DRIVE POSITIONING MECHANISM WITH BACKLASH ADJUSTMENT FOR VARIABLE PIPE DIFFUSER

摘要

A drive positioning mechanism with backlash adjustment for use in a variable pipe diffuser for a centrifugal compressor. A rotational drive means is fixedly attached to the housing of a centrifugal compressor with a pinion gear mounted thereto. A rack gear is mounted to the inner ring and adapted to engage in meshing arrangement with the pinion gear. The rotational drive means is operable to position the inner ring between a fully open position and a partially closed position. A travel limiter is provided to positively limited the travel of the inner ring at the fully open and the partially closed positions. The backlash adjustment mechanism is comprised of a housing having a cylindrical body positioned concentrically about a first centerline and having a bore disposed axially though the body positioned about a second centerline. The drive shaft is rotatably disposed concentric with the second centerline within the bore. The inner ring is positioned such that it meshes with the pinion gear. The housing is disposed within the casing and is rotatably operable to effect an adjustment of the backlash between the pinion gear and the rack gear.