United States Patent [19J
`Martin
`
`111111111111111111111111111111111111111111111111111111111111111111111111111
`US005174715A
`5,174,715
`[ II) Patent Number:
`[45) Date of Patent: Dec. 29, 1992
`
`[54)
`[75]
`(73]
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`[21)
`
`[22]
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`[62]
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`(51]
`(52)
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`[58]
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`[56]
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`TURBINE NOZZLE
`
`Inventor:
`
`Jack R. Martin, Bedford, Mass.
`
`Assignee: General Electric Company,
`Cincinnati, Ohio
`Appl. No.: 785,677
`Filed:
`
`. Oct. 31, 1991
`
`Related U.S. Application Data
`Division ofSer. No. 627,161, Dec. 13, 1990.
`Int. ct.s ................................................ FOlD 1/ 02
`U.S. Ct. .............................. 415/ 209.4; 415/210.1;
`29/464; 29/889.21; 29/889.22
`Field of Search ........... 29/889.21, 889.22, 889.23,
`29/406,464, 527.3; 415/191,208.5, 183, 185,
`181, 209.3, 209.4, 210.1; 416/241 ; 269/909, 40,
`289 MR, 296
`
`References Cited
`U.S. PATENT DOCUMENTS
`1,932,264 10/1933 Dickinson ........................ 415/209.4
`2.475.772 7/1949 Allen et al. ....................... 269/40 X
`2,821.778 2/1958 Wilken .................................. 269/40
`3,519.366 7/1970 Campbell ..................... 415/209.3 X
`3,836,282 . 9/1974 Mandelbaum et a!. .......... 415/209.4
`3.849,023 11/1974 Klompas ...................... 415/209.4 X
`4,128.929 12/1978 DeMusis ................ , ....... 29/156.8 B
`4,501,095 2/1985 Drinkuth et at. ............ 29/889.21 X
`4.589,175 5/1986 Arrigoni ......................... 29/156.8 B
`4,601,1 10 7/1986 Donaldson ............................ 33/547
`
`4.726,101 2/ 1988 Draghi et al. .................. 29/156.8 B
`4,735,451 4/ 1988 Wojciechowski et al. ...... 294/103. 1
`4.798,520 1/1989 Partington et al. .......... 29/889.21 X
`4,829,720 5/1989 Cavalieri ........................... 51/217 R
`4,884,951 12/1989 Meylan et al. ...................... 416/191
`4,896,408 1/1990 Fraser ............................. 29/156.8 B
`5,001 ,830 3/1991 Partington et al. .............. 29/889.21
`5,022,818 6/1991 Sealzo .............................. 415/209.3
`Primary Examiner-Edward K. Look
`Assistant Examiner-T odd Mattingly
`Allorney, Agent. or Firm-Jerome C. Squillaro; Nathan
`D . Herkamp
`[57)
`ABSTRACT
`A method of manufacturing a turbine nozzle for obtain·
`ing a predetermined value of throat area between adja(cid:173)
`cent ones of nozzle vanes is disclosed. The method
`includes providing a first vane, providing a datum for
`locating the first vane relative to an adjacent vane in the
`turbine nozzle, and fixturing the first vane relative to
`the datum for providing a trailing edge nest having six
`supports for predeterminedly locating the first vane
`relative to the adjacent vane. T he trailing edge nest
`includes four trailing edge supports for locating the
`vane trailing edge to define a hinge axis extending along
`the trailing edge about which the vane is rotatable. A
`radial support radially locates the vane, and a throat
`support predeterminedly locates the vane about the
`hinge axis for obtaining the predetermined value of the
`th roat area.
