DE102023211158A1 - Drivetrain - Google Patents

Abstract

The invention relates to a drive train (1), in particular for a hybrid vehicle or for an electric vehicle, with at least one transmission (2), with at least one power electronics unit (3) and with a housing (4), wherein a transmission chamber (5) and a power electronics chamber (6) are formed in the housing (4), wherein the transmission (2) is arranged at least partially in the transmission chamber (5) and the power electronics unit (3) is arranged at least partially in the power electronics chamber (6), and wherein the transmission chamber (5) and the power electronics chamber (6) are separated from one another by means of a partition wall (7) of the housing (4).
The installation space required for the drive train (1) is minimized and the transmission (2) and the power electronics (3) can be cooled more easily, in particular with less design effort and more effectively, in that the partition wall (7) has a first cooling channel (8.1) and a second cooling channel (8.2), wherein both the transmission (2) and the power electronics (3) can each be at least partially cooled by means of a cooling fluid (9) flowing through the first and/or second cooling channel (8.1, 8.2), wherein a power electronics cooler (10) is provided and/or present, wherein the cooling fluid (9) can be fed from the first cooling channel (8.1) to the power electronics cooler (10) and wherein the cooling fluid (9) can be discharged from the power electronics cooler (10) via the second cooling channel (8.2).

Description

The invention relates to a drive train with the features of the preamble of patent claim 1.

Drivetrains for hybrid vehicles or for electric vehicles comprising a transmission, power electronics, and a housing are known in the art. The power electronics convert the electrical energy that can be supplied to or discharged from an electric motor of the electric vehicle, e.g., to enable coupling of the electric motor to a battery. A transmission compartment and a power electronics compartment are formed in the housing. The transmission is at least partially arranged in the transmission compartment, and the power electronics are at least partially arranged in the power electronics compartment. The transmission compartment and the power electronics compartment are separated from one another by a partition wall of the housing. Transmission oil is typically present in the transmission for cooling and/or lubricating at least parts of the transmission. The transmission oil typically collects in a transmission sump and, during transmission operation, is propelled upwards by a gearwheel of the transmission arranged in a splashing motion in the transmission sump, particularly toward the transmission elements to be cooled and/or lubricated. The partition wall separates the power electronics compartment from the transmission compartment and, if necessary, seals it accordingly, preventing transmission oil from penetrating the power electronics compartment. This protects the power electronics from contact with the transmission oil, ensuring proper function.

In the US 7 156 195 B2 is shown a drive train for an electric vehicle with an electric motor, with a transmission and with a housing. A transmission chamber and an electric motor chamber are formed in the housing. The transmission is arranged in the transmission chamber and the electric motor is arranged in the electric motor chamber. The transmission chamber and the electric motor chamber are separated from one another by a partition wall in the housing. A cooling fluid in the form of cooling oil can be pumped from a transmission sump by means of a pump through a cooler and a cooling channel formed in a shaft of the transmission. From the cooling channel in the shaft of the transmission, the cooling fluid can be pumped via the transmission back into its transmission sump. From the cooling channel in the shaft of the transmission, the cooling fluid can be pumped via cooling channels in a shaft of the electric motor, via a chamber for a rotary encoder and via a channel arranged outside the housing back into the transmission sump.

However, with this type of cooling channel layout, the power electronics of the electric motor cannot be cooled, or only with considerable additional effort. Furthermore, a large amount of space is required for the cooling fluid channels and the housing as a whole.

From the DE 10 2019 209 907 A1 Another drive train for a hybrid vehicle is known, comprising an internal combustion engine, an electric motor, power electronics, in particular an inverter, and a temperature control circuit. The temperature control circuit has a main pumping device for a temperature control fluid, a main section with a cooler, a first parallel section with the internal combustion engine, and a second parallel section with electric drive components such as the electric motor and/or the power electronics, and an auxiliary pumping device. The temperature control circuit is at least partially formed with the aid of corresponding temperature control channels. If the temperature control circuit is used for cooling, it can also be referred to as a cooling circuit, so that one can then speak of a cooling fluid and cooling channels accordingly.

