Modularity of aircraft turbomachines

Abstract

An aircraft turbomachine (10) having a longitudinal axis (A) and comprising a high-pressure body, called HP body, a low-pressure body, called BP body, a fan (48) and a reduction gear (36) having a planetary gear train; the turbomachine is characterized in that the BP body comprises three modules: a first module (22) comprising a BP turbine (24) and a BP shaft (26); a second module (28) comprising a BP compressor (30) and a journal (68) fixed to a rotor of the BP compressor; and a third module (32) comprising an input shaft (34) of the reduction gear (36), the input shaft comprising an upstream end for coupling to a sun gear (38) of the reduction gear and a downstream end comprising a first spline (74) oriented parallel to said axis and configured to engage in a second complementary spline (76) of said second module (28).

Description

Technical Field

[0001] This invention relates to a modular solution for aircraft turbines. Background Technology

[0002] Prior art specifically includes documents WO-A1-2015 / 075345, US-A1-3,631,688, FR-A1-2,975,149, US-A-3,958,887 and US-A-3,469,868.

[0003] Aircraft turbines are typically constructed as modular components, each of which may have fixed and moving parts. A module is defined as a subgroup of an engine, which has geometric features at its interface with adjacent modules that are precise enough to allow the subgroup to be transported independently and, when it includes rotating parts, to be individually balanced. The modular composition enables the construction of a complete engine that minimizes the balancing and fitting operations of the interface components.

[0004] Modular design is a key factor in turbine maintenance. In practice, components must be easily accessible during intervention without requiring the disassembly of large portions of the engine. In practice, we attempt to achieve this by breaking it down into multiple main modules. For example, for a turbine with an upstream fan (the terms "upstream" and "downstream" should be understood in relation to the flow of gas within the turbine), we are seeking to divide it into three modules: a first main module for the front section, including the fan and BP compressor; a second main module for the section including the HP body; and a third main module for the rear section of the engine, including the BP turbine and BP shaft. Therefore, it should be understood that the BP body is divided into two modules.

[0005] The two modules of the BP body are fixed to each other by nuts that extend around the turbine axis and are used to axially clamp the fan shaft to the BP shaft.

[0006] During maintenance operations, the nut must be loosened by a tool inserted into the turbine along the turbine's longitudinal axis, thereby penetrating the interior of the BP shaft and / or fan shaft.

[0007] This type of maintenance is particularly difficult for turbines with reduction gears in the front or upstream section. The problem in this case lies in the accessibility of the nut. The reduction gear is located upstream of the nut and must be partially removed to access it. Furthermore, complex tools must be used to access the nut, which carries the risk of improper handling and engine damage.

[0008] In this configuration, the modularity of the first main module is lost. Furthermore, the second and third main modules must be disassembled independently.

[0009] However, when the first module includes a reduction gear, modularity of the first module is important. The reduction gear is housed in a lubrication enclosure, which should preferably remain closed during maintenance to prevent oil leakage. To avoid disassembling the enclosure, there is a tendency to increase the inner diameter of the reduction gear, making it larger than the diameter of the nut, thus allowing the nut to be removed from inside the reduction gear. However, this solution is detrimental to the size of the reduction gear and the overall performance of the turbine.

[0010] To improve turbine propulsion efficiency, turbines tend to increase the bypass ratio, which typically translates to an increase in fan size (diameter and axial dimensions). This makes the nut near the BP shaft even more complex, as the tools required to access the nut become longer.

[0011] In addition, some turbines (such as turbines with unducted single fan (USF)) are particularly long, and the modules of HP and BP bodies have very small inner diameters, making it difficult or impossible for tools to access the nuts.

[0012] This invention provides solutions to at least some of the problems mentioned above, which simplify the modularization of aircraft turbines. Summary of the Invention

[0013] According to a first aspect, the present invention relates to a shaft assembly for an aircraft turbine, the shaft assembly comprising:

[0014] - A first shaft, comprising an external spline oriented parallel to the axis of rotation of the shaft.

