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 closing wall (13) and a suspension stud (20) disposed on the outer face (15) of the closing wall (13), the suspension stud (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 cover for an electric powertrain and electric powertrain comprising a closing cover. technical field

[0001] The invention relates to the field of electric powertrains for motor vehicles and more particularly to one of the components of this powertrain, namely the closing cover. 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, particularly the external surfaces, can vibrate in their own mode and propagate noise into or out of the motor vehicle, for example, a passenger car or an industrial vehicle. For example, when a transmission housing cover exhibits vibrational 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 positioned, in particular, between the electric motor housing and the vehicle chassis. The suspension mounts are generally located on the most rigid parts of the housing. However, they are only effective against vibrations within a limited frequency range. Furthermore, the available space around the powertrain is limited, making the installation of this type of suspension mount difficult.

[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 housing. To control the electric machine, an electric current inverter incorporates electronic components that manage the electrical power according to the vehicle's needs. The inverter's electronic components are supported by the transmission housing and protected by a cover attached to and fixed to the transmission housing. The cover includes, in particular, a rigid mounting rim and a thin wall that can vibrate at its natural frequency. The noise generated by the vibrations of the electric machine and the speed reducer is transmitted through the surface of the cover.

[0005] The objective of the invention is to treat the vibrations generated by the closing hood, the natural frequency of which is generally greater than 200 Hz. 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 motor 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 stud connected to the closing wall, the suspension stud comprising on one of its ends a support area arranged to receive an elastomer element.

[0008] Integrating the suspension mount directly into the cover eliminates low-frequency excitation modes associated with thin covers produced by molding or stamping and limits the acoustic radiation of the electric powertrain. Furthermore, integrating the suspension mount directly into the cover does not affect the overall dimensions of the electric powertrain.

[0009] Advantageously, the suspension block includes a drilling-tapping along a secondary axis X2 opening into the support area.

[0010] Preferably, the support area is located on the free end of the suspension block that is furthest from the fixing perimeter.

[0011] The invention may have one or more of the features described below, either combined or taken independently of each other: - the closing cover includes at least one stiffening rib connecting the suspension block to the closing wall.

[0012] - the suspension mount is a cylindrical sleeve machined from steel and attached to the closure wall, one end of the cylindrical sleeve forms the support area.

[0013] - the fixing perimeter includes a flat interface area with the group electric powertrain, the support area is parallel to the flat interface area.

[0014] - the fixing perimeter includes a flat interface area with the group electric powertrain, the support area is perpendicular to the flat interface area.

[0015] - the flat interface area includes an insertion groove for a seal sealing.

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

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

[0018] - the suspension block is connected to the inner face of the closing wall.

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

[0020] - the suspension block includes a base fused with the closing wall.

[0021] - the surface area of ​​the base's melting surface is greater than one-eighth of the surface area of ​​the outer face of the closing wall.

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

[0023] - the cylindrical support area is oriented perpendicularly 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 crosses 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 distributed stiffening ribs 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 block.

[0028] - the fusion surface is traversed by the secondary axis X2 and forms a single and unique 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 closure towards the perimeter of the fixing.

[0032] - stiffening indentations are formed on the closing wall and penetrate towards the suspension block, the inner surface of the stiffening stampings serves as the centering surface for the suspension block.

[0033] - the surface area of ​​the base's melting surface is greater than one quarter of the surface area of ​​the outer face of the closing wall.

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

[0035] - the suspension block 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 severity of said closing cover.

[0037] - the suspension block is obtained by casting with the closing wall.

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

[0039] - the suspension mount includes stiffening stampings.

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

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

[0042] The suspension mount 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 associated with 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 cover 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 of cast aluminum whose variable thickness can be between 2 mm and 10 mm.

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

[0046] - a reversible electric machine comprising a rotor having an output shaft mobile rotating around an axis of machine X;

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

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

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

[0050] - a closing cover incorporating all or part of the aforementioned characteristics previously reported on a cavity formed on one of the elements of the electric powertrain selected from the reversible electric machine, the inverter, the speed reducer or the transmission housing.

[0051] The cover can, 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 is true when the 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 motor drive which includes the cavity.

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

[0055] - the fixing perimeter of the closing cover rests on the element of the group electric motor drive which includes the cavity.

[0056] - the cavity includes a support spacer, a hood stiffening rib of closure coming to rest on said support spacer.

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

[0058] - the closing cover supports an elastomer element disposed on the area support for the suspension block.