`
`10 Claims, 7 Drawing Sheets
`
`PAGE 1 OF 15
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`PETITIONERS' EXHIBIT.1120
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 1 of 7
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`5,174,715
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`FIG. 1
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`20
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`FIG. 2
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`PAGE 2 OF 15
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 2 of 7
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`5,174,715
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`PAGE3 OF 15
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 3 of 7
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`5,174,715
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`PAGE 4 OF 15
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`U.S. Patent
`US. Patent
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`Dec. 29, 1992
`Dec. 29, 1992
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`PAGE 5 OF 15
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`PAGE 5 OF 15
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 5 of 7
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`PAGE 6 OF 15
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 6 of 7
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`5,174,715
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`PAGE 7 OF 15
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`U.S. Patent
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`Dec. 29, 1992
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`Sheet 7 of 7
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`5,174,715
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`PAGES OF 15
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`

`

`1
`
`TURBINE NOZZLE
`
`5,174,715
`
`The U.S. Government has rights in this invention
`pursuant to Contract No. F33657-82-C-2188 awarded
`by the Department of the Air Force.
`This is a division of application Ser. No. 627,161, filed
`Dec. 13, 1990.
`
`TECHNICAL FIELD
`The present invention relates generally to gas turbine
`engines, and, more specifically, to a method of manufac(cid:173)
`turing a gas turbine engine turbine nozzle for obtaining
`a predetermined value of throat area between adjacent
`ones of turbine vanes thereof.
`
`BACKGROUND ART
`A conventional gas turbine engine includes in serial
`flow communication a compressor, a combustor, and a
`turbine. The compressor provides compressed airflow
`to the combustor wherein it is mixed with fuel and
`ignited for generating combustion gases which then
`flow to the turbine which extracts energy therefrom for
`powering the compressor.
`The turbine includes one or more stages with each
`stage having an annular turbine nozzle for channeling
`the combustion gases to a plurality of rotor blades. The
`turbine nozzle includes a plurality of circumferentially
`spaced stator vanes fixedly joined at their roots and tips
`to annular, radially inner and outer bands.
`Each of the nozzle vanes has an airfoil cross section
`with a leading edge, a trailing edge. and pressure and
`suction sides extending therebetween. In one type of
`turbine nozzle, the trailing edge of one vane is spaced
`from the suction side of an adjacent vane between its
`leading and trailing edges to define a throat having a
`minimum flow area for the combustion gases channeled
`between adjacent vanes. Adjacent ones of the vanes
`define individual throat areas and collectively they
`define a total throat area. These areas are specified by
`each particular engine design and are critical factors
`affecting performance and stall margin of the gas tur(cid:173)
`bine engine.
`Furthermore, the total throat area is preferably ob(cid:173)
`tained by providing substantially uniform individual
`throat areas between the adjacent vanes. Variations in
`throat area between adjacent vanes can provide unde(cid:173)
`sirable aero-mechanical excitation pressure forces
`which may lead to undesirable vibration of the rotor
`blades disposed downstream from the nozzle.
`There exist numerous methods for manufacturing gas
`turbine engine turbine nozzles which provide varying
`degrees of accuracy of the individual and total throat
`areas. For example, one method utilizes individual
`vanes having integral inner and outer band segments
`which are joined together for forming arcuate nozzle
`segments. A second method utilizes arcuate inner and
`outer band segments each having a plurality of circum(cid:173)
`ferentially spaced apertures for receiving ·the roots and
`tips of the nozzle vanes which are then joined thereto
`by tack welding and brazing. A third method utilizes
`individual vanes which are fixed relative to each other
`and then inner and outer band segments are cast over
`the roots and tips thereof for forming arcuate nozzle
`segments. The separate arcuate nozzle segments in these
`three exemplary methods include two or more vanes,
`with the segments being conventionally joined together
`for forming a complete 360• annular turbine nozzle.
`
`10
`
`2
`In all of these methods of manufacturing the turbine
`nozzle, each of the individual vanes and inner and outer
`band segments is separately manufactured and, there(cid:173)
`fore, subject to inherent manufacturing tolerances. The
`5 tolerances are additive and, therefore, stack-up during
`assembly of the turbine nozzle which adversely affects
`the ability to achieve relatively small variation in the
`individual throat areas and in the desired total throat
`area.
