MOTOR VEHICLE AXLE WITH ELECTRIC MOTORIZATION AND HIGH GROUND CLEARANCE

Abstract

The invention relates to a motor vehicle axle (1) equipped with at least one electric propulsion module (2) comprising an electric machine (20) and a transmission system (22) for transmitting the torque generated by the electric machine, said electric machine (20) comprising a rotation shaft (200) coupled to an axis of rotation (10) of a wheel (11, 12) of the axle by the transmission system (22). The electric propulsion module (2) is positioned above the axis of rotation (10) in a position of use of the axle. The rotation shaft (200) of the electric machine (20) is perpendicular to the axis of rotation (10) of the axle, the transmission system (22) comprising an angle transmission for coupling the rotation shaft (200) of the electric machine to the axis of rotation (10) of the axle. This arrangement makes it possible to produce an axle with high ground clearance. Abstract Figure: Figure 1

Description

Title of the invention: MOTOR VEHICLE AXLE WITH ELECTRIC MOTORIZATION AND HIGH GROUND CLEARANCE

[0001] The invention relates to an axle for a motor vehicle with electric motorization and high ground clearance.

[0002] Electric or hybrid vehicles are equipped with one or more electrical machines to ensure the vehicle's drive.

[0003] In general, an electric machine is associated with a torque reducer positioned on the axle, the machine being arranged so that its drive shaft is coaxial or parallel to the axis of rotation of the axle, typically mounted in front or behind the axis of rotation of the axle in a horizontal plane. These configurations, however, reduce the ground clearance of the vehicle, which is not desired, particularly for four-wheel drive vehicles.

[0004] The invention aims to remedy all or part of the aforementioned drawbacks by proposing an axle equipped with an electric propulsion module whose ground clearance is not impacted by the presence of this propulsion module.

[0005] To this end, the invention proposes a motor vehicle axle equipped with at least one electric propulsion module comprising an electric machine and a system for transmitting the torque generated by the electric machine, said electric machine comprising a rotation shaft coupled to an axis of rotation of a wheel of the axle by the transmission system, characterized in that: - the electric propulsion module is positioned above the axis of rotation in an axle usage position, - the rotation shaft of the electric machine is perpendicular to the rotation axis of the axle, - the transmission system includes an angle transmission for coupling the rotation shaft of the electric machine to the rotation axis of the axle.

[0006] This arrangement makes it possible to equip the axle with an electric propulsion module without reducing the ground clearance of the vehicle, the module being located above the axle axis.

[0007] The electrical machine may be an asynchronous machine, a synchronous machine with permanent magnets or with wound excitation (with wound rotor) or a variable reluctance machine, preferably a synchronous machine with permanent magnets or with wound excitation. The electrical machine may be an axial, radial or transverse flux machine, comprising at least one rotor and at least one stator.

[0008] Advantageously, the electric machine may be a flux electric machine axial. This type of machine, which typically comprises at least one stator and at least one rotor which are disc-shaped, has a reduced axial size facilitating its positioning above the axle, even when the size is reduced vertically.

[0009] Alternatively, the electric machine may be a radial flux electric machine, advantageously with small axial size. In particular, radial flux machines with permanent magnets may be used to reduce the radial size.

[0010] Advantageously, the transmission system may comprise a torque reducer coupled on the one hand to the rotation shaft of the electric machine and on the other hand to the rotation axis of the axle with angle transmission. It is advantageously located between the electric machine and the rotation axis of the axle.

[0011] A reducer typically comprises a motor shaft which can either be made in one piece with the rotation shaft of the electric machine, thus forming with the latter a geared motor, or be coupled to the rotation shaft of the electric machine coaxially, parallel or perpendicularly. The torque reducer can be of the epicyclic or pinion type.

[0012] In one embodiment, the transmission system may further comprise a differential mounted on the axis of rotation of the axle. The torque reducer is then coupled with angle transmission to the axis of rotation of the axle via the differential. This embodiment is more particularly suitable for axles in which the wheels are driven in rotation by a single axis of rotation.