[0015] - A second shaft, comprising an internal spline complementary to the external spline, axially engaging with the first shaft, and the shafts rotating as a whole through the engagement of their splines.

[0016] - A system for axially locking shafts relative to each other.

[0017] The system is characterized in that it includes screws radially oriented relative to the axis, each screw being screwed into a first hole of one of the shafts and including a free end capable of engaging a second hole of the other shaft. Each screw can be moved between a first radial position and a second radial position, in which the free end of the screw engages in the second hole and ensures axial locking of the shaft, and in the second radial position, the free end of the screw disengages from the second hole and ensures axial unlocking of the shaft.

[0018] The shaft assembly according to the invention is particularly suitable for facilitating the modularization of aircraft turbines and can be used, for example, in the interface between two modules of an aircraft, and more specifically, in the interface between two shafts of these modules.

[0019] The connection between the two shafts is achieved via splines. The splines extend parallel to each other and engage with the second shaft through a simple axial translation of the first shaft.

[0020] There are two types of spline couplings. In the first type, the splines slide freely axially within each other. A primary disadvantage of this type is that the splines require lubrication, necessitating the placement of an oil spray nozzle nearby. In turbines with reduction gears, the splines can be housed within the gearbox enclosure for lubrication; however, disengagement of the splines during maintenance operations will require opening the enclosure.

[0021] The second type of spline coupling is a coupling in which the splines are axially locked together, and this is the technology used in this invention. The advantage is that the splines do not require lubrication. However, an axial locking system must be provided for the shafts so that the splines are axially locked together.

[0022] According to the invention, this locking is provided by radial screws. In other words, the locking screws of the shaft do not extend parallel to the axis, but rather extend radially relative to the axis. The screws can be evenly distributed around the axis, and the number of screws is specifically adjusted according to the diameter of the shaft and the maximum torque to be transmitted between these shafts.

[0023] The group according to the invention may include one or more of the following features, which may be used individually or in combination with each other:

[0024] - The first position is the radially outer position, and the second position is the radially inner position;

[0025] - Each screw in the screw includes a radially inner end and a radially outer free end, the radially inner end carrying a head support, and the radially outer free end including a recessed cavity configured to receive a tool for tightening / loosening the screw;

[0026] - A centering ring is fixed in each of the second holes and includes an inner orifice having a truncated conical section configured to engage with the free end of the screw to center the screw in the second hole; the advantage of providing a centering ring in each second hole is that the ring can be replaced in case of wear by limiting the impact on the shaft;

[0027] - Each ring is pressed into the corresponding second hole;

[0028] - A sleeve is installed in each of the first holes in the first hole and includes an internal thread for tightening the corresponding screw; the advantage of providing a threaded sleeve in each first hole is that the sleeve can be replaced in case of wear and limits the impact on the shaft;

[0029] - Each sleeve includes an outer annular collar for support on the corresponding shaft;

[0030] - The retaining housing is mounted inside the first shaft and includes a first cylindrical edge that extends at least partially opposite the first hole and the second hole and is configured to radially retain the screw when the screw is in the respective second position of the screw;

[0031] - Each sleeve's collar is radially positioned between the second cylindrical edge of the shaft and the housing; and

[0032] The housing includes an outer cylindrical centering surface configured to mate with an inner cylindrical surface of a first shaft. The inner cylindrical surface includes an annular groove for mounting an annular ring that axially holds the housing relative to the first shaft.

[0033] The present invention also relates to an aircraft turbine comprising at least one group as described above.

[0034] Advantageously, the assembly is surrounded by at least one stator housing, the at least one stator housing including at least one radial hole configured to allow a tool for tightening / loosening the screw to pass through.

[0035] According to another aspect, the present invention relates to an aircraft turbine having a longitudinal axis and comprising:

[0036] - High-pressure body, referred to as HP, includes an HP shaft for connecting the HP compressor rotor to the HP turbine rotor, the HP shaft extending along the axis described above.

[0037] - The low-pressure body, referred to as BP, includes a BP shaft for connecting the BP compressor rotor to the BP turbine rotor. The BP shaft extends along the axis and is located inside the HP shaft.

