Electric motor with improved assembly

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.

Description

Electric motor with improved assembly Field of invention

[0001] The present invention relates to the field of electric motors, and in particular electric motors for fans.

[0002] One of the manufacturing techniques for such motors consists of providing a crown-shaped plastic coil support into 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 disadvantages 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

[0003] Known in particular in the state of the art is patent application WO2003081755A1 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.

[0004] 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 integrally with the yoke ring project radially outward. 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 integrally on the coil body.

[0005] US Patent US10243434 discloses a stator of an electric motor comprising a core, and a coating overmolded onto the core. The mold for overmolding the coating onto the core comprises first and second portions defining a cavity and pluralities of first and second pins extending at least generally toward some opposed ones of 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 the closed position so as to at least partially secure the core in the cavity. Disadvantages of the prior art

[0006] The solution proposed by application WO2003081755A1 is complicated to industrialize: it involves positioning and inserting contact elements into 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 that come in excess of these contact elements. This therefore involves the handling of 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.

[0007] The solution proposed by US patent application US2012098363 does not allow continuous winding with the same wire of all the coils already in place. It involves the installation of already wound coils, then the installation of a peripheral interconnection assembly, then the soldering of the two wires of each coil on this peripheral interconnection assembly before closing with a sealing ring.

[0008] 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; moreover, the solution proposed in this patent has the disadvantage of the difficulty of ensuring the winding on the stator body and 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. Solution provided by the invention

[0009] The object of the present invention is to overcome these drawbacks and relates to 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 support, said stator support having between each tooth a notch provided to receive the wire of an electric coil, at least part of said overmolded teeth being surrounded by an electric coil after overmolding of the pack of ferromagnetic sheets constituting it, said stator support having, at the front end of the teeth, a tubular envelope delimiting a cylindrical cavity to receive a rotor, characterized in that said overmolded stator support is closed at least partially by a transverse disc partition having an axial sleeve for centering the rotor shaft, and in that the outer surface of said transverse disc partition,opposite the cylindrical cavity of the rotor, has means of mechanical fixing of at least one of the electrical elements consisting of:,

[0010] - the conductive tracks for interconnecting the coil wires and / or

[0011] - the electronic card and / or

[0012] - the support pads for the winding wire turning back.

[0013] In particular, it relates to an electric motor having all or part of the following characteristics.

[0014] The stator support is constituted by a single ferromagnetic sheet pack having a plurality of radial teeth, said overmolded stator support being surrounded by a ferromagnetic stator ring and in that the electric coils are formed of a wire wound on said overmolded teeth of said single ferromagnetic sheet pack.

[0015] Said axial centering sleeve is formed by a tubular neck with a closed bottom.

[0016] Said axial centering sleeve is formed by a tubular neck with an open bottom.

[0017] Said axial centering sleeve is capable of receiving a guide bearing for the shaft of said rotor.

[0018] Said axial centering sleeve comprises a smooth bearing for guiding the shaft of said rotor.

[0019] Said axial centering sleeve comprises a passage crossed by the shaft of said rotor.

[0020] Said transverse disc partition is connected to the tubular casing of the stator support by a plurality of deformable zones.

[0021] Said deformable zones are in the form of connecting arms inclined relative to the radius.

[0022] Said connecting arms are connected to the tubular casing of the stator support in an area centered on a tooth.

[0023] The stator support has anchoring means located between two consecutive notches.

[0024] Said anchoring means consist of fixing eyelets located in radial extensions of the stator support.

[0025] Said anchoring means consist of axial studs.

[0026] Said tubular envelope has between each tooth an axial weakening groove to allow angular elastic movement of said teeth on either side of the radial reference plane.

[0027] The inner surface of said transverse disc septum, closing the cylindrical cavity of the rotor, has stiffening ribs to prevent warping of the transverse disc septum.

[0028] The connecting arms constituting the deformable zones are extensions of the stiffening ribs.

