Powertrain noise reduction device

Abstract

The invention relates to a noise reduction device (7) for a powertrain equipped with a rotating electrical machine and an inverter, wherein the noise reduction device (7) comprises a network of grooves formed by a plurality of grooves (9) and made on a noise reduction surface (8) intended to be positioned opposite a component of the powertrain emitting sound vibrations, each groove having a plurality of ends (13) and defining one or more paths, each path being defined as a route between one end (13) of a groove and another end of said groove, each path having at least one change of direction (14). Figure for the abstract: 2

Description

Title of the invention: Noise reduction device for powertrain technical field

[0001] The invention relates to the field of powertrains for electric or hybrid vehicles and concerns in particular noise reduction devices for such powertrains. Technological background

[0002] In an internal combustion engine vehicle, the noise generated by the vehicle is primarily attributable to the internal combustion engine itself, and the sound vibrations of the other vehicle components are masked by the internal combustion engine. Therefore, in such a vehicle, it is not useful to attempt to reduce or filter the sound vibrations of vibrating elements that are masked by the internal combustion engine.

[0003] In an electric motor vehicle, the noise generated by vehicle components outside the powertrain does not mask the audible vibrations of the powertrain components. Therefore, a user can hear the noises emitted by these components, such as the gearbox, motor, and inverter, which can be particularly bothersome. Summary of the invention

[0004] One idea underlying the invention is to reduce the noise emitted by components of the electric powertrain in a vehicle.

[0005] According to one embodiment, the invention provides a noise reduction device for a powertrain equipped with a rotating electrical machine and an inverter, in which the noise reduction device comprises a network of grooves formed of a plurality of grooves and made on a noise reduction surface intended to be placed opposite an element of the powertrain emitting sound vibrations, each groove having a plurality of ends and defining one or more paths, each path being defined as a route between one end of a groove and another end of said groove, each path presenting at least one change of direction.

[0006] Thanks to these characteristics, the noise reduction device filters and dampens certain sound vibrations emitted by the powertrain component. Indeed, by positioning the noise reduction surface with the groove network opposite this component, the sound vibrations are directed to travel through this network. grooves and to dissipate in such a way as to reduce the noise emitted by this element.

[0007] According to embodiments, such a device may include one or more of the following characteristics.

[0008] According to one embodiment, each groove has two ends, three ends or more.

[0009] According to one embodiment, at least one change of direction is achieved using an angled portion, preferably an angled portion having an angle of angled between 45 and 180°, for example an angled portion having an angle of angled equal to 45°, 90°, 120°, or 180°.

[0010] According to one embodiment, at least one, several, or each path has several changes of direction.

[0011] According to one embodiment, at least one, several, or each path has one or more chicanes.

[0012] According to one embodiment, at least one, several or each groove of the groove network is covered with a layer of a viscoelastic material.

[0013] According to one embodiment, the viscoelastic material is chosen from a resin, a rubber, a polymer such as, for example, thermoplastic elastomers TPE.

[0014] According to one embodiment, the sound vibrations emitted by the powertrain are within a range of wavelengths and the groove network comprises a plurality of paths of different dimensions, the dimension of the paths being configured to attenuate the amplitude of the sound vibrations over at least a part of said wavelength range.

[0015] The dimension of each path is calculated by adding the lengths of the straight portions of the path from one end to the other end.

[0016] According to one embodiment, the noise reduction device has a general crown shape through which an orifice is passed and which is delimited by an inner circumference and an outer circumference, a shaft of the powertrain being intended to pass through the orifice of the noise reduction device, grooves of the groove network being oriented in a radial direction such that one end of said grooves is located near the inner circumference and the path of these grooves is configured to go from the inner circumference to the outer circumference.

[0017] According to one embodiment, each groove of the groove network is oriented in a radial direction such that one end of said grooves is located near the inner circumference and the path of these grooves is configured to go from the inner circumference to the outer circumference.

