Method for assembling a gear train

Abstract

The invention provides a method for assembling an epicyclic gear train or a planetary gear train from at least one pivot and a planetary gear carrier, the planetary gear carrier comprising one or more holes, each hole being intended to receive a pivot, the method comprising the steps of: a) measuring the position of the real axis of each of the at least one pivot and the one or more holes of the carrier; b) dividing each of the pivots into n angular sectors i extending around the theoretical axis of the pivot 1 ...i q ...i n , and divides each of the holes of the bracket into k angular sectors j extending around the theoretical axis of the hole 1 ... l ... k ; c) For each pivot, define the vector #imgabs0# from the theoretical axis to the real axis and identify the angular sector i that includes the vector ‑#imgabs1# q d) For each hole, define the vector #imgabs2# from the theoretical axis to the real axis and identify the angular sector j that includes the vector #imgabs3# l e) For each hole of the bracket, install the pivot so that for each component, the angular sector j is identified l and i q are superimposed.

Description

Technical Field

[0001] The invention relates to a method for assembling an epicyclic or planetary gear train for equipping a turbine engine, such as a turbojet engine or an aircraft turboprop engine. Background Art

[0002] A turbine engine may include a gear train that connects its turbine shaft to one or more output elements, such as fan impellers. This type of gear train includes an inner planetary gear (also called a sun gear) driven by an input shaft, such as a turbine shaft; an outer planetary gear (also called a ring gear) that is coaxial with the sun gear, the planetary gears meshing with both the sun gear and the ring gear; and a planetary gear carrier on which the planetary gears are rotatably mounted. The planetary gears are movably and rotatably mounted on a pivot that is inserted into a hole in the carrier.

[0003] In a specific configuration, a gear train can reduce the speed between the input and output of the gear train. The variation of the reduction ratio of such a gear train is obtained by varying the number of teeth of the sun gear, the planetary gears and the ring gear and by the structure of the gearbox, i.e. an epicyclic or planetary gearbox structure. These two types of gear trains differ from each other in that in the so-called epicyclic gear trains, the ring is fixed and the carrier is free to rotate. In contrast, in the so-called planetary gear trains, the planet gear carrier is fixed and the outer gear or the ring gear is free to rotate.

[0004] In the case of these two types of gear trains, there is a difference in the power transmitted through the planetary gears of the carrier. This difference may cause excessive mechanical stress to be applied to some of the planetary gears.

[0005] According to the ANSI / AGMA 6123-B06 standard established by the American Gear Manufacturers Association (AGMA), under actual operating conditions, the overload of each planet gear of an epicyclic gear train or a planetary gear train must be approximately 12%.

[0006] One of the reasons for this difference is the relative positioning error of the planetary gears, in particular the relative tangential positioning error of the planetary gears relative to each other about the carrier axis. In addition, the misalignment of the teeth of the planetary gears with the teeth of the sun gear and the ring gear leads to premature wear of the teeth, requiring regular maintenance and increasing the operating costs of the turbine engine.

[0007] In the current technology, one solution to reduce this overload phenomenon is to pair the pivots of the planetary gear and the holes of the carrier during the processing and assembly of the components. Pairing includes connecting the pivots to the holes so that the pivots and holes of a pair are assembled together. One consequence of this pairing is that the pivots of the two pairs are not interchangeable.

[0008] Pairing makes it more complicated to manage the inventory of parts when assembling or maintaining the epicyclic gear train. In addition, the pairing operation is limited because complex assembly tasks are required before assembling the various components of the bracket, which leads to high production costs and makes maintenance operations more complicated.

