MECHANICAL GEARBOX WITH PLANETARY ELEMENTS EQUIPPED WITH A LUBRICATION DEVICE

Abstract

The gearbox is provided with a centrifugal impeller (200) integral with a rotating planetary element of the gearbox, said impeller having an inlet portion (190) configured to receive lubricant and a distribution circuit for said lubricant from said inlet portion to the components to be lubricated of said gearbox, the circuit comprising at least one channel equipped with a strainer (23) for filtering said lubricant, a through hole (24) being made in a wall of said channel in the vicinity of said strainer and upstream of said strainer along the flow of said lubricant. Figure for the abbreviation: Fig 5

Description

Title of the invention: MECHANICAL REDUCER WITH PLANETARY ELEMENTS EQUIPPED OF A LUBRICATION DEVICE technical field

[0001] The invention relates, in general, to mechanical planetary gearboxes for aircraft turbomachinery and relates more particularly to a lubrication assembly for such a gearbox comprising a centrifugal wheel attached to a rotating planetary gear of the gearbox. Previous techniques

[0002] The role of a mechanical reducer is to modify the speed and torque ratio between the input shaft and the output shaft of a mechanical system.

[0003] With regard to aircraft turbomachinery, and in particular double-flow turbomachinery, especially those with a very high bypass ratio, the mechanical reducer has the role of driving the shaft of a fan by transforming the so-called high rotational speed of the shaft of a power turbine into a slower rotational speed for the shaft driving the fan.

[0004] Such a reducer includes a central pinion, called a solar pinion, which is driven by a drive shaft which receives the drive torque, a ring gear, which transmits the torque, at the output to the blower shaft, and pinions called satellite gears which are meshed between the solar pinion and the ring gear.

[0005] The satellites are held by a chassis called a satellite carrier. The solar array, the corona, and the satellite carrier are planetary because their axis of revolution coincides with the longitudinal axis X of the turbomachine.

[0006] The satellites have different axes of revolution distributed over the same operating diameter around the axis of the planetary gears

[0007] These axes are parallel to the longitudinal axis X.

[0008] There are several reducer architectures.

[0009] In the state of the art of double-flow turbomachinery, the reducers are of the planetary or epicyclic type.

[0010] In other similar applications, there are so-called differential architectures.

[0011] On a planetary reducer, the planet carrier is fixed and the ring constitutes the output shaft of the device which rotates in the opposite direction to the solar.

[0012] On an epicycloidal reducer, the ring is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the sun.

[0013] On a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the sun and the satellite carrier.

[0014] Reducers can be composed of one or more gearing stages.

[0015] This meshing is achieved, for example, by contact, by friction, or by magnetic fields. There are several types of contact meshing, for example, spur, helical, or herringbone gears.

[0016] The lubrication of the gears between the planetary gears and the satellite gears and / or the satellite bearings is classically ensured by a lubrication device comprising a centrifugal distributor, also called a wheel, fixed in rotation to a planetary gear of the reducer.

[0017] Such a wheel has an inlet portion configured to receive lubricant and a lubricant distribution circuit from the inlet portion to the parts to be lubricated of the reducer.

[0018] The device further includes means for securing the wheel to a rotating planetary element of the reducer, for example the planet carrier.

[0019] The rotation of the impeller, by centrifugal force, drives the lubricant, which is then distributed under pressure in the distribution circuit. The circuit is also equipped with nozzles that direct the lubricant to the components of the gearbox requiring lubrication.

[0020] The supply of lubricant to the wheel is ensured by a lubricant supply unit attached to a motor frame, the unit being thus fixed while the wheel is rotating.

[0021] The supply unit is therefore configured to transfer the lubricant to the impeller in the form of a jet directed towards the impeller's inlet portion. For this purpose, it includes nozzles, a supply pump connected to the nozzles, and a filter to remove any solid particles that may be present in the lubricant.

[0022] The inlet portion of the wheel conventionally comprises a gutter having an opening through which the lubricant jet enters the wheel, the gutter possibly being subdivided by partitions into several supply pockets.

[0023] In this configuration of the wheel, in which the feed pockets are open in the enclosure receiving the reducer, solid particles, for example from a worn part also received in the enclosure or transmitted to the lubricant by the motor in the case of a bypass of the filter of the lubrication group, may then enter the wheel, mix with the lubricant and wear down the lubricated parts of the reducer. Description of the invention

[0024] The invention aims in particular to overcome this drawback.

