Turbine engine accessory relay box

Abstract

The present document relates to an accessory relay box (12) for an aircraft, comprising a casing (14), at least one gear train mounted in the casing (14), the gear train comprising a plurality of pinions (15) meshing with one another, at least one primary pinion (40) comprising a primary shaft (42) extending along a primary axis (X), characterised in that it comprises a transmission system (51) arranged at a first end (44a) of the primary shaft (42) and intended to transmit power to a piece of equipment (34), the power transmission system (51) comprising an internally toothed ring gear (54) and a toothed wheel (52) engaging with the internal toothing of the ring gear (54), the toothed transmission wheel (52) having as its axis of rotation at least one of the primary axis (X) and an axis (Y) parallel to the primary axis (X).

Description

Description Title: Turbomachine accessory relay box Technical field

[0001] The present disclosure relates to an accessory relay box for an aircraft turbomachine, such as for example an aircraft turbojet or turboprop, or an industrial machine. Prior art

[0002] Figure 1 represents a turbomachine 1 of the prior art comprising from upstream to downstream in the direction of circulation of the gases within the turbomachine 1, a fan 2, a low pressure compressor 3, a high pressure compressor 4, a combustion chamber 5, a high pressure turbine 6 and a low pressure turbine 7. The air entering the turbomachine 1 is divided into a primary air flow (arrow A) which circulates in a so-called primary air stream 8 inside the low and high pressure compressors 3, 4 towards the combustion chamber 5 then through the high and low pressure turbines 6, 7, and into a secondary air flow (arrow B) which circulates in a so-called secondary air stream 9 bypassing the compressors 3, 4, the combustion chamber 5 and the turbines 6, 7. The streams 8, 9 are crossed by structural arms 10 extending radially.A structural arm 10 houses a power transmission shaft 11 extending substantially radially and the radially inner end of which is driven in rotation by the shaft of the high-pressure compressor 4. The radially outer end of the power transmission shaft 11 drives in rotation one end of a power transfer shaft 19 to an accessory relay box 12 of the turbomachine 1. This box 12 is conventionally arranged in a nacelle 13 forming a peripheral enclosure of the turbomachine 1.

[0003] As illustrated in Figure 2, this accessory relay box 12, commonly called AGB for “Accessory Gear Box”, comprises a fixed casing 14 and a gear train comprising a succession of pinions 15 meshing with each other and whose diameters are adapted so that certain pinions 15 are integral with output shafts 17 each serving to drive at least one piece of equipment 16, at a given speed.

[0004] These equipments 16 may include various pumps for the production of hydraulic energy, fuel supply, lubrication, electric generators for the production of electric power, etc.

[0005] As shown in Figures 3A, 3B, 3C, the accessory box comprises a first side wall 18 and a second side wall 20 facing each other. Each equipment 16 is generally mounted against one of said side walls 18, 20 of the housing 14 and is driven by a shaft 17 passing through the housing 14 at an opening 22 of the housing 14 and coupled to one of the pinions 15 of the gear train. The accessory relay box 12 is thus organized in stages, each stage comprising a shaft 17 of a pinion 15.

[0006] The accessory relay box 12 comprises a width along a direction I, a length along a direction J, and a height along a direction K.

[0007] These 16 devices may require different rotation speeds of their own. Typically, some electrical generators can reach rotation speeds six times higher than accessories with the lowest rotation speeds. This discrepancy in rotation speed between devices requires the arrangement of devices requiring different rotation speeds on separate stages of the accessory relay box.

[0008] Figure 3A shows a first embodiment of the prior art in which a first stage 24 comprises a first toothed wheel 26 of diameter d1 and a first equipment 28. A second stage 30 comprises a toothed wheel 32 of diameter d2, such that d2 > d1, engaged with the first toothed wheel 26, said second stage 30 further comprises a second equipment 34. In operation, the first toothed wheel 26 rotates the first equipment 28 having a rotation speed w1. The first toothed wheel 26 rotates the second toothed wheel 32 engaged with the first toothed wheel 26, and the second toothed wheel 32 rotates the second equipment 34 having a rotation speed œ2, such that OJ2 < OJ1. The presence of the second stage 30 at which the second large diameter toothed wheel 32 is mounted requires increasing the length and height of the casing 14 to be able to accommodate the second toothed wheel 32.

[0009] Figure 3B shows a second embodiment of the prior art in which a first stage 24 comprises a first gear wheel 26 of diameter d1, an additional transmission gear wheel 36 of diameter d1' such that d1' < d1 and a first equipment 28. A second stage 30 comprises a second gear wheel 32 of diameter d2, such that d2 > d1 > d1', meshing with the additional gear wheel 36, said second stage 30 further comprises a second equipment 34. In operation, the first gear wheel 26 rotates the first equipment 28 having a rotation speed w1. The additional transmission gear wheel 36 rotates the second gear wheel 32, and the second gear wheel 32 in turn rotates the second equipment 34 having a rotation speed œ2, such that OJ2 < OJ1.The presence of the second stage 30 at which the second toothed wheel 32 and the additional toothed wheel 36 are mounted requires increasing the length and width of the casing 14 respectively.

[0010] Figure 3C shows a third embodiment of the prior art in which the casing 14 has at its end an offset portion 38. A first stage 24 has a first toothed wheel 26 of diameter d1, an additional transmission toothed wheel 36 of diameter d1' such that d1' < d1, said additional transmission toothed wheel 36 being arranged in the offset portion 38 of the casing 14, and a first piece of equipment 28. A second stage 30 arranged in the offset portion 38 of the casing 14 comprises a second toothed wheel 32 of diameter d2, such that d2 > d1 > d1', meshing with the additional transmission toothed wheel 36, said second stage 30 further comprises a second piece of equipment 34. In operation, the first toothed wheel 26 drives the first piece of equipment 28 into rotation having a rotation speed w1.The additional transmission gear wheel 36 rotates the second gear wheel 32, and the second gear wheel 32 in turn rotates the second equipment 34 having a rotation speed œ2, such that OJ2 < OJ1. The presence of the second stage 30 at which the second gear wheel 32 and the offset portion 38 of the casing 14 are mounted requires increasing the length and width of the casing 14 respectively.

