Compressor

Abstract

The present invention is to reduce a pressure drop in a compressor caused by a suction throttle valve. A compressor 100 includes: a suction chamber 141 ; a suction passage 104 c communicating with the suction chamber 141 ; and a suction throttle valve 200 for changing the opening degree of the suction passage 104 c . Here, pressure in a region of the suction chamber 141 , apart from another region of the suction chamber 141 in the neighborhood of the suction throttle valve 200 and lower in pressure, is introduced into the suction throttle valve 200 through a pressure introducing passage 104 g . This increases the pressure difference before and behind the suction throttle valve 200 to make the opening degree larger. As a result, a pressure drop by the suction throttle valve 200 can be reduced to suppress performance degradation due to providing the suction throttle valve 200.

1 . A compressor comprising: a suction chamber annularly formed around axis of a drive shaft; a suction passage communicating with the suction chamber; and a suction throttle valve for changing an opening degree of the suction passage according to a pressure difference between pressure in the suction chamber and pressure in the suction passage,
 wherein pressure in a region of the suction chamber, apart from another region of the suction chamber in the neighborhood of the suction throttle valve and lower in pressure, is introduced into the suction throttle valve through a pressure introducing passage.   
     
     
         2 . The compressor according to  claim 1 , further comprising a discharge chamber surrounded by the suction chamber,
 wherein the pressure introducing passage is provided to extend across the discharge chamber in projection in an axial direction of the drive shaft.   
     
     
         3 . The compressor according to  claim 1 , wherein the pressure introducing passage guides, to the suction throttle valve, pressure in a region of the suction chamber that faces the region of the suction chamber in the neighborhood of the suction throttle valve across axis of the drive shaft. 
     
     
         4 . The compressor according to  claim 1 , wherein
 the suction chamber has a narrowed portion in which a cross-section area of a flow passage is partially narrowed, and   the pressure introducing passage guides, to the suction throttle valve, pressure in a region on a farther side from the region of the suction chamber in the neighborhood of the suction throttle valve between regions across the narrowed portion of the suction chamber.   
     
     
         5 . The compressor according to  claim 4 , further comprising
 a discharge chamber surrounded by the suction chamber,   wherein a discharge passage communicating with the discharge chamber is provided across the suction chamber along a radial direction of the drive shaft, and the narrowed portion is formed by the discharge passage.   
     
     
         6 . The compressor according to  claim 1 , wherein
 the suction passage is provided in a region outside of the annular suction chamber to extend in the radial direction of the drive shaft,   the suction throttle valve includes a valve element and a valve housing for housing the valve element displaceably in the radial direction of the drive shaft, and   the pressure introducing passage communicates with an inner end of the valve housing in the radial direction of the drive shaft.   
     
     
         7 . The compressor according to  claim 6 , wherein
 in the valve housing, an inlet hole communicating with the suction passage is formed at an outer end in the radial direction of the drive shaft, an outlet hole communicating with the suction chamber is formed in an intermediate peripheral wall, and a communication hole communicating with the pressure introducing passage is formed at the inner end in the radial direction of the drive shaft, and   the valve element is displaced in the radial direction of the drive shaft to change an opening area of the outlet hole according to a pressure difference between pressure in the suction chamber introduced into the valve housing through the communication hole and pressure in the suction passage introduced into the valve housing through the inlet hole.   
     
     
         8 . The compressor according to  claim 2 , wherein the pressure introducing passage guides, to the suction throttle valve, pressure in a region of the suction chamber that faces the region of the suction chamber in the neighborhood of the suction throttle valve across axis of the drive shaft. 
     
     
         9 . The compressor according to  claim 2 , wherein
 the suction chamber has a narrowed portion in which a cross-section area of a flow passage is partially narrowed, and   the pressure introducing passage guides, to the suction throttle valve, pressure in a region on a farther side from the region of the suction chamber in the neighborhood of the suction throttle valve between regions across the narrowed portion of the suction chamber.   
     
     
         10 . The compressor according to  claim 9 , further comprising
 a discharge chamber surrounded by the suction chamber,   wherein a discharge passage communicating with the discharge chamber is provided across the suction chamber along a radial direction of the drive shaft, and the narrowed portion is formed by the discharge passage.   
     
     
         11 . The compressor according to  claim 2 , wherein
 the suction passage is provided in a region outside of the annular suction chamber to extend in the radial direction of the drive shaft,   the suction throttle valve includes a valve element and a valve housing for housing the valve element displaceably in the radial direction of the drive shaft, and   the pressure introducing passage communicates with an inner end of the valve housing in the radial direction of the drive shaft.   
     
     
         12 . The compressor according to  claim 5 , wherein
 the suction passage is provided in a region outside of the annular suction chamber to extend in the radial direction of the drive shaft,   the suction throttle valve includes a valve element and a valve housing for housing the valve element displaceably in the radial direction of the drive shaft, and   the pressure introducing passage communicates with an inner end of the valve housing in the radial direction of the drive shaft.