(19)
(11)EP 2 831 403 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
09.09.2020 Bulletin 2020/37

(21)Application number: 13768646.5

(22)Date of filing:  25.03.2013
(51)International Patent Classification (IPC): 
F02K 3/00(2006.01)
F02C 7/36(2006.01)
F02C 7/00(2006.01)
F02K 99/00(2009.01)
(86)International application number:
PCT/US2013/033643
(87)International publication number:
WO 2013/148542 (03.10.2013 Gazette  2013/40)

(54)

GAS TURBINE ENGINE FAN DRIVE GEAR SYSTEM DAMPER

LÜFTERANTRIEBSSYSTEMDÄMPFER FÜR EINEN GASTURBINENMOTOR

AMORTISSEUR DE SYSTÈME D'ENGRENAGE D'ENTRAÎNEMENT DE VENTILATEUR DE TURBINE À GAZ


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 28.03.2012 US 201213432699

(43)Date of publication of application:
04.02.2015 Bulletin 2015/06

(73)Proprietor: United Technologies Corporation
Farmington, CT 06032 (US)

(72)Inventors:
  • COFFIN, James B.
    Windsor, Connecticut 06095 (US)
  • OTTO, John R.
    Middletown, CT 06457 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
EP-A1- 2 339 146
WO-A1-95/27860
US-A1- 2011 123 326
EP-A1- 2 339 146
JP-A- S61 286 531
US-A1- 2011 130 246
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND



    [0001] This disclosure relates to a damper for a fan drive gear system for a gas turbine engine.

    [0002] Gear trains are used in gas turbine engines to provide a gear reduction between a turbine section and a fan, for example. The gear train is supported relative to a static structure. During operation, the gear train generates vibrational inputs to the static structure and other components, which may be undesirable. Additionally, the supporting structure may transmit vibrational inputs to the fan drive gear system that may be coincident or undesirable to the fan drive gear system. Typically, a flex support having a bellow secures the gear train to the static structure to permit some relative movement between the gear train and the static structure.

    [0003] EP 2339146 discloses a prior art fan drive gear system as set forth in the preamble of claim 1.

    [0004] WO 95/27860 discloses a prior art coupling system.

    SUMMARY



    [0005] According to the invention, there is provided a fan drive gear system for a gas turbine engine as set forth in claim 1.

    [0006] In an embodiment of the above, the first member is a torque frame. The second member is a flex support having a bellow. The flex support is grounded to a static structure.

    [0007] In a further embodiment of any of the above, the torque frame and flex support are secured to one another by fasteners in an area spaced radially inward from the location.

    [0008] In a further embodiment of any of the above, multiple dampers are arranged circumferentially between the torque frame and the flex support. The bellow is provided between fasteners and the dampers.

    [0009] In a further embodiment of any of the above, the torque frame supports a carrier to which star gears are mounted. A sun gear is arranged centrally relative to and intermeshes with the star gears. A ring gear circumscribes and intermeshes with the star gears.

    [0010] In a further embodiment of any of the above, a fan is coupled to the ring gear and a low speed spool is coupled to the sun gear.

    [0011] In a further embodiment of any of the above, the tube provides a cavity. An orifice is provided in the tube in fluid communication with the cavity. The cavity provides a viscous damping chamber between the first and second members.

    [0012] In a further embodiment of any of the above, at least one of the gear train and the second member is configured to produce a vibrational input. The orifice and viscous damping chamber is configured to damp the vibrational input.

    [0013] In a further embodiment of any of the above, each end includes an annular groove that receives a respective seal and lateral sides are provided on each end with the respective end's annular groove provided between the lateral sides. The lateral sides provide annular tapers that extend radially inward away from the respective end's annular groove and are configured to permit articulation of the damper relative to the first and second members.

    [0014] In a further embodiment of any of the above, the tube includes a neck arranged between ends and has a diameter that is smaller than a diameter of the ends.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0015] The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

    Figure 1 schematically illustrates a gas turbine engine embodiment.

    Figure 2 is a schematic view of an epicyclic gear train embodiment for a fan drive gear system.

    Figure 3 is a partial cross-sectional schematic view of a fan drive gear system embodiment.

