US3189261A - Bladed rotor for fluid machines - Google Patents

Description

June 15, 1965 E. A. STALKER 3,139,261

BLADED ROTOR FOR FLUID MACHINES Original Filed Feb. 14, 1957 3 Sheets-Sheet 1 7 -83 ul X 7 i 7 :8 x

. 8 42 40 mv/\\\\ 30- I i 76 82 i 26 I 36 I H 96 mvzm-on WE --4 EDWARD A. STALKER ATTORNEYS WWW June 15, 1965 T KE 3,189,261

BLADED ROTOR FOR FLUID MACHINES Original Filed Feb. 14, 1957 3 Sheets-Sheet 2 /O I 1 F u 7 .2 9'. 2 n n i INVENTOR EDWARD A. STALKER ATTORNE S June 15, 1965 E. A. STALKER 3,139,261

' BLADED ROTOR FOR FLUID MACHINES Original Filed Feb. 14, 1957 3 Sheets-Sheet 3 INVENTOR EDWARD A. STALKER BY E M MMM a ATTORNEYS United States Patent 3,189,261 BEADED RUTOR FUR FLUED MACHINES Edward A. Stalker, Bay Elity, Mich, assignor to Stalker Development (Iornpany, Bay City, Mich, a corporation of Michigan Uriginal application Feb. 14, 1957, Ser. No, 640,13'7, now- Patent No. 3,d91,383, dated May 28, 1963. Divided and this appiieation Lian. 9, 1%3, Ser. No. 250,409 4- Clairns. (til. 230-122) This invention relates to rotor constructions for compressors, turbines and the like. This application is a division of my copending application Serial No. 640,197, filed February 14, 1957, now Patent No. 3,091,383.

An object of this invention is to provide a low cost bladed rotor for axial fiow machines.

Another object is to provide a simple and economical means of fastening blades in a rotor.

A further object is to provide a bladed rotor which effects a large saving in the weight of the rotor rim.

Another object is to provide a rotor with economical disengageable blades.

Still another object is to provide a light weight and economical rotor with blades brazed in place.

These objects are accomplished by the means illustrated in the accompanying drawings in which FIG. 1 is a side elevation of a gas turbine powerplant incorporating structures according to this invention;

FIG. 2 is a fragmentary axial section through the compressor of the powerplant of FIG. 1;

FIG. 3 is an enlarged fragmentary section of a rotor of FIG. 2;

FIG. 4 is an axial view of a rotor and a cylindrical spacer in section;

FIG. 5 is a fragmentary view of the rotor rim and the blades on section line 55 of FIG. 3;

FIG. 6 is an axial view of a fragment of the blade support disk at its perimeter; 7

FIG. 7 is a fragmentary section on line 7-7 of FIG. 3;

FIG. 8 is a fragmentary section on line 8-8 of FIG. 3;

FIG. 9 is a fragmentary axial section of the compressor incorporating an alternate means of fastening blades in the rotors;

FIG. 10 is an axial view of a rotor of the compressor of FIG. 9;

FIG. FIG. 10;

FIG. 12 is an axial view of a fragment of a support disk with a portion of a blade secured thereto;

FIG. 13 is a fragmentary section on line 1313 of FIG. 11;

FIG. 14 is a fragmentary section on line 14-14. of FIG. 11;

FIG. 15 is a broadside view of a blade for the rotor of FIG. 9;

FIG. 16 is a section on line 16-16 of FIG. 15;

FIG. 17 is a fragmentary section on line 17-47 of FIG. 15; and

FIG. 18 is a fragment of another rotor showing the attachment of the blades to the hub structure.

In certain types of turbine powerplants, thosefor auto- 11 is a fragmentary section on line 1111 of motive vehicles for instance, low initial cost of the powerplant is more important than low weight. This resuit is achieved in this invention in part by providing for securing the blades of the rotors in the rotor hub structure by mechanical means, or by providing economical blades with economical fastening means at their inner ends.