[0011] Some turbomachine architectures require the accessory relay box 12 to be positioned around the high-pressure compressor 4 where the available space is limited. It can therefore be complicated to add equipment due to the sizing issues mentioned previously in relation to Figures 3A, 3B and 3C. Therefore, the compactness of an accessory relay box is an essential characteristic for its integration into a turbomachine.

[0012] In document FR 3 008 462, it was proposed that one of the pinions forms an external crown of a device with an epicyclic configuration. While this configuration makes it possible to achieve power output at a speed different from that of the crown, it is nevertheless difficult to mount in the housing of the accessory relay box.

[0013] A compact accessory relay box is offered, allowing the mounting of accessories of different rotation speeds. Summary

[0014] For this purpose, the present disclosure relates to an aircraft accessory relay box comprising: - a casing having a first wall and a second wall facing the first wall; - at least one gear train mounted in the housing, the gear train comprising a plurality of pinions of parallel axes meshing with each other; - at least one primary pinion of said plurality of pinions comprising a primary shaft extending transversely between the first and second walls of the casing along a primary axis; characterized in that it comprises a transmission system arranged at a first end of the primary shaft and intended to transmit power to equipment, said first end of the primary shaft being oriented towards the first wall of the casing, said power transmission system being located at least partially in a recess in the first wall of the casing, the recess extending towards the second wall, said power transmission system comprising: -- an internally toothed crown; and -- a power transmission toothed wheel meshing with the internal teeth of the crown wheel, said toothed wheel having as its axis of rotation at least one of the primary axis and an axis parallel to the primary axis.

[0015] The terms axial and radial are defined relative to the primary axis.

[0016] According to the present document, the power transmission system is located at least partially in a recess of the housing. More particularly, the power transmission system is located outside the housing. A first equipment can be rotatably coupled to the primary shaft at the first end of the primary shaft via the power transmission system and can thus rotate at a different speed than the primary shaft, and a second equipment can be rotatably coupled to the primary shaft at a second end of the primary shaft opposite the first end and can thus rotate at the same speed as the primary shaft. Thus, the proposed configuration makes it possible to place two equipment having different rotational speeds opposite each other on the first and second walls of the housing, and at a single stage of the accessory relay box.

[0017] Compared to the embodiment of Figure 3A, the invention therefore makes it possible to reduce the length (along direction J) and the height (along direction K) of the casing.

[0018] Compared to the embodiment of Figure 3B, the invention therefore makes it possible to reduce the width (along direction I) of the casing.

[0019] Compared to the embodiment of Figure 3C, the invention therefore makes it possible to reduce the length (along direction J) and the width (along direction I) of the casing.

[0020] Furthermore, the embodiments of Figures 3A, 3B and 3C have meshing between the external teeth of the first and second stage gears. Compared to the embodiments of Figures 3A, 3B and 3C, the invention therefore makes it possible to reduce the length of the casing because the power transmission gear is meshed with the internal teeth of the crown.

[0021] This results in a more compact design depending on the length, width and / or height, reducing the size and making it easier to integrate the box into a turbomachine.

[0022] The accessory relay housing may further comprise a first and a second primary rolling bearing located on either side of the primary pinion and mounted around the primary shaft, said first primary rolling bearing being located axially between the first wall of the housing and the primary pinion, said second primary rolling bearing being located axially between the second wall of the housing and the primary pinion.

[0023] The first and second rolling bearings allow the primary gear to rotate in the accessory housing.

[0024] The first end of the primary shaft may comprise splines, and the transmission gear wheel may comprise a central opening, said central opening comprising splines capable of slidingly cooperating along the primary axis with the splines of the primary shaft so as to ensure rotational connection of the two parts.

[0025] The accessory relay housing may further include a secondary rolling bearing mounted around the ring gear.

[0026] The arrangement of the secondary rolling bearing around the crown wheel allows the radial power transmission forces from the power transmission gear wheel to the crown wheel to be taken up due to the misalignment of the axis of the crown wheel forming the output of the transmission system and the power input axis, i.e. the axis of the power transmission gear wheel.

[0027] Roller bearings can be used to effectively absorb radial forces. Ball bearings are also possible.

[0028] The crown may comprise at an inner end around which the secondary rolling bearing is mounted a radially external shoulder, an inner ring of the secondary rolling bearing being arranged in axial abutment against said radially external shoulder. In this way, the inner ring of the secondary rolling bearing is axially locked on a first side.

[0029] The accessory relay housing may further include an external nut mounted around the ring gear and axially bearing against an internal ring of the secondary rolling bearing.

[0030] The power transmission system can be partially or fully integrated into the equipment.

[0031] The inner ring of the rolling bearing used to absorb radial forces can thus be held axially between the shoulder of the crown on the first side and by the outer nut on a second opposite side.

[0032] An axial stop of an outer ring of the secondary rolling bearing may be provided, said axial stop being able to comprise an annular part bearing axially against the outer ring of the secondary rolling bearing and a cylindrical part located at a radially inner end of the annular part, said cylindrical part extending towards the bearings and being arranged between a cage and the outer ring of the secondary rolling bearing. Thus, the axial stop may have a generally L-shaped radial section. In this way, the outer ring of the secondary rolling bearing and the bearings are blocked at the second side.

