POWER TRANSMISSION IN AN AIRCRAFT TURBOMACHINE

Abstract

A turbomachine assembly (110) for an aircraft, this assembly having a longitudinal axis (A) and comprising a power transmission system (134) on a rotating body (16), this system (134) comprising three shafts (136, 142, 144) coupled together by bevel gears (146, 148, 150), and equipment (140) being located radially inside the gas generator (12) and coupled to one of these shafts (144). Figure 2

Description

Title of the invention: POWER TRANSMISSION IN AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to the transmission of power in an aircraft turbomachine. Technical background

[0002] The state of the art includes in particular document WO-A1-2012 / 114029A1.

[0003] As schematically illustrated in [Fig.l], an aircraft turbomachine 10 has a longitudinal axis A and comprises a gas generator 12 surrounded by a casing 14.

[0004] The gas generator 12 extends along the axis A and comprises at least one rotating body 16 comprising a compressor rotor 18 connected by a shaft 20 to a turbine rotor 22.

[0005] In the example shown, the turbomachine 10 is a twin-spool, twin-flow turbojet, the turbomachine 10 comprising two rotating bodies, respectively low pressure 16b and high pressure 16a.

[0006] With reference to the flow of gases in the turbomachine 10, the gas generator 12 comprises from upstream to downstream a low pressure compressor 18a, a high pressure compressor 18b, an annular combustion chamber 24, a high pressure turbine 22a and a low pressure turbine 22b.

[0007] The rotors of the high pressure compressor 18a and the high pressure turbine 22a are connected together by a high pressure shaft 20a to form a high pressure body 16a. The rotors of the low pressure compressor 18b and the low pressure turbine 22b are connected together by a low pressure shaft 20b to form a low pressure body 16b. The low pressure body 16b is further connected to a propeller which is surrounded by the casing 14 and which is commonly called a fan 28.

[0008] The blower 28 generates an air flow F in operation which is divided downstream of the blower 28 into a primary flow F1 and a secondary flow F2, the primary flow F1 flowing in a primary annular vein VI which is located in the gas generator 12 and which successively passes through the compressors 18b, 18a, the combustion chamber 24 and the turbines 22a, 22b.

[0009] The secondary flow F2 flows in a secondary annular vein V2 which is delimited by an external annular casing 28 of the gas generator 12 and the casing 14 which extends around this casing 28.

[0010] The casing 14 is generally connected to the gas generator 12 by tubular arms 30 which extend radially through the vein V2.

[0011] It is known to take mechanical power from one of the rotating bodies 16 of the turbomachine to power equipment or accessories such as an accessory box 32 commonly called AGB (acronym for Accessory GearBox).

[0012] The accessory box 32 is relatively bulky and is generally positioned radially outside the casing 14, in a nacelle (not shown) which surrounds the casing 14 and the gas generator 12.

[0013] [Fig.l] shows a power transmission system 34 coupled to the high pressure body 16a.

[0014] The transmission system 34 comprises a shaft 36 which crosses the second vein V2 by passing through one of the arms 30. This shaft 36 comprises a radially internal end 36a located radially inside the casing 28 and coupled to the high-pressure body 16a, and a radially external end 36b located radially outside the casing 14 and coupled to the accessory box 32.

[0015] It has already been proposed to integrate equipment into the gas generator 12, radially inside the casing 28 and to couple it to the transmission system 34.

[0016] In the current technique, the solutions are applicable only in the case where the transmission shaft 36 extends radially inward in a straight line to the high pressure body 16a. However, some gas generators 12 have an architecture which prevents a direct connection of this type and requires an angle transmission inside the casing 28.

[0017] In this case, current solutions are not feasible. Indeed, even if an attempt were made to integrate an accessory inside the casing 28 and at the end of the shaft 36, this accessory would be too bulky and its angular positioning would not allow it to function correctly (it would have too great an inclination for its internal lubrication circuit, for example).

