US3074689A - Adjustable nozzle ring support - Google Patents

Description

Jan. 22, 1963 w. l. CHAPMAN ,5

' ADJUSTABLE NOZZLE RING SUPPORT Filed June 6, 1960 2 Sheets-Sheet 1 INVENTOR. WILL/17M I. CHAPMAN YHW $14M /7 T TOE/VEVS Jan. 22, 1963 w. I. CHAPMAN ,0

ADJUSTABLE NOZZLE RING SUPPORT Filed June 6, 1960 2 Sheets-Sheet 2 'INVEN TOR. MLL/flM I. C'H/IPMHN By FMAM Plum United States Patent O 3,074,689 ADJUSTABLE NOZZLE RING SUPPORT William I. Chapman, Birmingham, Mich, assignor to Chrysler Corporation, Highland Park, Mich, a corporation of Delaware Filed June 6, 1960, Ser. No. 34,296 '7 Claims. (Cl. 253-48) This invention relates to an adjustable nozzle assembly for a gas turbine engine.

In a common type of gas turbine engine, an annular conduit comprising inner and outer shrouds conveys hot motive gases to the peripheral blades of a coaxial rotor to drive the same. Within the conduit immediately in advance of the rotor blades are arranged a plurality of adjustable nozzles for adjusting the angle of attack of the motive gases against the rotor blades. Reference may be had to Huebner et al. Patent No. 2,795,928 for details of a gas turbine engine of the type with which the present invention is concerned.

Among the problems in the construction of such an engine is the provision of a simple mounting for the adjustable nozzles whereby the latter are unencumbered by either of the shrouds or conduit walls but are readily engageable by an exterior adjusting mechanism for selective adjustment thereby, regardless of relative thermal expansion between the parts.

An important object of the present invention is therefore to provide an improved highly elficient adjustable nozzle assembly for a gas turbine engine which avoids the above problem and which is particularly simple and economical to manufacture and assemble.

Another object is to provide such a nozzle assembly comprising a plurality of separate nozzle elements spaced circumferentially within the annular conduit upstream of the rotor. Secured to each nozzle element to pivot the same is a pivotal shaft or spindle journalled in the outer shroud and extending generally radially with respect to the common axis of the rotor and annular conduit. The outer end of each shaft is secured to a swinging arm to be pivoted thereby upon swinging of the arm. Also adjacent the nozzle elements, the outer shroud is formed to provide a cylindrical support coaxial with the rotor and facing radially outwardly. A ring is rotatably mounted coaxially on the support and is engageable with the swinging ends of the several arms to swing the same upon rotation of said ring.

In operation of such a structure, the hot motive gases in the conduit results in appreciable thermal expansion and distortion of the cylindrical support for the ring, tending to bind the latter and to cause erratic operation of the nozzle adjustment. Other objects are accordingly to provide an improved interconnection between the ring and arms and to provide an improved bearing means between the ring and support which readily accommodates relative thermal expansion between the ring and support and the consequent deformation of these elements without impairing their relative adjustability and without introducing undesirable play or lost motion in the system.

Another and more specific object is to provide such a structure wherein the ring is provided with a plurality of radially opening slots, each extending axially of the ring and closely confining the swinging end of one of each of said arms to swing the latter upon rotation of the ring.

Another object is to provide a ring of the above character of resilient material and of somewhat larger diameter than the cylindrical support, and to provide bearing means between the ring and support comprising a plurality of circumferentially spaced rollers engaging the support and ring at widely spaced locations, so that upon ice relative thermal dimensional changes between the support and ring, the latter will be deformed resiliently to the necessary out-of-round condition to accommodate for the relative dimensional changes while maintaining rolling contact between the ring and rollers.

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 1 is a fragmentary mid-sectional view through a two-stage gas turbine engine embodying the present in vention, taken along the common axis of the engines rotors and showing details of the mounting for one of the adjustable nozzles.

FIGURE 2 is a fragmentary sectional view taken in the direction of the arrows substantially along the line 2-2 of FIGURE 1.

FIGURE 3 is a fragmentary sectional view taken in the direction of the arrows substantially along the line 3-3 of FIGURE 1.

