Mechanical speed reducer

Abstract

The invention relates to a mechanical speed reducer for a turbomachine, in particular for an aircraft, comprising: - a sun gear extending around an axis of rotation (61), - a crown extending around the sun gear and configured to be fixed against rotation around the axis (61), - planet gears meshing with the sun gear and the crown and held by a planet carrier (62) configured to be able to move in rotation around the axis (61), furthermore, an oil distributor (65) comprising a plurality of oil distribution modules (67) assembled together, each module (67) comprising at least one lubrication duct (68) having an inlet intended to receive oil and an outlet (69) adapted to introduce the oil into openings (63) of the planet carrier (62) for lubricating the speed reducer.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of mechanical reducers for turbomachines, in particular aircraft turbomachines. BACKGROUND

[0002] In a known manner, the role of a mechanical reducer is to change the speed ratio and the torque ratio between the input shaft and the output shaft of a mechanical system.

[0003] A new generation of bypass turbomachines, in particular with a high bypass ratio, comprise a mechanical reducer to drive the shaft of the fan. Generally, the purpose of the reducer is to convert the rotational speed of the shaft of the power turbine, called fast rotation speed, into a slower rotational speed of the shaft driving the fan.

[0004] Such a reducer comprises a central pinion called sun gear, a crown and pinions called planet gears, which are engaged between the sun gear and the crown. The planet gears are held by a frame called planet carrier. The sun gear, the crown and the planet carrier are planetary because the axes of rotation of the sun gear, the crown and the planet carrier coincide with the longitudinal axis X of the turbomachine. The planet gears each have a different axis of rotation which are uniformly distributed on the same operating diameter around the axis of the planetary device. These axes are parallel to the longitudinal axis X.

[0005] There are various architectures of reducers. In the prior art bypass turbomachines, the reducer is planetary or epicyclic. In other similar applications, there are architectures called differential or compound.

[0006] • On a planetary reducer, the planet carrier is stationary and the crown constitutes the output shaft of the device which rotates in the opposite direction to the sun gear.

[0007] • On an epicyclic reducer, the crown is stationary and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the sun gear.

[0008] • On a differential reducer, no element is fixed in rotation. The crown rotates in the opposite direction to the sun gear and the planet carrier.

[0009] The reducer can consist of one or more meshing stages. This meshing is ensured in different ways, for example by contact, by friction or by a magnetic field.

[0010] There are various types of contact meshing, for example straight teeth, helical teeth or V-shaped teeth.

[0011] The reduction gear requires oil to lubricate and cool the gears, splines, rollers and bearings. In the case of a rotating planet carrier, the oil at the bearing or gear mesh of the planet gears must be applied in the rotating field. It is therefore necessary to transfer the oil from a reservoir located on the stator part to the rotating planet carrier. This transfer is usually carried out by an oil transfer bearing (OTB).

[0012] The present invention proposes a simple, effective and economic improvement to this technology. SUMMARY

[0013] According to a first aspect, the invention proposes a mechanical reduction gear for a turbomachine, in particular an aircraft, comprising:

[0014] - a sun gear having a rotation axis,

[0015] - a crown extending around the sun gear and configured to be fixed against rotation around said axis,

[0016] - planet gears meshing with the sun gear and the crown and held by a planet carrier configured to move in rotation around said axis (61),

[0017] - a lubrication oil distributor.

[0018] Furthermore, the oil distributor comprises a plurality of individual oil distribution modules, said modules being assembled outside the planet carrier to form together the distributor 65, each module comprising at least one lubrication duct having an inlet intended to receive oil and an outlet adapted to introduce the oil into an opening of the planet carrier for lubricating the reduction gear.

[0019] In a particularly advantageous manner, the distributor according to the invention makes it possible to supply oil to the rotating field. The modular structure of the distributor makes this contribution have almost no impact on the structure, while being easy to install.

[0020] Each module can comprise a plurality of ducts.

[0021] The plurality of ducts of the same module can have different diameters.

[0022] The plurality of ducts of the same module can have at least two different orientations.

[0023] The planet carrier can have a plurality of openings uniformly distributed.

[0024] The planet carrier comprises a plurality of openings, the number of which is limited to n times the number of planet gears.

[0025] The distributor is held between the planet carrier and the nut.

[0026] The outlet of each duct can comprise sealing means comprising at least one O-ring seal which enables to ensure the sealing of the connection of the outlet with each respective opening.

[0027] The sealing means can comprise a combination of two O-ring seals and a radial labyrinth, or comprise a coil comprising a double O-ring seal and a collar.

[0028] According to another aspect, the application relates to a method for assembling a reduction gear according to the application. The method comprises at least the following steps:

[0029] - positioning the nut on the axis;

[0030] - introducing the distal end into the respective opening of the planet carrier;

[0031] - rotating each module so as to assemble the modules to each other between the planet carrier and the nut;

[0032] - tightening the nut. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other features, objects and advantages of the application will appear from the following description, which is merely illustrative and non-limiting, and should be read in conjunction with the attached drawings, in which:

[0034] Figure 1 is a schematic axial cross-section view of a turbomachine using the application.