[0029] Detailed description of a non-limiting example of embodiment

[0030] The present invention will be better understood on reading the following description, concerning a non-limiting example of embodiment illustrated by the appended drawings where:

[0031] represents a partial exploded sectional view of an exemplary embodiment of an engine according to a first variant embodiment of the invention,

[0032] represents an exploded three-quarter front view according to the first variant embodiment of the invention,

[0033] represents a more partially exploded, three-quarter rear view according to the first variant embodiment of the invention

[0034] represents a perspective view, three-quarters above, of the stator support before winding according to the first variant embodiment of the invention,

[0035] represents a perspective view, three-quarters above, of the stator support after winding according to the first variant embodiment of the invention,

[0036] represents a view from below of the stator support before winding according to the first variant embodiment of the invention,

[0037] represents a partial exploded sectional view of an exemplary embodiment of an engine according to a second variant embodiment of the invention,

[0038] represents a view, from below, of the stator support before winding according to the second variant embodiment of the invention,

[0039] represents a perspective view, three-quarters above, of the stator support after winding and insertion of the stator crown according to the second variant embodiment of the invention,

[0040] represents a view from below of the stator support before winding according to the second variant embodiment of the invention,

[0041] represents a sectional view according to the second variant embodiment of the invention, General principle of the invention

[0042] The invention relates to a motor consisting of a stator assembly (100) with overmolded teeth (120) surrounded by coils, forming a tubular casing (141) defining a cylindrical cavity (250) in which the rotor (200) rotates.

[0043] The invention of which the represents a non-limiting example, relates more particularly to the configuration of the stator assembly, (100) consisting of a set of overmolded teeth (120), with coils wound on the overmolding of the teeth (120), and a ferromagnetic stator crown (110) to form a tubular part which is distinguished from the prior art by the fact that it is closed by a transverse disc partition (151), which can be perforated, and which fulfills a main function of centering a rotor (200) relative to the stator (100), and an additional function of holding certain of the electrical elements of the stator by means of the reliefs, in the form of protuberances (155) or cavities formed on one of the surfaces of the transverse disc partition (151).

[0044] Thus, the stator block (100) forms a single plastic part overmolding the ferromagnetic teeth, to form a robust component directly ensuring the centering of the rotor relative to the wound teeth, as well as a robust connection of the electrical elements supplying the coils, and resistant to vibrations and other disturbances.

[0045] The axis is centered by an axial sleeve (152), which can be open or with a closed bottom. The axis is guided inside this sleeve in a conventional manner, for example by a rolling bearing or a plain bearing.

[0046] In order to avoid deformation of the stator part due to the plastic injection process, an optional solution consists of providing for the transverse disc partition (151) of the stator part deformable peripheral zones, in the annular zone between the periphery of the transverse disc partition and the tubular casing (141) for example peripheral recesses alternating with radial beams, or inclined arms allowing the transverse disc partition to take its dimension after overmolding without breaking the disc part if it is too constrained by the tubular casing, nor deforming this tubular casing in the event of reduction of the diameter of the disc partition by shrinkage of the plastic during cooling.

[0047] According to another optional variant the stator assembly is configured to allow angular movement of the teeth, in order to reduce the noise caused by the detent torque when changing from one step to the next.

[0048] This angular movement is obtained by a local weakening of the overmolding, for example by the formation of lights (175) at the periphery of the transverse disc partition (151), and / or by axial grooves (146) formed between the teeth (120) in the tubular casing (141).

[0049] Each tooth (120) is formed by a block of stacked overmolded sheets forming the insulated body receiving the winding after overmolding.

[0050] The teeth (120) are preferably overmolded, leaving the rear face flush, to come into mechanical and magnetic contact with a ferromagnetic stator ring (110) surrounding the tubular casing, and preserving, between each tooth, a notch (135) allowing the passage of the winding wire before the installation of the ferromagnetic stator ring.

[0051] Optionally, the teeth can also radially extend a tubular crown, the ferromagnetic assembly then being overmolded. In this case, the winding is then knitted by alternately passing the wire up and down, around the body formed by each overmolded tooth, or from notches provided on the inner surface of the overmolded assembly.

[0052] Optionally, the tubular stator part has anchoring means (157) located in the extension of the teeth, advantageously between two consecutive notches (135). These anchoring means (157) can take the form of radial extensions (145) having fixing eyelets or the form of axial studs, or any other geometric shape capable of ensuring: An attachment of the stator assembly, or even of the motor as a whole, And, in certain variants, a stop for the ferromagnetic stator ring.

