Multi-motor drive assembly cooling system and vehicle

Abstract

The utility model provides a multi-motor drive assembly cooling system and a vehicle. The multi-motor drive assembly cooling system comprises a water cooling loop and an oil cooling loop. The oil cooling loop comprises a cooling oil way arranged on the speed reducer; the water cooling loop comprises a water tank with a water outlet and a water return port; the at least two controller cooling water paths are arranged on the at least two controllers in a one-to-one correspondence manner; the at least two motor cooling water paths are arranged on the at least two driving motors in a one-to-one correspondence manner; the speed reducer cooling water path is arranged on the speed reducer and can be used for cooling the cooling oil path; the water cooling loop is divided into at least two water cooling branches which are arranged in parallel, each water cooling branch comprises a water tank water outlet, at least one controller cooling water channel, at least one motor cooling water channel and a water tank water return port which are communicated in sequence, and a water pump is arranged on each water cooling branch; and the motor cooling water path of at least one water cooling branch is communicated with the water return port of the water tank through a speed reducer cooling water path. And the cooling effect on the speed reducer can be improved.

Description

Technical Field

[0001] This application relates to the field of cooling and lubrication technology for electric drive systems, specifically to a multi-motor drive assembly cooling system, and also to a vehicle including the aforementioned multi-motor drive assembly cooling system. Background Technology

[0002] In multi-motor reducers, especially those with multiple high-speed motors, the gears are constantly operating at high speeds, causing a rapid increase in the reducer's operating temperature, necessitating cooling. Reducers typically employ splash lubrication and active lubrication to lubricate and cool moving parts such as gears and bearings.

[0003] Currently, there are two main cooling methods for gearbox lubricating oil. One method relies on the heat dissipation of the gearbox housing for cooling, which has a poor cooling effect. In high-speed gearboxes, insufficient heat dissipation can lead to increased oil temperature, causing damage to gears and bearings. The other method uses an external circulating cooling device (including an oil pump, oil pipes, and an oil cooler) to draw lubricating oil from the gearbox into the oil cooler for heat exchange and cooling, before returning the cooled lubricating oil to the gearbox. Although this method improves the cooling effect, the addition of an external circulating cooling device results in more cooling components, increasing space requirements and investment costs. It is also difficult to implement in space-constrained environments, and the external circulating cooling device increases the risk of oil leakage. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a multi-motor drive assembly cooling system to improve the cooling effect of the reducer, while reducing the space occupied and investment cost.

[0005] The purpose of this application is also to provide a vehicle including the above-mentioned multi-motor drive assembly cooling system to improve the cooling effect of the reducer, while reducing the space occupied and investment costs.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A cooling system for a multi-motor drive assembly includes a water-cooling circuit and an oil-cooling circuit; wherein the oil-cooling circuit includes a cooling oil passage disposed on the reducer of the multi-motor drive assembly.

[0008] The water-cooling circuit includes:

[0009] A water tank that stores cooling water and has an outlet and a return outlet;

[0010] At least two controller cooling water circuits are provided on at least two controllers of the multi-motor drive assembly in a one-to-one correspondence;

[0011] At least two motor cooling water circuits are provided one-to-one on at least two drive motors of the multi-motor drive assembly;

[0012] The reducer cooling water circuit is installed on the reducer and can cool the cooling oil circuit.

[0013] The water cooling circuit is divided into at least two water cooling branches connected in parallel. Each water cooling branch includes the outlet of the water tank, at least one controller cooling water circuit, at least one motor cooling water circuit and the return water outlet of the water tank connected in sequence. Each water cooling branch is equipped with a water pump to promote water circulation.

[0014] At least one of the motor cooling water circuits and the return water inlet of the water tank are connected through the reducer cooling water circuit.

[0015] Preferably, in the above-mentioned multi-motor drive assembly cooling system, at least one of the reducer cooling water circuit and the cooling oil circuit is provided with a heat exchange groove recessed towards the other.

[0016] Preferably, in the above-mentioned multi-motor drive assembly cooling system, a first heat exchange groove recessed towards the coolant cooling water passage of the reducer is provided on the cooling oil circuit;

[0017] The reducer cooling water line is provided with a second heat exchange groove that is recessed towards the cooling oil line.

[0018] Preferably, in the above-mentioned multi-motor drive assembly cooling system, there are multiple first heat exchange slots and multiple second heat exchange slots, which are staggered along the axial direction of the reducer.

