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`%
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`Europaisches Patentamt
`European Patent Office
`Office européen des brevets
`
`ttl
` l l I nnn
`(i) Publication number: 0 565 312 A2
`
`a)
`
`EVROPEAN PATENT APPLICATION
`
`@i) Application number : 93302596,7
`@) Date of filing : 04.04.93
`
`67) int. CLS: HO2K 7/14, HO2K 5/04,
`HOZK 21/12, HOZK 14/00,
`HO2P 6/02
`
`
`
`G0) Priority : 06.04.92 US 863900
`~
`@ Date of publication of application:;
`13.76.95 Bulletin 93/41
`
`84) Designated Contracting States :
`AT DE ES FR GB SE
`
`i) Applicant: GENERAL ELECTRIC COMPANY
`4 River Road
`Schenectady, NY 12345 (US)
`
`2 inventor: Erdman, David Marvin
`™ 5420 Arehwood Lane
`Fort Wayne, Indiana 46825. (U8)
`inventor: Yoder, Dale Frederick
`8323 Redstone Drive
`Fart Wayne, Indiana 46835 (US)
`inventor: Tatman, Richant Scott
`2318 White Hall Drive
`Fort Wayne, Indiana 46845 (US)
`inventor: Molnar, David Thomas
`2128 Wawonaissa Trai
`Fort Waynes, Indiana 46809 {US}
`
`t74} Representative : Pratt, Richard Wilson et al
`London Patent Operation G.E. Technical
`Services Co. inc. Essex House 12/13 Essex
`Street
`Lendon WC2R 2AA (GB)
`
`
`a) integral motor and: control.
`
`intagral alec-
`low-power
`67) Aq energy efficient
`ponically commulated fan: motor and sontral
`clrout assembly mounted an a: oircut board for
`use in relrigerators utilizing a Hail sensor:
`io
`provide positional control signals for .sequeriial
`energization of the windings with the Hall sen-
`sor. energization being pulsed, and the motor
`stator windings energized only during a portion
`of the period, when rotational torque produced
`by the energization is greatest in order to re-
`duce the power input to the assembly. Integrally
`moked
`omultHfunction
`components.
`including
`he ‘coll Dobbin, ground pin, Hal sensor holder,
`motor bearing o8 well covers, and assembly
`houging provide positioning, support, and sec-
`uring assistance alang with electrical and. mag-
`nelic operative connections and positioning. A
`capactively coupled bridge power
`supply is
`provided tO further reduce power consumption,
`and the motor is srofected under fault and ‘stall
`conditions by a. current
`limiting circuit and a
`fimed retry circuit, and the rotor and stator are
`designed for adequate starting torque in a ref
`rigerator, Power js supplied to fhe moter wind-
`ings
`trough a voltage
`dropping
`capacitor
`
`connected in series therewith,
`
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`Jouve, 18, sue Saint-Denis, 75003 PARIS
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`BACKGROUND OF THE INVENTION
`
`The present invention relates to an integral, low power, high efficiency motor and control partioularly suit-
`able for use in applications where high reliability and high efficiency are particularly important, such aa, for
`example, household refrigeration systems.
`in conventional refrigerators of the residential a househald type a. comepresser pumps a circulating refrig-
`erant such as freon to a condenser coil where heat is extracted, The condanser coil is typically positianed an
`the exterior of the refrigerator, and air circulates over and around the condenser coils (with or without assis-
`iance froma fan or blower) to extract heat iherefram:. The cocied refrigerant is then circulated through an-evap-
`orator cod. within the refrigeratar, typically ina freezer compartment, ta cool the space within the refrigerator.
