KR20230004491A - Drivetrain systems for electric vehicles - Google Patents

Abstract

The present disclosure relates to a drivetrain system for an electric vehicle. The drivetrain system includes an electric motor configured to provide drive power, including a rotor and a drive shaft driven by the rotor; a speed reducer configured for speed reduction and increase in torque received from the drive shaft, comprising an intermediate transmission shaft and at least two reduction gear sets; a differential configured to distribute the reduced drive power to the driven wheels; a detachable clutch provided on an intermediate transmission shaft, configured to provide intermittent transmission of drive power between the electric motor and the differential; A pumping component configured to deliver lubricant to provide active and continuous lubrication to the reducer, minimizing the level of lubricant with which the differential is locked.

Description

Drivetrain systems for electric vehicles

Embodiments of the present disclosure relate generally to drivetrain systems for electrified vehicles.

Concerns about the environment and concerns about rising fuel costs have led to a rapid rise in the trend towards designing and building fuel-efficient, low-emission vehicles. At the forefront of this trend has been the development of electric vehicles, such as BEVs, HEVs, PHEVs, Range Extended EVs, Fuel Cells, etc., which combine a relatively efficient combustion engine with an electric drive motor. Electric vehicles may include rotating components, particularly drivetrain systems, that need to be lubricated in order to prolong the service life of the rotating components. Generally, to achieve an adequate supply of lubricant, a differential comprising the drivetrain system is provided throughout the drivetrain system for lubrication through at least one rotating component comprising the differential and in contact with the lubricant. and a reservoir containing lubricant to be delivered to the rotating component. However, the lubricant must always be maintained at a high level in the reservoir of the differential and there is a high churning loss and differential splash loss of the differential during the cruising phase of the vehicle.

It would therefore be desirable if improvements to the lubrication design of drivetrain systems for electric vehicles could be provided, at least with simple construction, low energy consumption or loss, and low cost.

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

According to one aspect disclosed herein, a drivetrain system for an electric vehicle is provided. This drivetrain system includes an electric motor configured to provide drive power and including a rotor and a drive shaft driven by the rotor; a speed reducer comprising an intermediate transmission shaft and configured to increase torque received from the drive shaft as well as speed reduction; a differential configured to distribute the reduced drive power to the driven wheels; a disconnectable clutch provided on the intermediate transmission shaft and configured to provide an interruptive transmission of drive power between the electric motor and the differential; A pumping component configured to deliver lubricant to provide active and continuous lubrication to the reducer, minimizing the level of lubricant with which the differential locks.

In one embodiment, the reducer includes a plurality of reduction gear sets of different ratios that are connected with an electric motor and a differential.

In one embodiment, the speed reducer includes a first reduction gear set having a first drive gear connected to an electric motor and a first driven gear connected to an intermediate shaft; and a second reduction gear set having a second drive gear connected to the intermediate shaft and a second driven gear connected to the differential.

In one embodiment, the second drive gear of the second reduction gear set or the first driven gear of the first reduction gear set is rigidly connected to one of the separable clutches and the other separable clutch is rigidly connected to the intermediate shaft.

In one embodiment, the drivetrain system further includes bearings. The bearing is configured to support the separable clutch, and the second drive gear or first driven gear is rolled on a bearing disposed coaxially with the intermediate transmission shaft.

In an alternative embodiment, the reducer includes at least three gear sets of different ratios coupled with an electric motor and a differential.

In one embodiment, the separable clutch is provided coaxially to one of the at least three reduction gear sets closest to the differential or closest to the electric motor, and one gear of the at least three reduction gear sets is one gear of the separable clutch. It is firmly connected to the part.

In one embodiment, the drivetrain system further includes a bearing for supporting the separable clutch, and one gear of the at least three reduction gear sets rolls coaxially on the bearing.

In one embodiment, the drivetrain system further includes an actuator. The actuator is configured to provide an engagement force and a disengagement force to the separable clutch.

In one embodiment, the pumping component is mechanically integrated and driven by the drive shaft or intermediate transmission shaft.

In an alternative embodiment, the pumping component is electrically driven by another electric motor.

In one embodiment, the pumping component is a gerotor pump.

In one embodiment, the detachable clutch is a dog clutch.

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

A complete and possible disclosure of the present invention, including the most preferred embodiments of the present invention, which is directed to one skilled in the art, is set forth in the specification with reference to the accompanying drawings. In this drawing:
1 is a schematic diagram of a drivetrain system according to an exemplary aspect of the present disclosure.

Present embodiments of the present invention will now be described in detail, one or more examples of which are shown in the accompanying drawings. The detailed description uses numeric and letter designations to describe features of the drawings. In the drawings and description, the same or similar designations are used to refer to the same or similar parts of the invention. As used herein, the terms "a", "the" and irrelevant terms are intended to mean that there is more than one element, unless the context dictates otherwise. The terms “comprises,” “includes,” and “has” are intended to be inclusive and mean that there may be additional elements other than those listed. The terms "first" and "second" may be used interchangeably to distinguish one element from another and do not imply the location or importance of the individual elements.

