores ( 30 ), pistons ( 32 ) fitted in the respective cylinder bores ( 30 ) and each capable of reciprocating motion in the bore ( 30 ), an intermediate pressure chamber ( 68 ) arranged in the housing ( 16 ) and supplied with the refrigerant at a low temperature from a gas-liquid separator ( 10 ) of the refrigerator, and a rotary valve ( 78 ) arranged between the chambers ( 33, 68 ). The rotary valve ( 78 ) is rotated in association with a main shaft ( 34 ) of the compressor and opened to inject the low-temperature refrigerant into each compression chamber ( 33 ) from the intermediate pressure chamber ( 68 ) while the compression chamber ( 33 ) is in a process of compressing the refrigerant.

1 . A reciprocating compressor for a refrigerator, comprising:
 a housing having cylinder bores   pistons fitted in the respective cylinder bores to define compression chambers in the respective cylinder bores, said pistons each being capable of reciprocating motion in their own cylinder bore and each repeating, by their reciprocating motion, a process of sucking a refrigerant into their own compression chamber, compressing the sucked refrigerant in the compression chamber and discharging the compressed refrigerant from the compression chamber so that the discharged refrigerant is supplied to a refrigerant circulation path of the refrigerator, and   an introduction device arranged in said housing to allow an intermediate refrigerant to be introduced from the refrigerant circulation path into each compression chamber only for a predetermined period of time while the compression chamber is in the process of compressing the refrigerant, where the pressure of the intermediate refrigerant is above the pressure of the refrigerant being compressed in the compression chamber.   
   
   
       2 . The reciprocating compressor for the refrigerator according to  claim 1 , wherein the intermediate refrigerant allowed to be introduced into each compression chamber by said introduction device has a temperature lower than the temperature of the refrigerant being compressed in the compression chamber. 
   
   
       3 . The reciprocating compressor for the refrigerator according to  claim 1 , wherein
 said introduction device includes   an intermediate pressure chamber defined in said housing and supplied with the intermediate refrigerant from the refrigerant circulation path,   connection passages connecting the intermediate pressure chamber and the respective compression chambers, and   a valve associated with the connection passages to open and close the connection passages, where the valve opens each connection passage while the corresponding compression chamber is in the process of compressing the refrigerant and closes the connection passage before the refrigerant being compressed reaches to the pressure of the intermediate refrigerant in the intermediate pressure chamber.   
   
   
       4 . The reciprocating compressor for the refrigerator according to  claim 3 , wherein the valve is a rotary valve mechanically connected to a main shaft of the compressor to rotate integrally with the main shaft. 
   
   
       5 . The reciprocating compressor for the refrigerator according to  claim 3 , wherein the valve is a rotary valve caused to rotate by a motor independent from a main shaft of the compressor. 
   
   
       6 . The reciprocating compressor for the refrigerator according to  claim 3 , wherein the valve is a solenoid-operated valve. 
   
   
       7 . The reciprocating compressor for the refrigerator according to  claim 1 , further comprising a variable displacement mechanism capable of varying the amount of the compressed refrigerant discharged, where said variable displacement mechanism includes a swashplate. 
   
   
       8 . The reciprocating compressor for the refrigerator according to  claim 1 , wherein the refrigerant is carbon dioxide. 
   
   
       9 . The reciprocating compressor for the refrigerator according to  claim 1 , wherein the refrigerant includes a compound having hydrocarbons containing one or more double bond between carbon atoms.