Planetary gear reducer for an aircraft turbine engine and corresponding turbine engine

Abstract

The invention relates to a reducer which is provided with a ring gear which comprises at least one cylindrical body (21) having a first side face (23), a second side face (24) and an outer peripheral face (25) connecting the side faces, and at least one retaining ring (22) received in an annular groove (28) provided in the outer peripheral face.

Description

[0001] DESCRIPTION

[0002] TITLE: Planetary Gear Reducer for Aircraft Turbomachinery and Corresponding Turbomachinery

[0003] technical field

[0004] The invention relates to planetary gear reducers for aircraft turbomachinery and aircraft turbomachinery equipped with such reducers.

[0005] Previous techniques

[0006] The role of a mechanical reducer is to change the speed and torque ratio between the input and output shafts of a mechanical system.

[0007] 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.

[0008] Such a reducer includes a central pinion, called the solar pinion, which is driven by a drive shaft that 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.

[0009] The satellites are held by a frame called a satellite carrier. The solar array, the corona, and the satellite carrier are planetary because their axis of revolution coincides with the longitudinal X-axis of the turbomachine.

[0010] The satellites have different axes of revolution distributed over the same operating diameter around the axis of the planetary bodies.

[0011] These axes are parallel to the longitudinal axis X.

[0012] There are several gearbox architectures. In the state of the art of multi-flow turbomachinery, gearboxes are of the planetary or epicyclic type.

[0013] In other similar applications, there are so-called differential architectures.

[0014] On a planetary reducer, the planet carrier is fixed and the ring gear forms the output shaft of the device which rotates in the opposite direction to the sun.

[0015] On an epicycloidal reducer, the ring gear is fixed and the satellite carrier constitutes the output shaft of the device which rotates in the same direction as the sun gear.

[0016] On a differential gearbox, no element is fixed for rotation. The ring rotates in the opposite direction to the solar panel and the satellite carrier.

[0017] Gear reducers can be composed of one or more gear stages.

[0018] This meshing is achieved, for example, by contact, friction, or magnetic fields. There are several types of contact meshing, such as spur, helical, or herringbone gears.

[0019] In the case of a planetary or differential gearbox, the ring gear is a rotating part. During its rotation, the ring gear is loaded with kinetic energy, which, if the ring gear breaks, can generate high-energy debris that could pierce the housings and be ejected from the engine.

[0020] To solve this problem, it has already been proposed to reinforce the crown and / or the surrounding casing by increasing their dimensions, particularly their thickness. However, this leads to a significant increase in mass.

[0021] Description of the invention

[0022] The invention is specifically aimed at overcoming the aforementioned drawbacks.

[0023] The invention provides for this purpose a planetary gear reducer for an aircraft turbomachine, comprising a ring gear, a sun gear, and planet gears meshing between said sun gear and said ring gear. The ring gear comprises:

[0024] - at least one annular body having a first lateral face, a second lateral face axially opposite said first lateral face, and an external peripheral face between said first lateral face and said second lateral face; and

[0025] - at least one retention ring received in an annular groove formed in said external peripheral face of said annular body.

[0026] Thus, in the event of a break in the body, the pieces of the body tend to remain together, which reduces the risk of them being projected outwards, through the gearbox casing and escaping from the motor, damaging other motor components in the process.

[0027] According to another characteristic, said retention ring is flush with said first lateral face.

[0028] Advantageously, said groove and said retention ring extend axially over a major part of said external peripheral face.

[0029] According to another feature, said crown has two retention rings received in two respective annular grooves formed in said external peripheral face.

[0030] According to yet another characteristic, the crown comprises two stages, each comprising a body having an annular portion of toothed engagement equipped with at least one retention ring and a rim projecting radially from the annular portion of toothed engagement, the stages being connected by said rims.

[0031] According to another characteristic, said rim is equipped with at least one retention ring.

[0032] Advantageously, said retention ring extends axially over a major part of said external peripheral face.

[0033] Furthermore, said retention ring results from a winding of fibers made of a material comprising polymer, carbon, ceramic and / or metal, and / or results from a matrix and a winding of fibers embedded in said matrix.