[0038] - The fan, which is connected to the fan shaft, and

[0039] - Planetary speed reducer, which connects the BP shaft to the fan shaft.

[0040] Its characteristic is that the low-voltage main body comprises three modules:

[0041] - A first module, comprising a BP turbine and a BP shaft, the BP shaft including a downstream end connected to the rotor of the BP turbine.

[0042] - A second module, comprising a BP compressor and a journal fixed to the rotor of the BP compressor, the journal being configured to be rotatably coupled to the upstream end of the BP shaft and axially secured to that end by tightening a nut onto the threads on the shaft, and

[0043] - A third module includes an input shaft for a speed reduction device, the input shaft having an upstream end and a downstream end, the upstream end of the input shaft being connected to the sun gear of the speed reduction device, the downstream end of the input shaft including a first spline oriented parallel to the axis and configured to engage in a complementary second spline of the second module, a radially oriented screw being carried by one of the second and third modules and intended to engage in the other of the second and third modules to axially lock the first and second splines in each other.

[0044] Therefore, the BP turbine body is divided into three modules, instead of the two modules found in most previous turbines. The first module is a conventional module, which includes the BP turbine and the BP shaft. The BP shaft extends along the turbine's axis, and its downstream end is connected to the rotor of the BP turbine.

[0045] The second module includes a BP compressor, the rotor of which is typically connected to a journal. As in the prior art, this journal engages with the BP shaft and is secured to the BP shaft by a nut that is axially tightened from upstream. The second module is splined to a third module, which includes the input shaft of a reduction gear.

[0046] These splines are axially locked by radial screws. When the screws are in the loosened position, it should be understood that the third module can be disassembled and removed from the second module.

[0047] Before approaching the second module from the first module to loosen the nut, the third module, which has a reduction gear, can be disassembled and removed from the turbine. The advantage of this is that the inner diameter of the reduction gear can be smaller than the diameter of the nut, and the nut is no longer removed from inside the reduction gear. The locking screws of the second and third modules are radially oriented, so they can be loosened with a tool oriented in the same direction, which will not be obstructed by the reduction gear.

[0048] The turbine according to the invention may include one or more of the following features, which may be adopted independently of each other or in combination with each other:

[0049] - The fan is ductless;

[0050] - The speed reduction device is located in the lubrication enclosure, and the first spline and the second spline are located outside the enclosure;

[0051] - The first spline and the second spline are axially located between two annular seals of the enclosure, which are installed between the input shaft and the annular cover of the enclosure, which is mounted around the input shaft;

[0052] -The first seal among these seals, located upstream of the first spline and the second spline, is a segmental radial seal; the second segmental seal among these segmental seals, located downstream of the first spline and the second spline, is a labyrinth seal.

[0053] - One of these seals is axially positioned between the first and second splines on one side and the screw on the other side;

[0054] - The second module includes an upstream shaft section and a downstream shaft section. The upstream shaft section includes the second spline and a mounting hole for the screw. The downstream shaft section is coupled to or connected to the journal. The shaft section includes an annular flange, which is secured together by screws oriented parallel to the axis.

[0055] - The upstream shaft section includes a first radial annular wall, the outer periphery of which is connected to a first flange in a flange; the downstream shaft section includes a second radial annular wall, the outer periphery of which is connected to a second flange in a flange; the first and second annular walls extend opposite to each other and impart bending deformation capability to the second module during operation; this type of connection provides flexibility to the module and is commonly referred to as a "flexible coupling"; and

[0056] - The turbine includes a stator housing that surrounds the BP body and the HP body, and the stator housing includes at least one radial hole configured to allow a tool for tightening / loosening the radial screw to pass through.

[0057] The present invention also relates to a method for disassembling a turbine as described above, characterized in that the method includes the following steps:

[0058] - Loosen the radial screws to axially unlock the first and second splines.

[0059] -Withdraw the third module from the second module.

[0060] - Loosen the nuts from inside the fan and speed reducer, and

[0061] - Remove the second module from the first module.

