Patent ID: 12203539

DETAILED DESCRIPTION

While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the disclosed subject matter.

FIG.1shows a turbomachine10of longitudinal axis X to which the disclosure applies. The turbomachine10shown here is a double-flow, double-body turbomachine designed to be mounted on an aircraft. Of course, the disclosure is not limited to this type of turbomachine.

In the present application, the terms “upstream”, “downstream”, “axial” and “axially” are defined with respect to the orientation of circulation of the gases in the turbomachine and also along the longitudinal axis (and even from left to right inFIG.1). The terms “radial”, “radially”, “internal”, and “external” are also defined with respect to a radial axis Z that is perpendicular to the axis X of the turbomachine.

This double-flow and double-body turbomachine10comprises a fan12that is mounted upstream of a gas generator or gas turbine engine14. The fan12comprises a plurality of fan blades16that extend radially from the periphery of a disc18through which a fan shaft20passes. The fan12is surrounded by a fan casing22centered on the longitudinal axis X. The fan casing22is supported by a nacelle24which extends around the gas generator14along the longitudinal axis X.

The gas generator14comprises, from upstream to downstream, a low-pressure (LP) compressor26, a high-pressure (HP) compressor28, a combustion chamber30, a high-pressure turbine32and a low-pressure turbine34. The rotor of the HP compressor28is connected to the rotor of the turbine32via an HP shaft36centered on the longitudinal axis to form a first body referred to as high-pressure body. The rotor of the LP compressor is connected to the rotor of the LP turbine via a LP shaft38centered on the longitudinal axis to form a second body referred to as low-pressure body. The LP shaft38extends inside the HP shaft36. The HP shaft36is a motor shaft, which is driven in rotation along the longitudinal axis X in an internal casing40centered on the longitudinal axis.

An air flux F entering the turbomachine via the fan12is divided by a splitter nose42of the turbomachine into a primary air flux P which passes through the gas generator3and in particular in a primary duct, and a secondary air flux S which circulates around the gas generator14in a secondary duct42. The primary duct44and the secondary duct42are coaxial. The secondary air flux S is ejected by a secondary nozzle46terminating the nacelle24, while the primary air flux P is ejected outside the turbomachine via an ejection nozzle48located downstream of the gas generator. The primary duct44is delimited at least partly, radially, by the internal casing40and by an inlet casing50. The secondary duct42is delimited at least partly, radially, by the inlet casing50and the fan casing. The inlet casing50supports the splitter nose42upstream and is extended downstream by an inter-duct casing52which supports the ejection nozzle48.

In an optional configuration, a speed reduction gear54can connect the LP shaft38to the fan shaft20, to allow the speed of the fan12to be reduced to a lower speed than that of the LP shaft38. The speed reduction gear54also allows a fan12with a large diameter to be arranged so as to increase the bypass ratio. The bypass ratio of the fan12is advantageously greater than 10. Preferably, the bypass ratio is between 15 and 20. The speed reduction gear can be either of planetary train or epicyclic train.

The turbomachine10comprises a substantially radial drive shaft56which is connected, on the one hand, to the high-pressure shaft36forming the main shaft of the turbomachine and, on the other hand, to an accessory gearbox58of the turbomachine. The drive shaft56extends substantially radially, i.e., at an angle of between 0° and 30° with respect to the radial axis Z, i.e., between 60° and 90° to the longitudinal axis X. This drive shaft enables the motor shaft, in this case the HP shaft36, to be driven in rotation so that the turbomachine can be started via an item of equipment or accessory cooperating with the accessory gearbox which will be described below.

In this example, the drive shaft56is referred to as a radial shaft because it extends substantially radially, being housed in a structural element of the turbomachine. This structural element extends substantially radially between the internal casing40and the fan casing and/or the nacelle24. The structural element is a casing arm60which structurally connects the internal casing40to the fan casing. At its end, the drive shaft56is received in a transfer gearbox62in which it is coupled by meshing with a transfer shaft64, with axis A substantially parallel to axis X, which is itself coupled to the accessory gearbox58.

The accessory gearbox58is located in a compartment of the nacelle24.FIG.2shows a known accessory gearbox58, which houses various items of equipment or accessories for the turbomachine.

This equipment, mounted on the gearbox58, may include fuel pumps, electric generators, a lubrication unit, a starter motor, hydraulic pumps, etc.

The gearbox58conventionally comprises a casing66defining an enclosure68housing here at least one gear train comprising a series of pinions, and more particularly here two gear trains70and72. The casing58comprises two substantially flat parallel side walls74and76opposite each other, between which are mounted support shafts for each of the pinions of the gear train.

The transfer shaft64, shown in part inFIG.2, draws or provides mechanical power to the HP shaft36. The transfer shaft64is coupled to the two gear trains70,72. The function of the two gear trains70,72thus described is to drive in rotation a plurality of separate accessories secured to the walls74,76. For example, in a non-limiting manner of the disclosure, these accessories comprise two electrical generators78,80for providing electrical power to the aircraft, an electric machine82for starting the engine or generating an electrical current, an electrical generator84for providing electrical current to or other engine equipment such as two hydraulic pumps86,88for providing pressurised oil to the engine and/or its equipment, a main oil pump90for providing lubricating oil to the oil circuits of the engine and/or its equipment, a main fuel pump92, and a centrifugal oil separator94, which is a passive member.

Of course, it will be understood that this arrangement is provided by way of example only and is not limiting of the disclosure and that an accessory gearbox58according to the disclosure may comprise a different number of accessories.

