US2914297A - Rotor construction - Google Patents

Description

Nov. 24, 1959 G. B WILKES, JR

ROTOR CONSTRUCTION Filed May 3, 1955 7 IN V EN TOR. anew/v 5 /v/L/f, Je.

United States Patent O RoToR CONSTRUCTION Gordon B. Wilkes, Jr., Lynnfield Center, Mass., assignor 'gir `eneral Electric Company, a corporation of New or t y. Application May3, 1955, Serial No. 505,811

3 Claims. (Cl. 253-39.15)

This invention relates to a rotor construction for turbincs, compressors, and blowers or the like. More par- Vticularly, the invention relates to a novel rotor constructage of being expensive. Various constructions have been proposed which will meet stress and cooling requirements and still be within reasonable weight limits, such as hollow or laminated wheels. While these yconstructions have vmerit,- they are still somewhat complicated in their fabrication and, therefore, expensive to make.

Accordingly, it is the primary object of thepresent invention to disclose a'rotor construction of a multi-disk thin wheel type which is lightweight and easily and cheaply fabricated, and lends itself `readily to the use of 'cooling air without the need of a number of air seals.

j Another object is to disclose a rotor construction where- "in the rotor buckets are fastenedcloser to the shaft about which they rotate resulting in a lower operating temperature and a reduction of the bending stresses.

`,The rotor construction shown herein is designed for ei- .ccnt use with the blade construction shown and described 1in,y my co-pending application, Serial No. 497,101 filed yMarch 28, 1955, although its use is not'specically limited to such blade construction.

In carrying out my invention in one form, I provide a rotor construction comprising a plurality of spaced disks adapted to be attached to a preferably hollow rotating shaft, the disks carrying, at their outer peripheries, a series of buckets joined to the disks by a pinned or hinged connection. The buckets are provided with means to prevent the access of hot gases to the space between the disks. In addition, means are provided to permit the cooling of the disks and buckets at all times.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing:

Figure l is a partial axial cross section taken through the rotor showing the rotor connection with the shaft and with the buckets; l

Figure 2 is a perspective view on an enlarged scale showing the hinge and disk connection with the bucket and the false rim associated with the bucket;

Figure 3 is a view similar to Figure 2 and showing a modified form of the false rim, and;

Figure 4 is a perspective view of the false rim structure as used in the embodiment of Figure 2.

t 2,914,297 Patented Nov. V24, 1959 ICC Referring irst to Figure 1, there is shown a rotor genpresent invention. Rotor 10 comprises a plurality of spaced disks consisting of outer disks 11 and inner disks 12. It is to be noted that outer disks 11 are longer in the radial direction than inner disks 12 for a purpose which will hereinafter be described. The phrase longer in the radial direction is intended to include disks 11 that may be the same diameter as inner disks 12 and have radial extensions formed thereon. While two inner disks 12 have been shown, it is obvious that any suitable number may be used. The disks are attached to a shaft 13, which is hollow as at 14, for the passage of cooling air as shown by the arrows. The shaft 13 has a flange 15 for the purpose of attaching the disks to the shaft to permit rotation therewith. The disks are attached to the shaft by suitable means such as bolt 16 which extends through spacer elements 17 and is secured to ange 15. Suitable apertures or openings 18 are provided centrally of the disks, except in the outermost disk 11, to permit passage of cooling air between the disks and radially outwardly thereof as shown by the arrows.

Referring now to Figure 2, there is shown the means for attachment of turbine blades 23 to the disks. The blades 23 are provided with root portions 19, formed of sheet metal construction and bent back upon themselves at inner ends 20, and secured together between ridges or corrugations 21 formed therein. Root portions 19 and ridges 21 extend outwardly to tips 24 of blades 23. Each blade 23 is also provided with an airfoil shaped hollow shell portion 23a, telescoped over the outer end of root portion 19. Shell 23a extends from the inner ends of ridges 21 outwardly to tips 24, defining air passages 22 between the ridges. Each root portion 19 thus includes an inner root portion 19a, extending between folded inner end 20 and the inner ends of ridges 21, as well as an outer portion forming the core of the airfoil portion `23a of the blade. Air passing through passages 22 Vpasses through the blades and over the root portions thereof to exit at the blade tip 24 and provide internal cooling of the blade 23. The method of making its root and the blade structure, per se, is described in my co-pending application referred to above. Eachroot portion 19 is provided with slots 25 in portion 20 thereof equal in number tothe number of disks 12 employed to accommodate inner disks 12 as is clearly seen in Figure'2. Each root portion 20 contains a bushing 26 for the receptionof hinge'pin '27 herein. Each of the disks 11 and 12 is provided with apertures 28 therein for the reception of hinge pins 27.

The outer axial spacing between the disks is preferably the same as that provided by spacer elements 17, so that the disks are parallel to one another. Thus, cylindrical chambers 11a are provided between adjacent disks to permit free and maximum flow of air therebetween from the centers of the disks to their peripheries.