[0062] Advantageously, the radial screws are loosened by at least one loosening tool, which is inserted through the hole in the housing or each hole. Attached Figure Description

[0063] Other features and advantages of the invention will become apparent from the following detailed description, which, for understanding, is illustrated in the accompanying drawings:

[0064] [ Figure 1 ] Figure 1 This is a schematic half-view of the axial section of an aircraft turbine;

[0065] [ Figure 2 ] Figure 2 This is a schematic perspective view of the axial cross section of the shaft assembly in one aspect of the present invention;

[0066] [ Figure 3 ] Figure 3 yes Figure 2 A schematic cross-section of the group shown;

[0067] [ Figure 4 ] Figure 4 It is used for axial locking. Figure 2 A schematic perspective view of the spline system of the group, showing the screw in the unlocked position;

[0068] [ Figure 5 ] Figure 5 This is a schematic cross-section of an axial locking system, with the screw in the unlocked position;

[0069] [ Figure 6 ] Figure 6 This is a schematic cross-section of an axial locking system, with the screw in the locked position;

[0070] [ Figure 7 ] Figure 7 yes Figure 6 A magnified view of a portion;

[0071] [ Figure 8 ] Figure 8 Is with Figure 1 A similar view is shown, illustrating the first step of the method for disassembling an aircraft turbine according to the present invention;

[0072] [ Figure 9 ] Figure 9 yes Figure 8 A magnified view of a portion; and

[0073] [ Figures 10a-10c ] Figures 10a to 10c Is with Figure 1 A similar view is shown, along with other steps in the disassembly process. Detailed Implementation

[0074] First refer to Figure 1 , Figure 1 An aircraft turbine is shown, in this case an unducted single-fan (USF) turbine 10, although aspects of the invention are not limited to this particular type of turbine.

[0075] Turbine 10 is modular and comprises multiple modules assembled together. Reference numeral A refers to the longitudinal axis of turbine 10, which is typically the axis of rotation of the turbine rotor.

[0076] The first module 12 is a high-pressure or HP module and includes an HP compressor 14 and an HP turbine 18. The rotor of the HP compressor 14 is connected to the rotor of the HP turbine 18 via an HP shaft 16. The HP module 12 also includes an annular combustion chamber 20, which is axially located between the HP compressor 14 and the HP turbine 18.

[0077] The low-pressure or BP main body of turbine 10 is divided into three modules:

[0078] - First module 22, which includes a BP turbine 24 and a BP shaft 26, the BP shaft including a downstream end connected to the rotor of the BP turbine.

[0079] - Second module 28, which includes BP compressor 30.

[0080] - and a third module 32, which includes the input shaft 34 of the turbine's reduction gear 36.

[0081] In practice, the turbine 10 is equipped with a planetary gear reducer 36, which typically includes: a sun gear 38 centered on axis A; a ring gear 40 extending around the sun gear 38; and planetary gears arranged between the sun gear and the ring gear, meshing with both gears and carried by a planet carrier 42. In this configuration, the ring gear 40 is stationary and fixed to the turbine stator, which in this case is the inlet housing 44. The sun gear 38 is rotatably movable and connected to the input shaft 34, and the planet carrier 42 is also rotatably movable and connected to the shaft 46 of the fan 48. Therefore, the fan 48 is driven to rotate by the input shaft 34 via the gear reducer 36.

[0082] The reduction gear 36 is located within a lubrication enclosure 50, which extends about axis A and is therefore generally annular. The enclosure 50 is defined at its inner periphery by a fan shaft 46 and an inlet shaft 34. At its outer periphery, the enclosure 50 is defined by an inlet housing 44, which extends around the reduction gear 36. At its upstream end, the enclosure 50 is defined by an annular support 52 for bearings 54 and 56. This support 52 has an outer periphery attached to the inlet housing 44 and an inner periphery holding the bearing rings of the roller bearings 54 and 56, the inner rings of which are attached to the fan shaft 46. Finally, at its downstream end, the enclosure 50 is closed by an annular cap 58, carried by the inlet housing 44, with its inner periphery sealingly surrounding the inlet shaft 34.

