ELECTRIC VEHICLE POWERTRAIN ASSEMBLY WITH A REDUCER DRIVE BELT

Abstract

Electric vehicle powertrain comprising an electric traction machine directly mounted on top of a speed reducer (2), driving an input shaft (6) of this reducer (2) via a drive belt, the speed reducer (2) comprising a housing made of a metal casting containing an output differential (4) connected to the input shaft (6) by gears, this housing of the reducer (2) comprising an integrated linkage (20) from the same casting, disposed on the side of the electric machine and extending along the height of this machine, which has at its end elastic links (26) for attachment to the vehicle. Figure 2

Description

Title of the invention: ELECTRIC VEHICLE POWER UNIT COMPRISING A REDUCER DRIVE BELT

[0001] The present invention relates to an electric vehicle powertrain comprising a drive belt connecting the electric machine to a speed reducer, as well as an electric vehicle equipped with such a powertrain.

[0002] A known type of electric vehicle, presented in particular by document FR-Al-3019131, comprises a chassis made with tubes, fixed to the body of the vehicle, receiving by supports an electric powertrain suspended below comprising an electric machine, a speed reducer and an output differential.

[0003] In this way the chassis rigidly fixed to the body of the vehicle forms a resistant structure supporting the powertrain, generally by means of elastic elements, in order to support the mass of this group, to balance the reaction torque opposite to that which it applies on the drive wheels, and to filter the vibrations which it produces in order to avoid transmitting them to the body and generating noise.

[0004] Furthermore, a known type of electric vehicle powertrain, described in particular by document FR-A1-3102430, comprises an electric machine which drives, via a transmission belt, a driven pulley fixed to an input shaft of a speed reducer, thereby performing a first reduction in the rotational speed of this machine. The reducer housing includes a differential driving the vehicle's drive wheels.

[0005] A cover protects the drive belt to reduce the noise emitted by the drive belt during its operation.

[0006] It is known to produce this type of powertrain with transmission belt, comprising the electric machine fixed to the speed reducer, in the form of a sub-assembly which is suspended by means of elastic elements under a chassis of the vehicle body.

[0007] In particular, the electric machine can be attached to the speed reducer above the input shaft of this reducer, which is arranged along the transverse direction of the vehicle and has at one end the driven pulley for the drive belt. The input shaft, in turn, drives the output differential via gears. This differential is arranged in a substantially horizontal plane on the side of the shaft. A compact powertrain assembly is thus obtained.

[0008] In this case, it is known to produce a generally flat and vertical suspension structure for the powertrain, positioned next to the electric machine parallel to its shaft, extending over the height of this machine. This suspension structure is fixed to the top of the gearbox housing, in close alignment with the axis of the output differential.

[0009] The flat suspension structure comprises, in its upper part, two widely spaced rings aligned along the transverse direction, receiving within them elastic elements fixed by screws to the vehicle chassis. This structure comprises, in its lower part, a connecting device which is fixed to the top of the gearbox housing.

[0010] The added suspension structure then forms an added element on the reducer which can cause problems in maintaining the connection between the reducer and this structure, due in particular to the mass of the powertrain and the mechanical stresses and vibrations that it generates in operation.

[0011] In addition, the added suspension structure entails assembly time for this structure on the reducer with labor costs, and costs for supplying and managing the structure and the screwing elements on the reducer.

[0012] The present invention is specifically intended to avoid these problems of the prior art.

[0013] For this purpose, it proposes an electric vehicle powertrain comprising an electric traction machine directly fixed on top of a speed reducer, driving an input shaft of this reducer by a drive belt, the speed reducer comprising a casing made by a metal casting containing an output differential connected to the input shaft by gears, this powertrain being remarkable in that the casing of the reducer has an integrated link coming from the same casting, disposed on the side of the electric machine and extending along the height of this machine, which has at its end elastic links for fixing to the vehicle.

[0014] An advantage of this powertrain is that with the molding of the gearbox housing, the integrated connection in this housing is obtained at the same time, which allows the entire powertrain, including the gearbox and the electric machine attached to it, to be suspended directly under the vehicle chassis without any added intermediate part.

[0015] This secures the connection between the gearbox and the powertrain, formed directly by molding the gearbox housing, which ensures high rigidity and eliminates the risk of failure of a fastener on the housing. Furthermore, by eliminating the need to assemble an intermediate connection on the gearbox housing, labor time and the number of components are reduced, thus lowering costs.

[0016] The powertrain according to the invention may further comprise one or more the following characteristics, which can be combined with each other.

[0017] In particular, the integrated link can be arranged above the differential.

[0018] Advantageously, the integrated link has an overall flat shape which is parallel to the axis of the electric machine.

[0019] In this case, advantageously the integrated link comprises an elongated, substantially parallelepiped-shaped base which forms an upward extension of the reducer housing.

[0020] Advantageously, the elongated base has at each end a connecting arm with the vehicle body.

[0021] In this case, advantageously each arm terminates in a ring containing an elastic link.

[0022] Advantageously, the two rings have aligned axes which are arranged along the transverse direction of the vehicle.