[0018] According to one embodiment, the noise reduction device is made of a material selected from aluminium, aluminium alloys, magnesium, the magnesium alloys, carbon, metamaterials and polymers.

[0019] According to one embodiment, the noise reduction device includes mounting holes configured to fix the noise reduction device to a powertrain component.

[0020] According to one embodiment, the invention also provides a powertrain for an electric vehicle comprising a noise reduction device as described above.

[0021] According to one embodiment, the powertrain comprises an axial flux rotating electric machine and a reducer, the axial flux rotating electric machine comprising a rotor, a stator arranged face to face with said rotor in an axial direction forming an air gap, and an enclosure in which the stator is placed, in which the noise reduction device is fixed to the enclosure of the axial flux rotating electric machine or is an integral part of the enclosure of the axial flux rotating electric machine and is located between the stator of the axial flux rotating electric machine and the reducer so that the noise reduction surface is facing the reducer.

[0022] According to one embodiment, the powertrain comprises a radial flux rotating electric machine and a reducer, the radial flux rotating electric machine comprising a rotor, a stator arranged around said rotor in a radial direction forming an air gap, and an enclosure in which the stator is placed, in which the noise reduction device is fixed to the enclosure or is an integral part of the enclosure so that the noise reduction surface is placed opposite the rotor.

[0023] According to one embodiment, the groove network is a first groove network, the noise reduction surface is a first noise reduction surface, and the noise reduction device comprises a second groove network formed of a plurality of grooves and made on a second noise reduction surface, the second noise reduction surface being located on the opposite side to the first noise reduction surface so as to be placed opposite the stator.

[0024] According to one embodiment, the powertrain comprises an inverter including a cover, the noise reduction device being attached to the cover of the inverter or forming an integral part of the cover of the inverter so that the noise reduction surface is oriented towards the inside of the inverter.

[0025] According to one embodiment, the powertrain comprises an ACDC converter or a DCDC converter including a cover, the noise reduction device being attached to the converter cover or forming an integral part of the converter cover.

[0026] According to one embodiment, the powertrain comprises a reduction gear including a housing, the noise reduction device being attached to the housing of the reducer or forming an integral part of the reducer housing.

[0027] According to one embodiment, the reducer comprises one or more reduction elements. In the case where the reducer comprises a plurality of reduction elements, the reducer constitutes a gearbox. Brief description of the figures

[0028] 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.

[0029] Fig. 1 represents a schematic cross-sectional view of an assembly comprising a rotating electrical machine with axial flux, equipped with a noise reduction device according to a first embodiment, and a reducer.

[0030] Fig. 2 represents a front view of a rotating electrical machine with axial flux directed towards the noise reduction device according to the first embodiment.

[0031] Figure 3 shows, in exploded view, a rotating electric machine with radial flux equipped with a noise reduction device according to a second embodiment.

[0032] Fig. 4 represents a front view of the noise reduction device according to the second embodiment.

[0033] Figure 5 shows a perspective view of a noise reduction device according to a third embodiment, intended to be fitted to a cover of an inverter. Description of embodiments

[0034] Figures 1 and 2 represent a rotating electrical machine with axial flux 1, of the permanent magnet type comprising two stators 2 and a rotor 3, the stators 2 being placed on either side of the rotor 3 and axially opposite the rotor 3, as can be seen in particular in [Fig. 1]. The rotor 3 is axially spaced from the two stators so as to form two air gaps.

[0035] In the example described, the axial flux electric machine 1 is configured to operate in motor mode and in generator mode. This is a permanent magnet synchronous motor for the propulsion of an electric vehicle.

[0036] The term "vehicle" means any vehicle capable of transporting goods or people, such as a car, truck, bicycle or drone.

