Piston Type Compressor

Abstract

Each suction port 43 of a cylinder block 11 has a narrow passage 50 located at a top dead center side and a wide passage 51 located at a bottom dead center side. A suction communication passage 45 of a rotary valve 41 passes by a first succeeding end 50 b of the narrow passage 50 before passing by a second succeeding end 51 b of the wide passage 51 . A high-pressure groove 47 of a residual gas bypass groove 46 faces only a narrow passage 50 of a suction port 43 A that corresponds to a high-pressure side compression chamber 26 when in communication with the suction port 43 A. A width Tc between the first succeeding end 50 b and a second preceding end 51 a of the wide passage 51 in the rotation direction of the rotary valve 41 is smaller than a seal width W of a seal region S between the high-pressure groove 47 and the outlet 45 b of the suction communication passage 45 . This reduces the suction loss amount of gas in each compression chamber and improves the compression efficiency while advancing the timing at which the suction of gas into the compression chamber starts.

1 . A piston type compressor comprising a rotation shaft, a cylinder block having a plurality of cylinder bores arranged around the rotation shaft, a piston accommodated in each of the cylinder bores, and a rotary valve rotated in synchronization with the rotation shaft;
 wherein the piston defines a compression chamber in the cylinder bore, the cylinder block (has a plurality of suction ports each of which communicates a suction pressure region to the corresponding compression chamber, and the piston reciprocates between a bottom dead center that maximizes the volume of the compression chamber and a top dead center that minimizes the volume of the compression chamber so as to draw gas from the suction pressure region into the compression chamber through the rotary valve, compress the gas in the compression chamber, and discharge the gas from the compression chamber; and   the rotary valve has a suction communication passage and a residual gas bypass passage, the rotary valve is rotated so that the suction communication passage sequentially communicates each of the suction port with the suction pressure region and so that the residual gas bypass passage communicates the suction port corresponding to the compression chamber at the high-pressure side after discharging has been performed with the suction port corresponding to the compression chamber at the low-pressure side, and a portion of an outer circumferential surface of the rotary valve facing openings of the suction ports forms a seal region that prevents the residual gas bypass passage from being communicated with the suction communication passage through the openings of the suction ports, the piston type compressor being characterized in that:   each of the suction ports has a narrow passage located at a top dead center side and a wide passage located at a bottom dead center side, the narrow passage has an opening facing the outer circumferential surface of the rotary valve with a width in a rotation direction of the rotary valve that is smaller than a width of an opening of the wide passage;   the opening of the narrow passage has a first preceding end and a first succeeding end, wherein the suction communication passage of the rotating rotary valve first passes by the first preceding end and then passes by the first succeeding end, and the opening of the wide passage has a second preceding end and a second succeeding end, wherein the suction communication passage of the rotating rotary valve first passes by the second preceding end and then passes by the second succeeding end;   the suction communication passage passes by the first succeeding end before passing by the second succeeding end;   the residual gas bypass passage has a high-pressure opening, and the high-pressure opening faces only the narrow passage of the suction port that corresponds to the high-pressure side compression chamber when in communication with the suction port;   the narrow passage is arranged to enable communication with the compression chamber defined by the piston located at the top dead center; and   a width between the first succeeding end and the second preceding end in the rotation direction of the rotary valve is smaller than a dimension of a portion of the seal region between the high-pressure opening and an opening of the suction communication passage, and the opening of the suction communication passage comes into communication with the wide passage immediately after the narrow passage is closed by the seal region.   
   
   
       2 . The piston type compressor according to  claim 1 , wherein the wide passage is arranged continuously with the narrow passage. 
   
   
       3 . The piston type compressor according to  claim 1 , wherein the narrow passage is arranged closer to the second preceding end with respect to the wide passage. 
   
   
       4 . The piston type compressor according to  claim 3 , wherein the first preceding end and the second preceding end lie along the same straight line. 
   
   
       5 . A piston type compressor comprising a rotation shaft, a cylinder block having a plurality of cylinder bores arranged around the rotation shaft, a piston accommodated in each of the cylinder bores, and a rotary valve rotated in synchronization with the rotation shaft;
 wherein the piston defines a compression chamber in the cylinder bore, the cylinder block has a plurality of suction ports each of which communicates a suction pressure region to the corresponding compression chamber, and the piston reciprocates between a bottom dead center that maximizes the volume of the compression chamber and a top dead center that minimizes the volume of the compression chamber so as to draw gas from the suction pressure region into the compression chamber through the rotary valve, compress the gas in the compression chamber, and discharge the gas from the compression chamber; and   the rotary valve has a suction communication passage and a residual gas bypass passage, the rotary valve is rotated so that the suction communication passage sequentially communicates each of the suction port with the suction pressure region and so that the residual gas bypass passage communicates the suction port corresponding to the compression chamber at the high-pressure side after discharging has been performed with the suction port corresponding to the compression chamber at the low-pressure side, and a portion of an outer circumferential surface of the rotary valve facing openings of the suction ports forms a seal region that prevents the residual gas bypass passage from being communicated with the suction communication passage through the openings of the suction ports, the piston type compressor being characterized in that:   each of the suction ports has a wide passage located at a top dead center side and a narrow passage located at a bottom dead center side, the narrow passage has an opening facing the outer circumferential surface of the rotary valve with a width in a rotation direction of the rotary valve that is smaller than a width of an opening of the wide passage;   the opening of the narrow passage has a first preceding end and a first succeeding end, wherein the suction communication passage of the rotating rotary valve first passes by the first preceding end and then passes by the first succeeding end, and the opening of the wide passage has a second preceding end and a second succeeding end, wherein the suction communication passage of the rotating rotary valve first passes by the second preceding end and then passes by the second succeeding end;   the suction communication passage passes by the first succeeding end before passing by the second succeeding end;   the residual gas bypass passage has a high-pressure opening, and the high-pressure opening faces only the narrow passage of the suction port that corresponds to the high-pressure side compression chamber when in communication with the suction port;   the wide passage is arranged continuously with the narrow passage, and the wide passage is arranged to enable communication with the compression chamber defined by the piston located at the top dead center; and   a width between the first succeeding end and the second preceding end in the rotation direction of the rotary valve is smaller than a dimension of a portion of the seal region between the high-pressure opening and an opening of the suction communication passage, and the opening of the suction communication passage comes into communication with the wide passage immediately after the narrow passage is closed by the seal region.   
   
   
       6 . The piston type compressor according to  claim 5 , wherein the narrow passage is arranged closer to the second preceding end with respect to the wide passage. 
   
   
       7 . The piston type compressor according to  claim 6 , wherein the first preceding end and the second preceding end lie along the same straight line. 
   
   
       8 . The piston type compressor according to  claim 2 , wherein the narrow passage is arranged closer to the second preceding end with respect to the wide passage. 
   
   
       9 . The piston type compressor according to  claim 8 , wherein the first preceding end and the second preceding end lie along the same straight line.