[0018] The invention provides a solution to at least some of the problems of the prior art, which is simple, effective and economical. Summary of the invention

[0019] The invention relates to a turbomachine assembly for an aircraft, this turbomachine assembly having a longitudinal axis and comprising:

[0020] - a gas generator extending along the axis and comprising at least one body rotating and an annular envelope that extends around and along the axis,

[0021] - an annular casing which extends around the gas generator, and

[0022] - a power transmission system coupled to the rotating body, this system comprising a first shaft which comprises a radially inner end located ra- dially inside the casing and capable of being coupled to said rotating body, and a radially external end located radially outside the casing, and

[0023] - a first equipment or first set of equipment located radially to outside the casing and coupled to the radially outer end of the first shaft,

[0024] characterized in that the transmission system further comprises:

[0025] - a second shaft which is located radially inside the casing and which comprises a radially inner end coupled to the rotating body, and a radially outer end,

[0026] - a third shaft which is located radially inside the casing and which comprises first and second longitudinal ends,

[0027] the radially inner end of the first shaft, the radially outer end of the second shaft, and the first end of the third shaft being coupled together by bevel gears,

[0028] and in that a second equipment or second set of equipment is located radially inside the casing and coupled to the second end of the third shaft.

[0029] The invention thus proposes a solution for drawing power and supplying power to one or more accessories housed inside the gas generator. For this, two additional shafts and bevel gears are used and are housed inside the casing of the gas generator.

[0030] In addition to the first shaft extending through the secondary vein, the transmission system includes a second shaft coupled to the rotating body, and a third shaft coupled to a second equipment or set of equipment.

[0031] The use of bevel gears for coupling these shafts radially inside the casing allows the third shaft to have a relatively axial orientation and therefore facilitates the integration and positioning of the second equipment in this area.

[0032] The turbomachine according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another:

[0033] — the rotating body comprises a compressor rotor connected by a shaft to a rotor of turbine, the gas generator comprising a first flow vein of a primary flow along the axis;

[0034] — the annular casing delimits with said envelope a second flow vein a secondary flow along the axis;

[0035] — the first tree crosses the second vein;

[0036] — each of the shafts includes or carries a bevel gear, so the coupling of the shafts are provided by a conical trio, which is advantageous in terms of space requirements in particular; - the second equipment or set of equipment is chosen from a motor, a generator, a motor-generator, a starter and a gearbox; the gearbox can drive one or more electrical, pneumatic and / or hydraulic equipment; in engine mode, a motor-generator or a starter can for example provide power when starting the turbomachine and / or provide additional power during takeoff for example; the second accessory can therefore recover or transmit power via the bevel gears; - the radially inner end of the first shaft is interposed between the radially outer end of the second shaft and the first end of the third shaft, the radially inner end of the first shaft carrying a bevel gear which is meshed with bevel gears carried respectively by the radially outer end of the second shaft and by the first end of the third shaft; - the radially inner end of the first shaft is guided in rotation by bearings mounted directly on the radially outer end of the second shaft and the first end of the third shaft; the use of bearings, in particular rolling bearings, is optional but can allow easier assembly and an optimized operating mode at the level of the contact of the teeth of the pinions; these bearings can be preloaded bearings; - the radially outer end of the second shaft is interposed between the radially inner end of the first shaft and the first end of the third shaft, the radially outer end of the second shaft carrying a bevel gear which is meshed with bevel gears carried respectively by the radially inner end of the first shaft and by the first end of the third shaft; - the radially outer end of the second shaft is guided in rotation by bearings mounted directly on the radially inner end of the first shaft and the first end of the third shaft; the use of bearings, in particular rolling bearings, pre-loaded is optional but can allow easier assembly and an optimized operating mode at the level of the contact of the teeth of the pinions.;

[0037] - the first shaft is inclined relative to the axis by an angle a of between 10 and 80°, and / or the second shaft is inclined relative to the axis by an angle [3 of between 10 and 80°, and / or the third shaft is inclined relative to the axis by an angle y of less than 20° in absolute value and preferably less than 10°; the second accessory can thus be positioned in a direction substantially parallel to the main axis of the turbomachine, but can also be inclined according to the constraints of size and design of the bevel gears; - the bevel gears are chosen from straight bevel gears, spiral bevel gears or hypoid bevel gears; the module, the pressure and helix angles, the number of teeth of each of the gears are defined according to the usage needs and the required mechanical strength; - the first equipment or set of equipment is an accessory or gear box which extends around a part of the casing; - the first equipment or set of equipment is coupled to the radially external end of the first shaft by an angle transmission device;

[0038] — the rotating body is a high pressure body or a low pressure body;

