WO2022135082A1

WO2022135082A1 - Drivetrain system for an electrified vehicle

Info

Publication number: WO2022135082A1
Application number: PCT/CN2021/134422
Authority: WO
Inventors: Yejin JIN; Kai Chen; Guoqiang Sun
Original assignee: Valeo Powertrain (Nanjing) Co., Ltd.
Priority date: 2020-12-25
Filing date: 2021-11-30
Publication date: 2022-06-30
Also published as: CN114688217A

Abstract

The present disclosure relates to a drivetrain system for an electrified vehicle. The drivetrain system comprises an electric motor configured for providing with drive power, a transmission configured for speed-reducing and increasing torque received from the electric motor. The transmission comprises a housing and a plurality of rotating devices arranged within the housing. The drivetrain system further comprises a first retaining section configured for providing the plurality of rotating devices with lubricant for passive lubrication and for providing the housing with coolant for heat dissipation, a second retaining section configured for providing the plurality of rotating devices with lubricant for active lubrication; and a fluid level balancing apparatus configured for providing fluid communication between the first retaining section and the second retaining section. The present disclosure also relates to an electrified vehicle

Description

DRIVETRAIN SYSTEM FOR AN ELECTRIFIED VEHICLE

FIELD OF THE INVENTION

Embodiments of the present disclosure relate generally to a drivetrain system for an electrified vehicle, especially for an improved lubrication for the drivetrain system.

BACKGROUND OF THE INVENTION

The trend towards designing and building fuel efficient, low emission vehicles has increased dramatically, this trend driven by concerns over the environment as well as increasing fuel costs. At the forefront of this trend has been the development of electrified vehicles, such as BEV ( “Battery Electric Vehicle” ) , HEV ( “Hybrid Electric Vehicle” ) , PHEV ( “Plug-in Hybrid Electric Vehicle” ) , Range extended EV, FCEV ( “Fuel Cell Electric Vehicle” ) etc., electrified vehicles that combine a relatively efficient combustion engine with an electric drive motor. Electrified vehicles can include rotating components, particularly the drivetrain system, that needs to be lubricated to achieve a long service life of the rotating components. Generally, in order to achieve an adequate supply of lubricant, the differential comprised of the drivetrain system includes a reservoir containing lubricant to be transferred to the rotating components all over the drivetrain system for lubrication via at least one rotating component that is comprised of the differential and contacts with the lubricant, the lubricant however shall be always kept in a high level in the reservoir of the differential, therefore, the churning loss of the differential wheel and the power loss of the entire drivetrain system would be high.

Therefore, it would be desirable if any improvements on lubrication design for the drivetrain system for electrified vehicles could be provided at least with simple configuration, low energy consumption or loss, and low cost.

SUMMARY OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In accordance with one aspect disclosed herein, a drivetrain system for an electrified vehicle is provided. The drivetrain system comprises an electric motor configured for providing with drive power, a transmission configured for speed-reducing and increasing torque received from the electric motor. The transmission comprises a housing and a plurality of rotating devices arranged within the housing. The drivetrain system further comprises a first retaining section configured for providing the plurality of rotating devices with lubricant for passive lubrication and for providing the housing with coolant for heat dissipation, a second retaining section configured for providing the plurality of rotating devices with lubricant for active lubrication; and a fluid level balancing device configured for providing fluid communication between the first retaining section and the second retaining section.

In one embodiment, the fluid level balancing apparatus is configured to transfer the lubricant from the second retaining section to the first retaining section for further providing at least one of the plurality of rotating devices with passive lubrication, and the lubricant will be further transferred back to the section retaining section through the operation of the at least one of the plurality of rotating devices.

In one embodiment, the first and second retaining sections are separately provided within the housing of the transmission.

In one embodiment, the fluid level balancing apparatus is provided onto an abutment area between the first and second retaining sections.

In one embodiment, the fluid level balancing apparatus is disposed onto a lower portion of the abutment area.

In one embodiment, the fluid level balancing apparatus is formed by an aperture configured for making a natural balance of the fluid level of the first and second retaining sections.

In one embodiment, a pumping device including a mechanical pump configured for transferring lubricant from the second retaining section, the mechanical pump being integrated with the transmission so that it only works when the electrified vehicle runs.

In one embodiment, a pumping device including an electrical pump configured for transferring lubricant from the second retaining section when the electrified vehicle runs or stops.

In one embodiment, the plurality of rotating devices comprise a driving pinion (12) configured for transferring the drive power from the electric motor, and a differential gear (11) configured for receiving the drive power transferred from the driving pinion (12) ,

and wherein lubricant transferred from the second retaining section to the first retaining section through the balancing apparatus is provided the differential gear with passive lubrication, the differential gear (11) will bring the lubricant from the first retaining section to splash it towards the housing and at least the driving pinion so that the lubricant is transferred back to the second retaining section from the first retaining section.

In accordance with another aspect disclosed herein, an electrified vehicle comprising the above-mentioned drivetrain system is provided.

