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 for a vehicle, and particularly to an electric drive unit with an integrated mechanical disconnect.

Background of the invention:
[0002] Electric vehicles (EVs), powered by electricity stored in the batteries, provide a sustainable and environment friendly solution to the transport problem. But EVs pose their own problems. One such problem is faced when an EV breaks down and it is to be towed/pulled using a hook/chain or a dolly or a wheel lift attachment connected to a towing vehicle.

[0003] The problem faced while towing/pulling of the EVs is that the wheel rotation during the towing/pulling of the broken-down EV generates power and to be specific electromotive force (EMF) in the electric machine. The EMF is generated as the wheel rotation translates into rotation of the motor shaft of the electric machine due to engagement of the electric machine with the wheels through the transmission. This generated EMF during towing/pulling or when the EV is not in operation could burn the windings of the electric machine and damage the electric machine. A solution to prevent this EMF is to tow the broken-down EV on a flatbed tow truck. But these flatbed tow trucks are not easily accessible and are not everywhere available.

[0004] US11933370 BB discloses methods and systems for a vehicle transmission. The vehicle transmission includes an input interface configured to mechanically couple to a motive power source. The vehicle transmission further includes a first disconnect device releasably mechanically coupling a first output to a first drive axle and a second disconnect device releasably mechanically coupling a second output to a second drive axle.

[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 a block diagram of an electric drive unit for a vehicle, according to an embodiment of the present invention;
[0008] Fig. 2 illustrates an exploded view of the electric drive unit, according to an embodiment of the present invention, and
[0009] Fig. 3 illustrates three diagrams (A, B, C) representing stages of a connector shaft disengaging at least one transmission from at least one electrical machine, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0010] Fig. 1 illustrates a block diagram of an electric drive unit for a vehicle, according to an embodiment of the present invention. The electric drive unit 100 comprises at least one electrical machine 102 with a motor shaft 1021, at least one transmission 104 with an input shaft 1041 engageable with the motor shaft 1021, characterized in that, the input shaft 1041 comprises a through bore and accommodates a connector shaft 106 therein, the connector shaft 106 is axially slidable in and out of the input shaft 1041 in a manner to engage and disengage the at least one transmission 104 with the at least one electrical machine 102. The connector shaft 106 comprises splines on its outer surface to mate with the grooves of the motor shaft 1021 and the input shaft 1041. The connector shaft 106 further comprises a tail end 1061 to engage with the motor shaft 1021 and thereby couple the motor shaft 1021 with the input shaft 1041.

[0011] In an embodiment of the present invention, the input shaft 1041 is a hollow tube with a first opening 10411 and a second opening 10412. The slidable movement of the connector shaft 106 is performed through the first opening 10411, and engagement with the motor shaft 1021 is done through the second opening 10412. In another embodiment of the present invention, the input shaft 1041 comprises splines 1042 on its outer surface to translate rotating force of the at least one electrical machine 102 to the internal components of the at least one transmission 104.

[0012] Fig. 2 illustrates an exploded view of the electric drive unit, according to an embodiment of the present invention. A cover/cap 108 is fixable on the at least one transmission 104 to secure the connector shaft 106 inside the input shaft 1041. The cover/cap 108 is fixable on the at least one transmission 104 using at least one of screws, nuts, bolts, fasteners or the like. The cover/cap 108 is removable to disengage the at least one transmission 104 from the at least one electrical machine 102 for situations like towing/pulling of a broken-down EV, manual service disconnect or the like. The embodiment of the present invention illustrated in Fig. 2 is non-limiting and other embodiments of the at least one transmission 104, the at least one electrical machine 102 and the connector shaft 106 can be used in the present invention.

[0013] In an embodiment of the present invention, the input shaft 1041 comprises grooves on its internal hollow surface of the through bore to mate with splines of the connector shaft 106. In another embodiment of the present invention, the motor shaft 1021 has a cavity, the cavity in the motor shaft 1021 comprises internal grooves to mate with splines of the connector shaft 106. The connector shaft 106 slides through the first opening 10411 and the second opening 10412 to engage with the cavity of the motor shaft 1021. The splines of the connector shaft 106 during sliding in and out of the motor shaft 1021 through the first opening 10411 the second opening 10412 mate with the interval grooves of the input shaft 1041 and the motor shaft 1021. The mating of the internal grooves of the input shaft 1041 and the motor shaft 1021 with the splines of the connector shaft 106 couples the connector shaft 106 with the input shaft 1041 and the motor shaft 1021.

[0014] In an embodiment of the present invention, the connector shaft 106 axially slides through the first opening 10411 and the second opening 10412 to couple the input shaft 1041 with the motor shaft 1021 and engage the at least one transmission 104 with the at least one electrical machine 102. Once the at least one transmission 104 and the at least one electrical machine 102 are engaged the rotational force of the at least one electrical machine 102 is transferred to the at least one transmission 104 and then to the wheels of the vehicle. In another embodiment of the present invention, the at least one transmission 104 is connected to an axle to transfer the rotational force of the at least one electrical machine 102 to the wheels of the EV.

[0015] In an embodiment of the present invention, the connector shaft 106 axially slides out of the second opening 10412 to decouple the input shaft 1041 from the motor shaft 1021 and disengage the at least one transmission 104 from the at least one electrical machine 102. Once the at least one transmission 104 and the at least one electrical machine 102 are disengaged no rotational force from the at least one transmission 104, received from the wheel rotation during the towing/pulling, is transferred to the at least one electrical machine 102. The disengagement of the at least one electrical machine 102 from the at least one transmission 104 isolates the at least one electrical machine 102 and thus the EV can be safely towed/pulled. Therefore, as per the present invention during the towing/pulling of the broken-down EV the at least one electrical machine 102 is isolated to prevent burning of the windings of the at least one electrical machine 102 from the EMF generated by the wheel rotation.