[0053] The reliefs formed on the surface of the transverse disc partition (151) have, for some, support pads (650) for the turning back of the winding wire, and others have the form of ribs (158) and can ensure a raising of certain sections of the winding wire, to prevent them from coming into contact with the conductive tracks (610, 620, 630) provided on the surface of the transverse disc partition (151) and causing a short circuit when the wire is accidentally stripped or delaminated, or can also be used for positioning the conductive tracks (610, 620, 630). The reliefs can also be made up of pins (154) intended to ensure a function of holding the conductive tracks (610, 620, 630) by riveting on the upper part of these pins (154).Finally, but still in a non-limiting manner, the reliefs can be cylindrical protuberances (155) provided with drilling to constitute a means of anchoring an electronic card (400) electrically connected to the connection assembly (600).

[0054] Detailed description of a first example of implementation

[0055] The embodiment described with reference to figures 1 to 6 concerns a “pancake” type electric motor used for fans, in particular for forced ventilation functions, and particularly that of polyphase motors with electronic commutation with pilot control integrated into the motor housing and coils exposed to the air flow to allow optimal cooling.

[0056] The solution which is the subject of the present invention is particularly interesting for the construction of a motor of low thickness and high power (greater than 1 KW) used for example for the cooling of the components of a rapid charging device for an electric vehicle, but it can be used for any type of ventilation or pump drive motor allowing the benefit of the fluid flow to cool the stator coils located in the space exposed to the air flow.

[0057] This represents an exploded view of the motor, without its propeller. It consists of: a stator assembly (100), a rotor (200), a guide flange (190).

[0058] The stator assembly (100) is provided with an overmolded stator support (150) having a generally tubular part comprising the overmolded teeth (120), one of the axial ends of this tubular part is closed transversely by a transverse disc partition (151) comprising an axial sleeve (152) for centering and guiding the rotor (200).

[0059] The surface area of ​​this transverse disc partition (151) is greater than 50% of the surface area of ​​the interior cavity of the tubular casing (141), with solid parts directly connecting the guidance of a central axis and connection zones with the tubular casing (141), without the interposition of an additional part fixed to the stator part, to avoid any risk of deformation as well as to reduce tolerances and industrialization difficulties.

[0060] At the axial end opposite this transverse disc partition (151), the overmolded stator support (150) is closed by a guide flange (190) which is preferably fixed by laser welding or heat welding.

[0061] The rotor (200) has a shaft (350) which is guided on the one hand by the transverse disc partition (151) and on the other hand by the guide flange (190).

[0062] The stator support (150) is constituted by an overmolding, by injection of a plastic material, of a set of radial teeth (120) also formed by a pack of sheets, flush with the outer periphery to come into mechanical and magnetic contact with a peripheral stator crown (110) surrounding the stator support (150). This overmolding makes it possible to constitute coil bodies (140), making it possible to produce the winding generating the magnetic field interacting with the rotor (200).

[0063] These coil bodies (140) extend radially along the teeth from the tubular casing (141), the inner surface of which coincides with the front of the teeth (120), to the peripheral radial end, called distal, of the teeth. The coil bodies thus form a thin casing along the teeth, intended to ensure good electrical insulation between the coil wire and the stack of ferromagnetic sheets constituting the teeth. The radial extension of the coil bodies is done along the teeth (120) with a minimal thickness making it possible to maximize the space intended for the electric coils (130) while ensuring electrical insulation between the coils (130) and the stack of sheets of the teeth (120). At the front end of the teeth, the tubular casing (141) extends axially to provide a front bearing surface for the wire during the winding operation.The axial extension of the tubular envelope (141) projecting from the transverse disc septum (151) forms a frontal annular extension (148).

[0064] The transverse disc partition (151) and the frontal annular extension (148) form an inner zone (170) intended to receive the end of the winding wires to ensure their electrical connection. For this purpose, the frontal annular extension (148) is provided with notches (), or slots, to allow the passage of the winding wire between the coil body (140) and the inner zone (170), while ensuring axial and transverse guidance of the latter. At the distal end of the teeth, the coil bodies (140) extend axially and tangentially, over the desired coil extent, so as to provide a distal support zone for the coil wires (130). The distal tangential extension of the coil bodies (140) takes place on peripheral angular sectors (142) which are not contiguous between the teeth (120), but leave a free angular sector (143) to facilitate the path of the wire during the winding operation.

[0065] In its internal part, said tubular casing (141) defines, on the side of the transverse disc partition (151) opposite the internal zone (170), a cylindrical cavity (250) for receiving the rotor (200). This cylindrical cavity (250) can be closed, on the side opposite the transverse disc partition (151), by a guide flange (190).

