LINKING DEVICE BETWEEN ELEMENTS, IN PARTICULAR ROTARY ELEMENTS OF AN AIRCRAFT TURBOMACHINE, GEARBOX AND TURBOMACHINE EQUIPPED WITH SUCH A DEVICE

Abstract

This linking device between a first element (25) and a second element (26) of an aircraft comprises means for axially fixing the first element (25) and the second element (26) and means for rotationally locking said first element (25) and said second element (26), the rotationally locking means comprising splines provided on the first element (25) engaging with complementary splines provided in the second element (26). The axial fixing means comprise a stop attached to the second element, the second element (26) being held by means of a nut (33) screwed against said stop. Figure for the abbreviation: Fig 5

Description

Title of the invention: LINKING DEVICE BETWEEN ELEMENTS, IN PARTICULAR ROTARY ELEMENTS OF AN AIRCRAFT TURBOMACHINE, GEARBOX AND TURBOMACHINE EQUIPPED WITH SUCH A DEVICE Technical field

[0001] The invention relates, in general, to a linking device between elements, in particular but not exclusively rotating elements of an aircraft turbomachine.

[0002] The invention relates in particular, in a non-limiting application, to mechanical gearboxes for aircraft turbomachinery and more specifically to the assembly of a gearbox output shaft and a fan shaft. Prior art

[0003] The role of a mechanical reducer is to modify the speed and torque ratio between the input shaft and the output shaft of a mechanical system.

[0004] With regard to aircraft turbomachinery, and in particular double-flow turbomachinery, especially those with a very high bypass ratio, the mechanical reducer has the role of driving the shaft of a fan by transforming the so-called high rotational speed of the shaft of a power turbine into a slower rotational speed for the shaft driving the fan.

[0005] Such a reducer comprises a central pinion, called a solar, a ring gear and pinions called satellites which are meshed between the solar and the ring gear.

[0006] The satellites are held by a frame called a satellite carrier. The solar array, the corona, and the satellite carrier are planetary because their axis of revolution coincides with the longitudinal axis of the turbomachine.

[0007] The satellites have different axes of revolution distributed over the same operating diameter around the axis of the planetary gears

[0008] These axes are parallel to the longitudinal axis.

[0009] There are several reducer architectures.

[0010] In the state of the art of double-flow turbomachinery, the reducers are of the planetary or epicyclic type.

[0011] On a planetary gearbox, the planet carrier is fixed and the ring gear constitutes the shaft output of the device which rotates in the opposite direction to the solar system.

[0012] On an epicycloidal reducer, the ring is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the sun.

[0013] On a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the sun and the satellite carrier.

[0014] The blower is driven by the gearbox. The blower shaft is therefore connected to the gearbox output shaft.

[0015] In this regard, reference may be made to the unpublished patent application filed in the name of the applicant under number FR 2407847, which describes a gearbox for an aircraft turbomachine, comprising a fan shaft and a planet carrier separate from the fan shaft and comprising means for rotationally locking and means for axially fixing the fan shaft and the planet carrier, the means for rotationally locking comprising a groove provided on the planet carrier, engaging with a corresponding groove on the fan shaft.

[0016] In an embodiment illustrated in [Fig.1], the blower shaft 1 and the planet carrier 2 are rotationally secured by means of securing means comprising a straight male spline 3 carried by the planet carrier 2 and a female spline 4 carried by the blower shaft 1.

[0017] The blower shaft 1 and the satellite carrier s 2 are fixed axially by means of a nut 5 which is screwed into an external thread of an axial cylindrical bearing 6 of the blower shaft 1, against an annular stop 7 of the satellite carrier 2. During assembly, the nut must be captive in the satellite carrier 2 during the assembly of the various gears of the reducer, namely solar, satellites, and ring gears, which makes the assembly complex to implement.

[0018] In another embodiment illustrated in figures 2 and 3, the nut 5 is screwed onto a cylindrical bearing surface 8 extending from the planet carrier 2, against an annular stop 9 extending radially from the wall of the blower shaft 1.

[0019] In order to allow the insertion of the nut 5 from the end of the blower shaft, the stop 9 is made in the form of a set of sectors 10 configured so as to allow the passage of the nut 5 in the blower shaft in an inclined position.

[0020] With such an arrangement, shocks are likely to occur during the insertion of the nut so that the blower shaft is likely to be damaged. Description of the invention

[0021] In view of the foregoing, a first object of the invention is to propose a linking device between two elements, which avoids the aforementioned disadvantages.