Here, too, a large installation space must be provided for the drive train, in particular for the channels of the temperature control circuit including the temperature control channels.

The invention is therefore based on the object of designing and/or developing the drive train in such a way that the problems of the prior art are avoided or at least reduced, in particular the installation space required for the drive train is minimized, wherein the transmission and the power electronics can be cooled more simply, in particular with less design effort and/or more effectively.

This problem underlying the invention is now initially solved by a drive train having the features of patent claim 1.

One aspect of the invention is essentially that the partition wall has a first cooling channel and a second cooling channel, wherein both the transmission and the power electronics can each be at least partially cooled by means of a cooling fluid flowing through the first and/or second cooling channel, wherein a power electronics cooler is provided and/or present, wherein the cooling fluid can be fed from the first cooling channel to the power electronics cooler and wherein the cooling fluid can be discharged from the power electronics cooler via the second cooling channel.

Thus, the first cooling channel, the power electronics cooler and the second cooling channel connected in series for fluidic purposes. Preferably, the power electronics are at least partially in contact with the partition wall, in particular forming a thermally conductive connection. Thus, the power electronics can be cooled particularly well with the aid of the cooling fluid present in the first and/or second cooling channel. Furthermore, with such an arrangement of the first and/or second cooling channel, the power electronics cooler, and the housing, only a small installation space is required overall. Cooling the transmission and the power electronics is particularly simple and can be carried out with little effort in terms of device technology as well as control and/or regulation technology.

Preferably, the first cooling channel and the second cooling channel are arranged and/or configured to extend substantially spatially parallel to one another. Thus, the distance between the two cooling channels can be made particularly small, so that the transmission and the power electronics can be cooled evenly over a large area by means of the cooling fluid present in the two cooling channels. Furthermore, the two cooling channels are thus space-saving and can be configured in a small installation space. The two cooling channels are preferably aligned substantially horizontally. The partition wall is preferably aligned substantially vertically.

Further preferably, the first cooling channel and the second cooling channel each have an inlet opening and an outlet opening. The inlet opening of the first cooling channel and the inlet opening of the second cooling channel are arranged adjacently in associated first end regions of the respective cooling channels. The outlet opening of the first cooling channel and the outlet opening of the second cooling channel are arranged adjacently in associated second end regions of the respective cooling channels. Thus, from a spatial perspective, the cooling fluid can flow through the first cooling channel in the same direction as the second cooling channel. The end regions of the respective cooling channels are preferably arranged in opposite edge regions of the housing, such that the partition can be cooled over a large part of its width. Furthermore, a simple connection of the cooling channels to external pipes, hoses or the like is then conceivable.

In a further embodiment of the drive train, the drive train has an electric motor. A cooling region of the electric motor is connected to the second cooling channel, in particular the outlet opening of the second cooling channel. The electric motor is an electrical machine that can be operated as a motor or as a generator. The electric motor has a rotor and a stator, wherein the cooling region is designed to cool the rotor and/or the stator. It is conceivable that the electric motor is also arranged in the housing, in particular in an electric motor compartment of the housing. Furthermore, a separate housing could be provided and/or present for the electric motor.

In a further preferred embodiment of the drive train, the power electronics, in particular an intermediate circuit capacitor of the power electronics, is spatially arranged between the power electronics cooler and the first and/or second cooling channel. Thus, the power electronics, in particular the intermediate circuit capacitor, can be cooled particularly effectively, namely from two opposite sides. In particular, the power electronics cooler is thus arranged at a distance from the partition wall.

Particularly effective cooling of the transmission can be achieved if a cooling surface of the partition wall, which defines the transmission chamber and is arranged adjacent to the first and/or second cooling channel, has ribs for cooling the transmission oil present in the transmission chamber. These ribs improve the heat transfer between the transmission oil and the cooling fluid, as the ribs increase the surface area for heat transfer between the partition wall and the transmission oil. Furthermore, the cooling fluid remains on the cooling surface longer during driveline operation due to the ribs, thus extending the time for heat transfer.

