US2639087A - Axial flow fan - Google Patents

Description

May 19, 1953- C, F, GOEDE 2,639,087

AXIM. FLow FAN Filed Nov. 4, 194'7 Patented` May 19, 195.3-

FLOW FAN Charlesr F. GoedepNew Philadelphia, Ohio, assignor vtoHJoyManufacturing Company, a corporation of Pennsylvania Application November 4, 1947, Serial No. 784,015

s 1` This invention relates in general to axial flow fans and drives therefor, and in particular to ar-" supported with respect to the fan and motor casing that the fan may operate `with minimum tip clearance between the fan and the peripheral wall of the fan chamber. From another aspect,

my invention relates to a method of rcoaxial assembly of a -fan in the fan chamber of a fan and motor casing. A o o The efficiency of axial flow fans of` the vane axial type is determined in great degree by the running clearance between the tip of the -fan blades and the inner Wall of the fan chamber, and if this clearancecan be maintained at a uniform minimum of a few thousandths of an inch, a highly advantageous result, from the aspect of efficiency, may be'obtained. In the volume production of small fans 'utilizing motors built by volume production methods, it is highly irnprobable that there will beavailable peripheral surfaces on the motor casings so perfectly coaxial with the axis of rotation of the fan driving motor shafts as to permit, through the mere cooperation of such surfaces with matingly shaped internal surfaces on the fan and motor casing, the desired centering of the fan in the fan chamber of the fan andmotor casing.` The manufacturer of relatively inexpensive fans on a volume production basis, with utilization of Volume production methods, will find his production costs seriously increased, if it is necessary to take the motors which are to be incorporated in the fans and turn upon them surfaces in true coaxial relation with the motor shafts. If such a manufacturer can avoid this operation and yet effect a proper centering of the motor shaft with respect to the fan chamber by a method which will not itself add materially to production costs, there will be a considerable advantage obtained, and, particularly if mono-bloc fan and motor housings are utilized, so that distortion in use is unlikely,`

a permanent minimum running clearance may be expected.

It is an object of my invention to provide an improved axial flow fan. It isl another object to provide an improved axial flow fan of the type in which the motor is carried by the fan and motor housing. It is a further object to provide an improved axial flow fan, having'a driving ymotor carried by a fan and motor casing and employing improved means for maintaining the motorr with its driving shaft coaxial lwith the internal ls claims.; (o1. 23o- 117) Wall of the fan chamber which is provided in the fan and motor casing. It is still another object of the invention to provide an improved axial flow fan having improved means, which require no special machining of surfaces of revolution on the motor casing, for maintaining the fan driving motor with its shaft in coaxial relation with the inner Wall of the fan chamber of a fan and motor housing, in such manner that the tip clearance between the fan and such wall may be maintained at a small minimum.` It is still another object of the invention to provide an improved axial flow fan of the type in which the driving motor is carried by the fan and motor housing, in which fan the centering of the motor-shaft with respect to the fan chamber is accomplished by bedding a portion of the motor casing in a material plastic during assembly of the motor in the fan and motor casing, but which material hardens into a rigid mass, and which not only provides a seat for the motor casing but also, as it were, keys itself into a locked relation to the fan and motor casing in sucha manner that removall of thek motor, if necessary, and its replacement with its shaft in true coaxial relation to the Vfan chamber, is possible. It is still another object of my invention to provide an improved method for the volume production and precision assembly of axial flow fans. Other objects and a fuller understanding of the invention may be had by referring to the following discourse and claims, taken in conjunction with the accompanying drawings.

ln these drawings, y

Fig. 1 is a longitudinal section through a fan and motor casing mounted on a jig` used in effecting assembly.. 1 f

Fig. 2 yis a similar view with a plastic ring positioned in the motor housing preparatory to the insertion and securing of the motor in such housing. l

Fig. 3 is a view similar to Figs. 1 and 2, showing the motor inserted in the motor housing, and the plastic substance reshaped by pressure, and the parts ready for the application'of holding means to maintainthe motor in desired position.

Fig. 4 is a ,view'showingl the fan assembly removed from thel jigafter the motor yhas been fixed indesired relation to thev fany and motor housing.

