Removable Pack for Reactivating a Turboshaft Engine, Architecture for a Multi-Engine System for Propelling a Helicopter, provided with such a Pack, and Corresponding Helicopter

Abstract

The invention relates to a removable reactivation pack for a turboshaft engine of a helicopter, comprising a gas generator equipped with a drive shaft, said turboshaft engine (6) being capable of operating in at least one standby mode during a stable flight of the helicopter, said removable pack comprising: a removable gearbox comprising a gearbox output shaft; controlled means for rotating said gearbox output shaft, referred to as reactivation means of said turboshaft engine; mechanical means for reversibly coupling said gearbox output shaft to said drive shaft of said gas generator.

Claims

1. A removable pack for the reactivation of a turboshaft engine of a helicopter, comprising a gas generator equipped with a drive shaft, said turboshaft engine being capable of operating in at least one standby mode during a stable flight of the helicopter, said removable pack comprising: a removable gearbox comprising a gearbox output shaft, controlled means for rotating said gearbox output shaft, referred to as reactivation means of said turboshaft engine, comprising at least: a first reactivation device that is mounted on said gearbox and comprises a shaft that is referred to as the first gearbox input shaft (34) and is mechanically connected to said gearbox output shaft, and controlled means for rotating said first gearbox input shaft, a second reactivation device that is mounted on said gearbox and comprises a shaft that is referred to as the second gearbox input shaft and is mechanically connected to said output shaft, and controlled means for rotating said second gearbox input shaft, mechanical means capable of reversibly coupling said gearbox output shaft to said drive shaft of said gas generator.

2. The pack according to claim 1, wherein said means for reversibly coupling said gearbox output shaft to said drive shaft of said gas generator are formed by an accessory gearbox of said turboshaft engine.

3. The pack according to claim 1, wherein said controlled means for rotating said first gearbox input shaft of said first reactivation device are capable of driving said first input shaft at a predetermined speed for a period that is less than the period required for said means for rotating said second input shaft of said second reactivation device to drive said second input shaft at a predetermined speed, said first reactivation device thus forming a device for rapid reactivation of said turboshaft engine, and said second reactivation device forming a device for normal reactivation of said turboshaft engine.

4. The pack according to claim 3, wherein said means for rotating said rapid reactivation device comprise a generator having a solid propellant, a pneumatic turbine that is connected to a pneumatic store, a hydraulic turbine that is connected to a hydropneumatic store, or an electrical machine that is connected to an electrical energy store.

5. The pack according to claim 1, wherein said removable gearbox comprises an intermediate shaft that carries a first intermediate pinion that is meshed with a ring gear carried by said first gearbox input shaft, and a second intermediate pinion that is meshed with a ring gear carried by said second gearbox input shaft, said gearbox output shaft being coupled to said second gearbox input shaft.

6. The pack according to claim 5, wherein said first intermediate pinion is mounted on said intermediate shaft by means of a free wheel that is designed and oriented so as to be able to rotate said intermediate shaft if said first input shaft is rotated.

7. The pack according to claim 1, wherein said removable gearbox comprises a sealed casing that comprises a lubrication opening in order to allow lubrication of the mechanisms of said removable gearbox.

8. The architecture of a propulsion system of a multi-engine helicopter comprising turboshaft engines connected to a power transmission gearbox wherein it comprises: at least one turboshaft engine from said turboshaft engines, referred to as a hybrid turboshaft engine, which is capable of operating in at least one standby mode during a stable flight of the helicopter, the other turboshaft engines operating alone during this stable flight, a removable turboshaft engine reactivation pack according to claim 1, which is mounted on said hybrid turboshaft engine so as to make it possible for said hybrid turboshaft engine to leave a standby mode on demand.

9. A helicopter comprising a propulsion system, wherein said propulsion system has an architecture according to claim 8.

Description

5. LIST OF DRAWINGS

[0046] Other aims, features and advantages of the invention will become apparent upon reading the following description, which is given purely by way of non-limiting example and relates to the accompanying drawings, in which:

[0047] FIG. 1 is a schematic view of a removable turboshaft engine reactivation pack according to an embodiment of the invention and mounted on a turboshaft engine,

[0048] FIG. 2 is another schematic view of a removable turboshaft engine reactivation pack according to an embodiment of the invention,

[0049] FIG. 3 is a schematic view of a helicopter comprising a turboshaft engine equipped with a reactivation pack according to an embodiment of the invention.

6. DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0050] In the drawings, the scales and the proportions are not respected for the sake of illustration and clarity.

[0051] FIG. 1 is a schematic view of a removable turboshaft engine reactivation pack 5 according to an embodiment of the invention and mounted on a turboshaft engine 6 of a helicopter.

