Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1998-06-24
1999-10-26
Ramirez, Nestor
Electrical generator or motor structure
Dynamoelectric
Rotary
310 67R, 2642722, 29596, H02K 104
Patent
active
059734248
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
The invention relates to a method or insulating the stator of an electronically commutated direct current motor, an apparatus for carrying out such a method, and a stator that is manufactured in accordance with this method.
In electric motors that are used in so-called clean rooms, or in a humid or aggressive environment, it is necessary to provide the sensitive parts of the motor, such as the winding and the printed circuit board, with a protective coating. It is therefore known, e.g. from DE 37 37 050 A1, ELASSER/PAPst, published, May 5, 1988, to cast artificial resin around the stator of an electric motor. The object in the present disclosure lies essentially in simplifying the production of the bond or connection between the stator winding and the printed circuit board.
Carrying out a powder coating is also known. The known methods not only require mechanical finishing, but are also not in a position to fulfill the requirements of higher insulation classes (e.g. protection type DIN/VDE 0470 IP-54) German Industrail Norm
SUMMARY OF THE INVENTION
The object of the invention is to provide a method for insulating stators, which fulfills even extreme insulation and protection requirements for electric motors.
This object is achieved according to the invention by placing the stator and an associated circuit in an injection-molding die having laterally movable jaws, closing the movable jaws to define a chamber having walls closely surrounding the stator and circuit, injecting a liquid hot thermoplastic into the chamber to thereby form a thin coating over the stator and circuit, pausing until the thermoplastic has solidified, and retracting the movable jaws and removing the thus-insulated stator and circuit.
FIG. 1 depicts a section through an injection molding tool (schematically);
FIG. 2 is a section along the line II--II in FIG. 1;
FIG. 3 is a section through a stator, without insulating coating, of a fan, along the line III--III in FIG. 4;
FIG. 4 is a bottom view of a stator according to FIG. 3;
FIG. 5 is a section through a stator according to the invention, with an insulating coating;
FIG. 6 is a section through a stator, with an insulating coating, which is mounted in a fan.
DETAILED DESCRIPTION
In FIG. 1, an injection molding die 20, for manufacturing a stator 1 according to the invention, is schematically represented in a sectional view. In this instance, the injection molding form comprises for example, three laterally retractable jaws 21 (FIG. 2) that are disposed around the lamination bundle 2 of the stator 1. A supply line 22, for injecting the plastic, is disposed between two of the jaws 21. The centering of the stator 1 is carried out on one end by a centering mandrel 23, which protrudes conically or in a true-to-fit manner into the bearing seat 3 of a bearing support tube 4 (FIGS. 3, 5, 6), and it is axially fixed or immobilized on the other end by a ram 24. As a result, during the injection molding process, plastic is prevented from penetrating into the bearing support tube 4. The injection of the thermoplastic hot-melt adhesive used here takes place at approximately 200.degree. C.
The jaws 21 rest with axial pressure against a flange 5 and thus produce a seal. An additional sealing is obtained by means of the ram 24, which together with the closed jaws 21, defines a hollow space. Thereby, one achieves the result that no hot-melt adhesive is injected outside this flange 5.
In a recess, a receptacle portion 25 of the injection molding die 20 contains the centering mandrel 23, conical faces 26, 27 which serve to guide the jaws 21, and a floor 28. Slots, not shown, permit the insertion of ribs 7 (FIG. 4) of a fan housing 6 into the receptacle part 25. The fan housing 6, shown in FIGS. 3-4 and 6 by way of example, comprises a bearing support tube 4 and a flange 5, and is integrally formed as a single plastic part.
After insertion of the stator 1, which rests on the floor 28 of the recess of the receptacle portion 25, the jaws 21 and the ram 24 are moved up to a stop, and define a
REFERENCES:
patent: 4922604 (1990-05-01), Marshall et al.
patent: 5552650 (1996-09-01), Cap et al.
patent: 5806169 (1998-09-01), Trago et al.
Henkel Corp. Chemicals Group, kankakee, IL, Macromelt 6797 (Dimer Acid Based Polyamide Resin) Material Safety Data Sheet # 4611, revised Mar. 26, 1998.
Derwent WPI abstract of De 37 37 050-A1, Elasser/Papst, publ. May 5, 1988.
Patent Abstracts of Japan, vol. 18, No. 167 (E-1528), re Furukawa/Fuji Electric, Dec. 17, 1993.
Derwent WPI Abstract of JP 5-336 722-A, Fuji Electric application filed Dec. 17, 1993.
Patent Abstracts of Japan, vol. 95, No. 6, re Doi/Matsushita, Mar. 17, 1995.
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Derwent WPI abstract of WO 96-31936, Byrnes-Neal-Trago/DuPont, publ. Oct. 10, 1996.
Satz-Rechen-Zentrum (SRZ)-Berlin flyer re DIN (German Industrial Standards) available on CD-ROM.
Deutsches Institut fur Normung e.V. (German Institute of Standards) & Verband Deutsche Elektrotechniker (VDE) e.V. (Federation of German Electrical Engineers), German Industrial Norm DIN/VDE 0470 IP-54 (corresponding to European Norm EN 60 529), Cover page & pp. 5-7 (.COPYRGT.Nov. 1992).
Engelberger Reimund
Kieninger Jurgen
Ghahramawi Saeed
Oliver Milton
Papst-Motoren GmbH & Co. KG
Ramirez Nestor
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