1. Field of the Invention
The invention generally relates to drive systems for vehicles, and more particularly, to a drive system having electric wheel motors mounted to each wheel of the vehicle.
2. Discussion of the Related Art
Generally, vehicles may be powered by an internal combustion engine or one or more electric motors. Some so-called hybrid vehicles include a combination of an internal combustion engine and electric motor power. Such hybrid vehicles sometimes include parallel drive systems that provide propulsion modes from the electric motor, internal combustion engine, or both.
Typically, the mechanical coupling that allows selection between electrical or internal combustion power is mounted directly to the internal combustion engine, vehicle transmission, or a so-called summation gearbox that combines the electric drive with the mechanical drive. Such arrangements allow for a controller or the vehicle operator to select between the electrical power and the internal combustion power for driving the vehicle.
A major drawback of previous vehicles that combine the electric drive with the mechanical drive is that there is little modularity in design. The electric motor or drive may be bulky and large. Additionally, the transmission required to operate both the electric motor and internal combustion engine is complex in design.
The present invention provides an arrangement that allows for a decentralized or modular design where an electric wheel motor is mounted at each wheel. This allows for improved modularity, smaller parts, improved safety, and reduced maintenance costs.