Layout for electric or hybrid motor vehicles and electric motor for such a layout

Abstract

Title: Layout for an electric or hybrid motor vehicle and electric motor for such a layout. Layout (2) for a motor vehicle (1) comprising a gearbox housing (30), an electric motor (4) having a rotor shaft (41) (42) and including a bore (45) opening at a first end (41a) of the shaft (41), the electric motor (4) including a sealing device (5) comprising a hollow nozzle (50) disposed on the first end (41a) of the shaft (41) and configured to extend partially into the opening (31), the nozzle (50) including a plurality of grooves (54). Abstract figure: Figure 2

Description

Title of the invention: Arrangement for a motor vehicle with electric or hybrid motor and electric motor for such an arrangement

[0001] The invention relates to an arrangement for a motor vehicle, particularly for a vehicle with an electric or hybrid motor. The invention also relates to an electric motor for such an arrangement. The invention finally relates to a vehicle with an electric or hybrid motor equipped with the arrangement and / or the electric motor.

[0002] Vehicles with electric or hybrid motors conventionally comprise at least one electric traction and / or propulsion motor for moving the vehicle. The electric motor comprises, in a known manner, a rotor mounted on a shaft and rotating near a stator. Since the rotor moves at a high rotational speed, for example of the order of 16,000 revolutions per minute, the electric motor tends to heat up during its operation.

[0003] Similarly, heating can be observed within a vehicle gearbox making it possible to regulate the rotation speed of an element in contact with the ground, such as a wheel, relative to the rotation speed coming out of the electric motor.

[0004] In order to limit such heating and to preserve the integrity of the electric motor, the gearbox and their operation, it is known to integrate one or more heat treatment systems, in particular cooling systems, into the vehicle. An example of known architecture, for example implemented when the motor is partly integrated into a gearbox of the vehicle, consists of providing a cooling system allowing the heat treatment of the gearbox on the one hand and the electric motor on the other hand. The shaft of the electric motor is then partly hollow so as to allow the fluid connection between a first cooling fluid circuit, in particular oil, present in at least a part of the gearbox, and at least a second circuit included in the electric motor.In order to ensure sealing at the interface between the rotor shaft and the gearbox, it is known to integrate a sealing device such as a seal, particularly a high-speed rotary seal. Such a sealing device nevertheless has the disadvantages of being bulky, expensive, complicating the installation of the electric motor, particularly in the gearbox, and presenting friction losses which are detrimental to overall efficiency.

[0005] The invention falls within this context and aims to propose an alternative to known electric motors making it possible to ensure suitable sealing in a less bulky and less expensive manner. Other objectives of the invention are to limit the friction losses and simplify the installation of such an electric motor in the vehicle.

[0006] The invention relates to an arrangement for a motor vehicle comprising a gearbox casing configured to allow the circulation of a cooling fluid at a first circuit and comprising an opening, delimited by at least one edge of the casing, in fluid connection with said circuit. The arrangement also comprises an electric motor comprising a rotor shaft extending along a first direction and comprising a bore opening at a first end of the shaft so as to allow a fluid connection between the first circuit and at least a portion of the electric motor.In particular, the electric motor comprises a sealing device comprising a hollow cannula disposed on the first end of the shaft and configured to extend partly into the opening to allow a fluid connection between the first circuit and the shaft, an outer surface of the cannula comprising a plurality of grooves extending at least partly transversely to the first direction and arranged opposite the at least one edge of the opening. In particular, the sealing device, in particular the cannula, is configured to allow a fluid connection between the first circuit and the bore of the shaft.

[0007] In particular, the cannula of the sealing device is attached and mounted on the shaft.

[0008] For example, the cannula of the sealing device is made of a metallic material, such as steel or aluminum.

[0009] In particular, the plurality of grooves comprises: - at least two grooves parallel, or substantially parallel, to each other; and / or - at least one helical groove relative to the first direction.

[0010] According to an exemplary embodiment, all or part of the plurality of grooves has a depth, relative to the outer surface of the shaft, greater than or equal to 0.10 mm.

[0011] Optionally, a free end of the cannula of the sealing device comprises at least one chamfer.

[0012] Optionally, the cannula comprises a shoulder configured to be arranged in abutment against the rotor shaft along the first direction and / or configured to extend into a recess of the casing comprising the opening.

