EP0304343A2 - Paquet de tôles et procédé pour former des projections et des dépressions - Google Patents

Paquet de tôles et procédé pour former des projections et des dépressions Download PDF

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Publication number
EP0304343A2
EP0304343A2 EP88309499A EP88309499A EP0304343A2 EP 0304343 A2 EP0304343 A2 EP 0304343A2 EP 88309499 A EP88309499 A EP 88309499A EP 88309499 A EP88309499 A EP 88309499A EP 0304343 A2 EP0304343 A2 EP 0304343A2
Authority
EP
European Patent Office
Prior art keywords
lamination
projection
depression
pack
laminations
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP88309499A
Other languages
German (de)
English (en)
Other versions
EP0304343A3 (fr
Inventor
William George French
Charles Harold Webb
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linton and Hirst Ltd
Original Assignee
Linton and Hirst Ltd
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 Linton and Hirst Ltd filed Critical Linton and Hirst Ltd
Publication of EP0304343A2 publication Critical patent/EP0304343A2/fr
Publication of EP0304343A3 publication Critical patent/EP0304343A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D35/00—Combined processes according to or processes combined with methods covered by groups B21D1/00 - B21D31/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0233—Manufacturing of magnetic circuits made from sheets

Definitions

  • the present invention in one aspect relates to: a pack of laminations for an electromagnetic device; a lamination for use in the pack; a method of making such a pack; apparatus for making the pack; and an electromagnetic device comprising the pack.
  • the present invention in another aspect relates to forming projections and depressions.
  • each lamination is rigidly connected to its adjacent lamination by a plurality of connections.
  • Each connection disrupts the flux paths.
  • air gaps are invariably present between the pole core faces defined by the packs. Because of the disruption of the flux paths and the presence of the air gaps, there are problems in meeting electromagnetic specifications for devices.
  • One previously proposed solution to that problem is to use higher quality material but that increases the cost.
  • Another previously proposed solution is to use unconnected plates or laminations but that increases the cost due to the need for expensive assembly equipment.
  • a pack or stack of connected laminations which pack is torsionally flexible.
  • each lamination is connected to an adjacent lamination by a single connection.
  • a method of forming a projection and/or depression in a sheet of ductile material comprising applying a punch to the material to extrude the projection past the lip of, and into, a projection forming die, the lip being radiussed or conical.
  • the height of the projection and/or the depth of the depression so produced is about 65 % to about 70 % of the material thickness.
  • the projection and/or depression made by the method of the said another aspect is used in embodiments of the said one aspect. It may however be used in other situations to connect laminations.
  • the electromagnetic device is e.g. a choke assembly which comprises two packs of "E-shaped" laminations each pack comprising laminations 5 stacked on partitioning plates 6.
  • the faces of the limbs of the "E-shaped” laminations define pole faces 7.
  • the two packs are placed with their pole faces abutting.
  • the central limbs of the laminations are spaced apart by an air gap 8 of predetermined width.
  • An induction coil 9 produces magnetic flux 10 in the laminations.
  • each lamination in each pack, is connected to its adjacent lamination by only a single connection producing a torsionally flexible pack.
  • the torsional flexibility allows at least the reduction if not the elimination of unwanted air gaps between the pole faces 7.
  • the reduction of the number of connections between laminations reduces the disruption of the flux paths.
  • the result is increased electrical efficiency as compared with packs of laminations which are made of the same quality of material but with laminations rigidly connected by a plurality of connections.
  • the electrical efficiency is comparable with that obtained by the use of loose (unconnected) plates but at less cost.
  • each lamination comprises a single depression 3 and a single projection 4 aligned on a common axis perpendicular to the lamination.
  • the projection of one lamination projects into the depression of its adjacent lamination.
  • a pack of such laminations 5 is built up on a lamination 6 referred to herein as a partitioning plate 6 which comprises a through-hole 2 in place of the depression 3/projection 4 combination.
  • the projection 4 of the bottom most lamination 5 projects into the hole 2.
  • the pack of laminations in accordance with an embodiment of said one aspect of the present invention, in which the laminations are connected one to another by only the single projection/depression, must withstand the stresses applied by subsequent production processes, including high temperature heat treatment, and also radial movement to provide the packs with the torsional flexibility which allows the magnetic pole faces 7 to butt together without air gaps throughout the pack length thus maintaining the predetermined air gap 8 (when applicable).
