US3059902A - Adjustable nozzle and intermediate inner shroud support - Google Patents

Description

oct. 23, 1962 ADJUSTABLE NOZZLE AND INTERMEDIATE INNER SHROUD SUPPORT Filed July 3, 1961 G. F. SAVONUZZI 2 Sheets-Sheet l G. F. SAVONUZZI y Oct. 23, 1.962

ADJUSTABLE NOZZLE AND INTERMEDIATE INNER SHROUD SUPPORT 2 Sheets-Sheet 2 Filed July 5, 1961 INVENTOR. 6fm/477277 fdvayfzzzzz'.

3,059,902 ADJUSTABLE NZZLE AND INTERMEDIATE INNER SILRUD SUPPRT Giovanni F. Savonuzzi, Birmingham, Mich., assigner to Chrysler Corporation, Highland Parli, Mich., a corporation of Delaware Filed duly 3, 196i, Ser. No. 1231,396

6 tClaims. (Cl. 253-73) This invention relates to gas turbine engines particularly adapted for automotive use and has for an important object the provision of improved means for supporting adjustable nozzles and an intermediate inner shroud, the latter extending `axially between a compressor driving rotor and a power rotor to denne the inner wall of an annular passage for motive gases driving7 said rotors, and the adjustable nozzles being arranged in said passage upstream of the power rotor to adjust the angle of attack thereagainst of said motive gases.

In one type of gas turbine engine of the character described, the adjustable nozzles are carried respectively by a plurality of spindles journalled in and extending at circumferentially spaced locations generally radially through an outer shroud which extends coaxially `around the intermediate inner shroud to define the outer wall of the gas passage. inasmuch as the intermediate inner shroud extends between the two rotors, diculty has been experienced heretofore in suitably supporting that shroud without undue expense and the introduction of undesirable impedance to the flow of motive gases. Attempts have been made to support the intermediate inner shroud by the radially inner ends of the adjustable nozzles, but such a support has not been entirely successful Ibecause the combined axial pressure force of the motive gases on the intermediate inner shroud and nozzles tends to bend the spindles unless considerable expense and weight are added by making the spindles and their journal mountings sufficiently strong to resist the aforesaid axial pressure forces.

Another object of the invention is to provide improved means for supporting an intermediate inner shroud and for rotatably supporting a plurality of adjustable nozzles, whereby the axial pressure forces of the motive gases on the intermediate shroud are shielded from the nozzle journal mountings, wherein adequate means yare readily provided to accommodate relative thermal expansion and contraction of the intermediate and outer shrouds, and wherein assembly and disassembly of the structure are readily accomplished.

Another and more specific object is to provide a gas turbine engine construction having a compressor driving rotor and a power rotor arranged coaxially and an annular gas passage defined by inner and outer shrouds `for directing motive gases to the peripheral blades of the rotors. A plurality of fiow directing nozzles are arranged circumferentially within the passage immediately upstream of the power rotor, each nozzle comprising a fixed part and a pivotal part, and the pivotal part being secured to a spindle for pivoting therewith. Each spindle extends generally radially through and is journalled in the outer shroud. The inner shroud includes an intermediate inner shroud secured lto the fixed part of each nozzle to be supported thereby. Each fixed nozzle part is secured to one-half of a split bushing seated snugly within a recess in the outer shroud and extending around one side of the lower end of the spindle for the associated pivotal nozzle part. The other half of the split bushing extends around the other side of the spindle in opposition to the first bushing half and is also seated snugly within the aforesaid recess in the outer shroud. By this construction, axially directed forces of the motive gases against the intermediate inner shroud are carried by the xed nozzle part to the first-named bushing half and thence through 3,059,902 Patented Oct. 23, 1962 Ithe second bushing half to the outer shroud, whereby the spindles extending through the split bushings are shielded from these axial forces.

Another object is to provide such a structure wherein each split bushing is shiftable axially of its associated spindle to accommodate theremally induced dimensional changes in the intermediate inner shroud, and wherein the latter `shroud comprises two sections, one section being attached to the fixed nozzle parts and being insertable therewith and with the split bushing parts into assembled position through an end of the outer shroud, the adjustable nozzle parts and attached spindles being adapted to be assembled thereafter with the outer shroud through said end thereof, and the second section of the inner intermediate shroud being adapted to be assembled thereafter `to the first-named section through said end.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

FIGURE l is a longitudinal mid sectional view through a fragmentary portion of a gas turbine engine at the region of the rotors.

FIGURE 2 is a fragmentary enlargement of the portion of FIGURE l enclosed within the circle 2, illustrating the support for the nozzle and intermediate inner shroud.

FIGURE 3 is a sectional view taken in the direction of the arrows 3-3 of FIGURE 2.

FIGURE 4 is a sectional view through the nozzle, taken in the direction of the arrows 4 4 of FIGURE 2.

