US-12620867-B2 - Multispeed electric drive module actuation mechanism

Abstract

An electric drive module for an electrified vehicle includes an electric motor, a transmission and a multispeed actuation mechanism (MAM). The transmission is driven by a rotatable output of the electric motor and includes a first drive shaft and a second drive shaft. The transmission has a first gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a first gear mode at a first drive ratio, and a second gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a second gear mode at a second drive ratio, distinct from the first drive ratio. The MAM has magnetic fluid therein. Activation of the magnetic fluid causes a shift to occur within the transmission from the first gear set to the second gear set.

Inventors

• Michael E Fingerman

Assignees

• FCA US LLC

Dates

Publication Date

20260505

Application Date

20230822

Claims (6)

1. 1 . An electric drive module for an electrified vehicle, the electric drive module comprising: an electric motor having a rotatable output; a transmission that is driven by the rotatable output and includes a first drive shaft and a second drive shaft, the transmission having: a first gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a first gear mode at a first drive ratio, the first gear set comprising a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively drive the second drive shaft in the first gear mode; and a second gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a second gear mode at a second drive ratio, distinct from the first drive ratio, the second gear set comprising a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively rotate with the second drive shaft in the second gear mode; and a multispeed actuation mechanism (MAM) having magnetic fluid including ferromagnetic nanoparticles suspended therein wherein activation of the magnetic fluid causes first and second disks within the MAM to move from a disengaged position to an engaged position to couple for rotation the first drive shaft with the first gear of the second drive gear set and a shift to occur within the transmission from the first gear set to the second gear set, wherein the first drive shaft is coaxial with the first gear of the second gear set such that in the disengaged position, the first drive shaft rotates within the first gear of the second gear set.
2. 2 . The electronic drive module of claim 1 , wherein the MAM is configured to receive an activation signal from a controller based on sensor inputs of the electrified vehicle indicative of a shift change request.
3. 3 . The electronic drive module of claim 1 , wherein the second drive shaft is rotatably coupled to drive axles that drive respective drive wheels through a differential.
4. 4 . An electric drive module for an electrified vehicle, the electric drive module comprising: a transmission that is driven by an output of an electric motor and includes a first drive shaft and a second drive shaft, the transmission having a first gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a first gear mode at a first drive ratio, the first gear set comprising a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively drive the second drive shaft in the first gear mode; and a second gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a second gear mode at a second drive ratio, distinct from the first drive ratio, the second gear set comprising a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively rotate with the second drive shaft in the second gear mode; and a multispeed actuation mechanism (MAM) having magnetic fluid including ferromagnetic nanoparticles suspended therein, the MAM further having a first disk rotatably coupled to the first drive shaft and a second disk rotatably coupled to the first gear of the second gear set, wherein activation of the magnetic fluid causes the first and second disks to rotate concurrently and a shift to occur within the transmission from the first gear set to the second gear set, wherein the first drive shaft is coaxial with the first gear of the second gear set such that deactivation of the magnetic fluid results in the first drive shaft to rotate within the first gear of the second gear set.
5. 5 . The electronic drive module of claim 4 , wherein the MAM is configured to receive an activation signal from a controller based on sensor inputs of the electrified vehicle indicative of a shift change request.
6. 6 . The electronic drive module of claim 4 , wherein the second drive shaft is rotatably coupled to drive axles that drive respective drive wheels through a differential.

Description

FIELD The present application generally relates to electrified vehicles and, more particularly, to an electric drive module that uses an actuation mechanism having magnetic fluid to initiate a shift change. BACKGROUND An electrified vehicle (hybrid electric, plug-in hybrid electric, range-extended electric, battery electric, etc.) includes at least one battery system and at least one electric motor. Typically, the electrified vehicle would include a high voltage battery system and a low voltage (e.g., 12 volt) battery system. In such a configuration, the high voltage battery system is utilized to power at least one electric motor configured on the vehicle and to recharge the low voltage battery system via a direct current to direct current (DC-DC) convertor. Electrified vehicles generally include a powertrain configured to generate and transfer drive torque to a driveline of the vehicle for propulsion. The electrified powertrain generally comprises the high voltage battery system, one or more electric motors, and a transmission. The electric motors and transmission can be referred to as an electric drive module. Some electric drive modules can incorporate conventional clutch systems that allow the transmission to shift between more than one gear. Conventional clutch systems require components such as a pump, valves, solenoids to support its functions. These components can result in a power loss of the electrified powertrain as a whole. Accordingly, while such electric drive modules having transmissions using conventional clutch systems do work well for their intended purpose, there exists an opportunity for improvement in the relevant art. SUMMARY According to one example aspect of the invention, an electric drive module for an electrified vehicle includes an electric motor, a transmission and a multispeed actuation mechanism (MAM). The transmission is driven by a rotatable output of the electric motor and includes a first drive shaft and a second drive shaft. The transmission has a first gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a first gear mode at a first drive ratio, and a second gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a second gear mode at a second drive ratio, distinct from the first drive ratio. The MAM has magnetic fluid therein. Activation of the magnetic fluid causes a shift to occur within the transmission from the first gear set to the second gear set. In some implementations, the magnetic fluid includes ferromagnetic nanoparticles suspended therein. The MAM is configured to receive an activation signal from a controller based on sensor inputs of the electrified vehicle indicative of a shift change request. In some implementations, the MAM further includes a first disk and a second disk. Activation of the magnetic fluid results in the first and second disks moving from a disengaged position to an engaged position. The first gear set comprises a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively drive the second drive shaft in the first gear mode. The second gear set comprises a first gear configured to rotate with the first drive shaft and a second gear that is configured to selectively rotate with the second drive shaft in the second gear mode. In additional arrangements, the first and second disks engage to couple for rotation the first drive shaft with the first gear of the second gear set. The second drive shaft is rotatably coupled to drive axles that drive respective drive wheels through a differential. According to another example aspect of the invention, an electric drive module for an electrified vehicle includes a transmission and a multispeed actuation mechanism (MAM). The transmission is driven by a rotatable output of an electric motor and includes a first drive shaft and a second drive shaft. The transmission has a first gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a first gear mode at a first drive ratio, and a second gear set that selectively converts rotatable motion of the first drive shaft into rotatable motion of the second drive shaft in a second gear mode at a second drive ratio, distinct from the first drive ratio. The MAM has a first disk rotatably coupled to an input shaft and a second disk rotatably coupled to an output shaft. The MAM includes magnetic fluid therein. Activation of the magnetic fluid causes the first and second disks to rotate concurrently and a shift to occur within the transmission from the first gear set to the second gear set. In some implementations, the magnetic fluid includes ferromagnetic nanoparticles suspended therein. The MAM is configured to receive an activation signal from a controller based on sensor inputs of the electrified ve