Also in this invention a rotor structure is provided which can be fabricated by low cost machine operations such as turning and/ or pressing with dies, sometimes called stamping, but herein included along with punching in the general term pressing. Turning as by a Patented June 15, 1%65 lathe is a very economical operation as compared to other cutting-machine operations. If the fastening means for blades in a rotor can be made by a simple lathe operation, or by such operation in combination with a pressing operation (for instance punching of a hole) there is great saving in cost as compared to forming an axial slot in a rotor hub rim and shaping a blade root end to fit the slot properly. In this invention the blade support disk can have its blade attachment elements turned therein by an automatic lathe and the blade may have proper projections and recesses pressed therein. An attachment employing these features is then accomplished at relatively low cost.

The blade support disk may be cut from plate or sheet stock by dies operated in a punch press. Likewise the side disks may be made by punch press operations. Holes in the parts may either be punched or drilled, both being simple economical operations. rolled by dies in long strips and subsequently cut to blade lengths. Such strips or lengths may have like blade sections along their spans.

Another feature of this invention is that the blades are preferably supported against centrifugal force at localities spaced inward from the rim means where they are supported against bending loads. Each blade passes through the opening in the rim means and retains its full cross sections adjacent the rim means. That is, the blade is preferably free of notches and indentations whichwould tend to cause stress concentrations.

Also in this invention the blades may be fixed to the side disks by brazing the blade projections in their respective holes in the side disks. This is particularly important when the side plates are made of thin sheet metal.

Referring now to the drawings, FIG. 1 shows a gas turbine engine indicated generally as If). It comprises the compressor 12, the combustor 14 and turbine 16.

The compressor, FIGS. 1 and 2, employs a rotor assembly 18 comprising a plurality of rotors 19-22, such rotors being of similar construction and a typical rotor 20 being shown enlarged in FIGS. 3 and 4. It comprises a plurality of blades 26 and the rotor hub means 24. The stator blades are denoted generally as 25..

Each blade may have the same blade section from its inner end to its tip which is spaced radially outward from the hub means. Such blades are produced cheaply by rolling between dies formed in one or more rolls. Long strips may be rolled and the proper lengths of blades cut from it.

As shown particularly in FIGS. 35 the blades 26 are spaced peripherally and have their spans extending in the general radial directions. Their chords extend substantially normal to the spanwise or radial direction. Each blade extends radially inward through cooperating openings 30 formed in each half of rim means 32 of the rotor hub means. Preferably each blade is articulated to the blade support disk 36 comprised in the hub'means which also includes radial Walls or plates which are axially spaced and extend transversely of the rotor axis. These walls may be annular or substantially complete disks.

As shown in FIG. 3 particularly, each blade is secured mechanically to the support disk 36. The fastening means securing each blade includes a securing means or tongue 42 on the disk and an aperture 41) in each blade near the inner end portion thereof. The tongue 42 on the support disk near its perimeter projects through each aperture to mechanically secure the blade against centrifugal force acting on it when the rotor is spun about the axis of shafts 46, 47. i it Each blade is inserted as indicated in FIG. 6 starting with positions shown in dotted lines and ending with the radial position shown in full lines. The inner end of the blade fits into the recess 52 and when the blade is posi- The blades may be.

tioned by the rim walls defining the openings or notches 30, the inner end cannot be moved out of the position in the recess 52. Thus the blade though articulated to the disk is restrained from relative movement.

The rotor blades are preferably first assembled on the support disk 36. Then a side plate, preferably rear plate 70 for instance, is added and if desired may be fixed by spot welds 74. Each blade is inserted in the notch in the rim wall. This positions the blades with the proper pitch angle. Next the other plate, i.e. front plate 76, is added. The support disk and side plates may be fixed together as by welding but preferably they are disengageably connected either as a single assembly or when integrated into the rotor assembly comprising a plurality of rotors. They may be fixed together by bolts 80 which may be removed at the time of assembling into the rotor assembly 18.