[0066] The axial sleeve (152) is traversed by a central shaft (350) intended for centering and guiding the rotor (200). The shaft (350) is connected to the rotor (200) and guided by bearings (230, 240) provided respectively in the axial sleeve (152) formed on the transverse disc partition (151) and in a housing (195) of the guide flange (190).

[0067] In the example presented, the stack of sheets constituting the teeth is produced in a single assembly in the form of a tubular ring extended radially by the teeth. At the level of the tubular casing (141), the overmolding axially adjoins the internal periphery of the tubular ring. The skilled person could nevertheless imagine variants for which the teeth would not be joined by the stack of sheets, but would be secured by the plastic overmolding. The tubular ring would therefore be formed from the end of the teeth connected by arcuate sections in overmolding. It could also be imagined that the front end of the teeth would be covered with overmolding resin to protect the stack of sheets from the teeth, this operation nevertheless being accompanied by an increase in the magnetic air gap and therefore a reduction in the performance of the machine.

[0068] Detailed description of the transverse disc septum (151)

[0069] As illustrated by figures 1 to 6, in addition to the function of centering the rotor (200), previously described, the transverse disc partition (151) has an additional function of mechanically fixing electrical elements of the stator, which can in particular be in the form of reversal points of the single winding wire, means of fixing the interconnection tracks of the coils, or even the means of fixing the electronic card (400) for controlling the motor by electrical power supply of the coils.

[0070] In the illustrated examples, notably visible in figures 4 and 5 for the first embodiment, the upper surface of the transverse disc partition (151) has pins (154), constituting plastic rivets for fixing by plastic riveting of the inter-coil connection tracks (610, 620, 630) which will be detailed below. The conductive tracks (610, 620, 630) are fixed before the start of winding.

[0071] The transverse disc septum (151) is delimited on its periphery by a frontal annular extension (148) axially extending the tubular envelope (141) so as to form an interior zone (170).

[0072] The front annular extension (148) is provided with notches (149) at each coil (130) to allow the winding wire (131) to reach the inner zone (170) from the coil body (140) and vice versa. As shown in Figures 1 to 6, the notches (149) can extend angularly over a significant portion of the coil body (140), the two wires (131) constituting the ends of the coil (130) passing through the front annular extension (148) in the same notch (149). The notch (149) then provides a zone of maximum transverse movement of the wires (131), but any other alternative is envisaged, such as that for example shown in 9 where the wires are guided in individual notches to wedge them transversely.

[0073] Detailed description of coil interconnection

[0074] In the general case, each coil (130) has a pair of wires (131) passing through the frontal annular extension (148) of the tubular casing (141).

[0075] In special cases, two or more coils are connected in series by a continuous and unstripped wire, and in this case, the connecting wire between the coils does not need to be passed back over the transverse disc partition (151), thus the pair of wires extending radially will correspond to the set of coils in series. This remark is all the more valid if the coils connected in series are adjacent, but the skilled person could also find ways to connect in series a set of non-adjacent coils using a continuous wire, while ensuring routing compatibility with respect to the sets of the other phases.

[0076] In a preferred embodiment, and described in this example, the winding of the teeth is carried out by a single continuous wire, successively running through the coils and forming loops inside the inner zone (170), where the wire surrounds interconnection support pads (650). These support pads (650) are constituted by protuberances formed on the surface of the transverse disc partition (151) or can also extend from a conductive track (610, 620, 630) making it possible to carry out both the turning back of the wire and its electrical connection to the conductive track by a soldering operation removing its insulating layer. During winding, the winding needle drives the winding wire (131) from the newly wound bobbin (130) to the surface of the transverse disc partition (151) through a notch (149) made in the tubular casing (141).The needle then reaches a support stud (650), which it goes around, then drives the wire back towards the periphery to start winding the next coil. Note that all the support studs (650) are distributed on a circle located between two conductive tracks (620, 630), so when the wire reaches the inner zone (170) to be connected to the conductive track (630) inscribed in the distribution circle of the support studs (650), it goes around a metal support stud extending the conductive track (630) so as to ensure the mechanical guidance and electrical contact functions in a single piece. The metal support studs (650) are in the form of a "V" whose leaves are made up of folded sections of the metal track, the wire passes through the groove formed by this "V" and makes the reversal by winding itself on one of the leaves.During the electrical welding operation, the leaves can be slightly folded back to improve electrical contact. The electrical connection means (660) of the other tracks are in the same form as the metal support pins, the wire simply passing through the groove formed by the two leaves to go around the appropriate support pin.