[0019] Preferably, in the above-mentioned multi-motor drive assembly cooling system, the projections of the first heat exchange slot and the second heat exchange slot along the axial direction of the reducer partially overlap.

[0020] Preferably, in the above-mentioned multi-motor drive assembly cooling system, the cooling oil circuit includes an oil pan, which has an oil cavity for collecting and storing lubricating oil;

[0021] The coolant channels for the reducer are located on the oil pan.

[0022] Preferably, in the above-mentioned multi-motor drive assembly cooling system, in each of the water-cooled branches, the outlet of the water tank is connected to at least one of the controller cooling water circuits via an outlet pipe. A flow control valve is provided on the outlet pipe. The flow control valve is used to connect to the vehicle control unit. The vehicle control unit can control the opening degree of the flow control valve according to the corresponding loop resistance in each of the water-cooled branches and / or the output power of all drive motors.

[0023] Preferably, in the above-mentioned multi-motor drive assembly cooling system, the at least two water-cooling branches include a first water-cooling branch and a second water-cooling branch;

[0024] Wherein, at least one outlet of the motor cooling water circuit of the first water-cooling branch and the return outlet of the water tank are connected by a first return water pipe.

[0025] At least one outlet of the motor cooling water circuit of the second water-cooled branch is connected to the inlet of the reducer cooling water circuit, and the outlet of the reducer cooling water circuit and the return outlet of the water tank are connected by a second return water pipe.

[0026] Preferably, in the above-mentioned multi-motor drive assembly cooling system, each of the water-cooled branches includes one controller cooling water circuit and two motor cooling water circuits.

[0027] As can be seen from the above technical solution, the multi-motor drive assembly cooling system provided in this application includes a water-cooled circuit and an oil-cooled circuit; wherein, the oil-cooled circuit includes a cooling oil circuit disposed on the reducer of the multi-motor drive assembly; the water-cooled circuit includes: a water tank storing cooling water, having an outlet and a return outlet; at least two controller cooling water circuits, disposed one-to-one on at least two controllers of the multi-motor drive assembly; at least two motor cooling water circuits, disposed one-to-one on at least two drive motors of the multi-motor drive assembly; a reducer cooling water circuit disposed on the reducer, and capable of cooling the cooling oil circuit; wherein, the water-cooled circuit is divided into at least two water-cooled branches disposed in parallel, each water-cooled branch including the outlet of the water tank, at least one controller cooling water circuit, at least one motor cooling water circuit and the return outlet of the water tank connected in sequence, and each water-cooled branch is provided with a water pump to promote water circulation; at least one motor cooling water circuit of at least one water-cooled branch and the return outlet of the water tank are connected through the reducer cooling water circuit.

[0028] When the multi-motor drive assembly cooling system provided in this application is applied, on the one hand, the oil in the oil cooling circuit circulates in the reducer of the multi-motor drive assembly to cool and reduce the temperature of the reducer.

[0029] On the other hand, the cooling water in the water-cooling circuit circulates in parallel in at least two water-cooling branches. In each water-cooling branch, driven by a water pump, the cooling water in the water tank is output from the outlet and flows sequentially through at least one controller cooling water circuit and at least one motor cooling water circuit, and then flows back into the water tank through the return port. The cooling water circulating in the water-cooling branch cools down at least two controllers and at least two drive motors of the multi-motor drive assembly. At the same time, in at least one water-cooling branch, the cooling water flowing out from at least one motor cooling water circuit flows through the reducer cooling water circuit and then flows back into the water tank through the return port. During this process, the cooling water flowing in the reducer cooling water circuit exchanges heat with the oil in the cooling oil circuit on the reducer, thereby cooling down the cooling oil circuit on the reducer and cooling down the oil circulating in the oil-cooling circuit.

[0030] Therefore, the multi-motor drive assembly cooling system provided in this application sets at least two parallel water-cooling branches between at least two controllers, at least two drive motors, and the reducer of the multi-motor drive assembly to form a water-cooling circuit; sets an oil-cooling circuit in the reducer of the multi-motor drive assembly; and cools down the oil-cooling circuit on the reducer through at least one water-cooling branch of the water-cooling circuit, thereby achieving oil-water composite cooling of the reducer. Compared with relying on the reducer housing for heat dissipation, it can improve the cooling effect of the reducer; at the same time, it does not require the addition of an external circulating cooling device, reducing the space occupied and investment cost, facilitating the layout under space constraints, and avoiding the risk of oil leakage.