[0009] One of the primary objects of the present invention is to reduce planetary gear positioning errors in a carrier in a simple, effective and economical manner without having to resort to component mating or to altering manufacturing tolerances of the carrier and pivot shafts, which can significantly increase manufacturing costs. Summary of the invention

[0010] To this end, the invention relates to a method for assembling an epicyclic or planetary gear train from at least one pivot shaft and a carrier comprising one or more holes, each hole being intended to receive a pivot shaft, the method comprising the following steps:

[0011] a) measuring the position of the real axis of each of the at least one pivot and one or more holes of the bracket;

[0012] b) dividing each of the pivots into n angular sectors i1 ... i extending around the theoretical axis of the pivot q ...i n , and divides each of the holes of the bracket into k angular sectors j1 ... j extending around the theoretical axis of the hole l ... k ;

[0013] c) For each pivot, define the vector from the theoretical axis to the real axis And identify including vector Angular sector i q ;

[0014] d) For each hole, define the vector from the theoretical axis to the real axis And identify including vector The angular sector j l ;

[0015] e) For each hole of the bracket, mount the pivot in such a way that for each component, the identified angular sector j l and i q are superimposed.

[0016] Imperfections in the position of the holes in the bracket and imperfections in the concentricity of the pivot lead to tangential deviations of the actual axis of rotation from the theoretical axis.

[0017] Therefore, although the pivot and the hole each have a true rotation axis (ie, actual rotation axis) eccentric to their theoretical rotation axis, the assembly according to the method of the invention makes it possible to minimize the eccentricity of the rotation axis caused by the pivot-hole assembly.

[0018] During assembly step e), the pivot is oriented in the support so that the vector and Not being arranged in the same angular sector allows the eccentricities of the pivot and the actual axis of rotation of the hole to partially compensate for each other.

[0019] Orientation of the components during assembly makes it possible to correct relative tangential positional defects of the planetary gears and thus reduce overloading phenomena of the planetary gears of the pivots and holes, without changing the manufacturing tolerances of the carrier holes and the pivots.

[0020] The method does not require pairing and also allows the interchangeability of parts during assembly or maintenance operations.Thus, whatever the pivot installed in one of the holes and the orientation of the pivot in the hole, the method according to the invention allows the defects arising from the pivot-hole assembly to be reduced.

[0021] Step e) of the method may also be performed by means of a positioning device comprising complementary connection means on the pivot and on the carriage.

[0022] The locating device allows the pivot to be oriented and secured in the hole in a desired orientation during assembly.

[0023] The connection means may comprise a first form-fitting connection carried by the bracket and a second form-fitting connection carried by the pivot. The first and second form-fitting connection means may also be referred to as first and second form-fitting connection means.

[0024] In this way, when the pivot is mounted in the hole, the first connection means carried by the bracket cooperate with the second connection means carried by the pivot so that the latter are oriented in the hole in such a way that the eccentricities of the pivot and the hole at least partially offset each other.

[0025] The first form-fitting connection means may comprise a first part arranged in the angular sector j l The second form-fitting connection device comprises an insertion opening of the first protruding member.

[0026] The first member may be adapted to be arranged in each of the k holes arranged around the hole and located in sector j l and step d) further comprises the following steps:

[0027] The first component is inserted into the lth hole located in the corner sector jl.

[0028] Each angular sector of each pivot may include second connection means formed by radial projections Eq at the periphery of the pivot, step c) comprising the execution of error-proofing when installing the opening of the radial projection Eq in said sector j1. The error-proofing process consists in removing radial projections not included in the identified angular sector iq.

[0029] Thus, once steps c) and d) of the method according to the invention have been carried out, each hole comprises a plurality of holes carried by the carriage and located at a position comprising the vector The angular sector j l and each pivot includes a radial protrusion E q , radial protrusion E q The radial protrusion E comprises an opening capable of cooperating with the member. q Located including vector Angular sector i q In this way, the angular sectors j of each hole and each pivot can be visually identified separately. l and i q It is easier to deduce the angular sector in which the actual axes of the hole and the pivot are located.

[0030] Step d) may also include the following steps:

[0031] Orient the pivot so that the first member carried by the bracket is inserted into the remaining radial projection E carried by the pivot q in the opening.