[0077] In the example described, the motor has three phases, resulting in an interconnection of the coils for groupings by means of a connection assembly (600) formed of three conductive tracks (610, 620, 630) cut from the same conductive sheet and folded to constitute the support pins (650) and electrical connection or the electrical connection means (660).

[0078] The conductive tracks (610, 620, 630) are placed on the transverse disc partition (151) before winding. They are fixed on the transverse disc partition (151) by riveting on the pins (154) and positioned angularly by the ribs (158) which also ensure a raising of the winding wire, to prevent the wire from coming into contact with the conductive tracks (610, 620, 630) and causing a short circuit when it is accidentally stripped or delaminated. It can be noted that the notches (149) also make it possible to ensure a raising of the wire by constituting an axial support.

[0079] As more particularly visible in, the wire (131) alternately passes through the coils (130) and the connection assembly (600) during winding by an automaton, without breaking the wire.

[0080] In order to ensure optimum tension, the wire (131) is anchored at a starting point (640) consisting of a flared shape in which the start of the wire is engaged and held by wedging. It then passes radially through the frontal annular extension (148) through a notch (149) provided, and then winds onto a first coil body (140) formed by the overmolding of a first tooth (120), before radially joining the transverse disc partition (151) by passing again through a notch (149) of the frontal annular extension (148). Inside the inner zone (170), it joins the central part by possibly engaging in the groove of an electrical connection means (660), bypasses a support pad (650), before returning radially towards another coil (130) adjacent to the previous one, after having crossed the frontal annular extension (148) by another notch (149).

[0081] The wire (131) then winds the second tooth, before radially joining the inner zone (170) by passing again through a notch (149) of the frontal annular extension (148). Inside the inner zone (170), it joins the central part by possibly engaging in the groove of an electrical connection means (660), goes around a support pad (650), before returning radially towards another coil (130) adjacent to the previous one; and so on.

[0082] The electrical connection to the conductive tracks (610, 620, 630) can, without great importance, take place upstream, downstream or at the same time as bypassing the support pin (650).

[0083] In the most general case, the wire (131) passes through the frontal annular extension (148) before and after each coil (130). However, in the case where certain coils (130) are connected in series, whether consecutive or not, the wire (131) passes through the frontal annular extension (148) only to ensure the connections between a coil and a track (610, 620, 630), but not for the direct connections of two coils (130), in order to reduce the passages and therefore the number of electrical welds carried out.

[0084] In an advantageous configuration, the coil bodies (140) are striated so as to guide the wires and facilitate winding; this is particularly interesting in the case of winding wires of large cross-section and therefore of great rigidity.

[0085] Inferior surface of the transverse disc septum (151)

[0086] As illustrated in, for the first embodiment and infor the second embodiment, the lower surface of the transverse disc partition (151), located in the cylindrical cavity (250) receiving the rotor (200), has stiffening ribs (171).

[0087] These stiffening ribs (171) extend to the front and / or rear surface of the transverse disc partition (151) to stiffen this transverse disc partition (151) and avoid the risk of warping due, for example, to torsional forces exerted by the rotor axis on the axial sleeve (152). These stiffening ribs (171) may extend radially or have geometries adapted to avoid warping of this transverse disc partition (151).

[0088] The presence of these stiffening ribs (171) can also help to improve the transfer of plastic material from an injection point to the entire volume of the part. Compensation for overmolding shrinkage.

[0089] The stator assembly (100) is formed by plastic injection into a mold for overmolding the ferromagnetic teeth (100). The transverse dimension of the transverse disc partition (151) causes a shrinkage phenomenon during crystallization and cooling of the part after overmolding, which can lead to deformation of the tubular casing (141) and by extension of the overmolded stator support (150), between one of the ends which is open, and the other end closed by the transverse disc partition (151) and subjected to centripetal forces causing a slight conicity.This conicity alters the geometry of the overmolded stator support (150), resulting in the fact that the front surfaces of the teeth may no longer come into optimal contact with the ferromagnetic stator crown (110) on the one hand, and / or degrade the constancy of the magnetic air gap between the teeth and the rotor, or even cause breakages which may lead to guidance or sealing defects.

