Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/46—Fastening of windings on the stator or rotor structure
  • H02K3/50—Fastening of winding heads, equalising connectors, or connections thereto
  • H02K3/51—Fastening of winding heads, equalising connectors, or connections thereto applicable to rotors only
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/32—Windings characterised by the shape, form or construction of the insulation
  • H02K3/38—Windings characterised by the shape, form or construction of the insulation around winding heads, equalising connectors, or connections thereto

Definitions

• the invention relates to a rotor provided with at least one ferrule for holding windings and the corresponding electric machine.
• the invention finds a particularly advantageous, but not exclusive, application in the field of starters for a motor vehicle.
• the rotor 1 comprises a collector 2 provided with electrically conductive blades 3, such as copper blades, which extend side by side on its outer periphery.
• the rotor 1 also has longitudinal notches in its body 8 consisting of a bundle of sheets.
• conductors 9 whose ends are welded to a portion of each blade 3 are threaded inside the notches 5.
• the axis of the notches 5 coincides with the axis of the coils.
• blades 3, that is to say that the blades 3 are in front of the notches 5. More specifically, each conductor 9 covered with a layer of enamel 91 for its insulation has two branches connected by a bottom 93 so to form a U.
• the tightening between the hoop 14, 15 and the corresponding bun 12, 13 is between less than 0.15 mm and less than 0.55 mm.
• the tightening of the hoop 14, 15 is such that there is not enough space between two adjacent conductors 9 to allow migration of a varnish 16 during an impregnation operation, as is clearly apparent from the Figures 2a and 2b.
• the vibrations can therefore damage the email layer 91 of the conductors 9, which causes short-circuit problems at the neighboring conductors 9 in contact inside the buns 12 , 13.
• a collector comprising an electrically conductive blade assembly
• a winding formed by a set of conductors inserted at least partly inside the notches and electrically connected to the collector blades, portions of the conductors projecting from radial faces of the axial end of the body of the collector; rotor constituting coils winding,
• hoop mounted axially relative to the body around a bun having an annular wall of axial orientation provided with means for retaining the hoop to axially secure the hoop to the bun and rotated relative to an axis of the hoop.
• the hoop being provided with retaining means, it is possible to reduce the clamping force between the hoop and the buns, or even to mount them with clearance. As a result, the drivers who are less constrained in the buns are spaced apart. others, which optimizes the filling rate of varnish inside buns and thus greatly reduce the risk of short circuit.
• the retaining means of the hoop are intended to impose a shape on a layer of impregnation located on the periphery of the bun such that the hoop is retained by said impregnating varnish layer.
• the impregnating layer is a layer of impregnating varnish on the entire rotor to stiffen said rotor.
• the retaining means comprise at least one hole made in the wall of the hoop for the passage of the impregnation layer so that the impregnating varnish layer has at least one protruding penetrating inside the hole.
• the hole is a through opening.
• the opening has an axis oriented radially relative to the axis of the hoop. This improves the infiltration of the infiltration layer in the opening of the hoop.
• the retaining means comprise a plurality of openings spaced angularly in a regular manner around the wall of the hoop.
• the retaining means comprise at least one protuberance intended to penetrate inside at least one hollow of the impregnating varnish layer.
• the protrusion is either axial and the impregnation layer prevents the rotation of the hoop through this protuberance. This ensures the anti rotation of the hoop relative to the bun even in case of significant centrifugal force.
• the impregnation layer disposed on the bun to stiffen the conductor segments of the bun is disposed before the insertion of the hoop.
• the portions of the conductor segments radially located under the hoop are in contact via the impregnation layer. This avoids that by vibration, the varnish between the portions of the segments of the conductors opposite is removed by sintering and thus avoid electrical contact causing a malfunction of the rotor.
• the hoop and the bun are mounted together with a clearance of between 0.15mm and 0.14mm.
• This positive and negative clearance makes it possible to insert the hoop around the conductor segments forming the bun by hand while ensuring, through the impregnation layer, its role of holding the bun conductor segments against the centrifugal force.
• the hoop has an internal diameter of between 47.55mm and 47.65mm while the bun has an outer diameter of between 47.5mm and 47.8mm.
• the hoop is made of an electrically insulating material.
• the rotor comprises two frets each positioned around a bun.
• two portions of the conductors surrounded by the hoop delimited by the radial plane of the hoop are in contact via an impregnation layer. This prevents the insulators of the portions of conductors from being crumbled by the vibrations.