`The refrigerant then circulates to the conmipressor and thence back to ihe condenser. This cyde continues until
`the temperature within the refrigerator reaches a desired preselected temperature as sensed by a thermostat
`oF temperatures contrel, A small. moter driven evaporator fan is nermally provided within tha freszar compart-
`mentto circulate ait over the evaporator.colls, throughthe freezer campariment, atid bebveen ihe freezer com-
`partment and the remainder of the refrigerator
`& conventional fan motor is typically a low power motor having @ powerinput in the range af 8.5:to 13.5
`watis with an output power of approximately 2.6 watts. Thus, it will be understocd.that the efficiency. of con-
`ventional evaporatorfan motors is generally in the arder of less than 30%:ft also should now be understood
`that 76% or more of the electric power supplied to such motors is converted te heat within the refrigerator{or
`freezer compartment, and such heatirust be removedfran the interiaf of the refrigerator by the refrigeration
`system. Thus, inefficient evaporator fan motor operation is undesirably jever-aged , becauss each watt of heat
`released in the freezer increases the cooling and thus power demands.on therefrigerant compressor motor
`arid the remainder of the system. Typically, with dfher things being held constant, {he reledse of one extra
`watt-af heat inside a reirigerator requires in excess of one extra watt of comoressor motor power to remove
`sach such watt of heat generated within the refrigerator. Even with a highly efficient refrigeration system it
`would typically require in excess of 1.2 additienal watis of ingut power to compressor and condenserfan motors
`compensate for each additional walt of power dissipated by an evaporator fan motor inside ihe refrigerated
`compartnent. This amounts to a total sower leverage factor of 2.2.
`One major objective of the present invention is to provide a new and improved motor and contral such that
`the just referred to undesirable leverage can be viewad as.desirable, and used io reducethe overall power
`consuimplion by a refrigeration system. Far example, f one were able to reduce evaporatorfan motorinpul pow-
`ef requirements by an initial Swatts per hour, thenone ceuld reduce the overall refrigerator power requirernents
`by the initial @ watts plus an additional 7 or more watts (at the compressor and. condenser). and this all could
`amount to as much as 90 kilowait hours per year, which could represent as much as 10% of the total annual
`power consumption ofa typical household refrigerator.
`This power reduction is significant, hawever, not only in its cost savings to a consumer over the life-of'a
`refrigerator, but-also in helping to reduce theburning of fossil fuels to generate such power. Moreaver, the power
`savings just mentioned can assist in enabling 2 refrigerator to. meet the power reduction regulations and/or in-
`cenlives of state and federal governmental hodies.
`Publis concern about electrical power consumption, is reflected by proposed legistatian and U.S. Depari-
`ment of Energy (DOE) raguiations, and has emphasized the needto increase the efficiency of household ap-
`pliances to reduce bath the amount af fossil fuel burned, and the need for additional power gansration capacity.
`Public interest and demand is reflected in Energy Guide labels or tags on househald appliances which disclose
`the power requirements and typical cost of operation information.
`A stil further complication in the redesign of some rotors, and particularly refrigerator evaporator fan mo-~
`tors, is the need that the substitute motor fit within the space envelope available in present refrigerator designs,
`since It would be costly to change-existing icoling used In manufacturing refrigerators simply to accommodate
`differently sized motors. Moreover, its desirabieto utilize a high efficiency motor to reglace an existing motor
`for repair purposes, Thus, it is-very desirable that improved motors (and controls when packaged therewith}
`be usable in existing space envelopes,
`jn addition there is growing concern over release ints the atmosphere.of freon refrigerants used in refrig-
`érafors and of chemicafs used: as foaming agents during the manufacture of insulation used in refrigerator walls.
`Concern over the possible damage fo the ozone layer in the earth's atmosphere by CFCs (chloraluorocar-
`bons)}.in the refrigerant is feading to the use of alternate refrigerants. However, presently available alternate
`refriqeranis are jess efficiant than the freon presently used, sa thair use would further reduce the efficiency
`of refigeration systeme. Moreover, the foam. insulation used in the walls of refrigerators typically utilizes CFCs
`as the blowing agent during manufacture, while the usa-of other knows suietitule materials result in ingulations
`with reduced R factors. This all further increasesthe desirability of reducing the amountof heat released by
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`a motor inside a refrigerated enclosure.
`The need to further increase theefficiency of electric appliances has. led to cash incentives. Various state
`or tocal agenciesor utility cornpanies. (such ag in California) offer rebates to new applisnce purchasers pro-
`portional te the amount of energy saved by using the new appliance. This further increases the continuing
`demand and need for refrigerators and other agpliances with increased efficiency.
`As 2 result af the above considerations considerable research and effort has gone into the redesign of
`appliances, including camponents thereof such as mators, in order te increase slaciric efficiencias, and to meat
`present oranticipated environmental concerns, with raguiations and goals aimed al reducing power consump-
`fion by as-much as 30%.
`‘FRus, diwould be extremely desirable to provide an improved high efficiency fan motor for a household
`refrigerator which aiso could be used (with or without modification) as a refrigerant condenser fan motor.