[0039] — the first and second shafts form an angle between them of between 10 and 80°, and / or the first and third shafts form an angle between them of between 10 and 80°, and / or the second and third shafts form an angle between them of between 10 and 80°. Brief description of the figures

[0040] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0041] [Fig-1] [Fig.l] is a schematic axial sectional view of a turbomachine aircraft;

[0042] [Fig.2] [Fig.2] is a schematic axial sectional view of a turbomachine aircraft according to one embodiment of the invention;

[0043] [Fig.3] [Fig.3] is an enlarged schematic view of a part of [Fig.2] and illustrates in particular the bevel gears for coupling the shafts of the power transmission system; and

[0044] [Fig.4] [Fig.4] is a schematic perspective view of a turbomachine aircraft according to an alternative embodiment of the invention. Detailed description of the invention

[0045] [Fig.l] has been described in the above.

[0046] Reference is made to Figures 2 and 3 which illustrate a first embodiment of a turbomachine assembly 110 according to the invention.

[0047] The turbomachine assembly 110 has a longitudinal axis A and comprises:

[0048] - a gas generator 12 which extends along the axis A. The gas generator comprises a first flow vein VI of a primary flow Fl along the axis A, and an annular envelope 28 which extends around and along the axis A and the vein VI,

[0049] - an annular casing 14 which extends around the gas generator 12; the casing annular 14 delimits with the envelope 28 a second vein V2 of flow of a secondary flow F2 along the axis A, and

[0050] - a power transmission system 134 coupled to a rotating body 16 of the turbomachine assembly.

[0051] In the example shown, the turbomachine assembly 110 is a twin-spool, twin-flow turbojet, the turbomachine assembly 110 comprising two rotating bodies, respectively low pressure 16a and high pressure 16b.

[0052] With reference to the flow of gases in the turbomachine assembly 110, and as can be seen in [Fig.l], the gas generator 12 comprises from upstream to downstream a low pressure compressor 18b, a high pressure compressor 18a, an annular combustion chamber 24, a high pressure turbine 22a and a low pressure turbine 22b.

[0053] The rotors of the high pressure compressor 18a and the high pressure turbine 22a are connected together by a high pressure shaft 20a to form a high pressure body 16a. The rotors of the low pressure compressor 18b and the low pressure turbine 22b are connected together by a low pressure shaft 20b to form a low pressure body 16b. The low pressure body 16b is further connected to a propeller which is surrounded by the casing 14 and which is commonly called a fan 28.

[0054] The blower 28 generates an air flow F in operation which divides downstream of the blower 28 to form the primary flow F1 and the secondary flow F2. The primary flow F1 flows in the primary annular vein VI which successively passes through the compressors 16b, 16a, the combustion chamber 24 and the turbines 22a, 22b. The secondary flow F2 flows in the secondary annular vein V2.

[0055] The casing 14 is connected to the gas generator 12 by tubular arms 30 which extend radially through the vein V2 and are partially shown in [Fig.2],

[0056] [Fig.2] shows an embodiment of a power transmission system 134 coupled to the high pressure body 16a of the turbomachine.

[0057] The transmission system 134 comprises:

[0058] - a first shaft 136 which comprises a radially internal end 136a located radially inside the casing 28, and a radially external end 136b located radially outside the casing 14; the first shaft 136 crosses the second vein V2,

[0059] - a first equipment 140 or first set of equipment located radially at the outside of the casing 14 and coupled to the radially external end 136b of the first shaft 136,

[0060] - a second shaft 142 which is located radially inside the casing 28 and which comprises a radially inner end 142a coupled to the rotating body 16, and a radially outer end 142b, and

[0061] - a third shaft 144 which is located radially inside the casing 28 and which comprises first and second longitudinal ends 144a, 144b.

[0062] According to the invention, the radially inner end 136a of the first shaft 136, the radially outer end 142b of the second shaft 142, and the first end 144a of the third shaft 144 are coupled together by bevel gears 146, 148, 150 ([Fig.3]).

[0063] Furthermore, a second equipment or second set of equipment 152 is located radially inside the casing 28 and coupled to the second end 144b of the third shaft 144.

[0064] The first equipment or set of equipment 140 is an accessory box in the example shown. This accessory box, commonly called AGB (acronym for Accessory GearBox), is positioned radially outside the casing 14, in a nacelle (not shown) which surrounds the casing 14 and the gas generator 12.

