(19)
(11)EP 0 277 906 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
17.06.1992 Bulletin 1992/25

(21)Application number: 88630016.9

(22)Date of filing:  01.02.1988
(51)International Patent Classification (IPC)5F01D 5/02, F01D 5/28, F01D 7/00

(54)

Composite disk for supporting fan blades

Rotorscheibe aus Verbundwerkstoff

Disque en matériau composé pour le rotor d'une soufflante


(84)Designated Contracting States:
DE FR GB

(30)Priority: 02.02.1987 US 10237

(43)Date of publication of application:
10.08.1988 Bulletin 1988/32

(73)Proprietor: UNITED TECHNOLOGIES CORPORATION
Hartford, CT 06101 (US)

(72)Inventor:
  • Dennison, William T.
    Vernon Connecticut 06066 (US)

(74)Representative: Weydert, Robert et al
Dennemeyer & Associates Sàrl P.O. Box 1502
1015 Luxembourg
1015 Luxembourg (LU)


(56)References cited: : 
AT-B- 232 635
FR-A- 2 340 448
US-A- 3 360 051
US-A- 3 687 569
DE-A- 3 538 599
GB-A- 1 385 968
US-A- 3 532 439
US-A- 4 021 142
  
      
    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


    [0001] This invention relates to a composite disk or ring assembly for supporting the fan blades on a high bypass turbine engine particularly where the fan is mounted outside and surrounding the engine core. The invention also concerns a method of making the composite disk or ring assembly.

    [0002] These disks or rings have been made generally of a metal which is machined to provide the circumferentially spaced bearing mountings in which the individual fan blade roots are supported for turning movement in adjusting the pitch of the blades. These metallic rings as disclosed e. g. in US-A-4,021,142 are necessarily heavy in order to carry the loading thereon during the operation of the fan. It is well known that weight reduction is desirable wherever possible in a aircraft engine and if a composite support ring can be made strong enough to carry the loading on the blades a substantial weight reduction will result with an inevitable significant reduction in the total weight of the engine.

    [0003] Thus, there is provided in accordance with the invention a ring assembly for the support of a row of fan blades for a bypass turbine engine, the blades being turnable on a radial axis for pitch changing, characterized in that said ring assembly comprises a composite ring of layers or plies of fibers, substantially the outer half of the ring having the fibers of the plies thereof generally arranged at 0° to the circumferential direction of the ring, substantially the inner half of the ring having the fibers of a portion of the plies arranged at 0°, said portion of the plies alternating with the remaining plies, said remaining plies comprising in part plies having the fibers thereof at 45° and plies having the fibers thereof at 90 degrees with respect to the circumferential direction of the ring, with additional plies of fibers arranged generally on the side surfaces of the ring and on the inner and outer surfaces and extending beyond the ring to form mounting flanges for the ring, said additional plies having the fibers thereof generally at substantially 45° to the circumferential direction of the ring, said composite ring having radial holes formed therein for the fan blades, and mounting bosses positioned in said holes to receive the blade roots.

    [0004] The method of making the ring assembly is characterized by wrapping the plies making up the inner and outer half of the ring about a support drum, curing the wrapped plies making up the inner and outer half of the ring under heat and pressure, machining the radial openings and the annular groove in the cured ring, applying the additional plies to the side surface and to the inner and outer surfaces of the ring and thereafter curing the additional plies.

    [0005] Advantageous features of the ring assembly are recited in the dependent claims 2 through 7.

    [0006] The foregoing and other features and advantages of the present invention will become more apparent from the following description of preferred embodiments and accompanying drawings, wherein:

    Fig. 1 is a sectional view of a completed ring assembly showing the blade root positioned therein and the mounting of the ring within the engine.

    Fig. 2 is a transverse sectional view of the portion of the ring.

    Fig. 3 is a view looking in the direction of the arrow 3 of Fig. 2 to show the position of the flanges on the support bosses.

    Fig. 4 is a sectional view of the ring structure before being machined.

    Fig. 5 is a sectional view of the ring after being machined.

