Turbine engine including a reduction gear having an attachment flange connected with a stator of the turbine engine

Abstract

The invention relates to a reduction gear (20) for a turbine engine (1) of an aircraft, having a longitudinal axis X, wherein the reduction gear comprises an outer ring (24) and a ring carrier (26) attached to the outer ring, planet pinions meshing with sun pinions, and wherein the outer ring is formed by two front and rear ring halves (24a, 24b), and wherein the two ring halves each have a radially outwardly extending front (24ab) and rear (24bb) flange half, which are attached to an attachment flange (27) of the ring carrier, and wherein the ring carrier comprises a swan neck (28) which can center the ring. According to the invention, the attachment flange extends radially between the front (24ab) and rear (24bb) flange halves, and the swan neck has a C-shaped axial cross-section, the bottom (28a) of which is tangential to a radial plane (PR) upstream of the front mounting flange half.

Description

Technical Field

[0001] This invention relates to the general field of aviation. Specifically, this invention relates to a mechanical speed reducer having an attachment flange that is connected to the stator of a turbine engine. Background Technology

[0002] The function of a mechanical speed reducer is to change the speed ratio and torque ratio between the input and output shafts of a mechanical system.

[0003] New-generation twin-flow turbine engines (especially those with high bypass ratios) include a mechanical speed reducer to drive the fan shaft. The typical purpose of the speed reducer is to convert the rotational speed of the power turbine shaft (known as the high speed) to the slower rotational speed of the shaft driving the fan.

[0004] This reducer comprises a central pinion called the sun gear, a ring gear, and pinions called planetary gears, which engage between the sun gear and the ring gear. The planetary gears are held in place by a frame called the planet carrier. The sun gear, ring gear, and planet carrier are planetary gears because the axes of rotation of the sun gear, ring gear, and planet carrier coincide with the longitudinal axis X of the turbine engine. Each planetary gear has a different axis of rotation and they are evenly distributed around the axis of rotation on the same running circle. These axes are parallel to the longitudinal axis X.

[0005] There are multiple gearbox architectures. In the prior art of dual-flow turbine engines, the gearbox is planetary or rotary. In other similar applications, there are architectures referred to as differential or "compound".

[0006] • In a planetary gear reducer, the planet carrier is fixed, and the ring gear is the output shaft of the device, which rotates in the opposite direction to the sun gear.

[0007] • In a rotary reducer, the ring gear is fixed, and the planetary carrier is the output shaft of the device, which rotates in the same direction as the sun gear.

[0008] • In a compound gear reducer, no components are rotatably attached. The ring gear rotates in the opposite direction to the sun gear and planet carrier.

[0009] A speed reducer may include one or more engagement stages. This engagement is ensured in different ways, such as through contact, friction, or a magnetic field.

[0010] Examples of the reducer are described in documents EP3974677A1, EP3279507A1 and US2014 / 301829A1.

[0011] There are various types of contact engagement, such as spur teeth, spiral teeth, or herringbone teeth.

[0012] Figure 1 and Figure 2 A reducer 1A with a planetary gear is shown. Reducer 1A includes a fixed gear ring 2A connected to a stationary housing or stator 3A of a turbine engine via a gear ring carrier 4A. Reducer 1A includes planetary gears 5A that rotate a planetary carrier. The planetary carrier is attached to a fan shaft and is rotatable about the longitudinal axis of the turbine engine. Gear ring 2A includes a first attachment flange 7A extending radially outward and a second attachment flange 8A attached to gear ring carrier 4A via bolted connections. Attachment flanges 7A and 8A each include surfaces that are bolted together by bolts in the bolted connections. An example of a reducer is described in document FR-A1-3042568.

[0013] The gear ring 2A consists of two gear ring halves 2Aa and 2Ab, each including internal herringbone teeth that mesh with the external teeth of the planetary gear 5A. The two gear ring halves also include corresponding axial teeth 9A that mesh with each other, allowing force to be transferred from one gear ring half to the other during rotation. The two gear ring halves 2Aa and 2Ab are precisely positioned relative to each other using a locating pin, which also ensures the alignment of the internal herringbone teeth. An interference fit further ensures that the two gear ring halves are centered.

[0014] The gear ring carrier 4A has bellows to limit overload caused by displacement and misalignment of components in the turbine engine and to transmit high torque. The gear ring carrier 4A also includes a gooseneck 10A, which is also designed to ensure the gear ring is centered and limit misalignment. The gooseneck 10A typically has a small radius of curvature, generally forming a V-shape, and is tangent to a center plane P1 that passes between the two flange halves 11Aa and 11Ab of the gear ring half and is perpendicular to the longitudinal axis of the turbine engine. For example, the radius of curvature of this gooseneck is 5 mm, forming a 45° V-shape.

