Description:Complete specification: The following specification particularly describes the invention and the manner in which it is to be performed.
Field of the invention:
[0001] The present disclosure relates to an electric drive unit of a vehicle and a method for enclosing the same.

Background of the invention:
[0002] An electric drive unit is the primary driving unit for an electric vehicle, and it converts electrical energy into motion. An electric drive unit is also called an electric axle or an eAxle and it comprises three main components: an electrical machine, a power electronics unit, and a transmission. The components of the electric drive unit are assembled in a housing and enclosed with a cover. A cooling system is deployed in electric vehicles to keeps the temperature of the electric drive unit in the optimal conditions at certain pressure. The cooling system maintains the temperature in optimal condition using a coolant and internal cooling channel of the electric drive unit.

[0003] WO19154685 A1 discloses an electric drive unit for a motor vehicle, which has a vehicle cooling system, wherein the electric drive unit has an electric machine, a transmission operatively connected to the electric machine, and power electronics for controlling the electric machine, wherein the components of the electric drive unit, in the assembled state, form an integrated cooling system having a common cooling fluid inlet and a common cooling fluid outlet, wherein the integrated cooling system is connected to the one common cooling fluid inlet and to the one common cooling fluid outlet on a vehicle cooling system.

[0004] The housing for an electric drive unit can be made from a metal selected from Aluminum and the cover for enclosing the housing can be made from a metal selected from Aluminum or a non-metal selected from Plastic. The choice of material for the housing and the cover, and the manner of enclosing them poses various problems. The problem encountered while enclosing the aluminum housing with an aluminum cover using wet sealing is that it poses a higher probability of corrosion, and increased cost because of casting and machining of the aluminum cover. Whereas the problem encountered while enclosing the aluminum housing with a cover using solid seal is that it poses higher possibility of leakage, cooling system failure, and increased cost because of the complexity in manufacturing a profiled solid seal.

[0005] The present invention solves all the above-mentioned problems in a manner as described in the claims.

Brief description of the accompanying drawings:
[0006] An embodiment of the disclosure is described with reference to the following accompanying drawings.
[0007] Fig. 1 illustrates isometric view of an electric drive unit, according to an embodiment of the present invention;
[0008] Fig. 2 illustrates exploded view of an electric drive unit, according to an embodiment of the present invention;
[0009] Fig. 3 illustrates isometric view of a cover with an integrated coolant outlet, according to an embodiment of the present invention;
[0010] Fig. 4 illustrates top view of the backside of a cover, according to an embodiment of the present invention;
[0011] Fig. 5 illustrates top view of the geometry of a sealing surface of the housing and a sealant material dispensed on the sealing surface of the housing, according to an embodiment of the present invention; and
[0012] Fig. 6 illustrates a flow diagram of method for enclosing a housing of the electric drive unit with the cover, according to the present invention.

Detailed description of the embodiments:
[0013] Fig. 1 illustrates isometric view of an electric drive unit 100 along with its components, according to an embodiment of the present invention. The electric drive unit 100 of a vehicle comprises at least one electrical machine, at least one power electronics unit connected to said at least one electrical machine, at least one transmission coupled to said at least one electrical machine, and a housing 102 and a cover 104 enclosing the at least one electrical machine, the at least one power electronics unit, and the at least one transmission, characterized in that, the housing 102 is made of a first material, and the cover 104 is made of a second material.

[0014] In an embodiment of the present invention, the housing 102 of the electric drive unit 100 is made of a metal selected from Aluminum. Other metals known in the art are also usable as required. In another embodiment of the present invention, the cover 104 is made of a non-metal selected from a Plastic. In yet another embodiment of the present invention, the cover 104 is made of a polyamide plastic called PA66GF30.

[0015] In an embodiment of the present invention, the cover 104 is wet sealed with the housing 102. In another embodiment of the present invention, the cover 104 is wet sealed with the housing 102 using a silicone sealant material with a predetermined curing period of twenty minutes.

[0016] In an embodiment of the present invention, the housing 102 and the cover 104 have a crosshatch design to enhances wet sealing. In another embodiment of the present invention, the housing 102, and the cover 104 have at least one positioning holes to aid assembly of the cover 104 with the housing 102.

[0017] In an embodiment of the present invention, both the cover 104 and the housing 102 are pre-cleaned before wet sealing the cover 104 with the housing 102. In another embodiment of the present invention, the housing 102 is pre-cleaned by laser cleaning a sealing surface of the housing 102 before wet sealing the cover 104 with the housing 102. In yet another embodiment of the present invention, the cover 104 is pre-cleaned by plasma plus treating the cover 104 before wet sealing the cover 104 with the housing 102. Laser cleaning removes the unwanted matter from the sealing surface of the housing 102 by sweeping a laser beam across the sealing surface and vaporizing the contaminants. Plasma plus treatment cleans the cover 104 from contaminants, which may impede the wet sealing, using a plasma beam and enhances the adhesion.

[0018] Fig. 2 illustrates exploded view of the electric drive unit 100 and the manner of its assembly, according to an embodiment of the present invention. The Fig. 2 also illustrates the manner of assembly of the cover 104 with the housing 102 of the electric drive unit 100.

