(19)
(11)EP 2 551 494 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
10.06.2020 Bulletin 2020/24

(21)Application number: 12178472.2

(22)Date of filing:  30.07.2012
(51)International Patent Classification (IPC): 
F02C 7/36(2006.01)

(54)

Motor-generator and prime mover gearing assembly

Motor-Generator und Antriebsmaschine-Getriebebaugruppe

Ensemble engrenage de moteur-générateur et moteur d'entraînement


(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: 28.07.2011 US 201113192526

(43)Date of publication of application:
30.01.2013 Bulletin 2013/05

(73)Proprietor: Hamilton Sundstrand Corporation
Windsor Locks, CT 06096-1010 (US)

(72)Inventors:
  • Lemmers, Glenn C. Jr.
    Loves Park, IL Illinois 61111 (US)
  • Behling, David S.
    Belvidere, IL Illinois 61008 (US)

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


(56)References cited: : 
US-A- 3 722 324
US-A1- 2007 130 959
US-A- 5 028 803
  
      
    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 generally to a gearing assembly that rotatably couples a prime mover and a motor-generator.

    [0002] Prime movers, such as turbomachines, are known. A typical turbomachine includes a fan section, a compression section, a combustor section, and a turbine section. Turbomachines have at least one rotor in the compression section. The rotor must be accelerated to a relatively high rotational speed until the rotor is rotating fast enough to sustain operation of the turbomachine.

    [0003] A motor-generator, separate from the turbomachine, is used as a motor to rotate the rotor during start-up of the turbomachine. After the turbomachine is self-sustaining, the motor-generator is used as a generator and driven by the turbomachine.

    [0004] The rotational speeds of prime movers may be different than the optimal speed of the motor-generator. Also, the rotational speeds vary considerably during operation, and it is desirable to provide the motor-generator with a rotational input that is relatively consistent. Hydro-mechanical transmissions are thus used to step-up or step-down rotation between the prime mover and the motor-generator. An exemplary arrangement is disclosed in US5028803. The size and weight of the hydro-mechanical transmissions must increase to accommodate larger ranges of rotational speeds.

    SUMMARY



    [0005] The present invention provides a prime mover and motor-generator gearing arrangement, according to claim 1, comprising: a hydro-mechanical transmission having a differential and a hydraulic pump; and a motor-generator arranged to be rotatably driven by the hydro-mechanical transmission; characterised by a mechanical transmission arranged to be rotatably driven by a prime mover at a first rotational speed, the mechanical transmission being selectively adjustable to rotatably drive the hydraulic pump at the first rotational speed or a second rotational speed different from the first rotational speed, wherein the mechanical transmission is driven by a low-pressure spool of the prime mover, and wherein the prime mover is a turbomachine.

    [0006] The present invention also provides a method, according to claim 9, of driving a motor-generator with a prime mover, comprising: driving a mechanical transmission with an input from a prime mover, the input rotating at a first rotational speed, wherein the prime mover is a low-pressure spool of a turbomachine; driving a hydraulic pump with a first output from the mechanical transmission, the first output rotating at a second rotational speed; driving the motor-generator with a second output from the hydraulic pump, wherein the second output is provided to a differential that directly drives the motor-generator; and selectively adjusting the mechanical transmission so that the first rotational speed is different from the second rotational speed.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0007] These and other features of the disclosed examples can be best understood from the following specification and drawings, the following of which is a brief description:

    Figure 1 shows schematic view of an example turbomachine, motor-generator, and gearing arrangement.

    Figure 2 shows a more detailed view of the Figure 1 gearing arrangement.

    Figure 3 shows a graph depicting example rotational speed relationships when utilizing the Figure 1 gearing arrangement.

    Figure 4 shows another example gearing arrangement suitable for use with the Figure 1 turbomachine and motor-generator.


    DETAILED DESCRIPTION



    [0008] Referring to Figures 1 and 2, an example gas turbine engine 10 is used to propel an aircraft. The gas turbine engine 10 is an example type of turbomachine, which is an example type of prime mover.

    [0009] The gas turbine engine 10 is circumferentially disposed about an axis X. The gas turbine engine 10 includes a fan section 14, a low-pressure compressor section 16, a high-pressure compressor section 18, a combustion section 20, a high-pressure turbine section 22, and a low-pressure turbine section 24. Other example turbomachines may include more or fewer sections.