[0035] Figure 2 is a perspective view of a reduction gear according to the application.

[0036] Figure 3 is a view of a distributor according to the application.

[0037] Figure 4 is a perspective view of a module of a distributor according to the application.

[0038] Figure 5 is a view of an outlet of a duct of a distributor according to an embodiment of the application.

[0039] Figure 6 is a view of an outlet of a duct of a distributor according to an embodiment of the application.

[0040] Figure 7 is a view of an outlet of a duct of a distributor according to an embodiment of the application.

[0041] Figure 8 is a schematic view of the steps of assembling a reduction gear according to the application.

[0042] Figure 9is a schematic view of the steps of assembly of a reduction gear according to the application.

[0043] Figure 10 is a schematic view of the steps of assembly of a reduction gear according to the application.

[0044] Figure 11 is a schematic view of the steps of assembly of a reduction gear according to the application. DETAILED DESCRIPTION

[0045] Turbomachine

[0046] Figure 1 A turbomachine 1 is described, which generally comprises a fan S, a low-pressure compressor la, a high-pressure compressor lb, an annular combustion chamber lc, a high-pressure turbine Id, a low-pressure turbine le and an exhaust nozzle lh. The high-pressure compressor lb and the high-pressure turbine Id are connected by a high-pressure shaft 2 and form a high-pressure body (HP) with the high-pressure shaft. The low-pressure compressor la and the low-pressure turbine le are connected by a low-pressure shaft 3 and form a low-pressure body (LP) with the low-pressure shaft.

[0047] The fan S is driven by a fan shaft 4, which is driven by the shaft LP 3 through a reduction gear 6. This reduction gear 6 is generally epicyclic or cycloidal.

[0048] Reduction gear

[0049] With reference to Figure 2 , the reduction gear 6 comprises:

[0050] - a sun gear having an axis of rotation 61,

[0051] - a crown extending around the sun gear and configured to be fixed against rotation around said axis 61,

[0052] - a planet gear meshing with the sun gear and the crown and held by a planet carrier 62 configured to be rotationally mobile around said axis 62,

[0053] - a lubricating oil distributor 65.

[0054] Furthermore, the oil distributor 65 comprises a plurality of oil distribution modules 67 assembled together, each module 67 comprising at least one lubricating duct 68 having an inlet intended to receive oil and an outlet 69 adapted to introduce the oil into an opening 63 of the planet carrier 62 for lubricating the reduction gear.

[0055] In a particularly advantageous manner, the distributor according to the application makes it possible to supply oil to the rotating field. The modular structure of the distributor makes this contribution have little impact on the structure, while being easy to install.

[0056] Preferably, the planet carrier 62 has a plurality of openings 63 evenly distributed. Preferably, the planet carrier 62 comprises a plurality of openings, the number of which is defined as n times the number of the planet gears.

[0057] According to a preferred arrangement, the planet carrier 62 is made in one piece.

[0058] Distributor

[0059] The distributor 65 makes it possible to ensure the fluid connection between the OTB 9 and the planet carrier 62. In other words, the distributor 65 makes it possible to transfer oil from the OTB 9 to the planet carrier 62.

[0060] As mentioned previously, the distributor 65 comprises a plurality of modules 67 assembled together. In other words, the distributor 65 is a kit composed of a plurality of individual modules 67 assembled together to form the distributor 65.

[0061] Each module 67 comprises at least one duct 68 making it possible to introduce oil into the planet carrier 62. As illustrated, each module 67 can have a plurality of ducts 68. As Figure 3 and Figure 4 illustrated, the different ducts 68 of the same module 67 can have different orientations. Likewise, the plurality of ducts 68 of the same module 67 can have different diameters. Generally, the diameter of the ducts 68 can be determined by the amount and pressure of oil that must pass through the ducts.

[0062] As mentioned previously, each duct 68 has an outlet 69 intended to be introduced into the corresponding opening 63 of the planet carrier. The outlet 69 can comprise a sealing device comprising at least one O-ring seal 72 making it possible to ensure the sealing of the connection of the outlet 69 with the opening 63.

[0063] According to another embodiment illustrated in Figure 5 and Figure 6 , the sealing device can comprise a combination of two O-ring seals 72 and a radial labyrinth 75. The O-ring seals 72 make it possible to guarantee the sealing between the outlet 69 and the outside. The labyrinth 75 ensures the sealing between the various ducts 68.