• the invention also relates to an electric machine characterized in that it comprises a rotor according to the invention.
• Figure 1 already described, shows an overall perspective view of a rotor according to the state of the art
• FIGS. 2a and 2b already described, show sectional views of the conductors in the bunches respectively after the positioning of a holding band around the bun and after the impregnation operation for a rotor according to the state of the art ;
• Figure 3 shows an overall perspective view of a rotor according to the invention;
• Figures 4a and 4b respectively show perspective views and in cross section of a holding band of a bun according to the invention
• Figure 4c shows a sectional view of the retaining band according to the plane B-B of Figure 4b perpendicular to an axis of the hoop;
• Figures 5a and 5b show sectional views of the conductors in the buns respectively after the positioning of a holding band around the bun and after the impregnation operation for a rotor according to the invention
• FIGS 6a and 6b show schematic representations of the bonding zone between the holding ferrule according to the invention and the impregnating varnish layer according to two embodiments of the invention
• Figure 7 shows a schematic representation of the two conductor layers positioned within the notches of the rotor showing the S-shaped notch insulator.
• FIG. 3 shows a rotor 30 comprising a body 31 mounted on a shaft 32 of axis X.
• This body 31 in the form of a bundle of sheets has an outer periphery 31 1 of cylindrical shape delimited axially by two end faces 312, 313 of radial orientation.
• Notches 33 are formed longitudinally at the outer periphery of the body 31.
• a set of conductors 36 are threaded inside each of these notches 33.
• the rotor 30 is provided with a manifold 37 comprising a plurality of contact pieces, here electrically conductive blades 39 to which the ends of the conductors 36 are welded.
• the blades 39 and the conductors 36 are made of copper.
• the blades 39 of the collector 37 are carried by a support 40 of plastics material integral with the shaft 32.
• the support 40 of the collector is, for good temperature resistance, made of thermosetting plastics material, such as a phenolic plastics material thermosetting by example of Bakelite.
• the collet 37 which has blades 39 extending longitudinally side by side on the outer periphery of the support 40 is of the "drum" type.
• the manifold 37 used may be a flat type collector.
• each conductor 36 is here coated with an electrically insulating layer 360, such as enamel, and has two branches 361, 362 connected by a bottom 363 so as to form a U.
• the ends of a conductor 36 welded on the blades 39 are constituted by the free ends of each branch 361, 362.
• the conductors 36 are threaded inside the notches 33 on two distinct layers: the top layer and the layer lower. If one of the branches 361, 362 is positioned in the lower layer then the other branch 361, 362 is in the upper layer and vice versa.
• the cross section of the conductors 36 may be round or square or rectangular.
• the portions of the conductors 36 projecting from the end faces 312, 313 of the body 31 of the rotor 30 form the buns 43, 44 of the coil.
• a notch insulator 46 is positioned around the limbs 361, 362 of the leads.
• this insulator 46 has an S-shaped section.
• This insulator makes it possible not to harm the conductors 36 (coated with the enamel thin layer 360) during their assembly in the bundle of sheets of the rotor 30 equipped with by definition of burrs and fluted for force fitting of the rotor plate package.
• This also electrically insulates the conductors 36 from the grounded package of sheets via the starter housing.
• the clearance between the insulator 46 and the edges of the notches 33 is filled with an impregnating varnish.
• Frets 49, 50 of electrically insulating material visible in Figure 1 are threaded around the buns 43, 44.
• a first band 49 is threaded around the bun 43 located on the side of the collector 37 and formed in particular by the ends of the branches of the conductors 36.
• a second hoop 50 is threaded around the bun 44 located on the opposite side and formed in particular by the funds 363 and a portion of the branches 361 , 362 of the conductors 36 located near the bottoms 363.
• Each band 49, 50 is provided with retaining means 48. of the hoop axially relative to the body 31 and in rotation relative to a Y axis of the hoop 49, 50. This Y axis is substantially coincident with the X axis of the rotor when the hoop 48, 49 is positioned around the bun 43 , 44 of the corresponding winding.
• these frets 49, 50 have an annular wall 51 of axial orientation having an inner periphery 52 intended to be pressed against an outer periphery of the bun 43, 44 corresponding and an outer periphery 53 facing outwardly of the hoop.