  • the depressions and projections of the laminations have the form shown in Figs. 3 and 4.
  • the depression 3 in each lamination has a depth P of about 69% of the thickness T of the material of the lamination.
  • the lip of the depression 3 is radiussed with a radius R.
  • the depression is circularly cylindrical.
  • the internal diameter of the depression is less than the diameter of the corresponding projection to produce an interference fit.
  • the projection 4 which is circularly cylindrical, has a height H which is about 65% of the material thickness T.
  • the base of the projection 4 is either:
  • the cone C1 or radius r1 does not foul the radius R at the lip of the depression thus allowing total engagement of the projection 4 into the depression 3 to prevent air gaps resulting between the faces of the laminations in the pack.
  • the hole 2 in the partitioning plate 6 has the same form as the depression 3 in the laminations except, of course, that it extends all the way through the plate 6.
  • the projection 4 of the bottom most lamination 5 fits with the partitioning plate in the same way as it would fit with a depression 3 in a lamination.
  • the depression 3 and projection 4 in each lamination are produced by way of example in the following manner, in accordance with another aspect of the present invention.
  • Metal strip 1 is located and gripped tight in a manner to be described hereinafter over a die 14.
  • the die defines a right circularly cylindrical opening the lip of which is either:
  • a depression form punch 13 simultaneously forms the depression 3 and causes the metal of the strip 1 to be extruded into the projection form die 14 past the cone C or radius r.
  • the normal shear stress fracture condition at about 50% of the metal thickness T is significantly changed, due to presence of the radius r or cone C at the lip of the die 14, to produce the depression depth P at 69% of the metal thickness T and the corresponding projection height at 65% of the thickness T without fracturing.
  • the 4% difference between depression depth P and projection height H represents the compression and thinning of the metal during the action of being forced past the cone C or radius into the projection form die 14 providing a burnished finish to the projection circumference.
  • the internal diameter of the projection form die 14 is made 0.022mm larger than the outside diameter of the depression form punch 14.
  • the action of extruding the metal into the projection form die 14 past the cone C or radius r ensures that the depression diameter is produced 0.004mm smaller than the diameter of the depression punch 13. This produces an interference of 0.026mm between the fit of the projection 4 into the depression 3.
  • the cone C or radius r applied to the lip of the projection form die 14 produces a similar size cone C1 or radius r1 at the base of the projection 4.
  • the resultant cone C1 or radius r1 produced at the base of the projection 4 is smaller than the radius R produced at the opening of the depression 3, thus allowing full engagement of the projection 4 into depression 3 ensuring no gaps exist between the metal plates to provide a single connecting feature that can withstand the stresses previously shared by multi-connecting features.
  • the maximum flatness deviation B (see e.g. Fig. 3) at the base of the depression 3 and the maximum flatness deviation B1 at the top of the projection 4 is 0.008mm.
  • the decision to use a cone C or radius r at the lip of the projection form die 14 mainly depends on the ductility of the metal of the strip 1. High ductility material will give similar percentages to those stated when either a cone C or a radius r is used. Low to medium ductility material requires a low angle cone C to give similar percentages to those stated.
  • a spring loaded stripper pad 18 is used.
  • the pad 18 may be aided by the use of a spring loaded ejector 18a which projects through the bore in the projection forming die 14.
  • the ejector 18a would be used especially when a thin metal strip 1 is used in order to prevent distortion of the laminations.
  • the ejector 18a would be used when the thickness T of the metal strip 1 is less than 0.21mm. The presence of the ejector 18a makes no substantial difference to the maximum flatness deviation B mentioned hereinabove.
  • the hole 2 in the partitioning plate 6 is made using a hole piercing punch of the same dimensions as the depression form punch 13 and the form and dimensions of the hole 2 are the same as the form and dimensions of the depression 3 except that its depth is equal to the thickness of the material.
  • the projection 4 of the bottom most lamination 5 fits with the hole 2 in exactly the same manner as it would fit with a depression 3.
  • FIG. 8 shows, by way of example, the production of partitioning plates and laminations for use in a pack as shown in Fig. 1. In such a pack the single connection feature on each lamination is at the centre of the lamination.