[0015] Torque transmission is achieved through friction between these surfaces and is limited to the uniform diameter region of the insert. Increasing the diameter of the attachment flange could be a solution to improve torque transmission capability. However, on the one hand, the number of screws that can be inserted into these flanges may be limited, and on the other hand, this could directly affect the diameter of the reducer and its integration within the already limited space of the turbine engine. Furthermore, the manufacture of this gear ring holder and gear ring is complex. The gear ring holder includes holes near the bellows for lubricant discharge, which complicates the manufacturing and assembly process. When installing or removing the gear ring holder and gear ring, the gooseneck obstructs access to many bolts in the bolted connection. Variations in the gooseneck result in variations in the stiffness of the gear ring holder, which could directly affect misalignment of the reducer.

[0016] Some or all of the above-mentioned drawbacks need to be addressed. Summary of the Invention

[0017] The purpose of this invention is to provide a solution that allows a gear ring to be easily connected to the stator of a turbine engine to transmit torque, and that the solution is simple and economical to manufacture and assemble, while ensuring optimized stiffness.

[0018] According to the present invention, this objective is achieved by a reduction gear for an aircraft turbine engine having a longitudinal axis. The reduction gear includes a sun pinion, planetary pinions, an external gear ring, and a gear ring carrier attached to the external gear ring. The planetary pinions mesh with the sun pinion on one side and with the external gear ring on the other side. The external gear ring is formed by two gear ring halves, each having a radially outwardly extending front mounting flange half and a rear mounting flange half. The two gear ring halves are attached to an attachment flange of the gear ring carrier by an attachment member. The gear ring carrier includes a gooseneck that centers the gear ring. The attachment flange extends radially between the front mounting flange half and the rear mounting flange half, and the gooseneck has a C-shaped axial section, the bottom of which is tangent to a radial plane located upstream of the front mounting flange half.

[0019] Therefore, this solution enables the achievement of the aforementioned objectives. Specifically, mounting the ring gear carrier flange between the two flange halves of the ring gear ensures uniform stiffness between the ring gear halves and between the ring gear and the turbine engine stator. In particular, stiffness is optimized. In fact, the optimized stiffness of the stator components in the turbine engine's reduction gear is determined by the need to ensure proper alignment and limit misalignment caused by internal meshing forces within the reduction gear and misalignment caused by the turbine engine.

[0020] The operation of this type of reducer requires the stator components to have an effective flexible device (optimized stiffness), so that: - Limit overload in the system caused by engine movement - Ensure the healthy dynamic condition of the entire gearbox and turbine engine components. - Transmitting important torque.

[0021] The gooseneck design also facilitates mounting on the gear ring, making the gear ring easier to move and allowing the mounting attachments and mounting flanges to pass through. The gooseneck configuration also improves the manufacturability of the gear ring holder. Furthermore, this arrangement is simple and requires no substantial changes to the reducer or stator.

[0022] The reducer also includes one or more of the following features, either individually or in combination: - The radius of curvature of the gooseneck is equal to 0.5 times the radial height of the front mounting flange half and the rear mounting flange half.

[0023] - The reducer includes a lubricant discharge device, which is arranged at least in the front mounting flange half and the rear mounting flange half.

[0024] - The discharge device includes a discharge port, which is at least partially formed in the walls of the front flange half and the rear flange half and extends radially.

[0025] - The front mounting flange half, the rear mounting flange half, and the attachment flange of the gear ring frame each include an axial attachment orifice, through which the attachment member passes. The axial attachment orifice is arranged circumferentially around the longitudinal axis.

[0026] - Attachment components include axial screws or bolts that pass through the orifice.

[0027] - The gear ring carrier includes a flexible device, such as at least one bellows.

[0028] - The gear ring holder includes a through hole that radially passes through both sides of the wall of the gear ring holder.

[0029] --The gear ring is connected to the housing of the turbine engine and cannot rotate relative to the longitudinal axis.

[0030] --The gear ring is connected to the shaft of the turbine engine and is able to rotate about the longitudinal axis.

[0031] The present invention also relates to an aircraft turbine engine having a longitudinal axis and a reduction gear as described above.