[0023] Advantageously, each arm has on one side facing outwards of the integrated link lugs for fixing a protective cover.

[0024] The invention also relates to an electric motor vehicle equipped with a powertrain comprising any one of the preceding characteristics, remarkable in that the electric machine has an axis arranged along the transverse direction of this vehicle.

[0025] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0026] [Fig. 1] is a diagram showing a side view of the powertrain according to the invention;

[0027] [Fig.2] is a view of the left side of this powertrain; and

[0028] [Fig.3] is a view of the right side of this powertrain.

[0029] Throughout the document the upper or top side relates to an electric vehicle placed on a horizontal ground, the transverse direction is defined with respect to the longitudinal axis of the vehicle.

[0030] Figures 1, 2 and 3 show a speed reducer 2 comprising a housing made by casting in aluminium alloy, containing an output differential 4 connected by wheel shafts not shown to the drive wheels of the vehicle, and in the same substantially horizontal plane an input shaft 6 which is connected to this differential by internal gears.

[0031] The shafts of the reducer 2 are arranged along the transverse direction of the vehicle, the rear direction of this vehicle along its longitudinal axis is shown by an arrow AR.

[0032] An electric machine 10 working in traction from energy delivered by a traction battery, or a generator to recharge this battery, is directly fixed to the gearbox housing by means of a first hole 30 and a second oblong hole 32 in the gearbox housing.

[0033] The electric machine 10 having an axis arranged substantially vertically above the input shaft 6, includes a drive pulley 12 which is connected to a driven pulley 16 of this input shaft by a flat belt 14 having a series of triangular ribs fitting onto complementary grooves of the pulleys to increase grip.

[0034] The tension of the belt 14 is achieved by pivoting the electric machine 10 around the first hole in the housing 30, with a screw sliding in the second oblong hole 32 to ensure this adjustment.

[0035] The housing of the reducer 2 has in front of the electric machine 10 an integrated link 20 obtained directly by the metal molding of this housing, in the same material, having a generally flat, substantially vertical shape, which is arranged parallel to the shaft of the electric machine 10.

[0036] The integrated link 20 comprises a massive, elongated, substantially parallelepiped-shaped base 22, forming an outgrowth of the gearbox housing 2, extending upwards at each end by a rising arm 24 which terminates in a ring 26 having a transversely arranged axis B. Each arm 24 is framed by ribs to ensure its rigidity.

[0037] Each ring 26 receives an elastomer block having an axial hole that allows direct attachment to the chassis of the vehicle 28, in order to filter vibrations generated by the powertrain. The spacing between the two rings 26 provides stability to the powertrain around the axis B of these rings. A torque reaction link, not shown, connects the reduction gear 2 to the vehicle chassis to counteract the torque it transmits to the drive wheels.

[0038] Each rising arm 24 has, on the outside of the integrated link 20, an angled leg 28 ending in an elongated part parallel to the longitudinal axis A, comprising a hole.

[0039] A protective sheet metal cover, not shown, is fixed to each side of the powertrain, and is screwed directly onto the gearbox housing using the holes in the angled tabs 28 arranged on a rigid support, the integrated link 20 formed by the molding of the gearbox housing 2. In particular, one of the protective covers covers the transmission belt 14 and the pulleys 12, 16 to protect them.

[0040] The powertrain forms a compact unit, including the integrated link 20 which is highly rigid and perfectly reliable over the life of the vehicle.

Claims

Claims

1. Electric vehicle powertrain comprising an electric traction machine (10) directly fixed on a top of a speed reducer (2), driving an input shaft (6) of this reducer (2) by a drive belt (14), the speed reducer (2) comprising a casing made by a metal casting containing an output differential (4) connected to the input shaft (6) by gears, characterized in that the casing of the reducer (2) comprises an integrated connection (20) coming from the same casting, arranged on the side of the electric machine (10) and extending along the height of this machine (10), which has at its end elastic connections (26) for fixing to the vehicle.

2. Powertrain according to claim 1, characterized in that the integrated link (20) is arranged above the differential (4).

3. Powertrain according to claim 1 or 2, characterized in that the integrated connection has a generally flat shape which is parallel to the axis of the electric machine (10).

4. Powertrain according to claim 3, characterized in that the integrated connection (20) comprises an elongated, substantially parallelepiped base (22) which forms an upward extension of the gearbox casing (2).

5. Powertrain according to claim 4, characterized in that the elongated base (22) comprises at each end an arm (24) for connection with the body of the vehicle.

6. Powertrain according to claim 5, characterized in that each arm (24) ends in a ring containing an elastic connection (26).

7. Powertrain according to claim 6, characterized in that the two rings (26) have aligned axes which are arranged parallel to the axis of the electric machine (10).

8. Powertrain according to any one of claims 5 to 7, characterized in that each arm (24) comprises on one side facing the outside of the integrated connection (20), fixing lugs for a protective cover (24).

9. Electric motor vehicle equipped with a powertrain according to any one of the preceding claims, characterized in that the electric machine (10) has an axis arranged along the transverse direction of this vehicle.

Images