These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following detailed description. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 is a schematic view of a drivetrain system in accordance with an exemplary aspect of the present disclosure, showing the fluid level of the first and second retaining sections after long stop of the electrified vehicle; and

FIG. 2 is a schematic view of a drivetrain system in accordance with an exemplary aspect of the present disclosure, showing the fluid level of the first and second retaining sections when the electrified vehicle is moving.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made to in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “a” , “an” and “the” are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. The terms “comprising” , “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The terms “first” and “second” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of individual components.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures, FIGs 1 through 2 show a drivetrain system 100 in accordance with embodiments of the present disclosure. More particularly, the drivetrain system 100 is generally integrated with an inverter (not shown) , an electric motor (not shown) and a transmission 10. Specifically, the electric motor is contained in one housing, the transmission 10 is contained in another housing 13. The two housings can be one-piece or be formed by an assembly of housing sub-parts together.

The electric motor can be a synchronous motor or an asynchronous motor. When it is a synchronous motor, it may include a wound rotor or a permanent magnet rotor. The nominal power supplied by the electric motor can be between 10 KW and 300 KW, for example, of the order of 15 KW, for a nominal supply voltage of 48V to 350V, or up to 800V for higher power. In the case of an electric motor adapted to a high voltage supply, the nominal power supplied by this electric motor may be 300 KW. In the illustrated embodiment, the electric motor is a synchronous motor with permanent magnets, providing a nominal power between 10 KW and 300 KW. The electric motor can include a stator with a three-phase winding, or a combination of two three-phase windings or five-phase windings. Furthermore, the electric motor can include a driveshaft driven by the electrical power generated from the electromagnetic effect of a rotor and a stator included in the electric motor.

The inverter can be attached by the electrical wires to the electric motor. The inverter converts the direct current ( “DC” ) supplied by an electrical energy storage unit providing with the electric energy of a nominal voltage to the alternating current ( “AC” ) used to the electric motor 1. The inverter can be, without limitation, field effect transistors ( “FETs” ) , metal oxide semiconductor field effect transistors ( “MOSFETs” ) or insulated gate bipolar transistors ( “IGBTs” ) . In the case of a nominal supply voltage of 48V, the inverter can be MOSFET transistors. In the case of a supply voltage corresponding to a high voltage, the inverter can be IGBTs.

The transmission 10 is coupling to the electric motor. The transmission can transform the electric motor’s high speed, low torque to low speed, high torque. The transmission may comprise a plurality of rotating devices, such as reduction gear sets with different ratios and connecting with the electric motor, with one of the gears driven by the electric motor for instance, for torque increasing via speed reduction. The transmission may further comprise an intermediate shaft, linking a driving gear driven by a driveshaft and another gear of larger diameter coupled to a differential apparatus for distributing speed-reduced drive power to driven wheels of an electrified vehicle.

In the illustrated embodiment, the transmission 10 further comprises two reduction gears sets, including a driving pinion 12 and an intermediate gear 14. The driving pinion 12 can receive the drive power form the electric motor through the driveshaft, the intermediate gear 14 can receive the drive power from the driving pinion 12 through the intermediate shaft and further transfer the drive power to the differential apparatus including a differential gear 11.

There are at least one reservoir containing lubricant, e.g., oil, to be transferred to the rotating components all over the drivetrain system 100 for lubrication as well as heat dissipation for the housing. In the illustrated embodiment, the reservoir comprises a first retaining section 30 and a second retaining section 40 which are disposed at a lower portion of the housing. Specifically, the first retaining section 30 contains at least a part of the differential gear 11, so that the differential gear 11 can contact with the lubricant in the first retaining section 30, further can carry the lubricant and splash it towards the other rotating components, such as the driving pinion 12 and the intermediate gear 14 to achieve passive lubrication, as well as towards the surface of the housing 13 to achieve heat dissipation when the differential gear 11 rotates. The second retaining section 40 is adjacent to the first retaining section 30, further, an abutment area 34 is arranged between the first and

second retaining section

30, 40 so that the first and

second retaining section

30, 40 may respectively contain lubricant with different level. The second retaining section 40 is configured for providing lubricant for, for example a pumping device which is used to transfer the lubricant from the second retaining section to the rotating components all over the drivetrain system 100 for achieving active lubrication. Furthermore, such active lubrication operation may give the differential gear 11 additional or sufficient lubricant if there is not sufficient lubricant from the first retaining section 30.

Still in the illustrated embodiment, a fluid level balancing apparatus 50 is provided onto the abutment area 34 between the first and

second retaining sections

30, 40. In one embodiment, the fluid level balancing apparatus 50 is disposed onto a lower portion of the abutment area 34. The fluid level balancing apparatus 50 can be in the form of an aperture so that a natural balance of the fluid level of first and second retaining sections can be achieved, particularly during a long stop of the electrified vehicle.