[0033] The cylindrical part can be arranged between the cage and the inner ring of the secondary rolling bearing. In this way the inner ring of the rolling bearing and the bearings are locked at the second side.

[0034] The primary shaft may comprise at its first end a cylindrical bearing surface on which the transmission gear wheel is mounted, which is axially locked at a first end by a shoulder of said cylindrical bearing surface and at a second opposite end by an internal nut screwed onto an internal surface of the cylindrical bearing surface.

[0035] This assembly allows the transmission gear wheel to be held axially between the internal nut and the shoulder of the primary shaft.

[0036] The internal nut may further comprise an annular portion in axial contact with the first end of the primary shaft and a cylindrical portion located at a radially internal end of the annular portion of the internal nut, said cylindrical portion extending axially towards the inside of the casing and comprising a radially external surface, said radially external surface comprising a thread capable of cooperating with the internal wall of the cylindrical bearing surface. Thus, the internal nut may have a generally L-shaped radial section.

[0037] The inner nut can be screwed onto an outer wall of the cylindrical bearing surface and arranged in axial abutment against the transmission gear wheel. In this way, the assembly allows the transmission gear wheel to be held axially between the inner nut and the shoulder of the input shaft.

[0038] The crown may comprise a first cylindrical part carrying the internal teeth and a second cylindrical part connected to a disc comprising a central passage in which at least one lubricating oil nozzle is mounted.

[0039] The central passage may include teeth on a radially inner surface engaging teeth on a radially outer surface of the lubricating oil nozzle.

[0040] The central passage of the disc allows lubricating oil to be supplied to the inside of the crown, the oil can then circulate to the mesh between the internal teeth of the crown and the teeth of the transmission gear. This oil can also circulate to the secondary rolling bearing.

[0041] The inner nut may include at least one oil circulation hole formed through the cylindrical portion of the inner nut and extending from a radially inner surface of the cylindrical portion of the inner nut to a radially outer surface of the cylindrical portion of the inner nut. In this manner, the circulation hole allows oil to circulate at the meshing between the internal teeth of the transmission gear and the splines of the first end of the input shaft.

[0042] The accessory relay housing may further comprise at least one radial orifice formed through the crown for the circulation of oil to the secondary rolling bearing and an annular oil recovery scoop arranged radially opposite said radial orifice. In a particular case, the housing may comprise one or a plurality of radial orifices.

[0043] A first level ring may be provided comprising an annular portion in axial contact with the cylindrical surface of the central passage, and a cylindrical portion extending axially from a radially outer end of the annular portion. The cylindrical portion may be mounted around the central passage of the crown disc and the first level ring may have a generally L-shaped radial section. In this way, centrifuged oil may be concentrated at the meshing between the teeth of the radially inner surface of the central passage and the teeth of the radially outer surface of the nozzle.

[0044] According to another feature, the accessory relay housing may include a second and a third level ring housed in two radial grooves of the crown wheel, these grooves opening radially inwards and being located on either side of the teeth of the crown wheel. In this way, centrifuged oil can be concentrated at the meshing between the internal teeth of the crown wheel and the teeth of the transmission gear wheel.

[0045] The transmission system may comprise an epicyclic gear train comprising: - a primary axis sun gear; - a plurality of planetary pinions, one of which is formed by the transmission toothed wheel, said planetary pinions being engaged with the crown wheel and with the sun pinion; - a planet carrier on which said planet gears are mounted to rotate freely, in which at least a first element among the sun gear, the planet carrier and the crown is connected to the first end of the primary shaft, a second element among the planet carrier and the crown is secured to the casing and a third element among the sun gear, the planet carrier and the crown is intended to be connected to equipment.

[0046] In this assembly, power transmission is achieved through an epicyclic gear train. This provides good axisymmetric balancing of the radial load transmitted by the primary shaft to an output shaft secured to the third element. Furthermore, power transmission through an epicyclic gear train provides additional compactness compared to the previous assembly. In operation, power transmission is from the primary pinion to the primary shaft, then to the first element, the second element, the third element, and finally to the equipment.

[0047] The accessory relay housing may include a tertiary rolling bearing rotatably guiding at least the third element.

[0048] The epicyclic gear train may comprise planetary rolling bearings arranged radially between the planetary pinions and cylindrical protruding portions of the planet carrier on which the planetary pinions are mounted so as to rotate freely. In this way, the planetary rolling bearings guide the cylindrical protruding portions of the planet carrier and the planetary pinions in rotation.

[0049] The tertiary rolling bearing can guide the first element in rotation.

[0050] The tertiary rolling bearing may comprise an outer ring secured to the housing and an inner ring secured to the third element. In other words, the tertiary rolling bearing may be arranged radially outside the crown wheel so that the outer ring is carried by the housing and the inner ring is rotationally secured to the crown wheel.

[0051] The first member may include an end inserted and rotatably coupled into the first end of the primary shaft.

[0052] The first element may comprise splines engaging with a toothing of the inner wall of the first end of the primary shaft. In this way, the first element is mechanically connected to the primary shaft.

[0053] The first end of the primary shaft may be integral with the end of the first element.

[0054] The first primary rolling bearing may be arranged radially at least partly around said end of the first element.

[0055] The arrangement of the primary rolling bearing around the end of the first element makes it possible to effectively absorb radial forces and to ensure guidance of the first element by limiting its overhang on the first end of the primary shaft.

[0056] The tertiary rolling bearing can be arranged in a radial plane passing through the planet gears, the crown wheel and the sun gear. Such an arrangement of the tertiary rolling bearing allows the radial forces to be effectively absorbed in the radial plane.

