Scroll compressor

A scroll compressor, comprising:

• a housing including a suction chamber configured to draw in fluid;
• a rotary shaft rotationally supported by the housing;
• a fixed scroll fixed to the housing;
• a movable scroll configured to orbit about a rotation axis of the rotary shaft as the rotary shaft rotates;
• an opposed wall located on an opposite side of the movable scroll from the fixed scroll and opposed to the movable scroll;
• and
• an annular plate arranged between the movable scroll and the opposed wall, wherein
• the fixed scroll includes:
• a fixed base plate;
• a fixed volute wall that extends from the fixed base plate;
• and
• a cylindrical fixed outer circumferential wall that extends from the fixed base plate and surrounds the fixed volute wall,
• the movable scroll includes:
• a movable base plate opposed to the fixed base plate;
• and
• a movable volute wall that extends from the movable base plate toward the fixed base plate and meshes with the fixed volute wall,
• the movable scroll is arranged on an inner side of the fixed outer circumferential wall,
• the opposed wall includes:
• an opposed surface opposed to the plate;
• an annular back-pressure-chamber-defining recess that is recessed from the opposed surface;
• and
• a back-pressure supplying groove that is recessed from the opposed surface,
• the plate includes a discharge hole that extends through the plate,
• the fixed outer circumferential wall, the movable scroll, and the plate define a suction pressure space configured such that the fluid flows from the suction chamber into the suction pressure space,
• the movable scroll and the opposed wall define a first back-pressure space,
• the plate and the back-pressure-chamber-defining recess define a second back-pressure space,
• the first back-pressure space and the second back-pressure space define a back-pressure chamber configured such that the fluid is drawn into the back-pressure chamber to urge the movable scroll toward the fixed scroll,
• the back-pressure supplying groove is configured to connect the first back-pressure space to the second back-pressure space, thereby supplying the fluid from the first back-pressure space to the second back-pressure space,
• the discharge hole is configured to connect the second back-pressure space to the suction pressure space, thereby discharging the fluid from the second back-pressure space to the suction pressure space, and
• at least part of the discharge hole is overlapped with the back-pressure supplying groove in an axial direction of the rotary shaft.