[0031] This application also provides a vehicle including a multi-motor drive assembly and a cooling system for cooling the multi-motor drive assembly. The cooling system is any of the multi-motor drive assembly cooling systems described above. Since the multi-motor drive assembly cooling systems described above have the above-mentioned effects, the vehicle having the multi-motor drive assembly cooling system has the same effects, so it will not be described again here. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 A schematic diagram of the flow paths of the water-cooling circuit and the oil-cooling circuit of the multi-motor drive assembly cooling system provided in the embodiments of this application;

[0034] Figure 2 This is a schematic diagram of the structure of the multi-motor drive assembly cooling system provided in the embodiments of this application;

[0035] Figure 3 This is a schematic diagram of the reducer of the multi-motor drive assembly provided in an embodiment of this application.

[0036] superior Figure 1-3 middle:

[0037] 1-Controller, 2-Drive motor, 3-Reducer, 31-Reducer cooling water circuit, 32-Oil pan, 33-Second heat exchange tank, 34-First heat exchange tank, 4-First water cooling pipe, 5-Second return water pipe, 6-Second water cooling pipe. Detailed Implementation

[0038] This application provides a multi-motor drive assembly cooling system and a vehicle including the above-mentioned multi-motor drive assembly cooling system, which can improve the cooling effect of the reducer while reducing the space occupied and investment costs.

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] like Figures 1-3 As shown, the multi-motor drive assembly cooling system provided in this application embodiment includes a water-cooled circuit and an oil-cooled circuit; wherein, the oil-cooled circuit includes a cooling oil passage disposed on the reducer 3 of the multi-motor drive assembly; the water-cooled circuit includes: a water tank storing cooling water, having an outlet and a return outlet; at least two controller cooling water passages, each correspondingly disposed on at least two controllers 1 of the multi-motor drive assembly; at least two motor cooling water passages, each correspondingly disposed on at least two drive motors 2 of the multi-motor drive assembly; a reducer cooling water passage 31, disposed on the reducer 3, and capable of cooling the cooling oil passage; wherein, the water-cooled circuit is divided into at least two water-cooled branches disposed in parallel, each water-cooled branch including the outlet of the water tank, at least one controller cooling water passage, at least one motor cooling water passage, and the return outlet of the water tank connected in sequence, and each water-cooled branch is provided with a water pump to promote water circulation; at least one motor cooling water passage of at least one water-cooled branch and the return outlet of the water tank are connected through the reducer cooling water passage 31.

[0041] When the multi-motor drive assembly cooling system provided in this embodiment is applied, on the one hand, the oil in the oil cooling circuit circulates in the reducer 3 of the multi-motor drive assembly to cool and reduce the temperature of the reducer 3.

[0042] On the other hand, the cooling water in the water-cooling circuit circulates in parallel in at least two water-cooling branches. In each water-cooling branch, driven by a water pump, the cooling water in the water tank is output from the outlet and flows sequentially through at least one controller cooling water circuit and at least one motor cooling water circuit, and then flows back into the water tank through the return port. The cooling water circulating in the water-cooling branch cools down at least two controllers 1 and at least two drive motors 2 of the multi-motor drive assembly. At the same time, in at least one water-cooling branch, the cooling water flowing out from at least one motor cooling water circuit flows through the reducer cooling water circuit 31 and then flows back into the water tank through the return port. During this process, the cooling water flowing in the reducer cooling water circuit 31 exchanges heat with the oil in the cooling oil circuit on the reducer 3, thereby cooling down the cooling oil circuit on the reducer 3 and cooling down the oil circulating in the oil-cooling circuit.

[0043] Therefore, the multi-motor drive assembly cooling system provided in this application sets at least two parallel water-cooling branches between at least two controllers 1, at least two drive motors 2, and reducer 3 of the multi-motor drive assembly to form a water-cooling circuit; sets an oil-cooling circuit in the reducer 3 of the multi-motor drive assembly; and cools down the oil-cooling circuit on the reducer 3 through at least one water-cooling branch of the water-cooling circuit, thereby realizing oil-water composite cooling of the reducer 3. Compared with relying on the heat dissipation of the reducer 3 housing, it can improve the cooling effect of the reducer 3; at the same time, there is no need to add an external circulating cooling device, which reduces the space occupied and investment cost, facilitates the layout under space constraints, and avoids the risk of oil leakage.

