工藝制造-31模壓成型工藝-19ep2634367a1

1、(19)TEPZZ 6467A_TEP 2 634 367A1(11)EUROPEAN PATENT APPLICATION(12)(43)(51) Int Cl.:F01D 5/14 (2006.01)Date of publication:04.09.2013 Bulletin 2013/36F01D 5/16 (2006.01)(21)Application number: 13156783.6(22)Date of filing: 26.02.2013(54)Method of applying liquid adhesive to a surface of a metallic fa

2、n blade(57)A method of forming a fan blade (62) includes(74) to form a plurality of rows (98) of adhesive (80) on the inner surface (86) of the cover (74). The method fur- ther includes the steps of applying the inner surface (88) of the cover (74) to a fan blade body (64) and curing the adhesive (8

3、0) to secure the cover (74) to the fan blade body (64).the steps of applying an adhesive (80) to an inner surface(86) of a cover (74) and moving a toothed instrument (94) along the inner surface (86) of the cover (74) to spread the adhesive (80) over the inner surface (86) of the coverPrinted by Jou

4、ve, 75001 PARIS (FR)EP 2 634 367 A1(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 TRDesignated Extension States:BA ME(30) Priority: 29.02.2012 US 201213408158(71) Applicant: United Technologies Corpora

5、tion Hartford, CT 06101 (US)(72) Inventors: Parkin, MichaelSouth Glastonbury, CT Connecticut 06073 (US) Hertel, Christopher J.Wethersfield, CT Connecticut 06109 (US)(74) Representative: Hull, James Edward DehnsSt. Brides House 10 Salisbury Square LondonEC4Y 8JD (GB)1EP 2 634 367 A12Descriptionclude

6、the step of moving a toothed instrument along an inner surface of a cover from a first edge of the inner surface of the cover to an opposing second edge of the inner surface of the cover.0011 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude the

7、 step of applying an inner surface of a cover to a fan blade body to spread rows of adhesive to form a layer of adhesive having a thickness.0012 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a layer of adhesive having a thickness of about0.0

8、05 inch (0.0127 cm) to about 0.015 inch (0.0381 cm). 0013 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude the step of dampening vibrations with a layer of adhesive.0014 In a further non-limiting embodiment of any of the forgoing method embodim

9、ents, the method may in- clude the step of curing an adhesive by employing a vac- uum.0015 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude the step of curing an adhesive by employing pres- sure.0016 Another method of forming a fan blade accord

10、- ing an exemplary aspect of the present disclosure in- cludes, among other things, the step of applying a ure- thane adhesive near a first edge of an inner surface of a cover made of aluminum or an aluminum alloy. The meth- od further includes the step of moving a toothed instru- ment along the inn

11、er surface of the cover from a first edge of the inner surface of the cover to an opposing second edge of the inner surface of the cover to spread the ad- hesive over the inner surface of the cover to create a plurality of rows of adhesive on the inner surface of the cover. The method further includ

12、es the steps of applying the inner surface of the cover to a fan blade body made of aluminum or aluminum alloy and curing the adhesive to secure the cover to the fan blade body.0017 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a fan blade b

13、ody having an inner surface including a plurality of cavities, and a low density filler is received in each of the plurality of cavities.0018 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a low density filler that is aluminum foam.0019 In a

14、further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude the step of applying an inner surface of a cover to a fan blade body to spread the rows of adhesive to form a layer of adhesive having a thickness.0020 In a further non-limiting embodiment of any of t

15、he forgoing method embodiments, the method may in- clude a layer of adhesive having a thickness of about0.005 inch (0.0127 cm) to about 0.015 inch (0.0381 cm).0021 In a further non-limiting embodiment of any ofBACKGROUND OF THE INVENTION0001 A gas turbine engine includes a fan section that drives ai

16、r along a bypass flowpath while a compressor section drives air along a core flowpath for compression and communication into a combustor section then ex- pansion through a turbine section.0002 Fan blades are commonly made of titanium or carbon fiber. Sheet adhesive films, for example epoxy films, ca

17、n be used to secure parts of the fan blade to- gether as they are strong, durable, easy to apply, and have a consistent weight and thickness. Urethane based adhesives can provide more damping ability than con- ventional epoxy based adhesives. However, urethane is not available as a film, but as a li

18、quid. When a liquid adhesive is applied to a surface and spread over a sur- face, unevenness and inconsistencies in the thickness of the adhesive can result.5101520SUMMARY OF THE INVENTION0003 A method of forming a fan blade according an exemplary aspect of the present disclosure includes, among oth