[0037] The power of the electric machine may be between 4 kW and 80 kW. In the example considered, the electric machine advantageously has an operating voltage of less than 60 Volts, and preferably 48 Volts. Typically, the torque supplied by the electric machine is between 30 Nm and 2000 Nm. Alternatively, the electric machine may have an operating voltage of more than 60 V, or even more than 80 V or more than 100 V, in particular 300 V or Furthermore, in this case, the machine's power output can range from 60 kW to 300 kW.

[0038] The rotor 3 includes a plate carrying, on each of its surfaces arranged opposite one of the stators 3, a plurality of permanent magnets which have, for example, a disk sector shape.

[0039] The axial flux electric machine 1 includes a drive shaft 4 extending along an axis X, fixed to the rotor 3 and passing through the rotor 3 and the stators 2. The drive shaft 4 has an output pinion which meshes with a reducer 5.

[0040] The stators 2 each comprise a plurality of electrical windings and a plurality of teeth carrying the electrical windings. A housing is configured to carry the plurality of teeth.

[0041] The windings on the teeth together form a general stator winding, for example of the three-phase type. These windings are made by turns of electrical wire around each tooth.

[0042] The windings are configured to be electrically powered so as to generate a magnetic field capable of producing with the rotor 3 of the axial flux electric machine 1, an output torque.

[0043] In another embodiment not illustrated, the axial flux rotating electric machine 1 may also include a stator 2 and two rotors 3 placed on either side of the stator 2, facing axially with the stator 2.

[0044] The axial flux rotating electric machine 1 also includes an enclosure 6 in which the rotor 3 and the stators 2 are placed, as illustrated in [Fig.1].

[0045] The axial flux rotating electric machine 1 is equipped with a noise reduction device 7 which is fixed to the enclosure 6 so as to form a closed housing for the rotor 3 and the stators 2.

[0046] The noise reduction device 7 is thus placed between the axial flux rotating electrical machine 1 and the reducer 5, as shown in [Fig.1].

[0047] Fig. 2 represents more particularly the noise reduction device 7 according to a first embodiment which is fixed on the enclosure 6 of the axial flux rotating electrical machine 1.

[0048] In this embodiment, the noise reduction device 7 has a general ring shape through which an orifice 10 passes, the orifice 10 being traversed by the drive shaft. The noise reduction device 7 thus has an inner circumference delimiting the orifice 10 and an outer circumference on which lugs 11 are placed for attaching the noise reduction device 7 to the enclosure 6.

[0049] The noise reduction device 7 comprises a noise reduction surface 8 which is oriented towards the reducer 5. On this noise reduction surface 8, the device noise reduction 7 includes a network of grooves formed from a plurality of grooves 9 so as to present a maze shape.

[0050] In the example shown, the network of grooves forms a pattern 12 repeated by rotation around the X axis in the form of an angular section of a crown so that grooves 9 are present all around the drive shaft 4 on the noise reduction surface 8.

[0051] As shown in [Fig. 2], in this mode, a motif 12 has two grooves 9, each having two ends 13, one of which is located near the inner circumference. The grooves 9 are oriented radially such that their path runs from the inner circumference to the outer circumference. Thus, the second end 13 is radially distant from the first end 13.

[0052] The path of a groove 9 is defined as a path between one end of the groove 9 and another end of said groove 9. In the case, for example, of a groove 9 with two ends, as in the first embodiment, there is therefore only one possible path. In the case, for example, of a groove 9 with three ends, there are therefore three possible paths: from the first end to the second end, from the second end to the third end, and from the first end to the third end.

[0053] Furthermore, the path of each of the grooves 9 of the pattern 12 includes a multitude of changes of direction 14, here in the form of successive 180° bent sections that create a plurality of chicanes. This particular shape increases the path traveled by the sound source while exposing it to a multitude of pressure loss zones, in this case with the bent sections.

[0054] Fig. 3 represents a rotating radial flux electrical machine 20 which is equipped with a noise reduction device 7 according to a second embodiment.