Fig. 5 is a View in longitudinal central section',y through the complete. fan, with the fan rotor nected to an inner annular wall portion I2 by a series of radially extending vanes I 3, these varies being appropriately spaced about the axis of the casing and shaped to produce the desired effect upon the flow of the air displaced by the fan later described. The inner wall I2 constitutes a motor housing and surrounds a chamber` I4 in which a fan driving motor I5 is adapted to be received, and the wall I2 has connected integrally with it a radially extending wall portion I6 traversed by openings I'I, through which studs or the like may extend, and the wall I6 also has a central openingV IS, through which a noseportion I9 of smaller diameter than the :overall diameter of the motor I5 may extend. The surf-ace of the wall I5 which is nearer the chamber I4 may desirablv (but need not necessarily) be made plane and be so disposed that the axis of an internal surface of revolution EI which bounds a fan chamber 22 in the fan and motor casing is perpendicular to it. The fan and motor casing I0 may desirably be cast or molded, 4so that the same may be free of distortion.

Ordinarily the surface 2| will be an internal al surface, but it is obvious that any other surface of revoiution permitting the assemblage of an appropriately shaped fan rotor in close running rela-tion to the wall 2l might be employed` subject to the condition that, if a jig of the character here illustrated is to be used, such surface shall be adapted readily to receive and closely t upon a corresponding external surface formed upon the jig. Y

Figs. 1 to 3 show a jig 25 having `openings 25 extending through it so that the socket end of a torque wrench or the like may be inserted through them. This jig has two coaxial surfaces of revolution, `an internal surface of revolution 27 formed closely to t the` shaft of a motor which is to be positioned in the fan and motor housing, and an external surface of revolution 28, adapted closelyto fit within the internal surface of revolution l2I. When the fan and motor casing is positioned with its surface '2l snugly surrounding the surface 28 it will b e evident that the surface V2l will be coaxial with the surface 2I, and. therefore that a motor shaft which closely fits the surface 21 will be coaxial with the surn face 2 i., with the result that if, while the shaft vof the motor is so held, the body of the motor can be securely xed within the chamber i the motor shaft will remain in coaxial relation 'to the wall 2i when the jig 25 is removed from 'tl e fan and motor casing i8, or vice versa. Moreover,

a fan, the tips of whose blades lie in asurface of revolution coaxial with a motor shaft receiving socket in the fan hub, which socket is a close t for the motor shaft, will, when assembled upon the shaft of the motor, be Ycoaxial with the fan chamber wall 2i and capable of operating with a very lsmall but safe clearance within the fan chamber.

To secure the lfan driving 'motor in position in the chamber I4 with the motor shaft coaxial with the wall 2|, I employ a material which may be positioned in the formof a 'plastic layer between an end surface 30 of the motor 'I 5 andthe opposed surface 20 of the wall IG. VThis material may assume many forms, subject only to the conditions that 4it vbe suitably plastic when put in place and hardenable with reasonable speed and remain hard at the temperatures vencountered in use. It may, for example, b'e iron 'cement, ormay be somewhat like the well known Smoothom Ibut very desirably `it may be in the form of a thermoplastic ring, which is heat softenable and which may be deformed under pressure sufliciently to cause it to be squeezed up around the lateral edges of the motor head and also to key into the openings I'I through which the mounting studs for the motor extend and into the opening I8 around the nose I9. This material, when in the lform of a perforated disc, after being softened by heat, may be placed in the end of the motor housing and squashed into the desired relation to the motor housing either by applying a force on the end of the motor or by applying tension to the studs provided for xing the motor in position. It will be understood that if the forming or moulding of the plastic is to be accomplished by traction on the studs, openings 25 must extend completely through the jig to permit a socket wrench to have access to the holding studs, but if it be desired simply to apply pressure axially upon the end of the motor I5, while the end of the casing I0 rests upon a shoulder S on the jig 25, to cause the plastic layer to be pressed into the desired shape, the openings 26 may merely be sockets sufficiently long to permit the motor mounting studs to enter them without interference, and, after the jig is removed, following the hardening of the plastic substance, lock washers and nuts may be applied to the studs, with the exertion of uniform torques, without disturbing the coaxial relation of the motor shaft with the fan chamber surface 2 I.

It will be noted that in the specific construction illustrated, the motor I5 is provided with mounting studs 33 to which lock washers 34 and nuts 35 are adapted to be applied.

It will further be noted that the motor casing and the inner annular wall of the housing have spaced, respectively external and internal, surfaces of revolution, the latter surrounding the former, which surfaces are cut by common planes to which the axis of the motor shaft is perpendicular, and that the hardened plastic material, in the assembled relation of the fan parts, extends between and simultaneously contacts said surfaces of revolution and thereby provides radial support for the motor casing in the housing.

