Suction structure in piston type compressor

Abstract

A suction structure is provided for allowing refrigerant from a suction pressure region in a piston type compressor. The compressor includes a rotary valve. The suction structure includes a shifting device which shifts between a connecting state and a disconnecting state. In the connecting state an outlet of a supply passage of the rotary valve is connected to a suction pressure region and in the disconnecting state the outlet of the supply passage is disconnected from the suction pressure region. The shifting device includes a valve body, a return spring, and a permanent magnet. The valve body is movable between a connecting position and a disconnecting position. The return spring urges the valve body from the connecting position toward the disconnecting position. The permanent magnet attracts the valve body by magnetic force from the connecting position toward the disconnecting position.

1 . A suction structure for allowing refrigerant from a suction pressure region in a piston type compressor, wherein cylinder bores for accommodating a respective piston are arranged around a rotary shaft, wherein a cam body is formed with the rotary shaft, wherein the piston is engaged with the cam body so that rotation of the rotary shaft is transmitted to the piston, wherein a compression chamber is defined by the piston in the respective cylinder bore, wherein a rotary valve is rotated integrally with the rotary shaft, wherein the rotary valve has a supply passage for introducing the refrigerant from the suction pressure region to the compression chamber, the suction structure comprising:
 a shifting device for shifting between a connecting state and a disconnecting state, wherein in the connecting state an outlet of the supply passage is connected to the suction pressure region and in the disconnecting state the outlet of the supply passage is disconnected from the suction pressure region, the shifting device including;
 a valve body movable between a connecting position and a disconnecting position, wherein the connecting position corresponds to the connecting state and the disconnecting position corresponds to the disconnecting state; 
 a return spring urging the valve body from the connecting position toward the disconnecting position; and 
 a permanent magnet for attracting the valve body by magnetic force from the connecting position toward the disconnecting position. 
   
   
   
       2 . The suction structure according to  claim 1 , wherein the compressor has a housing and the permanent magnet is fixed to the housing. 
   
   
       3 . The suction structure according to  claim 2 , wherein the valve body is in contact with the permanent magnet when the valve body is in the disconnecting position. 
   
   
       4 . The suction structure according to  claim 3 , wherein the valve body is in surface contact with the permanent magnet. 
   
   
       5 . The suction structure according to  claim 1 , wherein the valve body disconnects an inlet of the supply passage from the suction pressure region when the shifting device is in the disconnecting state. 
   
   
       6 . The suction structure according to  claim 1 , wherein the compressor includes a cylinder block in which the cylinder bores are formed, wherein a rear housing is connected to the cylinder block, wherein a suction chamber as the suction pressure region is formed in the rear housing, wherein the valve body is provided in the rear housing. 
   
   
       7 . The suction structure according to  claim 6 , the valve body is moved between the connecting position and the disconnecting position in the direction of a rotary axis of the rotary shaft, and wherein the permanent magnet is fixed to an inner wall surface of the rear housing which extends so as to intersect with the movement direction of the valve body. 
   
   
       8 . The suction structure according to  claim 1 , wherein the compressor has a housing, and the housing includes a communication chamber and a suction chamber, wherein a partition wall separates the communication chamber from the suction chamber, and wherein the permanent magnet is formed with the partition wall. 
   
   
       9 . The suction structure according to  claim 1 , wherein the valve body includes a piston, a rod, a disk and a cylindrical body, wherein the piston is attracted by the permanent magnet, wherein the rod is connected to the piston, the disk and the cylindrical body, wherein the disk and the cylindrical body disconnect the outlet of the supply passage from the suction pressure region when the shifting device is in the disconnecting state. 
   
   
       10 . The suction structure according to  claim 1 , wherein the compressor has a housing, and wherein a plate formed of magnetic material is fixed to the housing and the permanent magnet is formed with the valve body so as to be moved to and apart from the plate. 
   
   
       11 . The suction structure according to  claim 1 , wherein the rotary shaft is connected to an external drive source through a clutch. 
   
   
       12 . A suction structure for allowing refrigerant to flow from a suction pressure region in a piston type compressor, wherein cylinder bores for accommodating a respective piston are arranged around a rotary shaft, wherein a cam body is formed with the rotary shaft, wherein the piston is engaged with the cam body so that rotation of the rotary shaft is transmitted to the piston, wherein a compression chamber is defined by the piston in the respective cylinder bore, wherein a valve mechanism is disposed adjacent to the compression chamber, the suction structure comprising:
 a shifting device for shifting between a connecting state and a disconnecting state, wherein in the connecting state the compression chamber is connected to the suction pressure region upstream the shifting device through the valve mechanism and in the disconnecting state the compression chamber is disconnected from the suction pressure region upstream the shifting device through the valve mechanism, the shifting device including;
 a valve body movable between a connecting position and a disconnecting position, wherein the connecting position corresponds to the connecting state and the disconnecting position corresponds to the disconnecting state; 
 a return spring urging the valve body from the connecting position toward the disconnecting position; and 
 a permanent magnet for attracting the valve body by magnetic force from the connecting position toward the disconnecting position. 
   
   
   
       13 . A piston type compressor comprising:
 a housing;   cylinder bores formed in the housing, wherein the cylinder bores are arranged around a rotary shaft;   pistons accommodated in the respective cylinder bore;   a cam body formed with the rotary shaft, wherein the piston is engaged with the cam body so that rotation of the rotary shaft is transmitted to the piston;   a compression chamber defined by the piston in the respective cylinder bore;   a rotary valve rotated integrally with the rotary shaft, wherein the rotary valve includes a supply passage for introducing refrigerant from a suction pressure region in the compressor to the compression chamber; and   a shifting device for shifting between a connecting state and a disconnecting state, wherein in the connecting state an outlet of the supply passage is connected to the suction pressure region and in the disconnecting state the outlet of the supply passage is disconnected from the suction pressure region, the shifting device including;
 a valve body movable between a connecting position and a disconnecting position, wherein the connecting position corresponds to the connecting state and the disconnecting position corresponds to the disconnecting state; 
 a return spring urging the valve body from the connecting position toward the disconnecting position; and 
 a permanent magnet for attracting the valve body by magnetic force from the connecting position toward the disconnecting position.