[0044] It should be noted that the multi-motor drive assembly cooling system provided in this application is adapted for cooling multi-motor drive assemblies. The multi-motor drive assembly includes multiple drive motors 2 and reducers 3 connected to the drive motors 2. A controller 1 is connected to each drive motor 2. The multi-motor drive assembly can meet different power requirements, resulting in higher overall output power and cost savings. Using the multi-motor drive assembly cooling system provided in this application allows for a more compact layout; moreover, the multi-motor drive assembly can achieve oil-water composite cooling of the reducer 3 without integrating the drive motor 2 and reducer 3 housings, greatly improving the cooling effect of the reducer 3 and increasing its efficiency while reducing costs.

[0045] like Figure 3 As shown, preferably, at least one of the reducer cooling water passage 31 and the cooling oil passage is provided with a heat exchange groove recessed towards the other. In this embodiment, a heat exchange groove is provided on at least one of the reducer cooling water passage 31 and the cooling oil passage to increase the heat exchange area of ​​the cooling water in the reducer cooling water passage 31 and the oil in the cooling oil passage, thereby optimizing the cooling effect.

[0046] Specifically, the heat exchange groove extends along the direction of the oil slinging of the gear 3 in the reducer, or it can extend along the radial direction of the gear or other directions, as long as the heat exchange groove can extend from one of the reducer cooling water passage 31 and the cooling oil passage to the other.

[0047] To further optimize the above technical solution, in the multi-motor drive assembly cooling system provided in the above embodiment, a first heat exchange groove 34 recessed towards the reducer cooling water passage 31 is provided on the cooling oil passage; a second heat exchange groove 33 recessed towards the cooling oil passage is provided on the reducer cooling water passage 31. In this embodiment, heat exchange grooves are provided in both the reducer cooling water passage 31 and the cooling oil passage, maximizing the heat exchange area between the cooling water in the reducer cooling water passage 31 and the oil in the cooling oil passage, resulting in better cooling performance. Of course, this application may also provide only the first heat exchange groove 34 on the cooling oil passage or the second heat exchange groove 33 on the reducer cooling water passage 31.

[0048] In the multi-motor drive assembly cooling system provided in the above embodiments, there are multiple first heat exchange slots 34 and second heat exchange slots 33, which are staggered along the axial direction of the reducer 3, such as... Figure 3 As shown, the first heat exchange groove 34 and the second heat exchange groove 33 are staggered along the axial direction of the reducer 3. In this way, the two first heat exchange grooves 34 are separated by the second heat exchange groove 33, resulting in more uniform heat exchange and optimized cooling effect.

[0049] Furthermore, the projections of the first heat exchange tank 34 and the second heat exchange tank 33 along the axis of the reducer 3 partially overlap; at this time, the fluids in the first heat exchange tank 34 and the second heat exchange tank 33 are closer together, and the wall thickness at the overlapping position of their projections is thinner, resulting in a better heat exchange effect.

[0050] In one specific embodiment, the cooling oil circuit of the above-mentioned multi-motor drive assembly cooling system includes an oil pan 32, which has an oil chamber for collecting and storing lubricating oil; a reducer cooling water circuit 31 is opened on the oil pan 32. The upper part of the oil pan 32 can store returning lubricating oil, and the lower part is provided with a separate reducer cooling water circuit 31, which connects the cooling water with the lubricating oil in the oil pan 32 to form a heat exchange, cooling the lubricating oil in the oil pan 32, thereby forming an oil-water composite cooling effect. In this embodiment, the cooling and lubrication of the reducer 3 are achieved through the circulating flow of lubricating oil in the oil pan 32, eliminating the need for a separate oil cooling circuit and simplifying the structure.

[0051] In addition, this application utilizes the rotation of the internal gear of the reducer 3 to throw the oil inside the oil pan 32 from a low level to a high level, and to send part of the oil into the motor shaft of the drive motor 2 as cooling oil through the external oil circuit connection pipe. An oil spray hole is provided on the motor shaft, and the centrifugal force of the rotating motor shaft is used to spray the cooling oil onto the stator winding area and the bearing area, forming oil cooling for the motor stator winding and lubrication for the bearing. The cooling oil inside the drive motor 2 flows back to the oil pan 32, forming an oil cooling cycle.