[0025] The invention proposes for this purpose a mechanical reducer with planetary elements, for aircraft turbomachine, provided with a lubrication device comprising a centrifugal wheel having a lubricant distribution circuit from an input portion of said centrifugal wheel to said reducer, said wheel being integral with a rotating planetary element of said reducer.

[0026] Said distribution circuit includes at least one pipe equipped with a filter screen for said lubricant, a through hole being made in a wall of said pipe in the vicinity of said screen and upstream of said screen following the flow of said lubricant.

[0027] Thus, the lubrication device has an integrated filtration system to prevent solid particles present in the lubricant from reaching the parts to be lubricated in the reducer, while preserving a reliable supply of lubricant since the risk of clogging the strainer is limited thanks to the through drilling made in the wall of the pipe.

[0028] According to another feature, said pipeline has a radial portion extending from said inlet portion and an axial portion extending transversely from said radial portion, said strainer having a generally cylindrical shape and having a mounting portion and a filtration portion projecting longitudinally from said mounting portion, said mounting portion being received in said radial portion.

[0029] According to yet another feature, said pipeline has a radial portion extending from said inlet portion and an axial portion extending transversely from said radial portion, said strainer having a generally cylindrical shape and having a mounting portion and a filtration portion projecting longitudinally from said mounting portion, said mounting portion being received in said axial portion.

[0030] Advantageously, said filter portion protrudes at least partially into said radial portion, said drilling being made in said radial portion.

[0031] Furthermore, said drilling opens opposite said filtration portion.

[0032] According to an additional feature, said drilling is oriented substantially perpendicular to said radial portion.

[0033] According to another feature, said drilling is oriented in a direction inclined towards said axial portion and towards said inlet portion.

[0034] According to yet another feature, said radial portion of the pipeline has a blind terminal section extending beyond the junction between the radial portion and the axial portion, said drilling opening into said blind terminal section.

[0035] The invention also relates to an aircraft turbomachine, comprising an input shaft, an output shaft and a mechanical reducer as defined above, mounted between said input and output shafts. Brief description of the drawings

[0036] Other purposes, advantages and features will become apparent from the following description, given for illustrative purposes only and made with reference to the accompanying drawings on which:

[0037] Fig. 1 is a schematic axial cross-sectional view of a turbomachine equipped with a planetary element reducer.

[0038] Fig. 2 is a schematic elevation view of the reducer of Fig. 1.

[0039] Figure 3 is a perspective view of a reducer similar to that shown in the [Fig.2] and equipped with a centrifugal wheel.

[0040] Fig. 4 is a perspective and sectional view of part of a lubrication device according to the invention, including a centrifugal wheel similar to that of Fig. 3.

[0041] [Fig.5] is a cross-sectional view along the section of [Fig.4].

[0042] Fig. 6 and Fig. 7 are schematic views similar to Fig. 5, illustrating variants of the lubrication device. DETAILED DESCRIPTION

[0043] Figure [1] shows a turbomachine, here a turbojet for aircraft, designated by the general numerical reference 1, with longitudinal axis XX.

[0044] This turbomachine 1 is a double-flow turbojet which includes at the front, considering the direction of the airflow admitted into the turbojet, a fan 2 which is connected to a reducer 3, a low-pressure compressor 4, and then a high-pressure compressor 5.

[0045] The turbomachine 1 also includes a combustion equipment comprising an annular combustion chamber 6, and downstream, a high-pressure turbine 7 and a low-pressure turbine 8.

[0046] The hot gases from the combustion pass through the high-pressure turbines 7 and low-pressure turbines 8 before escaping through an exhaust nozzle 9.

[0047] The high-pressure compressor 5 and the high-pressure turbine 7 are connected by a high-pressure shaft 11. The low-pressure compressor 4 and the low-pressure turbine 8 are connected by a low-pressure shaft 10. The blower 2 is driven by a blower shaft 12 which is driven by the low-pressure shaft 10 by means of the reducer 3.

[0048] The high-pressure compressor 5 compresses and sends fresh air from outside, from the front of the aircraft, to the combustion chamber 6 located approximately in the center of the turbomachine 1.

[0049] After combustion, the low-pressure compressor 4, downstream, transforms the ejection velocity of the hot air exiting the combustion chamber 6 into rotational power of the low-pressure turbine 8. This ejected air drives the blades of the low-pressure turbine 8 which reduces the pressure of this air to a low pressure at the engine outlet.