Projections 79 and 81 respectively at front and rear sides of the blades may be present as shown in FIG. 3. They may bear against the outer edges of the openings in the side disks to sustain part of the centrifugal load coming from rotation of the blades about the rotor axis. These projects also position the inner ends of the blades and sustain the bending loads which are substantially normal to the broad sides of the blades.

The side plates 70, 76 are preferably dished or conical over substantial radial dimensions so that centrifugal forces arising from their high speed rotation in use tend to force the outer portions of the disks toward each other. The inner portions of the plates are preferably flat and paralled to fit against the support disk 36. The outer portions of the plates diverge one relative to the other outward along the radial directions to form the conical portions.

The rim means preferably comprises the flanges 32, 32 each integral with one of side plates 70, 76 and extending axially toward each other to close the gap between the blades.

The rim means flanks each blade to support it against lateral forces thereon and closes the space between blades to provide surfaces for guiding the compressed fluid between the blades from the front to the rear of the rotor.

To avoid stress concentration at the locality on each blade opposite the rim flanges, a fillet means 82 is inserted between each blade and the adjacent portions of the flanges 32. This means comprises an element on each side of the blade of wedge like form to press against the blade and rim under the action of centrifugal force. As clearly shown in FIG. 7, the fillet elements 82 are received inwardly of the flanges 32 and extend through the blade openings radially outwardly, and are substantially wider at the portion inwardly of the flanges than at the portion extending radially outwardly thereof. The portions of the elements just outside the flanges having an outer surface of concave shape as indicated at 82' and therefore are curved and tapered to provide a fillet function for the blade at the flanges where the bending loads on the blade are the greatest. Thus, as shown at 82', the outer surfaces of the fillet elements flare into the blade surface outwardly of the rim flange and also substantially flare with the outer surface of the flange 32. The fillet elements are kept from falling radially inward by the cotter pins 83.

A rotor securing means, FIGS. 2 and 3, fixes the rotors in the rotor assembly. It comprises end pieces 90 and 92 with the hollow cylindrical spacers 96 between adjacent rotors and bearing on the portions of the disk preferably at the locality where the disks begin to diverge one from the other. Tie rods 98 extend through the series of spacers and matching holes in the disks and are secured in the end pieces 90, b2.

It is a marked advantage costwise to have the blades initially of constant blade section. The short lengths of blades can be cut by dies to provide the tapered end portion and the holes 40 for securing each blade to the support disk 36. These are essentially punch press operations and can be executed by automatic machines at small cost.

In another form of the invention each blade 26, FIGS. 9-17 has an opening formed in the central portion of its inner end defined by projections 112 which fit into the circular recesses formed in the support stubs 114 of the support disk 116. The gaps 118, FIG. 12, between the stubs permit each blade to be slid onto its respective stub in disengageable relation thereto.

The blades are restrained from sliding along the recesses in the disk by the lugs 122 and 124, FIGS. 10 and 11, which project in the general chordwise direction from the front and rear sides of the blades through holes in the side disks 70 and 76. Thus the lugs cooperate with the rim means 32' in supporting the blades against bending loads such as the fluid loads coming on their broad sides.

The holes receiving the lugs are spaced inward from the rim means so that there is ample material radially outward of each hole to provide a strong abutment for each lug to sustain centrifugal loads from the blades. Since the disks are integrally continuous in the material radially outward of the holes the peripherally directed stresses are sustained effectively. The rim means 32' likewise is peripherally integral with the side plates to aid in sustaining peripheral stresses.

Each disk is preferably punched from sheet or plate stock to cut out the material between the support stubs. The recesses in the stubs are preferably circular so that they are produced cheaply by turning, or by dies which are produced cheaply. Thus the blades are secured cheaply and lightly.