[0032] Therefore, by mounting the pivot so as to insert the member into the remaining radial projection E of the pivot q opening, ensuring that the pivot is mounted in the hole and oriented so that the angular sectors of the hole and the pivot are identified. l and i q Superimpose separately.

[0033] By superimposing the angular sector j l and i q , vector and Not being arranged in the same angular sector means that positional defects of the pivot axis and of the real axis of the hole at least partially compensate for each other.

[0034] In addition, the components and radial protrusions E q The fit of the opening allows for reduced orientation errors when mounting the pivot in the hole.

[0035] This approach is an industrially feasible solution which also avoids having to mate the holes of the bracket with the associated pivots.

[0036] The pivot and the hole are divided into n and k angular sectors respectively, so that n may be greater than or equal to k.

[0037] Thus, when n is greater than k, the position of the actual axis of rotation is more accurately identified on the pivot, while avoiding cutting the hole into as many angular sectors as possible. As mentioned above, each angular sector of the hole comprises holes arranged around the periphery of the hole on the bracket. Such a large number of holes on the bracket may lead to its mechanical weakening. Therefore, by limiting the number of angular sectors k so that n is greater than k, the mechanical weakening of the bracket caused by the formation of holes is reduced and better controlled.

[0038] In practical examples of embodiments of the present invention, n and k may be between 3 and 8, inclusive.

[0039] The invention also relates to an epicyclic or planetary gear train obtainable by the method described above.

[0040] Furthermore, the invention relates to an epicyclic gear train comprising a planetary carrier having a hole in which a pivot is arranged, the hole and the pivot comprising connecting means capable of cooperating with each other to retain the pivot in the hole in a predetermined orientation. The connecting means of the hole and the pivot are respectively arranged at a predetermined orientation comprising a vector oriented from the theoretical axis towards the real axis. The angular sector of and includes the vector In the angular sector of Oriented from the theoretical axis towards the real axis.

[0041] For example, the connection means of the aperture may comprise a protruding member.

[0042] Furthermore, the connecting means of the pivot may comprise an opening having a shape adapted to receive the connecting means of the aperture.

[0043] In addition, the opening is formed in the radial projection E carried by the pivot shaft. q and is suitable for receiving the protruding member.

[0044] The invention will be better understood and other details, characteristics and advantages of the invention will emerge when reading the following description given as non-limiting examples, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] - Figure 1 is a schematic front view of the gear train from the upstream axial direction;

[0046] - Figure 2 is a longitudinal schematic diagram of a turbine engine;

[0047] - Figure 3 is a schematic diagram of a planetary gear carrier according to the present invention;

[0048] - Figure 4 is a cross-sectional view of the pivot mounted in the hole of the bracket;

[0049] - Figure 5is the pivot according to the invention in angular sector i q Identify the previous schematic diagram;

[0050] - Figure 6 is a schematic diagram of the pivot, where the angular sector i q has been identified;

[0051] - Figure 7a , 7b and 7c respectively illustrate the steps of the method according to the present invention;

[0052] - Figure 8 is a schematic diagram of a gear train obtainable by the method according to the invention. DETAILED DESCRIPTION

[0053] Figure 1 The structure of an epicyclic gear train or planetary gear train 10 is schematically shown. This type of gear train 10 generally comprises an inner planet gear 12 (also called central pinion, sun or sun gear) and an outer planet gear 14 (also called ring gear), which are coaxial. The sun gear 12 is rotatable about its X axis, and the ring gear 14 can be fixedly or rotatably connected to a propeller, such as in the case of a twin-flow turbojet engine, such as a turboprop engine or a fan impeller. The gear train 10 also comprises planet gears 16 rotatably mounted on a pivot 18 of a planet gear carrier 20. Each planet gear 16 meshes with both the sun gear 12 and the ring gear 14. The carrier 20 is fixed or can rotate about the axis X of the sun gear 12 and the ring gear 14. The inlet can be formed by the sun gear 12 and the outlet by the planet gear carrier 20.