[0019] In an embodiment of the present invention, the cover 104 has an integrated coolant outlet 106 as illustrated in Fig. 1 and Fig. 3. The coolant outlet 106 is generally a separate component, but in the present invention the coolant outlet 106 and the cover 104 are made of a single unit/body, thereby reducing the number of components and the assembly steps. Fig. 4 illustrates top view of the backside of the cover 104 along with the integrated coolant outlet 106, according to an embodiment of the present invention. Fig. 5 illustrates top view of the geometry of the sealing surface of the housing 102 and a sealant material dispensed on the sealing surface of the housing 102, according to an embodiment of the present invention.

[0020] In an embodiment of the present invention, the electric drive unit 100 utilizes a coolant, which is a combination of water and glycol, under a pressure of 2.5 bar for cooling the electric drive unit 100. The electric drive unit 100, the housing 102, the cover 104, and the wet sealing between the housing 102 and the cover 104 can be designed to be operable with any coolant for any pressure range.

[0021] Fig. 6 illustrates a flow diagram of method for enclosing a housing 102 of an electric drive unit 100 with a cover 104, according to an embodiment of the present invention. The method for enclosing the housing 102 of the electric drive unit 100 with the cover 104 comprises a plurality of steps some of which are illustrated in Fig. 6 using blocks 602 to 608, according to the present invention. The step 602 comprises pre-cleaning the housing 102 and the cover 104 for enhanced wet sealing. The pre-cleaning of the housing 102 is done by laser cleaning the sealing surface of the housing 102. The pre-cleaning of the cover 104 is done by plasma plus treating the cover 104. The cover 104 comprises an integrated coolant outlet 106.

[0022] A step 604 comprises dispensing the sealant material on the sealing surface of the housing 102 according to the geometry of the sealing surface of the housing 102 for wet sealing the cover 104 with the housing 102. According to the method, the silicone sealant material is dispensed for wet sealing the cover 104 with the housing 102.

[0023] A step 606 comprises assembling the cover 104 with the housing 102 using at least one positioning holes on the housing 102 and the cover 104. A step 608 comprises screwing the cover 104 with the housing 102 within a predetermined curing period. In an embodiment of the present invention, the silicone sealant material is dispensed the predetermined curing period for which is twenty minutes, but not limited to the same.

[0024] According to the method, an air tightness test is conducted to check for leakages after wet sealing the cover 104 with the housing 102 of the electric drive unit 100.

[0025] According to the present invention, a plastic cover 104 with wet sealing for covering and sealing cooling system of the electric drive unit 100 of the vehicle is disclosed. The present invention solves the problems present in the state of art. In addition to this, the present invention by integrating coolant outlet 106 in the cover 104 saves the cost and separate assembly stage required for a cover made from a metal selected from Aluminum. Additionally, wet sealing the cover 104 with the housing 102 reduces the probability of corrosion, and avoids the complexity and cost related to solid sealing the cover and the housing of the electric drive unit 100.

[0026] It should be understood that the embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modification and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:
1. An electric drive unit (100) of a vehicle, said electric drive unit (100) comprises:
? at least one electrical machine;
? at least one power electronics unit connected to said at least one electrical machine;
? at least one transmission coupled to said at least one electrical machine; and
? a housing (102) and a cover (104) enclosing said at least one electrical machine, said at least one power electronics unit and said at least one transmission, characterized in that, said housing (102) is made of a first material and said cover (104) is made of a second material.

2. The electric drive unit (100) as claimed in claim 1, wherein said first material is a metal selected from Aluminum and said second material is a non-metal selected from a Plastic.

3. The electric drive unit (100) as claimed in claim 1, wherein said cover (104) is wet sealed with said housing (102).

4. The electric drive unit (100) as claimed in claim 3, wherein said cover (104) is wet sealed with said housing (102) using a silicone sealant material.

5. The electric drive unit (100) as claimed in claim 3, wherein said housing (102) and said cover (104) have a crosshatch design to enhance wet sealing.

6. The electric drive unit (100) as claimed in claim 3, wherein said housing (102) and said cover (104) are pre-cleaned before wet sealing by laser cleaning said housing (102) and plasma plus treating said cover (104).

7. The electric drive unit (100) as claimed in claim 1, wherein said cover (104) comprises an integrated coolant outlet (106).

8. A method for enclosing a housing (102) of an electric drive unit (100) with a cover (104), said method comprising the steps of:
? pre-cleaning said housing (102) and said cover (104), characterized by,
? dispensing a sealant material on a sealing surface of said housing (102) according to the geometry of said sealing surface of said housing (102) for wet sealing said cover (104) with said housing (102);
? assembling said cover (104) with said housing (102) using at least one positioning holes on said housing (102) and said cover (104); and
? screwing said cover (104) with said housing (102) within a predetermined curing period.

9. The method as claimed in claim 8, wherein a silicone sealant material is dispensed, wherein said predetermined curing period for which is twenty minutes.

10. The method as claimed in claim 8, wherein pre-cleaning of said housing (102) is done by laser cleaning said sealing surface of said housing (102) and plasma plus treating said cover (104).