[0016] In an embodiment of the present invention, the connector shaft 106 comprises a hole 110 to accommodate a holding pin 112 to maintain disengaged state of the at least one transmission 104 from the at least one electrical machine 102.

[0017] Fig. 3 illustrates three diagrams (A, B, C) representing stages of a connector shaft disengaging at least one transmission from at least one electrical machine, according to an embodiment of the present invention. The diagram A represents the at least one transmission 104 engaged with the at least one electrical machine 102 through the connector shaft 106. The diagram B represents the cover 108 removed and the connector shaft 106 being slid out of the motor shaft 1021 and the second opening 10412 to disengage the at least one transmission 104 from the at least one electrical machine 102. The diagram C represent the connector shaft 106 completely slid out from the motor shaft 1021 and the second opening 10412, the at least one transmission 104 completely disengaged from the at least one electrical machine 102 and the holding pin 112 inserted into the hole 110 to maintain the disengaged state of the at least one transmission 104 from the at least one electrical machine 102. The embodiments of the present invention illustrated in Fig.3 highlight the splines (1042) on the outer surface of the input shaft 1041 described above.

[0018] As per the present invention, when an EV breaks down and it is to be towed/pulled the towing personnel or the driver removes the cover/cap 108 from the at least one transmission 104. Once the cover/cap 108 is removed, the towing personnel or the driver pulls the connector shaft 106 to slide it out of the motor shaft 1021 and the second opening 10412 for completely disengaging the at least one transmission 104 from the at least one electrical machine 102. Once the at least one electrical machine 102 is isolated, the holding pin 112 is inserted in the hole 110 to maintain disengaged state of the at least one transmission 104 from the at least one electrical machine 102. After performing the above steps, the broken-down EV could be towed/pulled in any manner using a hook/chain or a dolly or a wheel lift attachment connected to a towing vehicle. The above-mentioned steps could be followed for a manual service disconnect as well.

[0019] According to the present invention, the electric drive unit 100 for a vehicle is disclosed. The present invention solves the problem of not requiring a flatbed tow truck to tow/pull a broken-down EV. The present invention solves the above problem using a mechanical disconnect, the connector shaft 106, to disengage the at least one transmission 104 from the at least one electrical machine 102. Once the at least one transmission 104 and the at least one electrical machine 102 are disengaged the broken-down EV can be towed/pulled in any manner using a hook/chain or a dolly or a wheel lift attachment connected to a towing vehicle. As the at least one electrical machine 102 is isolated from the at least one transmission 104 during disengagement, the wheel rotation force generated during towing/pulling is not transferred to the at least one electrical machine 102 and thus no EMF is generated in the at least one electrical machine 102. The present invention provides a novel electric drive unit with an integrated mechanical disconnect which can be accessed by removing the cover. The advantage of the present invention is that it can be implemented across the vehicle segments irrespective of axles. Also, as the disconnect is mechanical and not electrical or electro-mechanical thus the disengagement mechanism is simple, and the EV is not required to be kept ON during the towing/pulling operation.

[0020] 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) for a vehicle, said electric drive unit (100) comprises:
? at least one electrical machine (102) with a motor shaft (1021);
? at least one transmission (104) with an input shaft (1041) engageable with said motor shaft (1021), characterized in that, said input shaft (1041) comprises a through bore and accommodates a connector shaft (106) therein, said connector shaft (106) is axially slidable in and out of said input shaft (1041) in a manner to engage and disengage said at least one transmission (104) with said at least one electrical machine (102).

2. The electric drive unit (100) as claimed in claim 1, wherein said connector shaft (106) comprises splines on outer surface, and a tail end (1061) of said connector shaft (106) engages with said motor shaft (1021) and thereby couples said motor shaft (1021) with said input shaft (1041).

3. The electric drive unit (100) as claimed in claim 1, wherein said input shaft (1041) comprises a first opening (10411) and a second opening (10412), wherein slidable movement of said connector shaft (106) is performed through said first opening (10411), and engagement with said motor shaft (1021) is done through said second opening (10412).

4. The electric drive unit (100) as claimed in claim 3, wherein said input shaft (1041) comprises grooves on internal hollow surface of said through bore to mate with splines of said connector shaft (106).

5. The electric drive unit (100) as claimed in claim 3, wherein said input shaft (1041) comprises splines (1042) on outer surface.

6. The electric drive unit (100) as claimed in claim 2, wherein said tail end (1061) of said connector shaft (106) engages with a cavity in said motor shaft (1021), wherein said cavity comprises internal grooves to mate with splines of said connector shaft (106).

7. The electric drive unit (100) as claimed in claim 1, wherein said connector shaft (106) axially slides through said first opening (10411) and said second opening (10412) to couple said input shaft (1041) with said motor shaft (1021) and engage said at least one transmission (104) with said at least one electrical machine (102).

8. The electric drive unit (100) as claimed in claim 1, wherein said connector shaft (106) axially slides out of said second opening (10412) to decouple said input shaft (1041) from said motor shaft (1021) and disengage said at least one transmission (104) from said at least one electrical machine (102).

9. The electric drive unit (100) as claimed in claim 1, wherein a cover (108) is fixable on said at least one transmission (104) to secure said connector shaft (106) inside said input shaft (1041).

10. The electric drive unit (100) as claimed in claim 1, wherein said connector shaft (106) comprises a hole (110) to accommodate a holding pin (112) to maintain disengaged state of said at least one transmission (104) from said at least one electrical machine (102).