US2956189A - Electrical machine rotor - Google Patents

Description

Oct. 11, 1960 E. J. Buss ETAL ELECTRICAL MACHINE Ro'roR Filed Oct. 23, 1957 United States Patent @ffice 2,956,189 Patented Oct. 11, 1960 ELEC'I'RICAL MACHINE ROTOR Edward J. Buss, Guy Russell Fansher, John H. Groves, and George E. ODonald, all of Freeport, Ill., assignors to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois Filed Oct. 23, 1957, Ser. No. 691,939

5 Claims. (Cl. 310-211) This invention relates to improvements in rotors for electrical machines, and more particularly to an improved rotor construction for an electrical machine of the socalled axial air gap type.

An object of the present invention is to provide a unitary rotor comprised of a rotor frame, a magnetic core and a cast squirrel-cage type winding, wherein the rotor is characterized by an improved construction affording rigid assembly connection of the parts by the cast winding.

Another object is to provide a unitary rotor of the character indicated, wherein the rotor frame embodies means locating the core on the frame and serving in Acooperation with the cast Winding, to effect securement of the core and frame in rigid assembly.

A further object is to aiford a rotor construction of the aforesaid character, which facilitates production of the cast winding by centrifugal casting to the frame and core.

Other objects and advantages attained will appear from the following description of a presently preferred embodiment of the invention, as such is illustrated by the accompanying drawing, wherein:

Fig. 1 is a sectional view of the improved rotor as taken at one side of its axis, and

Fig. 2 is a reduced, front elevation of the rotor with portions broken away to illustrate details thereof, the View being taken from line 2-2 in Fig. 1.

Referring to the drawing, the presently improved rotor is of the axial air gap type and comprises, essentially, a rotor frame 10, a magnetic core member 11, and a cast winding 12 of squirrel-cage form. Rotor frame 10 is a unitary member which is formed to provide a disc body 14 having a Shaft-mounting hub structure generally indicated at 15. The hub 15 includes an annular hub portion 16 projecting from one side of the body 14 and an annular hub portion 18 projecting from the other side of the body, the latter terminating in a shaft seating portion 19 receiving the end 20 of the rotor shaft 22 to which it is keyed or pinned, as by the pin 23, for rotation of the rotor and shaft as a unit. The hub portion 16 presents an internal bore 24 providing access to a reduced linternal bore 26 formed partly in hub portion 16 and in hub portion 18, bore 26 receiving an anti-friction type bearing unit indicated at 27, for rotatably supporting the rotor on a stationary part indicated at 28 in broken lines of the stator (not shown) with which the rotor cooperates.

'I'he rotor frame body 14 provides an annular planar surface or face 30 on the side thereof from which the hub portion 16 projects, such face being in a plane transversely of the rotor axis and normal thereto. Integral with the opposite side 31 of the body and the hub portion 18 are a plurality of fan blades, one of which s shown at 32 in Fig. 1. Body surface 30 affords a mounting seat portion for the rotor core member 11 which, in rotor assembly, has its back planar side 34 in surface abutment with the frame face 30. The core as shown, is an annular, laminated member of magnetic material, and preferably constructed of a single strip of sheet core iron punched to provide winding slots and wound in coil form. Construction of such a core may be in accordance with the teaching of Letters Patent 2,123,350 to G. R. Anderson. The core thus produced, has the back surface 34 heretofore noted, a parallel planar air gap face 35, inner and outer circular peripheries 36 and 38 respectively, and Winding slots 39 each extending to the gap face, as at 40 (Fig. 2) and open at the inner and outer core peripherles.

Location of the core on the frame seat portion 30 such that it will be in spaced, concentric relation to the frame hub portion 16, on a center coincident with the rotational axis of the frame, is attained by hub projections or anges 42 (three being shown in the present embodiment, Fig. 2) engaging the inner periphery 36 of the core. The projections or flanges 42 are generally radially outstanding on the outer circular surface 43 of hub portion 16, and are equally angularly spaced about the hub, as shown in Fig. 2, and spaced outwardly from the body surface 30 as Shown by Fig. l. Each projection is elongate in the circular direction of the hub, and provides a curved peripheral edge or face 44 the curvature of which is on a radius having a center coincident with the rotational center of the rotor frame, and opposite end margins 46 which may be substantially radial or directed inwardly, as shown, at an acute angle to a radius. These projections or flanges 42 having the curved edges 44 in Contact with the inner periphery 36 of the core, thus attain the desired centering of the core and serve in addition, as core mounting seat means in cooperation with the frame seat 30, and as assembly locking means in a manner presently to appear.

In order to facilitate formation of the present unitary rotor, it is important that the rotor frame as now described, be constructed to afford both positional and dimensional accuracy of its parts, particularly in regard to the planar mounting face 30 and the hub-carried projections 42. To such end, advantage is taken of the now well-known shell-molding process to produce the rotor frame as a shell-mold cast member of suitable material, such as iron or if desired, a non-magnetic metal. The resultant cast frame, presenting an improved casting characterized by uniform metal density and smooth, accurately formed surfaces, thus materially reduces the extent of any machining which may be necessary, as at the body surface y30 and projection edges 44, for accurate core seating.