    [0010] During operation, air is compressed in the low-pressure compressor section 16 and the high-pressure compressor section 18. The compressed air is then mixed with fuel and burned in the combustion section 20. The products of combustion are expanded across the high-pressure turbine section 22 and the low-pressure turbine section 24.

    [0011] The low-pressure compressor section 16 includes a rotor 26. The high-pressure compressor section 18 includes a rotor 28. The example rotors 26 and 28 include alternating rows of rotating airfoils or rotating blades and static airfoils or static blades.

    [0012] The high-pressure turbine section 22 includes a rotor 30. The low-pressure turbine section 24 includes a rotor 32. The rotors 30 and 32 are configured to rotate about the axis X in response to expansion across the high-pressure turbine section 22 and the low-pressure turbine section 24. The example rotors 30 and 32 include alternating rows of rotatable airfoils or rotatable blades and static airfoils or static blades.

    [0013] The rotor 30 is coupled to the rotor 28 through a high-pressure spool 34. The rotor 32 is coupled to the rotor 26 through a low-pressure spool 36. Thus, rotation of the rotors 30 and 32 rotates the rotors 28 and 26, which drives compression in the high-pressure compressor section 18 and the low-pressure compressor section 16, respectively. During operation of the gas turbine engine 10, the low-pressure spool 36 rotates across a greater range of rotational speeds than the high-pressure spool 34.

    [0014] Although the examples of a prime mover in this disclosure are described with reference to the gas turbine engine 10 that has a two-spool architecture, the examples are not limited to such architectures. That is, other types of turbomachines, and gas turbine engines having other architectures, such as a single-spool axial design, a three-spool axial design, may be used, as well as other prime movers, such as a piston engine, wankel engine, etc. There are various arrangements having prime movers that could benefit from the examples disclosed herein.

    [0015] In this example, the low-pressure spool 36 drives a motor-generator 50 when the motor-generator 50 is operating in a generator mode. The low-pressure spool 36 may drive the motor-generator 50 instead of, or in addition to, the high-pressure spool 34. When operating in the generator mode, the motor-generator 50 provides electrical power to various loads on the aircraft. The motor-generator 50 is typically required to provide power at a relatively constant frequency, or to ensure that the delivered power varies within a range of frequencies, such as 360-800 Hertz.

    [0016] The rotational speed of the low-pressure spool 36 varies considerably during operation of the gas turbine engine 10. The range of potential rotational speeds for the low-pressure spool 36 is greater than the range of potential speeds for the high-pressure spool 34. A gearing arrangement 52 accommodates the variation in rotational speeds from the low-pressure spool 36 and rotatably drives the motor-generator 50. In the prior art, the high-pressure spool 34 is typically used to drive the motor-generator 50.

    [0017] The example gearing arrangement 52 includes a hydro-mechanical transmission 54 and a mechanical transmission 56 separate from the hydro-mechanical transmission 54. The hydro-mechanical transmission 54 is constantly variable and includes a hydraulic pump 58 and a differential 66.

    [0018] In this example, the mechanical transmission 56 is configured to be selectively adjusted between a first position and a second position. In the first position, the mechanical transmission 56 rotates the differential 66 at the same speed as the low-pressure spool 36. In the second position, the mechanical transmission 56 rotates the differential 66 faster than the low-pressure spool 36. The example mechanical transmission 56 is a two-speed transmission. In other examples, the mechanical transmission 56 may adjust between three-speeds, or even more speeds.

    [0019] In one specific example, when the mechanical transmission 56 is in the first position, the differential 66 is rotated at 4,000 rpm when the low-pressure spool 36 rotates at 2,000 rpm. In this specific example, when the mechanical transmission 56 is in the second position, the differential 66 rotates at 4,000 rpm when the low-pressure spool 36 rotates at 4,000 rpm. The hydraulic pump 58 may further adjust the rotational speed. The hydraulic pump 58 rotates the motor-generator 50 through the differential 66.

    [0020] The example mechanical transmission 56 receives a rotational input from the low-pressure spool 36 through an input 70, which is an input shaft in this example. In one example, the rotational speed of the input 70 can vary during operation of the gas turbine engine 10 between a high speed that is five times greater than a low speed. For example, during operation of the gas turbine engine 10, the input 70 may rotate at 5,000 rpm at a high end and 1,000 rpm at a low end.

    [0021] The input 70 is directly engaged with the mechanical transmission 56 in this example. The mechanical transmission 56 then provides a rotational output via an output 72, which is also directly engaged with the mechanical transmission 56. The output 72 is a differential ring gear in this example.

