Motor vehicle powertrain provided with an electric traction machine protected against water

Abstract

One aspect of the invention relates to a motor vehicle powertrain (1) provided with an electric traction machine (4) secured to a rigid axle of a wheel train (2) of the powertrain (1), the powertrain (1) being characterized in that it comprises: a sealing cover (5) surrounding the electric traction machine (4), the sealing cover (5) comprising aeration means controllable between a closed position ensuring the sealing of the electric traction machine (4) and an open position allowing air outside the sealing cover (5) to come into contact with the electric traction machine (4); control means (7) arranged to control the aeration means between the closed position and the open position depending on a water level (8) on the ground (9) over which the powertrain (1) is traveling and / or depending on the presence of precipitation.

Description

DESCRIPTION TITLE: AUTOMOBILE POWERTRAIN EQUIPPED WITH A WATERPROOF ELECTRIC DRIVE MACHINE The present invention claims priority from French application No. FR2500627 filed on 22.01.2025, the content of which (text, drawings and claims) is incorporated herein by reference

[0001] The present invention relates to a motor vehicle powertrain equipped with an electric traction machine protected against water damage during fording or precipitation. The invention thus concerns the technical field of water protection for electric traction machines in vehicle powertrains. This aspect of the invention has interesting applications in the field of internal combustion and hybrid motor vehicles.

[0002] This is a known example of a three-wheeled electric vehicle powertrain with an electric traction motor positioned on a rigid axle of the rear wheel assembly. Positioning the electric traction motor on the rigid axle exposes it to water splashes and partial submersion when fording a stream.

[0003] This type of electric traction machine typically comprises, on the one hand, a mechanical compartment equipped with a rotor and stator, and on the other hand, an electronic compartment equipped with a converter. Water infiltration into this electronic compartment can cause short circuits, power losses, or even total failure of the electric traction machine.

[0004] In order to avoid recurring breakdowns, linked to water infiltration in the electric traction machine, impacting the reliability and image of the vehicle on the market, it is possible to equip these vehicles with an electric traction machine with a protection rating of type IP67 or IP69.

[0005] Specifically, the IP67 protection rating guarantees complete protection of the electric traction machine against dust and temporary immersion in water. As for the IP69 protection rating, it guarantees complete protection of the electric traction machine against powerful water jets.

[0006] Although these solutions offer high protection against the risk of water infiltration, they significantly increase the manufacturing costs of the vehicle and do not provide adequate ventilation for the electric traction machine, leading to risks of overheating.

[0007] A fan motor equipped with means of protection against water ingress into a motor ventilation opening is described in document EP-A2-1548286. While such a system ensures the cooling of the electric motor, it does not guarantee, in certain operating conditions, the complete absence of water ingress into the electric motor, particularly in the event of immersion.

[0008] The invention offers a solution to the problems mentioned above, by proposing an inexpensive motor vehicle powertrain equipped with a sealed electric traction machine that is adequately cooled.

[0009] In this context, the invention, in its broadest sense, relates to a motor vehicle powertrain equipped with an electric traction machine attached to a rigid axle of a wheel assembly of the powertrain, the powertrain being remarkable in that it comprises: A sealing cover surrounding the electric traction machine, said sealing cover having controllable ventilation means between a closed position ensuring the sealing of the electric traction machine and an open position allowing outside air to come into contact with said sealing cover; Control means arranged to control the ventilation means between the closed position and the open position according to a water level on the ground on which the powertrain travels and / or according to the presence of precipitation.

[0010] Thanks to the sealing hood equipped with controllable ventilation means between a closed position and an open position, the electric traction machine is inexpensive and is protected: When the ventilation means are in the closed position, against water infiltration during a ford crossing or heavy rain; When the ventilation means are in the open position, against overheating of the electric traction machine.

[0011] Because the electric traction machine is protected against water by the sealing cover, it is not necessary to use an electric traction machine with an IP67 or IP69 protection rating. This reduces the cost of the drive unit.

[0012] The controllable ventilation systems also allow the electric traction machine to be cooled efficiently.

[0013] Thus, the invention reconciles, at a lower cost, protection against water and optimal temperature management for the electric traction machine.

[0014] In addition to the characteristics mentioned in the preceding paragraph, the powertrain according to this aspect of the invention may have one or more additional characteristics from among the following, considered individually or according to all technically possible combinations.

[0015] According to a non-limiting aspect of the invention, the control means are also arranged to control the ventilation means between the closed position and the open position as a function of a temperature of the electric traction machine.

[0016] According to a non-limiting aspect of the invention, the ventilation means are formed by at least one flap pivotable around an axis of rotation.

[0017] According to a non-limiting aspect of the invention, the ventilation means are formed by two pivoting flaps, the two flaps being arranged opposite each other so as to create an air circulation corridor crossing the electric traction machine when the two flaps are in the open position.