[0013] For example, the shaft bore is defined by a first dimension along a direction orthogonal to the first direction and: - the cannula of the sealing device is at least partly inserted into the bore; and / or - the hollow cannula of the sealing device is defined by a second dimension, defined at an inner surface of the cannula, opposite the outer surface, strictly less than the first dimension of the tree.

[0014] The invention also relates to an electric motor for an arrangement according to the invention, comprising: - a shaft extending along a first direction and comprising a bore opening at a first end configured to allow a fluid connection with a cooling fluid circuit of a gearbox; and - a sealing device comprising an at least partly cylindrical hollow cannula disposed on the first end of the shaft and configured to extend partly into an opening of the gearbox in order to allow a fluid connection between the circuit and the shaft, an outer surface of the cannula comprising a plurality of grooves extending at least partly along a direction transverse to the first direction.

[0015] The invention finally relates to a vehicle with an electric or hybrid motor comprising an arrangement and / or an electric motor according to the invention.

[0016] Other details, characteristics and advantages will emerge more clearly on reading the detailed description given below, for informational and non-limiting purposes, in relation to the various exemplary embodiments illustrated in the following figures:

[0017] [Fig.l] is a schematic representation of an embodiment of a vehicle equipped with an arrangement according to the invention, a gearbox and an electric motor.

[0018] [Fig.2] is a schematic representation of the arrangement according to the invention.

[0019] [Fig. 3] is a schematic representation of an engine sealing device electric according to a first example of realization.

[0020] [Fig.4] is a schematic representation of the sealing device of the electric motor according to a second exemplary embodiment.

[0021] [Fig.5] is a schematic representation of the sealing device of the electric motor according to a third exemplary embodiment.

[0022] [Fig. 1] schematically illustrates an exemplary embodiment of a motor vehicle 1 according to the invention. The vehicle 1 is a motor vehicle with an electric or hybrid engine. Also, the vehicle 1 can be of any type, for example, a private vehicle, a utility vehicle, a truck or a bus. In particular, the vehicle 1 in question can be a connected and / or autonomous vehicle.

[0023] The motor vehicle 1 is equipped with an arrangement 2 according to the invention. Generally, the arrangement 2 comprises at least one gearbox casing 30 and an electric motor 4, the latter being equipped with a sealing device 5. The vehicle 1 thus comprises a gearbox 30 and the electric motor 4. For example, the electric motor 4 is a traction and / or propulsion of the vehicle 1. Particularly, advantageously, the electric motor 4 is at least partially arranged within the gearbox 30. It is understood that the characteristics relating to the electric motor 4 set out below in the context of the arrangement 2 extend to an electric motor 4 according to the invention intended for the arrangement 2.

[0024] The gearbox 30 comprises at least one casing 3. The term "casing" means an envelope, in particular a metal one. According to an exemplary embodiment, the gearbox 30 may comprise a plurality of assembled casings 3. The at least one casing 3 of the gearbox 30 is advantageously configured to allow the circulation of a cooling fluid FR at the level of at least one part of a first circuit CL. For example, the cooling fluid FR is an oil, in particular lubricating and / or cooling oil intended for the heat treatment of at least one part of the gearbox 30. For example, the first circuit Cl of cooling fluid FR is intended for the heat treatment of at least one pinion of the gearbox 30.

[0025] The at least one casing 3 comprises an opening 31 arranged in fluid connection with the first circuit CL. The opening 31 is delimited by one or more edges 32. It allows a fluid connection to the first circuit CL. In particular, the opening 31 allows the implementation of a fluid connection between the first circuit Cl and a second circuit C2, included in the electric motor 4, so that the same cooling fluid FR supplies these two circuits, as further explained below. Optionally, the arrangement 2 and / or the vehicle 1 comprises a pump, not shown, capable of circulating the cooling fluid FR in the first circuit Cl and / or the second circuit C2.

[0026] As illustrated in Figures 2 to 5, the electric motor 4 comprises a shaft 41, a rotor 42 and a stator 43. Optionally, the electric motor 4 comprises a housing 44 delimiting an internal volume 400 in which the rotor 42, the stator 43 and at least part of the shaft 4L are arranged. Also, the second circuit C2 is at least partly arranged in the internal volume 400 of the electric motor 4.

[0027] The shaft 41 extends along a first direction 100 and is in particular centered on an axis of rotation 450 parallel to, or coincident with, the first direction 100. The shaft 41 is configured to be moved in rotation about the axis of rotation 450 and is the shaft 41 of the rotor 42. The rotor 42 is thus fixed to the shaft 41 so that the shaft 41 and the rotor 42 are able to rotate concomitantly about the axis of rotation 450, or substantially about the axis of rotation 450. Preferably, the rotor 42 is arranged so as to pivot relative to the stator 43 and opposite it.