[0032] The present invention also relates to an aircraft equipped with such a turbine engine. Attached Figure Description

[0033] The invention will be better understood by reading the following detailed description of embodiments of the invention, given as purely illustrative and non-limiting examples, with reference to the illustrative drawings, in which: Figure 1 A mechanical speed reducer for a turbine engine according to the prior art is shown; Figure 2 An example of a gear ring according to the prior art is shown; Figure 3 An example of a turbine engine according to the present invention is shown; Figure 4 This is a detailed view of an example of a speed reducer according to the present invention; Figure 5This is a partial axial cross-sectional view of an embodiment of the reducer according to the present invention; Figure 6 This is a partial axial cross-sectional view of another embodiment of the reducer according to the present invention. Detailed Implementation

[0034] Figure 1 and Figure 2 The mechanical reducer, specifically the gear ring, which has been described and is configured to be fitted onto a turbine engine, is shown.

[0035] Figure 3 A turbine engine 1 with a longitudinal axis X is shown. The turbine engine 1 shown is a dual-flow, dual-body turbine engine 1 configured to be mounted on an aircraft. Of course, the turbine engine can be a single-flow turbojet engine or a turboprop engine equipped with a single non-ducted propeller or twin non-ducted, counter-rotating propellers (referred to as "open rotors"). The invention can be applied to other fields using mechanical reduction gears.

[0036] In this invention, the terms "upstream" and "downstream" are defined relative to the flow of gas in a turbine engine, here along the longitudinal axis X and... Figure 3 The middle is defined from left to right.

[0037] The turbine engine 1 conventionally comprises, from upstream to downstream, a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 2, a high-pressure turbine 3a, a low-pressure turbine 3b, and an exhaust nozzle 4. The high-pressure compressor 1b and the high-pressure turbine 3a are connected via a high-pressure shaft 5 and together form a high-pressure (HP) body. The low-pressure compressor 1a and the low-pressure turbine 3b are connected via a low-pressure shaft 6 and together form a low-pressure (BP) body.

[0038] The fan S is housed within the fan casing 7 that supports the outer nacelle 8. The fan S generates a primary airflow and a secondary airflow from the incoming airflow F. The primary airflow flows through a main duct 9 leading to the exhaust nozzle 4, while the secondary airflow flows through a secondary duct 10 surrounding the main duct 9 and leading to the injection nozzle 11. The primary and secondary airflows intersect and mix downstream.

[0039] The fan S is driven by a fan shaft 12, which is driven by a low-voltage shaft 6, for example by means of a reducer 20. The reducer 20 is typically a planetary or rotary type.

[0040] In this embodiment, the turbine engine is equipped with a reducer 20 (reduction gearbox (RGB)) consisting of a gear system.

[0041] According to the flow of gas in the turbine engine, the reduction gear 20 is positioned in the upstream portion of the turbine engine. A fixed structure 13, schematically including the upstream portion 13a and the downstream portion 13b, constitutes the engine housing 16 or stator and is arranged to form an enclosure 14 surrounding the reduction gear 20. For example, the engine housing 16 may be the intake housing of the turbine engine. Lubricating oil mist is present in the enclosure 14. The enclosure 14 is advantageously, but not limited to, sealed at the upstream bearing 15 through which the fan shaft 12 passes, and sealed downstream at the low-pressure shaft 6 passage.

[0042] refer to Figure 4 The reducer 20 is rotary. It comprises three components: a sun pinion 21, a planetary pinion 22, and a planet carrier 23, all of which are capable of rotational motion. The rotational speed of one of these components depends specifically on the speed difference between the other two components.

[0043] On the input side, the reducer 20 is connected to the low-pressure shaft 6, for example, via a spline 39. Advantageously, the spline 39 extends parallel to the longitudinal axis X. Thus, the low-pressure shaft 6 drives the sun gear 21 (or internal planetary gears). Typically, the sun gear 21, whose axis of rotation coincides with the longitudinal axis X of the turbine engine, drives planetary gears 22, which are evenly spaced on the same circumference around the longitudinal axis X. This diameter is equal to twice the distance between the running centers of the sun gear and the planetary gears. For this type of application, the number of planetary gears is typically limited to between three and seven.

[0044] Advantageously, the sun gear 21 is fixed to the low-pressure shaft 6 in terms of rotation, and the planet carrier 23 is fixed to the fan shaft 12 in terms of rotation.

[0045] The planetary gears 22 are held in place by a frame called the planet carrier 23. Each planetary gear 22 rotates about its own axis. Each planetary gear 22 meshes with an external ring gear 24 (or an external planetary gear).