`improved Jow power motors of the type we contemplate for use in refrigeration systems may advantageous-
`ly be of the “brushless do" or “electronically cammutated motor type. However, this type of motor can be dam-
`aged if-the motor stalls, or ceasesto-atiain desired aperaiing speeds. when first:starting, or rotates: at lower
`than rormel speeds under load canditians. In the abserice of a back emf! or vallage- associated with rotation
`of the rotor, the applied ine vallage may cause excessive current flow through the mator windings which may
`exceed the rated currentcarrying capacity of the windings and lead to aver-heating and/orfailure. Accordingly,
`it is desirable to. provide adequate starting torque, and itis also. highly desirable to provide means to detect
`reotey stall, and-to provide adequate restarting torque and/or current limiting in the event of raotar stall:
`Notwithstanding all of the above, in highly competitive markets such as, for example. the household re-
`frigerator marketit is alsa vary important to keep.the cost-of improved motors.to a minimum since many can-
`summers are unwilling, or unable, to pay higher prices for energy saving improvemants, notwithstanding the fact
`that inital costs often are recouped. mary times aver the multiple year life af a machine. Thus, itis important
`that initial costs for improved products be minimized by providing a readily marufacturable design.
`Also, notwithstanding all af the above, itis vary important that motors for equipment having along service
`life (6.g., household refrigerators) exhibit reliable operation and have o long life in Wew of consumer expecta-
`tons and past experiencewith equioment that requires Htile or no maintenance for extended periods of cor-
`tinuous use, We have determined that brushless motors combined with sold state control device circuitry can
`provide the desired good reliability and low maintenance operation.
`
`OBJECTS AND SUMMARY OFTHE INVENTION
`
`Accordingly, a primary object of the present invention is te provide a new and improved, integrated and
`unitary motor. and associated. contral. circuit slaments having improved operating efficiency.
`Another object of the present invention is fo provide a new and improved law power integrated and unitary
`rotor and associated contro! circuit elamants suitable for use in refrigeration systems which is cast efficient
`in operation, yet relatively inexpensive tc manufacturein order to minimize the initial cost of the system.
`Sui another object of he present invention is to provide a new and improved Integrated and unitary low
`power fan motor-and associated motor contrat cieouit which is suitable to. be used as the condenser or evap-
`orator fan motor in refrigeration systems,
`Yet another object of the present invention is to provide an improved high efficiency low powerfan motor
`and santral for use in refrigeration systems which provides adequate starting torque and which detects and
`protects the motor in the event of motor stall.
`Stil yet another object.of the present invention is to provide 2 low power motor and control circuit inwhich
`the fan moter and associated controi cireuitry elements are combined inan integrated design with unified can-
`struction and,structural support, and which may be installed in the space in arefrigsration system normally
`occupied heretoforebyonly. amotor, thus promoting the possibility of direct replacement of existing motors in
`existing refrigeration system designs.
`A further object of the present inveriiion is to provide a new and improved low powered integrated motor
`and control cireauit which is.reliable in operation, and which is relatively maintenance free,
`Still other objects refate ta the provision of a combination of control circuit elements. and-en electric motor
`that is of navel mechanioaf construction, electromagnetic design, and arranged ina unitary package.
`in order & atiain the above and other related objects, ip carrying cul {he present invention in one form
`thereof, a direct current electronically commutated DC fan motorjs integrally assembled on a circuit board that
`also caries control cirouit elements, with a portian ofthe moter passing through:a region of the circuit beard,
`wiih a siater cail positioned to one side of therotor; and-with electranic camponents pasitianed to the other
`side of the rotor.
`
`The components of the assembly inchuide integrally molded multifunction components which assist in the
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`positioning, Supporting and ratention of various alectical and electronic components in proper aperative pos-
`Hions.. The. coil is wound on a bobbin which includes integral means fer positioning and seouring the ool on
`the cireuit hoard, te accommodate self-connecting winding terminals which aiso position, connect, and support
`the coil an the circuit board, and means for positioning and detachably securing the assembied fan motor and
`conitrel circuit within the assembly cover or housing, while at the same-time preventing movement of the as-
`sembly in orthogonal directions.
`Motor ail well covers include integrally malded members that facilitate attachment to the motor and shields
`while also providing a two point axial support system for the integral motor and control assembly within the
`refrigeration system.
