US3081021A

US3081021A - Fabricated wheel and blade attachments

Info

Publication number: US3081021A
Application number: US846505A
Authority: US
Inventors: William S Castle; John B Minnich
Original assignee: General Motors Corp
Current assignee: Motors Liquidation Co
Priority date: 1959-10-14
Filing date: 1959-10-14
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12

Description

March 1963 w. s. CASTLE ETAL 3,081,021

FABRICATED WHEEL AND BLADE ATTACHMENTS Filed 0012. 14, 1959 5 Sheets-Sheet 1 INVENTORS' ZZZ A fizz/m 542M: 5. 00 B e/air z? z/$ MZW-w ATTORNEY March 12, 1963 w. s. CASTLE ETAL 3,081,021

FABRICATED WHEEL AND BLADE ATTACHMENTS Filed Oct. 14, 1959 5 Sheets-Sheet 2 ATTORNEY W. S. CASTLE ETAL March 12, 1963 FABRICATED WHEEL AND BLADE ATTACHMENTS 3 Sheets-Sheet 3 Filed Oct. 14, 1959 United States PatentOfiFice 3,081,021 Patented Mar. 12, 1963 3,081,021 FABRICATED WHEEL AND BLADE ATTACHMENTS William S. Castle, Speedway, and John B. Minnicli, Indianapolis, Ind., assignors to General Motors Corporation, Detroit, Micl1., a corporation of Delaware Filed Oct. 14, 1959, Ser. No. 846,505 2 Claims. (Cl. 230-134) This invention relates to a rotor assembly.

More particularly, it is an object of-this invention to provide a low cost fabricated rotor assembly that is easy to assemble and disassemble.

1 Other objects, features ad advantages will become apparent upon reference to the succeeding detailed description and to the drawings illustrating the preferred embodiments of the invention, wherein:

FIGURE 1 is a front elevational view with parts broken away and in section of one embodiment of the invention,

FIGURE 2 is an enlarged plan view with parts broken away and in section taken on a plane indicated by and viewed in the direction of the arrows 22 of FIG- URE 1,

FIGURE 3 is a cross-sectional view taken on a plane indicated by and viewed in the direction of arrows 3--3 of FIGURE 1,

FIGURE 4 is a cross-sectional view taken on a plane indicated by and viewed in the direction of the arrows 4-4 of FIGURE 1,

FIGURE 5 is an enlarged exploded perspective view of a detail,

FIGURE 6 is a front elevational view of another embodiment of the invention,

FIGURE 7 is a cross-sectional view taken on a plane indicated by and viewed in the direction of arrows 77 of FIGURE 6, and

FIGURE 8 is a cross-sectional view taken on a plane indicated and viewed in the direction of arrows 8-8 of FIGURE 6.

Referring to the drawings and more particularly to FIGURE 1, there is shown therein an arcuate portion of an axial flow type rotor assembly 12 incorporating one embodiment of this invention, the assembly including a number of blades 14 adapted to be secured to a rotor 16 and spaced equally circumferentially therearound by a number of spacers 18.

Referring more particularly to the details, each of the blades 14 is preferably machined from bar stock in the shape of an airfoil as shown so as to provide an enlarged inclined root or base portion 20 integral therewith at the radially inner end 22 thereof.

As seen more clearly in FIGURES 2 and 5, each of the root portions 20 is undercut or recessed at opposite sides 24 and 26 by suitable milling operations to provide radially, axially and circumferentially spaced tang portions 28 and 30 depending from the blade. The milling operations and spacing also provide on opposite sides of the root of shelf portion 32 (FIGURE 1), 34 at one edge formed integral with the upper edge of the tang portion 28 or 39 to together constitute a blade platform 36 inclined with respect to the axis so as to direct the how of air thereover in the most advantageous and efiicient direction. a

The radial spacing of the tang portions provides a line of connection and support of the blades to the rotor at the same inclination as the blade platform and the air flowing thereover thus providing a more durable connection. The tang portions are also circumferentially spaced from each other so as to be positioned directly below the adjacent curved portion of the airfoil, which is supported thereby, to give the best distribution of stress.

The tang portions are further axially spaced with respect to each other for cooperation with two axially spaced parallel annular sheet metal plates 38 and 40 secured together at 42 by suitable means to comprise the rot-or wheel 16, each of the tang portions being circumferentially cut at its inner end to provide a radial slot 42, 44 for receiving the discs 38 and 40 therein. The tang portions are adapted to be secured to the discs by the insertion of rivets 46, 48 in the

holes

50, 52 and 54, 56, respectively. It will be seen therefore that the overall configuration of each blade root matches the curvature of the blade from which the root depends therefore providing for a minimum of metal while giving optimum stress distribution and support to the blade. v

Each of the blades or airfoil assemblies is adapted to be circumferentially spaced from each other by spacer means 18 comprising two axially spaced radial sheet metal plates 60 and 62 axially flanged at 6'4 and 66 for cooperation with a top sheet metal plate 68 constituting a platform inclined at the same angle as the blade platform 36 for cooperation therewith. The plates 60 and 62, as well as platform 68, extend circumferentially for the entire desired spacing between blades so as to not only constitute a continuous streamlined surface to reduce friction, etc., losses, but also an air or gas seal to reduce to a minimum the passage of air or gas between the blades in any direction or path other than over the platforms 36 and 68. The leg plates 60 and 62 are radially spaced for the same purpose as are tang portions 28, 30, and are axially spaced so as to fit Within the opening defined by the axial distance between rotor discs 38 and 40 to which they are adapted to be rive-ted as shown.