Referring now to the drawings, FIG. 1 illustrates a drivetrain system 100 according to one embodiment of the present disclosure. More specifically, the drivetrain system 100 is generally integrated with an inverter (not shown), an electric motor 1 , a speed reducer 2 and a differential 3 . Specifically, the electric motor 1 is housed in one housing, and the reducer 2 and differential gear 3 are housed in another housing. The two housings can be one-piece or formed by assembling housing sub-parts together. The two housings can be securely fastened together, for example with screws. Here, a sealing wall is provided between the two housings.

The electric motor 1 may be a synchronous motor or an asynchronous motor. In the case of a synchronous motor, the motor may include a wound rotor or a permanent magnet rotor. The nominal power supplied by the electric motor may be between 10KW and 300KW (eg around 15KW) when the nominal supply voltage is between 48V and 350V (or up to 800V for higher power). In the case of an electric motor suitable for high voltage supply, the nominal power supplied by this electric motor may be 300 KW. In the illustrated embodiment, the electric motor 1 is a synchronous motor with permanent magnets and provides a nominal power of 10 KW to 300 KW. The electric motor 1 may include a stator having one three-phase winding, or a combination of two three-phase windings or five-phase windings. In addition, the electric motor 1 may include a drive shaft 11 driven by electric power generated by electromagnetic effects of a rotor (not shown) and a stator (not shown) included in the electric motor 1. can

The inverter is attached to the electric motor 1 with wires. The inverter converts direct current (“DC”) supplied by an electrical energy storage device (not shown) providing electrical energy at a nominal voltage to alternating current (“AC”) used in the electric motor. The inverter may be, but is not limited to, a field effect transistor ("FET"), a metal oxide semiconductor field effect transistor ("MOSFET"), or an insulated gate bipolar transistor ("IGBT"). If the nominal supply voltage is 48V, the inverter may be a MOSFET transistor. For supply voltages corresponding to high voltages, the inverter may be an IGBT.

Reducer (2) is connected to electric motor (1). The reducer 2 can convert high speed, low torque of the electric motor into low speed, high torque. The reducer 2 includes a plurality of reduction gear sets of different ratios which can be connected with the electric motor 1 and the differential 3, one of which is the electric motor ( 1) is driven by Reducer 2 is a gear driven by drive shaft 11 and a larger diameter coupled to differential 3 to distribute the speed-reduced drive power to driven wheel 4. It may further include an intermediate transmission shaft (21) connecting other gears of the.

In the case of the embodiment shown, the intermediate transmission shaft 21 is rotatably supported in the housing by two bearings 9 provided in the form of rolling contact bearings, each bearing positioned at the end of the intermediate transmission shaft 21. do.

Additionally, the reducer 2 may include a plurality of reduction gear sets of different ratios connected with the electric motor and the differential. In one embodiment, reducer 2 may include at least three gear sets, closest to the differential or electric to provide intermittent transmission of drive power between the electric motor 1 and the differential 3. A detachable clutch 6 may be coaxially provided on one of the at least three reduction gear sets closest to the motor. In one embodiment, one of the gears of the at least three reduction gear sets is rigidly connected to a portion of the separable clutch.

In the illustrated embodiment, the reducer 2 comprises two reduction gear sets consisting of a first reduction gear set and a second reduction gear set, the first reduction gear set comprising the electric motor 1 A first drive gear 22 connected to and a first driven gear 23 connected to the intermediate transmission shaft 21, the first drive gear 22 and the first driven gear 23 meshing with each other, The two reduction gear set includes a second drive gear 24 connected to the intermediate transmission shaft 21 and a second driven gear 25 connected to the differential 3, wherein the second drive gear 24 and the second driven gear The gears 25 mesh with each other.

In the illustrated embodiment, a pair of detachable clutches 6 are provided to provide an interruptive transmission of drive power between the electric motor 1 and the differential 3 . One of the detachable clutches 62 is arranged on the intermediate transmission shaft 21 and is further rigidly connected with the second driving gear 24 . Another one of the detachable clutches (61) is rigidly connected to the intermediate transmission shaft (21). In one embodiment, one of the detachable clutches 62 may be further rigidly connected with the first driven gear 23 . When the pair of detachable clutches 6 are engaged, the drive power of the electric motor 1 is transmitted to the vehicle via the speed reducer 2 and the clutch 6, thereby providing auxiliary drive power.

A bearing 7 is additionally provided to support the detachable clutch 6 , and the second drive gear 24 rolls on the bearing 7 arranged coaxially to the intermediate transmission shaft 21 . In one embodiment, the first driven gear 23 will roll on the bearing 7 when the clutch 6 is rigidly connected with the first driven gear 23 .

An actuator 8 is further provided to electrically provide engagement and non-engagement forces to the separable clutch 6 . In particular, the actuator 8 is disposed on the intermediate transmission shaft 21 and is mechanically connected with the clutch 61 . In one embodiment, actuator 8 may be a solenoid.