[0054] In another embodiment, the bracket 20 may be fixedly or rotatably connected to a propeller of a turboprop engine or a fan impeller of a twin-flow turbojet engine.

[0055] Figure 2 An aircraft turbine engine 22 is schematically shown, in which the gear train 10 is used as a speed reducer to reduce the rotation speed of a rotor, for example a fan wheel 24, independently of the rotation speed of at least one turbine 26 axially connected downstream to at least one compressor 28, with which the turbine engine is also equipped. The air first passes through a front air inlet 30, then the fan wheel 24 and the compressor 28.

[0056] The central pinion or sun gear 12 surrounds and is then rotationally fixed to the shaft 32 of the compressor 28, such as Figure 1 and Figure 2 In particular, Figure 2 As shown, the gear train 10 may be mounted in a radially formed annular chamber within a low pressure compressor 28a disposed downstream of the fan impeller 24 and upstream of the high pressure compressor 28b.

[0057] As from Figure 1 As can be seen in , the alignment of the teeth of the planetary gears with the teeth of the sun gear 12 and the teeth of the ring gear 14 is essential for the correct operation of the gear train 10 and to limit maintenance operations.

[0058] Improper positioning of the planetary gear 16 in the hole 34 of the carrier 20 (in Figure 3 ) causes the teeth of the planet gears 16 to be misaligned with the teeth of the sun gear 12 and the teeth of the ring gear 14. This results in a difference in the power transmitted through the planet gears 16, which causes early wear of the teeth.

[0059] Therefore, it is necessary to provide a solution to minimize the misalignment of the planetary gears 16 when assembling such a gear train 10 .

[0060] For this purpose, Figure 7a , 7 b and 7 c , an assembly method for the gear train 10 is presented. The mounting can be performed from at least one pivot 18 and a bracket 20 including one or more holes 34 .

[0061] Figure 3 An embodiment of a bracket 20 according to the invention is shown in which the epicyclic gear train is assembled. It has five holes 34 which are regularly distributed around the X axis and are dimensioned so that the pivot 18 can be mounted therein. Figure 5 One embodiment of the pivot 18 is shown in FIG. The pivot 18 includes a shaft 36 having a diameter sized so that it can be disposed in the hole 34 of the bracket 20. The shaft 36 is generally cylindrical or frustoconical in shape and extends at one end through an annular connecting portion 38 extending radially outward ( Figure 4 ).

[0062] exist Figure 4 It can also be seen in the figure that the pivot 18 is mounted in the hole 34 of the bracket 20. The shaft 36 of the pivot 18 is arranged in the hole 34 of the bracket 20 so that the connecting portion 38 rests on the surface 41 of the bracket 20 at the periphery of the hole.

[0063] exist Figure 7a , 7b and 7c, the method is applied to two holes 34, one bracket 20 or two separate brackets 20, and two pivots 18.

[0064] The first step of the method consists in measuring the position of the real axis of rotation 51 of each pivot 18 and the position of the real axis 40 of each hole 34 of the bracket. Figure 7a As shown, in this first step, the measurement gives the actual axis of rotation 51 ( Figure 4 ) relative to its theoretical rotation axis 52 and the position of the real axis 40 of each hole 34 relative to its theoretical axis 42.

[0065] For the hole 34, the eccentricity of the real axis 40 relative to the theoretical axis 42 is partly due to manufacturing defects, which affect in particular the position of the hole 34 in the bracket. In the case of the pivot 18, this eccentricity is explained by manufacturing defects, which affect in particular the concentricity of the pivot 18.

[0066] The three-dimensional position of the real axis of the pivot and the hole is measured separately using a special machine. This machine, by feeling the circumference of the hole and the pivot, allows the determination by calculation of the real position of the center and therefore the real axis of rotation of the pivot and of the hole.