    Fig. 6 is a sectional view of the ring after the additional plies have been added to the surfaces of the basic ring.



    [0007] As shown in Fig. 1, the ring 10, made of composite material, as will be described later, has the additional plies of fibers 12 on the inner surface 14 and other plies of fibers 16 on the portion of the outer surface 18 to the left of the groove 19 and on one side surface 20. The fibers 16 overlap with the plies of fibers 12 to form a flange 24 having an outwardly turned edge to form a radial flange 26 for attachment to a driving ring 27.

    [0008] At the other end of the ring there are additional plies 28 extending generally radially on the other side surface 30 of the basic ring and projecting radially inward of the ring to overlap with the mating portion 32 of the plies 12 to form the flange 34 for attachment to a support structure 36. Additional plies of fibers 38 on the portion of the outer surface 18 to the right of the groove 19 and extending radially inward therefrom abut against the radial plies 28. At their inner portion these plies form a part of the flange 34. From this set of plies of fibers 38 annular flanges 40 and 42 are formed to serve as sealing flanges cooperating with fixed seals 44 and 46.

    [0009] The ring 10 has radial holes or openings 48 formed therein to receive mounting bosses 50 each of which has a groove 51 in its inner surface to receive a row of ball bearings. Each boss has a flange 54 at its inner end and this flange is generally square to provide corners to receive bolts 56 therethrough which extend into the composite ring and hold the bosses in position thereon. Suitable spacers 58 are provided to fill the space between the flat flange and the cooperating curved inner surface of the ring to distribute the load on the boss over an extended portion of the ring. The ring also has the annular groove 19, above referred to, in its outer surface 18. This groove intersects the holes 48 and exposes the outer ends of the bosses 50. The surface 18 is in fact two spaced apart distinct surfaces on opposite sides of the annular groove as mentioned earlier.

    [0010] The fan blade 62 has a root 64 with an annular groove 66 thereon positioned in the supporting boss with the bearings 52 engaging said groove 66 as shown. The balls are trapped in position by a split clamping ring 68 engaging the outer end of the boss and shoulder 70 on the fan blade root 64 and this arrangement serves to hold the blade root securely in position. The ring assembly as above described is supported for rotation in surrounding relation to the engine structure by the support structure 36 extending generally inwardly from the attachment flange 34 and attached thereto. The end 73 of the support structure 36 opposite the flange 34 is mounted in a bearing 74 carried by a fixed support structure 76 integral with the surrounding engine casing.

    [0011] The blade root has an eccentrically projecting arm 78 at its inner end to provide for the attachment of a pitch control mechanism.

    [0012] In making the ring 10 the composite structure is built up of layers of plies of high strength fiber generally wrapped around a support drum. Substantially the inner half 10a of the composite ring is made up of about 40% of plies of fibers of graphite filaments arranged at 0° alternating with about 30% of 45° of fiberglass fibers arranged in plies and 30% of 90° fiberglass fibers also arranged in plies. The 0° means parallel to the circumferential direction and obviously 90° means the plies are parallel to the longitudinal axis of the ring. Similarly 45° fibers means at an angle midway between 0° and 90°.

    [0013] When this portion of the ring is completed the remaining outer half 10b of the ring is built up of wrapped layers of plies of graphite fibers all generally at 0° for circumferential strength and stiffness in the completed ring.

    [0014] This particular percentage of fibers is characteristic of one specific ring and variations may be utilized depending on the strength desired in certain different portions of the ring. However this particular arrangement has been found to be effective for one particular installation.

    [0015] After the plies of the ring have all been assembled the complete assemblage is cured by the usual curing procedures utilizing heat and pressure. The plies may have been pre-pregnated with a matrix material or the matrix material may be added at the start of the curing process. Either of these procedures is well known in the art and the techniques for completing the curing process in either event is also well known.

    [0016] The curing of this basic ring having been completed the several radial openings 48 are machined and the annular groove 19 is also machined to provide the partially completed structure of Fig. 5. It will be noted that the base of the groove 19 is close to the division between the outer 0° plies and the inner composite of different plies.

