Wheelgear

Wheelgear is a mechanical concept in which a wheel incorporates a gear element, such that the wheel itself carries gear teeth and can engage with another gear or gear rack. This arrangement lets usable rotation be transmitted or received directly through the wheel, enabling compact drive trains and smoother meshing in some configurations. Wheelgears are found in various forms, including external teeth on the rim of a wheel, internal teeth inside a hub, or mixed arrangements where a wheel acts as both a support member and a gear element.

Construction and variants: External rim gears use teeth around the wheel circumference, engaging with a meshing pinion. Internal or hub gears place teeth inside the bore or in a carrier around the axle. Materials vary with load requirements, commonly steel, cast iron, aluminum alloys, or engineered polymers. Tooth profiles are typically spur-like for precision or modified for high torque. Some designs couple the wheel to a separate carrier or hub with minimal clearances to reduce backlash.

Applications: Wheelgears are used in compact gear drives, robotics chassis with integrated drive wheels, track-driven systems, and specialized conveyors where space or alignment favors a single rotating element bearing both wheel and gear function. They also appear in educational kits and prototype machinery for rapid assembly.

Advantages and limitations: Benefits include reduced part count, simplified alignment, and potential for compact layouts. Limitations include manufacturing complexity, wear at the meshing interface, and limited availability of standardized components compared with conventional gears.

See also: wheel, gear, gear train, spur gear, hub gear.