Preferably, the first cooling channel is fluidically connected to the power electronics cooler via a supply channel. The second cooling channel is fluidically connected to the power electronics cooler via a return channel. Preferably, the supply channel and/or the return channel are arranged at least partially adjacent to the power electronics, in particular the intermediate circuit capacitor of the power electronics, so that the power electronics can then also be cooled by the cooling fluid present in the supply channel and/or the return channel.

Advantageously, the supply channel and the return channel are arranged and/or configured to extend substantially spatially parallel to one another. The supply channel and/or the return channel are preferably arranged and/or aligned substantially perpendicular to the cooling channels.

According to a particularly preferred embodiment of the drive train, the feed channel and the return channel are on opposite sides of at least parts of the Power electronics, in particular the intermediate circuit capacitor of the power electronics, are arranged and/or formed. Thus, the power electronics, in particular the intermediate circuit capacitor, can be cooled even more effectively, namely from two additional opposite sides. Overall, a flow around the power electronics, in particular the intermediate circuit capacitor, along a square helix by means of the first cooling channel, the supply channel, the power electronics cooler, the return channel, and the second cooling channel is particularly conceivable. Such a course of a square helix can be interrupted by a correspondingly more complex flow through the power electronics cooler.

Further preferably, the first cooling channel and/or the second cooling channel and/or the power electronics cooler and/or the supply channel and/or the return channel are formed as recesses in the housing. The recesses can be created, for example, using casting cores if the housing is manufactured using a casting process. Furthermore, it is conceivable for recesses to be introduced into the joining surfaces of housing parts, and for the corresponding channels to then be created when the housing parts are assembled to form the housing.

The first cooling channel, the second cooling channel, the power electronics cooler, in particular the supply channel, in particular the return channel, and in particular the cooling area of the electric motor are preferably part of a cooling circuit through which the cooling fluid can be pumped by means of a pump. Such a cooling circuit can have additional elements such as an expansion tank.

• 1 in schematischer Darstellung ein erstes Ausführungsbeispiel des Antriebsstranges in einer dreidimensionalen Ansicht im Schnitt durch einen ersten Kühlkanal,
• 2 in schematischer Darstellung den Antriebsstrang aus 1 in einer Seitenansicht im Schnitt durch den ersten und einen zweiten Kühlkanal,
• 3 in schematischer Darstellung den Antriebsstrang aus 1 in einer Draufsicht im Schnitt durch den zweiten Kühlkanal,
• 4 in schematischer Darstellung ein Systemschaubild eines zweiten Ausführungsbeispiels des Antriebsstranges mit Strömungsverläufen eines Kühlfluids, und
• 5 in schematischer Darstellung einen Flusslaufplan des Kühlfluids im Antriebsstrang gemäß seines ersten oder zweiten Ausführungsbeispiels.

There are now numerous possibilities for advantageously designing and developing the drive train according to the invention. Reference is first made to the claims subordinate to claim 1. A preferred embodiment of the drive train according to the invention will now be explained and described in more detail with reference to the drawing and the associated description. The drawing shows:

• 1 in schematic representation a first embodiment of the drive train in a three-dimensional view in section through a first cooling channel,
• 2 schematic representation of the drive train 1 in a side view in section through the first and a second cooling channel,
• 3 schematic representation of the drive train 1 in a plan view in section through the second cooling channel,
• 4 in schematic representation a system diagram of a second embodiment of the drive train with flow patterns of a cooling fluid, and
• 5 in schematic representation a flow diagram of the cooling fluid in the drive train according to its first or second embodiment.

1 until 3 each show a drive train 1, in particular for a hybrid vehicle or for an electric vehicle, with at least one transmission 2, with at least one power electronics unit 3 and with a housing 4 in various views. A transmission chamber 5 and a power electronics chamber 6 are formed in the housing 4. The transmission 2 is at least partially arranged in the transmission chamber 5. The power electronics unit 3 is at least partially arranged in the power electronics chamber 6. The transmission chamber 5 and the power electronics chamber 6 are separated from one another by means of a partition wall 7 of the housing 4.