[0013] Advantageously, the electric propulsion module may comprise a voltage converter supplying the electric machine, and optionally at least one other element chosen from a control system of the electric propulsion module and a device for charging a battery of the vehicle. This may facilitate assembly and optimize the use of the space occupied by the propulsion module.

[0014] Advantageously, the electric propulsion module may comprise a module housing receiving the electric machine. The torque reducer is then located under the electric machine inside said module housing or inside a reducer housing fixed under the module housing. A compact and simple to assemble structure is thus achieved.

[0015] At least one element selected from the voltage converter, the control system and the charging device can then be mounted inside the module housing, inside the reducer housing, on a lower face of the module housing next to the torque reducer or on an upper face of the module housing, or inside a housing fixed to a lower face of the module housing next to the torque reducer. These different arrangements also have the advantage of being compact. When a single module housing is used, the electric drive module can be produced and mounted particularly simply and with reduced weight compared to a solution using two or more housings. This is also the case, although to a lesser extent, when the gearbox housing houses elements other than the torque reducer. In particular, a gearbox housing can be produced with the same dimensions as the module housing in a plane perpendicular to the rotating shaft and with the same height as the torque reducer.

[0016] The axle of the present invention can be used as a front axle, the electric machine being used for example as a main electric machine for moving the vehicle, or as a rear axle, the electric machine being used for example as a backup electric machine for acceleration or four-wheel drive vehicles.

[0017] Advantageously, the axle according to the invention can be provided with a single electric propulsion module. In one embodiment, the axle according to the invention can be provided with a single electric propulsion module whose transmission system comprises a differential mounted on the axis of rotation of the wheels.

[0018] The invention thus also relates to a motor vehicle comprising at least one axle according to the invention. This vehicle may in particular comprise an axle according to the invention as a front axle, a rear axle or both.

[0019] Advantageously, the electric propulsion module can be positioned under the floor of the vehicle, optionally under a floor housing intended to receive a spare wheel. In particular, the electric propulsion module can then be housed at least partly inside this housing, for example under the spare wheel, or in place of the latter, which makes it possible to reduce the space required for the propulsion module without having to modify the floor of the vehicle.

[0020] Other features and advantages of the invention will emerge from reading the description given below of several particular embodiments of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0021] [Fig-1] [Fig.l] is a front view of an axle according to an embodiment of the invention.

[0022] [Fig.2] [Fig.2] is an enlarged view of a portion of [Fig.l].

[0023] [Fig.3] [Fig.3] partially represents from the front an axle according to another mode of realization of the invention.

[0024] [Fig.4] [Fig.4] is a bottom view of the axle shown in [Fig.3].

[0025] In the present description, the terms upper, lower, above, below are defined with respect to the vertical direction when the axle is in the use position, mounted on the vehicle resting on horizontal ground. The axes X, Y, Z, correspond respectively to the longitudinal (front to back), transverse and vertical axis of the vehicle. The vertical direction thus corresponds to the direction of gravity.

[0026] [Fig.l] represents an axle 1 of a motor vehicle equipped with at least one electric propulsion module 2, here only one.

[0027] The axle 1 typically comprises a rotation axis 10 for driving the wheels 11, 12. In this example, the rotation axis 10 drives the two wheels 11, 12 of the axle in rotation. The invention is however not limited to this embodiment, and it would be possible to provide an axle 1 comprising one rotation axis per wheel, the axle being equipped with one or two electric propulsion modules.

[0028] The electric propulsion module 2 comprises an electric machine 20 and a system 22 for transmitting to the axle 1 the torque generated by the electric machine.

[0029] The electric machine 20 typically comprises a rotation shaft 200 (represented symbolically in the figures) coupled to the rotation axis 10 of the axle by the transmission system 22.