`In one typical gas turbine engine design, it is desirable
`to maintain the individual and total throat areas to
`within about±!%. However, using conventional man(cid:173)
`ufacturing methods, it is not believed that this small
`tolerance is achievable. In order to appreciate the small-
`IS ness of this tolerance and the difficulty in obtaining it,
`examination of a particular method of manufacturing a
`turbine nozzle will be helpful.
`More specifically, one conventional method of manu(cid:173)
`facturing a turbine nozzle includes a conventionally
`20 known leading edge nest for fixturing individual vanes
`in space during manufacture for obtaining the required
`throat area. It is known that to fully locate in space a
`three-dimensional object, such as a nozzle vane, re(cid:173)
`quires six point supports for preventing translation
`25 along the three axes of a three axis orthogonal coordi(cid:173)
`nate system (e.g. X, Y, and Z axes) and for preventing
`rotation about each of the three axes. Accordingly,
`conventional fixturing devices are used for predeter(cid:173)
`minedly locating individual nozzle vanes in space rela-
`30 tive to a reference datum so that when adjacent vanes
`are assembled together they are predeterminedly lo(cid:173)
`cated relative to each other for providing among other
`things the required throat area therebetween.
`In the leading edge nest, a nozzle vane is fixtured, or
`35 supported at six points relative to the datum during the
`manufacturing process. The leading edge nest includes
`a first pair of radially spaced leading edge supports for
`opposing yaw of the vane relative to, for example, the
`chord of the vane. A second pair of radially spaced
`40 midchord supports contact the suction side of the vane
`between the leading and trailing edges thereof for op(cid:173)
`posing roll of the vane relative to the chord. A radial
`support radially locates the vane. And, an aft support
`contacts the suction side of the vane adjacent to the
`45 trailing edge for opposing pitch of the vane relative to
`the radial axis thereof. The six supports also oppose
`translation of the vane in all three axes. The vane is
`typically held against or restrained against the six sup(cid:173)
`ports by conventional means including spring clamps,
`50 such as those used to position hardware during welding,
`and set screws as appropriate to react machining forces.
`The leading edge nest provided by the fixturing device,
`therefore, predeterminedly positions the vane in space
`relative to the datum and, relative to adjacent ones of
`55 the vanes.
`Once the vane is fixtured, then the integral bands of
`the first method may be conventionally machined rela(cid:173)
`tive thereto, or the bands including the apertures of the
`second method may be spot welded and then brazed
`60 thereto, or in the third method, the bands may be cast to
`the vanes.
`After a turbine nozzle has been conventionally manu(cid:173)
`factured, the individual throat areas between adjacent
`ones of the vanes are measured for determining the
`65 uniformity thereof. If the individual throat areas do not
`meet applicable specifications, they may be convention(cid:173)
`ally benched, wherein the trailing edges thereof are
`permanently abrasively ground away in order to adjust
`
`PAGE 9 OF 15
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`

`

`5,174,715
`
`4
`DISCLOSURE OF INVENTION
`A method of manufacturing a turbine nozzle for ob(cid:173)
`taining a predetermined value of throat area between
`adjacent ones of nozzle vanes is disclosed. The method
`includes providing a first vane, providing a datum for
`locating the first vane relative to an adjacent vane in the
`turbine nozzle, and fixturing the first vane relative to
`the datum for providing a trailing edge nest having six
`supports for predeterminedly locating the first vane
`relative to the adjacent vane. The trailing edge nest
`includes four trailing edge supports for locating the
`vane trailing edge to define a hinge axis extending along
`the trailing edge about which the vane is rotatable. A
`radial support radially locates the vane, and a throat
`support predeterminedly locates the vane about the
`hinge axis for obtaining the predetermined value of the
`throat area. The turbine nozzle manufactured using this
`method has reduced throat stack-up tolerances.
