Damper hub experimental 3D model

A suspension stem pulls two counter-wound steel bands on a drum. The drum is the ring of an Ikona-style pair, run backwards as a ~20:1 speed increaser; its pinion plates do not rotate, but orbit on crankshafts journalled in the housing. The central eccentric shaft carries the rotor of a switched-reluctance machine whose windings and inverter sit on the housing. As a shock absorber the machine must make the force, which a small rotor cannot; as a J-damper (an inerter, with a flywheel) the geared inertance makes the force, and the machine only damps and recovers energy. Teeth from the ikona-style library (demo, README-servo). Drag to orbit, scroll to zoom; hover for part names.

Gears

Motion

Role, machine and control

View

Now

Sizing

Inertance b is the apparent mass the hub adds at the stem: b = J (N/r)² for parts turning with the eccentric, J/r² for the drum. Torque capability assumes the given peak torque per rotor volume (TRV; air-cooled industrial machines are rated roughly 7–30 kN·m/m³ continuous). A rotor sized just to the peak torque has b ≈ ρF²/(2πLη²σ²) at length L and TRV σ, whatever the ratio or drum: the ratio sets its speed and radius, its length and the force set the inertance.

As a J-damper the inertance is the point: a flywheel of inertia J adds J (N/r)², so b can be tens to thousands of times the mass of the moving parts. The inertial force b·a then passes through the teeth and bands (size them for the peak acceleration), backlash and friction distort it, and the machine only damps or tunes. With no magnets, an unexcited SR machine adds neither drag nor cogging: the device falls back to a pure inerter. Steel throughout; bearings, bands and stem not counted. Not a validated design.