    Figure 4 is an enlarged view of a portion of the fan drive gear system shown in Figure 2.

    Figure 5 is a perspective view of a damper embodiment shown in Figure 4.


    DETAILED DESCRIPTION



    [0016] Figure 1 schematically illustrates a gas turbine engine 20. The gas turbine engine 20 is disclosed herein as a two-spool turbofan that generally incorporates a fan section 22, a compressor section 24, a combustor section 26 and a turbine section 28. Alternative engines might include an augmentor section (not shown) among other systems or features. The fan section 22 drives air along a bypass flowpath B while the compressor section 24 drives air along a core flowpath C for compression and communication into the combustor section 26 then expansion through the turbine section 28. Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures.

    [0017] The engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided.

    [0018] The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42, a low pressure (or first) compressor section 44 and a low pressure (or first) turbine section 46. The inner shaft 40 is connected to the fan 42 through a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 50 that interconnects a high pressure (or second) compressor section 52 and high pressure (or second) turbine section 54. A combustor 56 is arranged between the high pressure compressor 52 and the high pressure turbine 54. A mid-turbine frame 57 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46. The mid-turbine frame 57 supports one or more bearing systems 38 in the turbine section 28. The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A, which is collinear with their longitudinal axes. As used herein, a "high pressure" compressor or turbine experiences a higher pressure than a corresponding "low pressure" compressor or turbine.

    [0019] The core airflow C is compressed by the low pressure compressor 44 then the high pressure compressor 52, mixed and burned with fuel in the combustor 56, then expanded over the high pressure turbine 54 and low pressure turbine 46. The mid-turbine frame 57 includes airfoils 59 which are in the core airflow path. The turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.

    [0020] The engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than ten (10), the geared architecture 48 is an epicyclic gear train, such as a star gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine 46 has a pressure ratio that is greater than about 5. In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 44, and the low pressure turbine 46 has a pressure ratio that is greater than about 5:1. Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans.

    [0021] A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section 22 of the engine 20 is designed for a particular flight condition -- typically cruise at about 0.8 Mach and about 35,000 feet (10,668 m). The flight condition of 0.8 Mach and 35,000 ft (10,668 m), with the engine at its best fuel consumption - also known as "bucket cruise Thrust Specific Fuel Consumption ('TSFC')" - is the industry standard parameter of lbm of fuel being burned per hour divided by lbf of thrust the engine produces at that minimum point. "Fan pressure ratio" is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane ("FEGV") system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. "Low corrected fan tip speed" is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tambient deg R) / 518.7)^0.5] (where °R = K x 9/5). The "Low corrected fan tip speed" as disclosed herein according to one non-limiting embodiment is less than about 1150 ft / second (350.5 m/s).

    [0022] An example geared architecture 48 is schematically shown in a gear compartment 96 in Figures 2 and 3. The geared architecture 48 includes a sun gear 60, which is coupled to the inner shaft 40, as illustrated in Figure 3. Star gears 62 are arranged circumferentially about the sun gear 60 and intermesh with the sun gear 60 and a ring gear 64, which circumscribes the star gear 62. In one example, the ring gear 64 is coupled to the fan 42. It should be understood that the geared architecture 48 illustrated in Figures 2 and 3 is exemplary only and can be configured other than illustrated.

    [0023] A carrier 66 supports the star gears 62 relative to the sun gear 60 and ring gear 64. A torque frame 68 is connected to the carrier 66 by pins 70. The torque frame 68 is secured to the static structure 36 by a flex support 72, which has a bellow for permitting slight movement of the geared architecture 48 relative to the static structure 36. In the example, fasteners 73 secure the torque frame 68 and the flex support 72, which are metallic in one example, to one another to facilitate assembly and disassembly of the geared architecture 48. However, the torque frame 68 and flex support 72 are also spaced apart from one another in an axial direction at a location radially outward from the fasteners 73.

    [0024] Referring to Figures 3 and 4, the torque frame 68 and flex support 72 respectively include first and second apertures 74, 76 that are aligned with one another in the axial direction. A damper 78, which is metallic in one example, is provided between the torque frame 68 and flex support 72 and received within the first and second apertures 74, 76, the geared architecture 48, provide desired stiffness and/or avoid natural frequencies. In one example, multiple dampers are arranged circumferentially between the torque frame 68 and flex support 72, as illustrated in Figure 2. It should be understood that the dampers 78 may be configured in any desirable configuration and more or fewer dampers 78 may be used than illustrated.

