Closing cover for an electric powertrain and electric powertrain including a closing cover.

Abstract

The invention relates to a cover (10) for an electric powertrain, said cover comprising a mounting frame (11), a cover plate (13) and a suspension pin (20) disposed on the outer face (15) of the cover plate (13), the suspension pin (20) comprising on its free end (21) a bearing area (22) arranged to receive an elastomer element (3). Figure for the abstract: Fig. 2

Description

Title of the invention: Closing hood for an electric powertrain and electric powertrain comprising a closing hood. Technical field

[0001] The invention relates to the field of electric powertrains for motorized vehicles and more particularly to one of the components of this powertrain which is the closing hood. This type of powertrain generally comprises a reversible electric machine and a speed reducer connecting said electric machine to the wheels of the vehicle.

[0002] Due to the excitations of the speed reducer and the reversible electric machine, the structural elements of a powertrain, more particularly the external surfaces, can vibrate in their own mode and propagate noise towards the inside or outside of the motorized vehicle, for example a motor vehicle or an industrial vehicle. For example, when a transmission casing closing cover has vibration modes with natural frequencies close to the excitation frequencies, the noise levels are amplified.

[0003] To combat vibrations, it is known to equip powertrains with suspension mounts arranged in particular between the casing of the electric machine and the chassis of the vehicle. The suspension mounts are generally installed on the most rigid parts of the casing. However, they are only effective against vibrations within a limited frequency range. In addition, the space available around the powertrain is limited, which makes it difficult to install this type of suspension mount.

[0004] An electric powertrain as described in German patent application DE 102021214776 A1 comprises a reversible electric machine and a speed reducer integrated within a transmission casing. In order to control the electric machine, an electric current inverter integrates electronic components for managing the electrical power according to the needs of the vehicle. The electronic components of the inverter are supported by the transmission casing and protected by a closing cover attached and fixed to the transmission casing. The closing cover comprises in particular a rigid fixing perimeter and a thin wall which can vibrate under the effect of its natural frequency. The noise generated by the vibrations of the electric machine and the speed reducer is transmitted through the surface of the closing cover.

[0005] The objective of the invention is to treat the vibrations generated by the hood of closure whose natural frequency is generally greater than 200Hz. By extension, the objective of the invention is to treat the vibrations generated by all the structural elements of a powertrain.

[0006] The present invention also aims to provide a vibration reduction solution for the electric powertrain, the installation of which would be facilitated within the motorized vehicle.

[0007] According to a first aspect, the invention relates to a closing cover for an electric powertrain, in particular arranged to close a sealed cavity of said electric powertrain, said closing cover comprising a fixing perimeter, a closing wall and a suspension pad connected to the closing wall, the suspension pad comprising on one of its ends a support zone arranged to receive an elastomer element.

[0008] The integration of the suspension stud directly into the closing hood makes it possible to cancel the low-frequency excitation modes linked to thin hoods obtained by molding or stamping and limits the acoustic radiation of the electric powertrain. In addition, the integration of the suspension stud directly into the closing hood does not impact the overall size of the electric powertrain.

[0009] Advantageously, the suspension pad comprises a drilling-tapping along a secondary axis X2 opening into the support zone.

[0010] Preferably, the support zone is arranged on the free end of the suspension pad which is furthest from the fixing perimeter.

[0011] The invention may have one or other of the characteristics described below combined with each other or taken independently of each other: - the closing hood comprises at least one stiffening rib connecting the suspension stud to the closing wall.

[0012] - the suspension stud is a cylindrical sleeve machined from steel attached to the closing wall, one end of the cylindrical sleeve forms the support zone.

[0013] - the fixing perimeter comprises a flat interface zone with the motorcycle group electric thruster, the support zone is parallel to the flat interface zone.

[0014] - the fixing perimeter comprises a flat interface zone with the motorcycle group electric thruster, the support zone is perpendicular to the flat interface zone.

[0015] - the planar interface area comprises an insertion groove for a seal sealing.

[0016] - the fixing perimeter comprises a flat interface zone with the motorcycle group electric thruster, the support zone is inclined relative to the flat interface zone at an angle between 1° and 89°.

[0017] - the suspension stud is connected to the external face of the closing wall.

[0018] - the suspension stud is connected to the internal face of the closing wall.

[0019] - the support zone is cylindrical in shape along a secondary axis of revolution X2 oriented perpendicular to the closing wall.

[0020] - the suspension pad comprises a base fused with the closing wall.

