ELECTRIC MOTOR FOR MOTOR PROPULSION AND METHOD FOR ASSEMBLING A SEALING DEVICE FOR SUCH A MOTOR

Abstract

The invention relates to an electric motor (1) for the propulsion of a motor vehicle, said motor comprising a housing (2), a sleeve (3) embedded in a recess of said housing, a plurality of coils (6) mounted inside said sleeve and having a projecting portion (7), a sealing device (8) comprising an annular sealing gasket (9) made of elastomer material and a ring (11) made of molded plastic material fitted inside said gasket, said device having a mounting hole (14) through which it fits into said projecting portion, said ring being in two separate semi-circular parts held together by said gasket receiving them in a press fit. The invention also relates to a method for mounting a sealing device (8) of such a motor (1). Figure 1

Description

Title of the invention: ELECTRIC MOTOR FOR AUTOMOBILE PROPULSION AND ASSEMBLY METHOD OF A SEALING DEVICE FOR SUCH AN ENGINE

[0001] The invention relates to an electric motor for the propulsion of a motor vehicle and a method for mounting a sealing device for such a motor.

[0002] It is known to produce an electric motor for the propulsion of a motor vehicle, said motor comprising a casing defining a cylindrical housing, said motor further comprising a rotor, provided with a plurality of permanent magnets, and a stator comprising: - a cylindrical steel sleeve embedded in said housing, said sleeve being provided with axial channels intended to be supplied with pressurized oil, said sleeve having an axial end into which said channels open, - and a plurality of coils of conductive wire intended to be supplied with electric current, said coils being mounted inside said sleeve, said plurality of coils having a projecting portion extending axially from said axial end and forming, in axial view, within a circle, said motor further comprising an annular sealing device having a mounting hole through which it fits said projecting portion, said device comprising: - an annular sealing gasket made of elastomeric material, said gasket taking support against said casing and against said axial end so as to define a circular cavity, said channels opening into said cavity so that said cavity can receive the oil from said channels, - and a molded plastic ring fitted inside said seal, said ring having a plurality of circularly distributed drainage holes positioned opposite a plurality of corresponding drainage holes provided in said seal opposite said cavity and said protruding part, so as to allow evacuation of oil from said cavity to said protruding part for cooling.

[0003] It should be noted here that the cooling of the protruding part allows, by thermal conduction, an overall cooling of the coils.

[0004] With such an arrangement, the assembly of the sealing device can prove complex, the mounting hole having to be temporarily enlarged to allow the fitting of said device onto the protruding part.

[0005] The invention aims to overcome this drawback.

[0006] To this end, and according to a first aspect, the invention proposes an electric motor for the propulsion of a motor vehicle, said motor comprising a casing defining a cylindrical housing, said motor further comprising a rotor, provided with a plurality of permanent magnets, and a stator comprising: - a cylindrical steel sleeve embedded in said housing, said sleeve being provided with axial channels intended to be supplied with pressurized oil, said sleeve having an axial end into which said channels open, - and a plurality of coils of conductive wire intended to be supplied with electric current, said coils being mounted inside said sleeve, said plurality of coils having a projecting part extending axially from said axial end and forming, in axial view, within a circle, said motor further comprising an annular sealing device having a mounting hole through which it fits said protruding part, said device comprising: - an annular sealing gasket made of elastomeric material, said gasket bearing against said casing and against said axial end so as to define a circular cavity, said channels opening into said cavity so that said cavity can receive the oil from said channels, - and a molded plastic ring fitted inside said seal, said ring being provided with a plurality of circularly distributed drainage holes and being positioned opposite a plurality of corresponding drainage holes provided in said seal opposite said cavity and said protruding part, so as to allow the oil to be evacuated from said cavity to said protruding part for cooling purposes, said ring being in two separate semi-circular parts held together one against the other by the said joint receiving them in interlocking, to allow a temporary enlargement of the said mounting orifice, by separating the said parts from each other, in order to ensure the assembly of the said sealing device.

[0007] It is specified here that, throughout the description, the term "axially" is taken in reference to the axis of rotation of the motor (reference X on the figures), corresponding in this case to the axis of symmetry of the sleeve.