[0030] According to the invention, in a position of use of the axle 1, the electric propulsion module 2 is positioned above the axis of rotation 10 of the axle, in particular between the latter and the floor 3 of the vehicle symbolically represented by a dotted line in [Fig.l]. In addition, the rotation shaft 200 of the electric machine is perpendicular to the axis of rotation 10 of the axle, it therefore extends in the direction Z in the position of use of the axle. In order to couple the rotation shaft 200 of the electric machine 20 to the axis of rotation 10 of the axle, the transmission system 22 comprises an angle transmission. It is thus understood that the ground clearance of the axle is not, or only slightly, impacted by the electric propulsion module 2.It will be noted that the electric propulsion module 2 can be positioned under the floor 3 of the vehicle, in particular under a housing 4 of the floor intended to receive a spare wheel and shown schematically [Fig.l].

[0031] The electrical machine 20 may be an asynchronous machine, a synchronous machine with permanent magnets or wound excitation (with wound rotor) or a variable reluctance machine. It may be an axial, radial or transverse flux machine, comprising at least one rotor and at least one stator.

[0032] The use of an axial flux electric machine 20 makes it possible to reduce the size of the electric propulsion module in the direction of the rotation shaft 200 of the electric machine and to facilitate the installation of the module above the rotation axis 10 of the axle.

[0033] Depending on the space available above the axis of rotation 10 of the axle, it is also possible to use other types of electrical machine, and in particular an electrical machine 20 with radial flux, permanent magnets or wound excitation, or other.

[0034] Generally, it will be possible to use an electric machine 20 whose dimensions along its rotation shaft 200 are 10 to 20 cm.

[0035] The electric propulsion module 2 generally comprises a module housing 23 receiving the electric machine. This module housing 23 can house only the electric machine 2 or other elements as described below.

[0036] The transmission system 22 typically comprises a torque reducer 220 which can define one or more distinct ratios. This torque reducer 220 is coupled on the one hand to the rotation shaft 200 of the electric machine and on the other hand to the rotation axis 10 of the axle with angle transmission.

[0037] The torque reducer 220 is typically located below the electric machine 20 and above the axis of rotation 10 of the axle, in other words between the electric machine 20 and the axis of rotation 10 of the axle vertically in the position of use of the axle.

[0038] Any type of torque reducer can be used.

[0039] The torque reducer 220 can thus be a reducer with several pinions, for example example with two or more pinions, or perhaps an epicyclic gear reducer.

[0040] The torque reducer 220 may comprise a rotation shaft which is coupled to the rotation shaft 200 of the electric machine coaxially, parallel or perpendicularly.

[0041] It may be a reducer integrated into the electric machine 20 and forming with it a geared motor. The torque reducer 220 then comprises a rotation shaft which is made in one piece with the rotation shaft 200 of the electric machine. In this case, the electric propulsion module 2 comprises a module housing 23 receiving the electric machine 20 and the torque reducer 220 (not shown).

[0042] Alternatively, the rotation shaft of the reducer can be coupled to the rotation shaft 200 of the electric machine. The torque reducer 220 is then housed in a reducer housing 24 of the propulsion module, as shown in Figures 1 to 4. In Figures 1 and 2, the reducer housing 24 is shaped to house only the torque reducer 220. In Figures 3 and 4, the reducer housing 24 is shaped to house other elements of the electric propulsion module, as described below.

[0043] The transmission system 22 also most often comprises a differential 224, allowing the wheels to be rotated by the electric propulsion module at different speeds when passing through a curve. The differential 224 is typically mounted on the axis of rotation 10 of the axle, in a coaxial manner, as shown in the figures. It is then the only element of the axle which is likely to impact the ground clearance thereof. The torque reducer 220 is then coupled with angle transmission to the axis of rotation 10 of the axle via the differential 224.

[0044] When each wheel is rotated by an electric propulsion module, the differential 224 can be omitted. The torque reducer 220 is then directly coupled to the rotation axis 10 of the axle with angle transmission.

[0045] The electric propulsion module 2 typically comprises other elements, in particular a voltage converter 25 supplying the electric machine. The voltage converter may be an inverter / rectifier, for example implementing field effect transistors, such as MOSFET transistors, or IGBTs.