    [0017] After the ring has been machined the surrounding plies 12 on the inner surface and the plies 16 on the outer surface are positioned. The surface 18 is now two spaced surfaces 18 by reason of the intervening groove 19 and the plies do not extend over this groove. These plies are generally fiberglass and at 45° so that they may be shaped to conform to the outer surface 18 and the side surface 20 of the ring and also to form the flange 26. Also the plies 28 are mounted at the other side surface 30 of the ring and these plies are also generally fiberglass and with a 45° arrangement of the fibers. The other plies 38 are also added and shaped as above described to form the necessary flanges as shown in Fig. 1. After these plies have all been added and in the shape shown in the finished product the ring is again subjected to a curing to harden these additional plies and to form a completed ring or disk construction in which these added plies will be integral with and therefore essentially a part of the basic ring. It is understood that the manner and sequence of assembling the plies may be altered to satisfy individual manufacturing and production capabilities.

    [0018] Thereafter the bosses are mounted with the spacers 58 and the assemblage is then ready for the attachment of the fan blades. Since the assembly of these fan blades is not an essential part of the present invention it will not be described.


    Claims

    1. Ring assembly for the support of a row of fan blades for a bypass turbine engine, the blades being turnable on a radial axis for pitch changing, characterized in that said ring assembly comprises a composite ring of layers or plies of fibers,
       substantially the outer half (10b) of the ring (10) having the fibers of the plies thereof generally arranged at 0° to the circumferential direction of the ring (10),
       substantially the inner half (10a) of the ring (10) having the fibers of a portion of the plies arranged at 0°, said portion of the plies alternating with the remaining plies, said remaining plies comprising in part plies having the fibers thereof at 45° and plies having the fibers thereof at 90 degrees with respect to the circumferential direction of the ring (10),
       with additional plies of fibers (12,16,28,38) arranged generally on the side surfaces (20,30) of the ring (10) and on the inner and outer surfaces (14,18) and extending beyond the ring (10) to form mounting flanges (26, 34) for the ring (10), said additional plies (12,16,28,38) having the fibers thereof generally at substantially 45° to the circumferential direction of the ring (10),
       said composite ring (10) having radial holes (48) formed therein for the fan blades (62), and
       mounting bosses (50) positioned in said holes (48) to receive the blade roots (64).
     
    2. Ring assembly according to claim 1, characterized in that the fibers in the outer half (10b) are generally of graphite and a substantial part of the fibers in the inner half (10a) of the ring (10) are fiberglass.
     
    3. Ring assembly according to claim 2, characterized in that the fibers of the additional plies (12,16,28,38) are generally fiberglass.
     
    4. Ring assembly according to claim 1, characterized in that the mounting bosses (50) are flanged and with the flanges (54) at the inner side of the ring (10) and with bolts (56) securing the bosses (50) to the ring (10).
     
    5. Ring assembly according to claim 1, characterized in that a portion of the additional plies (38) are shaped to form seal flanges (40, 42) on the ring (10).
     
    6. Ring assembly according to claim 1, characterized in that the radial holes (48) in the ring (10) extend through the inner half (10a) of the ring (10) and intersect with an annular groove (19) extending radially inward from the outer surface (18) of the ring (10) to intersect said radial holes (48).
     
    7. Ring assembly according to claim 1, characterized in that the inner half (10a) of the ring (10) has the fibers of about 40 % of the plies arranged at 0°, the fibers of about 30% of the plies at 45° and the fibers of the remaining 30 % of the plies at 90 degrees with respect to the circumferential direction of the ring (10).
     
    8. Method of making the ring assembly of claim 1, characterized by:
       wrapping the plies making up the inner and outer half (10a,10b) of the ring (10) about a support drum,
       curing the wrapped plies making up the inner and outer half (10a,10b) of the ring (10) under heat and pressure,
       machining the radial openings (48) and the annular groove (19) in the cured ring,
       applying the additional plies (12,16,28,38) to the side surface (20,30) and to the inner and outer surfaces (14,18) of the ring (10) and thereafter curing the additional plies (12,16,28,38).
     