[0083] The intermediate housing 60 is located between the BP compressor 30 and the HP compressor 14, the turbine housing 62 is located between the HP turbine 18 and the BP turbine 24, and the exhaust housing 64 is located downstream of the BP turbine 24.

[0084] The BP compressor 28 and HP module 12 are surrounded by an annular housing 66, the upstream end of which includes an annular flange 66a for securing the annular flange 44a of the inlet housing 44, and the downstream end of which includes an annular flange 66b for securing the annular flange 64a of the exhaust housing 64.

[0085] In addition to the BP compressor 30, the second module 28 also includes a journal 68 which is rotatably fixed to the rotor of the BP compressor and is configured to be rotatably coupled to the upstream end of the BP shaft 26 and axially fixed to the end by screwing a nut 70 onto the thread of the BP shaft 26.

[0086] In the example shown, journal 68 is axially engaged from upstream to the upstream end of BP shaft 26. Nut 70 is axially engaged from upstream to the upstream end of shaft 26 and is tightened until the nut axially clamps journal 68 against the annular shoulder or similar structure of shaft 26.

[0087] Although it is illustrative, from Figure 1 It can be seen that the diameter of nut 70 is larger than the inner diameter of input shaft 34. This means that input shaft 34 must be disassembled and removed in order to remove nut 70.

[0088] The second module 28 also includes a shaft 72, which is divided into two segments 72a and 72b, located upstream and downstream respectively. The shaft segments 72a and 72b are fixed to each other by clamping.

[0089] The upstream segment 72a is connected to the input shaft 34 and includes a radially outer fastening flange 72aa at its downstream end. The flange 72aa is located at the outer periphery of the radial annular wall 72ab at the downstream end of the segment 72a.

[0090] The downstream section 72b is rotatably fixed to the journal 68 and the rotor of the BP compressor 30, and includes a radially outer fastening flange 72ba at the upstream end of the downstream section. The flange 72ba is located at the outer periphery of the radial annular wall 72bb at the upstream end of the section 72b.

[0091] Flanges 72aa and 72ba are applied abutting each other axially and include axial screw mounting holes (not visible) for fastening the flanges together. This configuration of flanges 72aa and 72ba and radial walls 72ab and 72bb enables a flexible connection. This means the shaft can withstand misalignment between the upstream and downstream portions, which is particularly advantageous in the case of relatively long engines.

[0092] The present invention provides a solution that facilitates the modularity of turbine 10 by means of specific devices for connecting the shaft 72 of modules 28, 32, and in particular the second module 28, to the input shaft 34 of the third module 32.

[0093] Figures 2 to 7 An embodiment of the device is shown, in which the previously described elements are indicated by the same reference numerals.

[0094] The input shaft 34 of module 32 is connected to the shaft 72 of module 28 via spline couplings 74 and 76, and more specifically, to shaft segment 72a. The input shaft 34 includes an internal spline 74 adjacent to its downstream end, the internal spline being oriented parallel to axis A and configured to engage with the complementary external spline 76 of shaft segment 72a.

[0095] Spline couplings 74 and 76 are axially locking type spline couplings, and this locking is ensured by screws 78, which are oriented radially relative to axis A.

[0096] Preferably, the screws 78 are evenly distributed around axis A. The number of screws is, for example, between 6 and 12.

[0097] Each of the screws 78 is carried by a bearing in one of the shafts 34, 72 and screwed into that one shaft, and each of the screws is intended to engage with the other shaft to axially lock the splines 74, 76 into each other. It should be understood that each screw 78 is radially movable by screwing it from a first radially locked position to a second radially unlocked position, and vice versa.

[0098] In the example shown, such as Figures 4 to 7 As can be clearly seen, each screw 78 is screwed into a hole 80 in the shaft section 72a and includes a free end adapted to engage in a hole 82 in the shaft 34. Each screw 78 is movable by being screwed from a first radial position to a second radial position, the first radial position being a radially outer tightened position of the screw and the second radial position being a radially inner loosened position.