[0052] Said turboshaft engine 6 comprises a gas generator 7 and a free turbine 8 that is rotated by the gases produced by the gas generator 7. For this purpose, the gas generator 7 comprises an air compressor 9 that is supplied with air by an air inlet (not shown in the drawings). The compressor 9 supplies a fuel, in the compressed air, to a combustion chamber 10, which fuel delivers burned gas that provides kinetic energy. Furthermore, a turbine 11 for partially expanding the burned gas is coupled to the compressor 10 by means of a drive shaft 12 so as to be able to rotate the compressor 10 and the equipment necessary for the operation of the gas generator or the helicopter. The resultant portion of the burned gas drives the free power transmission turbine 8 which is mechanically connected to a power transmission gearbox 22 by means of a free wheel 21.

[0053] The removable pack 5 for reactivating the turboshaft engine 6 comprises a removable gearbox 30 comprising a gearbox output shaft 31, a device 32 for rapid reactivation of the turboshaft engine 6 that is mounted on the gearbox 30, and a device 33 for normal reactivation of the turboshaft engine 6 that is mounted on the gearbox 30. The rapid reactivation device 32 further comprises a gearbox input shaft that is referred to as the first gearbox input shaft 34 and is mechanically connected to the output shaft 31 by means of a system of gears that is described in detail in relation to FIG. 2. The normal reactivation device 33 also comprises a gearbox input shaft that is referred to as the second gearbox input shaft 35 and is also connected to the gearbox output shaft 31 by means of a system of gears that is described in relation to FIG. 2.

[0054] The reactivation pack further comprises means for reversibly coupling the gearbox output shaft 31 to the drive shaft 12 of the gas generator 7. These means are formed by an accessory gearbox 14 of the turboshaft engine 6. In other words, the output shaft 31 can be coupled to/disconnected from a pinion 15 of the accessory gearbox 14 of the turboshaft engine 6.

[0055] A reactivation pack according to the invention can therefore be easily mounted on/removed from a turboshaft engine 6 depending on the requirements of the mission of the helicopter on which the turboshaft engine 6 is installed. Furthermore, the turboshaft engine 6 and the turboshaft engine reactivation devices 32, 33 are controlled by a dedicated inspection-control device, which is not shown in the drawings for reasons of clarity.

[0056] FIG. 2 is a detailed view of an architecture of the gearbox 30 and in particular of the system of gears mechanically connecting the input shaft 34 of the rapid reactivation device 32 and the input shaft 35 of the normal reactivation device 33 to the gearbox output shaft 31. The gearbox 30 comprises a casing 50 in which the system of gears is housed. Each reactivation device comprises a plate 62, 63 that is fixed to the casing 50 by screw/nut means, which are not shown in the drawings for reasons of clarity.

[0057] Said system of gears comprises the shaft 34 that is mounted on bearings 44 supported by the casing 50, and the shaft 35 that is mounted on bearings 45 supported by the casing 50. The shafts 34 and 31 are parallel and have a centre-to-centre distance that is, for example, less than 200 mm so as to form a compact gearbox that can be easily handled by an operator during operations for mounting/removing the pack. The shaft 34 further comprises a ring gear 54 that is meshed with a pinion 57 carried by an intermediate shaft 37. Said intermediate shaft 37 is mounted on bearings 47 of the casing 50. According to the embodiment in the drawings, the pinion 57 is mounted on the intermediate shaft 37 by means of a free wheel 25. The intermediate shaft 37 further comprises a pinion 58 that is meshed with the ring gear 55 of the shaft 35 connected to the normal reactivation device 33. The free wheel 25 is oriented such that a rotation of the shaft 34 causes a rotation of the intermediate shaft 37, which shaft itself rotates the shaft 35. In contrast, rotating the intermediate shaft 37 by means of the shaft 35 does not rotate the shaft 34. In this configuration, the free wheel 25 slides.

[0058] The casing 50 further comprises an opening 51 for lubricating the system of gears. This makes it possible to simultaneously lubricate the pinions, the ring gears and the free wheel of the system of gears.

[0059] Each reactivation device further comprises controlled means for rotating the gearbox input shaft to which said reactivation device is connected.

[0060] For example, the controlled means 32 for rotating the first gearbox input shaft 34 of the rapid reactivation device comprise a generator having a solid propellant, or a pneumatic turbine connected to a pneumatic store, or a hydraulic turbine connected to a hydropneumatic store, or an electrical machine connected to an electrical energy store. In general terms, these are means suitable for rapidly inducing the movement of said first gearbox input shaft 34 at a high rotational speed, for example of over 30,000 rotations/minute, in order to rapidly induce the movement of the gearbox output shaft 31 and thus rapidly reactivate the turboshaft engine 6 to which the reactivation pack is connected.

[0061] The controlled means 33 for rotating the second gearbox input shaft 35 of the rapid reactivation device comprise, for example, a starter/generator suitable for rotating the shaft at a speed of approximately 10,000 to 20,000 rotations/minute.

[0062] The invention also relates to an architecture of a propulsion system of a multi-engine helicopter, comprising turboshaft engines 6, 16 that are connected to a power transmission gearbox 22, as shown in FIG. 3. According to this architecture, a turboshaft engine 6 is equipped, by means of the accessory gearbox thereof, with a removable reactivation pack as described in relation to FIGS. 1 and 2.