[0090] To compensate for this shrinkage, the invention proposes to provide deformable zones (159) at the periphery of the transverse disc septum (151), at its connection with the tubular envelope (141). These deformable zones (159) can result from an annular alignment of slots (175), preferably arranged between two consecutive teeth (120), alternating with arms angularly centered on a tooth (120). These deformable zones (159) can also consist of oblique arms arranged with a constant angular pitch, to allow, in the event of shrinkage of the transverse disc septum, a slight angular displacement of the central zone relative to the tubular envelope (141). These oblique arms connect a zone of the tubular envelope (141) centered on a tooth (120) to a point angularly offset by 10 to 40° from the periphery of the central zone of the transverse disc septum (151).The deformable zones (159) preferably extend in the extension of the stiffening ribs (171). Indeed, the deformable zones must make it possible to absorb the contraction deformations of the transverse disc partition (151), while the stiffening ribs (171) must avoid out-of-plane deformations of said transverse disc partition (151), geometries are therefore compatible to meet these two functions with a single part, for example a rectangular beam extending radially can have good deformation capabilities in compression or in tangential bending while resisting axial bending. Loose teeth

[0091] The alternation of slots (175) and deformable zones (159) on the periphery of the transverse disc partition (151) also makes it possible to create weakening zones between the teeth (120), allowing a slight angular movement of said teeth (120) by the elastic deformation of the overmolding. This weakening can also be obtained or accentuated by axial grooves (146) formed in the outer periphery of the tubular casing (141) in the center of the notches (135). This angular play has, surprisingly, the effect of avoiding transmitting to the stator crown (110) the transverse forces resulting from the periodic interaction between the magnets and the teeth, a source of noise. Anchor points

[0092] The stator assembly (100) is fixed to a support or to a housing by means of extensions (145) of the overmolded stator support (150). These extensions (145) are located in an angular zone delimited by the peripheral angular sectors (142) and preferably along a radius passing through the center of a tooth (120). In contrast, the extensions are not located in a free angular sector (143) located between two consecutive teeth. The extensions may nevertheless be located in a radius between the wound part of a tooth and the transverse disc partition (151) or on the external periphery of a tooth (120), for example above the stator crown (110). This arrangement makes it possible not to clutter the inter-tooth space, i.e. the free angular sectors (143), so as to facilitate the winding operation. This also makes it possible to better absorb the forces introduced by the rotor on the ferromagnetic teeth (120).In a non-limiting manner, the attachment to the support is carried out by anchoring means (157) by the intervention of forms of riveting pins or plastic riveting extending the extensions (145) in the axial direction. The extensions (145) can also extend radially in the form of ears pierced with an eyelet or having a threaded bore acting as anchoring means (157). Second example of realization

[0093] This second example is an alternative embodiment which differs from the example previously described by the fact that the transverse disc partition (151) has a sealed interior zone (170). The other characteristics previously described generally apply to this second example embodiment and variations are explained in the following paragraphs. This alternative embodiment is to be observed with regard to figures 7 to 11.

[0094] To ensure the sealing of the inner zone (170), the transverse disc partition (151) has two concentric rings (161, 162), forming a frontal annular partition (160), located at the inner periphery of the deformable zones (159), defining between them an annular groove (163). The rings (161, 162) are indented by radial slots (164, 165) respectively to allow the radial passage of the wires (131) of the coils (130) and their guidance at the time of winding of the stator support (150). The top of the peripheral ring (162) has anchoring housings (166) for the engagement of positioning hooks and attachment of a deformable indented toric part (180), for example made of elastomer.

[0095] This toric part (180) has a lower part formed by two coaxial lips (181, 182), straddling said peripheral crown (162), the lip (182) being inserted into the annular groove (163), and an indented upper part being locally crossed by the radial wires of the coils (130), the width of the indentation slots being less than the section of the winding wire (131) to ensure a sealed pinching of the wire.

[0096] This toric part (180) has on either side of each indentation slot a cavity opening onto the adjacent slot to allow filling with a glue or a resin ensuring sealing after insertion of the winding wires (131).

[0097] These indentation slots fit the side walls of the slots (165) of the peripheral crown (162).

