US2954208A

US2954208A - Air foil section

Info

Publication number: US2954208A
Application number: US330464A
Authority: US
Inventors: Robert W Ewald; Charles A Nichols
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1953-01-09
Filing date: 1953-01-09
Publication date: 1960-09-27
Anticipated expiration: 1977-09-27

Description

,sept.27, 1960 Rw. LD Em., 2,954,208

' AIR SECTION Filed Jan. 9, 1953 Mlm IN VEN TOR A j* 4% 4 M x ATM/MVS nited States Patent AIR FOIL SECTION Filed Jan.9, 1953, Ser. No. 330,464

3 Claims. (Cl. 253-77) This invention'relates toair foils and more particularly to a hollow air foil section Vandmeth'od of making the same. f

An object of this invention4 is to form a hollow air foil section such as a compressor blade from sheet material having a mountingmeans integrally formed therewith.

Another object of this invention is' to form a hollow internally reinforced compressorblade from sheet material wherein the mounting or foot portion integrally formed with the blade is adapted torfixedly attachthe blade to a support. l W

A more specific object of this invention is to provide a method for forming a hollow light weight compressor blade of relatively large size from sheet material by folding the sheet, brazing edges of the sheet together, and internally reinforcing the blade portion thus formed. A mounting means for the blade portion is integrally formed therewith and has at least a portion thereof wrapped about a solid ller which forms a part of the foot whereby the blade portion is rigidly supported.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

ln the drawings:

Fig. 1 shows a side View of air foil section embodying the present invention.

Fig. 2 is an end View of Fig. 1.

Fig. 3 is a section along line 3-3 in Fig. 1.

Fig. 4 is a section 4along line 4-4 in Fig. 1.

Fig. 5 is a section along line 5 5 in Fig. 1.

Fig. 6 is an enlargement of encircled portion 6 in Fig. 3.

Fig. 7 is an enlargement of the encircled portion 7 of Fig. 3.

Fig. 8 is one modification of Fig. 4.

Fig. 9 is another modification of Fig.`4.

Blades or airfoil sections for turbines, compressors and the like are used in many sizes and lengths according to the speciiic stage within the machine. In certain stages the blades are relatively small and are made by various methods from conventional materials in solid form. As the size of the blade increases the weight of the material thereon has a definite bearing on the use and etliciency of the unit.

For this reason it is often desirable to reduce the weight of blades over ve to six inches in length for example. In order to accomplish this end, sheet metal fabricated blades have many useful features. However these blades have lacked strength, particularly at the joining portions between the airfoil section and the foot, which condition has prevented their widespread use.

This invention attacks the problem in a different manner than prior art advances and removes the retarding portions toward the use of sheet metal blade. This is accomplished by providing a strong and unitary foot 2 Y structure integral with the airfoil section which can be readily made in large scale production.

ln the drawings reference numeral 20 designates an air foil member particularly adapted for use in axial llow compressors wherein blades relatively light in weight and large in size are often required. This air foil member 20, has a blade or air foil section 22 and a foot or root portion 24 integrally formed therewith. This member is formed fromk a single sheet of material which is cut into a predetermined shape. lAfterthe sheet is cut,V it is folded so that two opposed edges are in abutting relation whereby they may be joined by `brazing (Fig. 6) `or any other suitable method to form a blade 22 having integrally attached thereto the foot 24.

The foot 24 includes foot mounting portion 36` (Fig. 4) that has extending

arms

38 and 40 integral with the blade wrapped around a solid ller or support 42 and may be more rrnly attachedV to support` 42 by` some suitable method such as brazing. YThe blade is further provided with clamping strips which form clip-like members 43 (Fig. l) that `are wrapped about and brazed to the ends of ller 42. The strips 43 are used to prevent any slip between the blade and the liller and are also used to make the outer dimension of the foot 24 conform throughout its full extent. As shown in Fig. l, clip-like i members 43 extend beyond the leadingand trailing edges of the airfoil member 20.