    Revendications

    1. Couronne destinée à supporter une série de pales de soufflante pour un turboréacteur à double flux, ces pales pouvant tourner autour d'un axe radial pour assurer une variation du pas, caractérisée en ce que la couronne est constituée par une couronne composite de couches ou nappes de fibres, les fibres des couches de pratiquement la moitié externe (10b) de la couronne (10) étant disposées d'une manière générale à 0° par rapport à la direction circonférentielle de la couronne (10), les fibres d'une partie des couches de pratiquement la moitié interne (10a) de la couronne (10) étant disposées à 0°, cette partie des couches alternant avec les couches restantes, ces couches restantes comprenant en partie des couches dont les fibres sont orientées à 45° et en partie des couches dont les fibres sont orientées à 90° par rapport à la direction circonférentielle de la couronne (10), des couches additionnelles de fibres (12,16,28,38) étant disposées d'une manière générale sur les surfaces latérales (20,30) de la couronne (10) et sur les surfaces interne et externe (14,18) et s'étendant au-delà de la couronne (10) afin de former des brides de montage (26,34) pour la couronne (10), les fibres de ces couches additionnelles (12,16,28,38) s'étendant d'une manière générale sensiblement à 45° par rapport à la direction circonférentielle de la couronne (10), la couronne composite (10) étant percée trous radiaux (48) pour les pales de soufflante (62), des montures en saillie (50) étant disposées dans les trous (48) afin de recevoir les pieds (64) des pales.
     
    2. Couronne suivant la revendication 1 caractérisée en ce que les fibres se trouvant dans la moitié externe (10b) sont généralement en graphite et une partie notable des fibres dans la moitié interne (10a) de la couronne (10) sont des fibres de verre.
     
    3. Couronne suivant la revendication 2 caractérisée en ce que les fibres des couches additionnelles (12,16,28,38) sont généralement des fibres de verre.
     
    4. Couronne suivant la revendication 1 caractérisée en ce que les montures en saillie (50) sont pourvues de brides (54) situées du côté interne de la couronne (10) et de vis (56) fixant les montures (50) à la couronne (10).
     
    5. Couronne suivant la revendication 1 caractérisée en ce qu'une partie des couches additionnelles (38) sont conformées de manière à constituer des brides de joint d'étanchéité (40,42) sur la couronne (10).
     
    6. Couronne suivant la revendication 1 caractérisée en ce que les trous radiaux (48) dans la couronne (10) s'étendent à travers la moitié interne (10a) de la couronne (10) et ils débouchent dans une gorge annulaire (19) s'étendant radialement vers l'intérieur à partir de la surface externe (18) de la couronne (10), pour recouper les trous radiaux (48).
     
    7. Couronne suivant la revendication 1 caractérisée en ce que dans la moitié interne (10a) de la couronne (10) les fibres d'environ 40% des couches sont disposées avec une orientation à 0°, les fibres d'environ 30% des couches sont disposées à 45° et les fibres des 30% restant des couches sont disposées à 90° par rapport à la direction circonférentielle de la couronne (10).
     
    8. Procédé de fabrication de la couronne suivant la revendication 1 caractérisé en ce qu'on enroule les couches formant les moitiés interne et externe (10a,10b) de la couronne (10) autour d'un mandrin support, on durcit les couches enroulées constituant les moitiés interne et externe (10a,10b) de la couronne (10) sous l'effet de la chaleur et de la pression, on usine les trous radiaux (48) et la gorge annulaire (19) dans la couronne durcie, et on applique les couches additionnelles (12,16,28,38) à la surface latérale (20,30) et aux surfaces interne et externe (14,18) de la couronne (10), après quoi on durcit les couches additionnelles (12,16,28,38).
     