`
`3
`the individual throat areas. In this way, excessive stack-
`up tolerances which result in unacceptable variation in
`throat areas between adjacent vanes may be accommo(cid:173)
`dated after the initial manufacturing of the turbine noz(cid:173)
`zle. However, benching is only effective for correcting 5
`a certain small amount of deviation in throat area, and is
`generally ineffective for correcting the total throat area
`of all the nozzle vanes. Furthermore, in nozzle vanes
`conventionally coated for improved nozzle life, bench(cid:173)
`ing is not possible since the coatings are typically thin 10
`and their effectiveness would be unacceptably dam(cid:173)
`aged.
`The leading edge nest ensures. that the leading edges
`of adjacent vanes are aligned in a common plane and
`that the vanes extend in an aft direction therefrom for 15
`providing the predetermined converging nozzle be(cid:173)
`tween adjacent ones of the vanes ending in the desired
`throat, and throat area thereof. However, the accuracy
`of the throat area is a function of the accuracy of the
`tolerances of the vanes and the assembly thereof. For 20
`example, the thickness of an individual vane has a first
`tolerance, and, if the vanes are conventionally coated
`on both sides, each of the coatings has a second toler(cid:173)
`ance. Accordingly, the accuracy of the throat area is
`directly related to the stack-up of these two tolerances
`since the leading edge nest uses the aft support on the
`suction side of the blade and the throat is defined on the
`pressure side of the blade between the trailing edge and
`an adjacent vane. In this example, the initial vane cast- 30
`ing may have a first tolerance of 5 mils (0.13 mm) on
`each side thereof, and a conventional coating on each
`side of the blade may have a second tolerance of 5 mils
`(0.13 mm) resulting in a total tolerance stack-up of
`about 20 mils (0.51 mm) for both sides. An exemplary 35
`throat area required between adjacent vanes may be
`defined in part by the distance between the blades of
`about 0.555 inches (14.1 mm). A!% tolerance on the
`throat area would then be about 2.75 mils (0.07 mm).
`Dividing the 20 mils (0.51 mm) tolerance stack-up by 40
`the desired tolerance of 2.75 mils (0.07 111m) results in
`about a 700% potential error. If the nozzle is fabricated
`by the second or third method described above, addi(cid:173)
`tional stack-up and error will be added to the above
`error.
`
`25
`
`45
`
`BRIEF DESCRIPTION OF DRAWINGS
`The novel features believed characteristic of the in-
`vention are set forth and differentiated in the claims.
`The invention, in accordance with preferred and exem(cid:173)
`plary embodiments, together with further objects and
`advantages thereof is more particularly described in the
`following detailed description taken in conjunction
`with the ·accompanying drawing in which:
`FIG. 1 is a perspective view of an arcuate section of
`an annular gas turbine engine· turbine nozzle.
`FIG. 2 is a circumferential sectional view of the tur(cid:173)
`bine nozzle illustrated in FIG. 1 taken along line 2-2.
`FIG. 3 is a perspective upstream facing view of a
`portion of the turbine nozzle illustrated in FIG. 1 taken
`along line 3-3.
`FIG. 4 is a schematic representation of a nozzle vane
`fixtured using a leading edge nest for undergoing preci(cid:173)
`sion grinding.
`FIG. 5 is a radial sectional view of an exemplary
`nozzle vane restrained in ·a fixturing device.
`FIG. 6 is a schematic representation of fixturing a
`nozzle vane using a trailing edge nest.
`FIG. 7 is a radial top view of the nozzle vanes illus(cid:173)
`trated in FIG. 6 showing the trailing edge nest.
`FIG. 8 is a perspective schematic representation of a
`fix turing device for fix turing a nozzle vane using a trail(cid:173)
`ing edge nest as illustrated in FIGS. 6 and 7.
`FIG. 9 is a top view of the nozzle vane and fixturing
`device illustrated in FIG. 8 taken along line 9-9.
`FIG. 10 is a transverse sectional view of the nozzle
`vane and fixturing device illustrated in FIG. 9 taken
`along line 10-10.