[0050] This low-pressure turbine 8 drives the low-pressure shaft 10 through the turbomachine 1 to drive the blower shaft 12 by means of the reduction gear 3, and thus the blower 2. The blower 2 at the inlet / front of the turbomachine sends air to the high-pressure compressor 5.

[0051] The following description relates essentially to reducer 3.

[0052] The reducer 3 illustrated in figures 2 and 3 comprises a central pinion 12, called solar, which is driven by a motor shaft which receives the motor torque, a ring gear 13, which transmits the torque, at the output to the blower shaft, and pinions 14 called satellites which are meshed between the solar gear 12 and the ring gear 13.

[0053] The reducer 3 further includes a satellite carrier 18 ensuring the retention of the satellites 14.

[0054] The solar element 12, the crown 13 and the satellite carrier 18 are planetary elements because their axis of revolution coincides with the longitudinal axis X of the turbomachine 1.

[0055] The satellites 14 have different axes of revolution distributed over the same operating diameter around the axis of the planetary gears. These axes are parallel to the longitudinal axis X.

[0056] The reducer 3 illustrated here is an epicyclic gear train, that is to say that the ring 13 is fixed and the planet carrier 18 constitutes the output shaft of the turbomachine 1, here the blower shaft, which rotates in the same direction as the solar 12.

[0057] With reference to [Fig.3], the satellite carrier 18 comprises a cylindrical body 15 coupled to the blower shaft, an annular wall 17 connected to a longitudinal end of the body 15, and parallel shafts 16 projecting axially (along the axis XX) from the annular wall 17 and on which the satellites 14 are rotatably mounted.

[0058] The shafts 16 are regularly distributed around the X axis of rotation of the satellite carrier 18 and are fixed to the annular wall 17.

[0059] The reducer 3 further includes a lubrication device which ensures the lubrication of the gears between the planetary gears and the satellites and / or the satellite bearings and which includes a centrifugal distributor consisting of a centrifugal wheel 20 attached and fixed to the distal ends of the shafts 16 opposite the annular wall 17.

[0060] The wheel 20 is integral with the satellite carrier 10, notably due to its connection to the shafts 16 supporting the satellites 14. The wheel 20 is therefore intended to be placed in rotation in operation around the X axis while being attached to the rotor of the reducer 3, in particular to the blower shaft.

[0061] The wheel 20 has an inlet portion configured to receive lubricant, here in the form of a jet, and a lubricant distribution circuit from the inlet portion to components to be lubricated of the reducer 3 including in particular the bearings mounted between the shafts 16 and the satellites 14, as well as the meshing teeth of the satellites 14 and the sun gear 12 and / or of the satellites 14 and the ring gear 13.

[0062] The wheel 20 is generally annular, with axis X.

[0063] The inlet portion of the wheel 20 has an annular gutter 19 located on the inner periphery of the wheel 20 and opening radially inwards, i.e. towards the X axis.

[0064] The wheel 20 further comprises a plurality of mounting lugs 21, here five in number, extending radially from the gutter 19 and being integral with the gutter 19 so as to form with it a star-shaped body 25.

[0065] The body 25 of the spinning wheel 20 is here formed from a single piece. Alternatively, the body of the spinning wheel results from the assembly of at least two pieces.

[0066] The mounting lugs 21 each carry at their end a mounting element for the wheel 20 with the planet carrier 18, which element will be detailed later with reference to figures 4 and 5.

[0067] Channels are further provided, for example by boring, in the mounting lugs 21 so that each mounting lug 21 forms a conduit of the distribution circuit. In an alternative embodiment not shown, the conduit may, for example, be formed by a cylindrical pipe separate from the mounting lug.

[0068] Here, each mounting lug 21 forms a channel, the impeller 20 thus comprising five channels. These channels are of a first type and are intended for the lubrication of the bearings mounted between the shafts 16 and the planetary gears 14.

[0069] The circuit also includes channels 22 of a second type, intended for the lubrication of the meshing teeth of the satellites 14 and the solar 12 and / or of the satellites 14 and the ring 13.

[0070] Lubricant jets (not shown), carried by a stator of the reducer 3 or of the turbomachine, are arranged radially inside the wheel 20 and project lubricant directly into the trough 19 of the wheel 20 to supply the circuit.

[0071] The lubricant is brought to the nozzles by a pump of a lubrication unit of the turbomachine (not shown), which delivers a predetermined flow of lubricant to the nozzles.