    [0022] The example mechanical transmission 56 moves from a position where the output 72 rotates at the same speed as the input 70, and another position where the output 72 rotates twice for every single rotation of the input 70.

    [0023] The example mechanical transmission 56 includes a sunless differential gearing arrangement. The example mechanical transmission 56 is similar in design to the differential 66. A person having skill in this art and the benefit of this disclosure would understand how to design other types of mechanical transmissions movable between a position where the input and output rotate at the same speed, and a second position where the output rotates twice as fast as the input.

    [0024] The mechanical transmission 56 is connected to a controller 74. During operation of the gas turbine engine 10, the controller 74 initiates movement of the mechanical transmission 56 between the first position and the second position depending on the rotational speed of the low-pressure spool 36. The controller 74 may monitor the rotational speed of the low-pressure spool 36 to determine when to initiate movement between the first position and the second position. The controller 74 may automatically initiate movement, or may require a manual input, such as a switch.

    [0025] For example, referring to Figure 3 with continuing reference to Figures 1 and 2, the controller 74 may maintain the mechanical transmission 56 in the first position as the rotational speed of the low-pressure spool 36 increases from about 20% to 45% of the total potential speed of the low-pressure spool 36 along a path 78. In this example, 20% of the total potential speed is about 2,000 rpm and 45% of the total potential speed is about 4,000 rpm. When the low-pressure spool 36 reaches 45% of its total potential speed, the controller 74 moves the mechanical transmission 56 to the second position where the input 70 rotates together with the output 72. Other examples may move the mechanical transmission to a third position.

    [0026] In this example, the output 72 rotates the differential 66, which then provides a rotational input to the hydraulic pump 58. The hydraulic pump 58 further adjusts the rotational speeds to ensure that the motor-generator 50 provides a relatively consistent output. The hydraulic pump 58 rotatably drives the motor-generator 50 through the differential 66.

    [0027] Notably, in this example, the hydraulic pump 58 always receives an input that is greater than 4,000 rpm, even when the low-pressure spool 36 is rotating at a speed slower than 4,000 rpm. The mechanical transmission 56, in such an example, ensures that the rotational speed from the differential 66 is maintained above 4,000 rpm.

    [0028] In other examples, the hydraulic pump 58 receives an input rotating at 4,000 rpm or less. The input speed is optimized for the hydraulic pump 58.

    [0029] Referring to Figure 4 with continuing reference to Figure 1, another example gearing arrangement 152 includes a mechanical transmission 156, a differential 166, and a hydraulic pump 158. The numbering used in Figure 4 corresponds to the numbering in Figure 3 with a preappended "1."

    [0030] In this example, an input 170 is provided to the mechanical transmission by the differential 166. The differential 166 is rotated by a shaft 80 coupled to the low-pressure spool 36. The mechanical transmission 156 then is selectively moved between two positions to rotate the hydraulic pump 158 at the desired speed. A controller 174 may be used to control the movement of the mechanical transmission 156 between the first position and the second position.

    [0031] An output 172, in this example, is an output shaft extending directly from the mechanical transmission 156 to the hydraulic pump 158. The output 172 rotates the hydraulic pump 158. The hydraulic pump 158 then rotates the motor-generator 150 through the differential 166.

    [0032] Features of the disclosed examples include a gearing arrangement capable of receiving an input from a low-pressure spool of a turbomachine and providing rotational input to a motor-generator.

    [0033] 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 the scope of the invention.


    Claims

    1. A prime mover and motor-generator gearing arrangement (52;152) comprising:

    a hydro-mechanical transmission (54;154) having a differential (66;166) and a hydraulic pump (58;158); and

    a motor-generator (50;150) arranged to be rotatably driven by the hydro-mechanical transmission;

    characterised by a mechanical transmission (56;156) arranged to be rotatably driven by a prime mover (10) at a first rotational speed, the mechanical transmission being selectively adjustable to rotatably drive the hydraulic pump at the first rotational speed or a second rotational speed different from the first rotational speed, wherein the mechanical transmission is driven by a low-pressure spool (36) of the prime mover, and wherein the prime mover is a turbomachine (10).


     
    2. The prime mover and motor-generator gearing arrangement of claim 1, wherein the first rotational speed varies between a highest speed and a lowest speed, the highest speed being at least five times greater than the lowest speed.
     
    3. The prime mover and motor-generator gearing arrangement of any preceding claim, wherein the mechanical transmission is a two-speed transmission.
     