In one embodiment, the pumping device is a mechanical pump 20 which is integrated with the intermediate shaft and only works when the electrified vehicle runs. Referring to Fig. 2, while the electrified vehicle is moving, the mechanical pump 20 can be driven to transfer the lubricant from the second retaining section 40 to several nozzles or fluid channels 60 disposed adjacent to the rotating components, such as driving pinion 12, the intermediate gear 14 and the differential gear 11 so as to provide active lubrication, the fluid level L2 of the second retaining section 40 may keep as a fixed value, in the meantime, the differential gear 11 is driven to carry the lubricant from the first retaining section 30 and have the lubricant splash towards the other rotating components, such as the intermediate gear 14 and the driving pinion 12, as well as towards the surface of the housing 13. Thus, the lubricant will be transferred from the first retaining section 30 to the second retaining section 40 because of such splashing, and the lubricant level L1 of the first retaining section 30 will reduce and keep as a very low level causing insufficient lubricant to be fed to the differential gear 11. Having the aperture feeding the oil from the second retaining section 40 will allow continuing the passive lubrication of the differential gear 11 with the minimum level of the oil and realizing oil splashing on the housing at the same time, therefore, limiting the oversizing of the oil pump to ensure the active lubrication at high speed of rotation.

Referring to Fig. 1, when the electrified vehicle stops and after a long stop, thanks for the fluid level balancing apparatus 50, a natural balance of the fluid level of the first and

second retaining sections

30, 40 can be achieved, i.e., the fluid level L1’ of the first retaining section 30 will be as high as that of the second retaining section 40, so that there will be sufficient lubricant in the first retaining section 30 for at least providing the rotating components with quick passive lubrication when the electrified vehicle starts to move after a long stop.

In one embodiment, the pumping device is an electrical pump (not shown) which can be disposed outside of the housing 13. The electrical pump can be configured for transferring lubricant from the second retaining section 40, i.e., used for providing with active lubrication whenever the electrified vehicle runs or stops. This is to say, the electrical pump will be always working, i.e., keep pumping the lubricant from the second retaining section 40 so that the rotating component can be continuously lubricated, further, keep sufficient splash of the lubricant with the differential gear 11 on to the surface of the housing 13 for the heat dissipation. During a long stop of the vehicle, the electrical pump can also continue to work, since the balancing aperture can bring the lubricant from the first retaining section 30 to the second retaining section 40.

This written description uses examples to disclose the embodiments of the present disclosure, including the best mode, and also to enable any person skilled in the art to practice embodiments of the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

A drivetrain system (100) for an electrified vehicle, comprising:

an electric motor configured for providing with drive power;

a transmission (10) configured for speed-reducing and increasing torque received from the electric motor, the transmission (10) comprising

a housing (13) , and

a plurality of rotating devices (11, 12, 14) arranged within the housing;

a first retaining section (30) configured for providing the plurality of rotating devices with lubricant for passive lubrication and for providing the housing (13) with coolant for heat dissipation;

a second retaining section (40) configured for providing the plurality of rotating devices with lubricant for active lubrication; and

a fluid level balancing apparatus (50) configured for providing fluidly communicating between the first retaining section (30) and the second retaining section (40) .
The drivetrain system (100) of claim 1, wherein

the fluid level balancing apparatus (50) is configured to transfer the lubricant from the second retaining section (40) to the first retaining section (30) for further providing at least one of the plurality of rotating devices with passive lubrication, and the lubricant will be further transferred back to the section retaining section (40) through the operation of the at least one of the plurality of rotating devices.
The drivetrain system (100) of claim 1, wherein

the first and second retaining sections (30, 40) are separately provided within the housing (13) of the transmission.
The drivetrain system (100) of claim 1, wherein

the fluid level balancing apparatus (50) is provided onto an abutment area (34) between the first and second retaining sections (30, 40) .
The drivetrain system (100) of claim 4, wherein

the fluid level balancing apparatus (50) is disposed onto a lower portion of the abutment area (34) .
The drivetrain system (100) of claim 1, wherein

the fluid level balancing apparatus (50) is formed by an aperture configured for making a natural balance of the fluid level of the first and second retaining sections (30, 40) .
The drivetrain system (100) of claim 1, further comprising

a pumping device (20) including a mechanical pump configured for transferring lubricant from the second retaining section (40) , the mechanical pump being integrated with the transmission (10) so that it only works when the electrified vehicle runs.
The drivetrain system (100) of claim 1, further comprising

a pumping device (20) including an electrical pump configured for transferring lubricant from the second retaining section (40) when the electrified vehicle runs or stops.
The drivetrain system (100) of claim 1, wherein

the plurality of rotating devices comprise a driving pinion (12) configured for transferring the drive power from the electric motor, and a differential gear (11) configured for receiving the drive power transferred from the driving pinion (12) ,

and wherein lubricant transferred from the second retaining section (40) to the first retaining section (30) through the balancing apparatus (50) is provided the differential gear (11) with passive lubrication, the differential gear (11) will bring the lubricant from the first retaining section (30) to splash it towards the housing (13) and at least the driving pinion (12) so that the lubricant is transferred back to the second retaining section (40) from the first retaining section (30) .
An electrified vehicle, comprising the drivetrain system (100) according any one of claims 1 to 9.