The foot 24 of the finished blade may be then inserted in a cooperating slot in a mounting ring or member of the compressor thereby securely attaching the blade 22 to the mounting through the foot 24. The cooperating slot in the mounting 37 is dimensioned to snugly accommodate the foot 24, and has angular portionsv 41 arranged for forming a narrowed necked portion 39 therebetween in the mounting 37. This necked portion 39 formed of angular portions 41 provides an interlocking retaining means and serves to maintain the blade in position against circumferential movement relative to the slot.' Thus it will be apparent that when the blade is mounted, the airfoil section and its foot mounting will be rrnly clamped to provide a secure attachment for the air foil section. This type of construction, wherein the attaching means is integrally formed with the air foil section, provides a continuous surface in a one-piece structure without joints and thereby eliminates weakened portions normally present at the junction of the blade and root wherein joining techniques such as brazing or welding have been used.

An internal reinforcing member 25 which is included within the air foil section 22 (Fig. 3) comprises a V- shaped element (Figs. 3 and 7) having an apex 29 joined to one internal surface 32 and the connected extending arm portions 28 and 30 joined to the other internal surface 34 of the air foil section.

The blade as herein disclosed may be used with or without integral reinforcing means depending upon the thickness of the sheet `and the overall dimensions. If reinforcing means are employed, the blade structure should be of suicient strength to support the strut or brace which may be suitably attached to the internal surface of the blade as shown in Fig. 3.

A modification, as seen in Fig. 9, shows a structure providing additional reinforcing means for the air foil section. This is achieved by having a portion Si) of the liller 42 extend into the `air foil section 22 to provide additional reinforcing means adjacent the root, where blade failures generally occur.

Another means of reinforcing the blade is through the use of plastic fillers. Any suitable material such as: rubber-like materials, thermosetting or thermoplastic resins etc. in fact any material which will withstand the ambient temperature condition may be used. A plastic a 2,954,298v lee Patented sept. 27, raso.

reinforcing means 46 as shown in Fig. 8, may be used and will provide additional rigidity and impart strength to the blade. It is understood that similar llers may be used in connection with any Vof the blade structure shown.

It is `apparent that Ythis invention is partieularly directed to an improved blade and to a method of attaching the blade in an element of an axial llow compressor. The attachment in the present instance is accomplished by having the lroot portions of the air foil member integrally formed with the air foil section. The extending root portions which are wrapped about a solid ller may be brazed thereto to form a composite reinforced foot. When said foot is inserted into a suitably shaped recess in a supporting ring or rim, a unitary connection -will -result between the lblade portion of the air foil member and the support.

While the embodiment of the present invention, as herein disclosed, constitutes a preferred f orm, it is to be understood that other forms might Ybe adopted.

What is claimed is as follows:

1. An airfoil member comprising: a hollow air'foil portion having a predetermined cross-sectional shape, and a foot portion integrally formed with said airfoil pon tion for supporting said `airfoil portion lin a mounting support, a solid ller member for'said foot portion having a non-curvilinear cross-sectional shape, said foot portion including a pair of arm portions Wrapped around the sides of and embracing a central section of said filler member, and a pair of clip members wrapped around 4 `and brazed to the ends of said filler member and extending Abeyond the 4leading andtrailing edges of said airfoil portion, said clip members preventing slippage between said foot portion and said filler member and providing a uniform outer surface on said ller member.

2. A hollow airfoil member as set forth in claim l wherein the airfoil portion has `reinforcing means therein.

3. The hollow airfoil member as set forth in claim 1 wherein a portion vonly of the filler member extends into a portion of `the airfoil 'section for providing `support for the airfoil section.

References Cited in the file kof this patent UNITED STATES PATENTS 994,166 Kienast .Tune 6, 1911 2,431,660 Gaudenzi Nov. 25, 1947 2,512,264 Brauchler June 20, 1950 2,520,373 Price Aug. 29, y1950 2,537,739 Chilton Jan. 9, 1951 2,559,131 Oestrich July 3, 1951 2,577,336 Lampton Dec. 4, 1,951 2,642,263 Thorp June 16, 1953 2,656,146 ,Sollinger Oct. 20, 1953 2,823,894 Gerdan Feb. 18, 1958 FOREIGN PATENTS 42,539 Austria `lune 10, 1910 131,574 Australia Mar. 1, 1949 628,036 .Great Britain Aug. 22, 19.49 1,007,303 France Feb. 6, 1952