    4. The prime mover and motor-generator gearing arrangement of any preceding claim, wherein the mechanical transmission comprises a sunless differential.
     
    5. The prime mover and motor-generator gearing arrangement of any preceding claim, wherein an input shaft extends from the turbomachine directly to the mechanical transmission (56).
     
    6. The prime mover and motor-generator gearing arrangement of any preceding claim, wherein the mechanical transmission is arranged to rotatably drive the differential (66) that is arranged to rotate the hydraulic pump (58).
     
    7. The prime mover and motor-generator gearing arrangement of any one of claims 1 to 4, wherein the mechanical transmission (156) rotatably couples the differential (166) to the hydraulic pump (158).
     
    8. The prime mover and motor-generator gearing arrangement of any preceding claim, wherein the motor-generator is a narrow band variable frequency motor-generator having an output between 360-800 Hertz.
     
    9. A method of driving a motor-generator (50;150) with a prime mover (10), comprising:

    driving a mechanical transmission (56;156) with an input from a prime mover, the input rotating at a first rotational speed, wherein the prime mover is a low-pressure spool of a turbomachine,

    driving a hydraulic pump (58;158) with a first output from the mechanical transmission, the first output rotating at a second rotational speed;

    driving the motor-generator (50;150) with a second output from the hydraulic pump, wherein the second output is provided to a differential (66, 166) that directly drives the motor-generator; and

    selectively adjusting the mechanical transmission so that the first rotational speed is different from the second rotational speed.


     
    10. The method of claim 9, wherein the first output is provided to the differential (66) that directly drives the hydraulic pump (58).
     
    11. The method of claim 9, wherein the first output directly drives the hydraulic pump (158).
     


    Ansprüche

    1. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung (52;152), umfassend:

    ein hydromechanisches Getriebe (54;154) mit einem Differential (66;166) und einer Hydraulikpumpe (58;158); und

    einen Motor-Generator (50;150), der so angeordnet ist, dass er drehbar durch das hydromechanische Getriebe angetrieben wird;

    gekennzeichnet durch ein mechanisches Getriebe (56;156), das so angeordnet ist, dass es durch eine Antriebsmaschine (10) drehbar mit einer ersten Drehzahl angetrieben wird, wobei das mechanische Getriebe selektiv so einstellbar ist, dass es die Hydraulikpumpe drehbar mit der ersten Drehzahl oder einer zweiten Drehzahl antreibt, die sich von der ersten Drehzahl unterscheidet, wobei das mechanische Getriebe durch eine Niederdruckspule (36) der Antriebsmaschine angetrieben wird, und wobei es sich bei der Antriebsmaschine um eine Turbomaschine (10) handelt.


     
    2. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach Anspruch 1, wobei die erste Drehzahl zwischen einer höchsten Drehzahl und einer niedrigsten Drehzahl variiert, wobei die höchste Drehzahl mindestens fünfmal größer ist als die niedrigste Drehzahl.
     
    3. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der vorhergehenden Ansprüche, wobei es sich bei dem mechanischen Getriebe um ein Zweigang-Getriebe handelt.
     
    4. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der vorhergehenden Ansprüche, wobei das mechanische Getriebe ein sonnenradloses Differential umfasst.
     
    5. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der vorhergehenden Ansprüche, wobei sich eine Eingangswelle von der Turbomaschine direkt zu dem mechanischen Getriebe (56) erstreckt.
     
    6. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der vorhergehenden Ansprüche, wobei das mechanische Getriebe so angeordnet ist, dass es drehbar das Differential (66) antreibt, welches so angeordnet ist, dass es die Hydraulikpumpe (58) dreht.
     
    7. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der Ansprüche 1 bis 4, wobei das mechanische Getriebe (156) das Differential (166) drehbar an die Hydraulikpumpe (158) koppelt.
     
    8. Antriebsmaschinen- und Motor-Generator-Getriebeanordnung nach einem der vorhergehenden Ansprüche, wobei es sich bei dem Motor-Generator um einen Schmalband-Motorgenerator mit variabler Frequenz handelt, der eine Ausgabe zwischen 360-800 Hertz aufweist.
     