[0099] Each screw 78 includes a threaded body that is elongated radially relative to axis A and has a longitudinal (radially outer) free end and an opposing longitudinal (radially inner) end connected to a head 84. The body of each screw 78 is intended to be screwed into one of the holes in the bore 80, the head 84 of each screw is intended to rest against the shaft section 72a in a first fastened position, and the free end of each screw is intended to engage in one of the holes 82 of the shaft 34 in this first position to axially lock the splines 74, 76 and the shafts 34, 72.

[0100] Each screw 78 is rotated and tightened by a tool, which must also be radially or quasi-radially oriented relative to axis A. According to one aspect of the invention, the tightening and loosening of each screw is performed radially from the outside of the turbine, not the inside. Therefore, the tool must be able to access and engage the radially outer end of each screw 78. Thus, the tool is not intended to engage with the head 84 of each screw 78, but rather with the free end of the screw, which includes, for example, a recessed cavity 81, such as... Figure 4 and Figure 7 It is shown schematically in the diagram.

[0101] The recess 81 may have a polygonal or, for example, hexagonal cross-sectional shape to receive a hexagonal fitting, such as a tool. Alternatively, the recess may be Type.

[0102] exist Figure 1 , Figure 2 and Figure 9 The diagram schematically illustrates a tool 83 for loosening screw 78 and tightening screw 78. The tool 83 has an elongated shape and is engaged through one or more holes 85 in the turbine 10. These holes 85 may be located on stator elements of the turbine (such as intermediate housing 44 or housing 66). These holes 85 are, for example, endoscopic holes, i.e., holes typically used for endoscopic inspection of turbines. Of course, these holes must be aligned with each other and, as far as possible, with the shaft of screw 78. Rotation of shaft 34 allows screw 78 to be approached one by one through holes 85.

[0103] In the example shown, a ring 86 is secured in each hole 82 of the shaft 34. The ring 86 includes an inner aperture having a truncated conical section 86a configured to mate with the free end of a screw 78 to center the screw within the hole 82. The section 86a flares radially inward. The ring 86 is pressed into the hole 82, and its radially outer end includes a circumferential edge 86b designed to plastically deform and press against the inner edge 82a of the hole 82 (see, for example, [reference needed]). Figure 5 Therefore, it should be understood that the ring 86 is inserted radially into the hole 82 from the inside and then pressed into the hole by the deformation of the edge 86b of the ring.

[0104] Furthermore, in the example shown, each screw 78 is not screwed directly into one of the holes in the bore 80, but rather into a sleeve 88 mounted in that hole. The sleeve 88 has internal threads 88a for tightening the screws 78, and also includes an annular collar 88b at its radially inner end, which is used for support on a boss of the shaft 72 (see, for example). Figure 5 ).

[0105] The sleeve 88 is retractable into the bore 80 and includes an outer cylindrical surface that clamps into the inner cylindrical surface of the bore 80. The sleeve 88 engages radially into the bore 80 from the inside until the collar 88b rests against the boss of the shaft 72. If the threads of the sleeve 88 and the collar 86 wear, the sleeve and collar can be replaced without replacing the entire shaft.

[0106] Advantageously, the retaining housing 90 is mounted inside the shaft 72 and has the function of retaining the screw 78, thereby capturing the screw when it is in the loosened position.

[0107] The housing 90 is annular in shape and extends about axis A. The housing includes a first cylindrical edge 92 that faces downstream and extends at least partially opposite holes 80, 82, and is configured to radially retain the screw when the screw 78 is in the loosened position, as... Figure 4 and Figure 5 As shown.

[0108] Preferably, the housing 90 includes an outer cylindrical centering surface 90a configured to mate with an inner cylindrical surface of the shaft 72 for centering the housing during installation. The inner cylindrical surface of the shaft 72 may include an annular groove 94 for mounting an annular ring (not shown) for axially holding the housing 90 against, for example, the aforementioned boss of the shaft 72.

[0109] The housing 90 also includes a second cylindrical edge 92 that faces downstream and extends partially around the boss. A collar 88b of the sleeve 88 is radially positioned between the boss and the edge 96, which provides radial retention of the sleeve in the bore 80 and also keeps the sleeve either captured or radially stationary.

