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, and particularly to an electric drive unit with an integrated cooling arrangement.

Background of the invention:
[0002] An electric drive unit is the primary driving unit for an electric vehicle, and it converts electrical energy stored in batteries into motion of the vehicle. An electric drive unit, also called an electric axle or an eAxle, comprises three main components: a power electronics unit, an electrical machine, and a transmission. The power electronics unit translates electrical energy stored in batteries into power for driving the electrical machine. The electrical machine translates the electrical power fed through the power electronics unit into rotation of the electrical machine. The transmission translates the rotation of the electrical machine into motion of the vehicle at various speeds.

[0003] The above-mentioned conversions of energy in the electrical drive unit are imperfect, resulting in power losses, and causes heating of the components of the electrical drive unit. This heating of the components of the electrical drive unit requires their respective cooling. The power electronics unit is usually cooled by circulating water as a coolant using an external pump. The electrical machine is usually cooled by circulating oil as a coolant using an external pump or a gear wheel coupled with the rotor shaft of the electrical machine for splashing the coolant radially. The transmission is usually cooled by circulating the oil, lubricating it, as a coolant using the gear wheels present in the transmission.

[0004] The cooling of the electrical machine using oil as a coolant poses problems. The problem posed while cooling the electrical machine using an external pump to circulate oil is that it increases the total cost because an external pump along with its accessories is required. Whereas the problem posed while cooling the electrical machine using a gear wheel to circulate oil is that at low-speed operating region of the electrical machine there is inefficient cooling because of slower rotations.

[0005] DE102018213394 A1 discloses a cooling device (1) for an electrical axis (4) of a hybrid or electric vehicle having a pump assembly (24) with a first pump connected by a common shaft (26) (28) and a second pump (30), wherein the first pump (28) is configured to supply a coolant volume flow (V) of the first coolant circuit (10), wherein the second pump (30) is configured to supply a coolant volume flow (V) of the second coolant circuit (16), and wherein the electric machine (29) using the at least one temperature sensor (22a, 22b, 22c, 22d) sensed temperature (T, T, T, T) can be controlled. The invention further relates to an electrical axis (4) of a hybrid or electric vehicle. Moreover, the invention relates to a method for driving a pump assembly of a coolant circuit for an electric axis (4) of a hybrid or electric vehicle.

[0006] The present invention solves all the above-mentioned problems in a manner as described in the claims.

Brief description of the accompanying drawings:
[0007] An embodiment of the disclosure is described with reference to the following accompanying drawings.
[0008] Fig. 1 illustrates block diagram of an electric drive unit with a rotary structure in fluid communication with a first cooling channel, according to an embodiment of the present invention;
[0009] Fig. 2 illustrates block diagram of an electric drive unit with a rotary structure mechanically coupled to an impeller for circulation of a second coolant in a second cooling channel, according to an embodiment of the present invention;
[0010] Fig. 3 illustrates block diagram of an electric drive unit with a rotary structure mechanically coupled to a centrifugal disc, according to an embodiment of the present invention;
[0011] Fig. 4 illustrates block diagram of an electric drive unit with a pair of rotary structures mechanically coupled to two centrifugal discs respectively, according to an embodiment of the present invention; and
[0012] Fig. 5 illustrates block diagram of an electric drive unit with a pair of rotary structure mechanically coupled to two impellers respectively for circulation of a second coolant in a second cooling channel, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0013] Fig. 1 illustrates block diagram of an electric drive unit 100 with a rotary structure 120 in fluid communication with a first cooling channel 108, according to an embodiment of the present invention. The electric drive unit 100 with a rotary structure 120 is in fluid communication with the first cooling channel 108 for circulation of a second coolant in a second cooling channel 110. The electric drive unit 100 of the vehicle comprises at least one electrical machine 104, at least one power electronics unit 102 electronically/electrically connected to the at least one electrical machine 104, at least one transmission 106 mechanically coupled to the at least one electrical machine 104. The electric drive unit 100 further comprises the first cooling channel 108 arranged around and to cool the at least one power electronics unit 102 with a first coolant. A housing of the electric drive unit 100 encloses the at least one electrical machine 104, the at least one power electronics unit 102, the at least one transmission 106, the first cooling channel 108, characterized in that, the at least one rotary structure 120, comprising a turbine 112 with an axial output shaft 114, arranged in the housing and in fluid communication with the first cooling channel 108 in such a manner that the turbine 112 with the axial output shaft 114 is rotated by a flow of the first coolant, and rotation of the turbine 112 is translated to a circulation of the second coolant using the axial output shaft 114 for cooling the at least one electrical machine 104. The electric drive unit 100 is also referred to as an electric axle or an eAxle.