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

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

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

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

[0063] Advantageously, integrating the suspension mount 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 objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

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

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

[0070] Figure 1 illustrates an electric powertrain 1 for a motorized vehicle according to a first embodiment of the invention, comprising a reversible electric machine 30 including a stator (not shown), a rotor 31 rotating about a machine axis X, an electric current inverter 50 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 one or more drive wheels of the motorized vehicle, in this case a motor vehicle.

[0071] The speed reducer 40, housed within a cavity in the transmission casing, comprises transmission shafts to which gears are rotationally attached, enabling a speed reduction ratio between the rotor of the electric machine and the output shaft of the speed reducer. The speed reducer itself is 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 housing. The electric drive unit 1 is attached to the vehicle chassis by means of supports 4 having a damping function. Each support 4 attached to the chassis includes a cylindrical elastomer element 3 into which a suspension mount 20 attached to the electric drive unit is inserted.

[0073] According to the invention, the suspension block 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 block with that of the closing cover contributes to the rigidification of said closing cover.

[0074] In the first embodiment of the invention, the cavity of the transmission housing is closed by a cover 10 comprising a mounting flange 11, a closing wall 13, and a suspension pin 20 disposed on the outer face 15 of the closing wall 13. The mounting flange 11 rests on a complementary flange formed on the transmission housing. In particular, the mounting flange 11 of the cover bears against the element of the electric powertrain that includes the cavity. In addition, a sealing gasket is disposed between the two mounting flanges. The fastening of the cover by screws, the compression of the sealing gasket, and the assembly of the mounting flange 11 onto the transmission housing ensure the sealing of the powertrain in this area.

[0075] As illustrated in [Fig. 1], the suspension pad 20 also includes on its free end 21 a cylindrical bearing area 22 which is inserted into the elastomer element 3. The cylindrical bearing area 22 of the suspension pad 20 is oriented perpendicularly 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 one-eighth of the surface area of ​​the outer face of the closing wall. To achieve this favorable ratio, the suspension pad 20 is cast with the closing wall 13. The fusion surface is traversed by the secondary axis X2 and forms a single, continuous surface.

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

[0078] Figure 2 shows a schematic representation of a second embodiment of the invention 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 housing 45 is closed by a closing cover 10 comprising a fixing rim 11, a closing wall 13 and a suspension stud 20 disposed on the external face 15 of the closing wall 13. The closing cover 10 is fixed to the transmission housing 45 by means of fixing screws.

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

[0081] The suspension mount 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 area of ​​the cross-section of the cylindrical bearing zone measured perpendicular to the secondary axis X2. The measurement is taken along 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 pad 20. The stiffening ribs are welded to the closing wall 13 and to the suspension pad 20. The fusion surface is composed of a plurality of surfaces distributed around the axis The secondary X2 axis does not cross the base's fusion surface. The fusion surface passes through the geometric plane PI illustrated in [Fig.2].

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

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

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

[0086] In this third embodiment, the electric powertrain 1 comprises a reversible electric machine 30 including a stator (not shown), a rotor 31 rotating about a machine axis X, an electric current inverter 50 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 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 housing. The electric drive unit 1 is attached to the vehicle chassis by means of supports 4 having a damping function. Each support 4 attached to the chassis includes a cylindrical elastomer element 3 fixed to the closing cover 10 by means of the suspension mount 20.

[0088] More specifically, the cavity 5 of the inverter 50 is closed by a cover 10 comprising a mounting rim 11, a closing wall 13, and a suspension pin 20 disposed on the inner face 16 of the closing wall 13. The cover is fixed to the inverter by means of fixing screws. The cover 10 protects at least one electronic circuit board contained in the cavity 5 of the inverter 50.

[0089] The suspension pad 20 includes on its free end 21 a bearing area 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 bearing area 22 of the suspension pad 20. In this embodiment, the suspension pad 20 is a cylindrical sleeve machined from steel attached to the closing wall and one end of the cylindrical sleeve forms the bearing area.

[0090] The mounting ring 11 includes a flat interface area connected to the electric powertrain; the support area 22 is parallel to this flat interface area. The support area 22 is located on the free end 21 of the suspension mount furthest from the mounting ring 11.