19、er things, the steps of applying an adhesive to an inner surface of a cover and moving a toothed in- strument along the inner surface of the cover to spread the adhesive over the inner surface of the cover to form a plurality of rows of adhesive on the inner surface of the cover. The method further

20、includes the steps of applying the inner surface of the cover to a fan blade body and curing the adhesive to secure the cover to the fan blade body.0004 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a cover made of aluminum or an aluminum al

21、loy. 0005 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a fan blade body made of aluminum or an aluminum alloy.0006 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude adhesive that is ure

22、thane.0007 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude a fan blade body having an inner surface including a plurality of cavities, and a low density filler is received in each of the plurality of cavities.0008 In a further non-limiting emb

23、odiment of any of the forgoing method embodiments, the method may in- clude a low density filler that is aluminum foam.0009 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in- clude the step of applying an adhesive to an inner surface of a cover near a

24、first edge of the cover.0010 In a further non-limiting embodiment of any of the forgoing method embodiments, the method may in-2530354045505523EP 2 634 367 A14the forgoing method embodiments, the method may in- clude the step of dampening vibrations with a layer of adhesive.0022 In a further non-lim

25、iting embodiment of any of the forgoing method embodiments, the method may in- clude the step of curing an adhesive by employing a vac- uum and pressure.0023 These and other features of the present inven- tion can be best understood from the following specifica- tion and drawings, the following of w

26、hich is a brief de- scription.38 at various locations may alternatively or additionally be provided.0029 The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42, a low pressure compressor 44 and a low pressure turbine 46. The inner shaft 40 is connected to the fan 42

27、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 com- pressor 52 and a high pressure turbine 54.0030 A combustor 56 is arranged between the high pressure compressor

28、 52 and the high pressure turbine 54.0031 A mid-turbine frame 58 of the engine static structure 36 is arranged generally between the high pres- sure turbine 54 and the low pressure turbine 46. The mid- turbine frame 58 further supports bearing systems 38 in the turbine section 28.0032 The inner shaf

29、t 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.0033 The core airflow C is compressed by the low pressure compressor 44, then the high pressure com- pressor 52, mixed and burned

30、 with fuel in the combustor 56, then expanded over the high pressure turbine 54 and low pressure turbine 46. The mid-turbine frame 58 in- cludes airfoils 60 which are in the core airflow path C. The turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in respo

31、nse to the expansion.0034 The engine 20 is in one example a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six (6:1) with an example embodiment being greater than ten (10:1). The geared architecture 48 is an epicyclic gear train (such as a

32、planetary gear system or other gear system) with a gear reduction ratio of greater than about 2.3 (2.3:1). The low pressure turbine 46 has a pressure ratio that is great- er than about five (5:1). The low pressure turbine 46 pres- sure ratio is pressure measured prior to inlet of low pres- sure turb

33、ine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. 0035 In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten (10:1), and the fan diameter is significantly larger than that of the low pres- sure compressor 44. The lo

34、w pressure turbine 46 has a pressure ratio that is greater than about five (5:1). The geared architecture 48 may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.5 (2.5: 1). It should be understood, however, that the

35、 above pa- rameters 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.0036 A significant amount of thrust is provided by thebypass flow B due to the high bypass ratio. The fa

36、n sec-510BRIEF DESCRIPTION OF THE DRAWINGS002415Figure 1 illustrates a schematic view of a gas turbine engine;Figure 2 illustrates an exploded view of a fan blade; Figure 3 illustrates an inner surface of a cover of a fan blade with an adhesive applied near an edge; Figure 4 illustrates the inner su

37、rface of the cover of the fan blade once the adhesive has been spread over the inner surface of the cover with a toothed instrument;Figure 5 illustrates a toothed trowel used to spread the adhesive over the inner surface of the cover; Figure 6 illustrates a layer of adhesive after the ap- plication

38、of the cover to a blade body; andFigure 7 illustrates a flowchart showing a method of attaching the cover to a blade body.202530DETAILED DESCRIPTION OF THE PREFERRED EM- BODIMENTS350025 Figure 1 schematically illustrates a gas turbine engine 20. The gas turbine engine 20 is disclosed herein as a two

39、-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.0026 Although depicted as a turbofan gas turbine en- gine in the

40、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 or geared turbofan architectures.0027 The fan section 22 drives air along a bypa

41、ss flowpath B while the compressor section 24 drives air along a core flowpath C for compression and communi- cation into the combustor section 26 then expansion through the turbine section 28.0028 The engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation a

42、bout an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems38. It should be understood that various bearing systems4045505535EP 2 634 367 A16tion 22 of the engine 20 is designed for a particular flight condition- typically cruise at about 0.8 Mach