[0067] Thus, a first step makes it possible to know the relative position of the real axis 40 of the hole 34 with respect to its theoretical axis 42 and the position of the actual axis of rotation 51 of the pivot 18 to be assembled with respect to its theoretical axis of rotation 52 .

[0068] To characterize the relative position of the real axis 40, 51 of each hole and pivot relative to their theoretical axis 42, 52, the vector and are defined in the third and fourth steps respectively, and are also shown in Figures 7a, 7b and 7c.

[0069] For each hole 34, define the vector Vector It is oriented from the theoretical axis 42 toward the real axis 40 and is equal in size to the distance between the theoretical axis of rotation 42 of the hole 34 and the real axis 40 .

[0070] Similarly, for each pivot 18, define the vector Vector It is oriented from the theoretical rotation axis 52 toward the actual rotation axis 51 and its size is equal to the distance between the theoretical rotation axis 52 and the actual rotation axis 51 of the pivot 18 .

[0071] In a practical implementation, compatible with the industrialization of the component, the method comprises a second step consisting in dividing the pivot 18 regularly and independently into several equal angular sectors, and in dividing the hole 34 of the bracket 20 into several equal angular sectors around their respective theoretical axis 42. Thus, the pivot 18 and the hole 34 are independently and regularly divided into n and k angular sectors extending around their respective theoretical axis 42, n and k possibly being equal, as Figure 7a , as shown in 7b and 7c, where n=k=4.

[0072] This division into angular sectors makes it possible to locate in which angular sector of the component lies the vector and And thus locate the real axis of rotation 51 of the pivot 18 and the real axis 40 of the hole 34. The orientation of each hole and the pivot can then be derived.

[0073] This division into angular sectors also makes it possible to identify in the third and fourth steps the regions respectively comprising the vectors and The angular sector i of each pivot 18 and each hole 34 q and j l .

[0074] Figure 7c The fifth step of the method shown in FIG. 1 comprises mounting one of the pivots 18 in the hole 34 and orienting it angularly so that, for each assembly 44, the identified angular sector j l and i q In other words, the pivot 18 is mounted and oriented in a hole 34 so that the actual axis of rotation 51 of the pivot 18 and the actual axis 40 of the hole 34 of the assembly 44 (represented by the vector and definition) at least partially complement each other.

[0075] For this purpose, the pivot 18 is oriented so that the identified angular sector j l and i q are superimposed.

[0076] like Figure 7c As shown, the pivot 18 can be mounted indifferently in either hole 34. However, during assembly 44, the pivot 18 is mounted so that the vector and are not in the same angular sector, i.e., such that the identified angular sector j l and i q are superimposed.

[0077] This method does not require mating parts, so the pivot 18 can be installed in all holes 34 as long as the orientation of the pivot 18 is respected.

[0078] In practice, the fifth step of the method is performed by a positioning device. The positioning device comprises additional connection means on the pivot 18 and on the bracket 20. The positioning device allows the pivot 18 to be oriented in the hole 34 of the bracket 20 and fixed in the desired orientation during assembly. In practice, as will be understood below, when installing the pivot 18 in the hole 34, the device performs error prevention, avoiding improper installation of the pivot 18 in the hole 34, which, contrary to the desired result, would result in an increase in tooth misalignment.

[0079] like Figure 7a , 7bAs shown in 7c and 7c, the connection means comprise first form-fit connection means carried by the bracket. These first connection means comprise first members 56 which can be arranged in a protruding position in holes 48 arranged around the periphery of the holes 34. In particular, the holes 48 are arranged so that there is only one hole 48 for each angular sector of each hole 34 of the bracket 20, as shown in FIG. Figure 3 shown.

