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EP-4736298-A1 - ELECTRIC MOTOR WITH IMPROVED ASSEMBLY

EP4736298A1EP 4736298 A1EP4736298 A1EP 4736298A1EP-4736298-A1

Abstract

The invention relates to an electric motor including a stator comprising a plurality of radial teeth which are made up of bundles of ferromagnetic laminations and overmoulded to form an overmoulded stator support, the stator support having, between each tooth, a notch designed to receive the wire of an electrical coil, at least one portion of the overmoulded teeth being surrounded by an electrical coil once the bundle of ferromagnetic laminations that form same has been overmolded, the stator support having, at the front end of the teeth, a tubular casing defining a cylindrical cavity for receiving a rotor, characterised in that the overmoulded stator support is at least partially closed by a transverse disc-type partition having an axial sleeve for centring the shaft of the rotor, and in that the outer surface of the transverse disc-type partition, opposite the cylindrical cavity of the rotor, has means for mechanically fastening at least one of the electrical elements made up of: - the conductive tracks for interconnecting the wires of the coils, and/or - the electronic board, and/or - the support studs for reversing the winding wire.

Inventors

  • PRÉAULT, Valentin
  • FOUCAUT, ANTOINE

Assignees

  • Moving Magnet Technologies

Dates

Publication Date
20260506
Application Date
20240607

Claims (16)

  1. Electric motor comprising a stator (100) comprising a plurality of radial teeth (120) constituted by packs of ferromagnetic sheets and overmolded to form an overmolded stator support (150), said stator support (150) having between each tooth (120) a notch (135) provided to accommodate the wire (131) of an electric coil (130), at least part of said overmolded teeth (120) being surrounded by an electric coil (130) after overmolding of the pack of ferromagnetic sheets constituting it, said stator support (150) having, at the front end of the teeth, a tubular casing (141) delimiting a cylindrical cavity (250) to receive a rotor (200), characterized in that said overmolded stator support (150) is closed at least partially by a transverse disc partition (151) having an axial sleeve (152) for centering the shaft (350) of the rotor (200), and in that the outer surface of said transverse disc partition (151), opposite the cylindrical cavity (250) of the rotor (200), has means for mechanically fixing at least one of the electrical elements consisting of: the conductive tracks (610, 620, 630) for interconnecting the wires of the coils and/or the electronic card (400) and/or the support pads (650) for the winding wire to be turned back.
  2. Electric motor according to claim 1 characterized in that the stator support (150) is constituted by a single ferromagnetic sheet pack having a plurality of radial teeth (120), said overmolded stator support (150) being surrounded by a ferromagnetic stator crown (110) and in that the electric coils (130) are formed of a wire (131) wound on said overmolded teeth (120) of said single ferromagnetic sheet pack.
  3. Electric motor according to claim 1 characterized in that said axial centering sleeve (152) is formed by a tubular neck with a closed bottom.
  4. Electric motor according to claim 1 characterized in that said axial centering sleeve (152) is formed by a tubular neck with an open bottom.
  5. Electric motor according to any one of claims 1 to 3, characterized in that said axial centering sleeve (152) is capable of receiving a bearing (230) for guiding the shaft (350) of said rotor (200).
  6. Electric motor according to any one of claims 1 to 3, characterized in that said axial centering sleeve (152) comprises a smooth bearing for guiding the shaft (350) of said rotor (200).
  7. Electric motor according to any one of claims 1 to 3, characterized in that said axial centering sleeve (152) comprises a passage crossed by the shaft (350) of said rotor (200).
  8. Electric motor according to claim 1 characterized in that said transverse disc partition (151) is connected to the tubular casing (141) of the stator support (150) by a plurality of deformable zones (159).
  9. Electric motor according to the preceding claim, characterized in that said deformable zones (159) are in the form of connecting arms inclined relative to the radius.
  10. Electric motor according to claim 8 characterized in that said connecting arms are linked to the tubular casing (141) of the stator support (150) in a zone centered on a tooth.
  11. Electric motor according to claim 1 characterized in that the stator support (150) has anchoring means (157) located between two consecutive notches (135).
  12. Electric motor according to the preceding claim, characterized in that said anchoring means (157) consist of fixing eyelets located in radial extensions (145) of the stator support (150).
  13. Electric motor according to the preceding claim, characterized in that said anchoring means (157) consist of axial studs.
  14. Electric motor according to claim 1, characterized in that said tubular casing (141) has between each tooth (120) an axial weakening groove (146) to allow angular elastic movement of said teeth on either side of the radial reference plane.
  15. Electric motor according to claim 1 characterized in that the inner surface of said transverse disc partition (151), closing the cylindrical cavity (250) of the rotor (200), has stiffening ribs (171) to prevent warping of the transverse disc partition (151).
  16. Electric motor according to the preceding claim and claim 8, characterized in that the connecting arms constituting the deformable zones (159) are extensions of the stiffening ribs (171).