[0021] - the area of ​​the fusion surface of the base is greater than one eighth of the surface area of ​​the external face of the closing wall.

[0022] - the surface area of ​​the fusion surface of the base is greater than 3 times the surface area of the section of the cylindrical support zone measured perpendicular to the secondary axis X2.

[0023] - the cylindrical support zone is oriented perpendicular to the closing wall along a secondary axis X2.

[0024] - the fusion surface is composed of a plurality of surfaces distributed around the secondary axis X2 and the secondary axis X2 passes through one of the fusion surfaces of the base.

[0025] - the fusion surface is composed of a plurality of surfaces distributed around the secondary axis X2 and the secondary axis X2 does not cross the fusion surface of the base.

[0026] - the closing hood comprises a plurality of stiffening ribs distributed around the secondary axis X2.

[0027] - stiffening ribs extend from the fusion surface of the base in direction of the free end of the suspension stud.

[0028] - the fusion surface is crossed by the secondary axis X2 and forms a single and single surface.

[0029] - the fusion surface is composed of a plurality of surfaces distributed around the secondary axis X2.

[0030] - the secondary axis X2 does not cross the fusion surface of the base.

[0031] - stiffening ribs extend from the inner face of the wall of closing towards the fixing perimeter.

[0032] - stiffening stampings are formed on the closing wall and penetrate into direction of the suspension block, the inner surface of the stiffening stampings serving as the centering surface of the suspension block.

[0033] - the surface area of ​​the fusion surface of the base is greater than a quarter of the su perficie of the external face of the closing wall.

[0034] - the suspension stud is attached to the closing wall.

[0035] - the suspension stud is made of material with the fixing perimeter and the wall of closing.

[0036] - the secondary axis X2 of the suspension stud passes substantially through the center of gravity of said closing hood.

[0037] - the suspension pad is obtained from casting with the closing wall.

[0038] - the suspension stud is obtained by stamping the closing wall.

[0039] - the suspension stud includes stiffening stampings.

[0040] - the closing hood is obtained by mechanical welding.

[0041] - the closing hood is obtained by casting.

[0042] The suspension pad thus connected to the closing wall has the advantage of stiffening the closing cover. This makes it possible to cancel the low-frequency excitation modes linked to the thin covers obtained by molding or stamping and limits the acoustic radiation of the electric powertrain.

[0043] The invention applies for example to the closing hood made of stamped sheet metal whose thickness can be between 0.5 mm and 3 mm.

[0044] The invention applies for example to the closing hood made from cast aluminum, the variable thickness of which can be between 2 mm and 10 mm.

[0045] According to a second aspect, the invention also relates to an electric powertrain for a motorized vehicle comprising:

[0046] - a reversible electrical machine comprising a rotor having an output shaft mobile in rotation around a machine axis X;

[0047] - an electric current inverter supplying the electric machine;

[0048] - a speed reducer kinematically linked to the rotor of the electric machine re reversible

[0049] - a transmission casing at least partially supporting the electric machine reversible and / or inverter and / or speed reducer;

[0050] - a closing hood incorporating all or part of the characteristics mentioned above previously, reported on a cavity formed on one of the elements of the electric powertrain chosen from the reversible electric machine, the inverter, the speed reducer or the transmission casing.

[0051] The closing cover may, for example, be attached to an inverter of the electric powertrain. Thus, when the inverter is mounted on the electric machine, it contributes to reducing the acoustic radiation of the electric powertrain. The same applies when the closing cover is attached to a cavity of the speed reducer or the reversible electric machine.

[0052] The electric powertrain may include one or more of the following features:

[0053] - the fixing perimeter of the closing cover rests on the element of the group electric powertrain that includes the cavity.

[0054] - the closing wall of the closing hood comprises an internal face arranged in look of the cavity.

[0055] - the fixing perimeter of the closing cover rests on the element of the group electric powertrain that includes the cavity.

[0056] - the cavity comprises a support spacer, a hood stiffening rib closing piece bearing on said support spacer.

[0057] - the closing hood is fixed on the element of the electric powertrain which includes the cavity using fixing screws.

[0058] - the closing hood supports an elastomer element arranged on the area support of the suspension pad.

[0059] - the closing wall is axially interposed between the elastomer element and the suspension pad.

[0060] - a fixing screw is inserted into a bore of the elastomer element and screwed in a drilling-tapping of the suspension stud.

[0061] - according to a variant of the invention, the secondary axis X2 is parallel to the axis of X machine.