FIGURE 4 is a fragmentary view taken in the direction of the arrows substantially along the arcuate line 4-4- of FIGURE 3.

FIGURE 5 is a reduced fragmentary sectional view through the nozzle actuating ring and its cylindrical sup port and roller mounting, taken in the direction of the cylindrical axis.

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 and particularly to FIGURE 1, a gas turbine engine embodying the present invention is illustrated comprising a housing indicated generally by the numeral 9 which carries first and second stage rotors arranged coaxially in tandem. Only a portion of the second stage rotor 11 is illustrated herein. A typical automotive gas turbine engine of the type with which the present invention is concerned is illustrated in detail in the aforesaid Heubner et al Patent No. 2,795,928, it being sufiicient to state herein that pressurized combustion supporting air is discharged from an engine driven compressor, preheated by a regenerator, admixed with fuel which is burned in a combustion chamber to supply the driving energy, and then conveyed into an annular conduit 21 coaxial with the rotors and defined by inner and outer shrouds 22 and 23. Conduit 21 conveys the combustion products first to the blades of the first stage rotor, then to the peripherally disposed blades 25 of rotor 11 to drive the corresponding rotors, then by way of collecting chamber 36 to'the regenerator, not shown, to heat the same.

The gas driven rotor 11 is secured to a coaxial shaft 39 journalled in a bearing portion 9a of housing 9 and is connected by a speed reducing gear train with the vehicle wheels to propel the same. Upstream of rotor 11 is a diaphragm 42 which completely seals the interior of the shroud 22 against axial flow of gases between the two rotor stages to prevent bypassing of the first rotor stage by the motive gases. The peripheral portions of diaphragm 42 are closely fitted into a notch within a radially inturned flange 22a ofan annular section of the inner shroud 22 which is secured by bolts 43 to a correspondingly inturned flange 22b of an annular section 22c of the inner shroud 22. Upstream of rotor 11, shroud section 220 terminates adjacent the roots of the rotor blades 25 and cooperates with an annular terminal section 22d of the inner shroud 22 located downstream of the rotor 11 to complete the inner shroud assembly. A radially inturned annular flange 222 of shroud section 220! tightly engages the outer periphery of an annular inner diaphragm 44 which closes the interior of the inner shroud 22 downstream of rotor 11. The inner circumference of diaphragm 44 extends closely to the cylindrical portion 9a of the engine housing within which the rotor shaft 39 is journalled and is secured to the annular base 45 of a plurality of radial struts 46. Three such struts in the present instance extend through and are secured to the inner shroud section 22d to support the same.

The outer shroud 23 includes an annular section 23a supported on the outer peripheral edges of a plurality of circumferentially disposed fixed interstage nozzle blades 48 secured to and supported by a section of the inner shroud 22. Downstream of the shroud section 23a and substantially continuous therewith is an annular outer shroud section 23b having an annular reinforcing flange 23c overlying shroud section 23a and also having a radially extending annular outer boss 23d and flange 23c secured as for example by bolts 49 to bracket elements 9c and 9d respectively of the engine housing. Suitable bulkheads 9e, 9 and 9g of the engine housing connected to the bracket portions 9c and 9d reinforce the housing structure, the bulkhead 9g also defining an inner wall of chamber 36.

The outer shroud section 23b terminates adjacent the outer periphery of the rotor blades 25 in juxtaposition with an annular outer shroud section 231 having a radial flange 23g secured by means of bolts 50 to a cooperating radial flange 23h of an annular outer shroud section 231'. Shroud section 23i is secured to the outer ends of the struts 46 and overlies an annular terminal shroud section 23 to complete the outer shroud assembly 23. The complete inner shroud assembly 22 includes the various flanges and sections 22a through 2212 cooperating to provide a substantial continuous inner wall for the annular gas passage 21. Similarly the complete outer shroud assembly 23 includes the various flanges and outer shroud sections 23a through 23 cooperating to provide a substantially continuous outer wall for the conduit 21. The plurality of circumferentially spaced interstage fixed nozzles 48 in conduit 21 downstream of blades 25 space the associated portions of the shrouds 22 and 23 and direct the flow of motive gases to a plurality of circumferentially arranged adjustable nozzles 55 arranged immediately upstream of rotor blades 25 as described below.