`Preferred embodiments of our invention include a fow power brushless motar conirol-ihat utiizes = Hall
`device te sansa the angular positien of the rotor to coniyal the cormmutabon of the windings. The Hall sensor
`is preferably pulsed curing a portion of each cycle of operation and its output is sarnpled for operation and can-
`traf af ihe motor inorder to provide increased efficiancy..tt also is preferred te use solid siate control circuliry
`to: dénergize the field cos of the motor only during the periods of ther greater efficiency dering Bach power
`cycle, and discentinuing the energization during the periods of lowered efficiency inorder fp further realize
`enhanced power efficiency. Another preferred embodiment of the present invention realizes still further effi-
`ciency improvements through the use of a capacitar-feed bridge circuit coupling of the control circuitry to power
`semiconductors that energize the direct current motor.
`A stall of speed sensoris also preferably provided to detect decreased motor speed and motor stall, and
`apply a periodic starting torque pulse: and alse to limit the magnitude and duration of current flow through the
`mator under fault conditions.
`
`Other objects of the present invention and the advantages realized tharefrom will bacome readily apparent
`fram. the following description taken iq conjunction with the accompanying drawings in whish like reference
`characters are usedto describe like parts throughout the several views.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`FIG. 4 is a perspective view, partially cut away, of @ typical household refrigerator incorporating a motor
`and control embodying the praesent invention in one form thereat;
`FIG, 2 is a block diagram ofthe refrigeration system embadiad in the refrigeratorof Fig. 1;
`FIG, 3 is @ perspective view of the integrated uniiary evaporator fan motor and associated contro! circuit
`glaments of FIG. 3;
`FIG. 4 is @ rotated perspective view of the bottom of the package shown in FIG, 3;
`FIGS. 5 and 6. are exploded views of various major components.of FIGS. 3 and 4;
`FIGS. 7 and 8 show the permanent magnet rotor assembly of FIGS. 5 and 6, wilh. FiGS, 7 and.8 bath drawn
`te ascale of about 1.90 timesfill size:
`FIG. 9 shows details of the stator construction of the motor of FIG: 5, drawn to. a scale of about 1.29 thre
`full size;
`FIG. 10 is an enlarged. fragmentary drawingof a portion of FiG. 10 showing the placement and retention
`ofa Hall device sensor within the statar, drawn toa scale of abou! 4.63 times full size:
`FIG. 14 is afragmentary drawing of portions of the DC brushless motor of FIGS. 3-9 showing the statar
`bore configuration and polarization of the permnartent magnet raterand is drawn toa scale of about 2.42
`times full size;
`FIG. 12 is an enlarged view which shows details of the multifunctionceil bobbin part of the mato af FIG.
`&:
`FIG. 13 shows detaifs of the coil windings on the coil bobbin of FIG.. 12,ail drawn to a scale-of about 1.83
`times full size;
`FIG. t4 and enlarged fragmentary FRGS. 154 and 15B show details of ends of the cail windings(of FIG.
`13} fastened ta terminals, and the securing of terminals and windings directly te the conductive runsof a
`circuit board:
`FIGS. 16, 17 and 18 show details of the integral mounting and positioning means on the assembly cover,
`with FiG. 18 Sing a crass section of FIG. 18 along the fine 18,18;
`FIG, 19 is a cross-sectional view of FIG, 3 taken longitudinally through the axis of rotation of the motor,
`drawn toa scale of about 1.43 times full size, and showing details of the unitary motor assembly and canirol
`cirouitry and circuit slernents;
`FIG, 20 is a much enlarged cross section taken through the center of the Hall sensor showing details of
`ihe positioning and mounting of the Hall sensor of FIOS..6 and 19;
`FIG. 27 is a schematic of the aclid state circuitry associated with the Hall sensor and motor field calls,
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`portions of which are shown on FIGS. 4,5, 154, 158, 19 and 20:
`FIG, 22 and associated FIGS. 224, 228 and 22C are block.and lagic diagramsof the circuitry of an inte-
`grated circuit device, shown in FlG. 21, used to control the pulsed energization of the Hall sensar and the
`motor field coils; with FIG. 22 showing the relationship of the ciroults of FKIGS. 22A, 22B and 22C; and
`FIG, 23 fs a plot of motor winding current flow and the torque/power oulput of the assembly of FIG, 18.