[0046] The external gear ring 24 is fixed relative to the longitudinal axis X or fixed in terms of rotation.

[0047] On the output side, the planetary gear 22 drives the planetary carrier 23 to rotate about the turbine engine axis X. The external ring gear 24 is attached to the turbine engine housing or stator (e.g., housing 16) via the ring gear carrier 26 described below. The planetary carrier 23 is attached to and rotates-fixed to the fan shaft 12.

[0048] Optionally, each planetary gear 22 is mounted such that it can rotate freely via a bearing (not shown), such as a rolling bearing or a hydrodynamic bearing. Generally, the hydrodynamic bearing is supplied with a "low" pressure (typically less than 10 bar). Rotation of the bearing causes a lubricant wedge to build up pressure and separate the planetary gear from the bearing. Each bearing is mounted on one of the shafts of the planet carrier 23, and all shafts are positioned relative to each other using one or more structural frames of the planet carrier 23. Each planetary gear 22 meshes with the external teeth of the sun gear 21 and the internal teeth of the external ring gear 24. The internal teeth of the external ring gear 24 can be straight (parallel to the longitudinal axis), helical, or herringbone.

[0049] The number of shafts and bearings equals the number of planetary gears. Shafts and frames can be divided into multiple parts for operation, assembly, manufacturing, inspection, repair, or replacement.

[0050] For the same reasons mentioned above, the teeth of the reducer 20 can be divided into multiple propellers.

[0051] Still referencing Figure 4 The external gear ring 24 is divided into two gear ring halves 24a and 24b.

[0052] • The front gear ring half 24a consists of an edge 24aa and a radially extending front mounting flange half 24ab. The front propeller of the reducer's teeth is located on the edge 24aa. This front propeller meshes with the front propeller of the planetary gear 22, which in turn meshes with the front propeller of the sun gear 21.

[0053] • The rear gear ring half 24b consists of an edge 24ba and a radially extending rear mounting flange half 24bb. The rear propeller of the reducer's teeth is located on the edge. This rear propeller meshes with the rear propeller of the planetary gear 22, which meshes with the rear propeller of the sun gear 21.

[0054] Advantageously, but not limited to, the mounting flange half 24ab of the front gear ring half 24a and the mounting flange half 24bb of the rear gear ring half 24b form a first mounting flange 25 of the gear ring. The first mounting flange 25 is annular and extends radially outward. The gear ring (or both gear ring halves) 24 includes an axis of rotation, preferably coaxial with the axis of the turbine engine. The first attachment flange 25 extends radially from the radially outer surface 24c. The radially opposite inner radial surface 24d includes a propeller 32 (formed by the front and rear propellers) that meshes with the teeth of the planetary gear 22.

[0055] refer to Figure 5The ring gear carrier 26 connects the outer ring gear 24 to the stator of the turbine engine, for example, to the housing 16. The ring gear carrier 26 transmits torque from the reduction gear 20 to the stator of the turbine engine. Advantageously, but not limited to, the ring gear carrier 26 is annular and centered on the axis of the turbine engine. For this purpose, the ring gear carrier 26 includes a second attachment flange 27 at a first end 26a. In this example, the second attachment flange 27 extends radially inward (towards the longitudinal axis X).

[0056] Advantageously, but not limited to, the front mounting flange half 24ab and the rear mounting flange half 24bb each include orifices 31a and 31b, which pass through the walls of the front mounting flange half 24ab and the rear mounting flange half 24bb on both sides. Each orifice has an axis A parallel to the longitudinal axis X. The orifices 31a and 31b are regularly spaced around the longitudinal axis X and arranged coaxially with each other. For example, the number of orifices 31a and 31b is between 5 and 10.

[0057] The orifices 31a and 31b are configured such that the attachment member 40 (in) Figure 4 (Shown in dashed lines) can pass through. In other words, the axial orifices 31a and 31b are passed through by the attachment member 40. Advantageously, but not limited to, the attachment member 40 is a screw-nut type threaded element. Of course, the attachment member 40 can be any threaded element (e.g., an axial bolt) that mates with a clamping element or any other suitable component, so that it can be easily assembled and disassembled without damaging the component mounted with the attachment member 40.

[0058] like Figure 5 As shown, the second mounting flange 27 extends radially between the front mounting flange half 24ab and the rear mounting flange half 24bb. In other words, the mounting flange 27 is sandwiched between the two mounting flange halves 24aa and 24bb of the gear ring 24. This configuration avoids any stiffness difference between the front and rear gear ring halves.

