A variable-speed speed-up mechanism includes: an electric device which is configured to generate a rotational driving force and a planetary gear transmission device which is configured to change the speed of the rotational driving force transmitted from the electric device to a constant-speed input shaft and a variable-speed input shaft and transmit the rotational driving force to a target to be driven via an output shaft. The electric device includes a constant-speed electric motor including a constant-speed rotor which is configured to rotate the constant-speed input shaft of the planetary gear transmission device and a variable-speed electric motor including a variable-speed rotor which is configured to rotate the variable-speed input shaft of the planetary gear transmission device.

In at least some implementations, a gear shift actuator assembly to cause gear changes in a vehicle transmission, includes an electrically operated drive member, a drivetrain driven by the drive member and having a plurality of gears arranged in a plurality of stages to provide a torque increase, an output driven by the drivetrain for rotation to cause a gear change in the vehicle transmission; and a drive feature. The drive feature is coupled to the drivetrain to permit rotation of the drivetrain without activation of the electrically operated drive member, and at least one gear stage between the motor and the drive feature provides a torque increase and at least one gear stage between the drive feature and the output provides a torque increase. In at least some implementations, the drivetrain does not include a worm gear.

When an electrical continuously variable transmission malfunctions and the operation of an engine is stopped, an automatic transmission is caused to upshift. Therefore, when the rotation of the engine is stopped as a result of a stop of the operation, an AT input rotation speed is decreased as compared to that before it is determined that there is a malfunction in the electrical continuously variable transmission. Thus, an MG1 rotation speed is decreased in absolute value as compared to when the automatic transmission is not caused to upshift, so an overspeed of a first electric motor is prevented.

Methods and systems are provided for an assembly comprising a first motor positioned on a first shaft, a second motor positioned on a second shaft, a first wet clutch selectively coupled to the first shaft, a second wet clutch selectively coupled to a drive axle, a third wet clutch selectively coupled to the first shaft, and a brake clutch fixed to a housing of the assembly. The assembly comprises a planetary gearset positioned on the second shaft having gears selectively coupled to the third wet clutch, the first wet clutch or to the brake clutch. The assembly comprises a first one-way clutch and a second one-way clutch opposing the first one-way clutch, the first one-way clutch and the second one-way clutch selectively coupled to the first shaft, where the first one-way clutch and the second one-way clutch are directly connected to two gear trains to drive a PTO shaft.

When an electrical continuously variable transmission malfunctions and the operation of an engine is stopped, an automatic transmission is caused to upshift. Therefore, when the rotation of the engine is stopped as a result of a stop of the operation, an AT input rotation speed is decreased as compared to that before it is determined that there is a malfunction in the electrical continuously variable transmission. Thus, an MG1 rotation speed is decreased in absolute value as compared to when the automatic transmission is not caused to upshift, so an overspeed of a first electric motor is prevented.