Scroll compressor

Abstract

In a scroll compressor according to the present invention, at least one injection port penetrating a second end plate of a fixed scroll at a position where the injection port is open to a first compression chamber or a second compression chamber in a compression stroke after the suction refrigerant is introduced and closed. Further, the discharge bypass port is disposed such that a volume ratio, which is a ratio of a suction volume to a discharge volume of the second compression chamber at which the refrigerant in the first compression chamber can be discharged, is smaller in the first compression chamber, which is one compression chamber having the large amount of the refrigerant injected from the injection port, than in the second compression chamber, which is the other compression chamber among the first compression chamber and the second compression chamber.

1 . A scroll compressor comprising:
 a fixed scroll including a first spiral wrap standing up from a first end plate of the fixed scroll; and   an orbiting scroll including a second spiral wrap standing up from a second end plate of the orbiting scroll,   wherein the first spiral wrap of the fixed scroll is engaged with the second spiral wrap of the orbiting scroll to define a compression chamber between the fixed scroll and the orbiting scroll,   the compression chamber includes:   a first compression chamber on an outer wall side of the second spiral wrap of the orbiting scroll; and   a second compression chamber on an inner wall side of the second spiral wrap of the orbiting scroll,   a suction volume of the first compression chamber is equal to a suction volume of the second compression chamber,   wherein the first end plate of the fixed scroll includes a central portion having a discharge port through which a refrigerant compressed in the compression chamber is discharged,   the scroll compressor further comprises:   a discharge bypass port through which the refrigerant compressed in the compression chamber is discharged before the compression chamber communicates with the discharge port is provided;   at least one injection port through which an intermediate-pressure refrigerant is injected into the first compression chamber and the second compression chamber, the at least one injection port penetrating the first end plate of the fixed scroll at a position where the injection port is open to the first compression chamber or the second compression chamber in a compression stroke after a suction refrigerant is introduced and closed, and   the discharge bypass port is disposed such that a volume ratio is made smaller in one of the first compression chamber and the second compression chamber having a large amount of the refrigerant injected from the injection port among the first compression chamber and the second compression chamber than in the other one of the first compression chamber and the second compression chamber, the volume ratio being a ratio of the suction volume to the discharge volume of the compression chamber at which the refrigerant in the compression chamber is able to be discharged.   
     
     
         2 . The scroll compressor of  claim 1 , wherein a check valve that allows flow of the refrigerant to the compression chamber and suppresses flow of the refrigerant from the compression chamber is provided in the injection port. 
     
     
         3 . The scroll compressor of  claim 1 ,
 wherein an oil reservoir in which oil is stored is formed in a sealed container including the fixed scroll and the orbiting scroll, a high-pressure area and a back-pressure chamber are formed on a rear surface of the orbiting scroll, an oil supplying passage through which the oil is supplied from the oil reservoir to the compression chamber passes through the back-pressure chamber, the oil supplying passage through which the back-pressure chamber communicates with the first compression chamber and the second compression chamber is provided at the position where the injection port is open to the first compression chamber and the second compression chamber during the compression stroke after the suction refrigerant is introduced and closed, and at least a partial section of an oil supplying section in which the oil supplying passage communicates with the first compression chamber or the second compression chamber overlaps with an opening section in which the injection port is open to the first compression chamber or the second compression chamber.   
     
     
         4 . The scroll compressor of  claim 2 ,
 wherein an oil reservoir in which oil is stored is formed in a sealed container including the fixed scroll and the orbiting scroll, a high-pressure area and a back-pressure chamber are formed on a rear surface of the orbiting scroll, an oil supplying passage through which the oil is supplied from the oil reservoir to the compression chamber passes through the back-pressure chamber, the oil supplying passage through which the back-pressure chamber communicates with the first compression chamber and the second compression chamber is provided at the position where the injection port is open to the first compression chamber and the second compression chamber during the compression stroke after the suction refrigerant is introduced and closed, and at least a partial section of an oil supplying section in which the oil supplying passage communicates with the first compression chamber or the second compression chamber overlaps with an opening section in which the injection port is open to the first compression chamber or the second compression chamber.   
     
     
         5 . The scroll compressor of  claim 3 , wherein an overlapping section where the oil supplying section overlaps with the opening section is defined as a partial section of the latter half of the oil supplying section. 
     
     
         6 . The scroll compressor of  claim 4 , wherein an overlapping section where the oil supplying section overlaps with the opening section is defined as a partial section of the latter half of the oil supplying section. 
     
     
         7 . The scroll compressor of  claim 1 , wherein at least one injection port is provided at a position where the injection port is sequentially open to the first compression chamber and the second compression chamber. 
     
     
         8 . The scroll compressor of  claim 1 , wherein as the injection port, a first injection port that is open only to the first compression chamber and a second injection port that is open only to the second compression chamber are provided, the first injection port has a larger port diameter than the second injection port, the opening section in which the first injection port is open to the first compression chamber is longer than the opening section in which the second injection port is open to the second compression chamber, or a pressure difference between an intermediate pressure in the first injection port and an internal pressure of the first compression chamber when the first injection port is open to the first compression chamber is more than a pressure difference between an intermediate pressure in the second injection port and an internal pressure of the second compression chamber when the second injection port is open to the second compression chamber.