Extending in the shroud boss 23:! generally radially with respect to the axis of rotor 11 and spaced circumferentially around the latter is a plurality of bores 51 for a corresponding plurality of tubular bushings 52 snugly pressed into the bores 51 in fluid sealing relationship therewith to prevent radial leakage of motive gases from conduit 21 between the juxtaposed portions of each of the bushings 52 and boss 23a. Journalled coaxially within the bore of each bushing 52 is a pivotal shaft 53 having an integral coaxial annular enlargement or seat 54 at its lower end seated within a restriction 51a of bore 51 and against the inner end of bushing 52 to provide a fluid tight seal therewith entirely around the circumference of shaft 53. Inwardly of the enlargements 54, each shaft 53 is integrally secured to one of each of the adjustable nozzles 55. T wenty-three such nozzles are provided in the present instance, each being pivotal upon pivoting of the associated shaft 53 so as to vary the angle of contact between the motive gases in conduit 21 and the blades 25.

The upper end of each shaft 53 is formed with a reduced portion 56 of square cross section, FIGURE 2, on which is splined the hub 57 of a swinging arm 58. Above the square section 56, an annular groove 59 is formed in an upper cylindrical portion 60 of shaft 53 having a Groove 59 contains a cupped C-shaped spring Washer 61 under compression against the upper face of the hub 57 to urge shaft 53 upwardly and hub 57 downwardly with respect to each other in FIGURE 1. Thus the annular seat 54 is maintained in sealing relation with the inner end of bushing 52 and the hub 57 is held in seated position against the upper end of bushing 52. By this arrangement, each nozzle or blade 55 is. maintained positively and firmly in its desired position within the conduit 21 and is readily pivotal upon pivoting of shaft 53, but fluid leakage from conduit 21 radially outwardly along shaft 53 is prevented by the annular seal 54 engaging the lower end of bushing 52.

Also comprising a portion of shroud boss 23a is a radially outwardly facing cylindrical bearing support 62 coaxial with the rotor 11 and annular conduit 21. A plurality of rollers 63 ride on the cylindrical surface of support 62 and are maintained in circumferentially spaced relationship by a retaining race 64, FIGURES 3 and 5, comprising a sheet metal ring stamping coaxial with the cylindrical support 62 and having a plurality of circumferentially spaced slots 65 loosely confining one of each of the rollers 63 therein. In order to maintain the slots 65 near the axes of the rollers 63, the lateral edges of the cage 64 are bent inwardly at 66 so as to ride on support 62, FIGURE 1.

Freely journalled on the rollers 63 coaxially with the cylindrical support 62 is a ring 67 of larger diameter than support 62 and having a plurality of pairs of brackets 68 and 69, FIGURES 3 and 4, corresponding to the number of nozzles 55. The brackets 68 and 69 of each pair are provided with footings 68a and 69a respectively welded to the outer circumference of the ring 67 in spaced relationship to provide a radially outwardly opening slot 70 to confine the terminal ball end 71 of one of each of the swinging arms 58 therein.

As indicated in FIGURE 1, the annular conduit 21 upstream of rotor 11 at the region of the nozzles 55 diverges axially downstream. The axis of shaft 53 extends generally radially to the axis of rotor 11 but at a slight angle determined by the angle of axial divergence of conduit 21. Thus the axis of shaft 53 extends perpendicularly to conduit 21 at the region of the chem-- ferentially spaced nozzle blades 55. Each arm 58 when aligned with an axial plane of the rotor 11 extends parallel to the adjacent portion of the conduit 21. Accordingly the outer edges of the brackets 68 and 69' are inclined correspondingly.

Overlying one of the pairs of brackets 68 and 69 is a yoke 72 having footings 73 welded to the outer surface of the ring 67. A radially outer portion of yoke 72 is pivotally secured to a reciprocable actuating lever 74. Upon reciprocation of lever 74, ring 67 is rotated in one direction or the reverse about the axis of support 62 so as to carry the ball ends 71 and swing the several arms 58 and associated nozzle spindles 53 simultaneously. The latter are thus pivoted to adjust the angular position of the nozzles 55 in unison with respect to the blades 25 as desired. In this action, the ball ends 71 are free to slide axially in their respective slots 70 as the ring 67 rotates and the arms 58 swing about the axes of their respective shafts 53.