[0080] For each hole 34, the fourth step of the method also comprises inserting a first member 46 located in the angular sector j l The steps of the holes 48 in the angular sector j l The vector for each hole 34 is included This step thus allows, for each hole 34, visually identifying the angular sector in which the real axis 40 of the hole 34 lies and providing a connection means that will help to "orient" the pivot 18 in the hole 34, i.e., the angular position that results in reduced tooth misalignment. Figure 7b , which partially illustrates this step, the pins are arranged in a vector including the two holes 34 In the angular sectors j2 and j4.

[0081] like Figure 7a , 7b and 7c, the connection means comprises a second form-fit connection means carried by the pivot 18. The second form-fit connection means comprises an introduction opening 50, so that the first member 46, such as a pin, can be received in the introduction opening 50. In particular, as Figure 5 As shown, each pivot comprises a second connection means which is a radial protrusion E on the circumference 53 of the pivot 18. q The radial protrusion E at the periphery 53 of the pivot 18 q can be arranged at the periphery of the connecting portion 38. In particular, these radial protrusions E q Arranged so that each angular sector of each pivot 18 has only one protrusion E q ,like Figure 7a shown.

[0082] For each pivot 18, the third step of the method also comprises installing the sector j l The radial protrusion E in the member 46 q The error-proofing process includes removing the corners not included in the identified angular sector i. q The radial protrusion E q , angular sector i q Includes Vector-V →Thus, for each pivot 18, this step allows visual identification of the angular sector located in the opposite direction to the angular sector in which the real axis of rotation 51 of the pivot 18 is located, and provides connection means that will subsequently facilitate the “directional” mounting of the pivot 18 in the hole 34. After machining, the pivot 18 has only one radial protrusion, such as Figure 6 shown.

[0083] After the third and fourth steps of the method, Figure 7b As shown, the pin 46, the first form-fitting connection means carried by the bracket and the remaining radial projection E q , a second form-fitting connection carried by the pivot allows direct or indirect identification of the vector and position and direction.

[0084] In a practical embodiment of the method, the fifth step consists in orienting the pivot 18 so as to insert the first protruding member 46 carried by the bracket 20 into the remaining radial protrusion E carried by the pivot 18. q The steps in the opening. Figure 7c As shown, the pivot 18 is oriented in the hole 34 so that the pin 46 of the hole 34 is aligned with the remaining radial projection E of the pivot 18. q The fit ensures that the actual rotation axis 51 of the pivot 18 and the actual axis 40 of the hole 34 are not in the same angular sector.

[0085] By superimposing a visually identifiable angular sector j on each hole 34 and pivot 18 l and i q , ensure that during assembly, and The arrangement is in such a way that the real axis of rotation 51 of the pivot 18 and the real axis 40 of the hole 34 of the component 44 at least partially compensate for one another.

[0086] like Figure 8 As shown, this method produces a planetary gear train 60, in which the remaining radial protrusion E of the pivot shaft 18 is utilized. q The engagement with the pins 46 disposed about the hole 34 orients the pivot shaft 18 in the hole 34 .

[0087] like Figure 7c As shown, the pivots 18 are interchangeable: they can be installed in either hole 34, as long as the pivots 18 use their remaining radial projections E q Just orient it correctly.

[0088] In the specific case, for hole 34, the vector Located on the boundary between two angular sectors, one of the two sectors is randomly selected as the region containing the vector Similarly, for pivot 18, when the vector When it is on the boundary between two angular sectors, one of the two sectors is randomly selected as the inclusion vector According to one embodiment of the invention, the pivot 18 and the hole 34 are in n and k angular sectors, respectively, such that n may be greater than or equal to k.

[0089] According to another embodiment, n and k may be between 3 and 8, inclusive.

[0090] In particular, by limiting the number of angular sectors of the hole 34, the number of holes 48 drilled around the perimeter of the hole 34 on the bracket 20 is also limited. This allows the weakening of the bracket 20 by the hole 48 to be limited and controlled.