[0014] In an embodiment of the present invention, the first cooling channel 108 is a water jacket surrounding the at least one power electronics unit 102. In another embodiment of the present invention, the first cooling channel 108 is connectable to an external pump for circulation of the first coolant in the first cooling channel 108. In yet another embodiment of the present invention, the second coolant is circulated in at least one of the second cooling channel 110 of the at least one electrical machine 104 and within/in an enclosure of the at least one electrical machine 104. In yet another embodiment of the present invention, the axial output shaft 114 of the at least one rotary structure 120 is mechanically coupled with at least one of at least one impeller 202 (shown in Fig. 2) and at least one centrifugal disc 302 (shown in Fig. 3) for circulation of the second coolant. In yet another embodiment of the present invention, the first coolant is water and the second coolant is oil.

[0015] Fig. 2 illustrates block diagram of the electric drive unit 200 with the rotary structure 120 mechanically coupled to the impeller 202 for circulation of the second coolant in the second cooling channel 110, according to an embodiment of the present invention. The rotation of the axial output shaft 114 of the at least one rotary structure 120 rotates the impeller 202 for circulation of the second coolant in the second cooling channel 110 of the at least one electrical machine 104. The second cooling channel 110 is designed around the at least one electrical machine 104 in a loop. However, the second cooling channel 110 is shown as a simple loop just for easier understanding.

[0016] Fig. 3 illustrates block diagram of the electric drive unit 300 with the rotary structure 120 mechanically coupled to the centrifugal disc 302, according to an embodiment of the present invention. The rotation of the axial output shaft 114 of the at least one rotary structure 120 rotates the at least one centrifugal disc 302 for circulation, by splashing, of the second coolant within/in the enclosure of the at least one electrical machine 104. The second coolant is radially splashed inside the enclosure of the at least one electrical machine 104. The second coolant is collected/stored/accumulated in at least one sump 304 arranged in the enclosure of the at least one electrical machine 104 for recirculation. The at least one centrifugal disc 302 is partially immersed in the at least one sump 304 for circulation of the second coolant within/in the enclosure of the at least one electrical machine 104 by rotation of the at least one centrifugal disc 302. Upon rotation, the centrifugal disc 302 takes along the second coolant on its surface and splashes it inside the enclosure of the at least one electrical machine 104 due to centrifugal force.

[0017] Fig. 4 illustrates block diagram of the electric drive unit 400 with a pair of rotary structures 420, 430 mechanically coupled to two centrifugal discs 406, 408 respectively, according to an embodiment of the present invention. A pair of a first rotary structure 420 and a second rotary structure 430 is positioned across the at least one electrical machine 104 such that rotation of a first axial output shaft 414 of the first rotary structure 420 rotates a first centrifugal disc 406 and rotation of a second axial output shaft 416 of the second rotary structure 430 rotates a second centrifugal disc 408 for circulation of the second coolant within/in the enclosure of the at least one electrical machine 104 by splashing the second coolant in radial direction. The second coolant is collected/stored/accumulated in a first sump 410 and a second sump 412 arranged in the enclosure of the at least one electrical machine 104 for its recirculation. The first centrifugal disc 406 is partially immersed in the first sump 410 and the second centrifugal disc 408 is partially immersed in the second sump 412 for circulation of the second coolant within/in the enclosure of the at least one electrical machine 104.

[0018] Fig. 5 illustrates block diagram of the electric drive unit 500 with a pair of rotary structure 520, 530 mechanically coupled to two impellers 506, 508 respectively for circulation of the second coolant in the second cooling channel 510, according to an embodiment of the present invention. In an embodiment of the present invention, a pair of a first rotary structure 520 and a second rotary structure 530 is positioned across the at least one electrical machine 104 such that rotation of a first axial output shaft 514 of the first rotary structure 520 rotates a first impeller 506 and rotation of a second axial output shaft 516 of the second rotary structure 530 rotates a second impeller 508 for circulation of the second coolant in the second cooling channel 510 of the at least one electrical machine 104.

[0019] In an embodiment of the present invention, a pair of a first rotary structure 520 and a second rotary structure 530 is positioned across the at least one electrical machine 104 such that rotation of a first axial output shaft 514 of the first rotary structure 520 rotates an impeller 506 and rotation of a second axial output shaft 516 of the second rotary structure 530 rotates a centrifugal disc 408 for circulation of the second coolant within the at least one electrical machine 104. In this embodiment, a combination of the centrifugal disc 408 and the impeller 506 is described as against Fig. 4 and Fig. 5 where combination of the pair of centrifugal discs 406, 408 and the pair of impellers 506, 508 respectively are explained.