`FIG. 11 is a perspective view of a nozzle vane includ(cid:173)
`ing integral outer and inner band segments fixtured
`55 using the trailing edge nest illustrated in FIGS. 6 and 7.
`FIG. 12 is a perspective of two of the nozzle vanes
`illustrated in FIG. 11 joined to each other at the outer
`and inner band segments.
`FIG. 13 is a perspective view of an alternate embodi-
`60 ment of the present invention including adjacent nozzle
`vanes each fixtured using the trailing edge nest illus(cid:173)
`trated in FIGS. 6 and 7 and joined to inner and outer
`band segments.
`FIG. 14 is another embodiment of the present inven-
`65 tion illustrating adjacent nozzle vanes fixtured relative
`to each other using the trailing edge nest illustrated in
`FIGS. 6 and 7 and joined to each other by casting of
`inner and outer band segments.
`
`50
`
`OBJECTS OF THE INVENTION
`Accordingly, it is one object of the present invention
`to provide a new and improved method of manufactur(cid:173)
`ing a gas turbine engine turbine nozzle.
`Another object of the present invention is to provide
`a method of manufacturing a turbine nozzle for reduc(cid:173)
`ing stack-up tolerances.
`Another object of the present invention is to provide
`a method of manufacturing a turbine nozzle for reduc(cid:173)
`ing stack-up tolerances at a nozzle throat defined be(cid:173)
`tween adjacent ones of nozzle vanes.
`Another object of the present invention is to provide
`a method of manufacturing a turbine nozzle for obtain(cid:173)
`ing a predetermined value of throat area between adja(cid:173)
`cent ones of the nozzle vanes.
`Another object of the present invention is to provide
`a method of manufacturing a turbine nozzle which pro(cid:173)
`vides improved uniformity in throat areas between adja(cid:173)
`cent ones of nozzle vanes.
`Another object of the present invention is to provide
`new and improved turbine nozzles manufactured by the
`improved manufacturing method.
`
`PAGE 10 OF 15
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`

`

`5
`MODE(S) FOR CARRYING OUT THE
`INVENTION
`Illustrated in FIG. 1 is a portion of an annular, 360'
`turbine nozzle or diaphragm 10 disposed coaxially 5
`about a longitudinal, or axial, centerline 12 of a gas
`turbine engine. The nozzle 10 includes a plurality of
`circumferentially spaced nozzle vanes 14 fixedly joined
`to radially inner and outer annular bands 16 and 18,
`respectively. The inner band 16 has an inner radius R 10
`relative to the centerline axis 12 for conventionally
`positioning the vanes 14 in line with combustion gases
`20 channeled thereto from a conventional gas turbine
`engine combustor (not shown). The turbine nozzle 10
`may be any turbine nozzle including the conventionally 15
`known high pressure turbine nozzle disposed at the
`outlet of the combustor, or it may be a turbine nozzle
`disposed at a downstream stage of the turbine.
`Each vane 14 includes a root 22 conventionally
`fixedly joined to the inner band 16, a tip 24 convention- 20
`ally fixedly joined to the outer band 18, a leading edge
`26 facing in an upstream direction, a trailing edge 28
`facing in a downstream direction, and oppositely facing
`suction, or convex, and pressure, or concave, sides 30
`and 32, respectively, extending from the leading edge 26 25
`to the trailing edge 28 and between the root 22 and the
`tip 24.
`As illustrated in FIGS. 2 and 3, each of the vanes 14
`includes a throat line 34 extending from the root 22 to
`the tip 24 on the vane suction side 30 for defining with 30
`the trailing edge 28 of an adjacent one of the vanes 14 a
`throat 36 of minimum throat area A. All of the leading
`edges 26 of the vanes 14 are preferably located in a
`common leading edge plane 38, and similarly, all of the
`vane trailing edges 28 are also located in a common 35
`trailing edge plane 40. Adjacent ones of the vanes 14
`define therebetween a converging channel 42 for chan(cid:173)
`neling the combustion gases 20 between the vane 14 and
`through the throats 36 and downstream therefrom to a
`conventional turbine rotor stage (not shown).