The inner and outer ends of the nozzle blades 55 are shaped spherically about radii extending along the axes of their associated spindles 53 and centered at the intersection of those radii on the axis of the rotor 11. correspondingly, at the regions of the blades 55, the juxtaposed portions of the outer shroud section 23b and inner shroud section 220 are formed spherically about radii similarly centered. Thus upon pivotal adjusting movement of the blades 55, the clearance between their inner and outer edges and the adjacent inner and outer shroud sections will remain the same.

During operation of the engine, the hot motive gases in conduit 21 heat the adjacent shroud section 23b, which conducts the heat through boss 23d to the cylindrical support 62 and causes differential expansion of the latter with respect to the ring 67, depending on their relative temperatures and their coefficients of thermal expansion. Without some provision to the contrary, ring 67 would either bind on the rollers 63 and render its rotatable adjustment on support 62 difficult, or would become so loose as to result in excessive play or lost motion. In either event, ring 67 and its journal mounting would be subject to excessive wear and the angular adjustment of the several nozzles 55 would be erratic.

In order to avoid such difliculties, ring 67 is formed from comparatively thin resilient metal adapted to deform resiliently within the maximum temperature extremes that the engine might encounter. The rollers 63 are limited to a few members widely spaced uniformly around the circumference of the support 62 and maintained in their spaced relationship with respect to each other by the cage 64. In the present instance, only three such rollers spaced 120 apart are employed, FIGURE 5, so that the 120 arcuate portions of ring 67 between the rollers 63 can readily flatten slightly upon relative shrinking of the diameter of ring 67 with respect to the diameter of support 62. The rollers 63 closely engage the inner cylindrical surface of ring 67 in rolling contact and normally deform the same resiliently to a slightly out-of-round condition (flattened between rollers) so as to rotatably support the ring 67 without unusual play or lost motion and also without binding the same.

The support 62 and ring 67 will ordinarily be made of materials having different coefficients of thermal expansion. Also during a given change in engine temperature, the support 62 and ring 67 will ordinarily be subject to different increments of temperature change. Changes in engine temperature thus result in relative dimensional changes between the diameters of support 62 and ring 67. For example, in one instance depending upon the coefficients of expansion of the materials used, a certain increase in engine temperature will cause ring 67 to expand to a greater extent than support 62, in which case ring 67 will return resiliently to a more rounded condition. The use of other materials will result in a smaller expansion of ring 67 with respect to support 62, so that during the aforesaid increase in engine temperature, ring 67 will be forced resiliently to a more out-of-round condition. In either situation, by suitably predetermining the extent of the out-of-round deformation of ring 67 at one engine operating temperature, undesired play or lost motion between support 62 and ring 67 is prevented and a snug rolling engagement therebetween is achieved for all operating temperatures, the out-of-round deformation of ring 67 resiliently increasing or decreasing as its relative diameter decreases or increases with respect to the diameter of support 62. At the maximum, ring 67 will ordinarily be ten to twenty thousandths of an inch out-of-round, so that the flattening of its circumferential portions between rollers 63 is not distinguishable in FIGURE 5.

-I claim:

1. In a gas turbine engine, a rotor, an annular conduit comprising inner and outer shrouds coaxial with said rotor for conveying motive gases thereto to drive the same, adjustable nozzle means for varying the angle of contact between said rotor and the flow path of said gases, said nozzle means including a plurality of circumferentially spaced nozzle elements within said conduit, a pivotal shaft connected with each nozzle element to swing the same upon pivoting of the shaft, each shaft extending generally radially with respect to the axis of said rotor and being journalled in said outer shroud for pivoting on the axis of the shaft, said outer shroud having a cylindrical support coaxial with said rotor and facing radially outwardly, a continuous flexible resiliently deformable ring of larger diameter than said support and coaxial therewith, bearing means interposed between said support and ring to rotatably carry the latter, said bearing means including a plurality of rollers widely spaced circumferentially around the periphery of said support, means for holding said rollers in circumferentially spaced relationship, and means interengaging said ring and each of said shafts to pivot said nozzles in unison upon rotation of said ring around said support, the circumferential curvature of said ring being resiliently flattened between said rollers to an outof-round shape and being susceptible of resiliently increasing or decreasing its out-of-round deformation to maintain a snug bearing support for said ring and to eliminate lost motion between said ring and support during the thermally induced dimensional changes of said support and ring during operation of said engine, and said ring being sufficiently flexible to prevent binding of said hearing means when said ring is subject to its maximum outof-round deformation.