`
`DESCRIPTION OF THE PREFERRED EMBODIMENTS
`
`in FIG. 1, a refrigerator 10 is shown incarporating one ambadiment of the presant invention. The refrigerator
`includes parallel outer walls. 2 and inner walis 4 Gwith the space therebetween filed with foam. insulation 5)
`and an upper fwezer- compariment 6 anda lowerrefrigerator compartment &Baors 12 and 14 provide access
`to the compartments. 6, 8. An integralor unitary evaporator fan motor and control circuit assembly 1 which in-
`cludes a motorand associated cantral circuit elements is positioned al the cesar of the freazer compartment 6
`and includes a protective housing or cage inot shawn) enclosing a fan 20 fastened to the shaft 18 of the motor
`16-which is desoritadin-detail below. Althaugh the exact ae low sath may be different tor different refrigerator
`designs, in the equioment shownin FIG. 4, refrigerated air is circulated within the freezer cornpartment 6, and
`through slots 24, 26, and 28 in-the bottom. of the freezer compartment into the refrigerator compartment 8.
`FIG. 2 shows theinfercannection of the major components of the household refrigeration system of FIG.
`4. The interior of reftigerator 10 inchides.a thermostat ar temperature sensor 23 which contfols operation af
`the motor 29 which drives compressor 27. The mator 29 may be of electronically commutated type. if desired,
`through use of electronic commutator 25. Copending United States patent applications, filed February 27,
`1991, entitled “Motor Controls, Refrigeration Systems and Methods. of Motor Operation and Control,” serial
`numbers 07/861,807 and-O7/861 818, by David M. Erdman, ane of the inventors of the present patent appli-
`cation, assigned te the same assignes as the present patent application, and the entire disclosure. of whichis
`incorporated hersin by reference, disclose details of an electronically commmsated motor forrefrigeration. com-
`pressor use which is suitable for-usein the manner depicted in FIG. 2.
`The compressor 2? circulates a refrigerant such as freon sequentially through the condenser call 45, ex-
`pansion valve or nozzls 31, and the evaporator coil’30 to coal the campartments 6 and 8 (see FIG. 1} within
`refrigerator 10, An evaporator fan motor 16 and the evaparator.coll 30 are located within the refrigerator interior
`6,8, typically in the freezer comparimant.6, and fan 20 driven by tha mater 16 blows alr across and through
`the evaporator coil to reduce the temperature of the ak. The. brushless direct current (DC) mator 16 ig-driven
`by an electronic cammuiator control circuit 33 packaged as-a unitary component with the mater 16 (as deseri-
`bed In detail below) and is energized by power supplied along ines 36 and 37 (upon closure of temperature
`sensor23). Asecoand brushiess BC moter 40, may be powered by electronic commuiator 42, if desired, to drive
`condenser fan44 to blow cocling air over the condenser coil 48. The condenser co} 46, fan dd and condenser
`San motor 40 are normally positioned on the rear wall of,-or at the boftorn of, the refrigerator 10 (autsite the
`refrigerator interior}, and the condenser fan motor is energized during the time periods when the compressor
`motor 29 is energized. Thus, femperature sensor 23-controls the periodic demand anargization of the cam-
`pressor motor 28, evaporator fan motor 15 and condenserfan moter 40.
`Referring nextto- FIGS. 3, 4, 9, @ and 19, the majer components of the assembly 1 are positioned or-and
`within & housing, ericiosure, or assembly cover, 50, fabricated of inert resilient plastic to provide an inert and
`alectrically insulating housing. Housing 50 provides electrical isolation and insulation of the electroniccircuit
`components to comply with the “fingér probe” test. and thus heips prevent accidental shock by a consumeror
`serviteperson, The cover 8) is also flame-resistant because of the electronics iavalved, and “pure” farn a
`health consideration because uf the présence of food along with moisture within the refrigerator, A suitable
`material meeting all those requirements has been found to be a polyvinyl chicride available as Gean-87-244
`from the B.F. Goodrich Ca. Posifianed within the housing 30 is the stator 82 and rotor $4 of motor 1S with the
`rofor positioned within the central region of the housing. The laminated stator core 360 extends ink: one end
`region of the housing caver 50 with the cail bobbin 56.and-stator coil 58 positioned around the laminations of
`coil core 390,
`Also positioned within the housing $0 and located belaw hinged cover GG; of the side of the rotor $4 op-
`posite coil &8, ara electronic components aueh as control circuit ekements 200 and 367 (see FIGS. 5 and 16-
`78) on printed circuit board 336, which are protected and isalated by the hinged caver. The hinged cover 66
`rotates about hinge 62 that is molded aa an indanted seam or crease integral with-and part of the housing 50.