[0064] According to another embodiment illustrated in Figure 7In another embodiment shown, the outlet 69 can have a combination of two O-ring seals 72 and a radial labyrinth 75, or have a coil 76 comprising a double O-ring seal 77 and a collar 78. The coil 76 can be arranged to be embedded in a portion of the cylinder of the outlet 69 and be sealingly connected to the outlet 69 by the double O-ring seal 77. The coil is constricted in the opening 63, which also enables the tightness of the connection to be guaranteed. This arrangement enables the sealing and mechanical strength to be combined. The constriction is a particularly advantageous arrangement, since this connection requires almost no mechanical means, while being sufficiently strong. In fact, as mentioned above, the distributor 65 exerts very little force on the planet carrier 62. In this case, the constriction is therefore a sufficient and particularly suitable connection solution.

[0065] Furthermore, the different modules 67 can be assembled to one another by means of bolts.

[0066] Preferably, the distributor 65 is held between the planet carrier 62 and the nut 79.

[0067] This solution enables the structural components to be completely distinguished from the oil circuit components, so that the materials, manufacturing methods and geometries can be freely chosen, without adding additional axial bulk. In general, the modules of the distributor 65 can be produced by additive manufacturing.

[0068] Assembly method

[0069] According to another aspect, the application provides a method for assembling a reduction gear 6 according to the application.

[0070] The method can comprise at least the following steps:

[0071] - positioning the nut 79 on the axis 61 ;

[0072] - introducing the distal portion 69 into the respective opening of the planet carrier 62;

[0073] - rotating each module 67 so that the modules are assembled to one another between the planet carrier 62 and the nut 79;

[0074] - tightening the nut 79.

[0075] More specifically, with reference to Figure 8 , the nut 79 is first screwed onto the OTB 9.

[0076] Then, as shown in Figure 9 , the nut 79 and OTB 9 assembly is engaged on the planet carrier 62.

[0077] Then, each module 67 is engaged in the planet carrier 62. As shown in Figure 10 , each module is engaged obliquely, that is to say, in a direction that intersects the axial direction and the radial direction.

[0078] Then, with reference to Figure 11 Each module is then bent so that the outlet 69 engages in the opening 63 and ensures the fluid connection between the OTB 9 and the planet carrier 62.

[0079] Finally, the nut 79 is tightened to ensure that the module 67 is retained.

[0080] The modules 67 can also be connected to each other with bolts.

[0081] It should therefore be understood that the modular structure of the distributor 65 enables simple assembly, which does not require disassembly of the planet carrier 62.

Claims

1. A mechanical reducer (6) for a turbomachine, the mechanical reducer (6) comprising: - a sun gear extending around an axis of rotation (61), - a crown extending around the sun gear and configured to be fixed against rotation around the axis (61), - planet gears meshing with the sun gear and the crown and held by a planet carrier (62) configured to be able to move in rotation around the axis (61), - a lubricating oil distributor (65), characterized in that the oil distributor (65) comprises a plurality of separate oil distribution modules (67) assembled to one another outside the planet carrier to form together the distributor (65), each module (67) comprising at least one lubricating duct (68) having an inlet intended to receive oil and an outlet (69) adapted to introduce oil into an opening (63) of the planet carrier (62) for lubricating the reducer.

2. The mechanical speed reducer (6) according to claim 1, wherein, Each module (67) comprises a plurality of ducts (68).

3. The mechanical speed reducer (6) according to claim 2, wherein, The plurality of ducts (68) of the same module (67) have different diameters.

4. The mechanical speed reducer (6) according to claim 2 or 3, wherein The plurality of ducts (68) of the same module (67) have at least two different orientations.

5. The mechanical speed reducer (6) according to any one of claims 1 to 3, wherein, The planet carrier (62) has a plurality of openings (63) distributed uniformly.

6. The mechanical speed reducer (6) according to claim 5, wherein, The planet carrier (62) comprises a plurality of openings (63) the number of which is defined as n times the number of planet gears.

7. The mechanical speed reducer (6) according to any one of claims 1 to 3, wherein, The outlet (69) of each duct (68) comprises a sealing device comprising at least one O-ring seal (72) making it possible to ensure the sealing of the connection of the outlet (69) with each corresponding opening (63).

8. The mechanical speed reducer (6) according to claim 7, wherein, The sealing device comprises a combination of two O-ring seals (72) and a radial labyrinth (75), or comprises a coil (76) comprising a double O-ring seal (77) and a collar (78).

9. The mechanical speed reducer (6) according to any one of claims 1 to 3, wherein, The distributor (65) is held between the planet carrier (62) and a nut (79).

10. The mechanical speed reducer (6) of claim 1, wherein, The turbomachine is an aircraft turbomachine.

11. Method for assembling a mechanical speed reducer (6) according to claim 9, characterized in that, The method comprises at least the following steps: - positioning the nut (79) on the axis (61); - introducing the outlet (69) into the corresponding opening (63) of the planet carrier (62); - rotating each module (67) to assemble the modules to one another between the planet carrier (62) and the nut (79); - tightening the nut (79).

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