43、 and about 35,000 feet (10,668 meters). The flight condition of 0.8 Mach and 35,000 feet (10,668 meters), with the engine at its best fuel consumption, also known as bucket cruise Thrust Specific Fuel Consumption (TSFC), is the in- dustry standard parameter of lbm of fuel being burned divided by lbf

44、 of thrust the engine produces at that min- imum point.0037 Low 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 1.45.0038 Low c

45、orrected fan tip speed is the actual fan tip speed in feet per second divided by an industry stand- ard temperature correction of (Tambient deg R) / 518.7)0.5. The Low corrected fan tip speed as disclosed herein according to one non-limiting embodiment is less than about 1150 feet per second (351 me

46、ters per sec- ond).0039 The fan 42 includes a plurality of hybrid metallic fan blades 62. As shown in Figure 2, each fan blade 62 includes a blade body 64 having an inner surface 70 in- cluding a plurality of cavities 66, such as grooves or open- ings, surrounded by ribs 68. A plurality of strips or

47、 pieces of a low density filler 72 are each sized to fit in one of the plurality of cavities 66. The fan blade 62 also includes a cover 74 and a leading edge sheath 76 attached to the blade body 64.0040In one example, the blade body 64 is made of aluminum or an aluminum alloy. Employing aluminum or

48、an aluminum alloy for the blade body 64 and the cover 74 provides a cost and weight savings. There is one strip or piece of the low density filler 72 for each of the plurality of cavities 66 of the blade body 64. In one example, the low density filler 72 is a foam. In one example, the foam is alumin

49、um foam. The low density filler 72 is secured in the cavities 66 with an adhesive 78, shown schematically as arrows. In one example, the adhesive 78 is urethane. In another example, the adhesive 78 is an epoxy film. 0041The cover 74 is then secured to the blade body 64 with an adhesive 80, shown sch

50、ematically as arrows. In one example, the adhesive 80 is urethane. In one ex- ample, the cover 74 is made of aluminum or an aluminum alloy. The adhesive 80 then cured during a bonding cure cycle in a pressure vessel.0042The leading edge sheath 76 is then attached tothe blade body 64 with an adhesive

51、 layer 82. In one ex- ample, the adhesive layer 82 includes an adhesive film supported by a scrim cloth. In one example, the adhesive film is an epoxy film. In one example, the scrim cloth is nylon. In one example, the scrim cloth is mesh in struc- ture. In one example, the leading edge sheath 76 is

52、 made of titanium or a titanium alloy. The adhesive film in the adhesive layer 82 is then cured during a sheath bonding cure cycle in an autoclave.0043 To attach the cover 74 to the blade body 64, theadhesive 80 is applied near a first edge 84 of an inner surface 86 of the cover 74. The adhesive 80

53、is contained in a body 88 and is dispensed through a nozzle 90. The adhesive 80 can be applied manually or robotically, shown schematically as a box 92.0044 As shown in Figure 4, once the adhesive 80 is applied, a toothed instrument 94 is positioned on the inner surface 86 of the cover 74 and moved

54、along the length L of the cover 74 from the first edge 84 to an opposing second edge 96. After the toothed instrument 94 is along the length L of the inner surface 86 of the cover 74, a plurality of rows 98 of adhesive 80 are defined.0045 As shown in Figure 5, in one example, the toothed instrument

55、94 is a toothed trowel that includes a plurality of teeth 100 that are separated by a space 102. In one example, the height of the space 102 between each tooth 100 is 1/8 of an inch (0.3175 cm). In one ex- ample, the teeth 100 are spaced apart by a distance of 1/8 (0.1375 cm). The depth, shape and s

56、pacing of the teeth 100 determine a final cured bondline thickness of the adhesive 80 by controlling an amount of the adhesive 80 on the inner surface 86 of the cover 74. In one exam- ple, the toothed instrument 94 is made of plastic. In one example, the tooth instrument 94 is a roller including a p

57、lurality of teeth. As the roller is moved over the inner surface 86 of the cover 74, the plurality of teeth create the plurality of rows 98 of adhesive 80.0046 The toothed instrument 94 controls the amount and distribution of the adhesive 80 spread over the inner surface 86 of the cover 74 to provid

58、e consistency and to remove any excess adhesive 80. This also allows for consistency for different fan blades 62, reducing weight variations in different fan blades 62. The toothed instru- ment 94 makes application of the adhesive 80 on the inner surface 86 of the cover 74 less sensitive to variation as it removes excess adhesive 80 and leaves a consist- ent amount of adhesive 80 on the cover 74. This also allows for the adhesive 80 to be applied manually