[0028] The shaft 41 comprises a bore 45 opening at a first end 41a of the shaft 4L. By “opening” is meant that the bore 45 is open towards the environment outside the shaft 41. The first end 41a of the shaft 41 is arranged at the edges 32 of the opening 31 of the casing 3. The shaft 41 is thus able to implement the fluid connection between the first circuit C1 and at least a part of the electric motor 4, in particular the second circuit C2. The bore 45 extends over a part of a length of the shaft 41, measured along the first direction 100 between the first end 41a and a second end 41b of the shaft 41, opposite the first end 41a and being the most distant from the opening 31 of the casing 3.

[0029] Optionally, the shaft 41 comprises at least one channel 46 connected to the bore 45 and opening into an outer face 410a of the shaft 4L. In other words, the at least one channel 46 is arranged so as to extend from the bore 45 to the outer face 410a of the shaft 4L. For example, the at least one channel 46 extends transversely, or even orthogonally, to the axis of rotation 450 and / or to the first direction 100. For example, as illustrated, the shaft 41 comprises a plurality of channels 46. The channels 46 are configured to allow the fluid connection between the first volume and the bore 45, and, consequently, between the second circuit C2 and the first circuit CL. An example of circulation of the cooling fluid FR in the shaft 41 is illustrated by arrows in Figures 3 to 5.

[0030] The sealing device 5 comprises a cannula 50 arranged on the shaft 4L. The cannula 50 is a hollow part that is at least partly cylindrical. It comprises an inner surface 51a, delimiting a through passage 52 capable of allowing the circulation of the cooling fluid FR. By "through passage", it is meant that the passage 52 extends from one side to the other within the cannula 50, in particular along the first direction 100. According to a non-limiting exemplary embodiment, the cannula 50 comprises at least one cylindrical portion with a circular or substantially circular base.

[0031] The cannula 50 is arranged on the first end 41a of the shaft 41 of the rotor 42 and is configured to extend partly into the opening 31 of the casing 3 of the gearbox 30, that is to say opposite the edges 32 of the casing 3. Thus, when the arrangement 2 is provided within the vehicle 1, the cannula 50 extends between the shaft 41 and the opening 31 in order to allow the fluid connection between the first circuit C1 and the bore 45 of the shaft 4L. In other words, the cannula 50 is interposed between at least a portion of the shaft 41 and the opening 31 of the casing 3 along the first direction 100. The cannula 50 thus further allows the fluid connection between the first circuit C1 and the second circuit C2.

[0032] In particular, the cannula 50 comprises a first extreme portion 53a, corresponding to a portion of the cannula 50 furthest from the shaft 41, and a second extreme portion 53b, opposite the first extreme portion 53a, i.e. proximal relative to the shaft 4L. When the arrangement 2 according to the invention is assembled, the first end portion extends at the opening 31 and / or in the opening 31 while the second end portion is connected to the first end 41a of the shaft 41. Also, the first end portion 53a is at least partly complementary in shape to the opening 31 while the second end portion 53b is at least partly complementary in shape to the shaft 41. For example, the first end portion 53a and / or the second end portion 53b is cylindrical.

[0033] The passage 52 formed by the cannula 50 extends in the continuity of the bore 45. According to a particular, optional exemplary embodiment, the passage 52 of the cannula 50 and the bore 45 are centered on the axis of rotation 450 and / or the first direction 100.

[0034] Optionally but preferably, the cannula 50 of the sealing device 5 is attached and mounted on the first end 41a of the shaft 41. For example, the cannula 50 is mounted on the shaft 41 by shrink fitting.

[0035] Optionally but preferably, the cannula 50 of the sealing device 5 is made of a metallic material, such as steel or aluminum. In particular, the cannula 50 is made of a material capable of withstanding temperatures less than or equal to 150°C.

[0036] According to a preferred embodiment, the cannula 50 is sized and arranged so as to be at least partially inserted into the bore 45. In other words, an external dimension of the cannula 50, measured along a direction orthogonal to the first direction 100, is less than or equal to a dimension of the bore 45 measured along this same direction. The dimension considered may be a diameter or a diagonal for example.

