WO2014189382A1 - Procédé d'encapsulation de stator de machine électrique - Google Patents

Procédé d'encapsulation de stator de machine électrique Download PDF

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Publication number
WO2014189382A1
WO2014189382A1 PCT/NO2014/050078 NO2014050078W WO2014189382A1 WO 2014189382 A1 WO2014189382 A1 WO 2014189382A1 NO 2014050078 W NO2014050078 W NO 2014050078W WO 2014189382 A1 WO2014189382 A1 WO 2014189382A1
Authority
WO
WIPO (PCT)
Prior art keywords
stator
ironless
spacers
encapsulation
resin
Prior art date
Application number
PCT/NO2014/050078
Other languages
English (en)
Inventor
Jörg HÖYLAND
Lasse FORFOT
Nils Börge NODDELAND
Stig Ove Stornes
Rune Morten Haug
Original Assignee
Smartmotor As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Smartmotor As filed Critical Smartmotor As
Publication of WO2014189382A1 publication Critical patent/WO2014189382A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/12—Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/08—Insulating casings

Definitions

  • the invention relates to a method of encapsulation of a stator of an electrical machine according to the preamble of claim 1.
  • the invention especially relates to a method for avoiding air trapping during the casting process and preventing cracking and debonding of the casting resin, thus ensuring reliable and stable curing and improving quality of production of the encapsulated stator, resulting in higher reliability and longer lifetime of the electrical machine.
  • US 2006250037 describes an encapsulation process of active parts of stator where a supportive ring is used to protect the active parts from air gap side and resin is used only for ends of the active parts.
  • a problem of such an approach can be air trapping during filling of the end area with the encapsulant.
  • Another drawback is that the considerable thickness of the ring results in a relatively large "magnetic" gap between stator and rotor which is degrading the machine characteristics.
  • US 2,749,456 describes an encapsulation process of the active parts of stator without the use of a supportive ring, and where encapsulant covers ends of the active parts and slot openings at the air gap side. Periphery of the laminated stack is not covered by encapsulant, but is instead covered by a metal tube.
  • the advantage of this approach is that the "magnetic" gap between stator and rotor is small, resulting in improved machine characteristics.
  • the drawback of this approach is that tips of stator laminations are unprotected. Also the problems of air trapping can take place when pushing the encapsulant into voids inside the stator.
  • NO 331710 Bl it is described a solution where casting resin covers active parts from all sides.
  • the electrical machine in NO331710 Bl does not have stator housing. This approach works well for small ring-shaped machines with diameters below approximately 1 meter. For machines with larger diameters it is not applicable due to first of all complexity of the mold and the problem of air trapping, cracking of the encapsulant and debonding.
  • a perspective solution of encapsulation of stators of large machines includes use of a metal housing of tubular (cylindrical) shape holding the active parts (laminated core and windings) and applying protective layers both at the ends of the active parts and at the air gap side, i.e. in stator bore.
  • protective layers completely cover the active parts from all sides except for the periphery where the metal housing is arranged.
  • the cracks are created mainly due to shrinkage of the encapsulant during curing and contact of the shrinking encapsulant with the sharp corners of the laminated stator core.
  • Shrinkage of the resin during casting process can be in the order of 1-4 %, which is considerable.
  • the width of the resin along the active part of the machine at stator inner diameter is typically in few millimeters (in many cases 3-6 mm) so shrinkage during curing will not give that much problem.
  • the resin thickness is typically above 10 mm so shrinkage in this region can result in cracks, first of all at sharp edges of the laminated stator core.
  • Air trapping can probably be prevented by rotating the whole mold and stator during filling it up with encapsulant, but this would make the process too complex and the set-up too expensive.
  • the main object of the present invention is to provide a method improving the encapsulation process of a stator in electrical machines by solving the above mentioned problems.
  • Another object of the present invention is to provide a method of encapsulation of stator of an electrical machine which avoids debonding between the casting resin and stator.
  • the present invention is intended to solve the problems described above by introducing special-purpose elements in end-winding area of a stator of an electrical machine prior to encapsulation of active parts and parts of stator housing with a casting resin.
  • the special-purpose elements are arranged for serving one or more of the following purposes:
  • the method includes arranging elements in the form of ironless spacers in an end-winding area prior to encapsulation of active parts and parts of stator housing with a casting resin.
  • the ironless spacers are adapted to be attached to stator laminations under the end- windings and exhibit a special shape, i.e. preferably exhibit an axial cross-section which is close to triangular or trapezoidal.
  • the ironless spacers are arranged to prevent air entrapment during the casting process by providing a decline angle from outer diameter to inner diameter of active parts of the stator. Additionally, the ironless spacers are preferably further provided with smooth round corners at air gap side to help avoiding cracks in the casting resin during the curing process.
  • stator laminations are covered by ironless spacers, cracks in the casting resin during the curing process are avoided when subjected to thermal loads. Additionally, the ironless spacers are arranged to occupy space, thus reducing amount of the casting resin, consequently reducing its shrinkage, and thereby preventing cracks.