[0046] The electric propulsion module 2 may also comprise a control system 26 of the electric propulsion module, typically configured to automatically activate the electric propulsion module so that it provides engine torque to the axle. The control system 26 may comprise a digital processing unit, implementing one or more microcontrollers. Where appropriate, the control system 26 may communicate directly or indirectly with a remote data server via a telephone communication network.

[0047] The control system 26 of the electric propulsion module may be external to the propulsion module. The control system is then, for example, integrated into a vehicle control device, also called a “vehicle control unit” (VCU) in English.

[0048] The control system 26 may be housed inside the module housing 23 (not shown), or fixed thereto, in particular to a lower face thereof, next to the torque reducer as shown [Fig. 2], or else housed inside the reducer housing, as shown in Figures 3-4, or else fixed to an upper face of the module housing 23 (not shown).

[0049] The electric propulsion module 2 may also comprise a device 27 for charging a battery of the vehicle. This charging device 27 may be configured to recover braking energy, to receive a current from a charging terminal or even to charge the battery from the electric machine operating as an alternator.

[0050] The charging device 27 may be housed inside the module housing 23 (not shown), or fixed to it, in particular to an upper face thereof as shown [Fig.2], or even to a lower face of the module housing 23, for example next to the torque reducer (not shown), or even housed inside the reducer housing 24, as shown in Figures 3-4.

[0051] Alternatively, a housing separate from the reducer 24 and module 23 housings could be provided and located between the module housing 23 and the rotation axis 10 of the axle. This additional housing, for example fixed to a lower face of the module housing 23, next to the torque reducer 220, could receive the converter 25 and / or the control system 26 and / or the charging device 27.

[0052] These different configurations make it possible to use the free space left between the electric machine and the axis of rotation of the axle to house one or more elements and thus optimize the occupation of space. They also make it easier to mount the different parts of the axle, and to reduce the number of parts, in particular when a single housing is used.

Claims

Claims

1. Axle (1) of a motor vehicle equipped with at least one electric propulsion module (2) comprising an electric machine (20) and a transmission system (22) for the torque generated by the electric machine, said electric machine (20) comprising a rotation shaft (200) coupled to an axis of rotation (10) of a wheel (11, 12) of the axle by the transmission system (22), and in which: - the electric propulsion module (2) is positioned above the axis of rotation (10) in a position of use of the axle, - the rotation shaft (200) of the electric machine (20) is perpendicular to the axis of rotation (10) of the axle,- the transmission system (22) comprises an angle transmission for coupling the rotation shaft (200) of the electric machine to the rotation axis (10) of the axle and a torque reducer (220) coupled on the one hand to the rotation shaft (200) of the electric machine and on the other hand to the rotation axis (10) of the axle with angle transmission, the electric propulsion module (2) comprising a module housing (23) receiving the electric machine (20), the torque reducer (220) being located under the electric machine inside said module housing (23) or inside a reducer housing (24) fixed under the module housing (23), characterized in that the electric propulsion module (2) comprises a voltage converter (25) supplying the electric machine (20), and optionally at least one other element chosen from a control system (26) of the electric propulsion module and a charging device (27) of a vehicle battery,and in that at least one element selected from the voltage converter (25), the control system (26) and the charging device (27), is mounted inside the reducer housing (24), at a lower face of the module housing (23) next to the torque reducer, or inside a housing fixed to a lower face of the module housing (23) next to the torque reducer.,

2. Axle (1) according to claim 1, characterized in that the electric machine (20) is an axial flux electric machine.

3. Axle (1) according to claim 1, characterized in that the electric machine (20) is a radial flux electric machine.

4. Axle (1) according to any one of claims 1 to 3, characterized in that the transmission system (22) further comprises a differential (224) mounted on the axis of rotation (10) of the axle, and in that the torque reducer (220) is coupled with angle transmission to the axis of rotation (10) of the axle via the differential (224).

5. Motor vehicle characterized in that it comprises at least one axle (1) according to any one of claims 1 to 4.

6. Motor vehicle according to claim 5, characterized in that the electric propulsion module (2) is positioned under the floor of the vehicle, optionally under a floor housing intended to receive a spare wheel.

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