Patent GB-1293787-A (GB)
Title: Gas turbine engine
IPC: F02C7/32
Filed: 1971-04-19
Abstract: 1293787 Gas turbine engines - mounting auxiliaries AVCO CORP 19 April 1971 [28 Sept 1970] 26342/71 Heading F1G The invention relates to a gas turbine engine in which a gear casing is provided, the gear casing having an upper cover disposed in a horizontal plane, means being provided for mounting accessories on the upper cover whereby mounting and dismounting of the accessories is facilitated. The engine shown comprises LP compressor 21, HP compressor 22, air preheater 26, combustion system 28, HP turbine 43 which drives HP compressor 22 through shaft 45, LP turbine 44 which drives LP compressor 21 through shaft 46, and a separate power turbine 48 which drives through shaft 50 and gearing 51 a transmission system 54 for example of a land vehicle. The combustion system comprises a tangentially directed flame tube having a fuel injector 36 and an outlet volute 38. An accessory gear casing 60 is mounted below the compressor assembly and comprises a lower casing 62 and an upper cover 64 which is disposed in a horizontal plane and which is formed at its upper surface with pads on which engine accessories and vehicle auxiliaries are mounted and driven by gearing within the gear casing. The gearing comprises an input pinion 66 which is driven from the HP compressor 22 by bevel gearing 96, 94, shaft 90 and shaft 78, the shaft 90 being in splined engagement 86 with the shaft 78, and the shaft 78 being in splined engagement 77 with the pinion 66, the pinion being rotatably mounted in bearings 68, 70 carried by the cover 64 and the lower casing 62 respectively. The pinion 66 engages an idler gear and drives further gears 104, 106, 110, 112, 114 and 104, 108, 116, 120, 122, the gears 106, 114, 108, 118 and 120 being formed with internal gears 122 whereby various accessories are driven. The gear 108 for example is shown in Fig.7 with its internal gear 122. The alternator or generator 69 comprises an input pinion 129 which upon assembly engages internal gear 122 whereby the alternator is driven. The alternator is formed at its lower end with a mounting flange 134 which is mounted on a pad 124 of the cover 64 of the gear casing which is disposed in a horizontal plane, the alternator being secured by an assembly of studs 126 and nuts. The other accessories such as fuel pump 57, primary starter 61, auxiliary emergency starter 63 and hydraulic pump 67, are mounted and driven in a similar manner. The oil pump 65 is mounted as shown in Fig.6, its drive pinion 112 engaging the gear 110, the pump being located in a recess formed in the lower casing 62. The pump inlet assembly 144 extends into a sump 146 formed in the casing 62. The gear casing is located and secured to the lower portion of the combustion system casing 28 by means of flanges 150 formed on the casing 28 which are received between lugs 154 formed on the gear casing, pins 152 extending through the flanges and lugs as shown. The forward end of the gear casing is mounted on the compressor casing 22 by means of a pin 160 which extends through a bore formed in the gear casing cover 64 and through a bracket 166 secured to the compressor casing.