Wheel hub motor
A hub motor is a motor that is built directly into a wheel of a vehicle, but it is the wheel hub. A part of the motor transmits the torque produced on the wheel, with which it rotates.
Most designs are electric wheel hub motors, but there were also internal combustion engines. In electric wheel hub motors in both indoor and outdoor runners are conceivable. Principle similar to the hub motor is the hub dynamo, an exclusively regeneratively operated electric machine as external rotor motor with drive for applications to low power.
History
Wheel hub motors came in electric vehicles for use in the 19th century. Even Ferdinand Porsche was preparing for the World Expo 1900 has be -called Lohner-Porsche electric car with steerable wheel hub motors. In the 20th century it was first experiments with hybrid drives, with an internal combustion engine to power a generator, which in turn drive the individual wheels via electric motors. This also works on trailers.
In the 1920s there was with the Megola a motorcycle with a five-cylinder rotary engine as a wheel hub drive as well as a further development, the Killinger & Freund motorcycle.
Today, electric wheel hub motors with low power levels are often used power wheelchair, with electric scooters and Pedelecs. But there are already prototypical car was presented, which are driven by means of wheel hub motors. In addition, today is the use of electric hub motors in the nose wheels of aircraft is investigated.
Properties
Main advantage of electric wheel hub motors in vehicles is against to drive concepts with a central engine of the disappearance of the classic drive train with the necessary depending on the expression of components (switching) gearbox, drive shaft, differential gears and drive shafts. Since their transmission losses are cut off, offer potential to increase the efficiency of the entire drive system. Due to the principle is to drive systems with wheel hub motors to single wheel, where the torque generated by the electric motor causes a pulling force on the wheel tread of a wheel. Although a drive on one wheel only with at least one axis then each one independently controllable hub motor is a conventional vehicle with four wheels usually possible sense, however, is to provide the right or left wheel. Wheel hub motors to other vehicle concepts are possible that are virtually impossible with a conventional drive train for space reasons. Since the drive is located directly in the wheel, vehicle concepts are conceivable, for example, where a flat surface between the wheels is completely usable for the intended use. Continue to provide propulsion concepts with wheel hub motors, among other things due to reduced rotational inertia of the drivetrain and much faster control of the drive torque significantly improved dynamics, which can be used for example for driving safety systems and vehicle dynamics control systems.
Disadvantage can increase the unsprung weight - in fact it is here to suspension only by the tire compounds - impact, causing the chassis with no changes to its interpretation will tend to be less comfortable. The hub motors are exposed compared to body-fixed central engines much more to environmental influences (eg sprays or water, dust, salt- containing media ) as well as acting in the wheel forces and accelerations. Depending on the design of heat can also be entered by the mechanical brake to the drive. This can be for example the permanent magnets used in many cases or the wheel bearings mean an additional temperature change, which is to be observed when designing the drive depending on the concept and function of the respective driving situation with temperature-sensitive components. The inherently independent way to torque position and control leads to increased demands on the functional safety of the drives or the associated control devices.
Example vehicles
Examples of vehicles with wheel hub motors as drive are
- Lohner - Porsche ( 1900)
- " Fraunhofer e-concept car type 0 - Frecc0 " of the Fraunhofer Society (2011)
- Brabus High Performance 4WD Full Electric Concept Car (2011)
- The battery bus BYD ebus
- Solar vehicles like the SolarWorld GT
- Keio University Eliica