FIGURE 5 is a fragmentary isometric view showing the fixed nozzle attached to the intermediate inner shroud and half of the split bushing.

FIGURE 6 is a view taken in the direction of the arrows substantially along the line 6-6 of FIGURE 5, showing the curvature of the split bushing half attached to the fixed nozzle.

It is to be understood that the invention is not limited in its application `to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to the drawings, ya fragmentary portion of a gas turbine engine illustrated generally by the numeral 9 comprises a compressor rotor 10 and a coaxial rotor 11 arranged in tandem with their peripheral blades rotatable within an annular gas passage 12 to be driven by axially flowing gases. 'I'he outer circumference of the passage 12 is defined by an outer shroud 13 comprising an annular section 14 overlying the rotor 10, an annular section l5 immediately downstream of the rotor 10, an annular section 16 defined by the housing of engine 9, and an annular section 17 overlying rotor 11. The inner periphery of the passage 12 is defined by an inner shroud 18 including an annular section 19 immediately upstream of rotor 10, an inner intermediate shroud comprising annular sections 2d and 21 arranged between the rotors l0 and 11, and an annular section 22 extending to the right of rotor 11.

An annular thickened portion 23 of the housing of engine 9 carries a plurality of circumferentially spaced and generally radially extending bushings 24 for a corresponding plurality of spindles 25. The upper end of at least one spindle 25 is flattened at 26 and is keyed to the hub 27 of a swinging arm 28 which terminates in a radially inwardly directed ball end 29. The latter is confined between a pair of generally radially and axially extending plates 30 carried by a ring 3l rotatable on a plurality of rollers 32. The latter are maintained by means of a suitable race 33 in circumferentially spaced relationship around a cylindrical portion 34 of the engine 9 coaxial with the rotors and 1l and ring 3l. A nut 35 is screwed on the radially outer end of spindle 25 tightly against hub 27 and the end of spindle portion 26 to maintain these elements in assembled position. Reference may be had to copending application Serial No. 34,296, led I une 6, 1960, for details of the nozzle adjustment mechanism.

The lower end of spindle 25 is secured to an adjustable nozzle part 38 arranged within passage l2 immediately upstream of the blades of rotor ll.. In the usual instance, twenty or more such nozzles 38 and associated spindles 25 are spaced circumferentially within the passage l2 with the nozzles 3S overlying the intermediate inner shroud section 21. Associated with each nozzle 38 and upstream thereof in the passage l2 is a fixed nozzle part 39 having its radially inner edge welded to the annular shroud section 20. The sections Ztl and 2i are detachably connected by means of a plurality of bolts dll. Batlle di completely closes the space within the shroud section Ztl to prevent axial ilow of gases therethrough.

A cylindrical recess 42, is formed within the shroud section 16 around the base of each spindle 25 to accommodate a split bushing comprising semi-circular parts t3 and 44 which extend around the spindle 25 at the region between the inner end of bushing Z4 and the nozzles 3S, 39. The bushing half 43 is suitably secured as by welding to the outer edge of fixed nozzle 39 and tits snugly within recess 42 around the upstream half of spindle 25. Bushing half 44 similarly fits snugly within recess l2 around the downstream side of spindle 25 so as to engage the bushing half i3 in force transmitting relationship and to cooperate therewith to provide a complete cylindrical bushing for the lower end of spindle 25. By the structure thus far described, lthe axially directed pressure forces of the motive gases in passage l2 acting on nozzle parts 39, and also the axially directed pressure forces against baille 4l, urging these elements to the right in FIGURE l, are carried by the ilxed nozzles 39 to the bushing halves 43 and are thence transmitted to the bushing halves dei. and to the outer shroud section le so as to shield the lower end of the spindle 25 from these forces.

As illustrated in FIGURES 5 and 6, the outer circumferential portions of the bushing halves 43 are formed to lie on a radius about the am's of the rotors l@ and il which is less than the minimum radius of the outer shroud 13 downstream of the spindles 25. Thus, prior to assembly of the spindles 25 and inner shroud section 2li, the shroud section Ztl with attached baille dl, xed nozzles 39, and bushing halves 43 can be assembled into position Ifrom the right in FlGURE 1 through the opening of the outer shroud 11.3. Thereafter the bushing halves 44% and also the spindles 25 with attached nozzles 3% are assembled from the inside of outer shroud i3, whereupon inner shroud section 2l is secured to shroud section 2d.

In order to accommodate for relative thermal expan sion between the inner and outer shroud sections, a clearance 46 is provided between the outer edge of nozzles 39 4and the juxtaposed portion of outer shroud section i6. Similarly, a clearance 47 is provided between the radially inner ends of bushings 24 and the juxtaposed bushing halves 43 and 44. In this regard, although the bushing halves 43 and 44 fit snugly within recess l2 so that axially directed forces applied to bushing half i3 are transmitted to bushing half 44 without causing a binding `action on spindle 25, the bushing halves 43 and 444 are slidable axially of their spindle 25 within recess 42 in the event of relative thermally induced `dinlensional changes.