[0020] According to the present invention, the electric drive unit 100 of a vehicle with an integrated cooling arrangement is disclosed. The present invention solves the problems discussed above. The present invention solves the cost problem by mechanically coupling the integrated rotary structure 120 with the impeller 202 or the centrifugal disc 302 for circulation of the second coolant for cooling the electrical machine 104 instead of employing an external pump along with its accessories for the same. The present invention also solves the inefficient cooling problem faced during the low-speed operating region of the electrical machine 104 by replacing the dependency on the rotations of the electrical machine 104 with the flow rate of the first coolant in the first cooling channel 108. The flow rate of the first coolant is independent of the speed of the electrical machine 104 as it is circulated by an external pump. Thus, the present invention provides an electric drive unit 100 with active cooling, the cooling function of which is neither expensive nor dependent on the speed of the vehicle.

[0021] 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 (104);
? at least one power electronics unit (102) electronically connected to said at least one electrical machine (104);
? at least one transmission (106) mechanically coupled to said at least one electrical machine (104);
? a first cooling channel (108) arranged around and to cool said at least one power electronics unit (102) with a first coolant;
? a housing enclosing said at least one electrical machine (104), said at least one power electronics unit (102), said at least one transmission (106), and said first cooling channel (108), characterized in that, at least one rotary structure (120), comprising a turbine (112) with an axial output shaft (114), arranged in said housing and in fluid communication with said first cooling channel (108) in such a manner that said turbine (112) with said axial output shaft (114) is rotated by a flow of said first coolant, and rotation of said turbine (112) is translated to a circulation of a second coolant using said axial output shaft (114) for cooling said at least one electrical machine (104).

2. The electric drive unit (100) as claimed in claim 1, wherein said second coolant is circulated in at least one of a second cooling channel (110) of said at least one electrical machine (104) and within an enclosure of said at least one electrical machine (104).

3. The electric drive unit (100) as claimed in claim 1, wherein said axial output shaft (114) of said at least one rotary structure (120) is mechanically coupled with at least one of at least one impeller (202) and at least one centrifugal disc (302) for circulation of said second coolant.

4. The electric drive unit (100) as claimed in claim 3, wherein rotation of said axial output shaft (114) of said at least one rotary structure (120) rotates said impeller (202) for circulation of said second coolant in said second cooling channel (110) of said at least one electrical machine (104).

5. The electric drive unit (100) as claimed in claim 3, wherein rotation of said axial output shaft (114) of said at least one rotary structure (120) rotates said at least one centrifugal disc (302) for circulation, by splashing, of said second coolant within said enclosure of said at least one electrical machine (104) by splashing said second coolant radially.

6. The electric drive unit (100) as claimed in claim 3, wherein a pair of a first rotary structure (420) and a second rotary structure (430) is positioned across said at least one electrical machine (104) such that rotation of a first axial output shaft (414) of said first rotary structure (420) rotates a first centrifugal disc (406) and rotation of a second axial output shaft (416) of said second rotary structure (430) rotates a second centrifugal disc (408) for circulation of said second coolant within said enclosure of said at least one electrical machine (104).

7. The electric drive unit (100) as claimed in claim 3, wherein a pair of a first rotary structure (520) and a second rotary structure (530) is positioned across said at least one electrical machine (104) such that rotation of a first axial output shaft (514) of said first rotary structure (520) rotates a first impeller (506) and rotation of a second axial output shaft (516) of said second rotary structure (530) rotates a second impeller (508) for circulation of said second coolant in said second cooling channel (510) of said at least one electrical machine (104).

8. The electric drive unit (100) as claimed in claim 3, wherein a pair of a first rotary structure (520) and a second rotary structure (530) is positioned across said at least one electrical machine (104) such that rotation of a first axial output shaft (514) of said first rotary structure (520) rotates an impeller (506) and rotation of a second axial output shaft (516) of said second rotary structure (530) rotates a centrifugal disc (408) for circulation of said second coolant within said at least one electrical machine (104).

9. The electric drive unit (100) as claimed in claim 5, wherein said second coolant is collected in at least one sump (304) arranged in said enclosure of said at least one electrical machine (104) for recirculation.

10. The electric drive unit (100) as claimed in claim 9, wherein said at least one centrifugal disc (302, 406, 408) is partially immersed in said at least one sump (304, 410, 412) for circulation of said second coolant within said enclosure of said at least one electrical machine (104) by rotation of said at least one centrifugal disc (302, 406, 408).