    9. Verfahren zum Antreiben eines Motor-Generators (50;150) mit einer Antriebsmaschine (10), umfassend:

    Antreiben eines mechanischen Getriebes (56;156) mit einem Eingang von einer Antriebsmaschine, wobei sich der Eingang mit einer ersten Drehzahl dreht, wobei es sich bei der Antriebsmaschine um eine Niederdruckspule einer Turbomaschine handelt;

    Antreiben einer Hydraulikpumpe (58;158) mit einem ersten Ausgang von dem mechanischen Getriebe, wobei sich der Ausgang mit einer zweiten Drehzahl dreht;

    Antreiben des Motor-Generators (50;150) mit einem zweiten Ausgang von der Hydraulikpumpe, wobei der zweite Ausgang einem Differential (66;166) bereitgestellt wird, das den Motor-Generator direkt antreibt; und

    selektives Einstellen des mechanischen Getriebes, sodass sich die erste Drehzahl von der zweiten Drehzahl unterscheidet.


     
    10. Verfahren nach Anspruch 9, wobei der erste Ausgang dem Differential (66) bereitgestellt wird, das die Hydraulikpumpe (58) direkt antreibt.
     
    11. Verfahren nach Anspruch 9, wobei der erste Ausgang die Hydraulikpumpe (158) direkt antreibt.
     


    Revendications

    1. Ensemble engrenage de moteur d'entraînement et de moteur-générateur (52 ; 152) comprenant :

    une transmission hydromécanique (54 ; 154) ayant un différentiel (66 ; 166) et une pompe hydraulique (58 ; 158) ; et

    un moteur-générateur (50 ; 150) agencé pour être entraîné en rotation par la transmission hydromécanique ;

    caractérisé par une transmission mécanique (56 ; 156) agencée pour être entraînée en rotation par un moteur d'entraînement (10) à une première vitesse de rotation, la transmission mécanique étant réglable sélectivement pour entraîner en rotation la pompe hydraulique à la première vitesse de rotation ou à une seconde vitesse de rotation différente de la première vitesse de rotation, dans lequel la transmission mécanique est entraînée par une bobine basse pression (36) du moteur d'entraînement, et dans lequel le moteur d'entraînement est une turbomachine (10).


     
    2. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon la revendication 1, dans lequel la première vitesse de rotation varie entre une vitesse la plus élevée et une vitesse la plus faible, la vitesse la plus élevée étant au moins cinq fois supérieure à la vitesse la plus faible.
     
    3. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon une quelconque revendication précédente, dans lequel la transmission mécanique est une transmission à deux vitesses.
     
    4. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon une quelconque revendication précédente, dans lequel la transmission mécanique comprend un différentiel sans roue solaire.
     
    5. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon une quelconque revendication précédente, dans lequel un arbre d'entrée s'étend depuis la turbomachine directement vers la transmission mécanique (56).
     
    6. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon une quelconque revendication précédente, dans lequel la transmission mécanique est agencée pour entraîner en rotation le différentiel (66) qui est agencé pour faire tourner la pompe hydraulique (58).
     
    7. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon l'une quelconque des revendications 1 à 4, dans lequel la transmission mécanique (156) couple de manière rotative le différentiel (166) à la pompe hydraulique (158).
     
    8. Ensemble engrenage de moteur d'entraînement et de moteur-générateur selon une quelconque revendication précédente, dans lequel le moteur-générateur est un moteur-générateur de fréquence variable à bande étroite ayant une sortie comprise entre 360 et 800 Hertz.
     
    9. Procédé d'entraînement d'un moteur-générateur (50 ; 150) avec un moteur d'entraînement (10), comprenant :

    l'entraînement d'une transmission mécanique (56 ; 156) avec une entrée d'un moteur d'entraînement, l'entrée tournant à une première vitesse de rotation, dans lequel le moteur d'entraînement est une bobine basse pression d'une turbomachine ;

    l'entraînement d'une pompe hydraulique (58 ; 158) avec une première sortie de la transmission mécanique, la première sortie tournant à une seconde vitesse de rotation ;

    l'entraînement du moteur-générateur (50 ; 150) avec une seconde sortie de la pompe hydraulique, dans lequel la seconde sortie reçoit un différentiel (66, 166) qui entraîne directement le moteur-générateur ; et

    le réglage sélectif de la transmission mécanique de sorte que la première vitesse de rotation est différente de la seconde vitesse de rotation.


     
    10. Procédé selon la revendication 9, dans lequel la première sortie reçoit le différentiel (66) qui entraîne directement la pompe hydraulique (58).
     
    11. Procédé selon la revendication 9, dans lequel la première sortie entraîne directement la pompe hydraulique (158).
     




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    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