Having the rotor frame and core member each formed as now described, the core is positioned on the projections 42 and in abutment with frame body surface 30, and the assembled parts are then placed in a mold for casting of the rotor winding 12 thereto. The winding, which may be of copper, aluminum or other suitable or desired conducting material, is cast preferably by centrifugal casting. For example, centrifugal casting thereof may be attained in accordance with the teachings of Letters Patent 2,304,067 to G. R. Anderson. The resulting cast winding provides an outer end ring 50 in cast connection to the outer periphery 33 of the core and to the outer annular face portion 51 of frame face 30 exposed beyond the core member; an inner end ring 52 in cast connection to the inner periphery 36 of the core, to the inner exposed portion 54 of frame face 30, and to the hub projections 42, the latter thus being embedded in the cast winding end ring 52, and winding bars (such as bar 55 shown in Fig. l) filling the core slots 39 and integrally joining the end rings 50 and 52. The winding 12. as cast, thus effects a secure assembly connection of the rotor frame and core, wherein the projections 42 embedded in cast end ring 52 effectively key or lock the casting, and hence the core 11, to the frame and its hub portion 16.

It will be appreciated now that the present improvements alford an electrical machine rotor characterized by simplicity and greater dimensional accuracy of construction, and by a unitary structure wherein the frame and core members are rigidly retained in assembly by the cast Winding, as in the manner described.

Having described and illustrated one preferred embodiment of the invention, it is to be understood that various alterations and modifications may be made therein without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. A rotor for an electrical machine of axial air gap type, comprising a rotor frame having a hub and providing a core-engaging surface, an annular magnetic core on said frame surface, flange means on said hub and in engagement with the core solely at its inner periphery, 1ocating the core concentrically of the hub, and a Winding of conducting material in cast assembly to the core, rotor frame and flange means, securing the frame and core in rigid assembly.

2. A rotor for an electrical machine of axial air gap type, comprising7 a rotor frame having a hub and providing a core-engaging Surface, an annular slotted magnetic core on said frame surface, said core having a circular inner periphery, integral hub projections equally spaced about the hub and spaced from said frame surface, said projections engaging the said circular inner periphery of. the core and locating the core concentrically of the hub, and a winding of conducting material in cast assembly to the slotted core, rotor frame and projections, securing the core and frame in rigid assembly.

3. A rotor for an electrical machine of axial air gap type, comprising a rotor frame having a hub providing a circular outer surface, said frame providing a planar core-receiving surface normal to the axis of the hub, an annular core on said planar surface, said hub having integral elements projecting radially from said outer hub surface and spaced axially from said planar surface, the elements engaging the core at its inner periphery and locating the core concentrically of the hub, and a Winding of conducting material in cast assembly to the core, frame and elements, securing the frame and core in rigid assembly.

4. A rotor for an electrical machine of axial air gap type, comprising a rotor frame providing a disc body and a central hub, said body having a planar core-mounting face normal to the rotor axis, said hub including a shaftengaging portion and a hub portion projecting axially from the planar face of said body, the hub further pro- Cil viding an axial bearing-receiving recess, a plurality of iiange elements radially outstanding on said projecting hub portion and spaced from said planar face, an annular slotted core member of magnetic material, positioned in abutment with said planar body face and having its inner periphery engaging said flange elements, said ilange elements disposing the core member in a position concentric of said hub portion, and a cast winding providing an outer end ring in cast connection toy the frame and the outer periphery of the core member, an inner end ring in cast connection to the frame, the inner periphery of the core member and said flange elements, and Winding bars in the slots of the core member and integral With the end rings, said cast Winding thereby securing the frame and core member in rigid assembly.

5. A rotor member for electrical machines of axial air gap type, comprising a unitary, shell-mold cast rotor frame providing a hub, a disc body having a planar face normal to the axis of the hub, the hub including a hub portion projecting from said planar face, and liange elements radially outstanding on said hub portion and spaced from the planar face, said rotor frame being characterized by smooth as-cast surfaces; an annular core of magnetic material, having planar front and back surfaces and slots open at the front surface and at the inner and outer peripheral surfaces of the core, said core being disposed on the rotor frame with its back surface against said planar face and its inner peripheral surface in seating engagement with said flange elements, the flange elements seating the core concentrically of said hub portions; and a body of conducting material in centrifugally cast assembly to the core and rotor frame, providing an outer end ring embracing the core over its outer peripheral surface, an inner end ring in engagement with the inner peripheral surface of the core and with said hub portion and flange elements, and bars in the core slots between said end rings, said conducting material body as cast, securing the rotor frame and core in rigid assembly.

References Cited in the le of this patent UNITED STATES PATENTS 1,934,981 `Johnson Nov. 14, 1933 2,245,577 Dieckman June 17, 1941 2,490,021 Aske Dec. 6, 1949 2,510,917 Turner et al. June 6, 1950 2,740,910 Fleischer Apr. 3, 1956 2,880,335 Dexter Mar. 3l, 1959 Disclaimer 2,956,189.EZwwd J. Buss, Guy Russell Famke?, J 07m H. Gwwes, and Geom/e E. ODoowld, Freeport, Ill. 'ELECTRICAL MACHNE ROTOR. Patent elated Oct. 1l, 1960. Disclaimer filed Jan. 3, 1966, by the assignee, The I miie/rial E lef/Wie Compa/ny. v Hereby enters this disclaimer to the remaining' term of said patent.

[Oycial Gazette May 24,1966] Disclaimer 2,956,189.-E6Zwm"d J. Buss, Guy Russell Fanshee", J 07m H. Gv'owes, and George E. ODmmld, Freeport, Iii. ELECTRICAL MACHNE ROTOR. Patent dated Oct. 11, 1960. Disclaimer iled Jan. 3, 1966, by the asszignee, The I mpem'al Eleetw'e @empa/ny. Hereby enters this disclaimer to the remaining' term of said patent.

[Oez'l Gazette May 24, 1966.]

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