VEHICLE ELECTRIC POWERTRAIN INCLUDING AN INVERTER AND A COOLING CIRCUIT

Abstract

A powertrain for an electric or hybrid vehicle comprising an electric machine (2) rotating about a principal axis of rotation (A), an inverter (8) fixed transversely flat to a front axial end of this machine (2), and a substantially rigid cooling fluid tube (12) for the powertrain disposed on the side of a housing of the machine (2), having an axially disposed front end sleeve that is fitted onto an end fitting fixed to the inverter (8), the end sleeve having a transverse rear support face disposed on a side of the housing of the electric machine (2) allowing access to this support face in a transverse direction. Figure 1

Description

Title of the invention: ELECTRIC VEHICLE POWERTRAIN COMPRISING AN INVERTER AND A COOLING CIRCUIT

[0001] The present invention relates to a motor vehicle powertrain comprising an electric machine, an inverter and a cooling circuit, as well as a method of assembling the powertrain and a motor vehicle equipped with this powertrain.

[0002] A known type of electric powertrain for motor vehicle traction, presented in particular by document FR-A1-3073686, comprises, along its axis of rotation, at one end of the machine a transmission driving the drive wheels of the vehicle, and at the other end an inverter forming a substantially flat housing which is fixed on the transverse face at the end of this machine. The inverter powered by the traction battery of the vehicle, is controlled by a control unit to deliver electrical power to the machine in the form of sinusoidal waves.

[0003] An intermediate plate arranged transversely between the electric machine and the inverter, comprises an extension projecting from the contour of this machine having an elastic connection for fixing the powertrain group.

[0004] A water-based heat transfer fluid circuit carrying out the heat exchanges of the powertrain, the electric machine and the passenger compartment of the vehicle in order to optimize the transfer of calories, is connected to an input and an output of the inverter to pass through it in order to evacuate the calories generated by the electrical losses of its components. In particular, the electric machine may comprise an internal cooling circuit using a lubricating oil, and a heat exchanger crossed by the heat transfer fluid to cool this oil.

[0005] Furthermore, the space available around the powertrain in the engine compartment of the vehicle, taking into account the movements of this group maintained by elastic vibration filtering connections, is often limited.

[0006] In particular, the space facing the front of the vehicle is limited by its front facade comprising the heat exchangers with the ambient air, which are arranged in a position imposed by the length of the overhang in front of the front wheels, depending on the silhouette of the vehicle. The axial space at the ends of the powertrain is limited by the proximity of the side members arranged opposite, on the sides of the engine compartment.

[0007] Generally speaking, it is known to fix on one side of the electrical machine, in a direction generally parallel to its axis, as close as possible to its main casing to limit the size, a substantially rigid cooling circuit tube having one end connected to the heat exchanger between the water and oil circuits, the other end arriving with an axial orientation on a male end of the inverter to be connected thereto.

[0008] To fit the tube onto the male end piece having interposed annular sealing gaskets, it is necessary to apply a sufficiently strong axial thrust to compress these gaskets in order to achieve the fitting onto this end piece. However, with the substantially rigid tube passing as close as possible to the casing of the electrical machine, an operator does not have the possibility of sliding his fingers behind it to grasp it with his full hand in order to apply the axial force necessary for its fitting onto the end piece of the inverter.

[0009] In addition, it would be possible to provide a shape for the tube which moves away from the casing of the electric machine to form a finger passage behind this tube allowing it to be grasped with the whole hand, but this results in an offset of the tube towards the front of the vehicle which poses problems of greater bulk for the powertrain.

[0010] The present invention aims in particular to avoid these problems of the prior art.

[0011] For this purpose, it offers an electric or hybrid vehicle powertrain comprising an electric machine rotating along a main axis of rotation, an inverter fixed transversely flat to a front axial end of this machine, and a substantially rigid tube of cooling fluid of the group arranged on the side of a casing of the machine, having a front end sleeve arranged axially which is fitted on an end piece fixed to the inverter, this power unit being remarkable in that the end sleeve comprises a transverse rear support face which is arranged on one side of the casing of the electric machine allowing access to this support face in a transverse direction.

[0012] An advantage of this power unit is that it allows, in a simple and rapid manner, to slide on the side of the casing in the transverse direction an axially blocked tool, coming onto the rear support face of the tube, to then carry out the assembly of the inverter by pushing it backwards which at the same time forcibly introduces its tip into the end of the tube which cannot move back. The introduction force including the compression of the seals is thus automatically taken up towards the rear by the axially blocked tool applying a reaction.

[0013] The electric or hybrid vehicle powertrain according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0014] Advantageously, the front end of the fluid tube has a shoulder of larger diameter than the tube having the rear support face at the rear.

