Stator assembly for electronically commutated electric motor

Abstract

Stator (20) for an electric motor (14) of a ventilation device (10) for a motor vehicle, said stator (20) comprising:- a barrel (46) comprising a base (46a) fixed on a support (16), and- a stack of metal sheets (36),the barrel (46) comprising an internal channel (50) which passes right through the barrel (46) in the direction of an axis (A1), said internal channel (50) being intended to be passed through by a shaft (26) of a rotor (18),the internal channel (50) comprising at least one housing (51) intended to receive a bearing ring (52),the stator (20) further comprising an electrical connector (49) comprising:- a central part (49a) inserted into the at least one housing (51),- at least one leg (49b) starting from the central part (49a) and spanning the end of the cylindrical channel (50) of the barrel (46) so that the end of said leg (49b) comes into contact with the stack of sheets (36). Abstract figure: Fig 2

Description

Title of the invention: Stator assembly for an electronically commutated electric motor

[0001] The present invention relates to the field of a stator assembly for an electronically commutated electric motor. The present description also relates to an electronically commutated electric motor comprising such a stator assembly, to a ventilation device comprising such a motor and to a heating, ventilation and / or air conditioning installation, in particular for a motor vehicle, comprising such a ventilation device.

[0002] Motor vehicles are commonly equipped with a heating, ventilation and / or air conditioning system comprising a ventilation device for generating an air flow. Such an installation generally comprises a ventilation duct through which an air flow circulates. The air flow is generated by a propeller or fan wheel driven in rotation by an electric motor.

[0003] The electric motor is in particular an electronically commutated motor, or brushless direct current motor (also known under the English name “brushless”). The electric motor comprises a rotor and a stator, each carrying electromagnetic elements.

[0004] Thus, the stator generally comprises several windings supported by an insulator and surrounding a stack of laminations. When electric currents flow through the windings, magnetic fields are produced. The rotor is provided with a plurality of permanent magnets also producing magnetic fields. The interaction of the magnetic fields produced by the stator windings with the magnetic fields produced by the rotor magnets generates the displacement of the rotor relative to the stator, and further the rotation of the fan wheel.

[0005] A known problem with this type of motor is that, when using the motor, the electromagnetic radiation produced can interfere with the use of other electronic devices located nearby.

[0006] In order to limit the disturbances due to these electromagnetic radiations, a known solution is to connect to ground in particular the pack of sheets. However, such a connection can prove complicated and expensive due to the compactness of the electric motor.

[0007] One of the aims of the present invention is therefore to remedy at least partially the drawbacks of the prior art and to propose an electric motor stator whose connection to the ground of a pack of sheets is improved.

[0008] The present invention relates to a stator for an electric motor of a ventilation device for a motor vehicle, said stator comprising: - a barrel comprising a base fixed on a support, and - a stack of metal sheets, the barrel comprising an internal channel which passes right through the barrel in the direction of an axis, said internal channel being intended to be passed through by a shaft of a rotor, the internal channel comprising at least one housing intended to receive a bearing ring, the stator further comprising an electrical connector comprising: - a central part inserted into at least one housing, - at least one leg extending from the central part and spanning the end of the cylindrical channel of the barrel so that the end of said leg comes into contact with the stack of sheets.

[0009] According to one aspect of the invention, the end of the at least one leg is curved.

[0010] According to another aspect of the invention, the central part of the electrical connector is annular.

[0011] According to another aspect of the invention, the at least one housing comprises an internal rim on which the central part of the electrical connector rests, said central part being sandwiched and held in the housing by the rolling ring.

[0012] According to another aspect of the invention, the stator comprises an electrically conductive screen arranged at the opposite end of the base of the barrel and covering branches of said barrel as well as windings surrounding said branches, the screen and the electrical connector being made of one material from the other.

[0013] According to another aspect of the invention, the screen comprises: - an annular central recess inserted into the at least one housing and ending in the annular central part of the electrical connector, - a radial cutout starting from the central recess, the at least one leg of the electrical connector being formed by said radial cutout within the screen.

[0014] According to another aspect of the invention, the stator comprises a system of notches and lugs between the cylinder channel and the central recess of the screen.

[0015] According to another aspect of the invention, the support comprises a metal plate connected to the electrical ground, the stator further comprising an electrically conductive tab, said tab comprising: - a first end projecting from the barrel so as to come into contact with the stack of sheets, - an internal part overmolded in the wall of the barrel itself, and - a second end projecting from the base of the barrel and coming into contact with the metal plate, said tab having a continuous profile such that its first end and its second end are plumb with each other.