    [0025] Referring to Figure 4 and 5, the damper 78 is provided by a tube 79 includes opposing ends 80 with a neck 82 arranged between the ends 80. The neck 82 has a diameter that is smaller than a diameter of the ends 80. Each end 80 includes an annular groove 84 that receives a seal 92. Lateral sides 86 are provided on each end 80 with the annular groove 84 arranged between the lateral sides 86. The lateral sides 86 provide an annular taper that extends radially inward from the annular groove 84. The smaller diameter neck 82 and the tapered lateral sides 86 enables the damper 78 to articulate within the first and second apertures 74, 76 about the seals 92 during vibrations without permitting metal-to-metal contact between the damper 78 and the torque frame 68 or the flex support 72.

    [0026] The damper 78 includes a cavity 88 that extends along its axial length between openings 90 provided at each end 80. The cavity 88 provides a viscous damping chamber. One or more orifices 94 are provided in the neck 82, for example, and are in fluid communication with the cavity 88. The orifices 94 permit an oil-mist in the gear compartment 96 to enter the cavity 88. Any oil collecting in the cavity 88 may drain through the orifices 94. The volume of the cavity 88 and the size, number and configuration of the orifices 94 are configured to damp a vibrational input from the geared architecture 48.

    [0027] Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.


    Claims

    1. A fan drive gear system for a gas turbine engine comprising:

    first and second members (68, 72) spaced apart from one another at a location;

    a gear train (48) supported by the first member (68); and

    a damper (78) provided between the first member (68) and the second member (72) at the location, wherein the first and second members (68, 72) respectively include first and second apertures (74, 76) aligned with one another in an axial direction, the damper (78) extending between and received in the first and second apertures (74, 76);

    wherein the damper (78) is a tube (79) having opposing ends (80) each supporting a seal (92), each seal (92) engaging a respective first and second aperture (74, 76).


     
    2. The fan drive gear system according to claim 1, wherein the first member (68) is a torque frame (68), the second member (72) is a flex support (72) having a bellow, and the flex support (72) is grounded to a static structure (36).
     
    3. The fan drive gear system according to claim 1 or 2, wherein the torque frame (68) and flex support (72) are secured to one another by fasteners (73) in an area spaced radially inward from the location.
     
    4. The fan drive gear system according to claim 3, wherein multiple dampers (78) are arranged circumferentially between the torque frame (68) and the flex support (72), and the bellow is provided between the fasteners (73) and the dampers (78).
     
    5. The fan drive gear system according to any preceding claim, wherein the torque frame (68) supports a carrier (66) to which star gears (62) are mounted, a sun gear (60) is arranged centrally relative to and intermeshing with the star gears (62), and a ring gear (64) circumscribing and intermeshing with the star gears (62).
     
    6. The fan drive gear system according to claim 5, further comprising a fan (42) coupled to the ring gear (64), and a low speed spool (30) coupled to the sun gear (60).
     
    7. The fan drive gear system according to any preceding claim, wherein the tube (79) provides a cavity (88), and an orifice (94) is provided in the tube (79) in fluid communication with the cavity (88), the cavity (88) providing a viscous damping chamber between the first and second members (68, 72).
     
    8. The fan drive gear system according to claim 7, wherein at least one of the gear train (48) and the second member (72) is configured to produce a vibrational input, and the orifice (94) and viscous damping chamber is configured to damp the vibrational input.
     
    9. The fan drive gear system according to any preceding claim, wherein each end (80) includes an annular groove (84) receiving a respective seal (92), and lateral sides (86) are provided on each end (80) with the respective end's annular groove (84) provided between the lateral sides (86), the lateral sides (86) providing annular tapers extending radially inward away from the respective end's annular groove (84) and configured to permit articulation of the damper relative to the first and second members (68, 72).
     
    10. The fan drive gear system according to claim 9, wherein the tube (79) includes a neck (82) arranged between ends (80) and having a diameter that is smaller than a diameter of the ends (80).
     