[0008] The elastic nature of the seal allows it to stretch during the assembly of the sealing device and then, after retraction, to ensure the maintenance of said device once assembled.

[0009] Furthermore, the use of a ring in two separate parts eliminates the need to deform it during the assembly of the sealing device, which is an advantage. when the plastic material constituting said ring is not very flexible, which is usually the case with plastic materials intended to be exposed to the high temperatures found in engines.

[0010] According to one embodiment, the ends of the ring parts are arranged so that two contiguous ends fit together when the ring is in the unexpanded configuration, so as to allow good positioning of said parts relative to each other.

[0011] According to one embodiment, the sealing gasket is made of rubber.

[0012] According to one embodiment, the ring is made of glass fiber reinforced polyamide, the choice of such plastic material allowing said ring to exhibit good resistance to high temperatures, for example on the order of 200°C.

[0013] According to one embodiment, the drainage orifices are distributed circularly in a regular manner, so as to ensure homogeneous cooling of the protruding part.

[0014] According to one embodiment, the number of drainage ports is between 6 and 20, so as to ensure homogeneous cooling of the protruding part.

[0015] According to a second aspect, the invention proposes a method for mounting a sealing device for such a motor, said motor comprising a stator comprising a plurality of coils having a protruding part, said device comprising an annular sealing gasket based on elastomer material and a ring made of molded plastic material fitted inside said gasket, said device having a mounting hole, said ring being in two disjointed semi-circular parts held against each other by said gasket receiving them by fitting them together, said method comprising the following steps: - deforming said device under stress so as to change it from a nominal configuration, where said seal is unstretched and where said parts are held against each other, to an assembly configuration where said seal is stretched and where said parts are separated from each other in order to enlarge said mounting orifice, - to fit said protruding part with said device when placed in the mounting configuration, - to release the constraint in such a way as to achieve, under the effect of an elastic release of said joint, the assembly and retention of said device.

[0016] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: [Fig. 1] is a partial schematic axial cross-sectional representation of a motor according to one embodiment, [Fig.2] is a schematic exploded perspective representation of the device sealing of the motor represented in [Fig.1], the ring of said device being represented with its parts separated from each other.

[0017] An electric motor 1 for the propulsion of a motor vehicle is now described with reference to the figures, said motor comprising a casing 2 defining a cylindrical housing, said motor further comprising a rotor, not shown, provided with a plurality of permanent magnets, and a stator comprising: - a cylindrical steel sleeve 3 embedded in said housing, said sleeve being provided with axial channels 4 intended to be supplied with pressurized oil, said sleeve having an axial end 5 into which said channels open, - and a plurality of coils 6 of conductive wire intended to be supplied with electric current, said coils being mounted inside said sleeve, said plurality of coils having a protruding part 7 extending axially from said axial end and forming, in axial view, within a circle, said motor further comprising an annular sealing device 8 having a mounting hole 14 through which it fits said protruding part, said device comprising: - an annular sealing gasket 9 made of elastomeric material, said gasket bearing against said casing and against said axial end so as to define a circular cavity 10, said channels opening into said cavity so that said cavity can receive the oil from said channels, - and a molded plastic ring 11 fitted inside said seal, said ring being provided with a plurality of circularly distributed drainage orifices 12 and positioned opposite a plurality of corresponding drainage orifices 13 provided in said seal opposite said cavity and said protruding part, so as to allow the oil to be evacuated from said cavity to said protruding part for cooling purposes, said ring consisting of two semi-circular, disjointed parts 11a, 11b held together by said gasket receiving them in a fit, to allow temporary enlargement of said mounting orifice by separating said parts from each other, in order to ensure the mounting of said sealing device.

[0018] As illustrated, the two parts 1a, 11b are separated from each other by two openings 24.

[0019] According to the embodiment shown, the ends 15 of the parts 1 la,l 1b of the ring are arranged so that two contiguous ends 15 fit into each other when the ring 11 is in the unexpanded configuration.