Description

Electric motor with improved assembly Field of invention The present invention relates to the field of electric motors, and in particular electric motors for fans. One of the manufacturing techniques for such motors consists of providing a crown-shaped plastic coil support in which teeth are inserted, consisting of stacks of ferromagnetic sheets magnetically connected by a yoke. These overmolded teeth are surrounded by a winding wire, generally made of copper insulated by a varnish. The wires of these coils are connected by metal tracks welded to the wires of each of the coils according to an appropriate topology. This type of motor has several drawbacks such as the axial size resulting from the inter-coil connection, as well as the number of parts to be assembled during manufacturing, and complex assembly processes to ensure reliability, robustness and competitive industrialization. State of the art Disadvantages of the prior art Solution provided by the invention General principle of the invention Compensation for overmolding shrinkage. Loose teeth Attachment points Second example of realization In particular, patent application WO2003081755A1 is known in the prior art, which relates to a stator intended for an electric motor, in particular for a high-power low-voltage motor of the external armature motor type, and which comprises a stack of stator laminations provided with a multitude of stator grooves and stator teeth for housing stator windings, as well as an interconnection system for interconnecting the wires of the stator windings. The stator windings wound around the stator teeth through the stator grooves overhang the stack of stator laminations by a winding head on both end faces. The interconnection system consists of winding contact elements as well as interconnection contact elements, the interconnection contact elements at least being arranged on one end face of the stator lamination stack substantially within a space delimited by the stator windings and by a plane defined by the winding head. US patent application US2012098363 relates to a pot-shaped stator support, on the radial outer side of which a stator base body is arranged. This stator base body has an inner yoke ring, from which stator teeth formed in one piece with the yoke ring project radially outwards. Insulating coil bodies wound with coils are connected and snapped radially from the outside onto the stator teeth, and on the radial outer side of the coil bodies, receiving pockets for insulation displacement elements of an interrupting ring, which extend in the axial direction, are formed in one piece on the coil body. US Patent US10243434 discloses a stator of an electric motor comprising a core, and a coating overmolded on the core. The mold for overmolding the coating on the core comprises first and second portions defining a cavity and pluralities of first and second pins extending at least generally to some opposed portions among the portions defining a cavity. The cavity is configured to receive the core. The first pins and the second pins are configured to extend into the cavity when the mold is in a closed position so as to at least partially secure the core in the cavity. The solution proposed by application WO2003081755A1 is complicated to industrialize: it involves positioning and inserting contact elements in the coil support, going around these contact elements with the winding wire, cutting the winding wire between certain coils and taking up a new winding, and interconnecting the contact elements with interconnection blades coming in excess of these contact elements. This therefore involves handling a large number of parts during the assembly phase, and a bulk resulting from the space taken up by these contact elements in erection above the plane of the winding wires. The solution proposed by the American patent application US2012098363 does not allow continuous winding with the same wire of all the coils already in place. It involves the implantation of coils already wound, then the installation of a peripheral interconnection assembly, then the welding of the two wires of each coil on this peripheral interconnection assembly before closing with a sealing ring. The solution proposed by patent US10243434 concerns an external rotor motor. Such motors are not satisfactory because the external rotor has a high inertia, and causes harmful noise; in addition, the solution proposed in this patent has the disadvantage of the difficulty of ensuring the winding on the stator body and of ensuring the interconnection of the wires of the stator coils. In addition, the connections between the winding wires and the printed circuit are located in the volume in which the rotor is arranged. The object of the present invention is to overcome these drawbacks and concerns an electric motor comprising a stator comprising a plurality of radial teeth constituted by packs of ferromagnetic sheets and overmolded to form an overmolded stator