[0110] Figure 4 and Figure 5 The screw 78 is shown in the loosened position to unlock shafts 34 and 72. It can be seen that the head 84 of the screw 78 rests radially against the edge 92 of the housing 90, and the free end of the screw is at a radial distance from the hole 82. Therefore, the screw 78 does not interfere with the movement of shafts 34 and 72 relative to each other, nor with the axial disengagement of splines 74 from each other.

[0111] Figure 6 and Figure 7 The screw 78 is shown in the tightened position to axially lock the shafts 34 and 72. It can be seen that the head 84 of the screw 78 is at a radial distance from the edge 92 of the housing 90, and the free end of the screw engages in the ring 86 of the hole 82. The screw 78 prevents the shafts 34 and 72 from moving relative to each other and prevents the splines 74 from axially disengaging from each other.

[0112] Regarding splines 74 and 76 Figure 2 and Figure 3 Specifically, the spline is shown to be located outside the lubrication enclosure 50 of the reduction gear 36, or more precisely, downstream of the lubrication enclosure of the reduction gear.

[0113] In the example shown, splines 74 and 76 are axially located between the two annular seals 98 and 100 of the enclosure 50, i.e., the two seals are located at the downstream end of the enclosure 50 and are installed between the cover 58 and the input shaft 34.

[0114] The upstream seal 98 of splines 74 and 76 is a partial radial seal, and the downstream seal 100 of splines is a labyrinth seal. Screw 78 is located downstream of splines 74 and 76 and seals 98 and 100, and seal 100 is axially positioned between the splines and screw 78.

[0115] from Figure 2 and Figure 3 It can also be seen that the diameters of seals 98 and 100, splines 74 and 76, and screw 78 are relatively close to each other.

[0116] Now refer to Figures 8 to 10c , Figures 8 to 10c A disassembly is shown. Figure 1 The turbine 10 steps. It should be understood that the turbine can be assembled or reassembled by repeating these operations in reverse order.

[0117] Figure 8 Similar to Figure 1 , Figure 9 This is an enlarged view showing some references to the shaft assembly described above according to the invention.

[0118] The first step of the method involves inserting a tool 83 through the hole 85 of the turbine 10, and then loosening the screws 78 one by one to bring them from a tightened position to a loosened position. This can be achieved by rotating the shafts 34, 72 after each loosening so that the next screw to be loosened aligns with the hole 85, either by engaging a single tool in a single hole 85 or in a single series of aligned holes 85. Alternatively, in the case where there are as many holes 85 as screws 78 or a series of holes 85, the same tool 83 can be inserted sequentially into each of these holes or the series of holes.

[0119] Then, screw 78 is in the loosened position, allowing splines 74, 76 and shafts 34, 72 to move freely axially relative to or against each other. This means that the third module 32 can be separated from the second module 28. For this, it may be necessary to disengage flanges 44a, 66a from each other. After this separation, the entire upstream section of the turbine (including module 28, as well as the reduction gear 36, fan 48, and intermediate housing 44) can be accessed from... Figure 10a The remainder of the turbine shown is removed. Therefore, it should be understood that the containment 50 remains closed, which limits the risk of oil leakage.

[0120] Another step of the method involves loosening the nut 70 that holds the two modules 28, 22 together. The nut is then loosened and removed from the upstream side. This gives the following... Figure 10b The situation is shown.

[0121] The next step of the method is to disengage flanges 66b and 64a from each other and axially remove exhaust housing 64 from the downstream side. Figure 10c Then, the first module can be removed by moving the first module 22 axially downstream from the second module 28, the HP module 12, the compressor housing 60, and the turbine housing 62.

[0122] The various modules of turbine 10 are disconnected from each other and can be maintained by reassembling the turbine.