[0020]

[0021]

[0022]

[0023]

[0024] According to one design, the sealing gasket 9 is made of rubber. According to one embodiment, ring 11 is made of polyamide reinforced with glass fibers. According to an embodiment not shown, the evacuation orifices 12 are distributed circularly in a regular manner. According to an implementation not shown, the number of drainage ports 12 is between 6 and 20. Finally, a method for mounting a sealing device 8 of such a motor 1 is described, said motor comprising a stator comprising a plurality of coils 6 having a protruding part 7, said device comprising an annular sealing gasket 9 based on elastomeric material and a ring 11 of molded plastic material fitted inside said gasket, said device having a mounting hole 14, said ring being in two disjointed semi-circular parts 1a,l 1b held against each other by said gasket receiving them in a fitting, said method comprising the following steps: - deforming said device under stress so as to change it from a nominal configuration, where said seal is unstretched and where said parts are held against each other, to an assembly configuration where said seal is stretched and where said parts are separated from each other in order to enlarge said mounting orifice, - to fit said protruding part with said device when placed in the mounting configuration, - to release the constraint in such a way as to achieve, under the effect of an elastic release of said joint, the assembly and retention of said device.

Claims

Claims

1. Electric motor (1) for propelling a motor vehicle, said motor comprising a casing (2) defining a cylindrical housing, said motor further comprising a rotor, provided with a plurality of permanent magnets, and a stator comprising: - a cylindrical steel sleeve (3) embedded in said housing, said sleeve being provided with axial channels (4) intended to be supplied with pressurized oil, said sleeve having an axial end (5) where said channels open, - and a plurality of coils (6) of conductive wire intended to be supplied with electric current, said coils being mounted inside said sleeve, said plurality of coils having a projecting part (7) axially extending beyond said axial end and falling in axial view within a circle, said motor further comprising an annular sealing device (8) having a mounting orifice (14) through which it fits said projecting part, said device comprising: - an annular sealing gasket (9) based on elastomer material, said gasket bearing against said casing and against said axial end so as to define a circular cavity (10), said channels opening into said cavity so that said cavity can receive the oil coming from said channels, - and a ring (11) made of molded plastic material fitted inside said seal, said ring being provided with a plurality of discharge orifices (12) distributed circularly and being positioned opposite a plurality of corresponding discharge orifices (13) provided in said seal opposite said cavity and said projecting part, so as to allow evacuation of the oil from said cavity towards said projecting part to carry out its cooling, said motor being characterized in that said ring is presented in two disjointed semi-circular parts (11a, 11b) held against each other by said seal receiving them in an interlocking manner, to allow a temporary enlargement of said mounting orifice, by spacing said parts apart from each other, in order to ensure the mounting of said sealing device.

2. Motor (1) according to claim 1, characterized in that the ends (15) of the ring parts (11a, 11b) are arranged so that two contiguous ends (15) fit into each other when the ring (11) is in the non-expanded configuration.

3. Motor (1) according to any one of claims 1 or 2, characterized in that the sealing gasket (9) is made of rubber.

4. Motor (1) according to any one of claims 1 to 3, characterized in that the ring (11) is made of polyamide reinforced with glass fibers.

5. Motor (1) according to any one of claims 1 to 4, characterized in that the discharge orifices (12) are distributed circularly in a regular manner.

6. Motor (1) according to any one of claims 1 to 5, characterized in that the number of discharge orifices (12) is between 6 and 20.

7. A method of mounting a sealing device (8) of a motor (1) according to any one of claims 1 to 6, said motor comprising a stator comprising a plurality of coils (6) having a projecting portion (7), said device comprising an annular sealing gasket (9) based on elastomeric material and a ring (11) made of molded plastic material fitted inside said gasket, said device having a mounting orifice (14), said ring being in two separate semi-circular parts (11a, 11b) held against each other by said gasket receiving them in fitting, said method comprising the following steps: - deforming said device under stress so as to make it pass from a nominal configuration, where said gasket is unstretched and where said parts are held against each other,to a mounting configuration where said seal is stretched and said parts are moved apart from each other in order to enlarge said mounting hole, - fitting said protruding part by said confi- device, assembly diagram, release the constraint so as to achieve, under the effect of an elastic release of said joint, the assembly and maintenance of said device.

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