[0034] Advantageously, the retention ring is formed by inserting a material different from that of the crown. The invention also relates to an aircraft turbomachine comprising a reduction gear as defined above.

[0035] Brief description of the drawings

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

[0037] The [Fig 1] is a schematic axial cross-sectional view of a turbomachine equipped with a planetary gear reducer according to the invention;

[0038] The [Fig 2] is a schematic elevation view of a reducer according to the prior art, which comprises a ring gear, a central pinion and satellite pinions meshing between the central pinion and the ring gear;

[0039] The [Fig 3] is a schematic cross-sectional and side view of a portion of the reducer ring of Figure 1;

[0040] Figures 4, 5 and 6 illustrate variant arrangements of the crown in Figure 3;

[0041] Figure 7 illustrates another embodiment of a crown according to the invention;

[0042] Figures [Fig 8], [Fig 9] and [Fig 10] illustrate variant arrangements of the crown in Figure 7;

[0043] Figure 11 illustrates a third embodiment of a crown according to the invention; and

[0044] Figures [Fig 12], [Fig 13] and [Fig 14] illustrate variant arrangements of the crown in Figure 11.

[0045] DETAILED DESCRIPTION

[0046] Figure 1 shows a turbomachine, here a turbojet for aircraft, designated by the general numerical reference 1, with longitudinal axis X.

[0047] This turbomachine 1 is a double-flow turbojet which has at the front, considering the direction of the airflow admitted into the turbojet, a fan 2 which is connected to a reducer 3 which drives in rotation a low pressure compressor 4, then a high pressure compressor 5.

[0048] The turbomachine 1 also includes a combustion unit comprising an annular combustion chamber 6, and downstream, a high-pressure turbine 7 and a low-pressure turbine 8.

[0049] The hot gases from combustion pass through the high-pressure turbines 7 and low-pressure turbines 8 which drive the blower before escaping through an exhaust nozzle 9.

[0050] The low-pressure compressor and the low-pressure turbine are connected by a low-pressure shaft 10. The high-pressure compressor and the high-pressure turbine are connected by a high-pressure shaft 11. The blower is driven by a blower shaft 12 which is driven by the low-pressure shaft by means of the reducer 3.

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

[0052] For a proper understanding of the invention, the reducer 3 has been schematically represented in Figure 2 in a configuration according to the prior art.

[0053] The reducer 3 illustrated in Figure 2 includes a central pinion 15, called the solar pinion, which is driven by a drive shaft which receives the drive torque, a ring gear 13, which transmits the output torque to the blower shaft, and pinions 14 called satellites which are meshed between the solar pinion 15 and the ring gear 13.

[0054] The reducer 3 also includes a satellite carrier 18 (partially visible) which ensures the retention of the satellites 14, here by means of shafts 16.

[0055] The solar element 15, the corona 13 and the satellite carrier 18 are planetary elements because their axis of revolution coincides with the longitudinal axis X of the turbomachine 1.

[0056] The 14 satellites have different axes of revolution distributed over the same operating diameter around the planetary axis. These axes are parallel to the longitudinal X axis.

[0057] The reducer 3 illustrated here is a planetary gear train, that is to say that the planet carrier 18 is fixed and the ring 13 constitutes the output shaft of the turbomachine 1, here the blower shaft, which rotates in the opposite direction to the solar 15.

[0058] The satellite carrier 18 comprises a cylindrical body, an annular wall connected to a longitudinal end of the body, and parallel shafts 16 projecting axially (along the X-axis) from the annular wall, on which the satellites 14 are rotatably mounted. The satellite carrier 18 further comprises a flange (not shown) integral with the cylindrical body and connected to the fixed motor frame.

[0059] With reference to Figure 3, a cross-sectional view of a sector of the ring 13 of the reducer 3, now in a configuration according to the invention, has been shown.

[0060] The crown 13 comprises an annular body 21 and a retention ring 22.

[0061] The crown 13 further includes a flange (not illustrated) integral with the body 21 and intended to be coupled to the blower shaft.