2. In a gas turbine engine, a rotor, an annular conduit comprising inner and outer shrouds coaxial with said rotor for conveying motive gases thereto to drive the same, adjustable nozzle means for varying the angle of contact between said rotor and the flow path of said gases, said nozzle means including a plurality of circumferentially spaced nozzle elements within said conduit, a pivotal shaft connected with each nozzle element to swing the same upon pivoting of the shaft, each shaft extending generally radially with respect to the axis of said rotor and being journalled in said outer shroud for pivoting on the axis of the shaft, said outer shroud having a cylindrical support coaxial with said rotor and facing radially outwardly, an annular resilient ring of larger diameter than said support and coaxial therewith, bearing means interposed between said support and ring to rotatably carry the latter, said bearing means including a plurality of rollers widely spaced circumferentially around the periphery of said support, means for holding said rollers in circumferentially spaced relationship, and means interengaging said ring and each of said shafts to pivot said nozzles in unison upon rotation of said ring around said support, the outer circumferential surface of each roller being in rolling contact with both said ring and support to carry the force exerted by the resiliently deformed ring and to transmit said force to said support, the circumferential curvature of said ring being resiliently flattened between said rollers to an out-of-round shape and being susceptible of resiliently increasing or decreasing its out-of-round deformation to maintain a snug bearing support for said ring and to eliminate lost motion between said ring and support during thermally induced dimensional changes of said support and ring during operation of said engine, and said ring being sufficiently flexible to prevent binding of said bearing means when said ring is subject to its maximum out-of-round deformation.

3. In a gas turbine engine, a rotor, a conduit for conveying motive gases to said rotor, a plurality of adjustable nozzle means spaced circumferentially around the axis of said rotor for varying the angle of contact between the latter and the flow path of said gases, said conduit having a cylindrical support coaxial with said rotor, a continuous flexible resiliently deformable ring coaxial with said support, bearing means interposed between said support and ring to rotatably mount the latter on said support, said bearing means including a plurality of rollers Widely spaced around the circumference of said support, means maintaining said rollers in said spaced relationship, means interengaging said ring and each nozzle means to adjust the latter upon rotation of said ring around said axis, said ring being resiliently deformed by engagement with said rollers to an out-of-round shape and being susceptible of resiliently increasing or decreasing its out-ofround deformation to maintain a snug bearing support for said ring and to eliminate lost motion between said ring and support during thermally induced dimensional changes of said support and ring during operation of said engine, and said ring being sufiiciently flexible to prevent binding of said bearing means when said ring is subject to its maximum out-of-round deformation.

4. In a gas turbine engine according to claim 3, the outer circumferential surface of each roller being in rolling contact with both said ring and support to carry the force exerted by the resiliently deformed ring and to transmit said force to said support.

5. In a gas turbine engine according to claim 3, each nozzle means including a nozzle element in said conduit, and a pivotal shaft secured to the nozzle element to pivotally adjust the latter and being journalled in the wall of said conduit, and said means interengaging said ring and nozzle means including a separate swinging armsecured to each shaft to pivot the latter, said ring carrying a radially opening and axially extending slot associated with each swinging arm and having the swinging end of the associated arm closely confined therein to swing the arm upon rotation of said ring, each slot being axially disposed from the shaft secured to its associated arm.

6. In a gas turbine engine according to claim 3, said bearing means including three rollers equally spaced around said circumference of said support, the outer circumferential surface of each roller being in rolling contact with both said ring and support to carry the force exerted by the resiliently deformed ring and to transmit said force to said support.