Claims

1. A turbine (10) for an aircraft, the turbine having a longitudinal axis (A), and the turbine comprising: - High-pressure body, the high pressure being referred to as HP, the high-pressure body including an HP shaft (16) for connecting an HP compressor rotor (14) to an HP turbine rotor (18), the HP shaft extending along the longitudinal axis. - Low-pressure body, the low pressure being referred to as BP, the low-pressure body including a BP shaft (26) for connecting the BP compressor rotor to the BP turbine rotor, the BP shaft extending along the longitudinal axis and inside the HP shaft. - Fan (48), the fan being connected to fan shaft (46), and - Planetary speed reducer (36), which connects the BP shaft (26) to the fan shaft (46). The low-voltage main body is characterized by comprising three modules: - A first module (22), comprising a BP turbine and a BP shaft (26), the BP shaft including a downstream end connected to the rotor of the BP turbine. - Second module (28), the second module including a BP compressor and a journal (68) fixed to the rotor of the BP compressor, the journal being configured to be rotatably coupled to the upstream end of the BP shaft (26) and axially fixed to that end by tightening a nut (70) onto the threads on the shaft, and - A third module (32) includes an input shaft (34) of the planetary reducer (36), the input shaft having an upstream end and a downstream end, the upstream end of the input shaft being connected to the sun gear (38) of the planetary reducer, the downstream end of the input shaft including a first spline (74) oriented parallel to the longitudinal axis and configured to engage in a complementary second spline (76) of the second module (28), a radial screw (78) being carried by one of the second and third modules and intended to engage in the other of the second and third modules to axially lock the first spline and the second spline into each other.

2. The turbine (10) according to claim 1, wherein, The fan (48) is ductless.

3. The turbine (10) according to claim 1 or 2, wherein, The planetary deceleration device (36) is located in the lubricating enclosure (50), and the first spline (74) and the second spline (76) are located outside the enclosure.

4. The turbine (10) according to claim 3, wherein, The first spline (74) and the second spline (76) are axially located between two annular seals (98, 100) of the enclosure (50), the two annular seals being installed between the input shaft (34) and the annular cover (58) of the enclosure, the annular cover being installed around the input shaft.

5. The turbine (10) according to claim 4, wherein, The first seal (98) located upstream of the first spline (74) and the second spline (76) is a segmental radial seal, and the second segmental seal (100) located downstream of the first spline and the second spline is a labyrinth seal.

6. The turbine (10) according to claim 4 or 5, wherein, One of these seals (100) is axially located between the first spline (74) and the second spline (76) on one side and the radial screw (78) on the other side.

7. The turbine (10) according to claim 1 or 2, wherein, The second module (28) includes an upstream shaft section (72a) and a downstream shaft section (72b). The upstream shaft section includes the second spline (76) and a hole (80) for mounting the radial screw (78). The downstream shaft section is coupled to or connected to the journal (68). The shaft sections (72a, 72b) include annular flanges (72aa, 72ba) that are secured together by screws oriented parallel to the longitudinal axis.

8. The turbine (10) according to claim 7, wherein, The upstream shaft section (72a) includes a first radial annular wall (72ab), the outer periphery of which is connected to a first flange (72aa) in the annular flange, and the downstream shaft section (72b) includes a second radial annular wall (72bb), the outer periphery of which is connected to a second flange (72ba) in the annular flange, the first radial annular wall and the second radial annular wall extending relative to each other and giving the second module (28) the ability to bend and deform in operation.

9. The turbine (10) according to claim 1 or 2, wherein, The turbine includes a stator housing (44, 66) surrounding the low-pressure body and the high-pressure body, and the stator housing includes at least one radial hole (85) configured to allow a tool (83) for tightening / loosening the radial screw (78) to pass through.

10. A method for disassembling a turbine (10) according to any one of claims 1 to 9, characterized in that, The method includes the following steps: - Loosen the radial screw (78) to axially unlock the first spline (74) and the second spline (76). - Remove the third module (32) from the second module (28). - Loosen the nut (70) from inside the fan (48) and the speed reduction device (36), and - Remove the second module (28) from the first module (22).

11. The method according to claim 10, wherein, The radial screws (78) are loosened by at least one loosening tool (83), which is inserted through each radial hole (85) in the stator housing (44, 66) surrounding the low-pressure body and the high-pressure body of the turbine.

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