[0065] The accessory box may have an elongated and curved shape to follow the cylindrical shape of the housing 14, as illustrated in [Fig. 3]. The box may extend around this housing 14 at a predetermined angle. Several accessories may be mounted on the accessory box, such as for example a starter, a motor, a generator, a motor-generator, a pump, a lubrication unit, etc.

[0066] The accessory box or equipment 140 may comprise internal gears ensuring the mechanical connection of the shaft 136 to the various accessories and in particular the mechanical drive of the shafts of these accessories.

[0067] The accessory box or equipment 140 can be coupled to the radially outer end 136b of the first shaft 136 by an angle transmission device 160.

[0068] The second equipment 152 or set of equipment can be chosen from a starter, a motor, a generator, a motor-generator, a pump, a lubrication group, a second AGB accessory box, etc.

[0069] In the exemplary embodiment of Figures 2 and 3, the radially inner end 136a of the first shaft 136 is interposed between the radially outer end 142b of the second shaft 142 and the first end 144a of the third shaft 144.

[0070] The radially inner end 136a of the first shaft 136 carries a bevel gear 146 which is meshed with bevel gears 148, 150 carried respectively by the radially outer end 142b of the second shaft 142 and by the first end 144a of the third shaft 144.

[0071] The first shaft 136 can be inclined relative to the axis A by a (smaller) angle a between 10 and 80°.

[0072] The second shaft 142 can be inclined relative to the axis A by a (smaller) angle [3 of between 10 and 80°.

[0073] The third shaft 144 may be inclined relative to the axis A by a (smaller) angle y of less than 20° and preferably less than 10°. This shaft 44 is thus substantially parallel to the axis A.

[0074] The first and second shafts 136, 142 can form between them a (smaller) angle XI of between 10 and 80°.

[0075] The first and third shafts 36, 44 can form between them a (smaller) angle X2 of between 10 and 80°.

[0076] The bevel gears 146, 148, 150 are preferably chosen from straight bevel gears, spiral bevel gears or hypoid bevel gears. The module, the pressure and helix angles, the number of teeth of each of the gears are defined according to the usage needs and the required mechanical strength;

[0077] In the example shown, the pinions 148, 150 are similar and comprise a spiral-bevel toothing on a cylindrical body secured to the end 142b, 144a of the corresponding shaft 142, 144. The pinion 146 comprises a spiral-bevel toothing formed at the outer periphery of an annular web 162 which is also spiral-bevel, the inner periphery of which is connected to a cylindrical body secured to the end 136a of the shaft 136.

[0078] Each of the shafts 136, 142, 144 is guided in rotation by bearings, preferably three in number per shaft.

[0079] Each of the shafts 136, 142, 144 is thus guided by:

[0080] - two bearings 164, 166, respectively ball and roller bearings for example, mounted around an axial end of the body of this shaft, and

[0081] - another bearing 168, preferably roller bearing, mounted around an axial end opposite of the body.

[0082] The inner rings of these bearings 164, 166, 168 are located on the shafts or bodies to be guided. The outer rings of the bearings 164, 166, 168 are connected to a casing, with the exception of the outer rings of the bearings 164, 166 of the shafts 142, 144 which are connected to the bodies of the first shaft 136 and in particular to the web 162.

[0083] These bearings 164, 166, 168 can be replaced by pre-loaded bearings.

[0084] In the embodiment variant of [Fig.4], the radially external end 142b of the second shaft 142 is interposed between the radially internal end 136a of the first shaft 136 and the first end 144a of the third shaft 144.

[0085] The radially external end 142b of the second shaft 142 carrying a bevel gear 148 which is meshed with bevel gears 146, 150 carried respectively by the radially internal end 136a of the first shaft 136 and by the first end 144a of the third tree 144.

[0086] The first shaft 136 can be inclined relative to the axis A by an angle of between 10 and 80°.

[0087] The second shaft 142 can be inclined relative to the axis A by an angle between 10 and 80°.

[0088] The third shaft 144 may be inclined relative to the axis A by an angle of less than 20° in absolute value and preferably less than 10°. This shaft 44 is thus substantially parallel to the axis A.

[0089] The first and second shafts 136, 142 may form an angle between them of between 10 and 80°.

[0090] The second and third shafts 142, 144 can form an angle between them of between 10 and 80°.

