Scroll compressor including communication hole with improved back pressure chamber and back pressure hole locations

A scroll compressor, comprising:

• a case;
• a fixed scroll and an orbiting scroll installed in the case, the fixed scroll defining a communication hole therethrough and including a bottom surface, the communication hole having an inlet disposed at an upper surface of the fixed scroll adjacent a discharge space that directly opens out to the discharge space and an outlet disposed at the bottom surface, the orbiting scroll including:
• a wrap portion including a surface and engaged with the fixed scroll so as to form a plurality of compression chambers therebetween, the surface of the orbiting scroll facing toward the bottom surface of the fixed scroll and the wrap portion being configured to form a thrust bearing surface together with the fixed scroll where the surface of the orbiting scroll engages the bottom surface of the fixed scroll;
• and
• a base portion coupled to the wrap portion and configured to be moveable toward the fixed scroll to support the wrap portion, a back pressure chamber is formed between the base portion and the wrap portion, and the scroll compressor further comprising:
• a drive motor including a crank shaft coupled to the base portion, at a side of the base portion opposite a side thereof at which the wrap portion is coupled wherein the drive motor is configured to eccentrically rotate the base portion and the wrap portion;
• a main frame installed in the case, wherein the main frame supports the base portion in an axial direction;
• the discharge space defined by an inner wall surface of the case and the upper surface of the fixed scroll, wherein refrigerant and oil discharged from the plurality of compression chambers are received in the discharge space;
• and
• the communication hole provides fluid communication of at least one of the oil or the refrigerant from the discharge space through the inlet to the outlet of the communication hole such that:
• (i) the oil in the discharge space flows from the discharge space to the thrust bearing surface through the outlet of the communication hole when the surface of the wrap portion of the orbiting scroll engages the bottom surface of the fixed scroll and a levitation of the wrap portion occurs due to the back pressure applied from the back pressure chamber so that the oil disposed on the thrust bearing surface provides lubrication for the fixed scroll and the orbiting scroll during operation of the fixed scroll, and
• (ii) if a suction side of the scroll compressor is blocked during the operation of the scroll compressor such that the back pressure of the back pressure chamber decreases such that the surface of the orbiting scroll disengages from the bottom surface of the fixed scroll the refrigerant in the discharge space flows through the communication hole and through the outlet and into the plurality of compression chambers to prevent a high vacuum state of the plurality of compression chambers from occurring,
• wherein if a line that connects a geometric center of the orbiting scroll with a rotational center of the crank shaft is defined as a first virtual line and a line perpendicular to the first virtual line and passing through the geometric center of the orbiting scroll is defined as a second virtual line and the first virtual line and the second virtual line are respectively disposed in a plane transverse to a rotational axis of the crank shaft, the geometric center of the back pressure chamber as extended in to the plane is eccentrically located from the geometric center of the orbiting scroll as extended in to the plane within a range of about ±30° from the second virtual line within the plane.