Reviewing the disclosures of the figures of the drawings, it will be observed that in Fig. 1 the fan and motor casing I0 has been mounted on the jig 25 in such a manner as to position the surface 2I in coaxial relation with the surface 2. A plastic disc 37, one softenable at a te. perature below the boiling point of water and adapted to become hard upon cooling and to remain hard at temperatures above any which would normally be developed during the operation of the fan, is illustrated in Fig. 2 upon the surface 20, with a central opening 33 in the plastic disc, of smaller diameter than the opening I8, coaxial with the latter opening, and with stud receiving openings 39 of smaller diameters than the stud receiving openings II overlying these latter openings. In Fig. 3 the motor I5 is shown as having been inserted in the chamber I4, and pressure applied to its upper end has caused the plastic disc 31 to beldeforrned so that an annular portion thereof, 40, has been projected into the opening I8. Other annular portions 4I thereof have been projected into the annular spaces between the studs 33 and the walls vofthe openings Il, and a further annular portion 42 thereof has been projected or squeezed outwardly, and at least partially surrounds the convex outer edge of the motor head through which the motor shaft extends. In Fig. 4, "the yfan has been; removed frm ihgrig 25,311.4; prior to this, preferably, ,the loclpwashers v,1,14 and nuts 35 have been appliedto ,the studs L33 and'further pressure has been applied to the plasticA disc'31 to increase the depth of the seatingof the motor casing in the plastic body, and the plastic has been permitted to harden sorfthat further deformation as the assembly is handledwill not occur. It will be understood that the nutspand lock washers may be applied, and preferably are applied, while the jig is still in position, but that this is not necessarilydone` at that time- In Fig. 5 there willbe observed the location of a fan 50 upon the rotor shaft with the fan blades y5l arranged to operate with a close and substantially uniform clearanceat 52, between their edges and the internal surface 2l. y y

As a result of this invention, it will beobselved that I have provided avery simple `and effective method for the production of high efficiency fans, utilizing comparatively inexpensive motors, without special machining/of the casings of, these motors, the only prerequisite to satisfactory results being that the bearings of the motors be adapted to maintain the motor shaft so that it shall be incapable of much radial displacement of its axis in operation. In otherwords, the bearings should hold the shaft without much play. It will be also obvious thatfthe rarrangement is one in which, through very simple operations, assembly can be accomplishedthat the use of plastic discs or other plastic bedding mate rial is a simple andinexpensive process, that the inter-keying of the plastic and the casing, etc. provides for a very effective and secure centering of the motor shaft in the motor casing with respect to the fan chamber in the` fan and motor housing, and, in other Words, that both an improved, inexpensive, simple, and effective method of fan construction providingyfans of highy aerodynamic efnciency, andan improved `fan construction per se of high aerodynamic efficiency,

are provided. c

While there is in this application specifically described one form which my invention may assume in practice, it will be understood that this form has been shown for purposes of illustration and that the invention may be modified and vernbodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire tolsecure by Letters Patent is: 1

1. In combination, in an axial flow fan, a fan and motor housing comprising an outer annular wall and an inner annular wall in substantially concentric relation, the outer annular wall'providing a fan chamber and the inner annular Wall a motor housing, and a plurality of circumferentially spaced vanes connecting said walls in fixed spaced relation, said inner wall having a radially inwardly extending portion to provide a transversely extending surface toward which a motor received in the motor housing moves upon insertive movement, a motor having a casing and a rotating shaft, said motor casingl and said inner annular wall having spaced, respectively external and internal, surfaces of revolution, the latter surrounding the formen which surfaces are cut by common planes to whichthe axis of said rotating shaft is perpendicular, a fan for which said shaft constitutes both a support and driving means, said motorcasing having a surface thereon facing said transversely lextending ufffif Whllcsd .moiQr ,Gesine isiarraneed with- 6 the. motor .Chamberiyarid .mearisifor fix-iris' the motor relative to the fan and vmotorhousingwith the. fari .centered in .the fari member. including a hardenedt'hermoplastic a'nnulus` having'llmporj rions extending. between and Simultaneuslv corrtacting said surfaces of revolution andthereby providing a radial support Afor the motorcasing and other'portions extending between said transe verse surface and the oppositely facingsurface of the motor casing and `means for maintaining said plastic annulus under compression between saidy transverse surface and the oppositely facing surface of the motor` casing. u g 2,A In combination, in an axial now fan, afan andA motor housingcoxnprising kan outer annular .wall .and aninner annular ,Wallin substantially concentric relation, the outer annular wall prof viding a fan chamber and the inner annular ,Wall a motorhousing, and a plurality of circumferf entially spaced vanes connectingvsaid walls in fixed spaced relation, said inner wallfhavinga radially` inwardlyyextending portion open at its center and iproviding a transversely `extending surface toward which a motor received in the motor housing moves upon insertive movement, a motor having acasing and a rotating shaft, a ,fan for which saidnshaftfconstitutes both a support and driving means, said motor casing having ay surface thereon facing, said transversely extending surface lwhen said motor casing vislarranged within the motor chamber and having `a projecting portion receivable in the open center of said radially inwardly extending portion, and means for fixing the motor relativeto the fan and motor housing with the fan centered in the fan chamber, including.v a hardened plastic annulus having portionsproviding radialsupport for the motor casing with respect to said rhousing both at the periphery thereof and at said projecting portion, and means for vxnaintainingsaid plastic annulus under compression between said transverse surface andthe oppositelyy yfacing surface of .the motor casing. n

