Pitch change arrangement for a variable pitch fan
US4810164A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 12, 1987 |
| Grant date | Mar 7, 1989 |
| Priority date | — |
| Expiry date | Nov 12, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF05D2220/36
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A pitch arrangement for a variable pitch fan assembly of a turbofan gas turbine engine comprises a plurality of fan blades, each of which has a root portion rotatably mounted, in a thrust bearing on a fan rotor. A control ring is arranged coaxially with and is rotatably mounted on the fan rotor, and each of the fan blades is connected to the control ring by a lever arm. The pitch of the fan blades is varied by rotation of the control ring in either direction. A plurality of hydraulic rams are arranged to drive the control ring through a plurality of bell cranks. The hydraulic rams are mounted on the fan rotor so that the pistons and shafts move in a radial direction such that the centrifugal force of the pistons and shafts is applied to the bell cranks so that a counter turning movement is applied to the control ring to oppose the centrifugal turning moment of the fan blades.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.