Piston type compressor

Abstract

A piston type compressor comprises a housing, a rotary shaft supported by the housing, a cam mounted on the rotary shaft. The housing includes a discharge-pressure region and a suction-pressure region. The compressor further comprises an oil separator provided in the discharge-pressure region and an oil reservoir for storing lubricating oil from the oil separator. The rotary shaft has a regulating means for regulating the axial movement of the rotary shaft and for forming a clearance between the regulating means and the valve plate assembly. The clearance is communicated with the oil reservoir through a communication hole formed in the valve plate assembly so that the clearance functions as a throttle in an oil return passage extending from the oil separator to the inside of the compressor. A supply passage is formed in the rotary valve and in communication with the cam chamber in which a suction port is provided.

1 . A piston type compressor comprising: 
 a housing having a plurality of cylinder bores and a cam chamber, the housing being provided with a discharge-pressure region and a suction-pressure region therein;    a rotary shaft rotatably supported by the housing, the cylinder bores being arranged around the rotary shaft;    a cam accommodated in the cam chamber and rotatable integrally with the rotary shaft;    a valve plate assembly provided between the cylinder bores and the discharge-pressure region, the valve plate assembly having a communication hole thereon;    a piston accommodated in each of the cylinder bores and operatively connected to the rotary shaft, the piston and the valve plate assembly defining compression chamber in the respective cylinder bore;    an oil separator provided in the discharge-pressure region for separating lubricating oil contained in refrigerant discharged from the compression chambers;    an oil reservoir formed in the discharge-pressure region to store the lubricating oil separated by the oil separator, the oil reservoir being connected to the communication hole; and    a regulating means provided on the rotary shaft at an end position close to the valve plate assembly, the regulating means and the valve plate assembly forming a clearance in-between, wherein the regulating means is aligned with the communication hole so that the clearance is connected to the oil reservoir through the communication hole.    
   
   
       2 . The piston type compressor according to  claim 1  further comprising: 
 a rotary valve formed integrally with the rotary shaft and located adjacent to the valve plate assembly, the rotary valve having a supply passage and an introducing port, the supply passage extending axially inside the rotary valve and being in communication with the introducing port, the introducing port being capable of communicating with the cylinder bore in which the piston is in suction stroke, the supply passage being open at the end surface of the rotary valve, wherein the regulating means includes a closure cap closing the open end of the supply passage on the rotary valve.    
   
   
       3 . The piston type compressor according to  claim 2 , wherein the cam chamber is provided with a suction port connected to an evaporator in an external refrigerant circuit, the cam chamber being connected to the supply passage of the rotary valve.  
   
   
       4 . The piston type compressor according to  claim 2 , wherein the closure cap is press-fitted in the supply passage.  
   
   
       5 . The piston type compressor according to  claim 4 , wherein the closure cap includes: 
 a cap portion press-fitted in the supply passage; and    a flange portion which extends radially from a circumferential end of the cap portion, wherein the clearance is formed between the flange portion and the valve plate assembly.    
   
   
       6 . The piston type compressor according to  claim 4 , wherein the closure cap includes a cylindrical and hollow cap portion press-fitted in the supply passage.  
   
   
       7 . The piston type compressor according to  claim 1 , further comprising: 
 a thrust bearing provided for receiving axial load of the rotary shaft, wherein the regulating means has a surface for receiving pressure from the oil reservoir to urge the rotary shaft and the cam to the thrust bearing.    
   
   
       8 . The piston type compressor according to  claim 1 , wherein the oil separator is a centrifugal separator.  
   
   
       9 . The piston type compressor according to  claim 1 , wherein the compressor is of a fixed displacement type.  
   
   
       10 . The piston type compressor according to  claim 1 , wherein the clearance is a throttle for a passage between the discharge-pressure region and the suction-pressure region.