[0052] like Figure 1 As shown, in the multi-motor drive assembly cooling system provided in the above embodiment, in each water-cooled branch, the outlet of the water tank is connected to at least one controller cooling water circuit through an outlet pipe. A flow control valve is provided on the outlet pipe. The flow control valve is used to connect to the vehicle control unit. The vehicle control unit can control the opening degree of the flow control valve according to the corresponding loop resistance in each water-cooled branch and / or the output power of all drive motors 2.

[0053] This application can provide different cooling flow rates by controlling the opening of the flow control valve according to the different cooling circuit resistance and drive assembly output power in each water-cooled branch. Since the cooling water flowing from the motor cooling water circuit in different water-cooled branches flows through the reducer cooling water circuit 31 or directly returns to the water tank through the water tank return port, the cooling circuit resistance formed by the water-cooled branches is different, and thus the water volume requirements of different water-cooled branches are different. The vehicle control unit can control the opening of the flow control valve according to the corresponding circuit resistance in each water-cooled branch. The cooling water flows from the water tank into the outlet pipe, and the flow control valve on each outlet pipe distributes the cooling water according to the required flow rate and pressure of the water-cooled branch, which can better adapt to the cooling needs of different water-cooled branches. In addition, because the output power of all drive motors 2 in different water-cooled branches is different under different operating conditions, the heat generated by the drive motors 2 and controllers 1 in different water-cooled branches is different. The higher the output power of the drive motor 2 in the water-cooled branch, the more heat is generated by the drive motor 2 and the controller 1, and the greater the required cooling water flow. The vehicle control unit can also control the opening of the flow control valve according to the different heat dissipation requirements of all drive motors 2 in each water-cooled branch to adjust the cooling water flow in the water-cooled branch, so as to better meet the heat dissipation requirements of the multi-motor drive assembly and improve the flexibility of cooling adjustment.

[0054] like Figure 1As shown, to simplify the structure, the multi-motor drive assembly cooling system provided in this embodiment includes at least two water-cooling branches, including a first water-cooling branch and a second water-cooling branch; wherein, the outlet of at least one motor cooling water circuit of the first water-cooling branch and the return water port of the water tank are connected by a first return water pipe; the outlet of at least one motor cooling water circuit of the second water-cooling branch is connected to the inlet of the reducer cooling water circuit 31, and the outlet of the reducer cooling water circuit 31 and the return water port of the water tank are connected by a second return water pipe 5.

[0055] In this embodiment, the water cooling circuit is divided into two parallel water cooling branches. In the first water cooling branch, the cooling water in the water tank is output from the outlet, flows through at least one controller cooling water circuit and at least one motor cooling water circuit in sequence, and then flows back to the return water port of the water tank through the first return water pipe, without having to flow through the reducer 3.

[0056] like Figure 3 As shown, for ease of assembly, in the second water-cooling branch, the controller cooling water circuit and the motor cooling water circuit are connected through the first water-cooling pipe 4, and the motor cooling water circuit and the reducer cooling water circuit 31 are connected through the second water-cooling pipe 6. During cooling, the cooling water in the water tank is output from the outlet, flows through at least one controller cooling water circuit, then flows through the first water-cooling pipe 4 into at least one motor cooling water circuit, then through the second water-cooling pipe 6 into the reducer cooling water circuit 31, and finally flows back to the water tank's return port through the second return water pipe 5. It needs to flow through the reducer 3, which can cool the lubricating oil in the reducer 3's oil pan 32. After the lubricating oil is cooled, it can generate splash lubrication through the rotation of the gears themselves, and then through the guide plate, etc., it can lubricate the gears, bearings and other moving parts, and then flow back to the reducer 3's oil pan 32 for cooling.

[0057] Therefore, this embodiment only requires a portion of the water-cooled branch to flow through the reducer 3, resulting in fewer cooling pipes and a simplified structure. Of course, this application could also allow all the water-cooled branch to flow through the reducer 3.

[0058] In a specific embodiment, each water-cooled branch includes one controller cooling water circuit and two motor cooling water circuits. For example... Figure 1 As shown, in each water-cooled branch, driven by the water pump, the cooling water in the water tank is output from the outlet, flows through a controller cooling water circuit and two motor cooling water circuits in sequence, and then flows back into the water tank through the return water outlet. In this way, each water-cooled branch can simultaneously cool and reduce the temperature of one controller 1 and two drive motors 2, reducing the number of branches, ensuring the cooling effect while simplifying the structure and saving costs.