[0055] In a manner known per se, the rotating radial flux electric machine 20 comprises a rotor 3 and a stator 2 situated around the rotor 3 in a radial direction.

[0056] The stator 2 and the rotor 3 are arranged inside an enclosure 6. In addition, the rotating electric machine with radial flux 20 includes a drive shaft (not shown in [Fig.3]) extending along an axis X, fixed to the rotor 3 and passing through the rotor 3 and the stator 2. The drive shaft has an output pinion which meshes with a reducer (not shown in [Fig.3]).

[0057] The rotating radial flux electric machine 20 is equipped with a noise reduction device 7 which is fixed to the enclosure 6 so as to form a cover for the enclosure 6.

[0058] The noise reduction device 7 is thus placed between the rotating radial flux electrical machine 20 and the reducer.

[0059] Fig. 4 represents more particularly the noise reduction device 7 according to a second embodiment which is fixed on the enclosure 6 of the rotating radial flux electrical machine 20.

[0060] In a manner analogous to the first embodiment, the noise reduction device 7 of the second embodiment has a general crown shape through which an orifice 10 passes, the orifice 10 being traversed by the drive shaft.

[0061] The noise reduction device 7 includes a noise reduction surface 8, visible in [Fig.4], which is turned towards the rotor 3 and the stator 2 of the rotating electrical machine 20. On this noise reduction surface 8, the noise reduction device 7 includes a network of grooves formed of a plurality of grooves 9 so as to present a maze shape.

[0062] Similar to the first embodiment, the groove network of the second embodiment forms a pattern 12 repeated by rotation around the X axis in the form of a crown section so that grooves 9 are present all around the drive shaft on the noise reduction surface 8.

[0063] The groove network paths of the second embodiment have fewer changes of direction 14, i.e., in the example of the 180° angled sections, namely four in number, compared to the first embodiment where more than ten changes of direction per path have been made. This variation in the number of changes of direction 14 and also in the path lengths makes it possible to adapt the noise reduction device 7 to the wavelength range of the sound vibrations whose amplitude it is necessary to reduce.

[0064] In another embodiment not shown, the noise reduction device 7 may advantageously have a second noise reduction surface opposite the first noise reduction surface 8 so that the second noise reduction surface is arranged opposite the rotor 3 and the stator 2 of the rotating electric machine with radial flux 20. In the example shown, the second noise reduction surface has a groove pattern identical to that of the first noise reduction surface 8. However, in other embodiments, the groove pattern of the second noise reduction surface is different from that of the groove pattern of the first noise reduction surface 8.

[0065] The noise reduction device 7 also advantageously comprises stiffeners 15 projecting from the first noise reduction surface 8 and / or the second noise reduction surface, made in the form of radially oriented strips and one or more concentric rings. The stiffeners 15 have a dimension in the axial direction that is smaller than the walls of the grooves 9.

[0066] The noise reduction device 7 has been described above in relation to two Specific embodiments in which it is used to reduce noise generated by the gearbox near a rotating electrical machine with radial flux 20 or a rotating electrical machine with axial flux 1. Other embodiments are also conceivable. Indeed, it is possible to equip any element of the powertrain emitting audible vibrations with a noise reduction device 7, such as, for example, the inverter, the ACDC converter, or the DCDC converter.

[0067] Fig. 5 represents a third embodiment of the noise reduction device 7 intended for an inverter of a powertrain.

[0068] In this embodiment, the noise reduction device 7 is implemented in the form of a plate having a generally polygonal shape. The noise reduction device 7 is an integral part of the inverter cover and comprises a noise reduction surface 8 intended to face the inverter elements that generate sound vibrations. On this noise reduction surface 8, the noise reduction device 7 includes a network of grooves formed by a plurality of grooves 9 so as to present a maze-like shape.

[0069] The pattern 12 of the grooves 19 is not repeated in this embodiment and has grooves 9 that interlock with each other so as to cover a large part of the noise reduction surface 8 of grooves 9.