[0057] The tertiary rolling bearing can be arranged radially inside the planet gears and thus ensures guidance of the first element with the third element.

[0058] The first and second primary rolling bearings, the secondary rolling bearings and the tertiary rolling bearings may be double row angular contact ball bearings or hydrodynamic bearings.

[0059] The present disclosure also relates to a turbomachine comprising an accessory relay box according to the aforementioned type.

[0060] Said turbomachine may be an aircraft turbojet or turboprop.

[0061] Said turbomachine may be a hybrid propulsion assembly comprising an electric machine and a thermal engine. Said sealing assembly may be located at the interfaces between a power transmission and the thermal engine, on the one hand, or the electric machine, on the other hand.

[0062] This document also relates to an aircraft comprising at least one turbomachine of the aforementioned type.

[0063] Said aircraft may be an airplane or a rotary-wing aircraft such as, for example, a helicopter. Brief description of the drawings

[0064] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: [Fig. 1] is a schematic longitudinal sectional view of a prior art turbomachine, [Fig. 2] is a schematic perspective view of a prior art accessory relay housing, [Fig. 3A] is a schematic longitudinal sectional view of a prior art accessory relay housing according to a first embodiment, [Fig. 3B] is a schematic longitudinal sectional view of a prior art accessory relay housing according to a second embodiment, [Fig. 3C] is a schematic longitudinal sectional view of a prior art accessory relay housing according to a third embodiment, [Fig. 4] is an axial sectional view of the accessory relay housing according to a first embodiment of the present document, [Fig. 5A] is an axial sectional and perspective view of a portion of the accessory relay housing of Figure 4, [Fig. 5B] is an axial sectional view of the accessory relay housing of Fig. 5A, [Fig. 6A] is a perspective view of the accessory relay housing according to a second embodiment of the present document comprising an epicyclic configuration power transmission system, [Fig. 6B] is a view of the accessory relay housing of Fig. 6A along the axis of a sun gear of the epicyclic gear train and from outside the accessory relay housing casing, [Fig. 6C] is an axial sectional view of the accessory relay housing of Fig. 6A along a sectional plane VI C of Fig. 6B including the axis of rotation of a primary pinion forming an input to the epicyclic gear train, [Fig. 7A] is a perspective view of the accessory relay housing according to a third embodiment of the present document comprising an epicyclic configuration power transmission system, [Fig. 7B] is a view of the accessory relay housing of Fig. 7A along the axis of a sun gear of the epicyclic gear train and from outside the accessory relay housing casing, [Fig. 7C] is an axial sectional view of the accessory relay housing of Fig. 7A along a section plane VII C of Fig. 7B including the axis of rotation of a primary pinion forming an input of the epicyclic gear train, [Fig. 8A] is a perspective view of the accessory relay housing according to a fourth embodiment of the present document comprising an epicyclic configuration power transmission system, [Fig. 8B] is a view of the accessory relay housing of Fig. 8A along the axis of a sun gear of the epicyclic gear train and from outside the accessory relay housing casing, [Fig. 8C] is an axial sectional view of the accessory relay housing of Fig. 8A along a sectional plane VIII C of Fig. 8B including the axis of rotation of a primary pinion forming an input to the epicyclic gear train, [Fig. 9A] is a perspective view of the accessory relay housing according to a fifth embodiment of the present document comprising an epicyclic configuration power transmission system, [Fig. 9B] is a view of the accessory relay housing of Fig. 9A along the axis of a sun gear of the epicyclic gear train and from outside the accessory relay housing casing, and [Fig. 9C] is an axial sectional view of the accessory relay housing of Fig. 9A along a sectional plane IX C of Fig. 9B including the axis of rotation of a primary pinion forming an input to the epicyclic gear train. Description of the embodiments

[0065] Figures 4, 5A and 5B illustrate an accessory relay box according to a first embodiment of the present document.

[0066] The accessory relay housing 12 extends along a longitudinal axis L and comprises a casing 14 having a first wall 18 and a second wall 20 arranged opposite the first wall 18. A gear train is mounted inside the casing 14, between the first wall 18 and the second wall 20 and comprises a plurality of pinions 15 meshing with each other, each pinion 15 being connected to a shaft 17. The axes of the shafts 17, i.e. the axes of the pinions 15 are parallel to each other.

[0067] A plurality of equipment 16 is arranged axially against one of the first wall 18 or the second wall 20 of the housing 14. Each equipment is rotatably connected to a shaft 17 of the gear train.

[0068] As illustrated in Figure 4, a longitudinal end of the gear train comprises a primary pinion 40 crossed in its center by a primary shaft 42 extending between the first 18 and the second wall 20 of the casing 14. The primary pinion and the rotation shaft are capable of rotating along an axis of rotation called primary axis X, which comprises a first direction oriented X1 towards the first wall 18 and a second direction X2 oriented towards the second wall 20.

[0069] As illustrated in Figures 5A and 5B, the primary shaft 42 comprises a first portion 44 oriented from the primary pinion 40 towards the first wall 18 of the casing 14 (direction X1) and has a first end 44a. The primary shaft 42 comprises a second portion 46 which is oriented from the primary pinion 40 towards the second wall 20 of the casing 14 (direction X2) and which has a second end 46a.

[0070] As illustrated in Figure 1, a power transfer shaft 19 forms a power input for the gear train.

[0071] In operation, the power transfer shaft 19 provides input power to the gear train, thereby rotatingly engaging the pinions 15 and their connecting shafts 17 and then the plurality of equipment 16 rotatably coupled to the plurality of connecting shafts 17.

