Gas compresssor

Abstract

To abolish the O-ring for sealing the space on the rotor shaft rear end surface side. There are provided at the ends of a tubular cylinder a front side block and a rear side block, and a rotor rotatable by a rotor shaft is arranged in a cylinder, there being formed in the rotor vane grooves in which vanes are accommodated so as to be capable of advancing and retreating and vane back pressure chambers, there being further provided a high pressure chamber and an oil sump portion, a lubricant oil space being provided in the rear side block and on the rear end surface side of the rotor shaft, there being provided an oil supply passage for supplying oil to the lubricant oil space from the oil sump portion, there being provided in the rear side block or in the rotor shaft a vane back pressure chamber oil passage 40 whose one end communicates with the oil accommodating space and whose other end communicates with the vane back chambers. The space on the rotor shaft rear end surface side can be formed solely by the rear side block, and the O-ring for sealing the high pressure chamber is abolished to thereby achieve an improvement in reliability. Due to the abolishment of the O-ring, it is also possible to achieve a reduction in cost and assembly man-hour.

What is claimed is:  
     
         1 . A gas compressor comprising: 
 a cylinder;    a front side block and a rear side block situated at the axial ends of the cylinder;    a rotor rotatably arranged in the cylinder;    a vane groove provided in the rotor;    a vane back pressure chamber provided to an inner peripheral-side of the vane groove;    a vane accommodated in the vane groove so as to be capable of advancing and retreating;    a rotor shaft for rotating the rotor;    a high pressure chamber into which compressed gas is discharged from the cylinder;    an oil sump portion in which oil is stored and to which the pressure of the high pressure chamber is applied;    a lubricant oil space is arranged inside the rear side block and on the side of the rear end surface of the rotor shaft;    an oil supply passage for supplying oil from the oil sump portion to the lubricant oil space; and    an oil passage is formed in the rear side block or in the rotor shaft, one end of the oil passage communicating with the lubricant oil space and the other end communicating with the vane back pressure chamber.    
     
     
         2 . A gas compressor according to  claim 1 , wherein there is formed in the front end surface of the rear side block a flat groove communicating with the vane back pressure chamber, and that the flat groove is connected to the oil passage to establish communication between the oil passage and the vane back pressure chamber.  
     
     
         3 . A gas compressor according to  claim 1 , wherein the vane back pressure chamber is formed in the rotor shaft along the axial direction, and that the oil passage is radially deflected on the cylinder side to communicate with the vane back pressure chamber, there being arranged in the oil passage a throttle valve for limiting the opening area of the oil passage by a force sucking oil toward the vane back pressure chamber generated in the oil passage.