7. In a gas turbine engine according to claim 3, said bearing means including three rollers equally spaced around said circumference of said support, each nozzle means including a nozzle element in said conduit, and a pivotal shaft secured to the nozzle element to pivotally adjust the latter and being journalled in the wall of said conduit, and said means interengaging said ring and nozzle means including a separate swinging arm secured to each shaft to pivot the latter, said ring carrying a radially opening and axially extending slot associated with each swinging arm and having the swinging end of the associated arm closely confined therein to swing the arm upon rotation of said ring, each slot being axially disposed from the shaft secured to its associated arm.

References Cited in the file of this patent UNITED STATES PATENTS 2,671,634 Morley Mar. 9, 1954 2,819,732 Paetz Jan. 14, 1958 2,862,654 Gardiner Dec. 2, 1958 2,976,015 Gilbert Mar. 21, 1961 OTHER REFERENCES NACA Research Memorandum B52603 of 1952, FIG- URE 4.

Claims (1)

1. IN A GAS TURBINE ENGINE, A ROTOR, AN ANNULAR CONDUIT COMPRISING INNER AND OUTER SHROUDS COAXIAL WITH SAID ROTOR FOR CONVEYING MOTIVE GASES THERETO TO DRIVE THE SAME, ADJUSTABLE NOZZLE MEANS FOR VARYING THE ANGLE OF CONTACT BETWEEN SAID ROTOR AND THE FLOW PATH OF SAID GASES, SAID NOZZLE MEANS INCLUDING A PLURALITY OF CIRCUMFERENTIALLY SPACED NOZZLE ELEMENTS WITHIN SAID CONDUIT, A PIVOTAL SHAFT CONNECTED WITH EACH NOZZLE ELEMENT TO SWING THE SAME UPON PIVOTING OF THE SHAFT, EACH SHAFT EXTENDING GENERALLY RADIALLY WITH RESPECT TO THE AXIS OF SAID ROTOR AND BEING JOURNALLED IN SAID OUTER SHROUDS FOR PIVOTING ON THE AXIS OF THE SHAFT, SAID OUTER SHROUD HAVING A CYLINDRICAL SUPPORT COAXIAL WITH SAID ROTOR AND FACING RADIALLY OUTWARDLY, A CONTINUOUS FLEXIBLE RESILIENTLY DEFORMABLE RING OF LARGER DIAMETER THAN SAID SUPPORT AND COAXIAL THEREWITH, BEARING MEANS INTERPOSED BETWEEN SAID SUPPORT AND RING TO ROTATABLY CARRY THE LATTER, SAID BEARING MEANS INCLUDING A PLURALITY OF ROLLERS WIDELY SPACED CIRCUMFERENTIALLY AROUND THE PERIPHERY OF SAID SUPPORT, MEANS FOR HOLDING SAID ROLLERS IN CIRCUMFERENTIALLY SPACED RELATIONSHIP, AND MEANS INTERENGAGING SAID RING AND EACH OF SAID SHAFTS TO PIVOT SAID NOZZLES IN UNISON UPON ROTATION OF SAID RING AROUND SAID SUPPORT, THE CIRCUMFERENTIAL CURVATURE OF SAID RING BEING RESILIENTLY FLATTENED BETWEEN SAID ROLLERS TO AN OUTOF-ROUND SHAPE AND BEING SUSCEPTIBLE OF RESILIENTLY INCREASING OR DECREASING ITS OUT-OF-ROUND DEFORMATION TO MAINTAIN A SNUG BEARING SUPPORT FOR SAID RING AND TO ELIMINATE LOST MOTION BETWEEN SAID RING AND SUPPORT DURING THE THERMALLY INDUCED DIMENSIONAL CHANGES OF SAID SUPPORT AND RING DURING OPERATION OF SAID ENGINE, AND SAID RING BEING SUFFICIENTLY FLEXIBLE TO PREVENT BINDING OF SAID BEARING MEANS WHEN SAID RING IS SUBJECTED TO ITS MAXIMUM OUTOF-ROUND DEFORMATION.

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