Scroll compressor

A scroll compressor, comprising:

• a casing;
• a rotation shaft that comprises a first eccentric portion and a second eccentric portion which are spaced apart from each other in an axial direction;
• a first compression part that is coupled to the first eccentric portion of the rotation shaft to form a first compression chamber;
• a second compression part that is disposed on one axial side of the first compression part and coupled to the second eccentric portion of the rotation shaft to form a second compression chamber;
• and
• a main frame that comprises a shaft receiving portion disposed between the first compression part and the second compression part such that the rotation shaft penetrates therethrough, wherein at least one of the first compression part or the second compression part comprises a capacity varying part configured to idle the corresponding compression part by inducing refrigerant leakage from a compression chamber or block refrigerant suction into the corresponding compression chamber, wherein the first compression part comprises a first orbiting scroll configured to orbitally move while being axially supported with a first back pressure chamber defined together with a first side surface of the main frame, and a first fixed scroll engaged with the first orbiting scroll to form the first compression chamber, wherein the second compression part comprises a second orbiting scroll configured to orbitally move while being axially supported with a second back pressure chamber defined together with a second side surface of the main frame, and a second fixed scroll engaged with the second orbiting scroll to form the second compression chamber, wherein the capacity varying part comprises:
• a communication hole disposed in the first orbiting scroll such that the first compression chamber and the first back pressure chamber communicate with each other;
• and
• a first valve disposed to open and close the communication hole to allow refrigerant movement from the first compression chamber to the first back pressure chamber while blocking refrigerant movement from the first back pressure chamber to the first compression chamber, and wherein the first valve is formed such that a cross-section on a side toward the main frame is smaller than a cross-section on a side toward the first orbiting scroll.