US2880962A

US2880962A - Axial flow bladed rotor construction

Info

Publication number: US2880962A
Application number: US213598A
Authority: US
Inventors: Edward A Stalker
Original assignee: Stalker Development Co
Current assignee: Stalker Development Co
Priority date: 1951-03-02
Filing date: 1951-03-02
Publication date: 1959-04-07
Anticipated expiration: 1976-04-07

Description

E. A. STAYLKER AXIAL FLOW BLADED ROTOR CONSTRUCTION 3 Sheets-Sheet 1 April 7, 1959 Filed March 2, 1951 w I v I 22 IN V EN TOR.

April 7, 1959 E. A. STALKER 2,880,962"

AXIAL FLOW BLADED- ROTOR CONSTRUCTION Filed March 2, 1951, 3 Sheets-Sheet" 2 IN VEN TOR.

April 7, 1959 E. A. STALKER 'AXIA'L FLOW BLADED ROTOR iJONSTRUCTION Filed March 2, 1951 3 Sheets-Sheet 3 IN VEN TOR.

United States Patent AXIAL FLOW BLADED ROTOR CONSTRUCTION Edward A. Stalker, Bay City, Mich., assignor to The Stalker Development Company, Bay City, Mich., a corporation of Michigan Application March 2, 1951, Serial No. 213,598

12 Claims. (Cl. 253-39) This invention relates to the construction of axial flow bladed rotors adapted to interchange energy with a fluid.

An object of the invention is to provide a bladed rotor construction wherein the important structural parts may be resistance-welded together to hold them in proper relation while they are being brazed together.

Another object is to provide a rotor structure which may be entirely welded together by machine welding, such as resistance welding.

Other objects will appear from the description, drawings and claims.

The above objects are accomplished by the means illustrated in the accompanying drawings in which- Fig. 1 is an axial view of a bladed axial flow rotor;

Fig. 2 is a fragmentary section through the rotor along line 22 in Fig. i;

Fig. 3 is a fragmentary perspective of a blade and its stem;

Fig. 3a is a sectional view through one of the hollow blades on the line 3a3a of Fig. 1;

Fig. 4 is a fragment of a section of the hub structure as seen from line 4-4 in Fig. 2;

Fig. 5 is a fragment of the hub rim in radial view showing the blade cutouts;

Fig. 6 is a fragmentary axial section showing the welding electrodes in position;

Fig. 7 is a fragmentary view of an electrode;

Fig. 8 is a fragmentary axial section of the rotor hub;

Fig. 9 is a fragment section along 9--9 in Fig. 8; and

Fig. 10 is a fragmentary axial section of the rotor with the torque sleeve in place. 1

Referring now to the drawings the rotor is indicated generally as 10. It comprises the hub structure 12 and the blades 14 which define rotor flow passages extending in a general axial direction between successive blades as shown at 15 in Fig. 5 for discharging fluid rearwardly in the general axial direction.

The hub structure comprises the

plates

20 and 22 spaced apart by the stems 24 which extend radially and are spaced peripherally about the plates. Each stem is integral with the blade at its outer end. The blade is formed by folding the tab 26 to join the upper surface 27 at the trailing edge 28 as shown in Fig. 3. The surfaces are spot welded at several points along the trailing edge to establish the blade twist without the use of a jig while it is being brazed or soldered subsequently.

The rim 32 of the hub structure comprises the two hub

rim closure elements

34 and 36 having inturned axially extending

flange portions

40 and 42 located at the base of the blades, such flange portions being [fused together at the joint 38 and spot welded and brazed to the

plates

20 and 22 at the outer peripheries thereof. 7

The rim has the cut-outs 39 for the blades (Fig. 5), and

hence substantially close the rotor between the blades and between

plates

20 and 22 at the outer peripheries thereof from the inlets to the exits of flow passages 15.

As shown in Figs. 2 and 4 the

plates

20 and 22 abut against the

flange portions

40 and 42 of th'e'hub "ice closure elements-to support and position them. The

plates

20 and 22 have the radial

extensive slots

21 and 23 respectively.

The rotor has the central opening 50 framed by the

clutch elements

52 and 53 such opening in one of the plates such as 20 being greater in diameter than one-third of the hub diameter. Each clutch element has teeth 54 for engaging one rotor with another.

The method of assembling the rotor is to spot or resistance weld one of the radially extending

flanges

60 or 62 at either side of the webs of the stems to one of the plates, in this instance 60 to 20 for purposes of illustration. The rim closure element 34 is also welded to the plate. Since both sides of the plate are accessible these parts are readily resistance welded on welding machines.

The plate 22 and its rim closure element 36 are likewise welded together.

The two assemblies are placed opposite each other so that plate 22 bears on the flange 62 of each stem 24. The

flanges

40 and 42 fit snugly about the root ends of the blades 14. This excludes the possibility of welding the flanges of the webs of stems to plate 22 with direct normal approach of the electrodes to the surfaces.