The assembly of this embodiment of the invention is believed to be clear from the drawings; however, a brief resume will be given. The tang portions 28 and 30 of the airfoils are dropped into place over the rotor discs 38 and 40 so as to straddle the same with the holes 50, 52 and 54,- 56 therein being aligned, and the rivets 44, 46 are inserted therein. The spacer means 58 which has been preassembled by riveting the leg plates 60 and 62 to the platform 68 at 69 and 70, is then dropped in place between the discs 38 and 40 with the holes 71 and 72 therein aligned with the holes 74 and 76 in the discs, and the edge of the platform 68 abutting the adjacent edge of the platform 36, and the rivets 78 are then inserted therein. The next circumferentially adjacent blade and root is then riveted to the rotor wheel, with the connection of the spacer means following, etc., until the entire rotor is assembled. Thus, a low weight, high strength, economically fabricated rotor assembly is provided. The assembly may be disassembled by a shearing oif of the rivet heads and a reversal of the assembly procedure.

FIGURES 6 to 8 illustrate another embodiment of the inven ion, this embodiment differing from the FIGURES l to 5 embodiment primarily in the construction of the blade root to accommodate connection thereof to two non-parallel axially spaced sheet metal annular plates or discs 80 and 82 comprising the rotor wheel.

In this embodiment, the converging discs 80 and 82 are each provided at their peripheries with radially extend-.

ing axially spaced portions 84 and 86 parallel to each other and adapted to be received within two axially spaced radial slots 88 and 90 circumferentially cut in the depending tank 92 of the root or base 94 of a blade 96. The blade or airfoil 96 is constructed in a manner similar to that of FIGURES 1 to 5 embodiment, i.e., machined from bar stock in the shape of an airfoil while providing an enlarged root portion. The root portion is milled or recessed both at the upstream and the downstream sides of the assembly to provide circumferentially spaced struts 98 and 100, respectively, for distributing the spar-p21 stress from the blades to the connection to the discs. The I trimming away of the metal between strutsreducing'the weight of the root to a low value. The milling thus provides a root having a centrally depending slotted radial tank portion 92 with substantially axially extending shelf portions 102 and 104 together constituting a blade platform 1% inclined as shown in the same direction and for the same purpose as the FIGURES 1 to embodiment.

The spacer means 108 is substantially the same as that of FIGURE 4, comprising two sheet metal

radial plates

110 and 112 axially spaced by a spacer 113, flanged at 114 and 116 and riveted to an inclined platform 113 at 129 and 122, the axial spacing of the plates being such as to permit straddling of the two discs 80 and 82 by the plates, and riveting them together.

The assembly of this embodiment is substantially the same as the FIGURES 1-5 embodiments, i.e., the blade and tang 92 are dropped into place over the discs 80' and 82 and riveted thereto by the insertion of the rivets 124 into the holes provided in the tank and discs. The preassembled spacer means 108 is then placed over the two discs as shown in FIGURE 8, and riveted thereto by rivets 126 being inserted in the holes provided in the discs, a spacer member 113 being positioned therebetween. The next circumferentially adjacent blade assembly is then inserted in place and riveted, followed by a spacer means, and so on around the circumference of the rotor wheel until the entire rotor is assembled. The assembly may be also easily disassembled by shearing off the rivets, and reversing the assembly operation.

Thus, a rotor assembly of very light weight and great strength is provided for easy and economical fabrication.

While the preferred embodiments of the invention have been illustrated in FIGURES 1 to 8, it will be clear that many modifications can be made thereto by those skilled in the art to which this invention pertains without departing from the scope of the invention.

We claim:

1. A lightweight rotor blade assembly comprising a rotor, a plurality of thin arcuately curved airfoil type blades adapted to be secured to said rotor at the periphery thereof, spacer means for circumferentially spacing said blades and spanning the gap therebetween, and means for securing said blades and spacer means and said rotor rigidly together, said rotor comprising a number of annular axially spaced plates, each of said blades having an enlarged root integral with and beneath said blade and having an overall configuration substantially matching the curvature of said blade, each of said roots having axially and circumferentially spaced tang portions depending radially beneath and being substantially aligned with the leading and trailing edges of said blade, each of said tang portions being slotted to receive a rotor plate therein, said root having other portions extending between and connecting said tang portions to support all portions of said blade.

2. A rotor blade assembly as in claim 1, wherein said other portions extend from each of said tang portions each in a different direction, said other portions being recessed, said recesses being axially and circumferentially spaced from each other and each forming a shelf portion-integral with each other and said tang portions, said tang portions and shelf portions together constituting a platform for said blade, said tang portions depending beneath diametrically opposite edge portions of said platform.

References Cited in the file of this patent FOREIGN PATENTS 528,031 France Oct. 6, 1921 652,099 Great Britain Apr. 18, 1951 718,139 Great Britain Nov. 10, 724,281 Great Britain Feb. 16, 1955 742,194 Great Britain Dec. 21, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,081,021 March 12, 1963 William 5. Castle et al.

- It 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 l line 14, for "ad" read and for "of" read a tang line 59, column 3, line 21, for "tank" read Signed and sealed this 8th day of October 1963.,

(SEAL) Attest:

' EDWI I ERNEST w. SWIDER REYNOLDS- Attesting Officer Ac t i ng Commissioner of Patents