    Ansprüche

    1. Lüfterantriebssystem für einen Gasturbinenmotor, umfassend:

    ein erstes und zweites Element (68, 72), die an einer Stelle voneinander beabstandet sind;

    einen Getriebezug (48), der durch das erste Element (68) abgestützt ist; und

    einen Dämpfer (78), der zwischen dem ersten Element (68) und dem zweiten Element (72) an der Stelle bereitgestellt ist, wobei das erste und zweite Element (68, 72) eine erste bzw. zweite Aussparung (74, 76) beinhalten, die miteinander in einer axialen Richtung fluchten, wobei sich der Dämpfer (78) zwischen der ersten und zweiten Aussparung (74, 76) erstreckt und darin aufgenommen ist;

    wobei der Dämpfer (78) ein Rohr (79) ist, das entgegengesetzte Enden (80) aufweist, die jeweils eine Dichtung (92) abstützen, wobei jede Dichtung (92) eine jeweilige erste und zweite Aussparung (74, 76) in Eingriff nimmt.


     
    2. Lüfterantriebssystem nach Anspruch 1, wobei das erste Element (68) ein Drehmomentrahmen (68) ist, das zweite Element (72) eine Flexstütze (72) ist, die einen Balg aufweist, und die Flexstütze (72) an einer statischen Struktur (36) geerdet ist.
     
    3. Lüfterantriebssystem nach Anspruch 1 oder 2, wobei der Drehmomentrahmen (68) und die Flexstütze (72) in einem radial nach innen von der Stelle beabstandeten Bereich durch Befestigungselemente (73) aneinander gesichert sind.
     
    4. Lüfterantriebssystem nach Anspruch 3, wobei mehrere Dämpfer (78) umlaufend zwischen dem Drehmomentrahmen (68) und der Flexstütze (72) angeordnet sind und der Balg zwischen den Befestigungselementen (73) und den Dämpfern (78) bereitgestellt ist.
     
    5. Lüfterantriebssystem nach einem der vorhergehenden Ansprüche, wobei der Drehmomentrahmen (68) einen Träger (66) abstützt, an dem Sternräder (62) montiert sind, ein Sonnenrad (60) zentral in Bezug auf die Sternräder (62) angeordnet ist und mit diesen kämmt und ein Hohlrad (64) die Sternräder (62) umschreibt und mit diesen kämmt.
     
    6. Lüfterantriebssystem nach Anspruch 5, ferner umfassend einen Lüfter (42), der an das Hohlrad (64) gekoppelt ist, und eine Welle (30) mit niedriger Drehzahl, die an das Sonnenrad (60) gekoppelt ist.
     
    7. Lüfterantriebssystem nach einem der vorhergehenden Ansprüche, wobei das Rohr (79) einen Hohlraum (88) bereitstellt und ein Durchlass (94) in dem Rohr (79) in Fluidkommunikation mit dem Hohlraum (88) bereitgestellt ist, wobei der Hohlraum (88) eine viskose Dämpfungskammer zwischen dem ersten und zweiten Element (68, 72) bereitstellt.
     
    8. Lüfterantriebssystem nach Anspruch 7, wobei mindestens eines des Getriebezugs (48) und des zweiten Elements (72) dazu konfiguriert ist, eine Schwingungseingabe zu erzeugen, und der Durchlass (94) und die viskose Dämpfungskammer dazu konfiguriert sind, die Schwingungseingabe zu dämpfen.
     
    9. Lüfterantriebssystem nach einem der vorhergehenden Ansprüche, wobei jedes Ende (80) eine ringförmige Nut (84) beinhaltet, die eine jeweilige Dichtung (92) aufnimmt, und laterale Seiten (86) an jedem Ende (80) bereitgestellt sind, wobei die ringförmige Nut (84) des jeweiligen Endes zwischen den lateralen Seiten (86) bereitgestellt ist, wobei die lateralen Seiten (86) ringförmige Abschrägungen bereitstellen, die sich radial nach innen von der ringförmigen Nut (84) des jeweiligen Endes weg erstrecken und dazu konfiguriert sind, Gelenkbildung des Dämpfers in Bezug auf das erste und zweite Element (68, 72) zuzulassen.
     