[0015] Advantageously, the rear support face of the fluid tube is arranged in a housing of the casing surrounded by ribs.

[0016] In this case, the casing of the electrical machine may comprise two ribs arranged perpendicular to the axial direction, forming two sides of the housing, each comprising a bore receiving the front end of the fluid tube.

[0017] In addition, the casing of the electric machine may comprise two ribs arranged parallel to the axial direction, forming two other sides of the housing.

[0018] Advantageously, the fluid tube is fitted as closely as possible to the side of the machine casing along its path.

[0019] The invention also relates to a method for assembling a powertrain comprising any one of the preceding characteristics, remarkable in that it comprises a step of preparing a subassembly comprising the fluid tube fixed to the side of the casing of the electric machine, then a step of inserting in a transverse direction a fork blocked axially on the rear bearing face of the tube, then a step of axially pushing the inverter towards its mounting position on the casing of the electric machine.

[0020] The invention further relates to a workstation implementing an assembly method comprising the preceding characteristics, remarkable in that it comprises devices for positioning the electrical machine with the fluid tube fixed thereon, a tool for wedging the rear support face having a sliding in the transverse direction, and an assembly jack for applying an axial thrust to the inverter.

[0021] Advantageously, the wedging tool is fixed on a wedging cylinder comprising a movement in the transverse direction.

[0022] The invention further relates to a motor vehicle equipped with an electric traction powertrain comprising any one of the preceding characteristics, remarkable in that the main axis of the electric machine is arranged in the transverse direction of the vehicle.

[0023] The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description below given by way of example, with reference to the appended drawings in which:

[0024] [Fig-1] is an overview of a complete powertrain according to the invention

[0025] [Fig.2] is a detailed view of the main casing of the electric machine of this group at the front end of the tube;

[0026] [Fig.3] is an axial sectional view of the end of this tube arranged in its environment; and

[0027] [Fig.4] is a view of an inverter assembly station on the electrical machine of this powertrain.

[0028] [Fig. 1] shows a powertrain comprising an electric machine 2 rotating along a main axis A, receiving on a rear axial side a transmission to the drive wheels 4, above a group control computer 6, and on its front end transverse face a flat inverter 8.

[0029] The powertrain comprises on a lateral face facing the front of the vehicle, next to the transmission 4, a heat exchanger 10 transmitting the calories transported by an oil of the electric machine 2 for its cooling, to a water circuit which manages the thermal of all the functions of the vehicle.

[0030] A tube of the water circuit 12 made of a rigid plastic material, starting from the heat exchanger 10 to run along the lateral side of the electrical machine 2, has its front end, aligned in the axial direction, which passes into a housing 16 formed on the casing of this machine. This front end is connected to a pipe of the inverter 14 fixed on the side of this inverter 8 in order to supply it with heat transfer fluid.

[0031] Figures 2 and 3 show the casing of the electrical machine 2 formed by a casting of aluminum alloy, comprising at the level of the front end of the tube of the water circuit 12 aligned along an axis B, the housing 16 of substantially square section framed by stiffening ribs of the casing comprising two horizontal ribs 22 arranged along an axial plane and two vertical ribs 24 arranged along a transverse plane. The two vertical ribs 24 comprise a bore 26 aligned along the axis B, allowing the passage of the front end of the tube 12.

[0032] The pipe of the inverter 14 comprises an end piece 34 aligned along the axis B, comprising on its contour two elastic O-rings 36 which are held in circular grooves of this end piece. The front end of the tube 12 forms a sleeve 30 of larger diameter than the tube, inserted into the holes of the casing 26, having a cylindrical bore which fits onto the end piece of the pipe 34 by tightening the O-rings 36 to ensure a seal.

[0033] The sleeve 30 arranged between the two vertical ribs 24, has towards the rear an annular transverse support face 32 arranged inside the housing of the casing 16 completely open on the side, towards the front of the vehicle, which gives access in the transverse direction to this support face allowing the insertion in this direction of a tool blocking the recoil of the sleeve.

[0034] [Fig. 4] shows a workstation comprising a base 40 having vertical supports 42 for positioning and holding the powertrain comprising the electric machine 2 with its transmission 4.

[0035] A first assembly jack 44 fixed on the base 40, arranged parallel to the main axis of the electrical machine A, has at the end of its rod a plate 46 receiving by axially oriented pins 48 the inverter 8 which is aligned on its final position, set back from the bearing face on the electrical machine 2.