  • a second embodiment of the method includes arranging elements in the form of pre- casted resin blocks in an end-winding area prior to encapsulation of active parts and parts of stator housing with a casting resin.
  • the pre-casted resin blocks are arranged to occupy space and thus reduce the amount of the casting resin and consequently reducing its shrinkage and preventing cracks.
  • a third embodiment of the method includes arranging elements in the form of a plate provided with teeth or profiles along its length in an end-winding area prior to encapsulation of active parts and parts of stator housing with a casting resin.
  • the plate provided with teeth or profiles along its length is arranged to a stator housing surface by means of e.g. gluing or similar fastening methods.
  • the method according to the present invention accordingly enables a simple casting process of the stator and produces more reliable encapsulation.
  • the method according to the present invention includes the arrangement of special- purpose elements in the end-winding area of a stator prior to encapsulation with a casting resin. By this air trapping, cracks and debonding between the stator housing and resin is prevented.
  • Another advantage with the method according to the present invention is that the needed amount of resin volume at the end-windings is reduced and thereby stress caused by the resin shrinking during cure is limited.
  • a glass-fiber mesh can be arranged in stator bore prior to encapsulation.
  • FIG. 1 is a perspective view of stator end portion provided with elements according to a first embodiment of the present invention
  • FIG. 2 is a cross-sectional view illustrating details of a stator of half of an electrical machine
  • FIG. 3 is a closed view of round corner of the elements according to the first embodiment of the present invention to avoid sharpness of stator laminations edges
  • FIG. 4 is a perspective view of stator end portion provided with elements according to a second embodiment of the present invention attached to the stator housing,
  • FIG. 5 illustrates the effect of a resin ring contracting inwards and leading to debonding of resin from the stator housing by peeling off
  • FIG. 6 shows elements of a third embodiment according to the invention arranged to the stator surface.
  • FIG. 1 is a perspective view of end portion of a stator 10, containing stator lamination stack 11, end-winding 12 and a set of elements 13 according to a first embodiment of the present invention.
  • the elements 13 according to the first embodiment are in the form of ironless spacer and these are attached to the end of the stator laminations stack 11 by suitable means.
  • the ironless spacers 13 have a special shape exhibiting a declining angle from outer diameter (stator housing 18 side) to inner diameter (air gap side).
  • the ironless spacers 13 preferably have a triangular or trapezoidal shape (seen in cross-section), but can have any similar shapes for the purpose of avoiding air trapping.
  • the ironless spacers 13 can form a ring, consisting of many element segments. The ring accordingly exhibits a variable cross-section.
  • the ironless spacers 13 are preferably of non-magnetic and non-conductive material.
  • the ironless spacers 13 can preferably further be made of the same material as a casting resin 15 or made of materials compatible with the casting resin 15 or made of glass fiber.
  • FIG. 2 illustrating a cross-sectional view of a stator 10 of half of the electrical machine.
  • the details of rotor 14 of the electrical machine are not in the scope of this invention and will not be described further.
  • By means of arrangement of these specially shaped ironless spacers 13 risks of air trapping and cracking are avoided, and provides a more reliable and simple casting process with a given encapsulation material 15.
  • the ironless spacers 13 are preferably provided with round corners for avoiding sharpness of edges of stator lamination stack 11.
  • shrinkage of the casting resin 15 is higher at end portions of the stator 10 compared to the air gap area.
  • FIG. 4 illustrates a perspective view of end portion of the stator 10.
  • the shrinkage of the casting resin 15 in end portion 16 of stator 10 can be avoided by introduction of elements 17 according to a second embodiment of the present invention in the form of pre-molded resin blocks.
  • These resin blocks 17 are attached to a stator housing 18 and reduce the effective end portion area 16 and thus reduce the stresses developed in the curing process and reduced problems developed due to shrinkage.
  • the resin blocks 17 are e.g. screwed to an end flange of the stator 10, but could also be held in place in other ways.
  • the resin blocks 17 can be made of the same material as the encapsulating resin 15 that will be used or a material being compatible with the casting resin 15.
  • These resin blocks 17 are also to reduce the volume of resin 15 that is needed to fill the area between end- windings 12 and the end flange. If this would not have been done, there is a risk of having large shrinking forces between the resin 15 and stator housing 18/flange. Since they are made of the same resin or compatible resin, one will get a good adhesion to the casting resin 15.
  • FIG. 5 illustrates the effect of a resin ring 19 contracting inwards and leading to debonding of resin 15 from the stator housing 18 by peeling off. If there is a location with lesser adhesive properties, a crack might be initiated here and will progress around the stator housing 18. Since the stator housing 18 is a smooth surface, there is nothing to stop the progression of the debonding.
  • elements 20 according to a third embodiment according to the present invention in the form of bonding a plate 20 to the stator surface, which plate 20 is provided with teeth or profiles 21 along its length, as shown in Figure 6.
  • the plate 20 and teeth or profiles 21 are preferably made of the same material as the casting resin 15, a material compatible with the casting resin 15 or glass fiber.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Manufacture Of Motors, Generators (AREA)

