Patent Application
20250141304
The present application relates generally to electric drive modules for electric vehicles and, more particularly, to a two-speed electric drive module for an electrified vehicle.
Electric vehicles typically have single speed gearboxes, which while providing great torque capability on the road, are unable to provide sustained high torque for trail and sand driving or various other speeds. Such gearboxes may provide sustained high torque through higher ratio gearing, but this may not be ideal for meeting range and performance requirements for on-road and off-road usage. Moreover, such gearboxes often have relatively complex gearing arrangements and increased packaging constraints. Accordingly, while such gearing systems do work well for their intended purpose, there is a desire for improvement in the relevant art.
In accordance with one example aspect of the invention, a two-speed gearbox assembly for an electric drive module having an electric motor for an electric vehicle is provided. The gearbox assembly includes a housing, a first planetary gear set, a second planetary gear set, a first clutch, and a second clutch. The first planetary gear set includes a first sun gear, a first ring gear and a first planetary carrier. The first sun gear is configured to selectively connect to an output of an electric motor. The second planetary gear set includes a second sun gear, a second ring gear and a second planetary carrier. The second sun gear is rotationally coupled to an output of the first planetary gear set. The first clutch selectively couples the first ring gear to the housing. The second clutch selectively couples the first ring gear to an output of the electric motor.
In examples, the gearbox assembly is selectively switchable between (i) a first gear where the first clutch is engaged and the second clutch is disengaged; and (ii) a second gear where the first clutch is disengaged and the second clutch is engaged.
In addition to the foregoing, the first clutch can be configured as a brake friction clutch. In examples, first clutch can be configured as a dog clutch.
In addition to the foregoing, the second clutch can be configured as a brake friction or a dog clutch. In examples, the first clutch can be a selectable one-way clutch (SOWC).
In addition to the foregoing, the second planetary carrier can drive a final gearset comprising an input gear and an output gear. The final gearset can further comprise a parking gear. The output gear of the final gearset can be selectively coupled to drive axles through a differential
In examples, the differential is one of an electrically and mechanically locking differential. The differential can be a planetary or bevel gear type differential.
In accordance with another example aspect of the invention, an electric vehicle is provided. The electric vehicle includes an electric motor having an output shaft and first and second axle shafts. A two-speed gearbox assembly includes a housing, a first planetary gear set, a second planetary gear set, a first clutch, and a second clutch. The first planetary gear set is configured to selectively connect to an output of an electric motor and includes a first sun gear, a first ring gear and a first planetary carrier. The second planetary gear set is rotationally coupled to an output of the first planetary gear set and includes a second sun gear, a second ring gear and a second planetary carrier. The first clutch selectively couples the first ring gear to the housing. The second clutch selectively couples the first ring gear to an output of the electric motor.
In examples, the gearbox assembly is selectively switchable between (i) a first gear where the first clutch is engaged and the second clutch is disengaged; and (ii) a second gear where the first clutch is disengaged and the second clutch is engaged.
In addition to the foregoing, the first clutch can be configured as a brake clutch. In examples, first clutch can be configured as a dog clutch.
In addition to the foregoing, the second clutch can be configured as a brake clutch. In examples, the first clutch can be a selectable one-way clutch (SOWC).
In addition to the foregoing, the second planetary carrier can drive a final gearset comprising an input gear and an output gear. The final gearset can further comprise a parking gear. The output gear of the final gearset can be selectively coupled to drive axles through a differential.
In examples, the differential is one of an electrically and mechanically locking differential.
Further areas of applicability of the teachings of the present disclosure will become apparent from the detailed description, claims and the drawings provided hereinafter, wherein like reference numerals refer to like features throughout the several views of the drawings. It should be understood that the detailed description, including disclosed embodiments and drawings references therein, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the present disclosure, its application or uses. Thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure.
According to the principles of the present application, systems and methods are described for an electric drive module (EDM) of an electric vehicle (EV). The EDM includes a two-speed electric drive gearbox configured to provide a power-shift with maximum power density, efficiency, and minimum cost while maintaining NVH, reliability, durability, and shift quality. A first example of the EDM includes two planetary gearsets, a pair of multi-plate brakes, and a pair of multi-plate clutches. In additional examples, dog clutches can be provided. The EDM provides a first drive gear that is generally referred to as (range selectable) 2-LO or 4-LO and capable of meeting high torque requirements such as associated with heavy towing, trail terrain, vehicle recovery and stump removal. The EDM provides a second gear that are generally referred to as (range selectable) 2-HI or 4-HI and capable of meeting torque requirements such as associated with road and desert driving.
With initial reference to
In the example embodiment, the electric motor 20 generally includes a stator 36, a rotor 38, and a rotor output shaft 40. The stator 36 is fixed (e.g., to a housing 42) and the rotor 38 is configured to rotate relative to the stator 36 to drive the rotor shaft 40 and thus the vehicle axles 30, 32 (e.g., half shafts) and therefore respective drive wheels 50, 52. In the illustrated example, the EDM 12 is configured for a rear axle (axles 30, 32) of the vehicle 10, but it will be appreciated that the systems and methods described herein are equally applicable to a front axle EDM configuration, and can be replicated on the front and rear axles for four wheel drive.