A false rim structure, generally indicated at 29 in Figure 2, is provided between the blades and is spaced radially of root portions 19 from hinge pins 27. The false rim is segmented or made in sections, one form of which is shown in Figures 2 and 4, consisting of overlapping spacer pieces 30 having a blade fitting configuration as shown at 30a. The spacer pieces 30 are suitably secured to blades 23, as by welding to form an integral construction therewith.

As seen in Figure 2, two matching spacer pieces 30 are used between each pair of blades to provide the proper spacing and support therebetween and to prohibit radially outward flow of uid passing over the outer surfaces of blades 23. Outer disks 11 are etxended radially as shown,

or by extensions attached thereto outwardly to the false rim 29, to provide iluid confining chambers from the shaft 13 outwardly to the air passages 22. The cooling uid then passes between all of the disks and is forced through the passages 22 to the blade tips 24 to provide cooling of the whole rotor structure including the blades.

Referring now to ,Figure 3, there is shown a modification of the false rim structure. In this modification, the false rim consists of a plurality of single sheet metal pieces 31 located between each pair of blades to providethe proper spacing between the blades. Each piece 31 is suitably secured to an adjacent blade, and has suitable apertures 32 therein to direct the cooling fluid into passages 22 and thence radially outwardly, between the blade 23 and root portion 19 to the blade tips 24. Except as to the false rirn structure, the rest of the blade construction and its cooperation with the wheel disks is the same as that shown in Figure 2, and like numerals have'been applied to like parts.

It is important that the false rim structure be located substantially radially outward of the hinge connection with the disks. This puts the hinge connection well away from the heat of the combustion gases if the rotor is used in high temperature application for which it is generally preferable, although the rotor is not necessarily limited to such applications. In other words, the false rim contines the hot gases to the preferred area. The extension of the outer disks 11 to the false rim provides a confining means for the cooling uid. It will be appreciated that the number of disks required is dictated by strength requirements at the rim of the disks and the shear area necessary in the hinge pin. The particular construction herein described eliminates all seals between stationary and rotating parts as far as the cooling air system is concerned.

While I have described my invention in detail in its present preferred embodiments, it will be obvious to those skilled in the art, that various changes and modifications may be made therein withoutdeparting from the spirit or scope thereof.

I claim:

1. A rotor for turbines, compressors, and the like, comprising a hollow rotor shaft, a plurality of spaced disks mounted coaxially upon and end of said shaft, said disks defining a plurality of cylindrical chambers therebetween, the outer two of said disks being radially longer than the inner ones of said disks, each of said disks except the one of said outer disks spaced farthest from said end of said hollow shaft being formed with an aperture to connect each of said chambers in cooling fluid low communication with said hollow shaft, a row of circumferentially spaced blades attached to said disks radially inwardly of the periphery of said outer disks and extending radially outwardly from said outer disks, said blades formed with air passages extending radially outwardly therethrough, said air passages being in cooling uid flow communica tion with said chambers, and a false rim structure on said blades extending between said blades and said outer disks to enclose said chambers from uid flow communication with the exteriorof Vsaidrotor through the spaces defined by adjacent ones .of said blades and said outer disks.

2. A rotor for turbines, compressors, an'd the.like,.corn prising a hollow rotorshaft, a,pluralitylof-spacedidisks mounted coaxially upon an end of said shaft, aspacer means between said disks,said disks defining a .plurality of cylindrical chambers therebetween, the outer two of said disks being radially longer than Athe inner ones of said disks, each of said disks except the one of said outer disks spaced farthest from said end of said hollow shaft being formed with an aperture to connect each of said chambers in cooling uidow communication with said hollow shaft, a row of circumferentially spaced blades formed with root portions, said root portions attached to said disks radially inwardly of theperiphery of "said outer disks and extending radially outwardly from said outer disks, each of said blades provided with a hollow arfoil shell portion telescoped over theouter `end'o'f said root portion thereof to form airpassages extending radially therethrough, said air passages Vbeing in cooling'uid tiow communication with said chambers, and a false rim structure on said blades extending between 'saidblades yand said outer disks to enclose said chambers from 'iiuid flow communication with the exterior of said rotor 'through Vthe spaces defined by adjacent ones of said'blades and said outer disks.

3. A rotor as recited in claim 2, .in which said blades are formed with slots at the inner endslthereof vreceiving said inner disks, together with a `plurality vof pins each securing the inner end of one of said vbladesto said disks.

References Cited in thertile of this patent UNITED STATES PATENTS 2,537,739 Chilton Jan. 9,1951 2,613,058 Atkinson Oct. 7, 1952 2,649,278 Stalker Allg. 18, `1953 2,657,008 Atkinson Oct. `27., 1953 FOREIGN PATENTS l 667,979 Great Britain Mar. 12,1952 687,507 Great Britain Feb. 18,1953 989,556 France ..-i May 23, `19,51

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