[0062] The body 21 has a toothed annular meshing portion 30 and a peripheral rim 29 projecting axially and radially outwards from the meshing portion 30.

[0063] The body 21 has a first lateral face 23, a second lateral face 24 axially opposite to the first lateral face 23 and an external peripheral face 25 connecting the first lateral face 23 to the second lateral face 24.

[0064] The body 21 also has an internal peripheral face 26 radially opposite the external peripheral face 25.

[0065] The body 21 also has teeth 27, formed in the meshing portion 30, here on the internal peripheral face 26 of the body 21.

[0066] The rim 29 has a first portion 32 extending axially while being inclined radially outwards, and a second portion 33 extending the first portion 32 while being oriented transversely to the latter, here radially.

[0067] In the case of an epicyclic gear reducer, the planet carrier is connected to the output shaft of the turbomachine, such as the fan shaft 12 of the turbomachine 1. The planet carrier is similar to the planet carrier 18 and comprises a cylindrical body for coupling to the fan shaft, an annular wall connected to a longitudinal end of the body, and parallel shafts 16 projecting axially (along the X-axis) from the annular wall on which the planets 14 are rotatably mounted. The ring gear 13 is fixedly mounted in the turbomachine.

[0068] The body 21 also has an annular groove 28, formed in the external peripheral face 25, and in which the retention ring 22 is received.

[0069] The annular groove 28 is provided in the meshing portion 30 near the lateral face 23, at a non-zero distance from the latter, along the axial direction.

[0070] The retention ring 22 is fully received in the groove 28, flush with the external peripheral face 25. The groove 28 and the ring 22 have complementary cross-sectional shapes.

[0071] The retention ring 22 forms a reinforcement and is created by inserting a tear-resistant material, such as a metal or a polymer, into the groove 28. Alternatively, the reinforcement is created by winding a high-tear-strength fiber weave into the groove 28. The fibers are made of a material comprising a polymer, carbon, ceramic, and / or metal. Alternatively, this reinforcement further includes a matrix in which the fibers are embedded. This matrix is ​​made of a suitable material, such as a polymer, ceramic, or metal.

[0072] It should be noted that the retaining ring 22 is only attached to the body 21 by virtue of being engaged in the annular groove 28, that is, it is abutted against the bottom and the lateral walls axially opposite the groove 28. The retaining ring 22 therefore does not exert any stress on the body 21 when the latter is intact, in particular when it is intact in the radial direction. This prevents any crack appearing in the body 21 from propagating under the effect of such stress and worsening the fragmentation of the body 21. If, while the turbomachine is operating, the body 21 is broken, the retaining ring 22 keeps the fragments together, resisting the centrifugal force.

[0073] We will now describe, with reference to Figures 4 to 14, alternative embodiments of a gear reducer ring according to the invention. In these figures, elements identical to those described with reference to Figures 2 and 3 are designated by the same numerical references.

[0074] In the embodiment of figure 4, the crown, which is otherwise identical to the crown described previously, has a flush retaining ring 22 inserted or wound in a groove which extends to the lateral face 23. The groove 28 is thus, in addition, provided in the first lateral face 23, the retaining ring 22 being flush with the first lateral face 23.

[0075] In the embodiment of Figure 5, the crown has an integral reinforcement, the groove 28 and the retention ring 22 extending axially over a major part of the outer peripheral face 25. The groove 28 and the retention ring can, for example, extend over at least 50%, or over at least 60%, 70%, 80% or 90% of the outer peripheral face 25.

[0076] It should be noted that such an arrangement of the crown is particularly advantageous for limiting the propagation of any cracks inside the body of the crown, as well as for absorbing the forces that debris from the body would exert under the effect of centrifugal force.

[0077] The crown illustrated in Figure 6 has a double retaining ring and thus comprises a second annular groove 34 and a second retaining ring 35 received in the second groove 34. The second annular groove 34 and the second retaining ring 35, similar to the groove 28 and the ring 22, are formed in the meshing portion 30, near the second transverse face 24. The second annular groove 34 and the second retaining ring 35 are also near the rim 29, more precisely the inclined portion 32.