`Resiient fingers.64 and 66, siso maided integral with the housing 50, an each ead of hinged cover 60, extend
`thraugh slotted passages 68 and 7G molded inthe skies of [he housing §). The resilient fingers 64 and.66 are
`coritoured to provide-a cariming action such that the application of manual pressure to the hinged cover 60
`forces the resilient fingers or jaws $4 and 66 towant ane another untl the tapered extensions 74 and 76 extend
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`through the siots 70. and 72, whereupon they snag away from each other and overlie the inner.ends of slots
`68. and 70, respectively, securing the hinged cover-firmly in place. Thehinged cover 60 may be opened by
`applying pressure te the tapered extensions 74 and 76 af the resilient fingers 64and 68, respectively, such
`that they move toward one another after which they can be withdrawn through slots 68 and 70, respectively,
`to the spen cover position.
`FiG, 4 shows the bottern of the housing 50 which has been rotated from the positian shown in FiG. 3to
`better illustrate features of its construction. It is ta be noted that the tapered axtensions 73 and 75 molded in-
`fegral with the bobbin 55 (also see FIG. 12) on which the windings of coil 58 are wound are shown positioned
`within stots 78 and 80 in the end of moter housing 60. When the integral motor and contra! circuit assembly 4
`is pushed into the assembly cover 56 {also see FIGS. 16- 18), the tapered surfaces of exiensians 73 and 75
`provide a camming action which initially deforms the end 84 of the resilient assembly cover auhward, enabling
`the assembly to be inserted into the assembly cover until the extensions enter the slots 78 and 80. The resil-
`iency of the defarmed end section 84 of assembly caver 50 then causes the end section 84 to snap back to
`its original position and ‘surround the camming extensians 73 and 75, lacking the motor and control cirauit as-
`sembly J within the cover, while at the same tine assisting in praperly positianing arid securing the vanaus
`elements of the assembly within the housing,
`Circuit board 3396 (see FIG. 19) defines a substantially enclosed chamber 562 between the circuit board
`and the dottem 162 of the motor housing 50, As best shown in FIGS, 4 and §..aperture 83 on the side of as-
`sembly cover 50 providesaccess, for the detachable edge connector power plug 108,10 the circuit board fraces
`408, 110 and 112, formed as part of the circuit runs‘on baard 336. Input power and grounding conhections ave
`provided to the assembly 1 through power plug 106. A siot 114 extending into the bottom: 102 of housing 50
`limits access to, and cooperates with, the resilient thumb release mechanism 107 of sdgeconnectar lug 106
`fo ensure that the plug oan only be idsertad with proper orientation. Stote 114 also assist in guiding the plug
`io ensure praper connection with and positioning with respect to board 336. The plug 106 is secured in place,
`in proper position, by depressing thumb piece 115 of the mechanism 107 while the plug 106 is being inserted.
`This rotates or pivots the mschanism to mise the cylindrical locking portion 117 until it clears aperture 370 in
`the board 338, whereupon the locking portion may move into, and be scoured wifhin, aperture 37C upon re-
`laase of the thupiece 115.