The blades are preferably thickened somewhat at their inner ends 12% (FIGS. 16 and 17) to provide a fillet outwardly adjacent the rotor rim. However the thickness of this end is small relative to the peripheral gap between blades measured at the rim. With such proportions the blade is economically produced, for instance by rolling or die forging.

The main body of the blades is Preferably quite thin, less than about 12% of the chord length and of short chord length so that the blades are relatively light in weight adapting them to be sustained by relatively simple and light fastenings. Preferably, the chords are less than one-half the blade spans outside the rotor rims.

The blade may also be cut and formed from sheet stock. This is an economical method of producing blades incorporating the lugs and opening means. The leading and trailing edges are easily and economically faired.

This invention also presents the advantage that the parts may be heat treated individually to high strengths. For instance the side disks 70 and 76 may be of high carbon steel or an inexpensive alloy steel, either of Which may require liquid quenching from a high temperature to develop high strength. These parts may be heated and quenched individually after which they may be sized in a die if any warpage has occurred. If the parts of the whole rotor were assembled in permanent or fixed relation it would be difficult to heat treat and quench without warpage and difiicult to eliminate the warpage if it occurred. Another advantage is that different parts can be given different heat treatments.

The rotor construction of this invention is also useful for the rotors of the turbine 16.

The blades may be sustained against centrifugal force entirely by the lugs 122 and 124 by their proper design and the proper design of the side disks. If for instance the weight of the structure is significant as in aircraft uses the side plates may be made from thin sheet metal with the lugs brazed in position along the surfaces at the holes into which the lugs fit. In this instance brazing is significant in transferring the blade loads to the thin sheet and preventing galling of the lugs against the sides of the holes.

The invention is particularly adapted to the construction of axial flow compressors. These machines are characterized by passages defined between adjacent blades and the rim and case, which passages have cross sectional areas at their exits (rear sides) greater than at their inlots. There is a substantial static pressure rise in the passages and the rims must extend from blade to blade and from front to rear thereof to sustain the rise in pressure. The front portions of the blades also point in the general direction of rotation.

It will now be clear that I have disclosed a novel rotor which is adapted to fabrication by simple tools leading to a low cost of construction. The invention also discloses simple means securing the blades to the rotor disks or plates. This means is particularly useful if the blades are to be disengageable. However the blades can cooperate with the rotor disks to provide an arrangement wherein the blades are brazed to the disks.

The means of securing the blades to the rotor eliminates the use of a heavy rotor rim to receive the blades and eliminates expensive blade bases.

While the forms of apparatus and the process herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus and process, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

FIG. 18 is a fragmentary section of a rotor wherein each blade 150 is mechanically sustained by lugs 151 and 152 positioned in openings in the side plates 154. The blade has the thickened root portion 126 (as shown in FIG. 17) extending throughout the lugs to increase their strength. The central support disk 156 terminates short of the blade and outwardly of the clamping devices such as 96 and 98 which serve to hold the side disks together.

What is claimed is:

1. In combination in an axial flow compressor a compressor case means, a rotor assembly mounted in said case means for rotation about the rotor axis, said as sembly comprising a plurality of rotors positioned in tandem, each said rotor comprising a blade means including a radially extending support disk and a plurality of axial flow blades disengageably secured thereto, said blades being peripherally spaced about said support disk and extending outward in the general radial direction, axially spaced side plates on opposite sides of said support disk faying said disk along an inner radial extent thereof, said plates having an outer generally radial portion diverging axially outwardly and terminating at a rim means extending axially to opposite sides of said blades, and disengageable connecting means connecting said plurality of rotors together in spaced relation including tie rods passing through said support disk and the side plates radially inwardly of said diverging portion of each said rotor disengageably securing said assembly together.

2. The combination of claim 1 wherein each of said blades includes a strain relieving metal fillet retained thereon against radial inward movement and movable free of said blades radially outward under centrifugal force of said blades into engagement with said rim means 6 with a portion thereof extending adjacentthe associated blade radially outwardly of said rim means.