    10. Lüfterantriebssystem nach Anspruch 9, wobei das Rohr (79) einen Hals (82) beinhaltet, der zwischen Enden (80) angeordnet ist und einen Durchmesser aufweist, der kleiner als ein Durchmesser der Enden (80) ist.
     


    Revendications

    1. Système d'engrenage d'entraînement de ventilateur pour une turbine à gaz comprenant :

    des premier et second éléments (68, 72) espacés l'un de l'autre au niveau d'un emplacement ;

    un train d'engrenages (48) supporté par le premier élément (68) ; et

    un amortisseur (78) prévu entre le premier élément (68) et le second élément (72) au niveau de l'emplacement, dans lequel les premier et second éléments (68, 72) comportent respectivement des première et seconde ouvertures (74, 76) alignées l'une avec l'autre dans une direction axiale, l'amortisseur (78) s'étendant entre et étant reçu dans les première et seconde ouvertures (74, 76) ;

    dans lequel l'amortisseur (78) est un tube (79) ayant des extrémités opposées (80) supportant chacune un joint (92), chaque joint (92) venant en prise avec une première et une seconde ouvertures respectives (74, 76).


     
    2. Système d'engrenage d'entraînement de ventilateur selon la revendication 1, dans lequel le premier élément (68) est un cadre de couple (68), le second élément (72) est un support flexible (72) ayant un soufflet, et le support flexible (72) est mis à la terre sur une structure statique (36).
     
    3. Système d'engrenage d'entraînement de ventilateur selon la revendication 1 ou 2, dans lequel le cadre de couple (68) et le support flexible (72) sont fixés l'un à l'autre par des attaches (73) dans une zone espacée radialement vers l'intérieur par rapport à l'emplacement.
     
    4. Système d'engrenage d'entraînement de ventilateur selon la revendication 3, dans lequel plusieurs amortisseurs (78) sont agencés circonférentiellement entre le cadre de couple (68) et le support flexible (72), et le soufflet est prévu entre les attaches (73) et les amortisseurs (78).
     
    5. Système d'engrenage d'entraînement de ventilateur selon une quelconque revendication précédente, dans lequel le cadre de couple (68) supporte un support (66) sur lequel des engrenages en étoile (62) sont montés, un planétaire (60) est agencé au centre par rapport aux engrenages en étoile (62) et s'engrenant avec ceux-ci, et une couronne dentée (64) circonscrivant et s'engrenant avec les engrenages en étoile (62).
     
    6. Système d'engrenage d'entraînement de ventilateur selon la revendication 5, comprenant en outre un ventilateur (42) couplé à la couronne dentée (64) et une bobine à faible vitesse (30) couplée au planétaire (60).
     
    7. Système d'engrenage d'entraînement de ventilateur selon une quelconque revendication précédente, dans lequel le tube (79) fournit une cavité (88), et un orifice (94) est prévu dans le tube (79) en communication fluidique avec la cavité (88), la cavité (88) fournissant une chambre d'amortissement visqueux entre les premier et second éléments (68, 72).
     
    8. Système d'engrenage d'entraînement de ventilateur selon la revendication 7, dans lequel au moins l'un du train d'engrenages (48) et du second élément (72) est conçu pour produire une entrée vibratoire, et l'orifice (94) et la chambre d'amortissement visqueux sont conçus pour amortir l'entrée vibratoire.
     
    9. Système d'engrenage d'entraînement de ventilateur selon une quelconque revendication précédente, dans lequel chaque extrémité (80) comporte une rainure annulaire (84) recevant un joint respectif (92), et des côtés latéraux (86) sont prévus sur chaque extrémité (80), la rainure annulaire (84) de l'extrémité respective étant prévue entre les côtés latéraux (86), les côtés latéraux (86) fournissant des cônes annulaires s'étendant radialement vers l'intérieur à l'écart de la rainure annulaire (84) de l'extrémité respective et conçus pour permettre l'articulation de l'amortisseur par rapport aux premier et second éléments (68, 72).
     
    10. Système d'engrenage d'entraînement de ventilateur selon la revendication 9, dans lequel le tube (79) comporte un col (82) agencé entre des extrémités (80) et ayant un diamètre qui est inférieur à un diamètre des extrémités (80).
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description