[0022] Another object of the invention is to provide an aircraft turbomachine gearbox, in which the fan shaft and the gearbox output shaft are rotationally linked by means of a linkage device that ensures torque transfer, and whose The assembly is simple to implement, without risk of damaging the assembled elements.

[0023] The invention therefore relates to a linking device between a first element and a second element of an aircraft, comprising means for axially fixing the first element and the second element and means for rotationally locking said first element and said second element, the rotationally locking means comprising a groove provided on the first element engaging with a complementary groove provided in the second element.

[0024] The axial fixing means include a stop attached to the second element, the second element being held by means of a nut screwed against said stop.

[0025] In one embodiment, the first element is held by screwing against the stop.

[0026] The first element may further include a bearing pressed against the second element by means of the nut.

[0027] Advantageously, the stop is screwed onto a thread made in the second element, the thread having an axial dimension greater than that of a complementary thread of the stop.

[0028] In one embodiment, the second element includes an axial support shoulder for the added stop, on which the stop rests at the end of screwing.

[0029] In this case, it can be assumed that the nut and the stop have threads in opposite directions.

[0030] In one embodiment, the first element is an output shaft of a reducer aircraft turbomachine.

[0031] The second element can be an aircraft turbomachine blower shaft.

[0032] The invention also relates to a method for connecting a first element and a second element of an aircraft, comprising the steps of: - Inserting a nut into the second element; - Fixing an axial stop attached to the second element; - Rotational locking of the first and second elements by means of grooves provided on the first element engaging with complementary grooves provided in the second element; and - Screw the nut onto the first element against the stop so as to axially hold the first element

[0033] The invention further relates to a gearbox for an aircraft turbomachine, comprising an output shaft and a linkage device for connecting the gearbox output shaft to a fan shaft, the linkage device comprising means for axially fixing the output shaft and the fan shaft and means for rotational locking of the output shaft and the blower shaft, the rotational locking means comprising splines provided on the output shaft engaging with complementary splines provided in the blower shaft.

[0034] The axial fixing means comprise a stop attached to the blower shaft, the blower shaft being held by means of a nut screwed against said stop.

[0035] The invention further relates to an aircraft turbomachine, comprising a reducer as defined above. Brief description of the drawings

[0036] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0037] Figs. 1, 2 and 3 illustrate the assembly of a satellite carrier and a blower shaft according to the prior art;

[0038] Figure 4 schematically illustrates an aircraft turbomachine equipped with a linkage device according to the invention;

[0039] Fig. 5 is a cross-sectional view of a blower shaft and a planet carrier of the turbomachine gearbox of Fig. 4, assembled by means of a linkage device according to the invention;

[0040] Figures [Fig. 6a], [Fig. 6b], [Fig. 6c], [Fig. 6d] and [Fig. 6e] illustrate the main steps of an assembly process according to the invention; and

[0041] Figures [Fig.7] and [Fig.8] illustrate alternative embodiments of the axial stop. Detailed description

[0042] Figure 4 shows a turbomachine for an aircraft according to the invention, designated by the general numerical reference 11, with axis XX.

[0043] This turbomachine 1 is a double-flow turbojet which includes at the front, considering the direction of the airflow admitted into the turbojet, a fan 12 which is connected to a reducer 13, then a low-pressure compressor 14 and a high-pressure compressor 15 which supplies air to a combustion equipment 16.

[0044] The turbomachine 11 comprises, downstream of the combustion equipment 16, a high-pressure turbine 17 and, further downstream, a low-pressure turbine 18.

[0045] The hot gases from the combustion pass through the low-pressure turbine 18 which drives the blower before escaping through an exhaust nozzle 19.

[0046] The assembly comprising the reducer 13, the low-pressure compressors 14 and high-pressure compressors 15, as well as the combustion equipment 16 and the high-pressure turbines 17 and low-pressure turbines 18 are placed in an inner casing 20 which is surrounded by an outer annular casing 21 held by radial spacers 22 connecting the casings 20 and 21.

[0047] The low-pressure compressor and the low-pressure turbine are connected by a low-pressure shaft 23. The high-pressure compressor and the high-pressure turbine are connected by a high-pressure shaft 24. The blower is driven by a blower shaft 25 which is driven by the low-pressure shaft 23 by means of the reducer 13.

[0048] This reducer is generally of the planetary or epicycloidal type.

[0049] As previously stated, in an epicyclic gearbox, the planet carrier constitutes the output shaft of the gearbox, which rotates in the same direction as the sun gear. In a planetary gearbox, the ring gear constitutes the output shaft of the gearbox, which rotates in the opposite direction to the sun gear.

[0050] On a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the sun and the satellite carrier.