[0016] According to another aspect of the invention, the length of the second end of the tab is greater than the distance between its exit point from the base of the barrel and the metal plate.

[0017] The present invention also relates to an electric motor of a ventilation device for a motor vehicle comprising a stator as described previously.

[0018] Other characteristics and advantages of the present invention will appear more clearly on reading the following description, provided for illustrative and non-limiting purposes, and the appended drawings in which:

[0019] [Fig-1] [Fig.l] shows a schematic representation in perspective and in section of a ventilation device,

[0020] [Fig.2] [Fig.2] shows a schematic representation in side view and in section of a stator of an electric motor for the ventilation device of [Fig.l],

[0021] [Fig.3] [Fig.3] shows a partial schematic representation in perspective and in section of the stator of [Fig.2],

[0022] [Fig.4] [Fig.4] shows a schematic perspective representation of the stator of [Fig.2] with windings,

[0023] [Fig.5] [Fig.5] shows a schematic perspective representation of the stator of [Fig.2] with an electrical connector,

[0024] [Fig.6] [Fig.6] shows a schematic perspective representation of a electrical connector,

[0025] [Fig.7] [Fig.7] shows a schematic perspective representation of the stator of [Fig.5] according to a particular embodiment,

[0026] [Fig.8] [Fig.8] shows a schematic perspective representation of the stator of [Fig.2] with an electrical connector and a screen.

[0027] In the various figures, identical elements bear the same reference numbers.

[0028] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Single features of different embodiments may also be combined and / or interchanged to provide other embodiments without departing from the scope of the invention as defined by the claims.

[0029] In the present description, certain elements or parameters may be indexed, such as for example first element or second element as well as first parameter and second parameter or even first criterion and second criterion, etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria that are close, but not identical. This indexing does not imply a priority of one element, parameter or criterion over another and such names can easily be interchanged without departing from the scope of the present description. This indexing also does not imply an order in time for example to assess such or such criterion.

[0030] [Fig.l] schematically illustrates a ventilation device 10 (or fan) in section for a heating, ventilation and / or air conditioning installation of a motor vehicle.

[0031] The ventilation device 10 comprises a fan wheel 12, an electric motor 14, and a support 16 for the electric motor 14. The fan wheel 12 rotates about an axis AL. The electric motor 14 is intended to drive the fan wheel 12 in rotation about the axis Al. The support 16 for the electric motor 14 is in particular intended to allow the ventilation device 10 to be fixed in a motor vehicle, by limiting the transmission of vibrations generated by the electric motor 14 and / or the fan wheel 12 in the motor vehicle and / or external constraints towards the electric motor 14 and / or the fan wheel 12.

[0032] The electric motor 14 comprises a rotor 18 and an associated stator 20. This is an external rotor 18 in that it is associated with a stator 20 arranged radially inside the rotor 18.

[0033] The rotor 18 may in particular comprise a cup 22 symmetrical by rotation around the axis A1, in the shape of a bell. The rotor 18 also comprises magnets 24 fixed here to an internal face of the cup 22, in particular on a cylindrical strip of the internal face of the cup 22. The cup 22 of the rotor 18 is fixed, at its center, to a shaft 26 of axis A1. The shaft 26 constitutes the output (or rotation) shaft of the electric motor 14, driving the fan wheel 12. For this purpose, the fan wheel 12 is here directly fixed on the shaft 26.

[0034] The stator 20 can be symmetrical by rotation around the axis AL. The stator 20 comprises a barrel 46 extending mainly in the direction of the axis AL. The cup 22 of the rotor 18 in particular covers one end of the barrel 46 opposite its base 46a.

[0035] As illustrated in Figures 1 and 2, the barrel 46 comprises in particular a base 46a as well as an internal channel 50. The internal channel 50 passes right through the barrel 46 in the direction of the axis AL. The internal channel 50 may be generally cylindrical. The internal channel 50 comprises at least one housing 51 intended to receive a ring of bearings 52 in which the shaft 26 is inserted. Here, two housings 51 are formed in the internal channel 50 of the support 20. Each housing 51 is intended to receive a bearing ring 52, in particular a ball bearing. These housings 51 are more particularly arranged respectively at the ends of the internal channel 50. The shaft 26 is received partly in the internal channel 50 of the stator 20, free to rotate around the axis A1 relative to the stator 20, by means of the bearing rings 52. The bearing rings 52 can in particular be held within their respective housing 51 by means of an internal elastic ring such as a circlip.

