Patent ID: 7195470
Filing Date: 2007-03-27
Classification: F04C,Y10S

Abstract:
1. A scroll type compressor comprising: a housing defining a discharge pressure region; a fixed scroll member having a fixed base plate and a fixed scroll wall extending from a surface of the fixed base plate; a movable scroll member having a movable base plate and a movable scroll wall extending from a surface of the movable base plate, the movable scroll wall being engaged with the fixed scroll wall, the fixed scroll member and the movable scroll member being arranged in the housing and defining therebetween a compression chamber, which moves radially and inwardly to progressively reduce the volume of the compression chamber for compressing gas by orbital motion of the movable scroll member; a first fixed wall provided in the housing for slidably supporting a surface of the movable scroll member; a back pressure chamber defined on a back surface side of the movable base plate in the housing; and a supply passage connecting the back pressure chamber to the discharge pressure region and passing through a sliding portion between the movable scroll member and the first fixed wall, wherein a clearance at the sliding portion varies in response to a position of the movable scroll member in a direction in which the movable scroll member approaches to or leaves from the first fixed wall, whereby cross-sectional area of the clearance where the gas passes is varied to adjust pressure in the back pressure chamber, the supply passage including a fixed passage, a communication recess and a movable passage, the communication recess and a region of an opening of the movable passage respectively functioning as a valve seat and a valve portion to open and close the supply passage.