`As illustrated in FIG. 3, each of the vanes 14 extends
`generally parallel to a radial axis 44 extending out(cid:173)
`wardly from the centerline axis 12. However, the trail(cid:173)
`ing edge 40 may be inclined at an angle M relative to the
`radial axis 44. Each of the throats 36 extends from the 45
`vane root 22 to the vane tip 24 and the throat area A is
`defined as that planar area between the root 22, tip 24,
`pressure side 32 at the trailing edge 28, and the throat
`line 34 on the suction side 30 of an adjacent vane 14.
`The throat area A is therefore directly related to the 50
`heights of the vane 14 at the trailing edge 28 and the
`throat line 34, and the circumferential spacing S be(cid:173)
`tween the pressure side 32 at the trailing edge 28 and the
`suction side 30 of an adjacent vane at the throat line 34.
`An exemplary spacing S between the vanes 14 occurs at 55
`the vane pitch line P disposed radially equidistantly
`between the vane root 22 and tip 24.
`In accordance with the present invention, an im(cid:173)
`proved method of manufacturing the turbine nozzle 10
`for obtaining a predetermined value of the throat area A 60
`is provided. The method is effective for reducing stack-
`up tolerances during the manufacture of the nozzle 10
`from the plurality of vanes 14 and, therefore, for im(cid:173)
`proving the uniformity of the individual throat areas A
`of the throats 36, as well as providing an improved total 65
`throat area of the individual throat areas A collectively.
`The method preferably includes the step of providing
`a first one of the vanes 14, designated 14a as illustrated
`
`40
`
`5,174,715
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`6
`in FIG. 4, which has a chord C having a predetermined
`chord length L between the leading edge 26 and the
`trailing edge 28. Although in the preferred embodi(cid:173)
`ment, the chord C is that chord at the pitch line P, the
`chord at other radial sections of the blade 14 may also
`be used. All of the vanes 14, including the first vane 14a,
`may be conventionally manufactured to required speci(cid:173)
`fications for particular engines for providing the re(cid:173)
`quired finally dimensioned, or final blade contour in(cid:173)
`cluding the suction and pressure sides 30 and 32 and the
`predetermined chord lengths, e.g. L, for ensuring an
`accurate channel 42 between adjacent vanes 14 after
`manufacture or assembly in accordance with the pres(cid:173)
`ent invention.
`In one embodiment of the present invention, the first
`vane 14a may be provided by providing an initial vane
`14i as illustrated in FIG. 4 which is identical to the first
`vane 14a except for including a trailing edge extension
`46 (shown in dashed line) which is about 30 mils (0.76
`mm) longer than the required length of the first vane
`14a. The method also includes fixturing the initial vane
`14i as illustrated schematically in FIG. 4 relative to a
`datum 48 for providing a first, or leading edge nest
`having six point supports for predeterminedly locating
`the initial vane 14i in space relative to the datum 48 and
`an adjacent vane 14b (trailing edge portion shown in
`dashed line). The leading edge nest is conventional and
`provides the six point supports for locating the initial
`vane 14i in space. The initial vane 14i is conventionally
`restrained against the six supports by conventional
`means including welding spring clamps and/or adjust(cid:173)
`able set screws in accordance with conventional prac(cid:173)
`tice.
`As illustrated in FIG. 4, the datum 48 is a conven(cid:173)
`tional three axis (X, Y, and Z axes) coordinate system
`used for locating the initial vane 14i in space so that it
`may be machined by conventional machines such as a
`precision grinder represented schematically by the
`grinding wheel SO. The grinding wheel SO convention(cid:173)
`ally rotates about its longitudinal axis SOa and is conven(cid:173)
`tionally translatable along the·trailing edge extension 46
`for the precise removal thereof.