[0098] The bottom of the slots (165) of the peripheral crown (162) each have a projection of the same width as the cavities to form a support for the winding wire (131) and prevent it from causing shearing of the bottom of the toric part (180) during winding and a potential loss of sealing of the front annular partition (160).

[0099] When the wires are all in place, the sealing of the inner zone (170) is perfect by an additional seal (800), for example made by the deposit of an adhesive or silicone, placed between the periphery of the front annular partition (160) and the transverse part (300). The annular configuration of the toric part (180) makes it possible to deposit this seal (800) over its entire upper face in a single continuous dosage so as to ensure perfect sealing while limiting its production cost.

[0100] The transverse part (300) has an annular protrusion (320) of a shape complementary to that of the frontal annular partition (160), or to the toric part (180) covering it, to ensure a sealed peripheral barrier of the interior zone (170).

[0101] This embodiment corresponds to an advantageous example but it is understood that other solutions for sealing the passage of the wires (131) are possible. For example, the annular groove (163) between the rings (161, 162) could be filled by a deposit of glue or silicone which can be forced inside the slots (164, 165) by piston effect during assembly with the transverse part (300) thanks to a shape complementary to said space and located on said transverse part. This second solution would nevertheless be more expensive because it would require a much larger deposit of glue, a material known to be expensive. Other alternatives would be the deposit of a crown of resin or silicone on the stripped area of ​​the wires (131), or even that the peripheral ring does not surmount the surface of the stator support, but is a frontal annular partition formed on the lower surface of the transverse part (300).

[0102] The transverse part (300) has in its upper part a housing to accommodate the electronic card (800), this housing is closed by a ca300pot (500), for example metallic.

[0103] As shown in, the stator ring (110) is positioned by axial insertion, such that the outer surface of the teeth (120) comes into mechanical and magnetic contact with the inner surface of the stator ring (110) to ensure closure of the magnetic flux. The stator ring (110) is then held in position by the flexible extensions (156).

[0104] In a direction opposite to the extension of said flexible extensions (156), part or all of the extensions (145) have an anchoring means (157) ensuring the connection by riveting with the transverse part (300).

[0105] The winding method differs in several points, firstly the wire must pass through the rings (161, 162) through the slots (164, 165) to reach the inner area (170) containing the conductive tracks (610, 620, 630). This embodiment also differs in that the support pads (650) are all folded extensions of the conductive tracks (610, 620, 630).

[0106] Each support pad (650) is associated with an electrical connection means (660) in the form of a deformable lug which is folded back, after the passage of the wire (131), against the wire (131) surrounding the support pad (650) to provide a welding point locally removing the insulation coating of the wire. The support pads (650) and the electrical connection means (660) are produced by local deformations of the metal track (610, 620, 630).

[0107] As for example shown in, the shaft (350) can alternatively be rigidly connected to the transverse disc partition (151), the rotor rotating around the shaft (350) by means of bearings (230, 240) integrated in housings of the rotor (200). The central shaft is fixedly mounted in a guide nose (330) of the transverse part (300) which is inserted into the axial sleeve (152) of the transverse disc partition (151). In this case the transverse disc partition (151) acts as a centering role for the rotor (200) relative to the stator.

Claims

Electric motor comprising a stator (100) comprising a plurality of radial teeth (120) constituted by packets 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 receive the wire (131) of an electric coil (130), at least a portion of said overmolded teeth (120) being surrounded by an electric coil (130) after overmolding of the packet 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) of centering of 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 turning back the winding wire., Electric motor according to claim 1 characterized in that the stator support (150) is constituted by a single pack of ferromagnetic sheets having a plurality of radial teeth (120), said overmolded stator support (150) being surrounded by a ferromagnetic stator ring (110) and in that the electric coils (130) are formed of a wire (131) wound on said overmolded teeth (120) of said single pack of ferromagnetic sheets. Electric motor according to claim 1 characterized in that said axial centering sleeve (152) is formed by a tubular neck with a closed bottom. Electric motor according to claim 1 characterized in that said axial centering sleeve (152) is formed by a tubular neck with an open bottom. 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). 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). 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). 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). 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. 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 an area centered on a tooth. Electric motor according to claim 1 characterized in that the stator support (150) has anchoring means (157) located between two consecutive notches (135). 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). Electric motor according to the preceding claim, characterized in that said anchoring means (157) consist of axial studs. 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. 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). 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).

Images