• the inner periphery 52 and the outer periphery 53 are connected by edges 54, 55 of axial ends.
• One of the edges 54 is intended to be positioned near one end face 312, 313 of the rotor 30 while the other edge 55 is intended to be positioned axially on the opposite side.
• the retaining means 48 comprise through-openings 63 for the passage of the impregnation varnish formed in the wall 51. These openings 63 have a Z axis radially oriented relative to the Y axis of the wall of the hoop 49, 50.
• the impregnating varnish can penetrate inside the openings 63 acting as a mold to form projections 64 in the varnish layer 68 situated at the outer periphery of the 43, 44.
• These projections 64 have a shape complementary to the openings 63.
• the frets 49, 50 will be retained axially and in rotation by the projections 64 in engagement with the openings 63.
• a varnish is used for example based on heat-resistant epoxy resin which stiffens during its polymerization.
• Other said openings 63 formed in the wall 51 of the hoop 49, 50 act as an axial lock and block in rotation the hoop 49, 50 which are retained by the polymerized impregnating varnish penetrating inside the openings 63.
• each band 49, 50 comprises six openings 63 spaced angularly in a regular manner around the wall 51 of the band 49, 50. There is thus an angular gap A of the order of 60 degrees between two consecutive openings 63 (see Figure 4c).
• the number of openings 63 may vary depending on the application. Alternatively, the openings 63 are not through.
• the openings 63 have a Z axis that is axially oriented with respect to the Y axis of the wall 51, for example taking the form of elongated openings of rectangular shape extending between the edges 54, 55 of the wall annular 51 frets.
• the frets 49, 50 and the buns 43, 44 are mounted between them with a clearance preferably between 0.15 mm and 0.14 mm less.
• Positive play means that the hoop 49, 50 has an internal diameter D1 larger than the external diameter D2 of the corresponding bun 43, 44 (the buns 43 and 44 may have different external diameters D2) while a negative play means that the hoop 49, 50 has an internal diameter D1 smaller than the external diameter D2 of the bun 43, 44 corresponding.
• the hoop 49, 50 has an internal diameter D1 of between 47.55mm and 47.65mm; while the bun has an outer diameter D2 (see Figure 1) between 47.5mm and 47.8mm.
• each band 49, 50 has an internal diameter D1 of the order of 47.6 mm, a width L1 of the order of 5 mm and a thickness L 2 of the order of 1. mm.
• the openings 63 have a diameter L3 of the order of 2.5 mm.
• the retaining means 48 comprise protuberances 69 in place of or in addition to the openings 63.
• protuberances 69 take for example the shape of a cylindrical rod of small dimensions originating from the inner periphery 52 of the wall of the band 49, 50 and directed towards the inside of the band 49, 50.
• the bands 49, 50 will impose on the layer of varnish 68 a shape such that the protuberances 69 will penetrate inside recesses 70 of the lacquer layer 68.
• the frets 49, 50 will be retained axially and in rotation relative to the axis Y by said protuberances 69 in engagement with the recesses 70 after polymerization of the lacquer layer 68.
• the frets 49, 50 are made of an electrically insulating material.
• the frets 49, 50 are advantageously made in one piece, that is to say that there is continuity of material between the different zones of a band 49, 50.
• a third band 75 provides radial retention of the conductors 36 to prevent the effects of the centrifugal force on the solder ends of the conductors 36 between them and on the blades 39 of the manifold 37.
• the rotor 30 may comprise at one end of its shaft 32 a gear wheel 78 located on the opposite side of the collector 37 and intended to form a sun gear in a planetary gear reduction system of a starter, as described for example in the document FR2787833.
• the invention also relates to the electric machine equipped with the rotor 30 described above.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Insulation, Fastening Of Motor, Generator Windings (AREA)
• Manufacture Of Motors, Generators (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 2013
  • 2013-03-14 FR FR1352249A patent/FR3003412B1/fr not_active Expired - Fee Related
• 2014
  • 2014-03-12 WO PCT/FR2014/050557 patent/WO2014140477A1/fr active Application Filing
  • 2014-03-12 CN CN201480012630.9A patent/CN105009423B/zh not_active Expired - Fee Related
  • 2014-03-12 US US14/773,559 patent/US20160020661A1/en not_active Abandoned
  • 2014-03-12 EP EP14713555.2A patent/EP2973952A1/de not_active Withdrawn

Non-Patent Citations (2)

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