[0072] Reference is now made to Figures 4, 5A and 5B which illustrate on a larger scale the connection of the primary shaft 42 to the power transmission system according to the present document and according to a first embodiment. According to the present document, said power transmission system is located at least partially in a recess 21 of the first wall 18 of the casing 14, the recess 21 extending towards the second wall 20.

[0073] The first part 44 of the primary shaft 42 comprises a frustoconical wall 44b with a section increasing towards the first wall 18 and extending towards the first wall 18 by a cylindrical bearing surface 44c. The cylindrical bearing surface 44c externally comprises a first cylindrical surface 44f-1 extending by a radial shoulder 44d then by a second cylindrical surface 44f-2 which comprises grooves. The radially internal surface of the cylindrical bearing surface 44c comprises a tapped portion 44g opening at the first end 44a of the primary shaft 44.

[0074] First 48 and second 50 primary rolling bearings are mounted on either side of the primary pinion 40 and around the first cylindrical bearing surface 44c of the first portion of the primary shaft 42 and the second portion of the primary shaft 42 respectively. More particularly, the primary bearing 48 is mounted around the first cylindrical surface 44f-1 and is engaged in abutment in the second direction X2 against an annular rim 49 of the second portion 46 of the primary shaft 44. Said first 48 and second 50 primary rolling bearings comprise radially inner rings 48a, 50a in radial contact with the first cylindrical bearing surface 44c of the first portion 44 of the primary shaft 42 and the second portion 46 of the primary shaft 42, respectively. The first 48 and second 50 primary bearings also comprise an outer ring 48b, 50b.

[0075] A power transmission system 51 is arranged at the first end 44a of the first portion 44 of the primary shaft 42 so as to transmit the rotational torque of the primary pinion to the shaft.

[0076] The transmission system comprises a transmission toothed wheel 52 which is arranged around the cylindrical bearing surface and more precisely on the second surface 44f-2 of the cylindrical bearing surface and in the second direction X2. The radially internal surface of the toothed wheel 52 comprises splines cooperating in sliding manner along the primary axis with the splines of the second surface 44f-2. The transmission system also comprises a crown wheel 54 having an axis of rotation Y parallel to the primary axis X. The crown wheel 54 comprises a first cylindrical portion 56 surrounding the toothed wheel 52, said first cylindrical portion 56 comprising an internal annular toothing 56a engaged with an external toothing 52b of the toothed wheel 52. The first cylindrical portion of the crown wheel 54 comprises a radial annular rim 56b which extends radially outwards from an end 56c of the first cylindrical portion 56 oriented in the second direction X2.

[0077] The crown 54 further comprises a second cylindrical part 58 located at a second end 56d of the first cylindrical part 56 and oriented in the first direction X1. The end of the second cylindrical part 58 opposite the first cylindrical part 56 is connected to a disc 60 comprising a central passage 62 in the form of an axially projecting tubular part 62 extending on either side of the disc 60. The axially projecting tubular part 62, along the axis Y of the crown 54, comprises a toothing located on an internal cylindrical wall 62a.

[0078] An internal nut 64 is screwed onto the threaded portion 44g of the internal surface of the cylindrical bearing surface 44c. This internal nut 64 comprises a cylindrical portion 64a arranged radially inside said internal surface of the cylindrical bearing surface 44c. The internal nut 64 may also comprise a radial annular portion 64b extending radially outwards from one end of the cylindrical portion 64a oriented in the second direction X2, the annular portion 64b being in axial contact with the first end 44a of the primary shaft 44 and ensures axial locking of the toothed wheel 52 in the first direction X1, the locking of the toothed wheel 52 in the second direction being carried out on the shoulder 44d.

[0079] A secondary rolling bearing 66 may be arranged around the first cylindrical part 56 of the crown 54. It may thus comprise a radially inner ring 66a in radial contact with the first cylindrical part 56 of the crown 54 and in axial abutment against the annular rim 56b of the first cylindrical part 56 of the crown 54. A radially outer ring 66b and bearings 66c, for example of the roller type, are mounted radially between the inner ring 66a and the outer ring 66b and cooperate with a cage 66d of said secondary rolling bearing 66.

[0080] The outer ring 66b comprises a base 66e, said base 66e comprising a first end 66f oriented in the second direction X2 and a second end 66g oriented in the first direction X1. The outer ring 66b may further comprise a first branch 66h extending radially inward from the first end 66f of the base 66e and a second branch 66i extending radially outward from the second end 66g of the base 66e, such that the outer ring 66b has a generally Z-shaped radial section.

[0081] An external nut 68 is mounted around the second cylindrical part of the crown 54 and so as to come into axial contact with the internal ring 66a of the secondary rolling bearing 66.

[0082] Thus, the inner ring 66a of the secondary rolling bearing 66 is held axially between the annular rim 56b of the first cylindrical part 56 of the crown 54 and the outer nut 68.

[0083] An axial stop member 70 is applied against the outer ring 66b of the secondary rolling bearing 66 and in the second direction X2. This stop member 70 comprises an annular part 70a in radial contact with the second branch 66i of the outer ring 66b and a cylindrical part 70b extending from a radially internal end 70c of the annular part 70a and in the second direction X2, the cylindrical part 70b being located partly radially between the cage 66d and the base 66e of the outer ring 66b of the secondary rolling bearing 66.

[0084] The axial stop member 70 thus makes it possible to axially block the outer ring 66b in the first direction X1. The cylindrical part 70b makes it possible to axially block the bearings of the secondary bearing 66 in the first direction.

[0085] The transmission system is intended to receive a shaft 72 of equipment 34. This shaft is engaged in the axially projecting tubular part 62 of the crown 58 and comprises an external toothing 72a engaged with the internal toothing of the tubular part of the disc 60 of the crown 58.