`Note that the bottom 102 of housing 50 inchides @ circular opening 90 in the central region thereof (ase
`FHSS. 4,5 ard 16-18), and eight radially extending sats 92 extend cutward, awayfrom the center or axis. 437
`of opening 90. This results in aleaved spring configuration molded integrally with the housing 90, thet provides:
`a plurality of resilient tapered fingers 94 formed betwaen each adjacent pair of slats 92. The ends of fingers
`94 are dimensioned and curved to receive, grasp, and position the cylindrical or tubular extension 98 of the
`oi wall caver 818-of the motor, with extension 96 being molded integral with the oil well cover, The extension
`97 is in alignment. with, and opposite, a similar extension 122 (also:-see FIG. 19} on ail well cover &16:through
`which the shaft 18 passes, The extensians $7 and 122 on oppasite ends of the rotor of the motor 16 constitute
`oné.way of mounting the assembly 1 within-a refrigerator, and are positioned within cylindrical openings, or
`bearings (nat shawn}, in a refrigerator to provide | two-point floating support which reduces evaporator fan
`motor vibration and noise within.therefrigerator. This simple yet integral support system enables ready replace-
`mentof existing evaporator fan motors with motors Hluswated herein for repair purpases, or fur inoorperation
`inte existing refrigerator designs,
`The assembly 1 has relatively few parts in order to minimize mamdacturing costs, including the cost af
`materials and assembly, and in order to provide an inherent increase in reliability, The assembly is uncomplex,
`and utilizes rouitifunction structural elements which accurately position, support, and secure the mechanical
`and electronic components in operative relationship relative to each other,
`The housing 50 supports and provides electrical isofation and insulation for elactronic campanernta mount-
`ed on both sides of the printed circuit board 336 (in the iustrated embodiment), These include {see FIG. 3}
`capacitor 361, Hall effect sensor 439 within Hall device holder 338, and other slectronic components such as
`capacitor 367, capacitor 359, and JG 200 pusitianed on one side 340 of the board. Other electranic camponents
`such as powermosfat 560 (see FIG, 19} are positioned onthe opposite side 344 of the board 336 along with
`the printed circuit interconnections or runs 499 {see FIG. 154). The components are slectrcally isolated and
`insulated by being pasiticned in a chamber 562 defined by the board 336 and the bottom 102 of the housing
`50. As will be understood, Jeads suchas lead 342 of metal oxide varistor 3611 (see FIG. 19} extend from the
`electronic companents through the board 338 and are cannected in-circuit with electronic circultry and com-
`ponsais supported on one or the other skies of the board.
`itis to be noted that the.electronic components suct. as the ASIC 200 and the Hall device are pasitioned.
`on beard 336 to one, ora first- side of the large aperture 344 in. the central region of the printed circuit board.
`Fhe rotor $4 of the evaporator fan motor 16. is positioned in the region of, and so that the rator shaft passes
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`20
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`through, aperture 344; while the stater coll §8 and coil bobbin 56 are pasitianed tothe other, or a-sacond, side
`ofthe agerture 344, remote from capacitor 367 and Ralf device holder 338. This general Jayout and structure
`permits 3 two-point floating suspension of the rator about axially extending tubwar portions. or noses.97 and
`122 of the oil well covers. This arrarigement aisc assists in providing a compact, integral assembly whichfis
`within the space available in existing refrigerater designs for existing avaporater fan motors.
`FIGS. 5, 14, 14, 79 and 20 show multifunction parts associated with the Hall sensor 439 for positianing,
`suoporting, and connecting the Hail sensor in an operative interrelationship with bath the motor-and vadous
`coniral cireuit companents.. The Hail device helder 338 is pasitioned on and secured to board 336 (see FIGS.
`& and 20) by means of & pair-of tubular extensions 550 molded integral with the holder 338 and that pass
`through holes in the board. Hall device leads 342 are soldered inio the circuit runs on the bottom or reverse
`side 34+ of board 336 and help providepesitive and-secirepositioning of the Hall device 439, while also es-
`tablishing electrical connections with ather components of the control circuit. As sean in FIG. 5, the shoulder
`364 and extension 356, both molded integral with the holder 938, provide guidance, posiiening or alignment,
`and-suppartfor the stater core 360. of the motor 16. When the stator 52 is assembled with ihe circuit. board
`238, the extension 256 extends into apening 358 in-the stalor care 360 until the shoulder 364 seats against
`the stator core, thus ensuring @ positive and preselected operational magnetic coupling between the Hall sen-
`aor 439, a preselected region the stator core, andthe rotar 54 operationally located in bore 388 of thestatar
`core.
`
`FIGS. 6-8 shaw details of the fabrication, structure and support of rotor 54. The currently preferred method
`of forming the permanent magnét rotor $4 represents a modification of the approaches déseribed in United
`States Patent 5,040,296 issued August 20, 1994 to Willan H. Stark, assigned to the same assignes aa the
`subject patent application, and the entire disclasure of which is-incorporated herein by reference. More spe-
`cifically, wa presently utilize a deep drawn stainless steal cup can’ 302 whioh includes an essentially closed
`end. 306 having a centrally iocaied aperture 364