[0072] By centrifugal force, the lubricant projected into the trough is distributed throughout the circuit and carried to the bearings mounted between the shafts 16 and the satellites 14, as well as to the meshing teeth of the satellites 14 and the solar 12. The impeller 20 is thus a centrifugal wheel which distributes lubricant under pressure in the reducer 3 under the action of centrifugal forces generated during operation.

[0073] Figures 4 and 5 illustrate a 200 spinning wheel similar to that of [Fig.3].

[0074] The spinning wheel 200 differs in particular from the spinning wheel 20 described above in that, According to the invention, at least one of the pipes 210 is equipped with a lubricant filter screen 23, a through hole 24 being made in the wall of this pipe 210 in the vicinity of the screen 23 and upstream of the screen 23 in the direction of the lubricant flow. In other words, the hole 24 is located in the portion of the circuit between the channel 190 and the screen 23.

[0075] It should be noted that the following description of this 210 pipe is valid for the other four 210 pipes which are identical here.

[0076] The pipe 210 has a radial portion 26 extending from the inlet portion, here more precisely from the bottom of the gutter 190, and an axial portion 27 extending transversely from the radial portion 26 to a distal end through which the pipe 210 opens. The pipe 210 thus has an L-shape.

[0077] The pipe 210 opens into the bottom of the gutter 190. The gutter 190 is here subdivided into several pockets by walls 28 ([Fig.4]), each pipe 210 opening into a respective pocket.

[0078] The strainer 23 generally has a cylindrical shape and has a tubular mounting portion 29 and a filtration portion 30 projecting longitudinally from the mounting portion 29.

[0079] The strainer 23 is received in the pipe 210 with its filtration portion 30 upstream of the mounting portion 29, following the direction of the lubricant flow.

[0080] The mounting portion 29 is fixed to the pipe 210, here by screwing. Alternatively, the mounting portion is, for example, welded to the pipe.

[0081] The mounting portion 29 is received in the axial portion 27. It is here entirely received in the axial portion 27. The filtration portion 30 protrudes, here partially, into the radial portion 26.

[0082] The filtration portion 30 comprises a curved filtration wall, the convexity of which is turned towards the side opposite the mounting portion 29.

[0083] To install the strainer 23 in the pipe 210, the strainer 23 is introduced, by its filtration portion 30, into the distal end of the axial portion 27.

[0084] The drilling 24 is carried out in the radial portion 26.

[0085] The radial portion 26 has a blind terminal section 31 extending beyond of the junction between the radial portion 26 and the axial portion 27, the bore 24 being carried out at the level of terminal section 31 and leading into terminal section 31, here at the end of the cul-de-sac.

[0086] The bore 24 is oriented radially, along its longitudinal extension axis. The bore 24 and the radial portion 26 are also coaxial here.

[0087] In practice, the bore 24 is dimensioned so as to allow both the evacuation of particles present in the lubricant without however causing a leakage flow capable of degrading the performance of the lubrication device.

[0088] The diameter of the bore 24 is thus less than 25% of the internal diameter of the axial portion 27.

[0089] The mounting element of the wheel to the planet carrier, carried by the mounting lug 210, comprises a cylindrical barrel 32 extending axially from the radial portion 26 and configured to engage in a hollow of complementary shape of a shaft 16 of the corresponding planet carrier 18, an O-ring sealing between the cylindrical barrel 32 and the shaft 16.

[0090] The shaft 32 extends around and radially at a distance from the axial portion 27 of the pipeline 210. The axial portion 27 therefore partially protrudes into the shaft 32.

[0091] The wheel 200 further comprises mounting fingers 220 projecting radially from the gutter 190, between two mounting lugs 210. Channels are provided, for example by boring, in these mounting fingers 220 so that each mounting finger 220 forms a second type conduit of the distribution circuit, the body of the mounting finger thus forming the wall of the respective second type conduit.

[0092] The mounting fingers 220 are configured to carry nozzles extending the corresponding second type conduit to the meshing teeth of the satellites 14 and the solar 12.

[0093] The wheel 200 further comprises mounting lugs projecting radially from the trough 190 and arranged on either side of the mounting fingers 220. Each mounting lug has an opening for the passage of a screw for fixing it to the planet carrier. The mounting lugs and the screws thus form elements for securing the wheel 200 to the planet carrier.

[0094] Fig. 6 illustrates variants A, B, C of drilling orientation 24A, 24B, 24C in a conduit 210' similar to that of figures 4 and 5.

[0095] In this embodiment, the radial portion 26 of this pipe 210' is devoid of a blind terminal section, and the axial portion 27 of this pipe 210' is not projecting into the shaft 32.