[0070] The grooves 9, as shown in [Fig. 5], have more than two ends, such that each groove 9 has a plurality of paths. Each path has a plurality of changes of direction 14, which are formed here by 90° bent portions. Furthermore, the dimensions of the paths are configured to attenuate the amplitude of the sound vibrations over at least a portion of the wavelength range of the sound vibrations emitted by the inverter. It can be seen that, in this embodiment, the paths have different dimensions so as to attenuate the amplitude of the sound vibrations over several portions of said wavelength range.

[0071] 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.

[0072] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0073] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Claims

1. Noise reduction device (7) for a powertrain provided with a rotating electrical machine (1, 20) and an inverter, in which the noise reduction device (7) comprises a network of grooves formed of a plurality of grooves (9) and produced on a noise reduction surface (8) intended to be placed opposite an element of the powertrain emitting sound vibrations, each groove (9) having a plurality of ends (13) and defining one or more paths, each path being defined as a path between one of the ends (13) of a groove (9) and another end of said groove (9), each path having at least one change of direction (14).

2. A noise reduction device (7) according to claim 1, wherein at least one, several, or each path has several changes in direction (14).

3. A noise reduction device (7) according to claim 1 or claim 2, wherein at least one of the grooves (9) of the network of grooves is covered with a layer of a viscoelastic material.

4. A noise reduction device (7) according to one of claims 1 to 3, wherein the sound vibrations emitted by the powertrain are comprised in a wavelength range and wherein the network of grooves comprises a plurality of paths of different dimensions, the dimension of the paths being configured to attenuate the amplitude of the sound vibrations over at least a portion of said wavelength range.

5. Noise reduction device (7) according to one of claims 1 to 4, wherein the noise reduction device (7) has a general crown shape crossed by an orifice (10) and delimited by an internal circumference and an external circumference, a shaft (4) of the powertrain being intended to pass through the orifice (10) of the noise reduction device (7), grooves (9) of the network of grooves being oriented in a radial direction so that one end (13) of said grooves (9) is located near the internal circumference and the path of these grooves (9) is configured to go from the internal circumference to the external circumference.

6. Noise reduction device (7) according to one of claims 1 to 5, wherein the noise reduction device (7) is made in a material selected from aluminum, aluminum alloys, magnesium, magnesium alloys, carbon, metamaterials and polymers.

7. A noise reduction device (7) according to one of claims 1 to 6, wherein the noise reduction device (7) comprises fixing holes configured to fix the noise reduction device (7) to a component of the powertrain.

8. Powertrain for an electric vehicle comprising a noise reduction device (7) according to one of claims 1 to 7.

9. A powertrain according to claim 8 comprising an axial flux rotating electric machine (1) and a reduction gear (5), the axial flux rotating electric machine (1) comprising a rotor (3), a stator (2) arranged face to face with said rotor (3) in an axial direction forming an air gap, and an enclosure in which the stator (2) is placed, wherein the noise reduction device (7) is fixed to the enclosure of the axial flux rotating electric machine (1) or is an integral part of the enclosure of the axial flux rotating electric machine (1) and is located between the stator (2) of the axial flux rotating electric machine (1) and the reduction gear (5) so that the noise reduction surface (8) faces the reduction gear (5).

10. A powertrain according to claim 8 comprising a radial flux rotating electrical machine (20), the radial flux rotating electrical machine (20) comprising a rotor (3), a stator (2) arranged around said rotor (3) in a radial direction forming an air gap, and an enclosure in which the stator (2) is placed, wherein the noise reduction device (7) is fixed to the enclosure or is an integral part of the enclosure so that the noise reduction surface (8) faces the rotor (3).

11. A powertrain according to claim 8 comprising an inverter comprising a cover, the noise reduction device (7) being attached to the inverter cover or forming an integral part of the inverter cover such that the noise reduction surface (8) faces towards the inside of the inverter.

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