[0086] In operation, the plurality of pinions 15 of the gear train rotates the primary pinion 40, then the primary shaft 42, the transmission toothed wheel 52 then the crown 54 and finally the equipment 34. It is observed that the external diameter of the toothed wheel is less than the internal diameter of the crown so that the transmission system allows a speed reduction between the speed OJ1 of the primary shaft 44 and the speed OJ2 of the shaft 72 of the equipment in a reduced size, unlike the prior art as described with reference to figures 3A, 3B and 3C.

[0087] A lubricating oil nozzle 76 may be formed in the shaft 72 of the equipment 34 and may comprise at least one orifice, two in particular, for spraying 76a, 76b whose axis is oriented obliquely relative to the axis of rotation Y of the crown 54 and towards the inside of the casing 14.

[0088] In operation, lubricating oil is ejected through the orifices 76a, 76b of the nozzle 76 and flows to the teeth of the toothed wheel 52 and the crown wheel 54.

[0089] A radial orifice 78 delimiting the first 56 and the second 58 cylindrical part of the crown 54 extends from a radially internal cylindrical surface 56e of the crown 54 to a radially external surface 68a of the external nut 68.

[0090] An annular scoop 80 is arranged partly in axial contact with the axial stop member 70 and may comprise an axial step 80a oriented in the first direction X1 and connected to a radial annular wall 80b extending radially inwards.

[0091] In operation, the lubricating oil flows through the radial orifice 78 and is redirected to the roller 66e of the secondary rolling bearing 66 by the annular scoop 80.

[0092] Two level rings 82, 84 are located at the level of the first cylindrical part 56 of the crown 54 and are housed in two radial orifices 56f, 56g arranged on either side of the internal toothing 56a of the crown 54.

[0093] In operation, the centrifuged oil is concentrated in two annular spaces delimited by the internal teeth 56a of the crown 54 and the two level rings 82, 84. In this way, the lubrication of the meshing between the internal teeth 56a of the crown 54 and the external teeth 52b of the transmission toothed wheel 52 is improved.

[0094] Two radial orifices 86, 88 are located at the level of the cylindrical part 64a of the internal nut 64 and extend from a radially internal surface 64c to a radially external surface 64d of the cylindrical part 64a of the internal nut 64 opening opposite the cylindrical bearing surface 44c of the primary shaft 42.

[0095] In operation, the oil circulates through the radial orifices 86, 88 of the internal nut 64. In this way, the lubrication of the meshing between the splines of the cylindrical bearing surface 44c and an internal toothing 52a of the transmission toothed wheel 52 is improved.

[0096] Figures 6A, 6B, 6C, 7A, 7B, 7C, 8A, 8B, 8C, 9A, 9B and 9C illustrate embodiments comprising a transmission system comprising a gear train with an epicyclic configuration.

[0097] In the configurations illustrated in Figures 6A, 6B, 6C, 7A, 7B, 7C, 8A, 8B, 8C, 9A, 9B and 9C, the epicyclic gear train comprises: - a 90 sun gear with primary axis X; - a plurality of satellite pinions 94, one of which forms the transmission toothed wheel 52, said satellite pinions 94 being engaged with the crown 54 and with the sun pinion 90; - a planet carrier 96 on which said planet gears 94 are mounted to rotate freely.

[0098] According to these embodiments, at least a first element among the sun gear 90, the planet carrier 96 and the crown 54 is connected to the first end 44a of the primary shaft 42, a second element among the planet carrier 96 and the crown 54 is secured to the casing 14 and a third element among the sun gear 90, the planet carrier 96 and the crown 54 is intended to be connected to an item of equipment 34.

[0099] Figures 6A, 6B and 6C illustrate an accessory relay housing according to a second embodiment of the present document.

[0100] The second embodiment has a similar architecture to the first embodiment and differs therefrom in that: - the transmission system 51 is a gear train with epicyclic configuration, - the first part 44 of the primary shaft 42 only carries the first primary rolling bearing 48 and therefore does not carry the power transmission toothed wheel since the latter is integrated into the epicyclic gear train.

[0101] The first wall 18 of the casing 14 also comprises a recess 21 which is oriented towards the second wall 20 of the casing 14. The recess 21 is delimited by a first radial annular wall 21a, one radially external end of which is connected to a first cylindrical wall 21b, one end of which oriented in the first direction X1 is connected to a longitudinal part of the wall 14. The radially internal end of the first radial annular wall 21a surrounds the external ring 48b of the first primary bearing 48. In this way, the periphery of the radially internal end of the first radial annular wall 21a ensures centering of the external ring 48b of the first primary bearing 48 and the internal ring ensures the rotational guidance of the primary shaft 44.

[0102] The second wall 20 of the casing 14 comprises an opening 20a in which the outer ring 50b of the second primary rolling bearing 50 is mounted.

[0103] The crown 54 is arranged at the first end 44a of the primary shaft 44 and is housed in the recess 11 of the first wall 18 of the casing 14.

[0104] This crown 54 comprises a disc 54a arranged axially along the primary axis X between the first radial annular wall 21a and the planet gears 94. The disc 54a is connected at its radially outer end to an outer cylindrical wall 54b carrying an internal toothing engaged with the planet gears 94. The radially inner end of the disc 54a comprises a central portion 54c extending along the primary axis X and which may comprise a central orifice 55 as illustrated in FIG. 6C. A cylindrical wall 54d extends along the second direction X2 from the disc 54a and is arranged radially between the central portion 54c and the outer cylindrical wall 54b.

[0105] The cylindrical wall 54d of the crown 54 is integral with the cylindrical bearing surface 44c of the primary shaft 42. In this way, the crown 54 forms the power input of the power transmission system.