[0059] The multi-motor drive assembly cooling system provided in this embodiment is suitable for a power assembly with four high-speed drive motors 2 matched with reducers 3. Depending on the actual situation, the motor cooling water circuit of one or all water-cooled branches can also be one or other numbers to accommodate different numbers of drive motors 2 in the multi-motor drive assembly.

[0060] This application also provides a vehicle, including a multi-motor drive assembly and a cooling system for cooling the multi-motor drive assembly. The cooling system is the multi-motor drive assembly cooling system provided in any of the above embodiments, which can improve the cooling effect of the reducer 3, while reducing the space occupied and investment cost. Its advantages are brought about by the multi-motor drive assembly cooling system. For details, please refer to the relevant parts in the above embodiments, which will not be repeated here.

[0061] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0062] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0063] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0064] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0065] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0066] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A cooling system for a multi-motor drive assembly, characterized in that, It includes a water-cooled circuit and an oil-cooled circuit; wherein, the oil-cooled circuit includes a cooling oil passage disposed on the reducer of the multi-motor drive assembly; The water-cooling circuit includes: A water tank that stores cooling water and has an outlet and a return outlet; At least two controller cooling water circuits are provided on at least two controllers of the multi-motor drive assembly in a one-to-one correspondence; At least two motor cooling water circuits are provided one-to-one on at least two drive motors of the multi-motor drive assembly; The reducer cooling water circuit is installed on the reducer and can cool the cooling oil circuit. The water cooling circuit is divided into at least two water cooling branches connected in parallel. Each water cooling branch includes the outlet of the water tank, at least one controller cooling water circuit, at least one motor cooling water circuit and the return water outlet of the water tank connected in sequence. Each water cooling branch is equipped with a water pump to promote water circulation. At least one of the motor cooling water circuits and the return water inlet of the water tank are connected through the reducer cooling water circuit.

2. The multi-motor drive assembly cooling system according to claim 1, characterized in that, At least one of the reducer cooling water circuit and the cooling oil circuit is provided with a heat exchange groove that is recessed toward the other.

3. The multi-motor drive assembly cooling system according to claim 2, characterized in that, A first heat exchange groove is provided on the cooling oil line, which is recessed toward the cooling water line of the reducer. The reducer cooling water line is provided with a second heat exchange groove that is recessed towards the cooling oil line.

4. The multi-motor drive assembly cooling system according to claim 3, characterized in that, There are multiple first heat exchange slots and multiple second heat exchange slots, which are staggered along the axial direction of the reducer.

5. The multi-motor drive assembly cooling system according to claim 3, characterized in that, The projections of the first heat exchange tank and the second heat exchange tank along the axial direction of the reducer partially overlap.

6. The multi-motor drive assembly cooling system according to claim 1, characterized in that, The cooling oil circuit includes an oil pan, which has an oil cavity for collecting and storing lubricating oil; The coolant passage for the reducer is located on the oil pan.

7. The multi-motor drive assembly cooling system according to claim 1, characterized in that, In each of the water-cooled branches, the outlet of the water tank is connected to at least one of the controller cooling water circuits via an outlet pipe. A flow control valve is installed on the outlet pipe. The flow control valve is used to connect to the vehicle control unit. The vehicle control unit can control the opening degree of the flow control valve according to the corresponding loop resistance and / or the output power of all drive motors in each of the water-cooled branches.

8. The multi-motor drive assembly cooling system according to claim 1, characterized in that, The at least two water-cooled branches include a first water-cooled branch and a second water-cooled branch; Wherein, at least one outlet of the motor cooling water circuit of the first water-cooling branch and the return outlet of the water tank are connected by a first return water pipe. At least one outlet of the motor cooling water circuit of the second water-cooled branch is connected to the inlet of the reducer cooling water circuit, and the outlet of the reducer cooling water circuit and the return outlet of the water tank are connected by a second return water pipe.

9. The multi-motor drive assembly cooling system according to claim 1, characterized in that, Each of the water-cooled branches includes one controller cooling water circuit and two motor cooling water circuits.

10. A vehicle comprising a multi-motor drive assembly and a cooling system for cooling the multi-motor drive assembly, characterized in that, The cooling system is the multi-motor drive assembly cooling system as described in any one of claims 1-9.

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