| 摘要 |
A scroll fluid displacement apparatus with improved tangential and radial sealing means is disclosed. The apparatus comprises scroll members including meshing involutes which are angularly offset such that they define one or more moving fluid pockets of variable volume as well as a theoretical eccentric separating the involute axes. Tangential and radial sealing is preferably provided by a drive shaft which provides both radial and axial load forces between the involutes. The drive shaft separates the involute centers by a distance not equal to the theoretical eccentric thereby causing the involutes to maintain a radial contacting relationship with each other for effective tangential sealing. Radial sealing is attained by withdrawing a portion of fluid from the fluid pocket of highest pressure for pressurizing a chamber within the drive shaft. The pressure acts against a piston engaging a scroll member which is adapted for axial movement, thereby generating radial sealing forces. The involutes have tips with recessed portions therein for accelerated initial surface wear and improved radial sealing. Idler crank assemblies having axial compliance are provided to maintain the desired angular relationship between the scroll members. In one alternative embodiment, the idler crank assemblies provide for tangential sealing by separating the involute centers by a distance not equal to the theoretical eccentric.
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