With reference now to
In the example embodiment, the gear set 60 includes a first planetary gear set 72, and a second planetary gear set 74 and a housing 78. The two planetary gear sets 72, 74 each generally include a sun gear ‘S’, a planetary carrier ‘P’ supporting planet gears, and a ring gear ‘R’, where suffixes ‘1’, ‘2’, refer to the first and second planetary gear sets 72, 74. The gearbox assembly 22 also includes a first clutch or brake B1, and a second clutch or brake C2.
In the illustrated example, the first brake B1 and second clutch C2 are both multi-plate clutches. However, it will be appreciated that first brake B1 and/or the second clutch C2 may be any suitable type of clutch that enables gearbox assembly 22 to function as described herein. In examples, a first gear is range selectable using the first brake B1 and the second clutch C2 as dog clutches. The gearbox assembly 22 can be power shiftable with the first brake B1 used as a friction clutch or a selectable one-way clutch (SOWC) and the second clutch C2 used as a friction clutch. The final drive gearset 70 can include a lay shaft final drive having an input gear 90 and an output gear 92. Alternatively, the final drive gearset 70 can be a planetary gearset final drive including a sun gear as an input, a ring gear grounded and a carrier as an output. The exemplary final drive gearset 70 includes a parking gear 94. A clutch 96 is shown that can be selectively engaged to alter the rotation of the output gear 92 being communicated through the differential 64 and to the output shaft 32.
In the example implementation, the first planetary gear set 72 is positioned between the electric motor 20 and the second planetary gear set 74. The output shaft 40 of the electric motor 20 is rotatably coupled to the first sun gear S1 of the first planetary gear set 72. The second clutch C2 selectively connects the first sun gear S1 and the first ring gear R1.
The first Brake B1 selectively couples the ring gear R1 of the first planetary gear set 72 to the housing 78. The second planetary gear set 74 receives, at the second sun gear S2, a rotatable output 82 of the planetary carrier P1 of the first planetary gear set 72. The second ring gear R2 is fixed to the housing 78. The second carrier P2 acts as a rotatable output 84 of the second planetary gear set 74 that drives the final drive gearset 70. In particular, the rotatable output 84 drives an input gear 90 of the final drive gearset 70 that in turn drives an output gear 92. In examples, the output gear 92 serves as an input to the differential 64.
Using the EDM 12 to deliver drive torque from the electric motor 20, through the gearbox 22 and to the drive wheels 50, 52 will be described.
Description will now be made directed toward a vehicle operator selecting 2-LO or 4-LO and capable of meeting high torque requirements corresponding to first gear G1. The gearbox 22 operates in a first gear G1 by engaging the first brake B1. As used herein, “engaging” is used to mean closing a clutch to transmit torque. In examples, the first gear G1 can be associated with a 4 wheel Low drive gear setting. By engaging the first brake B1, the first ring gear R1 of the first planetary gear set 72 is grounded to the housing 78. As the first sun gear S1 is fixed for rotation with the output shaft 40 of the electric motor 20, rotation from the output shaft 40 is transferred to the first planetary gear set 72 through the sun gear S1, and the rotation is transferred to the second planetary gear set 74 via the rotatable output 82 by the carrier P1. Rotation from the second planetary gear set 74 leads to the drive wheels 50, 52 by way of the final drive gearset 70.
Description will now be made directed toward a vehicle operator selecting 2-HI or 4-HI and capable of meeting lower torque requirements and higher vehicle speeds corresponding to the second gear G2. As identified above, the second clutch C2 can be used as a friction clutch to power shift. When a second gear is desired, or to shift operation to gear G2, the second clutch C2 is engaged while the first brake B1 is released. In some examples, a shift to gear G2 can be referred to as a shift to a 4 wheel High drive gear setting. By engaging the second clutch C2 and releasing the first brake B1, the first ring gear R1 is fixed for rotation with the output shaft 40 of the electric motor 20. Rotation from the output shaft 40 is transferred to the first planetary gear set 72 through the first sun gear S1 and the first ring gear R1, and rotation is transferred to the second planetary gear set 74 via the rotatable output 82 by the carrier P1. Rotation from the second planetary gear set 74 leads to the drive wheels 50, 52 by way of the final drive gearset 70.
Described herein are systems and methods for a two-speed electric drive gearbox assembly 22 for an electric vehicle 10. The two-speed gearbox assembly 22 is configured to provide various gear ratios such as on-road and off-road gear ratios. To achieve the two-speed functionality, the gearbox assembly 22 includes two planetary gear sets 72 and 74 with selectively engageable clutches B1, and C2. As such, the described gearbox assembly 22 advantageously does not require individual electric drive modules for each wheel or complex controls/mechanisms.
It will be appreciated that the term “controller” or “module” as used herein refers to any suitable control device or set of multiple control devices that is/are configured to perform at least a portion of the techniques of the present disclosure. Non-limiting examples include an application-specific integrated circuit (ASIC), one or more processors and a non-transitory memory having instructions stored thereon that, when executed by the one or more processors, cause the controller to perform a set of operations corresponding to at least a portion of the techniques of the present disclosure. The one or more processors could be either a single processor or two or more processors operating in a parallel or distributed architecture.
It will be understood that the mixing and matching of features, elements, methodologies, systems and/or functions between various examples may be expressly contemplated herein so that one skilled in the art will appreciate from the present teachings that features, elements, systems and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise above. It will also be understood that the description, including disclosed examples and drawings, is merely exemplary in nature intended for purposes of illustration only and is not intended to limit the scope of the present application, its application or uses. Thus, variations that do not depart from the gist of the present application are intended to be within the scope of the present application.