  • locating holes 19′ displaced from the centre of the metal strip 1 are punched. These holes are used as described hereinafter for accurately locating the metal strip over the die 14.
  • the hole 2 of the partitioning plate is also punched out at stage 1.
  • Stage 2 is a idle station.
  • Stage 3 the depression 3 and projection 4 are produced.
  • Stage 4 is an idle station.
  • the E-shaped lamination is stamped out of the strip.
  • Figs. 8A to 8C are carried out using a single multi-stage progression tool as schematically illustrated in Figs. 9A to 9D.
  • the tool comprises a male punch assembly 26 and female die assembly 27 secured in an automatic power press.
  • the metal strip 1 is gripped tightly between a die plate 22 and stripper plate 21.
  • the locating holes 19′ are produced by means not shown in Fig. 9A.
  • the holes 2 for the partitioning plates are stamped out of the metal strip 1 by a punch 11 which cooperates with a die 12 best shown in Fig. 9B.
  • the die II is actuated when required to punch the holes by a cam 20 operated by an electro-preumatic arrangement (not shown).
  • Stage 2 is an idle stage.
  • Stages 3 and 4 require to be considered together.
  • the locating holes 19′ pass through stages 1, 2 and 3 into stage 4.
  • pilots 19 are inserted through the locating holes 19′ to accurately locate the metal strip 1 which is also gripped tightly between the stripper plate 21 and die plate 22.
  • the die form punch forms the depression 3 and causes the metal of the strip 1 to be extruded past the cone C1 or radius r of the projection forming die 14 to form the depresssion 3 and projection 4.
  • the stripper pad 18, and, if provided, the ejector 18a operate to eject the projection from the die 14.
  • the stripper pad 18 is biassed by a spring 18b and the ejector 18a is biassed by a spring 18c.
  • the laminations 5 are stamped out of the strip 1 by a punch 15 which cooperates with a die 16 as best shown in Fig. 9D.
  • the laminations 5 are stacked one upon the other with the projection of each lamination projecting into the corresponding depression of the adjacent lamination.
  • a thrust rod 17 through the punch 15.
  • the thrust rod 17 engages with the depression on the punched out lamination.
  • the interference fit of the projections 4 into the depressions 3 necessitates the pressure applied by the punch 15 and the thrust rod 17 being countered by a similar counter pressure.
  • the counter pressure is progressively developed by the die 16 followed by segmented restriction blocks 23 and 24 and concluded by the adjustable pressure of a restrictor tube 25.
  • the restriction blocks 23 and 24 comprise apertures that are slightly smaller than the laminations and partitioning plates 6. This restricts the free passage of the pack.
  • the aperture of block 24 is slightly smaller than that of block 23 to progressively develop the counter pressure.
  • the tube 25 comprises two precision ground halves 25′ and 25 ⁇ which are spaced apart transversely of the tube 25 and urged towards each other to reduce the gap between them. The tube halves are urged towards each other by spring pressure developed by e.g. sets of disc washers (Belleville Washers) 28.
  • the laminations 5 are stacked up on a partitioning plate 6 as shown in Fig. 9D.
  • the conical or radiussed lip of the die 14 is easily redressed during tool service with a low cost fixture incorporating the appropriate redressing wheel.
  • the pack of laminations which is torsionally flexible with the laminations connected one to another by a single connecting feature, as described above, provides an electromagnetic device of improved electrical efficiency because of the reduction of connecting features. Furthermore, the use of a single connecting feature minimises the uninsulated contact area between neigbouring magnetic pole core plates thus proportionally reducing the potential problem of eddy currents developing between the pole core plates.
  • the torsional flexibility of the pack allows the pole faces of coupled pole core packs to butt together throughout the length of the pack, thus avoiding air gaps which can occur with rigid multi-connected packs. That minimises the disruption of the magnetic flux paths to allow improve electrical efficiency.
  • the pack of laminations according to embodiment of the invention offers reduced costs for providing comparable electrical efficiency as compared with rigid packs or packs made using loose plates. The reduced cost results from the avoidance of the need for higher quality electrical steel in the case of rigid packs or from the avoidance of the use of more expensive assembly equipment in the case of packs made of loose plates.
  • lamination packs made in accordance with embodiments of the invention are useful in many types of electro magnetic device and may be used for stators, chokes, transformers etc.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Punching Or Piercing (AREA)
EP88309499A 1987-06-22 1988-10-11 Paquet de tôles et procédé pour former des projections et des dépressions Withdrawn EP0304343A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8714581A GB2206453B (en) 1987-06-22 1987-06-22 Pack of laminations and forming projections and depressions