[0059] The attachment flange 27 also has orifices 36 that axially pass through the walls of the attachment flange on both sides. Advantageously, but not limited to, in the installed configuration, the orifices 36 are coaxial with the orifices 31a and 31b of the front mounting flange half 24ab and the rear mounting flange half 24bb. The number of orifices 36 is the same as the number of orifices 31a and 31b.

[0060] When the attachment flange 27 is axially arranged between the front mounting flange half 24ab and the rear mounting flange half 24bb, the attachment member 40 passes through the orifice 36. The attachment member 40 is arranged to clamp the flange half 24ab, the flange half 24bb, and the attachment flange 27.

[0061] Advantageously, refer to Figure 4The attachment member 40 includes an axially extending screw 41 (shown in dashed lines) that applies an axial force to clamp the attachment flange. The number of attachment members 40 is the same as the number of orifices 31a, 31b, and 36. The head 41a (shown in dashed lines) of the screw 41 is pressed against the downstream surface of one flange half, and the nut 42 (shown in dashed lines) of flanges 24ab, 24bb, and 27 is mounted on the threaded shank of the screw 41 on one side of the other flange half, allowing the screw to clamp the nut 42 (shown in dashed lines) of flanges 24ab, 24bb, and 27.

[0062] exist Figure 5 Advantageously, but not limited to, the gear ring carrier 26 includes a connecting flange 43 at the second end 26b, which is configured to attach to an attachment member of the stator (such as housing 16) of the turbine engine. In this example, the flange 43 extends radially outward.

[0063] The gear ring holder 26 includes a gooseneck 28 configured to maintain a predetermined stiffness of the gear ring holder 26 at the flange halves and mounting flange 27. The gooseneck 28 extends from one end of the mounting flange 27 of the gear ring holder 26. The gooseneck 28 has a C-shaped axial cross-section, with its bottom 28a tangent to a radial plane PR located upstream of the front mounting flange half 24ab. In this way, the gooseneck 28 is larger than that of prior art goosenecks. This configuration ensures that the target stiffness of the gear ring holder 26 matches the sandwich assembly of flanges 24ab, 24bb, and 27. This shape also makes it easier to mount the retaining flange 27 between the two flange halves 24ab and 24bb of the gear ring 24, and also makes it easier to manufacture the gear ring holder 26 itself.

[0064] According to one example, the radius of curvature of the goose neck 28 (the axis of the goose neck 28 is perpendicular to the longitudinal axis X) is equal to 0.5 times the radial height (H1) of the front mounting flange half 24ab and the rear mounting flange half 24bb and / or the attachment flange 27.

[0065] Advantageously, the gear ring carrier 26 includes a flexible device 29 configured to, on the one hand, limit overloads in the turbine engine caused by displacement of certain components of the turbine engine and / or the reduction gear 20, and on the other hand, achieve a uniform and stable distribution of dynamic loads. In this example, the flexible device 29 includes at least one bellows 30. The gear ring carrier 26 includes a portion provided with a plurality of bellows 29.

[0066] Advantageously, but not limited to, the reducer 20 includes a lubricant discharge device 32, which is arranged at least in the front mounting flange half 24ab and the rear mounting flange half 24bb of the gear ring 24.

[0067] exist Figure 6In the example shown, the discharge device 32 includes discharge holes 33a and 33b, which are at least partially formed in the walls of the front flange half 24ab and the rear flange half 24bb of the gear ring 24. Advantageously, but not limited to, the discharge holes 33a and 33b extend radially. A plurality of discharge holes 33a and 33b are distributed around a longitudinal axis X. According to this example, the discharge holes open inside the flange (at the radially inner surface 24d of the gear ring 24) and on the annular periphery 38 of the flange 25 (flange halves 24ab and 24bb). The discharge holes may also open on the inner surfaces 35a and 35b of each flange half 24ab and 24bb. For example, the mounting flange 27 can be used to close the openings of the discharge holes, such that the lubricant also slides on the wall of the mounting flange 27 before being discharged from the mounting flange halves 24ab and 24bb.

[0068] Alternatively, discharge holes 33a, 33b are formed in the thickness of the wall of each flange half 24ab, 24bb.

[0069] According to an embodiment not shown, the mounting flange 27 may also include a discharge port to allow lubricant to be discharged to the outside of the reducer. The discharge port in the mounting flange 27 may have the same shape as the discharge ports in the flange halves 24ab, 24bb, or it may be formed within the thickness of the mounting flange 27. This increases the cross-sectional area of ​​the passage through which lubricant can pass in the reducer 20.