3. In combination, in an axial owfan, afan and motor housing comprising an outer annular wall and an inner annular wall in substantially concentric relation, the outer annular Wall providing a fan chamber and the inner annular wall a motor housing, and a plurality `of circumferene tially spaced vanesconnecting said walls in xed spaced relation, said inner wall having a radially inwardly extending portion providing a transversely extending surface toward which a motor ,received in the motor housing moves upon insertive movement and having motor holding stud receiving openings, a motorhaving a casing anda rotating shaft, a fanfor which said shaft constitutes both a support anddriving means, said motor casing havinga surface thereon facing said transversely extending* surface wheny said motor casing is arranged Within the motorchamber, and having projecting studs extending throughwsaid stud'receiving openingsfor4 fixing the motor relative to the fan and motorho'using with the fan centered in the Vfan chamber, nuts on said studs,` anda hardened plastic annulus yhaving portions received in lsaid openings around said studs and through their cooperation with the peripheries of said studs andthe walls of said openings fixing the position o f said studs in said openings, said hardened plastic annulus maintained under compression, by said studs,between said surfaces. l ,4f In, CQmbllaiOn, ,ill-arr axial flow fama fan all? 1119i?! @Qll .C Orriprirrs ,an .Outer annular wall andan inner annular wall in substantially concentric relation, the outer annular wall providing a fan chamber and the inner annular wall a. motor housing,V and a plurality of circumferentl'ally spaced vanes connecting said walls in fixed spaced relation, said inner wall having a radially inwardly extending portion providing a transversely extending surface toward which a motor received in the motor housing moves upon insertive movement and having motor holding stud receiving openings, a motor having a casing and a rotating shaft, a fan for which said shaft constitutes both a support and driving means, said motor casing having a surface thereon facing said transversely extendingsurface when said motor casing is arranged within the motor chamber, and having projecting studs extending through said stud receiving openings for xing the motor relative to the fan and motor housing with the fan centered in the fan chamber, nuts on said studs, and a hardened plastic annulus having portions received in said openings around said studs, and other portions extending between the motor casing and a surrounding surface on said housing and providing a radial support for the motor casing relative to said housing, said annulus maintained under compression, by said studs, between said surfaces,

5. In combination, in an axial flow fan, a fan and motor housing comprising an outer annular wall and an inner annular wall in substantially concentric relation and a plurality of circumferentially spaced vanes connecting said walls and maintaining them in spaced relation, said outer annular wall extending beyond one end of said inner annular wall and circumferentialiy enclosing a fan chamber and said inner annular wall circumferentially enclosing a motor chamber and having a radially inwardly directed Wall providing a transversely extending surface, a motor having a casing and a rotating shaft, a fan for which said shaft constitutes a support and driving means, said motor casing having a surface thereon facing said transversely extending surface when said motor casing is arranged within said motor chamber and its shaft is supporting said fan within said fan chamber, and means for fixing said motor casing relative to said fan and motor housing with said fan centered in said fan chamber including studs carried by said motor casing, openings in said radially inwardly directed wall through which said studs extend, nuts on said studs, and a hardened plastic material molded between said surfaces and at least partially lling the spaces between said studs and the walls of the openings in said radially inwardly directed wall and through their cooperation withy theperipheries of said studs and the walls of said openings fixing the position of said studs in said openings.