The gear compartment 5 and the power electronics compartment 6 are formed in the housing 4 essentially horizontally next to each other, as can be seen in particular in the plan view from 3 The gear 2 has at least two gear wheels for forming at least one gear stage of the gear 2. The gear 2 is in 1 and 2 only partially shown, namely corresponding bearings of the gearbox 2, wherein associated shafts and gears arranged and/or formed thereon are omitted.

The partition wall 7 has a first cooling channel 8.1 and a second cooling channel 8.2. By means of a cooling fluid 9 flowing through the first and/or second cooling channel 8.1, 8.2, both the transmission 2 and the power electronics 3 can each be at least partially cooled. A power electronics cooler 10 is provided and/or present. The cooling fluid 9 can be fed from the first cooling channel 8.1 to the power electronics cooler 10. The cooling fluid 9 can be discharged from the power electronics cooler 10 via the second cooling channel 8.2. The flow path of the cooling fluid 9 is symbolized by arrows, with the entire flow path being shown in particular in 4 and 5 In contrast to the first embodiment, the two cooling channels 8.1, 8.2 in the second embodiment are made of 4 vertically swapped. According to 1 until 3 the second cooling channel 8.2 is located above the first cooling channel 8.1. According to 4 the first cooling channel 8.1 is located above the second cooling channel 8.2. During operation of the drive train 1, heat is transferred from the transmission 2 and the power electronics 3 to the cooling fluid 9 as the cooling fluid flows through the cooling channels 8.1, 8.2 and the power electronics cooler 10. The cooling fluid 9 is then discharged from the drive train 1 at an elevated temperature. Preferably, the cooling fluid 9 is circulated and, after cooling, is returned to the drive train 1, in particular to the first cooling channel 8.1.

The first cooling channel 8.1 and the second cooling channel 8.2 are arranged and/or formed to run essentially spatially parallel to one another. The first cooling channel 8.1 and/or the second cooling channel 8.2 are aligned essentially horizontally. Alternatively, an inclined or even vertical alignment would also be conceivable. Preferably, a vertical plane penetrates the first cooling channel 8.1 and the second cooling channel 8.2. The partition wall 7 is correspondingly arranged essentially vertically. The partition wall could also be aligned inclined or even horizontally. The partition wall could also have a more complex shape with various inclined, vertical and/or horizontal regions. The partition wall 7 is formed by a narrow, inner region of the housing 4, which delimits the gear chamber 5 on one side and the power electronics chamber 6 on the opposite side. In the area of the cooling channels 8.1, 8.2, the partition wall 7 as a whole, including the cooling channels 8.1, 8.2, is thicker than next to the cooling channels 8.1, 8.2, whereby the thicknesses can be measured along the shortest connecting lines between the gear compartment 5 and the power electronics compartment 6 through the partition wall 7.

The first cooling channel 8.1 and the second cooling channel 8.2 each have an inlet opening 8.1.E, 8.2.E and an outlet opening 8.1.A, 8.2.A. The inlet opening 8.1.E of the first cooling channel 8.1 and the inlet opening 8.2.E of the second cooling channel 8.2 are arranged adjacently in associated first end regions 11.1 of the respective cooling channels 8.1, 8.2. The outlet opening 8.1.A of the first cooling channel 8.1 and the outlet opening 8.2.A of the second cooling channel 8.2 are arranged adjacently in associated second end regions 11.2 of the respective cooling channels 8.1, 8.2. The two end regions 11.1, 11.2 are each arranged adjacent to an outer wall of the housing 4. The two end regions 11.1, 11.2 are arranged on opposite sides of the housing 4. The partition wall 7 can thus be flowed through by the cooling fluid 9 essentially completely along its width in the horizontal direction.

The drive train 1 has a 5 symbolically represented electric motor 12. A cooling region 13 of the electric motor 12 is connected to the second cooling channel 8.2, in particular the outlet opening 8.2.A of the second cooling channel 8.2. The electric motor 12 is arranged either in the housing 4 or in a separate housing. The electric motor 12 has a rotor and a stator. In principle, various types of electric motors are conceivable. Preferably, the electric motor 12 is operated with an alternating current in motor mode, or the electric motor supplies such an alternating current in generator mode. This alternating current can be converted into a direct current by means of the power electronics 3 for exchange with a battery of the hybrid vehicle or the electric vehicle.

