DOC AIRBUS | AMM A320FACCESSORY DRIVE GEARBOX - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The cast-aluminum accessory-drive gearbox (referred to as the gearbox) supplies the drive pads for the Auxiliary Power Unit (APU) generator and accessories which include:
** ON A/C NOT FOR ALL The cast-aluminum accessory-drive gearbox (referred to as the gearbox) supplies the drive pads for the Auxiliary Power Unit (APU) generator and accessories which include:
- the starter motor assembly,
- the oil pump assembly,
- the fuel control assembly,
- the cooling-air fan assembly.
2. Description
A flanged joint attaches the gearbox to the load compressor. The APU gives a direct drive to the gearbox. The APU forward side mounts are part of the gearbox structure, which is also an oil reservoir (for the wet-sump lubrication system) (Ref. AMM D/O 49-90-00-00). The capacity of the oil reservoir (gearbox) is 5.4 l (1.43 USgal).
The gravity fill port is part of the gearbox housing. A direct-reading sight glass, installed adjacent to the gravity fill port, gives a visible oil-level indication. An oil level sensor, installed in the sump, gives a low oil-level signal to the Electronic Control Box (ECB) 59KD (Ref. AMM D/O 49-93-00-00) if the oil in the reservoir has decreased to 3.9 l (1.03 USgal) or less.
Air/oil mist is vented to the APU exhaust through a passage in the gearbox housing downstream of te air-oil separator.
A vane type pressure pump provides the pressurized oil for lubrication and generator cooling. A non-adjustable, spring loaded pressure relief valve is installed on the lower front face of the gearbox. It is set to open when the oil pump pressure exceeds 4.5 to 5.2 bar (66 to 76 p.s.i.).
The accessory drive gearbox is a module. You can remove it complete from the APU, which lets all the gears, bearings and seals remain in position.
A flanged joint attaches the gearbox to the load compressor. The APU gives a direct drive to the gearbox. The APU forward side mounts are part of the gearbox structure, which is also an oil reservoir (for the wet-sump lubrication system) (Ref. AMM D/O 49-90-00-00). The capacity of the oil reservoir (gearbox) is 5.4 l (1.43 USgal).
Accessory Drive GearboxThe gravity fill port is part of the gearbox housing. A direct-reading sight glass, installed adjacent to the gravity fill port, gives a visible oil-level indication. An oil level sensor, installed in the sump, gives a low oil-level signal to the Electronic Control Box (ECB) 59KD (Ref. AMM D/O 49-93-00-00) if the oil in the reservoir has decreased to 3.9 l (1.03 USgal) or less.
Air/oil mist is vented to the APU exhaust through a passage in the gearbox housing downstream of te air-oil separator.
A vane type pressure pump provides the pressurized oil for lubrication and generator cooling. A non-adjustable, spring loaded pressure relief valve is installed on the lower front face of the gearbox. It is set to open when the oil pump pressure exceeds 4.5 to 5.2 bar (66 to 76 p.s.i.).
The accessory drive gearbox is a module. You can remove it complete from the APU, which lets all the gears, bearings and seals remain in position.