[0062] - according to another variant of the invention, the secondary axis X2 is perpendicular to the X machine axis.

[0063] Advantageously, the integration of the suspension stud directly into the closing hood does not impact the overall size of the electric powertrain. Brief description of the figures

[0064] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the appended drawings.

[0065] [Fig-1] [Fig.l] represents an electric powertrain comprising a closing hood according to a first embodiment of the invention.

[0066] [Fig.2] [Fig.2] represents a closing hood according to a second embodiment of the invention.

[0067] [Fig.3] [Fig.3] represents another electric powertrain comprising a closing hood according to a third embodiment of the invention.

[0068] [Fig.4] [Fig.4] illustrates an axial section of the closing hood according to the third embodiment of the invention.

[0069] [Fig.5] [Fig.5] illustrates an axial section of the closing hood according to a fourth embodiment of the invention. Description of the embodiments

[0070] [Fig.l] illustrates an electric powertrain 1 for a motorized vehicle according to a first embodiment of the invention, comprising a reversible electric machine 30 comprising a stator (not shown), a rotor 31 movable in rotation around a machine axis X, an inverter 50 of electric current supplying the electric machine and a speed reducer 40 kinematically linked to the rotor 31 of the reversible electric machine. The output shaft of the speed reducer drives a set of one or more drive wheels of the motorized vehicle, in this case a motor vehicle.

[0071] The speed reducer 40 housed inside a cavity of the transmission casing comprises transmission shafts to which toothed wheels are rotationally secured to achieve a speed reduction ratio between the rotor of the electrical machine and the output shaft of the speed reducer. The speed reducer is itself protected from the external environment by a closing cover.

[0072] The reversible electric machine, the speed reducer and the inverter are supported by a transmission casing. The electric powertrain 1 is fixed to the chassis of the vehicle by means of supports 4 having a damping function. Each support 4 fixed to the chassis comprises a cylindrical elastomer element 3 into which a suspension stud 20 attached to the electric powertrain is inserted.

[0073] According to the invention, the suspension stud 20 can be integrated into any type of closing cover mentioned in this description and used to close a cavity of the electric powertrain 1. The fusion of the shapes of the suspension stud with that of the closing cover contributes to the stiffening of said closing cover.

[0074] In the first embodiment of the invention, the cavity of the transmission casing is closed by a closing cover 10 comprising a fixing perimeter 11, a closing wall 13 and a suspension stud 20 arranged on the external face 15 of the closing wall 13. The fixing perimeter 11 rests on a complementary perimeter arranged on the transmission casing. In particular, the fixing perimeter 11 of the closing cover bears on the element of the electric powertrain which comprises the cavity. In addition, a seal is arranged between the two fixing perimeters. The fixing by fixing screw of the closing cover, the crushing of the seal and the assembly of the fixing perimeter 11 on the transmission casing makes it possible to guarantee a seal of the powertrain in this zone.

[0075] As illustrated in [Fig.l], the suspension pad 20 also comprises on its free end 21 a cylindrical support zone 22 which is inserted into the elastomer element 3. The cylindrical support zone 22 of the suspension pad 20 is oriented perpendicular to the closing wall 13 along a secondary axis X2. The secondary axis X2 is parallel to the machine axis X.

[0076] The suspension pad 20 comprises a base 23 fused with the closing wall, the surface area of ​​the fusion surface of the base 23 is greater than a eighth of the surface area of ​​the external face of the closing wall. To achieve this favorable ratio, the suspension pad 20 is obtained by casting with the closing wall 13. The fusion surface is crossed by the secondary axis X2 and forms a single surface.

[0077] The suspension pad 20 comprises a base 23 fused with the closing wall, the surface area of ​​the fusion surface of the base 23 is greater than 3 times the surface area of ​​the section of the cylindrical support zone measured perpendicular to the secondary axis X2.

[0078] In [Fig.2] a second embodiment of the invention is shown diagrammatically, which differs from the first embodiment in that the closing cover 10 is obtained by mechanical welding.

[0079] In this second embodiment, the cavity 5 of the transmission casing 45 is closed by a closing cover 10 comprising a fixing perimeter 11, a closing wall 13 and a suspension stud 20 arranged on the external face 15 of the closing wall 13. The closing cover 10 is fixed to the transmission casing 45 using fixing screws.

[0080] The suspension pad 20 comprises on its free end 21 a cylindrical support zone 22 which is inserted into the elastomer element 3. The cylindrical support zone 22 of the suspension pad 20 is oriented perpendicular to the closing wall 13 along a secondary axis X2.