The power electronics 3 are at least partially spatially arranged between the power electronics cooler 10 and the first and/or second cooling channel 8.1, 8.2. In particular, an intermediate circuit capacitor 14 of the power electronics 3 is spatially arranged between the power electronics cooler 10 and the first and/or second cooling channel 8.1, 8.2. The power electronics 3, in particular the intermediate circuit capacitor 14, heats up considerably during operation and therefore requires significant cooling. This is made possible in particular by the cooling on both sides. The intermediate circuit capacitor 14 enables the energetic coupling of several electrical networks to one another at a common DC voltage level.

A cooling surface 15 of the partition wall 7, which defines the transmission chamber 5 and is arranged adjacent to the first and/or second cooling channels 8.1, 8.2, has ribs 16 for cooling transmission oil present in the transmission chamber 5. The ribs 16 extend in a substantially horizontal direction from the partition wall 7 into the transmission chamber 5. The ribs 16 run parallel to one another. The ribs 16 are at an angle to a vertical plane running perpendicular to the partition wall 7. Other arrangements and/or configurations of the ribs are conceivable.

The first cooling channel 8.1 is fluidly connected to the power electronics cooler 10 via a supply channel 17. The second cooling channel 8.2 is fluidly connected to the power electronics cooler 10 via a return channel 18. The cooling fluid 9 can be fed to the supply channel 17 via the outlet opening 8.1.A of the first cooling channel 8.1 and to the power electronics cooler 10 via an outlet opening of the supply channel 17 via its inlet. The cooling fluid 9 can also be discharged from the power electronics cooler 10 via an outlet of the power electronics cooler 10 and fed to the return channel 18. Via an outlet opening of the return channel 18, the cooling fluid 9 can be fed to the second cooling channel 8.2 via its inlet opening 8.2.E.

The supply channel 17 and the return channel 18 are arranged and/or configured to extend substantially spatially parallel to one another. The supply channel 17 and the return channel 18 are arranged and/or configured substantially horizontally, possibly slightly inclined to a horizontal plane.

The supply channel 17 and the return channel 18 are arranged and/or formed on opposite sides of at least parts of the power electronics 3, in particular the intermediate circuit capacitor 14 of the power electronics 3. Thus, parts of the power electronics 3, in particular the intermediate circuit capacitor 14, can be flowed around on four, in particular vertically aligned sides. The two cooling channels 8.1, 8.2 are arranged adjacent to a first side. The supply channel 17 is arranged adjacent to a second side. The power electronics cooler 10 is arranged adjacent to a third side. The return channel 18 is arranged adjacent to a fourth side.

The first cooling channel 8.1 and/or the second cooling channel 8.2 and/or the power electronics cooler 10 and/or the supply channel 17 and/or the return channel 18 are formed as recesses in the housing 4. Alternatively, the channels 8.1, 8.2, 17, 18 can be formed using pipes and/or hoses. However, the drive train 1 can be designed in a particularly space-saving manner, in particular with the channels 8.1, 8.2, 17, 18 formed as recesses in the housing 4.

Preferably, at least one insert is arranged in a recess of the housing 4 provided for forming the power electronics cooler 10. The insert then enables a complex, e.g., meandering flow through the power electronics cooler 10. This can improve the heat transfer to the cooling fluid 9 present in the power electronics cooler 10. Such an insert then has corresponding walls and/or webs for forming flow channels within the power electronics cooler 10.