`The leading edge nest conventionally includes a first
`pafr of radially spaced leading edge supports shown
`schematically as arrows A 1 and A, which contact the
`leading edge 26 of the initial vane 14i for opposing or
`preventing yaw of the initial vane 14i. One of the lead(cid:173)
`ing edge supports, Ar, is preferably spaced adjacent to
`the tip 24 of the .vane 14i and the other of the leading
`edge supports, A,, is preferably positioned adjacent to
`the root 22 of the vane 14i. The two leading edge sup(cid:173)
`ports Ar and A, prevent yaw of the initial vane 14i
`which is defined as rotation of the vane 14i about an axis
`perpendicular to the chord C and shown schematically
`as yaw angle yin FIG. 4.
`A second pair of radially spaced midchord supports
`Br and B, contact the suction side 30 of the initial vane
`14i between the leading and trailing edges thereof for
`opposing or preventing roll of the initial vane 14i. Roll
`is defined as rotation of the vane 14i generally about the
`chord C and is represented schematically by the roll
`angle r in FIG. 5.
`An aft support represented schematically by the
`arrow Cp contacts the initial vane 14i suction side 30
`adjacent to the trailing edge 28, and preferably at the
`pitch line P for opposing or preventing pitch of the
`initial vane 14i. Pitch is rotation of the vane 14i gener(cid:173)
`ally about its radial axis 44 (i.e. axis perpendicular to
`
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`5,174,715
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`8
`7
`As illustrated in FIGS. 6 and 7, each of the vanes 14
`both the yaw and roll axes) and is shown schematically
`which form the turbine nozzle 10 is provided in turn as
`asp is FIG. 4.
`the first vane 14a for being suitably fixtured in accor(cid:173)
`Of course, the leading edge supports, the midchord
`supports, and the aft support also effectively oppose
`dance with another feature of the present invention.
`5 The reference datum 48 is again provided for locating
`translation of the initial vane 14i, and along with a radial
`the first vane 14a relative to the adjacent vane 14b
`support designated by the arrow D, completely locate
`(shown in dashed line). In contrast to the conventional
`the vane 14i in space. The radial support D radially
`fixturing step illustrated in FIG~. 4 and 5 wherein the
`locates the initial vane 14i by supporting it, for example,
`at the root 22.
`initial vane 14i was fixtured for providing the leading
`10 edge nest (A,, A1, B,, Bt, Cp, and D) the method in(cid:173)
`With the initial vane 14i conventionally fixtured in
`space relative to the datum 48, the trailing edge exten(cid:173)
`cludes fixturing the first vane 14a relative to the datum
`sion 46 may be precisely removed by the grinding
`48 for providing a trailing edge nest having six point
`wheel. SO in accordance with conventional practice for
`supports for predeterminedly locating in space the first
`providing the first vane 14a having the predetermined
`vane 14a relative to the adjacent vane 14b.
`chord lengths between the leading edge 26 and the 15
`The trailing edge nest includes four trailing edge
`trailing edge 28. In the preferred embodiment of the
`supports E 1, E,, Ft. and F,, which define a hinge axis 54
`extending along the trailing edge 28 about which hinge
`invention, the grinding wheel SO removes the trailing
`axis 54 the first vane 14a is rotatable like a door. Of
`edge extension 46 for providing a substantially square-
`course, various orientations and configurations of the
`ended trailing edge 28 as shown, for example, in FIGS.
`20 trailing edge 28 may be used depending upon particular
`4 and 5.
`nozzle designs. The trailing edge 28 may be disposed
`The datum 48 may conventionally be one or more
`radially to the centerline axis 12, or at the small angle M
`datums for ensuring that the initial vane 14i is suitably
`relative thereto as shown in FIG. 3, and may be straight
`fixtured, and the trailing edge extension 46 is suitably
`removed for providing the first vane 14a having the
`or bowed. In all cases, however, the hinge axis 54 may
`required final chord length dimensions before assembly 25 still be defined for allowing the vane 14a to pivot like a
`door.