The side walls74,76therefore receive these accessories78,80,82,8486,88,90,92which each comprise a corresponding shaft passing through one of the walls74,76and which is coupled to a corresponding shaft78a,80a,82a,84a,86a,88a,90a,92asupporting one of the pinions78b,80b,82b,84b,86b,88b,90b,92bof one of the gear trains70or72. The transfer shaft64passes through the side wall76and is coupled to the shaft84supporting the pinion84bof the gear train70.

As shown inFIG.2, the side walls74,76delimit at least one internal volume96in the enclosure68, shown here in dotted lines, which surrounds a shaft82asupporting a pinion82b. This internal volume96is arranged on one side of the pinion82b.

As part of the hybridization of the accessory gearbox58, the disclosure proposes to take advantage of such an internal volume96in an accessory gearbox58to house therein an electric machine82. To this end, the electric machine surrounds the support shaft82aand the pinion82bis referred to as the hybridization pinion.

This configuration is shown schematically inFIG.3.

As before, the gearbox58houses an electric machine82comprising a rotor82cand a stator82d. However, unlike a gearbox58known in the art, the electric machine82is housed in the internal volume96.

More particularly, the rotor82cof the electric machine82is supported by the shaft82asupporting the hybridization pinion82bof the gear train70and the stator82dextends around the rotor82cand is mounted within the enclosure68in the internal volume96.

In the configuration shown here, the hybridization pinion82bis an intermediate pinion of the gear train70, but it will be understood that this arrangement does not limit the disclosure.

This configuration is particularly advantageous because it provides an electric machine82which is no longer secured to the side wall74but is integrated into the casing66. As a result, the gearbox58takes up less axial space along the axis A in the axis of the pinion82bof the gear train70. This configuration results in a gearbox70that takes up less space axially, which is particularly advantageous for a gearbox that needs to be positioned close to the central area of the turbomachine.

Alternatively (not shown), the integration of the electrical machine82inside the casing66enables the space previously used on the side face74to be freed up for positioning another accessory therein, thereby reducing the transverse dimensions of the gearbox58.

Another advantage of such an arrangement is that, because it is positioned in the casing66, the electric machine82can benefit from the internal lubrication of the casing66, which is necessarily already present due to the presence of the gear trains70,72.

FIG.4illustrates, in a non-limiting manner, an example of the mounting of such an electric machine82.

As can be seen, the shaft82aof the hybridization pinion82bis mounted so as to rotate in the casing66between two bearings98,100each supported by one of the side walls74,76. The shaft82acomprises a first section82a1which comprises the hybridization pinion82b, and which is arranged close to a first of the bearings, namely the bearing98. It comprises a second section82a2which extends between the hybridization pinion82band the opposite second bearing100. The rotor82cis attached to the second section82a2.

In the example shown here, the second section82a2of the shaft82ais in one piece with the first section82a1. The hybridization pinion82bis therefore also in one piece with the shaft82a.

The hybridization pinion82bcomprises a web82b1which has a diameter greater than the second section82a2of the shaft82aof the hybridization pinion82band which on its external periphery supports a meshing toothing82b2. A first face82c1of the rotor82cis received in abutment against this web82b1, and the rotor82cextends substantially axially from the web82b1towards the bearing100, and more particularly along a part of the second section82a2as far as an outer surface82c2of the rotor82cwhich is arranged in a recess from a free end82a4of the shaft82aand which receives an inner ring100aof the bearing100.

As a result, the hybridization pinion82b, the shaft82aand the rotor82ccan be assembled simply by slipping the rotor82cdirectly onto the shaft82a, abutting against the web82b1of the hybridization pinion82b. The bearing100is then mounted on the rotor82cand thus axially immobilises the rotor82cbetween the bearing100and the web82b1of the pinion82b.

It will be understood that rotational connection means will be interposed between an internal bore82c3of the rotor82cand the second section82a2of the shaft of the determined pinion82b.

The hybridization pinion82bcomprises a tubular section82b3which extends from its web82b1towards the adjacent side wall76and which comprises at its end a first end collar82b4receiving at least one inner ring98aof the bearing98.

The shaft82aof the hybridization pinion82bmay be solid but preferably, as shown inFIG.4, it is tubular and comprises a bore82a6which is coaxial with an orifice101formed in one of the adjacent side walls, here the wall74, the bore comprising internal splines82a7for coupling with a shaft of one of the accessories (not shown) secured to the adjacent wall74.

FIGS.5and6illustrate an optional configuration of the gearbox58comprising an additional electric machine83. As shown inFIG.5, an external face76bof one of the side walls, in this case the wall76, supports a tubular sheath102which can surround and be passed through by the transfer shaft64. The sheath102comprises an additional electric machine83which is mounted inside the sheath102. A stator83dof the additional electric machine82is secured in the sheath102and a rotor83cof the electric machine is secured to the transfer shaft64. The stator83dof the additional electric machine83is naturally mounted around the rotor83cof the additional electric machine.

As shown inFIG.6, the sheath102is secured to the side wall76of the accessory gearbox. It is also received in a sliding manner in a tubular sleeve63of the transfer gearbox, so as to absorb the functional clearances of the transfer gearbox62and the transfer shaft64when the transfer gearbox62is coupled to the gearbox58and to absorb the clearances resulting from the expansion of these parts during operation.

The mounting is therefore simplified, since all that needs to be done during the mounting is to secure the sheath102fitted with the stator83dto the accessory gearbox58, then secure the rotor83cto the transfer shaft64and finally insert the transfer shaft64fitted with its rotor83cinto the sheath102.

The disclosure therefore enables us to benefit from a turbomachine whose hybridization is achieved internally to the accessory gearbox, with a gearbox58that can be housed compactly close to the central area of the turbomachine.