[0081] The suspension pad 20 comprises a base 23 fused with the closing wall. The closing wall 13 and the base 23 are fused at a first plane PL. The surface area of ​​the fusion surface of the base 23 is greater than 3 times the surface area of ​​the section of the cylindrical support zone measured perpendicular to the secondary axis X2. The measurement is made according to the geometric plane P2 which is perpendicular to the secondary axis X2.

[0082] Stiffening ribs 25 extend from the fusion surface of the base 23 towards the free end 21 of the suspension stud 20. The stiffening ribs are here welded to the closing wall 13 and to the suspension stud 20. The fusion surface is composed of a plurality of surfaces distributed around the secondary axis X2 and the secondary axis X2 does not cross the fusion surface of the base. The fusion surface passes through the geometric plane PI illustrated in [Fig.2].

[0083] The stiffening ribs 25 are oriented perpendicular to the closing wall. At least one of the stiffening ribs is oriented vertically in order to absorb the force linked to the action of gravity.

[0084] This second embodiment combines rigidity and reduced weight for the closing hood.

[0085] In Figures 3 and 4 is illustrated a third embodiment of the invention which differs from the first embodiment in that the closing cover 10 is obtained partly by stamping.

[0086] In this third embodiment, the electric powertrain 1 comprises a reversible electric machine 30 comprising a stator (not shown), a rotor 31 rotatable about a machine axis X, an inverter 50 of electric current supplying the electric machine and a speed reducer 40 kinematically linked to the rotor 31 of the reversible electric machine. The output shaft of the speed reducer drives a set of one or more drive wheels of the motorized vehicle, in this case a motor vehicle.

[0087] The reversible electric machine, the speed reducer and the inverter are supported by a transmission casing. The electric powertrain 1 is fixed to the chassis of the vehicle by means of supports 4 having a damping function. Each support 4 fixed to the chassis comprises a cylindrical elastomer element 3 fixed to the closing hood 10 by means of the suspension stud 20.

[0088] More precisely, the cavity 5 of the inverter 50 is closed by a closing cover 10 comprising a fixing perimeter 11, a closing wall 13 and a suspension stud 20 arranged on the internal face 16 of the closing wall 13. The closing cover is fixed to the inverter using fixing screws. The closing cover 10 protects at least one electronic card contained in the cavity 5 of the inverter 50.

[0089] The suspension stud 20 comprises on its free end 21 a support zone 22 which is inserted into an orifice 13a of the closing wall 13. The closing cover 10 supports the elastomer element 3 attached to the support zone 22 of the suspension stud 20. In this embodiment, the suspension stud 20 is a cylindrical sleeve machined from steel attached to the closing wall and one of the ends of the cylindrical sleeve forms the support zone.

[0090] The fixing perimeter 11 comprises a flat interface zone 11a with the electric powertrain, the support zone 22 is parallel to this flat interface zone. The support zone 22 is arranged on the free end 21 of the suspension pad furthest from the fixing perimeter 11.

[0091] The suspension pad comprises a drilling-tapping 27 along a secondary axis X2 opening into the support zone 22. A fixing screw 28 is inserted into a bore of the elastomer element 3 and screwed into a drilling-tapping 27 of the suspension pad. The closing wall 13 is axially interposed between the elastomer element 3 and the suspension pad 20.

[0092] In this embodiment, the suspension stud is a machined part attached to the internal face 16. The closing cover is made of two pieces assembled by riveting. Alternatively, the two pieces can be welded, screwed or crimped.

[0093] Stiffening stampings 24 are formed on the closing wall 13 and penetrate towards the suspension pad 20. To improve the rigidity of this stamped solution, the internal face of the stiffening stampings 24 serve as a centering surface for the suspension pad 20. At least three stiffening stampings 24 will be produced, distributed angularly around the secondary axis X2 to perform this function of centering and taking up mechanical forces within the suspension pad.

[0094] The closing hood 10 has a substantially symmetrical shape such that the secondary axis X2 of the suspension stud passes substantially through the center of gravity G of said closing hood. The secondary axis X2 is perpendicular to the machine axis X.

[0095] In [Fig. 5] a fourth embodiment of the invention is illustrated which differs from the third embodiment in that the closing cap 10 is obtained by casting so that the suspension stud 20 is made in one piece with the fixing perimeter 11 and the closing wall 13.