[0106] A sun gear 90 is arranged around the central portion 54c of the crown 54 and comprises a first cylindrical bearing surface 90a comprising external teeth, followed by a radially internal shoulder 90b and a second cylindrical bearing surface 90c intended to form the output of the transmission system 51. This second cylindrical bearing surface 90c of the sun gear is intended to be connected to equipment 34.

[0107] A tertiary rolling bearing 92 is mounted radially between the central portion 54c of the crown 54 and the first cylindrical bearing surface 90a of the sun gear 90. This tertiary bearing 92 comprises an inner ring 92a in radial contact with the central portion 54c of the crown 54 and an outer ring 92b in radial contact with the first cylindrical bearing surface 90a of the sun gear 90. The inner ring 92a and the outer ring 92b of the tertiary rolling bearing 92 are in axial abutment against the shoulder 90b of the sun gear 90.

[0108] At least two planet gears 94, in the example shown three planet gears 94, are arranged radially between the external cylindrical wall 54b of the crown 54 and the sun gear 90 and comprise an external toothing 94a in engagement with the internal toothing of the external cylindrical wall 54b of the crown 54 and the external toothing of the first cylindrical bearing surface 90a of the sun gear 90.

[0109] A planet carrier 96 comprises a ring 96a arranged outside the recess 21 of the first wall 18 of the casing 14 and connected to an openwork disc 96b which is formed in a single piece with the ring 96a. The ring 96a is connected to the openwork disc 96b by means of several branches 96d, here three branches, delimiting with the ring and the disc three openwork zones 96c. The branches can extend substantially radially. The perforated disc 96b comprises a central opening 96b allowing the passage of the second cylindrical bearing 90c of the sun gear 90. An axial rod 96f extends from each branch in the second direction X2 and is engaged in a satellite gear 94. The ring 96 of the planet carrier comprises ears 97 each comprising an orifice for the passage of a fixing screw to the first wall 18.

[0110] A planetary bearing 98 is mounted around each rod 96f and in a central opening 94b of a planetary pinion 94. Each bearing includes an inner ring 98a and an outer ring 98b.

[0111] In operation, the power transmission is carried out from the primary pinion 40 to the primary shaft 42, then to the crown 54, to the satellite pinions 94, and finally to the sun pinion 90. Thus, the crown 54 and the sun pinion 90 respectively form the input and output of the power transmission system 51 which is a multiplier epicyclic gear train.

[0112] A radial plane P perpendicular to the X axis passes through the planet gears 94, the planet carrier 96 and the sun gear 90.

[0113] Figures 7A, 7B and 7C illustrate an accessory relay box 12 according to a third embodiment of the present document.

[0114] The third embodiment has a similar architecture to the second embodiment and differs in that: - the crown 54 is arranged in the radial plane P, - the ring 96a and the perforated disc 96b of the planet carrier 96 are located axially between the sun gear 90 and the cylindrical bearing surface 44c of the primary shaft 42, and - the planet carrier 96 has a shape different from that illustrated in Figures 6A, 6B and 6C. This planet carrier 96 thus comprises a central portion 96g projecting axially and which is mounted radially inside and in radial contact with the inner ring 92a of the tertiary rolling bearing 92. The planet carrier also has a cylindrical wall 96h oriented in the second direction X2 and engaged inside the cylindrical bearing surface 44c of the first part 44 of the primary shaft 4. Thus, the planet carrier forms the power input of the power transmission system.

[0115] It is observed that the external crown comprises ears 97 each comprising an orifice for the passage of a fixing screw to the first wall 18.

[0116] In operation, the power transmission is carried out from the primary pinion 40 to the primary shaft 42, then to the planet carrier 96, to the planet gears 94, and finally to the sun gear 90. Thus, the planet carrier 96 and the sun gear 90 respectively form the input and output of the power transmission system 51 which is a multiplier epicyclic gear train.

[0117] Figures 8A, 8B and 8C illustrate an accessory relay box 12 according to a fourth embodiment of the present document.

[0118] The fourth embodiment has a similar architecture to the third embodiment and differs in that: - the sun gear 90 comprises an additional axially projecting cylindrical part 90d oriented towards the inside of the casing 14, located radially inside the cylindrical bearing surface 44c of the first part 44 of the primary shaft 42 and an annular part 90e extending radially towards the outside and comprising at one end 90f a toothing engaged with an internal toothing of the cylindrical bearing surface 44c of the first part 44 of the primary shaft 42, - the recess 21 is delimited by the first radial annular wall 21a connected at its radially external end to the first cylindrical wall 21b which is itself connected externally to a second radial annular wall 21c which is connected to a second cylindrical wall 21d, - the ring 96a of the planet carrier 96 is mounted and made integral with the first cylindrical part 21b of the recess 21, - the crown 54 comprises a disc 60 located outside the recess 21 of the first wall 18 of the casing 14, a central tubular projecting portion 62 oriented towards the outside of the casing 14, that is to say say following the first direction X1 and intended to be coupled, by grooves for example to equipment 34, and - the tertiary rolling bearing 92 is located radially between the second cylindrical part 21d of the recess 21 and the crown 54, the inner ring 92a of the tertiary rolling bearing 92 being in radial contact with the crown 54 and the outer ring 92b of the tertiary rolling bearing 92 being in radial contact with the shoulder 18c of the first wall 18 of the casing 14.

[0119] In operation, the power transmission is carried out from the primary pinion 40 to the primary shaft 42, then to the sun pinion 90, to the satellite pinions 94, and finally to the crown 54. Thus, the sun pinion 96 and the crown 54 respectively form the input and output of the power transmission system 51 which is a reduction epicyclic gear train.

[0120] Figures 9A, 9B and 9C illustrate an accessory relay box 12 according to a fifth embodiment of the present document.

