Electrical motor transmission

A vehicle gearing system comprising:

• an electric motor;
• a final drive;
• a gearing system with two-degrees-of-freedom comprising at least three components configured to rotate one with respect to the other, said gearing system configured to transfer power from the electric motor to the final drive,
• wherein said gearing system comprises a one-way mechanism connected to one of the at least three rotating components of the gearing system, said one-way mechanism configured to reduce a degree of freedom of the two-degrees-of-freedom by restricting rotation of the one component along a first direction, during a powered driving mode of the powertrain, while said one-way mechanism is configured to enable free rotation of the one component along a second opposite direction, during coasting mode of the powertrain, thereby avoiding drag of the electric motor;
• and
• a mechanical friction brake connected to the gearing system via a component of the at least three components, said mechanical friction brake configured to reduce a degree of freedom of the two-degrees-of-freedom by restricting rotation of the component that the mechanical friction brake is connected to, to cause motion of the electric motor, during a braking mode of the powertrain, thereby regenerating energy by the electric motor;
• and
• a control system configured to control an amount of the power supplied by the electric motor during the driving mode, and to control an amount of negative torque applied by the electric motor during the regenerative braking mode, said control system comprising a processor configured to:
• detect braking mode;
• predefine a set point value based on:
• (i) transmission ratio of the vehicle and (ii) a parameter modifiable according to a required regeneration ratio, wherein the regeneration ratio represents a ratio between motor speed and final drive speed;
• calculate a process value based on an actual ratio between motor speed and final drive speed;
• and
• determine an amount of negative torque required for equality between the process value and the set point value, said negative torque to be applied by the electric motor during the regenerative braking mode;
• wherein the gearing system comprises a planetary gear, and the at least three components comprise a sun gear rotatably connected to the electric motor and to at least on planet gear, wherein said at least one planet gear is rotatably connected to a planet carrier, and
• wherein the mechanical friction brake is connected to the planet carrier, said mechanical friction brake is configured to slow rotation of the planet carrier and thus mechanical force rotation of the electric motor via forced rotation of the sun, thereby enabling regenerative braking.

A method for controlling braking mode in a vehicle, said vehicle comprising an electric motor, a final drive, and a gearing system with two-degrees-of-freedom comprising at least three components configured to rotate one with respect to the other, said gearing system configured to transfer power from the electric motor to the final drive,

• wherein said gearing system comprises a one-way mechanism connected to one of the at least three rotating components of the gearing system, said one-way mechanism configured to reduce a degree of freedom of the two-degrees-of-freedom by restricting rotation of the one component along a first direction, during a powered driving mode of the powertrain, while said one-way mechanism is configured to enable free rotation of the one component along a second opposite direction, during coasting mode of the powertrain, thereby avoiding drag of the electric motor;
• a mechanical friction brake connected to the gearing system via a component of the at least three components, said mechanical friction brake configured to reduce a degree of freedom of the two-degrees-of-freedom by restricting rotation of the component that the mechanical friction brake is connected to, to cause motion of the electric motor, during a braking mode of the powertrain, thereby regenerating energy by the electric motor and a processor;
• said method comprising:
• detecting braking mode;
• predefining a set point value based on:
• (i) transmission ratio of the vehicle and (ii) a parameter modifiable according to a required regeneration ratio, wherein the regeneration ratio represents a ratio between motor speed and final drive speed;
• calculating a process value based on an actual ratio between motor speed and final drive speed;
• and
• determining an amount of negative torque required for equality between the process value and the set point value, said negative torque to be applied by the electric motor during the regenerative braking mode.