[0091] The shafts 136, 142, 144 may be guided by bearings as discussed above with reference to [Fig. 3]. The end 142b of the shaft 142 of [Fig. 4] is then similar to the end 136a of the shaft 136 of [Fig. 3], and the ends 136a, 144a of the shafts 136, 144 of [Fig. 4] are then similar to the ends 142b, 144a of the shafts 142, 144 of [Fig. 3].

[0092] These bearings 164, 166, 168 can be replaced by pre-loaded bearings.

Claims

Claims

1. A turbomachine assembly (110) for an aircraft, said turbomachine assembly (110) having a longitudinal axis (A) and comprising: - a gas generator (12) extending along the axis (A) and comprising at least one rotating body (16) and an annular casing (28) which extends around and along the axis (A), - an annular casing (14) which extends around the gas generator (12), and - a power transmission system (134) coupled to the rotating body (16), this system (134) comprising a first shaft (136) which comprises a radially internal end (136a) located radially inside the casing (28) and capable of being coupled to said rotating body (16), and a radially external end (136b) located radially outside the casing (14), and - a first equipment (140) or first set of equipment located radially outside the casing (14) and coupled to the radially external end (136b) of the first shaft (136), characterized in that the transmission system (134) further comprises: - a second shaft (142) which is located radially inside the casing (28) and which comprises a radially internal end (142a) coupled to the rotating body (16), and a radially external end (142b), - a third shaft (144) which is located radially inside the casing (28) and which comprises first and second longitudinal ends (144a, 144b), the radially inner end (136a) of the first shaft (136), the radially outer end (142b) of the second shaft (142), and the first end (144a) of the third shaft (144) being coupled together by bevel gears (146, 148, 150), and in that a second equipment (140) or second set of equipment is located radially inside the casing (28) and coupled to the second end (144b) of the third shaft (144).

2. A turbomachine (110) according to claim 1, wherein the second equipment (152) or set of equipment is selected from an engine, a generator, a motor-generator, a starter and a gearbox.

3. A turbomachine (110) according to claim 1 or 2, wherein the radially inner end (136a) of the first shaft (136) is interposed between the radially outer end (142b) of the second shaft (142) and the first end (144a) of the third shaft (144), the radially inner end (136a) of the first shaft (136) carrying a bevel gear (146) which is meshed with bevel gears (148, 150) carried respectively by the radially outer end (142b) of the second shaft (142) and by the first end (144a) of the third shaft (144).

4. Turbomachine (110) according to the preceding claim, in which the radially inner end (136a) of the first shaft (136) is guided in rotation by bearings (164, 166) mounted directly on the radially outer end (142b) of the second shaft (142) and the first end (144a) of the third shaft (144).

5. A turbomachine (110) according to claim 1 or 2, wherein the radially outer end (142b) of the second shaft (142) is interposed between the radially inner end (136a) of the first shaft (136) and the first end (144a) of the third shaft (144), the radially outer end (142b) of the second shaft (142) carrying a bevel gear (148) which is meshed with bevel gears (146, 150) carried respectively by the radially inner end (136a) of the first shaft (136) and by the first end (144a) of the third shaft (144).

6. Turbomachine (110) according to the preceding claim, in which the radially external end (142b) of the second shaft (142) is guided in rotation by bearings (164, 166) mounted directly on the radially internal end (136a) of the first shaft (136) and the first end (144a) of the third shaft (144).

7. Turbomachine (110) according to one of the preceding claims, in which the first shaft (136) is inclined relative to the axis (A) by an angle α of between 10 and 80°, and / or the second shaft (142) is inclined relative to the axis (A) by an angle [3 of between 10 and 80°, and / or the third shaft (144) is inclined relative to the axis (A) by an angle y of less than 20° in absolute value and preferably less than 10°.

8. Turbomachine (110) according to one of the preceding claims, in which the bevel gears (146, 148, 150) are chosen from straight bevel gears, spiral bevel gears and hypoid bevel gears.

9. Turbomachine (110) according to one of the preceding claims, in which the first equipment (140) or set of equipment is an accessory or gear box which extends around a part of the casing (14).

10. Turbomachine (110) according to the preceding claim, in which the first equipment (140) or set of equipment is coupled to the radially external end (136b) of the first shaft (136) by an angle transmission device (160).

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