[0036] The barrel 46 also comprises a plurality of branches 31 extending radially relative to the axis AL. The branches 31 notably project from the barrel 46. These branches 31 are for example arranged at an end of the barrel 46 opposite that covered by the cup 22 and project from the base 46a of the barrel 46. As illustrated in Figures 4 and 5, the barrel 36 here comprises twelve branches 31 distributed regularly around the axis. The branches 31 notably have a “T” shape with two lateral extensions 31a at their end opposite that connected to the barrel 46, as illustrated in [Fig.3]. The barrel 46 with these branches 31a thus has a generally star shape.

[0037] The barrel 46 and more particularly these branches 31 are made of an electrically non-conductive material, for example plastic. The barrel 46 may in particular be a single piece in that there is continuity of material between the branches 31 and the barrel 46. An alternative not shown may also be that the branches 31 are made on an independent part having an annular central part from which the branches 31 protrude and fixed to the barrel 46. The barrel 46 is for example made by molding, in particular by injection molding.

[0038] As illustrated in Figures 2 and 4, a stack of metal sheets 36 is arranged on the branches 31 of the barrel 46. These metal sheets 36 comprise in particular an annular central part 36a arranged around the barrel 46. The metal sheets 36 also comprise branches 36b having in particular a complementary shape with the branches 31 of the barrel 46.

[0039] The stator 20 also comprises an insulator 42 covering the stack of metal sheets 36. The insulator 42 has a shape complementary to the metal sheets 36. The insulator thus comprises an annular central part 42a arranged around the barrel 46 as well as branches 42b having in particular a shape complementary to the branches 31 of the barrel 46 and the branches 36b of the stack of metal sheets 36. The stack of metal sheets 36 is thus maintained and sandwiched between the branches 31 of the barrel 46 and the branches 42b of the insulator 42. The insulator 42 and more particularly these branches 42b are also made of an electrically non-conductive material.

[0040] The metal sheets 36 as well as the insulator 42 are integral with the barrel 46 so that these elements are fixed and cannot rotate around the first axis A1 relative to the barrel 46. This fixing between these elements can in particular be achieved by lugs cooperating with notches made on one or other of these elements of the stator 20.

[0041] The branches 31, 36b and 42b form a winding support around which at least one winding 30 is wound. Each winding 30 corresponds to a phase of the electric motor 14. A three-phase electric motor 14 thus comprises a multiple of three series of windings 30, here for example twelve. The windings 30 are made by windings of a metal wire, generally copper, surrounding the branches 31, 36b and 42b of the stator 20. These windings are made so as to be in contact only with the branches 31 of the barrel 46 and the branches 42b of the insulator 42 so as not to be in electrical contact with the stack of metal sheets 36. Each assembly formed by a branch 31 of the barrel 46, a branch 36b of the stack of metal sheets 36 and a branch 42b of the insulator 42 carries a respective winding of one of the windings 30. A three-phase electric motor 14 thus comprises three windings 30 whose respective windings are alternated.

[0042] The base 46a of the barrel 46 is in particular fixed to the support 16, for example by means of screws. This support 16 is also made of an electrically non-conductive material. The support 16 can also be symmetrical by rotation around the axis A1 and have a central opening within which the barrel 46 is fixed. The rotor 18 and in particular the external edges of the cup 22 can in particular pass directly above said support 16.

[0043] The electric motor 14 may also comprise a cover 17 symmetrical by rotation around the axis A1 arranged between the support 16 and the external edges of the fan wheel 12. This cover 17 comprises in particular a central opening through which the stator 20 and the rotor 18 pass.

[0044] Opposite a first face of the support 16 from which the barrel 46 projects, a printed circuit 45 can be fixed on a second face of the support 16, for example by means of screws. The printed circuit 45 comprises in particular electrical and electronic components in order to control the electric motor 14 and to ensure the electrical supply of the windings 30. Each winding 30 is electrically connected to the printed circuit 45 and to their electrical supply. This connection of the windings 30 can in particular be made by metal tabs not shown.

[0045] A metal plate 48 is arranged between the printed circuit 45 and the support 16. The metal plate 48 is connected to the electrical ground. The electrical connections of the windings 30 pass through the metal plate 48 without electrical contact through orifices (not shown).