I claim:

l. In a gas turbine engine having an annular Vgas passage deilned in part by outer and inner shrouds, a plurality of spindles extending generally radially through and journalled in said outer shroud at circumferentially spaced locations, an adjustable nozzle secured to the inner end of each spindle for pivoting therewith, a recess in said outer shroud around the inner end or each spindle, a bushing comprising two mating parts extending around each spindle and seated rmly against the walls of said recess in force transmitting relationship therewith, a ilxed strut connecting one part of each bushing with said inner shroud to transmit axial force from the latter to the associated one bushing part, said one bushing part engaging its mating part to transmit said axial force thereto and thence to the wall of the associated recess to shield said spindle from said force.

2. The combination according to claim l wherein said inner shroud comprises two coaxial end-to-end sections, said strut being secured to one of said sections, said one into assembled position within said outer shroud with section and associated one bushing part being insertable said one section coaxial with said outer shroud and with said one bushing part seated in said recess, each spindle with its nozzle attached and the associated other of said mating bushing parts being insertable radially into said outer shroud from the interior thereof prior to assembly of the other of said two shroud sections, and means for removably securing said other shroud section to said one shroud section after assembly oi said one shroud section, strut, two mating bushing parts, spindle, and nozzle.

3. The combination according to claim l wherein said outer shroud opens axially at one end in the direction of ilow of said motive gases; said inner shroud comprising two end-to-end sections detachably connected and coaxial with said outer shroud; one of said inner shroud sections being connected by said struts with said one of said bushing parts and each of the latter extending around the side of the associated spindle which faces oppositely from said direction; the maximum radial distance from the axis of said one inner shroud section to the radially outermost portions of said one bushing parts being less than the minimum internal radius of said outer shroud to enable assembly of said one inner shroud section and connected struts and one bushing parts from said one end prior to assembly of the associated other bushing parts, nozzles, and spindles; each spindle and associated nozzle and other bushing part being insertable radially into said outer shroud from said one end prior to assembly of the other of said two inner shroud sections; said other inner shroud section extending in juxtaposition with the inner edges of said nozzles and being dimensioned to be assembled to said one inner shroud section after assembly of the latter with the attached struts and one bushing parts and also after assembly of said nozzles, spindles, and other bushing parts.

4. The combination according to claim 3 wherein each of said one bushing parts is slidable within its associated recess in directions radially of its associated spindle to accommodate for thermal expansion and contraction of said inner shroud.

5. In a gas turbine engine having an annular gas passage detined in part by outer and inner shrouds, a plurality of spindles extending generally radially through and journalled in said outer shroud at circumferentially spaced locations, an adjustable nozzle secured to the inner end of each spindle for pivoting therewith, a recess in said outer shroud around the inner end of each spindle, a bushing comprising two mating parts extending around each spindle and seated rmly against the walls of said recess in force transmitting relationship therewith, a fixed nozzle associated with each adjustable nozzle and integral with one part of the associated bushing and with sa-id inner shroud to transmit axial force from the latter to the associated one bushing part, said one bushing part engaging its mating part to transmit said axial force thereto and thence to the wall of the associated recess to shield said spindle from said force.

`6. In a gas turbine engine having an annular gas passage dened in part by outer and inner shrouds, a plurality of spindles extending generally radially through and journalled in said outer shroud at circumferentially spaced locations, an adjustable nozzle secured to the inner end of each spindle for pivoting therewith, a recess in said outer shroud around the inner end of each spindle, a bushing comprising two mating parts extending around each spindle and seated firmly against the walls of said recess in force transmitting relationship therewith, a fixed nozzle associated with each adjustable nozzle and integral with one part of the associated bushing and with said inner lo 2412365 shroud to transmit axial force from the latter to the associated one bushing part, said one bushing part engaging 5 thermal expansion and contraction of said inner shroud.

References Cited in the le of this patent UNITED STATES PATENTS Marguerre Dec. 29, 1936 Sollinger Dec. 10, 1946 FOREIGN PATENTS Germany Feb. 28, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3yO59,902 October 23 1962 Giovanni Fo Savonuzzi lt is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line for vtberemally" read thermally column 4, lines I7 and 18, for "into assembled position within said outer shroud with section and associated one bushing part being insertable" read section and associated one bushing part being insertable into assembled position within said outer shroud with signed and sealed this 23rd day of April i9e3 (SEAL) Attest:

ERNEST w. swTDEE DAVID L LADD ttesting Officer Commissioner of Patents

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