Through the central opening 50 an electrode 70 (Figs. 6 and 7) is insertable so that in cooperation with the exterior electrodes 7174 the flange 62 can be tacked by spot welds to the plate 22 at limited areas along the radial extent of the overlapping parts thereof.

The purpose of the spot welds or other welds of limited area is to position the parts and hold them in close relationship so that brazing material will flow by capillary action into the joints and fuse them together when the structure is heated to secure the stems to the side plates 'over a major portion of the radially extending overeach be welded to its respective plate before assembly into the rotor or afterward as shown in Fig. 6. For .this purpose the electrode 75 is placed opposite the point 76 of electrode 70.

Where rotors are used or driven singly, any axial pressure between the rings 52 can be taken by the webs of stems 24, particularly if they have a flange 80, Figs. 8 and 9, to stiffen the lower edge of the web.

Where the rotors are stacked along the axis, some rotors will have to transmit the driving torque to several rotors through the clutch elements on the opposite sides of the rotor. This means that a very large torque must be transmitted from the front to the rear clutch element of the rotor, as from 52 to 53. For this purpose the sleeve 82 is fixed or fused to the

clutch blanks

52 and 53 as shown in Fig. 10. This member is fixed in place after the welding of the plate 22 and the flanges 62.

The portions of the

plates

20 and 22 near the rim do not carry blade loads but serve chiefly to position the

flanges

40 and 42 so lightening holes 86 may be placed in the plates.

If the rotor structure is tacked together by fused metal of relatively high melting point, the brazing or soldering of the joints may be accomplished with a sufficiently low melting point material that only elementary fixtures need be used.

Silver solder can then-be used at the jointstoboud theiparts together in a'furnace with a suitable atmosphere such as hydrogen.

If very thin sheet metal is employed the parts can be tacked together at spots with copper to avoid excessive melting or dimpling of the surfaces by the electrodes. The steel surfaces are coated w'ithcopper atthe localities to be tacked together. The tacking is done with electrodes as in spot welding.

"Since silver solder melts at only about 1300" F. as compared to 2100 for copper, the copper spots will hold the parts in proper relation while the silver soldering process is conducted. Also since the silver solder melts at low temperature only the simplest fixture is required to support the rotor. In many cases only a flat support plate is required.

It'will now be clear that i have disclosed a rotor struc- 'ture formed from metals'tampin'gs or-pressings in which walled in parts are accessible for bonding together at strategically disposed localties.

It will also be clear that I have provided a structurally sound sheet metal bladed structure which is very light in weight and economical to produce. In fact the rotor structure will weigh as little as 40 percent of rotors of contemporary practice and cost about 25 percent'of their cost.

While Ihave illustrated a specific form of this invention his to beunderstood that I do not intend to'limit myself to this exact form but intend to claim my invention broadly as indicatedby the appended claims.

I claim:

1. In an axial 'tlowrotor having blades defining rotor fl'owpassages between adjacent blades extending in the general axial direction for discharging fluid rearward in the general axial direction, a hub structure including a first .plate assembly comprising a generally circular plate and a'plurality of spaced radially directed blade stems joined to said plate in peripherally spaced relation there- "about, each said stem extending radially outwardly beyond said plate assembly to support a separate one of said blades, a second plate assembly including asecond generally circular plate fitting against said stems opposite the first said plate, said assemblies including hub rim closure means secured 'to'said respective plates and substantially closing the rotor between said blades and between said plates adjacent the outer perimeters thereof, said second plate being joined to said stems at limited areas along the radial extent of the overlapping parts thereof, one of said plates being provided with a central opening large enough for the insertion of a welding electrode against saidstems along the radial extent thereof, and brazing material joining said plates to said stems over -.a major portion of the radially extending overlapping .plates and substantially closing the rotor between said blades and between .said plates adjacent the perimeters thereof, said second plate having welds joiningsaid second plate to said stems over a major portion of theradially extending overlapping areas thereof radially inwardly of said rim closure means, one of said plates being provided with a'central opening large enough for the insertion of a welding electrode against said stems at the locations of .saidwelds, said stems extendingzontwardly ,heyondsaid trim 'closuremeans and said plates and supporting the :several blades.

3. In an axial flow rotor ihaving blades definingzrotor passages extending in the general axial direction for disichargingfiuid rearward -in the,general,axial direction, a

hub structure including a plate assembly comprising a first plate "and a plurality of radially directed stems fixed to said plate in peripherally spaced relation thereabout and extending outwardly to support the several blades, a second plate fitting against said stems opposite the first said plate, rim closure means secured to said respective plates and substantially closing the rotor passages between said blades and between said plates adjacent the perimeters thereof, said stems extending radially inwardly in overlapping relation with both said plates over a major extent thereof radially inwardly of said rim closure means and being welded to said plates, one of v-said plates being provided with a central opening large enough for the insertion of a-welding electrode against said-stems at the locations of said welds, and annular clutch elements fixed to a said plate encircling said opening in said plate.