[0070] like Figure 6 As shown, the gear ring holder 26 may include through-holes 34 allowing lubricant to drain, the path of which is indicated by arrow L. Advantageously, the through-holes 34 radially penetrate the walls of the gear ring holder 26 on both sides. The through-holes are distributed around the longitudinal axis X, preferably evenly distributed. An advantageous feature is that the gear ring holder may include multiple rows of through-holes along the longitudinal axis X. The arrangement of these through-holes 34 also enables the elimination of lubricant stagnation areas within the turbine engine and reduces mass. The lubricant will fall into one or more bellows(s) 30 by gravity and be drawn through the through-holes 34.

[0071] Generally, lubricant enters the reducer 20 from the stator of the turbine engine via turbine stator blades (not shown) through various means. The turbine stator blades are divided into two parts, each containing the same number of planetary gears. The reducer includes injectors for lubricating the teeth and arms for lubricating the bearings of the planetary gears, these injectors and arms being connected to the turbine stator blades. Lubricant is supplied to the injectors and flows out from one end of the injectors to lubricate the teeth, and is also supplied to the arms to circulate among the various components of the reducer 20. The lubricant then exits through discharge holes 33a, 33b and through holes 34, which are located at the interface with the mounting flange halves 24ab, 4bb.

[0072] Advantageously, but not limited to, lubricants include oils.

Claims

1. A reduction gear (20) for an aircraft turbine engine (1), the reduction gear having a longitudinal axis X, the reduction gear comprising a sun pinion (21), a planetary pinion (22), an external gear ring (24), and a gear ring carrier (26), the gear ring carrier being attached to the external gear ring (24), the planetary pinion (22) meshing with the sun pinion (21) on one side and with the external gear ring (24) on the other side, the external gear ring (24) being formed by two gear ring halves (24a, 24b), each of the two gear ring halves having a radially outwardly extending front mounting flange half (24ab) and a rear mounting flange half (24bb), the two gear ring halves being attached to an attachment flange (27) of the gear ring carrier (26) by an attachment member (40), the gear ring carrier including a gooseneck (28) capable of centering the gear ring (24), characterized in that, The attachment flange (27) extends radially between the front mounting flange half (24ab) and the rear mounting flange half (24bb), and the gooseneck (28) has a C-shaped axial section, the bottom (28a) of the gooseneck being tangent to a radial plane (PR) located upstream of the front mounting flange half (24ab).

2. The reducer (20) according to claim 1, characterized in that, The radius of curvature of the goose neck (28) is equal to 0.5 times the radial height (H1) of the front mounting flange half and the rear mounting flange half (24ab, 24bb).

3. The reducer (20) according to any one of the preceding claims, characterized in that, The reducer includes a lubricant discharge device (32), which is arranged at least in the front mounting flange half and the rear mounting flange half.

4. The reducer (20) according to claim 3, characterized in that, The discharge device (32) includes discharge holes (33a, 33b) that are at least partially formed in the walls of the front flange half and the rear flange half (24ab, 24bb) and extend radially.

5. The reducer (20) according to any one of the preceding claims, characterized in that, The front mounting flange half (24ab), the rear mounting flange half (24bb), and the attachment flange (27) of the gear ring holder (26) each include axial attachment orifices (31a, 31b, 36), the attachment member (40) passes through the axial attachment orifices, and the axial attachment orifices (31a, 31b, 36) are arranged circumferentially around the longitudinal axis X.

6. The reducer (20) according to the preceding claim, characterized in that, The attachment member (40) includes an axial screw (41) or axial bolt passing through the orifice (31a, 31b, 36).

7. The reducer (20) according to any one of the preceding claims, characterized in that, The gear ring holder (26) includes a flexible device (29), such as at least one bellows (30).

8. The reducer (20) according to any one of the preceding claims, characterized in that, The gear ring holder (26) includes a through hole (34) that radially passes through both sides of the wall of the gear ring holder (26).

9. The reducer (20) according to any one of the preceding claims, characterized in that, The gear ring (24) is connected to the housing of the turbine engine and cannot rotate relative to the longitudinal axis.

10. The reducer (20) according to any one of claims 1 to 8, characterized in that, The gear ring (24) is connected to the shaft of the turbine engine and is capable of rotating about the longitudinal axis.

11. A turbine engine (1), particularly a turbine engine for an aircraft, the turbine engine having a longitudinal axis X, and including a reduction gear (20) according to any one of the preceding claims.

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