Piston type compressor

Abstract

In a piston type compressor, a piston is respectively accommodated in a plurality of cylinder bores arranged around a rotary shaft. A rotary valve has a suction guiding passage for introducing gas from a suction pressure region into a compression chamber when in communication therebetween. A suction timing control passage is formed in the rotary valve and is constantly in communication with the suction pressure region at first end, the suction timing control passage precedes the suction guiding passage communicating with the compression chamber at second end. A suction timing control valve is arranged in the control passage, having a valve body which opens and closes the control passage in response to difference between force resulting from pressure on a side of the suction pressure region to open the valve body and force resulting from pressure on a side of the compression chamber to close the valve body.

1 . A piston type compressor comprising: 
 a housing forming a suction pressure region and a plurality of cylinder bores which respectively forms a compression chamber;    a rotary shaft rotatably supported by the housing, the cylinder bores being arranged around the rotary shaft;    a piston accommodated in each cylinder bore;    a rotary valve having a suction guiding passage for introducing gas from the suction pressure region into the compression chamber, the gas being introduced from the suction pressure region into the compression chamber through the suction guiding passage when the compression chamber communicates with the suction guiding passage;    a suction timing control passage formed in the rotary valve, a first end of the suction timing control passage being constantly in communication with the suction pressure region, while a second end of the suction timing control passage precedes the suction guiding passage communicating with the compression chamber; and    a suction timing control valve arranged in the suction timing control passage, the suction timing control valve having a valve body which opens and closes the suction timing control passage in response to difference between force resulting from pressure on a side of the suction pressure region to open the valve body and force resulting from pressure on a side of the compression chamber to close the valve body.    
   
   
       2 . The piston type compressor according to  claim 1 , wherein the time when the second end of the suction timing control passage initiates communication with the compression chamber is during a volume-reducing process of the compression chamber or the time when the volume-reducing process completes.  
   
   
       3 . The piston type compressor according to  claim 1 , wherein the suction timing control valve is constituted of a poppet valve as the valve body.  
   
   
       4 . The piston type compressor according to  claim 3 , wherein the poppet as the valve body is operable to open and close the suction timing control passage by sliding along a rotation center axis of the rotary valve.  
   
   
       5 . The piston type compressor according to  claim 4 , wherein the poppet is arranged such that an axis of the poppet coincides the axis of the rotary valve.  
   
   
       6 . The piston type compressor according to  claim 5 , wherein the poppet is located in the rotary valve so as to be slidable on a cylindrical inner surface of an outer peripheral wall of the rotary valve.  
   
   
       7 . The piston type compressor according to  claim 1 , wherein the suction timing control valve is constituted of a reed valve.  
   
   
       8 . The piston type compressor according to  claim 1 , wherein the valve body of the suction timing control valve includes a first valve portion for opening and closing the suction timing control passage and a second valve portion for adjusting opening degree of the suction guiding passage, the second valve portion increasing opening degree of the suction guiding passage in a state where the first valve portion opens the suction timing control passage, while reducing opening degree of the suction guiding passage in a state where the first valve portion closes the suction timing control passage.  
   
   
       9 . The piston type compressor according to  claim 1 , wherein an introducing passage extends from the compression chamber for communication between the suction guiding passage and the compression chamber, the introducing passage being opened to face an outer peripheral surface of the rotary valve, a valve body of the suction timing control valve being located offset from an axis of the rotary valve.  
   
   
       10 . The piston type compressor according to  claim 9 , wherein the suction timing control valve is constituted of a poppet valve, a poppet of the poppet valve being located offset to a side of an axis of the piston relative to a hypothetical plane which includes the axis of the rotary valve and intersects vertically another hypothetical plane including the axis of the rotary valve and the axis of the piston positioned at a top dead center.  
   
   
       11 . The piston type compressor according to  claim 9 , wherein there is a state where the second end of the suction timing control passage and the suction guiding passage are simultaneously in communication with the same compression chamber.  
   
   
       12 . The piston type compressor according to  claim 9 , further comprising: 
 a cam plate operatively connected to the rotary shaft for converting rotation of the rotary shaft to reciprocation of the piston, displacement of the compressor being changed by varying stroke of the piston by varying inclination angle of the cam plate.    
   
   
       13 . A piston type compressor forming a first suction valve in a rotor integrally rotating with a rotary shaft, the first suction valve integrally rotating with rotation of the rotary shaft for opening and closing a gas passage between a suction pressure region and a compression chamber, comprising: 
 a second suction valve provided in the rotor, the second suction valve having a second port which precedes a first port of the first suction valve communicating with the compression chamber, the second suction valve opening and closing communication between the second port and the suction pressure region in response to difference between force resulting from pressure on a side of the suction pressure region to open the second suction valve and force resulting from pressure on a side of the compression chamber to close the second suction valve.