[0046] In order to reduce disturbances due to electromagnetic radiation, the barrel 46 comprises an electrically conductive tab 47, for example a conductive metal, and overmolded therein. The tab 47 connects the stack of sheets 36 to electrical ground by making electrical contact with the metal plate 48. More particularly, the tab 47 comprises a first end 47a projecting from the barrel 46 so as to come into contact with the stack of sheets 36. More particularly, this first end 47a of the tab 47 comes into contact with the annular central part 36a of the stack of sheets 36, arranged around the barrel 46.

[0047] The tongue 47 comprises an internal part 47b overmolded in the very wall of the barrel 46. The tongue 47 also comprises a second end 47c projecting from the base 46a of the barrel 46. This second end 47c of the tongue 47 is in particular intended to come into contact with the metal plate 48.

[0048] The tab 47 has in particular a continuous profile so that its first end 47a and its second end 47c are plumb with each other. This continuous profile is particularly advantageous during the manufacture of the tab 47. Indeed, a simple strip of conductive material can be used for example by stamping in a plate. Waste during the manufacture of the tab 47 is thus reduced. In addition, the integration of a tab 47 with a simple strip shape within a mold to be overmolded within the barrel 46 is easy and therefore also limits production costs.

[0049] The length of the second end 47a of the tab 47 may be greater than the distance between its exit point from the base 46a of the barrel 46 and the metal plate 48. The second end 47a of the tab 47 may thus be inclined and exert pressure on the metal plate 48 due to its elasticity in order to ensure good electrical contact.

[0050] Still in order to reduce the disturbances due to electromagnetic radiation, the barrel 46 may also comprise an electrical connector 49 between the stator 20 and the rotor 18, as illustrated in FIGS. 5 to 8. This electrical connector 49 is notably arranged in a housing 51, more particularly in the housing 51 of the end of the internal channel 50 of the barrel 46 opposite the base 46a of said barrel 46.

[0051] This electrical connector 49 can in particular be made of metal, for example by stamping a metal plate.

[0052] The electrical connector 49 more particularly comprises a central part 49a inserted into the housing 51. The housing 51 comprises an internal rim 51a on which the central part 49a rests. This central part 49a is sandwiched and held in the housing 51 by the rolling ring 52.

[0053] The electrical connector 49 comprises at least one leg 49b extending from the central portion 49a. This leg 49b spans the end of the internal channel 50 of the barrel 46 so that its end comes into contact with the stack of sheets 36. The end of the leg 49b may in particular be arranged between the barrel 46 and the stack of sheets 36, more precisely between the annular central portion 36a of the stack of sheets 36 and the barrel 46. The electrical contact between the rotor 18 and the stator 20 is thus made via the stack of sheets 36 and the bearing ring 52 through which the shaft 26 passes.

[0054] A system of notches 49c and lugs 51a between the internal channel 50 and the central part 49a of the electrical connector 49 can be produced. This system of notches 49c and lugs 51a can in particular play a foolproof role during the manufacture of the electric motor 14 and also in order to block the electrical connector 49 and prevent it from rotating around the axis AL. In the example illustrated in FIGS. 5 and 6, the notches 49c are carried by the central part 49a of the electrical connector 49 and the lugs 51a are carried by the internal wall of the internal channel 50.

[0055] The end of the at least one leg 49b may be curved in order to ensure good electrical contact with the stack of sheets 36. The elasticity of the leg 49b also allows good electrical contact with the stack of sheets.

[0056] The central portion 49a of the electrical connector 49 may in particular be annular. In the example illustrated in FIGS. 5 and 6, the electrical connector comprises three legs 49b distributed regularly around the annular central portion 49a. The rolling ring 52 then rests completely on the annular central portion 49a.

[0057] According to a particular embodiment illustrated in [Fig.8], the stator 20 of the electric motor 14 may comprise a screen 58 arranged at the opposite end of the base 46a of the barrel 46 covering the branches 31, 36b and 42b as well as the windings 30. This screen 58 is in particular arranged between the stator 20 and the cup 22 of the rotor 18 without coming into contact with the windings 30.

[0058] The screen 58 is made of a conductive material, for example metal. The screen 58 may more particularly have a disc shape with the axis A1 as its center in the mounted state. This screen makes it possible in particular to limit the electromagnetic radiation emitted by the windings 30 in operation and which may interfere with other electrical or electronic devices.

[0059] The screen 58 may be formed by a metal sheet. The metal sheet may in particular have a thickness of between 0.35 mm and 1 mm, preferably between 0.35 mm and 0.45 mm. The screen 58 may be formed by deformation of a metal sheet, in particular by stamping and perforations, if necessary.