`into the turbine nozzle 10. Each of the vanes 14 may be
`similarly manufactured so that all of the vanes 14 are
`The trailing edge nest also includes a radial support,
`ready for final assembly into the turbine nozzle 10. In
`which may be the same as the radial support D dis-
`any embodiment of the invention wherein the vanes 14
`closed above, for radially locating the first vane 14a
`are to be coated with conventional coatings, they are 30 relative to the datum 48, and a throat support Gp for
`then applied at this time for providing the finally dimen-
`predeterminedly locating the first vane 14a about the
`sioned vanes 14. Of course, any additional thickness of
`hinge axis 54 for obtaining the predetermined value of
`the vane 14 due to the coatings thereof, is suitably ac-
`the throat area A. Just as with the leading edge nest
`counted for in the initial dimensions of the vane 14.
`described above, the trailing edge nest supports E 1, E,,
`The leading edge nest may be provided by a conven- 35 F~o F,, D, and Gp are also shown as arrows indicating
`tiona! fixture 52, a portion of which is illustrated in FIG.
`the supports and where they preferably contact the first
`S. The fixture 52 provides all six support points A,, A~o
`vane 14a for supporting the first vane 14a. The first
`B,, B~o Cp, and D. Two of several restraints designated
`vane 14a is also conventionally restrained against the six
`schematically by arrows F1 and F2 are shown for re-
`supports by conventional spring clamps, and/or set
`straining the initial vane 14i against the six supports to 40 screws which are shown schematically in FIG. 6 by the
`arrows labeled F3, F4, Fs and F6 near the leading and
`ensure that the initial vane 14i is rigidly captured for
`trailing edges 26 and 28 of the first vane 14a.
`undergoing the grinding operation. The length of chord
`C may be measured during the grinding operation by
`The trailing edge supports preferably include a first
`pair of radially spaced trailing edge supports E 1 and E,
`any conventional means to ensure that the predeter-
`mined values thereof are obtained from the root 22 to 45 for opposing yaw of the first vane 14a, and a second pair
`the tip 24 of the initial vane 14i. However, as illustrated
`of radially spaced supports F~o and F, for opposing roll
`in FIG. 5, the length of chord C may be accurately
`of the first vane 14a. The throat support Gp opposes
`determined by measuring an alternate chord length Lm
`pitch of the first vane 14a about the hinge axis 54. As
`described above, yaw is the rotation of the first vane 14a
`defined between the vane pressure side 32 at the trailing
`edge 28 and a line contacting the initial vane 14i adja- 50 about an axis generally perpendicularly to the chord C
`cent to the leading edge 26 which line is disposed per-
`and designated as yaw angle yin FIG. 6, roll is rotation
`pendicularly to the line of length Lm which also
`of the first vane 14a about the chord C at the pitch line
`P and designated as roll angle r, and pitch is rotation of
`contacts the initial vane 14i adjacent to the leading edge
`26. Measurement of the length Lm is preferred since it is
`the first vane 14a about the hinge axis 54 and designated
`readily obtainable by placing straight edges against the 55 as pitch angle p. With the first vane 14a suitably re-
`strained against the six supports, yaw, roll, pitch, and
`surfaces of the initial vane 14i. Of course, other conven-
`tiona! techniques for accurately measuring the length of
`translation along the three axes are all prevented and
`the first vane 14a is, therefore, suitably positioned in
`chord C may be utilized.
`space relative to the datum 48.
`Providing the first vane 14a with accurate, i.e. to
`design specifications, chord lengths ensures proper 60 A significant feature of the present invention is the
`alignment between the respective leading edges 26 and
`trailing edge nest which allows the first vane 14a to be
`respective trailing edges 28 as described further herein-
`rotated during assembly about the hinge axis 54 as ill us-
`below. Providing the square-ended trailing edges 28
`trated in FIG. 7. During fixturing of the first vane 14a,
`improves the accuracy of obtaining accurate, i.e. to
`the vane trailing edge 28