[0037] Furthermore, optionally, the passage 52 of the cannula 50 is defined by a second dimension, measured at the level of the internal surface 51a of the cannula 50, strictly less than the first dimension of the bore 45 of the shaft 41 of the rotor 42. A part of the cannula 50 extending into the bore 45, the space available for the circulation of the cooling fluid FR through the cannula 50 is thus smaller than the space available at the level of the rest of the shaft 4L. Such a principle advantageously makes it possible to limit the reflux of the cooling fluid FR from the bore 45 of the shaft 41 towards the passage 52 of the cannula 50.

[0038] The cannula 50 comprises a plurality of grooves 54, arranged at an outer surface 51b of the cannula 50, opposite the inner surface 51a and configured to be turned towards the edges 32 of the opening 31. Said grooves 54 extend over all or part of an outer periphery of the cannula 50. Preferably, each groove 54 extends over the entire periphery of the outer surface 51b of the cannula 50. Said grooves 54 form depressions relative to the outer surface 51b. The grooves 54 extend at least in part along a transverse direction, or even orthogonal to the first direction 100. The grooves 54 are arranged in the cannula 50 so as to extend at the level of the opening 31, opposite edges 32 of the casing 3 delimiting the latter. In this case, the grooves 54 are arranged in the first extreme portion 53a of the cannula 50.

[0039] The grooves 54 generate a pressure drop between the outer surface 51b of the cannula 50 and the edges 32 of the casing 3 delimiting the opening 31. In particular, the pressure drop generated is greater than the various frictions generated at the opening 31 and the portion of the cannula 50 arranged in the opening 31, namely here the first extreme portion 53a. This results in a partial, or even total, sealing of the opening 31 sufficient to allow the operation of the electric motor 4 and the suitable circulation of the cooling fluid FR.Due to the pressure drop observed at the outer surface 51b of the cannula 50, the cooling fluid FR circulating between the first circuit C1 and the second circuit C2, in particular under the effect of the pump, is essentially sent through the passage 52 of the cannula 50 then into the bore 45 of the shaft 41 and the leaks observed in the space present between the cannula 50 and the edges 32 of the opening 31 are minimized to an acceptable level, or even eliminated. By "essentially" is meant that more than 50%, or even 75% or even 90%, of the quantity of cooling fluid FR circulating at the opening 31 is directed through the passage 52 of the cannula 50. Such a principle makes it possible to ensure the sealing of the interface between the shaft 41 of rotor 42 and the casing 3 in a more compact and less expensive manner.

[0040] According to an exemplary embodiment illustrated in [Fig. 3] or 5, all or part of the plurality of grooves 54 extends parallel to each other. In particular, at least two grooves 54 of the plurality of grooves 54 are parallel to each other.

[0041] Additionally or alternatively, as illustrated in [Fig.4], all or part of the plurality of grooves 54 extends along a helical path relative to the first direction 100.

[0042] The grooves 54 may have a profile of variable shape. For example, the grooves 54 may have a flat bottom, as illustrated in [Fig. 3], curved or inclined, as shown in [Fig. 4]. Similarly, a top of a groove considered, corresponding to an area between the bottoms of two adjacent grooves 54 and at least partly in the continuity of the outer surface 51b of the cannula 50, may be flat, curved or inclined.

[0043] Optionally but preferably, all or part of the plurality of grooves 54 has a depth greater than or equal to 0.10 mm, as shown in [Fig. 5]. The depth of the grooves 54 is measured between the outer surface 51b of the cannula 50 and the bottom of the groove 54 considered along a direction transverse or orthogonal to the first direction 100. Particularly, as illustrated in [Fig. 3], all or part of the plurality of grooves 54 has a depth greater than or equal to 0.30 mm, or even 0.50 mm.

[0044] Optionally, the cannula 50, in particular the first extreme portion of the cannula 50, comprises at least one chamfer 55. For example, the free end of the cannula 50 is chamfered over all or part of a circumference bordering the passage 52. The presence of such a chamfer 55 advantageously makes it easier to insert the cannula 50 into the opening 31 when mounting the electric motor 4 within the gearbox 30.

[0045] Optionally again, the cannula 50 comprises at least one shoulder 53c arranged on all or part of the outer periphery of the cannula 50. For example, the shoulder 53c is arranged between the first end portion 53a and the second end portion 53b. It can be configured to be arranged in support of the first end 41a of the shaft 41, for indexing and / or stop purposes along the first direction 100. Also, the shoulder 53c can be configured to extend at least partly into a recess 33 of the gearbox casing 3 comprising the opening 31 and at least partly surrounding the latter. For example, such a recess 33 is formed by countersinking.

