DOC AIRBUS | AMM A320FMAIN GEARBOX ASSEMBLY - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Main Gearbox (MGB)
(1) The function of the MGB is to supply torque to the oil, fuel and hydraulic system components connected to the MGB. The MGB is supplied torque by the High Pressure Compressor (HPC) and the Angle Gearbox (AGB).
(2) The MGB housing is installed below the HPC and contains ball and roller bearings, carbon seals and gear shafts which connect the different system components. The deoiler is an internal component of the MGB and removes oil from lubrication breather mixtures. There is an opening to turn the N2 system with your hand so that the HPC and the High Pressure Turbine (HPT) rotors can be inspected. In the MGB, oil lubricates the ball and roller bearings and the gear shafts. The oil is supplied to the MGB housing from an external oil supply tube. Scavenge oil that exits the MGB is sent to the oil tank by the lubrication and scavenge pump. The MGB uses internal casting openings as much as possible to supply oil to the different bearings and components and to supply fuel to different components. This makes many external tubes not necessary and decreases the risk of leakage.
Main Gearbox (MGB) ModuleA. The HPC/HPT rotors supply torque to the MGB.
(1) This is done with a gearbox drive shaft in the Compressor Intermediate Case (CIC) which engages the No. 3 bearing bevel gear on the front end of the HPC.
B. The HPC/HPT rotational speed (N2) is decreased with a sequence of gear sets along the gear box drive train from the tower shaft area through the AGB to the MGB.
(1) This decreased shaft speed and increased torque is used in the MGB to turn the components of the electrical, fuel, oil, hydraulic and starter systems.
C. A crank port is supplied at the rear of the MGB housing to make it possible to turn the HPC/HPT rotors when necessary for repair or inspection.
(1) The crank port can be used for borescope inspection to troubleshoot the internal parts of the MGB.