3. In combination in an axialflow compressor a compressor case means, a rotor assembly mounted in said case means for rotation about the rotor axis, said assembly comprising a plurality of rotors positioned in tandem, each said rotor comprising a blade means including a radially extending support disk and a plurality of axial flow blades spaced about said support disk and extending outward in the general radial direction, axially spaced side plates on opposite sides of each of said support disks each having a generally planar center portion fixed to its associated disk at one side thereof and having an outwardly diverging portion extending from said center portion terminating in inwardly turned rim means at said blades, and means connecting a plurality of said rotors together in spaced relation including tie rods passing through said support disks and said side plates at said planar center portions inwardly of said diverging, side portions securing said rotors into said rotor assembly.

4. An axial flow compressor comprising a rotor assembly having a plurality of rotor stages, each of said rotor stages including a peripheral rim having means defining blade openings therein, a, plurality of blades extending generally radially through said blade openings in said rim, a pair of metal strain relieving fillets for each of said blades received inwardly of said rim and extending through said blade openings radially outwardly beyond said rim, each of said fillets being substantially wider at the portion thereof inwardly of said rim than at the por tion extending radially outwardly of said rim, said fillets having inner surfaces conforming to said blade and an outer surface flared into the blade surface outwardly of said rim and also substantially flaring with the outer surface of said rim, rneanslretaining said fillets on said blade inwardly of said rim, and each of said fillets being freely movable of said blades from said retaining means under centrifugal force into engagement with said rim at said openings to engage said rims and said blades under centrifugal action and relieve bending loads between said rims and said blades where said blades extend through said rim openings.

, References Cited by the Examiner UNITED STATES PATENTS 2,436,087 2/48 Benson 253-39 2,537,739 1/51 Chilton 25339 2,595,829 5/52 Dean .4 253-77 2,772,852 12/56 Stalker 230-134 2,847,184 8/58 Islip 230l34 2,931,621 4/60 ODonnell 230134 2,937,806 5/60 Clarke 253-39 3,045,964 7/62 Stalker 230134 FOREIGN PATENTS 623,710 5/ 49 Great Britain. 738,656 10/55 Great Britain.

JOSEPH H. BRANSON, JR., Primary Examiner.

Claims (1)

1. IN COMBINATION IN AN FLOW COMPRESSOR A COMPRESSOR CASE MEANS, A ROTOR ASSEMBLY MOUNTED IN SAID CASE MEANS FOR ROTATION ABOUT THE ROTOR AXIS, SAID ASSEMBLY COMPRISING A PLURALITY OF ROTORS POSITIONED IN TENDEM, EACH SAID ROTOR COMPRISING A BLADE MEANS INCLUDING A RADIALLY EXTENDING SUPPORT DISK AND A PLURALITY OF AXIAL FLOW BLADES DISENGAGEABLY SECURED THERETO, SAID BLADES BEING PERIPHERALLY SPACED ABOUT SAID SUPPORT DISK AND EXTENDING OUTWARDLY IN THE GENERAL RADIAL DIRECTION, AXIALLY SPACED SIDE PLATES ON OPPOSITE SIDES OF SAID SUPPORT DISK FAYING SAID DISK ALONG AN INNER RADIAL EXTENT THEREOF, SAID PLATES HAVING AN OUTER GENERALLY RADIAL PORTION DIVERGING AXIALLY OUTWARDLY AND TERMINATING AT A RIM MEANS EXTENDING AXIALLY TO OPPOSITE SIDES OF SAID BLADES, AND DISENGAGEABLE CONNECTING MEANS CONNECTING SAID PLURALITY OF ROTORS TOGETHER IN SPACED RELATION INCLUDINGING TIE RODS PASSING SAID SUPPORT DISK AND THE SIDE PLATES RADIALLY INWARDLY OF SAID DIVERGING PORTION OF EACH ROTOR DISENGAGEABLY SECURING SAID ASSEMBLY TOGETHER.

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