[0096] Here, the drilling 24A, 24B, 24C is in the immediate vicinity of the strainer 23 and opens opposite the filtration portion 30.

[0097] In the first variant A, the bore 24A is oriented substantially perpendicular to the radial portion 26. In addition, the bore 24A is coaxial with the longitudinal extension axis of the strainer 23.

[0098] In the second and third variants B and C, the bore 24B, 24C is oriented in an inclined direction towards the axial portion 27 and towards the inlet portion 190. In the third variant C, the inclination of the bore 24C is also substantially the same with respect to the axial portion 27 and with respect to the radial portion 26.

[0099] Figure 7 illustrates a fourth variant of the arrangement of the strainer 23 and the bore 24D in the pipe 210', in which the mounting portion 29 is received in the radial portion 26 of the pipe 210'. The bore 24D is oriented substantially perpendicular to the radial portion 26.

[0100] In this case, for the installation of the strainer 23 in the pipe 210', a radial bore 33 is made at the junction of the radial portion 26 with the axial portion 27, in the extension of the radial portion 26. The strainer 23 is then introduced, by its filtration portion 30, into the radial bore 33. The strainer 23 is then fixed, and then the radial bore 33 is plugged.

[0101] It should be noted that in the described embodiments, the bore 24, 24A-D is in a geometric plane defined by the axial and radial portions of the pipe. In an alternative not shown, the bore is in a plane defined by the radial portion and transverse to the axial portion. Furthermore, the bore is oriented so as to open on the side of the pipe that is rearward with respect to the direction of rotation of the impeller, so as to evacuate the lubricant in the opposite direction to the rotation.

[0102] In some embodiments, the lubrication device equipped with the impeller 200 described above equips the reducer of the turbomachine illustrated in [Fig.1].

[0103] In other variants not shown:

[0104] Pipes of the second type are also equipped with strainers and orifices arranged in a similar manner to the strainers and orifices of pipes of the first type.

[0105] The wheel has more or less than five channels, for example three or six.

[0106] The mechanical reducer is multi-stage.

[0107] The reducer is differential.

[0108] The teeth of the planetary gears and / or satellites are straight or chevron.

Claims

Demands

1. Mechanical planetary element reducer for aircraft turbomachine, provided with a lubrication device comprising a centrifugal impeller (200) having a lubricant distribution circuit from an inlet portion (190) of said centrifugal impeller (200) to said reducer, said impeller being integral with a rotating planetary element (18) of said reducer (3), characterized in that said circuit comprises at least one channel (210; 210') equipped with a strainer (23) for filtering said lubricant, a through bore (24; 24A-D) being made in a wall of said channel (210; 210') in the vicinity of said strainer (23) and upstream of said strainer (23) following the flow of said lubricant.

2. Reducer according to claim 1, wherein said pipe (210') has a radial portion (26) extending from said inlet portion (190) and an axial portion (27) extending transversely from said radial portion (26), said strainer (23) having a generally cylindrical shape and having a mounting portion (29) and a filtration portion (30) projecting longitudinally from said mounting portion (29), said mounting portion (29) being received in said radial portion (26).

3. Reducer according to claim 1, wherein said pipe (210) has a radial portion (26) extending from said inlet portion (190) and an axial portion (27) extending transversely from said radial portion (26), said strainer (23) having a generally cylindrical shape and having a mounting portion (29) and a filtration portion (30) projecting longitudinally from said mounting portion (29), said mounting portion (29) being received in said axial portion (27).

4. Reducer according to claim 3, wherein said filtration portion (30) extends at least partially into said radial portion (26), said drilling (24; 24A-D) being made in said radial portion (26).

5. Reducer according to claim 3 or 4, wherein said drilling (24A-D) opens opposite said filtration portion (30).

6. Reducer according to any one of claims 3 to 5, wherein said bore (24; 24A; 24D) is oriented substantially perpendicular to said radial portion (26).

7. Reducer according to any one of claims 3 to 5, wherein said bore (24B; 24C) is oriented in a direction inclined towards said axial portion (27) and towards said inlet portion (190).

8. Reducer according to claim 3 or 4, wherein said radial portion (26) of the pipeline (210) has a blind terminal section (31) extending beyond the junction between the radial portion (26) and the axial portion (27), said bore (24) opening into said blind terminal section (31).

9. Aircraft turbomachine (1), comprising an input shaft, an output shaft and a mechanical reducer according to any one of claims 1 to 8 mounted between said input and output shafts.

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