[0121] The fifth embodiment has a similar architecture to the fourth embodiment and differs in that: - the tertiary rolling bearing 92 is radially located inside the sun gear 90, the radially inner ring 92a of the tertiary rolling bearing 92 being in radial contact with the sun gear 90, - the perforated disc 96b of the planet carrier 96 is located outside the recess 21 of the first wall 18 of the casing 14, the planet carrier 96 comprises a first additional axially projecting part 96g oriented towards the inside of the casing 14 and in radial contact with the internal ring 92a of the tertiary rolling bearing 92 and a second additional axially projecting part 96h oriented towards the outside of the casing 14 intended to be in connection with the equipment 34, and - the crown 54 is integral with the first cylindrical wall 21 b of the recess 21.

[0122] In operation, the power transmission is carried out from the primary pinion 40 to the primary shaft 42, then to the sun pinion 90, to the satellite pinions 94, and finally to the planet carrier 96. Thus, the sun pinion 90 and the planet carrier 96 respectively form the input and output of the power transmission system 51 which is a reduction epicyclic gear train.

Claims

Claims

1. Accessory relay housing (12) for aircraft comprising: - a casing (14) having a first wall (18) and a second wall (20) opposite the first wall (18); - at least one gear train mounted in the housing (14), the gear train comprising a plurality of pinions (15) of parallel axes meshing with each other; - at least one primary pinion (40) of said plurality of pinions (15) comprising a primary shaft (42) extending transversely between the first (18) and the second wall (20) of the casing (14) along a primary axis (X); characterized in that it comprises a transmission system (51) arranged at a first end (44a) of the primary shaft (42) and intended to transmit power to an equipment (34), said first end (44a) of the primary shaft (42) being oriented towards the first wall (18) of the casing (14), said power transmission system (51) being located at least partially in a recess (21) of the first wall (18) of the casing (14), the recess (21) extending towards the second wall (20), said power transmission system (51) comprising: -- a crown (54) with internal teeth; and -- a power transmission gear wheel (52) meshing with the internal teeth of the crown wheel (54), said transmission gear wheel (52) having as its axis of rotation at least one of the primary axis (X) and an axis parallel (Y) to the primary axis (X).

2. An accessory relay housing (12) according to the preceding claim, further comprising a first (48) and a second primary rolling bearing (50) located on either side of the primary pinion (40) and mounted around the primary shaft (42), said first primary rolling bearing (48) being located axially between the first wall (18) of the housing (14) and the primary pinion (40), said second primary rolling bearing (50) being located axially between the second wall (20) of the housing (14) and the primary pinion (40).

3. An accessory relay housing (12) according to one of the preceding claims, wherein the power transmission system (51) further comprises a secondary rolling bearing (66) mounted around the ring gear (54).

4. Accessory relay housing (12) according to the preceding claim, wherein it further comprises an external nut (68) mounted around the crown (54) and axially bearing against an internal ring (66a) of the secondary rolling bearing (66).

5. Accessory relay housing (12) according to the preceding claim, wherein the primary shaft (42) comprises at its first end (44a) a cylindrical bearing surface (44c) on which is mounted the transmission toothed wheel (52) which is axially locked at a first end by a shoulder (44d) of said cylindrical bearing surface (44c) and at a second opposite end by an internal nut (64) screwed onto an internal surface of the cylindrical bearing surface (44c).

6. Accessory relay housing (12) according to one of the preceding claims, in which the crown (54) comprises a first cylindrical part (56) carrying the internal teeth and a second cylindrical part (58) connected to a disc (60) comprising a central passage (62) in which is mounted at least one nozzle (76) of lubricating oil.

7. Accessory relay housing (12) according to the preceding claim, further comprising at least one radial orifice (78) formed through the crown (54) for the circulation of oil to the secondary rolling bearing (66) and an annular scoop (80) for recovering oil arranged radially opposite said radial orifice (78).

8. An accessory relay housing (12) according to claim 1 or 2, wherein the transmission system (51) comprises an epicyclic gear train comprising: - a sun gear (90) with primary axis (X); - a plurality of planet gears (94), one of which is formed by the transmission gear wheel (52), said planet gears (94) being engaged with the crown wheel (54) and with the sun gear (90); - a planet carrier (96) on which said planet gears (90) are mounted to rotate freely, in which at least a first element among the sun gear (90), the planet carrier (96) and the crown (54) is connected to the first end (44a) of the primary shaft (42), a second element among the planet carrier (96) and the crown (54) is secured to the casing (14) and a third element among the sun gear (90), the planet carrier (96) and the crown (54) is intended to be connected to the equipment (34).

9. Accessory relay housing (12) according to the preceding claim, comprising a tertiary rolling bearing (92) guiding in rotation at least the third element.

10. An accessory relay housing (12) according to claim 9, wherein the tertiary rolling bearing (92) rotationally guides the first member.

11. An accessory relay housing (12) according to claim 9, wherein the tertiary rolling bearing (92) comprises an outer ring (92b) integral with the housing (14) and an inner ring (92a) integral with the third element.

12. An accessory relay housing (12) according to one of claims 8 to 11, wherein the first member comprises an end inserted and rotatably coupled into the first end (44a) of the primary shaft (42).

13. An accessory relay housing (12) according to claim 12, wherein the first primary rolling bearing (48) is arranged radially at least partially around said end of the first member.

14. An accessory relay housing (12) according to claim 13 wherein the tertiary rolling bearing (92) is arranged in a radial plane (P) passing through the planet gears (94), the ring gear (54) and the sun gear (90).

15. Turbomachine, such as an aircraft turbojet or turboprop, comprising an accessory relay box (12) according to one of the preceding claims.

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