[0018] According to a non-limiting aspect of the invention, the control means comprise: An electric motor mechanically coupled to the ventilation means, said electric motor being configured to move the ventilation means between the closed position and the open position; A water level sensor arranged to detect a water level on the ground on which the powertrain travels and / or a rain sensor arranged to detect the presence of precipitation; Control means arranged to control said electric motor according to a water level detected by said water level sensor and / or according to precipitation detected by said rain sensor.

[0019] According to a non-limiting aspect of the invention, the control means further comprise a temperature sensor arranged to detect the temperature of the electric traction machine, the control means further being arranged to control the electric motor as a function of a temperature of the electric traction machine detected by the temperature sensor.

[0020] According to a non-limiting aspect of the invention, the electric traction machine comprises an electronic compartment, the electronic compartment being covered with a water-repellent coating.

[0021] According to a non-limiting aspect of the invention, the electric traction machine has an IP24 protection rating.

[0022] According to a non-limiting aspect of the invention, the powertrain comprises three wheels.

[0023] According to a non-limiting aspect of the invention, the wheel assembly is a rear wheel assembly.

[0024] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0025] [Fig. 1] illustrates, schematically, a motor vehicle powertrain according to a non-limiting embodiment of the invention.

[0026] [Fig. 2] illustrates, schematically, a rear wheel assembly of a powertrain according to a non-limiting embodiment of the invention, said wheel assembly being equipped with an electric traction machine surrounded by a sealing hood.

[0027] [Fig. 3] illustrates, schematically, a sealing hood according to a non-limiting example of embodiment, said sealing hood having two ventilation flaps controlled in the closed position.

[0028] [Fig. 4] illustrates, schematically, the sealing hood shown in figure 3, with the two ventilation flaps being controlled in the open position.

[0029] The figures are presented for illustrative purposes only and are in no way limiting to the invention.

[0030] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0031] Figure 1 illustrates a powertrain 1 of an electric motor vehicle. The powertrain 1 is, according to this non-limiting embodiment, of the three-wheeled type.

[0032] The powertrain 1 includes a rear wheel assembly 2 conforming to that illustrated in Figure 2. The rear wheel assembly 2 is equipped with a rigid axle 3.

[0033] The powertrain 1 also includes an electric traction machine 4 attached to the rigid axle 3.

[0034] The electric traction machine 4 comprises, on the one hand, a mechanical compartment 4a equipped in particular with a rotor and a stator and, on the other hand, an electronic compartment 4b equipped in particular with a converter.

[0035] According to a non-limiting example of embodiment, the electric traction machine 4 has an IP24 protection rating.

[0036] The IP24 protection rating provides the electric traction machine 4 with limited protection against the intrusion of solid objects and exposure to water. Protecting only against low-intensity water spray, the IP24 rating is not optimal for humid environments or fording situations.

[0037] The use of an electric traction machine with an IP24 protection rating significantly reduces the cost of the drive unit 1. In order to protect the electronic compartment 4b from water ingress, the electronic compartment 4b is covered with a water-repellent coating.

[0038] The powertrain 1 further comprises a sealing cover 5 surrounding the electric traction machine 4. In Figure 2, only half of the sealing cover 5 is shown.

[0039] As illustrated in figures 3 and 4, the sealing hood 5 includes controllable ventilation means 6 between a closed position (see figure 3) ensuring the sealing of the electric traction machine 4 and an open position (see figure 4) allowing outside air to come into contact with the electric traction machine 4.

[0040] According to the non-limiting embodiment illustrated in figures 3 and 4, the ventilation means 6 are formed by two flaps pivotable around an axis of rotation (not shown), the two flaps being arranged opposite each other.

[0041] Thus, as illustrated in Figure 4, when the ventilation means 6 are in the open position, an airflow corridor 7 is created through the electric traction machine 4. The ventilation means 6 are positioned in the open position to cool the electric traction machine 4.

[0042] The drive unit 1 also includes control means 7 arranged to control the ventilation means 6 between the closed position and the open position according to a water level on the ground on which the drive unit 1 travels and according to the presence of precipitation.

[0043] According to the illustrated embodiment, the control means 7 include an electric motor 7a mechanically coupled to the ventilation means 6. This electric motor 7a is configured to move the ventilation means 6 between the closed position and the open position.

[0044] According to the illustrated, non-limiting example, the control means 7 also include: A water level sensor 7b arranged to detect a water level 8 on the ground 9 on which the drive unit 1 travels, this water level sensor 7b being able to be formed, for example, by a float level sensor; A rain sensor 7c arranged to detect the presence of precipitation, this rain sensor 7c being able to be formed, for example, by a radar type sensor; and a temperature sensor 7d arranged to detect the temperature of the electric traction machine 4, this temperature sensor 7d being able to be formed, for example, by a thermistor.

[0045] The control means 7 also include control means 7e arranged to control the electric motor 7a according to: From a water level detected by the water level sensor 7b; Precipitation detected by the 7c rain sensor; From a temperature of the electric traction machine 4 detected by the temperature sensor 7d.