4. In an axial flow rotor having blades defining rotor passages extending in the general axial direction for dischargingifluid rearward 'in the general axialdirection, a

-hub structure including a first plate assembly'having a plate and a pluralityof radially directed stems fixed to said plate over a major portion of the radial extent'thereof'in peripherally spacedrelation thereabout and extending outwardly ,to support the several blades, a second plate assembly having a second plate fitting against said stems opposite the first said plate, said assemblies including hub rim closure means substantially closing the rotor between said blades and between said plates :adjacent the outer perimeters thereof, said stems having welds joining the same to'both said plates over a major portion the stems have web portions and marginal flanges 'extending along their respective sides in overlapping relation with said plates.

7. In an axial flow rotor having blades defining rotor passages extending in the general axial direction for discharging fluid rearward in the general axial direction, :a

'hub structure including a first ,plate assembly having a plate and a plurality of radially directed stems fixed :to said plate in peripherally spaced relation thereabout and extending outwardly to support theseveral blades, a second plate assemblyhaving a'second plate fitting against said stems opposite the first said plate, said plate assemblies including rim closure means at the base of said blades substantially closing the rotor between said blades andbet-ween said plates adjacent the outer perimeters :thereo'f, said stems extending radially inwardly in overlappingrelation-with' both-said plates over a majorportion of the distance inwardly from said rim closure meansan'd being welded to said plates, one ofsaid plates being provided with a central opening large enough for the insertion of a welding-electrode against said stems at the locations -of-said-welds, sa-id opening in said plate being greater indiameter than one-third of said hub diameter.

8. An'axial'fiow rotor as defined in claim 7 in which thehub rim closure means of the respective plate assemblies'arefused together at'their meeting edges.

9. An axial "flow rotor as defined in claim 7 in which the hub rim closure means at the base of the blades fits against the 'outer peripheries of said first and second plates respectively for supporting said closure means against radially inward pressure.

10. The process of producing an axial flow bladefd rotor which has 'asubstantially closed hub surface 1between thelblades at the roots thereof comprising the steps of-welding onerside of a "plurality of radially directed stem'elements' toafirstplate' in peripherally spaced areas,

placing a second ,plate against theside of said plurality of stem elements axially opposite the first said plate, ,placingzanelectrodeagainst a said stem element through an opening in a said plate, placing an electrode against said second plate, directing electric current from one electrode to the other through a said stem element and said second plate to form welds joining said stem elements to said second plate, providing brazing material at the joints between said plates and stem elements, heating said rotor to cause said brazing material to flow into the joints between said plates and said stem elements, and forming blade envelopes in operative position upon each of said radially directed stem elements.

11. The process of producing an axial flow bladed rotor which has a substantially closed hub surface between the blades at the roots thereof comprising the steps of welding a plurality of radially directed stem elements having radially extending flanges to a first plate in peripherally spaced relation, placing a second plate having similar flanges against the opposite flanges of said elements axially opposite the first said plate, placing an electrode against a said stem element through an opening in said plate, placing an electrode against said second plate, directing electric current from one electrode to the other through a said stem element and said second plate to form welds joining said stem element to said second plate, providing brazing material at the joints between said plates and stem elements, heating said rotor to cause said brazing material to flow into the joints between said plates and said stem elements, and forming blade envelopes in operative position upon each of said radially directed stem elements.

12. In an axial flow rotor for exchanging energy with a fluid, a hub structure including a front plate and a rear plate spaced apart axially, a hub rim closure means having a generally radially extending part fixed to each said plate adjacent the perimeter thereof, said closure means having a rim flange radially outwardly of said plates extending in the peripheral direction in rim closing relationship, a plurality of axial flow blades peripherally spaced about said rim flanges extending inward therethrough and carried on said hub structure, at least one of said plates extending to and terminating substantially at the radially inward surface of said rim flange for support thereof.

References Cited in the file of this patent UNITED STATES PATENTS 874,398 De Ferranti Dec. 24, 1907 1,417,029 Carlson May 23, 1922 1,641,745 Dimberg Sept. 6, 1927 1,919,970 Woods July 25, 1933 2,117,688 Stone May 17, 1938 2,432,185 Watson Dec. 9, 1947 2,458,149 Cronstedt Jan. 4, 1949 2,461,242 Soderberg Feb. 8, 1949 2,497,151 Clark Feb. 14, 1950 2,559,013 Eastman et al. July 3, 1951 2,604,298 Bachle July 2, 1952 FOREIGN PATENTS 20,818 Great Britain of 1906