Publications (2)

Publication Number Publication Date
EP0304343A2 true EP0304343A2 (fr) 1989-02-22
EP0304343A3 EP0304343A3 (fr) 1989-11-08

Family

ID=10619338

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88309499A Withdrawn EP0304343A3 (fr) 1987-06-22 1988-10-11 Paquet de tôles et procédé pour former des projections et des dépressions

Country Status (4)

Country Link
EP (1) EP0304343A3 (fr)
GB (1) GB2206453B (fr)
HK (1) HK82592A (fr)
SG (1) SG36392G (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2655472A1 (fr) * 1989-12-05 1991-06-07 Merlin Gerin Circuit magnetique a bague de dephasage pour appareillage electrique a courant alternatif.
WO1999016092A1 (fr) * 1997-09-19 1999-04-01 Vacuumschmelze Gmbh Procede et dispositif de fabrication de paquets formes de lames de toles pour noyaux magnetiques
DE102009051271A1 (de) * 2009-10-29 2011-05-19 Eaton Industries Gmbh Montagehilfe zum Stanzpaketieren

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2206453B (en) * 1987-06-22 1992-01-02 Linton & Hirst Ltd Pack of laminations and forming projections and depressions
US5809638A (en) 1992-10-26 1998-09-22 L.H. Carbide Corporation Method for manufacturing laminated parts with center interlock
US5799387A (en) * 1996-06-05 1998-09-01 L.H. Carbide Corpordation Lamina stack having a plurality of outer perimeter configurations and an apparatus and method for manufacturing said stack
US5755023A (en) * 1996-06-05 1998-05-26 L.H. Carbide Corporation Lamina stack with at least one lamina layer having a plurality of discrete segments and an apparatus and method for manufacturing said stack
US6636137B1 (en) 1996-06-05 2003-10-21 L.H. Carbide Corporation Ignition coil assembly
US6163949A (en) * 1996-06-05 2000-12-26 L.H. Carbide Corporation Method for manufacturing long, slender lamina stack from nonuniform laminae
US6195875B1 (en) 1996-06-05 2001-03-06 L.H. Carbide Corporation Apparatus for manufacturing long, slender lamina stacks from nonuniform laminae

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GB233179A (en) * 1924-06-18 1925-05-07 David Albert Victor Rist An improved method of and means for manufacturing embossed or intaglio name and number plates
GB493367A (en) * 1936-04-06 1938-10-06 Meyer Kauffman Improvements in or relating to methods of and apparatus for embossing
GB762040A (en) * 1954-07-07 1956-11-21 Birmetals Ltd Improvements in or relating to tread surfaces on extruded metal sections
GB857915A (en) * 1958-03-12 1961-01-04 Gen Electric Co Ltd Improvements in or relating to laminated electromagnetic cores
GB928880A (en) * 1961-04-24 1963-06-19 Walter Kohlhagen Improvements in or relating to bearings
US3152498A (en) * 1961-08-31 1964-10-13 Westinghouse Electric Corp Cores
CH482278A (de) * 1967-11-14 1969-11-30 Leuenberger H Drossel oder Transformator
CH484501A (de) * 1967-12-29 1970-01-15 Leuenberger H Verfahren zur Herstellung eines Blechpaketes
NL7401806A (nl) * 1974-02-09 1975-08-12 Philips Nv Induktieve stabilisatie-ballast voor een gas- dampontladingslamp.
GB2050904A (en) * 1979-06-20 1981-01-14 Tate Architectural Products Rigid stiffening web for load- bearing panel
GB2104430B (en) * 1981-08-24 1985-05-09 Gillette Co Securing a razor blade to a support
DE8208150U1 (de) * 1982-03-23 1983-09-01 Robert Bosch Gmbh, 7000 Stuttgart Elektrische wicklung mit einem eisenkern aus geschichteten blechlamellen
EP0133858B1 (fr) * 1983-08-12 1986-09-10 Essa Fabrique de Machines S.A. Procédé et dispositif pour fabriquer des paquets composés de lames de tôle pour des noyaux magnétiques de machines électriques
US4586236A (en) * 1984-01-17 1986-05-06 Penn United Technology, Inc. Method and apparatus for forming stacks of laminated metallic members
GB8528063D0 (en) * 1985-11-14 1985-12-18 Telcon Metals Ltd Magnetic core
DE3605355A1 (de) * 1986-02-20 1987-08-27 Skf Gmbh Verfahren zum einstellen von maschinenteilen
GB2206453B (en) * 1987-06-22 1992-01-02 Linton & Hirst Ltd Pack of laminations and forming projections and depressions

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2655472A1 (fr) * 1989-12-05 1991-06-07 Merlin Gerin Circuit magnetique a bague de dephasage pour appareillage electrique a courant alternatif.
EP0432055A1 (fr) * 1989-12-05 1991-06-12 Merlin Gerin Circuit magnétique à bague de dÀ©phasage pour appareillage électrique à courant alternatif
WO1999016092A1 (fr) * 1997-09-19 1999-04-01 Vacuumschmelze Gmbh Procede et dispositif de fabrication de paquets formes de lames de toles pour noyaux magnetiques
US6588093B1 (en) 1997-09-19 2003-07-08 Vacuumschmelze Gmbh Method and device for producing bundles of sheet metal laminates for magnetic cores
DE102009051271A1 (de) * 2009-10-29 2011-05-19 Eaton Industries Gmbh Montagehilfe zum Stanzpaketieren

Also Published As

Publication number Publication date
GB2206453B (en) 1992-01-02
EP0304343A3 (fr) 1989-11-08
GB2206453A (en) 1989-01-05
SG36392G (en) 1992-06-12
HK82592A (en) 1992-11-06
GB8714581D0 (en) 1987-07-29

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