Claims

1. A method for assembling an epicyclic or planetary gear train (10) from at least one pivot shaft (18) and a planet gear carrier (20), the planet gear carrier (20) comprising one or more holes (34), each hole (34) being adapted to receive the pivot shaft (18), the method comprising the following steps: a) measuring the position of the real axis of each of the at least one pivot shaft (18) and one or more holes (34) of the planet gear carrier (20); b) dividing each of said pivots (18) into n angular sectors i1 ... i extending around the theoretical axis of said pivot q ...i n and divides each of the holes (34) of the planetary gear carrier (20) into k angular sectors j1 ... j extending around the theoretical axis of the hole (34) l ... k ; c) For each pivot (18), define the vector from the theoretical axis of the pivot to the real axis of the pivot and identify the vectors including - Angular sector i q ; d) For each hole (34), define the vector from the theoretical axis of the hole to the real axis of the hole And identify including vector The angular sector j l ; e) For each hole (34) of the planetary gear carrier (20), the pivot (18) is mounted so that for each assembly (44), the angular sector j identified l and i q are superimposed.

2. Method according to claim 1, wherein step e) is performed with the aid of a positioning device comprising complementary connection means on the pivot and on the planet carrier.

3. The method according to claim 2, characterized in that The connection device comprises a first form-fitting connection device carried by the planet gear carrier (20) and a second form-fitting connection device carried by the pivot (18).

4. The method according to claim 3, wherein the first form-fitting connection means comprises a first shape-fitting connection means arranged in an angular sector j l A first protruding member (46) is provided in the embodiment of the present invention, and wherein the second form-fitting connection device comprises an opening (50) adapted to receive the first protruding member.

5. A method according to claim 4, wherein the first protruding member (46) is adapted to be received in each of k holes (48) arranged around the hole (34) and located in sector j. l and wherein step d) further comprises the following steps: The first protruding member (46) is inserted into the lth hole (48) located in the angular sector j1.

6. A method according to claim 4 or 5, wherein each angular sector of each pivot (18) comprises second connecting means formed by radial projections (Eq) at the periphery (53) of the pivot (18), step c) comprising: When installing the opening (50) of the radial protrusion (Eq) in said member (46) of sector j1, error proofing is performed.

7. The method according to claim 6, wherein: The execution of the error prevention comprises removing radial protrusions (Eq) not included in the angular sector iq.

8. The method according to claim 7, wherein step d) further comprises the following steps: Directional The pivot shaft (18) is arranged to insert a first protruding member (46) carried by the planetary gear carrier (20) into an opening (50) of a remaining radial protrusion (Eq) carried by the pivot shaft (18).

9. The method of claim 1, wherein n is greater than or equal to k.

10. The method according to any one of claims 1 to 9, wherein n and k are from 3 to 8, inclusive.

11. A planetary gear train (60) obtainable by the method according to any one of claims 1 to 10.

12. A planetary gear train (60), comprising a planetary gear carrier (20) having a hole (34), a pivot shaft (18) being arranged in the hole (34), the hole (34) and the pivot shaft (18) comprising connecting means adapted to cooperate with each other to hold the pivot shaft (18) in the hole (34) in a predetermined orientation, the means for connecting the hole (34) and the pivot shaft (18) being arranged respectively on a line including a vector oriented from a theoretical axis of the hole toward a real axis of the hole The angular sector of and includes the vector In the angular sector of Oriented from the theoretical axis of the pivot towards the real axis of the pivot.

13. The planetary gear train according to claim 12, characterized in that: The connection means of the aperture (34) comprises a protruding member (46).

14. The planetary gear train according to claim 13, characterized in that: The connection means of the pivot (18) comprises an opening (50) having a shape adapted to receive the connection means of the hole (34).

15. The planetary gear train (60) according to claim 14, characterized in that: The opening (50) is formed in a radial protrusion (Eq) carried by the pivot (18) and is suitable for receiving the protruding member (46).

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