[0051] The turbomachine is also equipped with a linking device which ensures the connection between two elements of the turbomachine so as to ensure the axial and rotational locking of these elements.

[0052] In one embodiment, the linking device is a linking device between a first element consisting of the output shaft 25 of the reducer and a second element consisting of the blower shaft 26, which ensures the rotational locking and axial fixing of the output shaft of the reducer and the blower shaft.

[0053] In [Fig.5], the planet carrier of the reducer 13 and the blower shaft 26 are shown. The reducer is here an epicyclic reducer so that the output shaft 25 of the reducer is constituted by the planet carrier.

[0054] The planet carrier 25 and the blower shaft 26 each comprise a proximal end I intended to receive the driving torque, with regard to the planet carrier 25, and to transmit the driving torque to the blower, with regard to the blower shaft 26, and a distal coupling end II at which the planet carrier 25 and the blower shaft 26 are rotationally secured and axially fixed.

[0055] The linkage device between the output shaft of the reducer and the blower shaft includes rotational locking means comprising a male spline 27 carried by an axial cylindrical extension 28 of the planet carrier 25 and a female spline 29 carried by the blower shaft 26.

[0056] The female spline of the blower shaft 26 is formed internally in an annular spacer 30 which extends radially from the blower shaft 26 and which externally has an external radial surface S supporting a main bearing (not shown).

[0057] Advantageously, as shown, the spacer 30 is provided with grooves 31 at 360° around the spacer, which lighten the spacer and allow for mechanically dissociate the splines 27 and 29 and the main bearing by locally creating a flex zone in the vicinity of the main bearing support zone.

[0058] It should be noted, however, that the spacer 30 and the grooves 31 are optional. It is indeed possible to bring the splines of the main bearing closer together radially.

[0059] The linkage device between the blower shaft and the output shaft of the reducer further includes axial fixing means 32 of the blower shaft and the planet carrier.

[0060] The planet carrier 25 and the blower shaft 26 are fixed axially by means of a nut 33 screwed onto a cylindrical bearing surface 34 extending from the cylindrical extension 28 of the planet carrier 25. This nut is screwed against an axial stop 35 which extends radially inwardly from the wall of the blower shaft 26 and against which is pressed a radial annular bearing surface 36 of the planet carrier provided between the cylindrical extension 28 and the cylindrical bearing surface 34.

[0061] By axial stop, we mean a stop that supports the forces applied during the tightening of the nut in an axial direction parallel to the axis XX of the turbomachine. It is an annular stop that is clamped during screwing between the nut and the planet carrier.

[0062] To avoid pre-mounting the spare nut 33 in the planet carrier during the assembly of the gearbox pinions, namely the sun gear, planet gears, and ring gears, the axial stop 35 is attached to the blower shaft. Thus, the stop can be fixed to the blower shaft after the nut has been inserted from the distal end II of the blower shaft.

[0063] Thus, with reference to Figures 6a to 6e, the assembly of the gearbox output shaft and the blower shaft is carried out, starting from the blower shaft 26 alone ([Fig. 6a]), by inserting the nut 33 into the blower shaft ([Fig. 6b]). The axial thrust bearing 35 is then attached to the blower shaft ([Fig. 6c]), and then the splines 29 of the planet carrier are engaged in the corresponding splines 27 of the blower shaft to lock the planet carrier 25 and the blower shaft 26 in rotation ([Fig. 6d]). The nut 33 is then tightened to clamp the axial thrust bearing 35 between the nut and the radial annular shoulder of the planet carrier ([Fig. 6e]).

[0064] The assembly is then blocked in rotation by the splines 27 and 29 and axially by the stop 35.

[0065] Advantageously, the stop 35 is attached to the blower shaft by screwing, providing additional threads on the outer periphery of the stop and on an inner peripheral surface of the blower shaft. Alternatively, the stop can be attached by shrink fitting (either circular or more complex, for example, trilobular type P3G), welding, bonding, or any other suitable assembly method.

[0066] It should be noted, however, that when the stop is screwed in, an external thread with an axial dimension larger than that of the stop's thread can be provided on the blower shaft in order to adjust the axial position of the planet carrier relative to the blower shaft by tightening or loosening the stop. This adjustment can prove useful when combined with dimensional measurements to compensate for manufacturing errors.

[0067] Still in the case of a screw-on stop, the stop 35 can be clamped between the nut and the planet carrier, as described previously. The axial locking of the planet carrier and the blower shaft in both directions is thus achieved by the stop. However, in the case of a stop attached by means other than a thread, it is possible to achieve axial locking in one direction by the nut 33 on the stop 35 and in another directly by providing an additional support 37 between the planet carrier and the blower shaft, for example by bringing the annular spacer 30 into contact with the planet carrier, as illustrated in [Fig. 7].