[0046] Thus, when the water level 8 on the ground 9, over which the drive unit 1 travels, detected by the water level sensor 7b, is above a water level threshold, the control means 7e operate the electric motor 7a to position the ventilation flaps 6 in the closed position. In this position, the sealing cover 5 prevents any water infiltration into the mechanical compartment 4a and electrical compartment 4b of the electric traction machine 4. Then, when the water level 8 on the ground 9, over which the drive unit 1 travels, detected by the water level sensor 7b, falls below the water level threshold, the control means 7e operate the electric motor 7a to position the ventilation flaps 6 in the open position. In this position, an air circulation corridor 7 crossing the electric traction machine 4 is created and allows the electric traction machine 4 to be cooled.

[0047] Similarly, when the rainfall level detected by the rain sensor 7c exceeds a certain threshold, the control means 7e activate the electric motor 7a to position the ventilation flaps 6 in the closed position. In this position, the sealing cover 5 prevents any water infiltration into the mechanical compartment 4a and electrical compartment 4b of the electric traction machine 4. Then, when the rainfall level detected by the rain sensor 7c falls below the threshold, the control means 7e activate the electric motor 7a to position the ventilation flaps 6 in the open position.

[0048] Furthermore, when the temperature detected by the temperature sensor 7d is below a temperature threshold, the control means 7e actuates the electric motor 7a to position the ventilation flaps 6 in the closed position. In this position, the sealing cover 5 prevents the electric traction machine 4 from cooling when its temperature is too low. Then, when the temperature detected by the temperature sensor 7d rises above the temperature threshold, the control means 7e actuates the electric motor 7a to position the ventilation flaps 6 in the open position. In this position, an airflow channel 7 is created through the electric traction machine 4, allowing it to cool down.

[0049] The various aspects of the invention mentioned above offer numerous advantages. Among these are: Reduce the manufacturing costs of the powertrain 1; Protect the electric traction machine 4 against water infiltration during fording and / or precipitation; To allow optimal cooling of the electric traction machine 4 when its temperature is high by opening the ventilation means 6; Allowing the temperature of the electric traction machine 4 to increase when its temperature is low by closing the ventilation means 6.

Claims

DEMANDS

1. Powertrain (1) of a motor vehicle equipped with an electric traction machine (4) integral with a rigid axle (3) of a wheel assembly (2) of said powertrain (1), said powertrain (1) being characterized in that it comprises: - A sealing hood (5) surrounding said electric traction machine (4), said sealing hood (5) having ventilation means (6) controllable between a closed position ensuring the sealing of said electric traction machine (4) and an open position allowing outside air to come into contact with said electric traction machine (4); - Control means (7) arranged to control the ventilation means (6) between said closed position and said open position according to a water level (8) on the ground (9) on which the powertrain (1) travels and / or according to the presence of precipitation.

2. Powertrain (1) according to the preceding claim, characterized in that the control means (7) are also arranged to control the ventilation means (6) between the closed position and the open position as a function of a temperature of the electric traction machine (4). [Claims] Powertrain (1) according to any one of the preceding claims, characterized in that the ventilation means (6) are formed by at least one flap pivotable about an axis of rotation.

4. Powertrain (1) according to the preceding claim, characterized in that the ventilation means (6) are formed by two pivoting flaps, the two flaps being arranged opposite each other so as to create an air circulation corridor (7) crossing the electric traction machine (4) when the two flaps are in the open position. [Claims] Powertrain (1) according to any one of the preceding claims, characterized in that the control means (7) comprise: - An electric motor (7a) mechanically coupled to the ventilation means (6), said electric motor (7a) being configured to move the ventilation means (6) between the closed position and the open position; - A water level sensor (7b) arranged to detect a water level (8) on the ground (9) on which the powertrain (1) travels and / or a rain sensor (7c) arranged to detect the presence of precipitation; - Control means (7e) arranged to control said electric motor (7a) according to a water level (8) detected by said water level sensor (7b) and / or according to precipitation detected by said rain sensor (7c).

6. Powertrain (1) according to claims 2 and 5, characterized in that the control means (7) further comprise a temperature sensor (7d) arranged to detect the temperature of the electric traction machine (4), the control means (7e) further arranged to control the electric motor (7a) as a function of a temperature of the electric traction machine (4) detected by said temperature sensor (7d).

7. Powertrain (1) according to any one of the preceding claims, characterized in that the electric traction machine (4) comprises an electronic compartment (4b), said electronic compartment (4b) being covered with a water-repellent coating. [Claims] Powertrain (1) according to any one of the preceding claims, characterized in that the electric traction machine (4) has an IP24 protection rating. [Claims] Powertrain (1) according to any one of the preceding claims, characterized in that the powertrain (1) comprises three wheels.

10. Powertrain (1) according to any one of the preceding claims, characterized in that the wheel assembly (2) is a rear wheel assembly.

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