GUIDE VANE ASSEMBLY FOR AUXILIARY POWER UNIT

摘要

A guide vane assembly for controllably varying fluid mass flow rates past compressor blades in an auxiliary power unit. The auxiliary power unit comprises a rotary apparatus for compressing fluid in a compressor housing wherein a plurality of compressor blades are mounted on a rotating hub. A fluid flow path extends through the housing which has a duct portion extending upstream of the compressor blades to an inlet plenum to define at least a portion of the fluid flow path. The guide vane assembly includes a central gear box adjacent the compressor housing which has a ring gear mounted for limited rotational movement. A plurality of guide vanes are disposed in the duct portion of the housing and are mounted for pivotal movement responsive to rotational movement of the ring gear. The guide vane assembly is adapted to convert rotation of the ring gear to pivotal movement of the guide vanes. The auxiliary power unit includes a worm gear for driving the ring gear to cause the limited rotational movement producing the pivotal movement of the guide vanes. With this arrangement, the central gear box completely seals all of the operating components including the ring gear and the worm gear in a lubricated environment isolated from ambient conditions.