[0068] Alternatively, if it is not desired to take advantage of the opportunity for adjustment in the case of a thread, the internal peripheral surface of the blower shaft in which the thread is formed can be provided with a stop at the end of the thread, as illustrated in [Fig.8], in the form of an axial support shoulder 38. Thus, the axial stop can be tightened to the bottom of the thread in a predefined fixed position.

[0069] Advantageously, the threads of the stop and the nut have opposite directions, so that the nut can be tightened against the stop without unscrewing the stop. It should be noted that, in this embodiment, the stop can be pinched between the nut and the planet carrier, or can provide a stop in only one direction, additional support being provided between the planet carrier and the blower shaft, for example by bringing the annular spacer 30 into contact with the planet carrier, as described previously with reference to [Fig. 7].

[0070] The embodiments described above with reference to figures 5 to 8 relate to an epicycloidal reducer.

[0071] However, we do not depart from the scope of the invention when the reducer is a planetary or differential reducer, to ensure rotational locking and axial locking of the reducer output shaft with the blower shaft, whether for reducers with straight or herringbone teeth, with one or more stages.

[0072] Finally, it should be noted that in the embodiments described above, the linkage device ensures axial locking and rotational locking of the output shaft of the reducer and the blower shaft.

[0073] The invention relates, however, in general, to a connecting device that ensures the connection between two rotating elements of the turbomachine. Such a device, which includes fastening means having grooves provided on the two rotating elements and axial fixing means including a nut screwing onto an added stop, can also be used to ensure the connection between other rotating elements of an engine, for example to ensure the connection between the low pressure turbine and the input shaft of the reducer, or between the high pressure compressor and the high pressure turbine,... or within an aircraft turboprop, for example to ensure the connection between a reducer and a transmission shaft.

[0074] Such a device according to the invention can also be used in landing gear wheel drive systems, for example to provide the connection between the output shaft of a landing gear gearbox and the wheel, or between a landing gear motor and the gearbox input. It is also applicable in all the aforementioned applications to static parts.

Claims

Demands

1. A linking device between a first element (25) and a second element (26) of an aircraft, comprising means for axially fixing the first element (25) and the second element (26) and means for rotationally securing said first element (25) and said second element (26), the rotationally securing means comprising grooves (27) provided on the first element (25) engaging with complementary grooves (29) provided in the second element (26), characterized in that the axial fixing means comprise a stop (35) attached to the second element (26), the second element (26) being held by means of a nut (33) screwed against said stop (35).

2. A linking device according to claim 1, in which the first element (25) is held by screwing against the stop.

3. A connecting device according to any one of claims 1 and 2, wherein the first element (25) has a bearing surface (36) pressed by means of the nut against the second element.

4. A connecting device according to any one of claims 1 to 3, wherein the stop (35) is screwed onto a thread made in the second element (26), the thread having an axial dimension greater than that of a complementary thread of the stop.

5. A linking device according to any one of claims 1 to 4, wherein the second element (26) has an axial support shoulder (38) for the added stop (35), on which the stop rests at the end of screwing.

6. A connecting device according to claim 5, wherein the nut (33) and the stop (35) have threads in opposite directions.

7. A linkage device according to any one of claims 1 to 6, wherein the first element (25) is an output shaft of an aircraft turbomachine reducer.

8. A linking device according to any one of claims 1 to 7, wherein the second element (26) is an aircraft turbomachine blower shaft.

9. A method for joining a first element and a second element of an aircraft, characterized in that it comprises the steps of: Insertion of a nut (33) into the second element (26); - Fixing of an axial stop (35) attached to the second element (26); - Rotational locking of the first element (25) and the second element (26) by means of grooves (27) provided on the first element engaging with complementary grooves (29) provided in the second element (26); and - Screwing the nut (33) onto the first element (25) against the stop (35) so as to axially hold the first element

10. Aircraft turbomachine gearbox, comprising an output shaft and a linkage device for linking the output shaft (25) of the gearbox to a fan shaft (26), the linkage device comprising means for axially fixing the output shaft (25) and the fan shaft (26) and means for rotationally locking the output shaft (25) and the fan shaft (26), the rotationally locking means comprising splines provided on the output shaft (25) engaging with complementary splines provided in the fan shaft (26), characterized in that the axial fixing means comprise a stop (35) attached to the fan shaft (26), the fan shaft (26) being held by means of a nut screwed against said stop (35).

11. Aircraft turbomachine, comprising a reducer according to claim 10.