List of reference symbols

1

Drivetrain

2

Gearbox

3

Power electronics

4

Housing

5

Gearbox compartment

6

Power electronics room

7

partition

8.1

first cooling channel

8.1.E

Inlet opening of the first cooling channel 8.1

8.1.A

Outlet of the first cooling channel 8.1

8.2

second cooling channel

8.2.E

Inlet opening of the second cooling channel 8.2

8.2.A

Outlet of the second cooling channel 8.2

9

Cooling fluid

10

Power electronics cooler

11.1

first end areas of the respective cooling channels 8.1, 8.2

11.2

second end areas of the respective cooling channels 8.1, 8.2

12

electric motor

13

Cooling area of the electric motor 12

14

DC link capacitor of the power electronics 3

15

Cooling surface of the partition wall 7

16

ribs

17

flow channel

18

Return channel

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7 156 195 B2 [0003]
• DE 10 2019 209 907 A1 [0005]

Claims (10)

Drive train (1), in particular for a hybrid vehicle or for an electric vehicle, with at least one transmission (2), with at least one power electronics unit (3), and with a housing (4), wherein a transmission chamber (5) and a power electronics chamber (6) are formed in the housing (4), wherein the transmission (2) is arranged at least partially in the transmission chamber (5) and the power electronics unit (3) is arranged at least partially in the power electronics chamber (6), and wherein the transmission chamber (5) and the power electronics chamber (6) are separated from one another by means of a partition wall (7) of the housing (4), characterized in that the partition wall (7) has a first cooling channel (8.1) and a second cooling channel (8.2), wherein both the transmission (2) and the power electronics unit (3) can each be at least partially cooled by means of a cooling fluid (9) flowing through the first and/or second cooling channel (8.1, 8.2), wherein a power electronics cooler (10) is provided and/or present, wherein the cooling fluid (9) can be fed from the first cooling channel (8.1) to the power electronics cooler (10) and wherein the cooling fluid (9) can be discharged from the power electronics cooler (10) via the second cooling channel (8.2). Drivetrain (1) to Claim 1 , characterized in that the first cooling channel (8.1) and the second cooling channel (8.2) are arranged and/or formed to run substantially spatially parallel to one another. Drive train (1) according to one of the preceding claims, characterized in that the first cooling channel (8.1) and the second cooling channel (8.2) each have an inlet opening (8.1.E, 8.2.E) and an outlet opening (8.1.A, 8.2.A), wherein the inlet opening (8.1.E) of the first cooling channel (8.1) and the inlet opening (8.2.E) of the second cooling channel (8.2) are arranged adjacently in associated first end regions (11.1) of the respective cooling channels (8.1, 8.2), wherein the outlet opening (8.1.A) of the first cooling channel (8.1) and the outlet opening (8.2.A) of the second cooling channel (8.2) are arranged adjacently in associated second end regions (11.2) of the respective cooling channels (8.1, 8.2). Drive train (1) according to one of the preceding claims, characterized in that the drive train (1) has an electric machine (12), wherein a cooling region (13) of the electric machine (12) is connected to the second cooling channel (8.2), in particular the outlet opening (8.2.A) of the second cooling channel (8.2). Drive train (1) according to one of the preceding claims, characterized in that the power electronics (3), in particular an intermediate circuit capacitor (14) of the power electronics (3), is arranged spatially between the power electronics cooler (10) and the first and/or second cooling channel (8.1, 8.2). Drive train (1) according to one of the preceding claims, characterized in that a cooling surface (15) of the partition wall (7) delimiting the transmission chamber (5) and arranged adjacent to the first and/or second cooling channel (8.1, 8.2) has ribs (16) for cooling transmission oil present in the transmission chamber (5). Drive train (1) according to one of the preceding claims, characterized in that the first cooling channel (8.1) is fluidically connected to the power electronics cooler (10) by means of a supply channel (17), wherein the second cooling channel (8.2) is fluidically connected to the power electronics cooler (10) by means of a return channel (18). Drivetrain (1) to Claim 7 , characterized in that the feed channel (17) and the return channel (18) are arranged and/or formed to run substantially spatially parallel to one another. Drivetrain (1) to Claim 7 or 8 , characterized in that the feed channel (17) and the return channel (18) are arranged and/or formed on opposite sides of at least parts of the power electronics (3), in particular the intermediate circuit capacitor (14) of the power electronics (3). Drive train (1) according to one of the preceding claims, characterized in that the first cooling channel (8.1) and/or the second cooling channel (8.2) and/or the power electronics cooler (10) and/or the supply channel (17) and/or the return channel (18) are designed as recesses in the housing (4).

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