[0078] In the embodiment illustrated in Figure 7, the crown is a two-stage or double-helix crown and includes a second body 37 which comprises a second gear portion 31 and a second rim 36, similar to the gear portion 30 and the rim 29. The two bodies are connected head-to-tail by the rims 29 and 36.

[0079] The second body has a retention ring 22, identical to the retention ring of the first body 21, inserted or wound in an annular groove 28.

[0080] In the embodiment of figure 8, which corresponds to the embodiment of figure 4, the retention ring 22 is flush with the first lateral face 23 and, in the embodiment of figure 9, which corresponds to the embodiment of figure 5, the retention ring 22 extends axially over a major part of the external peripheral face 25.

[0081] The crown illustrated in figure 10 corresponds to the embodiment of figure 6. The second body 37 has two retaining rings 38, 39 respectively received in two grooves 40 and 41 formed in the meshing portion 31.

[0082] In the embodiment illustrated in Figure 11, the middle part of each rim has an L-shape, replacing the inclined shape 32 of the embodiment of Figures 3 to 10, and comprises a first arm 44 which extends radially outwards and a second axial arm 45 extended by the second portion 33.

[0083] With reference to Figure 12, the crown of Figure 11 can be provided with an additional retaining ring 42 inserted or wound into a corresponding groove 43, in the junction area between the first spoke 44 and the second spoke 45 of each corresponding rim 29, 36. Alternatively, this additional retaining ring is flush.

[0084] The crown illustrated in figure 13 is similar to the crown in figure 12 and has integral reinforcement. Thus, each retaining ring 22 and 42 extends axially over a major part of the meshing portion 30, 31 and the second axial branch 45 of each body 21, 37.

[0085] It should be noted that each meshing portion and each axial arm 45 can each be provided with a simple reinforcement, similar to the reinforcement in Figures 3 and 7, a flush reinforcement, similar to the embodiment in Figures 4 and 8, or even an integral reinforcement similar to the embodiment in Figures 5 and 9, or a double reinforcement (Figures 6 and 10). For example, the ring gear illustrated in Figure 14 is similar to the ring gear in Figure 13, but has a double reinforcement at the meshing portion 31.

Claims

DEMANDS 1. Planetary gear reducer for an aircraft turbomachine comprising a ring gear (13), a sun gear (15) and planet gears (14) meshing between said sun gear (15) and said ring gear (13), said reducer being characterized in that said ring gear (13) comprises: - at least one annular body (21, 37) having a first lateral face (23), a second lateral face (24) axially opposite said first lateral face, and an external peripheral face (25) between said first lateral face and said second lateral face; and - at least one retention ring (22, 35, 38, 39, 42) received in an annular groove (28, 34, 40, 41, 43) provided in said external peripheral face of said annular body.

2. Reducer according to claim 1, in which said retaining ring (22) is flush with said first lateral face (23).

3. Reducer according to claim 1 or 2, in which said groove (28; 42) and said retaining ring (22; 43) extend axially over a major part of said external peripheral face (25).

4. Reducer according to any one of claims 1 to 3, in which said ring comprises two retaining rings (22, 35) received in two respective annular grooves (28, 34) formed in said external peripheral face (25).

5. Reducer according to any one of claims 1 to 4, comprising two stages each comprising a body (21, 37) having an annular toothed meshing portion (30, 31) having at least one retaining ring (22) and a rim (29, 36) projecting radially from the annular toothed meshing portion, the stages being connected by said rims.

6. Reducer according to claim 5, wherein said rim is provided with at least one retaining ring.

7. Reducer according to claim 6, in which said retention ring (22) extends axially over a major part of said external peripheral face (25).

8. Reducer according to any one of claims 1 to 7, wherein said retention ring (22, 35, 38, 39, 42) results from a winding of fibers made of a material comprising polymer, carbon, ceramic and / or metal, and / or results from a matrix and a winding of fibers embedded in said matrix.

9. Reducer according to any one of claims 1 to 7, wherein said retaining ring (22, 35, 38, 39, 42) results from the insertion of a material different from that of said crown.

10. Aircraft turbomachine comprising a reduction gear (3) according to any one of claims 1 to 9.

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