In the illustrated embodiment, the clutch 6 has fixed teeth 61 rigidly connected to the first driven gear 23 or the second driving gear 24, and rigidly connected to the intermediate transmission shaft 21. It is a dog clutch that includes a movable tooth (62). In a situation where the vehicle requires auxiliary driving power, the actuator 8 is turned on and provides an engagement force that causes the movable teeth 62 to engage the fixed teeth 61, so that the fixed teeth 61 engage the movable teeth. The toothed portion 62 is made to rotate, the intermediate transmission shaft 21 on which the teeth 61 and 62 are disposed is additionally driven to rotate, and finally the differential device 3 is driven through a reduction gear to It provides driving power to the car.

Still in the illustrated embodiment, active lubrication is provided to gearbox 2 to deliver lubricant throughout drivetrain system 100, in particular by pumping lubricant from a reservoir (not shown) included in differential 3. To do so, a pumping component 5 is additionally provided. In situations where the detachable clutch 6 is disengaged, the pumping component 5 will always work so that the electric motor can be cooled continuously. That is, it will continue to pump lubricant from the differential (3).

In one embodiment, pumping component 5 may be an electric pump that may be electrically driven by another electric motor (not shown). In one embodiment, the pumping component 5 may be a mechanical pump mechanically integrated into and driven by the drive shaft 11 or intermediate transmission shaft 21 . In the illustrated embodiment, the pumping component 5 is mechanically integrated into the intermediate transmission shaft 21 and is driven by the intermediate transmission shaft 21 so that the pumping component when the separable clutch 6 is in the disengaged state. (5) is always operated at a required speed (i.e. at a low speed) by the torque from the electric motor 1, so that the cooling and lubrication of the electric motor can be continued.

According to the drivetrain system 100 provided by the present disclosure, the use of an intermediate shaft for the disconnectable clutch allows less shock during engagement of the disengageable clutch for the high reduction ratio gearbox and the high reduction ratio gearbox and allows faster synchronization times during engagement for high-RPM electric motors, and lower force on the solenoids for detachable clutches. Also when the clutch is disengaged there will be no electrical energy loss to the electric motor flux weakening as the intermediate shaft will not transmit torque to the differential. Thanks to the active lubrication system, the oil level is kept at a low level, minimizing losses due to lubricant churning by the differential.

This written description discloses, by way of example, embodiments of the present disclosure, including the most preferred embodiments, and also allows those skilled in the art to make and use any devices or systems and perform any incorporated methods of the present disclosure, including make it possible to practice the examples. The patentable scope of the embodiments described herein is defined by the claims and may include other examples that occur to one 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 include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims (10)

In the drive train system for electric vehicles,
an electric motor configured to provide drive power, including a rotor and a drive shaft driven by the rotor;
a speed reducer configured for speed reduction and increase in torque received from the drive shaft, comprising an intermediate transmission shaft and at least two reduction gear sets;
a differential configured to distribute the reduced drive power to the driven wheels;
a disconnectable clutch provided on the intermediate transmission shaft, configured to provide intermittent transmission of drive power between the electric motor and the differential;
and a pumping component configured to deliver lubricant to provide active and continuous lubrication to the reducer.
drivetrain system. According to claim 1,
One gear of the differential is rigidly connected to the intermediate transmission shaft and torque from an electric motor operates the pumping component when the separable clutch is disengaged.
drivetrain system. According to claim 1,
The reducer includes two reduction gear sets with different ratios connected to the electric motor and the differential, the two reduction gear sets comprising:
a first reduction gear set including a first drive gear connected to the electric motor and a first driven gear connected to the intermediate transmission shaft;
a second reduction gear set comprising a second drive gear coupled to the intermediate transmission shaft and a second driven gear coupled to the differential;
The second drive gear of the second reduction gear set or the first driven gear of the first reduction gear set is rigidly connected to one part of the separable clutch, and the intermediate transmission shaft is rigidly connected to the other part of the separable clutch. connected
drivetrain system. According to claim 3,
The drivetrain system further includes a bearing for supporting the separable clutch, the second drive gear or the first driven gear being rolled on a bearing disposed coaxially on the intermediate transmission shaft.
drivetrain system. According to claim 1,
The reducer includes at least three gear sets of different ratios and is connected to the electric motor and the differential, and wherein the detachable clutch comprises at least three reduction gears closest to the differential or closest to the electric motor. provided coaxially with one of the sets, wherein one of the at least three reduction gear sets is rigidly connected to a part of the detachable clutch.
drivetrain system. According to claim 5,
The drivetrain system further includes a bearing for supporting the detachable clutch, and one gear of the at least three reduction gear sets rolls coaxially on the bearing.
drivetrain system. According to claim 1,
The drivetrain system further includes an actuator configured to provide an engaging and disengaging force to the separable clutch.
drivetrain system. According to claim 1,
wherein the pumping component is mechanically integral to and driven by the drive shaft or the intermediate transmission shaft, or electrically driven by another electric motor.
drivetrain system. According to claim 1,
The pumping component is a gerotor pump
drivetrain system. According to claim 1,
The detachable clutch is a dog clutch.
drivetrain system.

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