[0091] The suspension pad includes a drilled and tapped hole 27 along a secondary axis X2 opening into the bearing area 22. A fixing screw 28 is inserted into a bore in the elastomer element 3 and screwed into a drilled and tapped hole 27 in 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 mount is a machined part attached to the inner face 16. The closing cover is made of two parts assembled by riveting. Alternatively, the two parts 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 stiffness of this stamped solution, the inner face of the stiffening stampings 24 serve as a centering surface for the suspension pad 20. A minimum of three stiffening stampings 24 will be made, distributed angularly around the secondary axis X2, to perform this centering function and to transfer 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 mount passes substantially through the center of gravity G of said closing hood. The secondary axis X2 is perpendicular to the machine axis X.

[0095] Figure 5 illustrates a fourth embodiment of the invention which differs from the third embodiment in that the closing hood 10 is obtained by casting so that the suspension block 20 is made of the same material as 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 cover 10 comprising a mounting rim 11, a closing wall 13, and a suspension mount 20 fused directly to the closing wall 13. The mounting rim 11 includes a flat interface area connected to the electric drive unit; the support area 22 is perpendicular to this flat interface area. The support area 22 is located on the free end 21 of the suspension mount furthest from the mounting rim 11. The cover 10 is fixed to the element of the electric drive unit comprising the cavity 5 by means of fixing screws 8. The cover 10 protects an electronic board 9 contained in the cavity 5 of the inverter 50.

[0097] The suspension pad 20 includes a drilled and tapped hole 27 along a secondary axis X2 opening into the bearing area 22. A fixing screw 28 is inserted into a bore in the elastomer element 3 and screwed into a drilled and tapped hole 27 in the suspension pad. A stiffening rib 25 connects the suspension pad 20 to the closing wall 13.

[0098] Other stiffening ribs 25 extend from the inner face 16 of the closing wall 13 towards the fixing perimeter 11. To improve the stiffening of the closing cover, the cavity 5 includes a support spacer 6 and one of the stiffening ribs 25 of the closing cover bears against said support spacer 6. A through hole is formed in the electronic board 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 clearly evident that it is by no means limited to them and that it includes all 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 claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. A 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 stud (20) connected to the closing wall (13), the suspension stud (20) comprising on one of its ends (21) a bearing area (22) arranged to receive an elastomer element, characterized in that the closing cover comprises at least one stiffening rib (25) connecting the suspension stud (20) to the closing wall (13) and in that the suspension stud (20) comprises a base (23) fused with the closing wall (13), the area of ​​the fusion surface of the base (23) is greater than one-eighth of the area of ​​the external face of the closing wall (13).

2. Closing cover (10) according to claim 1, in which the suspension block (20) includes a drilling-tapping along a secondary axis (X2) opening into the support area (22).

3. Closing cover (10) according to any one of the preceding claims, wherein the fixing perimeter (11) comprises a flat interface area (lia) with the electric powertrain, the support area (22) is parallel to the flat interface area (1la).

4. Closing cover (10) according to any one of claims 1 to 3, wherein the attachment perimeter (11) comprises a flat interface area (lia) with the electric powertrain, the support area (22) is perpendicular to the flat interface area (lia).

5. Closing cover (10) according to claim 1, in which stiffening ribs (25) extend from the melting surface of the base (23) towards the free end (21) of the suspension pad.

6. Closing cover (10) according to any one of the preceding claims, wherein stiffening ribs (25) extend from the inner face (16) of the closing wall (13) towards the fixing perimeter (11).

7. Closing cover (10) according to any one of claims 1 to 6, wherein the suspension lug (20) is made of material with the fixing perimeter (11) and the closing wall (13).

8. Closing cover (10) according to claim 1, wherein the bearing area (22) is cylindrical in shape along a secondary axis of revolution (X2) oriented perpendicularly to the closing wall (13).

9. Electric powertrain (1) for motor vehicle comprising: - a reversible electric machine (30) including a rotor (31) movable in rotation 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 housing (45) supporting at least partially the reversible electric machine and / or the inverter and / or the speed reducer; - a closing cover (10) according to any one of the preceding claims, attached to a cavity (5) formed on one of the elements of the electric powertrain selected from the reversible electric machine, the inverter, the speed reducer or the transmission housing.

10. Electric powertrain (1) according to the preceding claim, wherein the closing cover (10) supports an elastomer element (3) disposed on the bearing area (22) of the suspension stud (20).

11. Electric powertrain (1) according to claim 9 or 10, wherein the cavity (5) includes a support spacer (6), a stiffening rib (25) of the closing cover (10) bearing on said support spacer.

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