[0096] In this fourth embodiment, the cavity 5 of the inverter 50 is closed by a closing cover 10 comprising a fixing perimeter 11, a closing wall 13 and a suspension stud 20 fused directly with the closing wall 13. The fixing perimeter 11 comprises a flat interface zone 11a with the electric powertrain, the support zone 22 is perpendicular to this flat interface zone. The support zone 22 is arranged on the free end 21 of the suspension stud furthest from the fixing perimeter 11. The closing cover 10 is fixed to the element of the electric powertrain which comprises the cavity 5 using fixing screws 8. The closing cover 10 protects an electronic card 9 contained in the cavity 5 of the inverter 50.

[0097] The suspension stud 20 comprises a drilling-tapping 27 along a secondary axis X2 opening into the support zone 22. A fixing screw 28 is inserted into a bore of the elastomer element 3 and screwed into a drilling-tapping 27 of the suspension stud. A stiffening rib 25 connects the suspension stud 20 to the closing wall 13.

[0098] Other stiffening ribs 25 extend from the internal face 16 of the closing wall 13 towards the fixing periphery 11. To improve the stiffening of the closing cover, the cavity 5 comprises a support spacer 6 and one of the stiffening ribs 25 of the closing cover bears on said support spacer 6. A passage hole is formed in the electronic card 9 to allow the support spacer 6 to pass through.

[0099] Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention, as defined by the claims.

[0100] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims

1. Closing cover (10) for an electric powertrain, in particular arranged to close a sealed cavity of said electric powertrain, said closing cover comprising a fixing perimeter (11), a closing wall (13) and a suspension pad (20) connected to the closing wall (13), the suspension pad (20) comprising on one of its ends (21) a support zone (22) arranged to receive an elastomer element.

2. Closing hood (10) according to claim 1, in which the suspension stud (20) comprises a drilling-tapping along a secondary axis (X2) opening into the support zone (22).

3. Closing hood (10) according to claim 1 or 2, comprising at least one stiffening rib (25) connecting the suspension stud (20) to the closing wall (13).

4. Closing hood (10) according to one of the preceding claims, in which the suspension stud (20) is a cylindrical sleeve machined from steel attached to the closing wall (13), one of the ends of the cylindrical sleeve forms the support zone.

5. Closing hood (10) according to one of the preceding claims, in which the fixing periphery (11) comprises a flat interface zone (11a) with the electric powertrain, the support zone (22) is parallel to the flat interface zone (11a).

6. Closing hood (10) according to one of claims 1 to 4, in which the fixing periphery (11) comprises a flat interface zone (11a) with the electric powertrain, the support zone (22) is perpendicular to the flat interface zone (11a).

7. Closing hood (10) according to claim 1, in which stiffening ribs (25) extend from the fusion surface of the base (23) towards the free end (21) of the suspension stud.

8. Closing hood (10) according to one of the preceding claims, in which stiffening ribs (25) extend from the inner face (16) of the closing wall (13) towards the fixing circumference (11).

9. Closing hood (10) according to one of the preceding claims, in which stiffening stampings (24) are formed on the closing wall (13) and penetrate in the direction of the suspension stud (20), the inner surface of the stiffening stampings serving as a centering surface for the suspension stud (20).

10. Closing hood (10) according to one of the preceding claims, in which the suspension stud (20) is attached to the closing wall (13).

11. Closing hood (10) according to one of claims 1 to 9, in which the suspension stud (20) is made in one piece with the fixing circumference (11) and the closing wall (13).

12. Closing hood (10) according to claim 1, in which the support zone (22) is cylindrical in shape along a secondary axis of revolution (X2) oriented perpendicular to the closing wall (13).

13. Electric powertrain (1) for a motorized vehicle comprising: - a reversible electric machine (30) comprising a rotor (31) rotatable about a machine axis (X); - an electric current inverter (50) supplying the electric machine; - a speed reducer (40) kinematically linked to the rotor (31) of the reversible electric machine - a transmission casing (45) at least partially supporting the reversible electric machine and / or the inverter and / or the speed reducer; - a closing cover (10) according to one of the preceding claims, attached to a cavity (5) formed on one of the elements of the electric powertrain chosen from the reversible electric machine, the inverter, the speed reducer or the transmission casing.

14. Electric powertrain (1) according to the preceding claim, in which the closing cover (10) supports an elastomer element (3) arranged on the support zone (22) of the suspension pad (20).

15. Electric powertrain (1) according to claim 13 or 14, wherein the cavity (5) comprises a support spacer (6), a stiffening rib (25) of the closing cover (10) bearing on said support spacer.

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