6. Incombination, in an axial flow fan', a fan and motor housing comprising an outer annular wall and an inner annular wall in substantially concentric relation and a plurality of circumferentially spaced vanes connecting said Walls and maintaining them in spaced relation, said outer annular wall extending beyond one end of said inner annular Wall and circurnferentially enclosing a fan chamber and said inner annular wall circumferentially enclosing a motor chamber and having a radially inwardly directed wall providing a transversely extending surface, a motor having a casing and a rotating shaft, a fan for which said shaft constitutes a support and driving means, said motor casing having al surface thereon facing said transversely' extending surface when said-motor casing is arranged within said motor chamber and its shaft is supporting said fan within said fanichamber, and means for fixing said motor casing relative to said' fan and motor housing with said fan centered in said fan chamber including. studs carried by said motor casing, openings in said` radially inwardly directed wall through which said studs extend, nuts on said studs, said motor having a projecting portion surrounding said shaft and said radially inwardly directed wall having another opening into which said projecting portion extends, and a hardened plastic material molded between said surfaces and at least partially'lling the space between said projection and the w'all of the opening into which it? projects and through its cooperationy with the peripheral wall of said projecting portionl and th'e wallv of said another opening fixing the position of said projection radially with respect" to said opening. y

7. In combination, in an axial flow fan, a fan and motor housing comprising an outer annular Wall and an inner `annular wall in substantially concentric relation and a plurality of circumferentially spaced' vanesl connecting said walls and maintaining them in spaced relation, said outer annular wall extending beyond one end of said inner annular wall and circumferentially enclosing a fan chamber and said inner annular wall circumferentially enclosing a motor chamber and having a radially inwardly directed wall providing a transversely extending surface, a motor having a casingl and a rotating shaft, a fan for which said shaft constitutes a support and driving means', said motor casing having a surface thereon facing said transversely extend'- ing surfacey when said' motor casing is arranged within said motor chamber and its shaft is s'upporting said fan' within said fan chamber, and means for fix-ing said motor casing relative to said fan andmotor housing with said fan centered in said fan chamber including studs carried by said m'otor casinggopen-ings in said radially inwardly' directed wall' throughy which said studs extend, nutson said studs, said motor having a projecting portion surrounding said shaft and said radially inwardly directed wally having another opening into which said projecting portion extends, and a hardened plastic material molded between said surfaces and at least partially filling the space between said projection and the wall of the opening into which it projects and also at least/partially lling thespaces between said studs and the walls of the openings through which the studs extend; such material through its filling portions fixing the motor casing against lateral displacement relative to said housing.

8. In combination,V in an axial ow fan,` a fan and motorhousing comprising anouter annular wall and an inner annular wall inl substantially concentric relation and a plurality of circumferentially spaced vanes connecting said walls and maintaining them in spaced relation, said outer annular' wall extending beyond one end of said inner annular wall and circumferentially enclosing a fanchamber and said inner annular wall circumferentially enclosing aA motor chamber and having. a radially inwardly directed wall providing a transversely extending surface, a motor having a casing and a rotating shaft, a fan for which said shaft constitutes a support andl driving means; said motor casing having a surface thereon'A facing said transversely extend'- ing surface when said motor casing is arranged within said motor chamber and its shaft is supporting said fan within said fan chamber, and means for xing said motor casing relative to said fan and motor housing with said fan centered in said fan chamber including studs carried by said motor casing, openings in said radially inwardly directed wall through which said studs extend, nuts on said studs, sai-d motor having a projecting portion surrounding said shaft and said radially inwardly directed wall having another opening into which said projecting portion eX- tends, and a hardened plastic material molded between said surfaces and at least partially lling the space between said projection and the Wall of the opening into which it projects and also at least partially lling the spaces between said studs and the walls of the openings through References Cited in the le of this patent UNITED STATES PATENTS l0 Number Name Date 1,898,613 Apple Nov. 22, 1932 1,932,391 Apple Oct. 31, 1933 2,089,601- Faber Aug. 10, 1937 2,134,142 Orear Oct. 25, 1938 15 2,178,401 Meyerhoefer Oct. 31, 1939 2,423,750 Benson July 8, 1947 2,427,032 Troller et al Sept. 9, 1947 2,494,772 McElroy Jan. 17, 1950

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