    Ansprüche

    1. Ringvorrichtung zum Tragen eines Kranzes von Fan-Schaufeln für ein Mantelstromturbinentriebwerk, wobei die Schaufeln zur Schaufelverstellung um eine radiale Achse drehbar sind, dadurch gekennzeichnet, daß die Ringvorrichtung einen Verbundring aus Schichten oder Lagen von Fasern aufweist,
    wobei im wesentlichen die äußere Hälfte (10b) des Ringes (10) die Fasern der Lagen desselben insgesamt unter 0° gegen die Umfangsrichtung des Ringes (10) angeordnet hat, wobei im wesentlichen die innere Hälfte (10a) des Ringes (10) die Fasern eines Teils der Lagen unter 0° angeordnet hat, wobei dieser Teil der Lagen mit den übrigen Lagen abwechselt, wobei die übrigen Lagen zum Teil Lagen umfassen, die ihre Fasern unter 45° haben, und Lagen, die ihre Fasern unter 90° in bezug auf die Umfangsrichtung des Ringes (10) haben,
    wobei zusätzliche Lagen von Fasern (12, 16, 28, 38) insgesamt auf den Seitenoberflächen (20, 30) des Ringes (10) und auf der inneren und äußeren Oberfläche (14, 18) angeordnet sind und sich über den Ring (10) hinaus erstrecken, um Befestigungsflansche (26, 34) für den Ring (10) zu bilden, wobei die zusätzlichen Lagen (12, 16, 28, 38) ihre Fasern insgesamt im wesentlichen unter 45° zu der Umfangsrichtung des Ringes (10) haben,
    wobei in dem Verbundring (10) radiale Löcher (48) für die Fan-Schaufeln (62) gebildet sind, und
    Befestigungsbuchsen (50) in den Löchern (48) zum Aufnehmen der Schaufelfüße (64) angeordnet sind.
     
    2. Ringvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daS die Fasern in der äußeren Hälfte (10b) insgesamt aus Graphit bestehen und daß ein wesentlicher Teil der Fasern in der inneren Hälfte (10a) des Ringes (10) Glasfasern sind.
     
    3. Ringvorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die Fasern der zusätzlichen Lagen (12, 16, 28, 38) insgesamt aus Glasfasern bestehen.
     
    4. Ringvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Befestigungsbuchsen (50) mit Flansch versehen sind und sich die Flansche (54) auf der inneren Seite des Ringes (10) befinden und die Buchsen (50) mittels Schrauben (56) an dem Ring (10) befestigt sind.
     
    5. Ringvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß Teile der zusätzlichen Lagen (38) so geformt sind, daß sie Dichtflansche (40, 42) an dem Ring (10) bilden.
     
    6. Ringvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß sich die radialen Löcher (48) in dem Ring (10) durch die innere Hälfte (10a) des Ringes (10) erstrecken und eine ringförmige Nut (19) schneiden, welche sich von der äußeren Oberfläche (18) des Ringes (10) aus radial einwärts erstreckt, um die radialen Löcher (48) zu schneiden.
     
    7. Ringvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die innere Hälfte (10a) des Ringes (10) die Fasern von etwa 40% der Lagen unter 0° angeordnet hat, die Fasern von etwa 30% der Lagen unter 45° und die Fasern der übrigen 30% der Lagen unter 90 Grad in bezug auf die Umfangsrichtung des Ringes (10).
     
    8. Verfahren zum Herstellen der Ringvorrichtung nach Anspruch 1, gekennzeichnet durch:
    Herumwickeln der Lagen, aus denen die innere und äußere Hälfte (10a, 10b) des Ringes (10) aufgebaut ist, um eine Tragtrommel,
    Aushärten der herumgewickelten Lagen, aus denen die innere und äußere Hälfte (10a, 10b) des Ringes (10) bestehen, unter Wärme und Druck,
    spanabhebendes Bearbeiten der radialen Öffnungen (48) und der ringförmigen Nut (19) in dem ausgehärteten Ring,
    Auftragen der zusätzlichen Lagen (12, 16, 28, 38) auf die Seitenoberfläche (20, 30) und auf die innere und äußere Oberfläche (14, 18) des Ringes (10) und anschließendes Aushärten der zusätzlichen Lagen (12, 16, 28, 38).
     




    Drawing