Abstract

La présente invention concerne un procédé d'encapsulation de stator (10) d'une machine électrique, grâce à l'encapsulation des parties actives et des parties d'un boîtier de stator (18) avec une résine de coulée (15), qui comprend l'agencement d'au moins un des éléments suivants : des entretoises exemptes de fer (13), des blocs de résine pré-moulés (17), et/ou de plaques (20) avec des dents ou profilés (21), dans une zone (16) d'enroulement d'extrémité (12) du stator (10) préalablement à l'encapsulation des parties actives et des parties du boîtier de stator (18) avec la résine de coulée (15).
PCT/NO2014/050078 2013-05-24 2014-05-19 Procédé d'encapsulation de stator de machine électrique WO2014189382A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20130729A NO335654B1 (no) 2013-05-24 2013-05-24 Fremgangsmåte for innkapsling av stator for elektrisk maskin
NO20130729 2013-05-24

Publications (1)

Publication Number Publication Date
WO2014189382A1 true WO2014189382A1 (fr) 2014-11-27

Family

ID=51933836

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2014/050078 WO2014189382A1 (fr) 2013-05-24 2014-05-19 Procédé d'encapsulation de stator de machine électrique

Country Status (2)

Country Link
NO (1) NO335654B1 (fr)
WO (1) WO2014189382A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021122453A1 (de) 2021-08-31 2023-03-02 Elaphe Propulsion Technologies, Ltd. Stator mit permanenter Schutzbarriereabdichtung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080238226A1 (en) * 2007-03-30 2008-10-02 Kabushiki Kaisha Yaskawa Denki Stator and gap winding motor using the same
EP2525475A1 (fr) * 2010-05-26 2012-11-21 Toyota Jidosha Kabushiki Kaisha Structure de stator et procédé de fabrication d'un stator

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004054308B3 (de) * 2004-11-09 2006-07-27 Franklin Electric Europa Gmbh Abstandshülse und Elektromotor mit einer Abstandshülse

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080238226A1 (en) * 2007-03-30 2008-10-02 Kabushiki Kaisha Yaskawa Denki Stator and gap winding motor using the same
EP2525475A1 (fr) * 2010-05-26 2012-11-21 Toyota Jidosha Kabushiki Kaisha Structure de stator et procédé de fabrication d'un stator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021122453A1 (de) 2021-08-31 2023-03-02 Elaphe Propulsion Technologies, Ltd. Stator mit permanenter Schutzbarriereabdichtung

Also Published As

Publication number Publication date
NO20130729A1 (no) 2014-11-25
NO335654B1 (no) 2015-01-19

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