[0036] A second rear wedging cylinder 52 arranged perpendicular to the main axis A, comprises at the end of its rod a fork 50 which can advance in a transverse direction to be inserted into the housing of the casing 16, just behind the rear support face 32 of the sleeve 30 of the cooling fluid tube 12.

[0037] The method of assembling the powertrain is as follows, from a workstation comprising the two jacks 44, 52 which are retracted. The subassembly comprising the assembly of the electric machine 2 and the transmission 4, on the side of which the heat exchanger 10 and the fluid tube 12 have been fixed, is positioned on the vertical supports 42 of the base 40 of the workstation. The inverter 8 is positioned and held by the pins 48 on the plate 46 of the assembly jack 44.

[0038] In a following operation, the rear wedging cylinder 52 is actuated to engage, in the transverse direction, its vertically oriented fork 50 in the housing of the electric machine casing 16 in order to come into contact with the rear bearing face 32 of the sleeve of the fluid tube 30. The wedging cylinder 52 thus produces, by its axially wedged fork 50, a rear stop for the sleeve 30 which cannot move back. In particular, the fork 50 can be adjusted between the annular rear bearing face of the sleeve 32 and the vertical rib 24 arranged just behind it, forming a reaction support.

[0039] In a following operation the assembly jack 44 is actuated to advance the inverter 8 which fits on the front face of the electrical machine 2. At the same time the end piece 34 of the pipe 14 fixed on the inverter 8 advances along the axis B to enter the sleeve 30 of the fluid tube 12. With the force developed by the assembly jack 44, pressure is obtained from the end piece 34 fixed on the inverter 8, on the sleeve 30 which cannot move back thanks to the rear wedging fork 50, compressing the seals 36 of this end piece, to achieve its complete introduction in the final position in this sleeve.

[0040] In a following operation the inverter 8 is fixed on the casing of the electric machine 2. The rods of the two jacks 44, 52 are retracted, which clears the space around the power unit which is removed from the work surface.

[0041] The sleeve 30 of the tube, which can be fixed as close as possible to the casing of the electrical machine 2, is held in position in a simple and effective manner without manual intervention on the fluid tube 12. The operation of assembling the inverter 8, including the connection of the fluid pipes, is carried out in an ergonomic and safe manner. The powertrain comprising the fluid tube 12 adjusted as close as possible to the casing of the machine 2 is compact.

Claims

Claims

1. Powertrain of an electric or hybrid vehicle comprising an electric machine (2) rotating along a main axis of rotation (A), an inverter (8) fixed transversely flat to a front axial end of this machine (2), and a substantially rigid tube (12) of cooling fluid for the group arranged on the side of a casing of the machine (2), having a front end sleeve (30) arranged axially which is fitted onto an end piece (34) fixed to the inverter (8), characterized in that the end sleeve (30) comprises a transverse rear bearing face (32) which is arranged on one side of the casing of the electric machine (2) allowing access to this bearing face (32) in a transverse direction.

2. Power unit according to claim 1, characterized in that the rear support face (32) of the fluid tube (12) is arranged in a housing of the casing (16) surrounded by ribs (22, 24).

3. Powertrain according to claim 2, characterized in that the casing of the electric machine (2) comprises two ribs arranged perpendicularly (24) to the axial direction (A), forming two sides of the housing (16), each comprising a bore (26) receiving the front end of the fluid tube (12).

4. Power unit according to claim 3, characterized in that the casing of the electric machine (2) comprises two ribs arranged parallel (22) to the axial direction (A), forming two other sides of the housing (16).

5. A powertrain according to any preceding claim, characterized in that the fluid tube (12) is fitted as closely as possible to the side of the machine casing (2) along its path.

6. Method for assembling a powertrain according to any one of the preceding claims, characterized in that it comprises a step of preparing a subassembly comprising the fluid tube (12) fixed on the side of the casing of the electric machine (2), then a step of inserting in a transverse direction an axially locked fork (50) on the rear bearing face (32) of the tube (12), then a step of axially pushing the inverter (8) towards its mounting position on the casing of the electric machine (2).

7. Workstation implementing an assembly method according to claim 6, characterized in that it comprises positioning devices operation (42) of the electric machine (2) with the fluid tube (12) fixed thereon, a wedging tool (50) of the rear support face (32) having a sliding in the transverse direction, and an assembly jack (44) for applying an axial thrust on the inverter (8).

8. Workstation according to claim 7, characterized in that the wedging tool (50) is fixed on a wedging cylinder (52) comprising a movement in the transverse direction.

9. Motor vehicle equipped with an electric traction powertrain according to any one of claims 1 to 5, characterized in that the main axis (A) of the electric machine (2) is arranged in the transverse direction of the vehicle.

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