[0046] Thus, when the vehicle 1 is in operation, the cooling fluid FR circulates in the first circuit C1 so as to allow the heat treatment of the gearbox 30. At least a portion of the cooling fluid FR is extracted from the circuit, for example by means of the pump, and sent through the opening 31. The extracted cooling fluid FR then passes essentially through the passage 52 of the cannula 50 and is then sent through the bore 45, towards the second circuit C2. Optionally, a minimal portion of the cooling fluid FR passes between the outer surface 51b of the cannula 50 and the edges 32 of the opening 31.

[0047] The invention thus proposes an alternative to electric motors, in particular to electric motors integrated into a gearbox. The proposed solution is advantageously compact, simple to implement and inexpensive since it eliminates the need to integrate conventional seals, in particular high-speed rotary seals, and is integrated into the shaft of the electric motor. Furthermore, the invention can be extended to a wide range of electric motors.

[0048] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means or configuration and to any technically operative combination of such means insofar as they ultimately fulfill the functionalities described and illustrated in the present document.

Claims

Claims

1. Arrangement (2) for a motor vehicle (1) comprising: - a gearbox casing (3) (30) configured to allow the circulation of a cooling fluid (FR) at a first circuit (Cl) and comprising an opening (31), delimited by at least one edge (32) of the casing (3), in fluid connection with said circuit; - an electric motor (4) comprising a rotor shaft (41) (42) extending along a first direction (100) and comprising a bore (45) opening at a first end (41a) of the shaft (41) so as to allow a fluid connection between the first circuit (Cl) and at least a part of the electric motor (4);characterized in that the electric motor (4) comprises a sealing device (5) comprising a hollow cannula (50) arranged on the first end (41a) of the shaft (41) and configured to extend partly into the opening (31) in order to allow a fluid connection between the first circuit (Cl) and the shaft (41), an outer surface (51b) of the cannula (50) comprising a plurality of grooves (54) extending at least partly transversely to the first direction (100) and arranged opposite the at least one edge (32) of the opening (31).;

2. Arrangement (2) according to the preceding claim, in which the cannula (50) of the sealing device (5) is attached and mounted on the shaft (41).

3. Arrangement (2) according to one of the preceding claims, in which the cannula (50) of the sealing device (5) is made of a metallic material, such as steel or aluminum.

4. Arrangement (2) according to one of the preceding claims in which the plurality of grooves (54) comprises: - at least two grooves (54) parallel, or substantially parallel, to each other; and / or - at least one helical groove relative to the first direction (100).

5. Arrangement (2) according to one of the preceding claims, in which all or part of the plurality of grooves (54) has a depth, relative to the outer surface (51b) of the shaft (41), greater than or equal to 0.10 mm.

6. Arrangement (2) according to one of the preceding claims, in which a free end of the cannula (50) of the sealing device (5) comprises at least one chamfer (55).

7. Arrangement (2) according to one of the preceding claims, in which the cannula (50) comprises a shoulder (53c) configured to be arranged in support of the rotor shaft (41) (42) along the first direction (100) and / or configured to extend into a recess (33) of the casing (3) comprising the opening (31).

8. Arrangement (2) according to one of the preceding claims, wherein the bore (45) of the shaft (41) is defined by a first dimension along a direction orthogonal to the first direction (100): - the cannula (50) of the sealing device (5) being at least partly inserted into the bore (45); and / or - the hollow cannula (50) of the sealing device (5) being defined by a second dimension, defined at an inner surface (51a) of the cannula (50), opposite the outer surface (51b), strictly less than the first dimension of the shaft (41).

9. Electric motor (4) for an arrangement (2) according to one of the preceding claims, comprising: - a shaft (41) extending along a first direction (100) and comprising a bore (45) opening at a first end (41a) configured to allow a fluid connection with a cooling fluid circuit (FR) of a gearbox (30); and - a sealing device (5) comprising a hollow at least partly cylindrical cannula (50) arranged on the first end (41a) of the shaft (41) and configured to extend partly into an opening (31) of the gearbox (30) in order to allow a fluid connection between the circuit and the shaft (41), an outer surface (51b) of the cannula (50) comprising a plurality of grooves (54) extending at least partly along a direction transverse to the first direction (100).

10. Vehicle (1) with electric or hybrid motorization comprising an arrangement (2) according to one of claims 1 to 8 and / or an electric motor (4) according to claim 9.

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