Electric vehicle drive train with direct coupling transmission

A drive train for an electric vehicle, said drive train comprising:

• a traction battery;
• an electric motor having an output shaft and being associated with said traction battery and operable in one of a drive mode for driving one or more wheels of the vehicle and a regenerative braking mode for recharging said traction battery;
• a sensor associated with the output shaft of said electric motor for sensing a rotational speed thereof;
• transmission means connected to said electric motor and comprising an output shaft for rotatably driving one or more wheels of the vehicle, said transmission means further comprising a planetary gearbox having an input coupled to said output shaft of said electric motor for operating in a speed reduction mode, and direct coupling means for coupling said motor output shaft to said output shaft of said transmission means for operating in a direct coupled mode;
• and
• control means connected to said traction battery, said electric motor, and said transmission means, and being responsive to said sensor for operating said transmission means in said speed reduction mode when a rotational speed of said electric motor is below a first predetermined value and for operating said transmission means in said direct coupled mode when a rotational speed of said electric motor is above a second predetermined value,,., said control means comprising speed synchronizing means for operating said electric motor in said regenerative braking mode to reduce a rotational speed of said electric motor to a corresponding reduced rotational speed of said transmission means in said direct coupled mode when changing said transmission means from said speed reduction mode to said direct coupled mode.

An electric vehicle comprising:

• a frame;
• one or more wheels rotatably mounted to said frame;
• a traction battery carried by said frame;
• an electric motor connected to said traction battery and operable in one of a drive mode for driving one or more wheels of the vehicle and the regenerative braking mode for recharging said traction battery;
• sensing means associated with said electric motor for sensing rotational speed thereof;
• transmission means connected to said electric motor for rotatably driving the one or more wheels of the vehicle in one of a speed reduction mode and a direct coupled mode;
• and
• control means connected to said transmission means and responsive to said sensing means for controlling said transmission means to operate in said speed reduction mode when a rotational speed of said electric motor is below a first predetermined value and for controlling said transmission means to operate in said direct coupled mode when a rotational speed of said electric motor is above a second predetermined value, said control means comprising speed synchronizing means for operating said electric motor in said regenerative braking mode to reduce a rotational speed of said electric motor to a corresponding reduced rotational speed of said transmission means in said direct coupled mode when changing said transmission means from said speed reduction mode to said direct coupled mode.

A method for driving one or more wheels of an electric vehicle including a traction battery connected to an electric motor which is connected to the drive wheels through a transmission, the electric motor being operable in one of a drive mode for driving one or more of the drive wheels of the vehicle and a regenerative braking mode for recharging the traction battery, and the transmission being operable in either a speed reduction mode or a direct coupled mode, said method comprising the steps of:

• sensing rotational speed of the electric motor;
• operating the transmission in the speed reduction mode when a rotational speed of the electric motor is below a first predetermined value and operating the transmission in the direct coupled mode when a rotational speed of the electric motor is above a second predetermined value;
• and
• substantially synchronizing rotational speed of the electric motor and the transmission when changing the transmission from the speed reduction mode to the direct coupled mode by operating the electric motor in the regenerative braking mode to reduce a rotational speed of the electric motor to substantially match to the transmission.