[0060] As illustrated in [Fig.8], the screen 58 and the electrical connector 49 may be made from one material of the other. The screen 58 thus comprises a central recess 58a annular inserting into the housing 51 and ending with the annular central part 49a of the electrical connector 49. This central recess 58a is in particular inserted into the housing 51 of the internal channel 50 of the barrel 46. This central recess 58a is open in order to allow the shaft 26 to pass. The screen 58 comprises at least one radial cutout 58b, starting from the central recess 58a. The at least one leg 49b of the electrical connector 49 is thus formed by this radial cutout 58b within the screen 58. The shape of the at least one leg 49b is given for example during cutting, for example by stamping.

[0061] The fact that the screen 58 and the electrical connector 49 are made of one material from each other makes it possible in particular to fix the screen 58 in the same way as the electrical connector 49 by means of the rolling ring 52 inserted in the housing 51. In addition, the screen 58 is, like the electrical connector 46, also electrically connected to the rotor 18.

[0062] In order also to maintain the screen 58 as well as the electrical connector 46, a system of notches 58c and lugs 51a between the internal channel 50 and the central recess 58a of the screen 58 can be produced. This system of notches 58c and lugs 51a can in particular play a foolproof role during the manufacture of the electric motor 14 and also in order to block the electrical connector 49 and prevent it from rotating around the axis AL. In the example illustrated in [Fig.8], the notches 58c are carried by the central recess 58a of the screen 58 and the lugs 51a are carried by the internal wall of the internal channel 50.

Claims

Claims

1. Stator (20) for an electric motor (14) of a ventilation device (10) for a motor vehicle, said stator (20) comprising: - a barrel (46) comprising a base (46a) fixed on a support (16), and - a stack of metal sheets (36), the barrel (46) comprising an internal channel (50) which passes right through the barrel (46) in the direction of an axis (A1), said internal channel (50) being intended to be passed through by a shaft (26) of a rotor (18), the internal channel (50) comprising at least one housing (51) intended to receive a bearing ring (52), characterized in that the stator (20) further comprises an electrical connector (49) comprising: - a central part (49a) inserted into the at least one housing (51), - at least one leg (49b) starting from the central part (49a) and spanning the end of the internal channel (50) of the barrel (46) so that the end of said leg (49b) comes into contact with the stack of sheets (36).

2. Stator (20) according to the preceding claim, characterized in that the end of the at least one leg (49b) is curved.

3. Stator (20) according to claim 1 or 2, characterized in that the central part (49a) of the electrical connector (49) is annular.

4. Stator (20) according to any one of the preceding claims, characterized in that the at least one housing (51) comprises an internal rim (51a) on which the central part (49a) of the electrical connector (49) rests, said central part (49a) being sandwiched and held in the housing (51) by the rolling ring (52).

5. Stator (20) according to any one of the preceding claims, characterized in that it comprises an electrically conductive screen (58) arranged at the opposite end of the base (46a) of the barrel (46) and covering branches (31, 36b, 42b) of said barrel (46) as well as windings (30) surrounding said branches (31, 36b, 42b), the screen (58) and the electrical connector (49) being made of one material from the other.

6. Stator (20) according to the preceding claim, characterized in that the screen (58) comprises: - an annular central recess (58a) inserted into the at least one housing (51) and ending in the annular central part (49a) of the electrical connector (49), - a radial cutout (58b), starting from the central recess (58a), the at least one leg (49b) of the electrical connector (49) being formed by said radial cutout (58b) within the screen (58).

7. Stator (20) according to the preceding claim, characterized in that it comprises a system of notches (58c) and lugs (51a) between the internal channel (50) and the central recess (58a) of the screen (58).

8. Stator (20) according to any one of the preceding claims, characterized in that the support (16) comprises a metal plate (48) connected to the electrical ground, the stator (20) further comprising an electrically conductive tab (47), said tab (47) comprising: - a first end (47a) projecting from the barrel (46) so as to come into contact with the stack of sheets (36), - an internal part (47b) overmolded in the very wall of the barrel (46), and - a second end (47c) projecting from the base (46a) of the barrel (46) and coming into contact with the metal plate (48), said tab (47) having a continuous profile so that its first end (47a) and its second end (47c) are plumb with each other.

9. Stator (20) according to the preceding claim, characterized in that the length of the second end (47a) of the tab (47) is greater than the distance between its exit point from the base (46a) of the barrel (46) and the metal plate (48).

10. Electric motor (14) of a ventilation device (10) for a motor vehicle comprising a stator (20) according to any one of the preceding claims.

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