A rack and pinion mechanism converts rotational motion (from the pinion gear) into linear motion (along the rack), or vice versa. The pinion is a small cylindrical gear that meshes with the flat, toothed bar (rack).
See how rack and pinion systems compare to other common gear types across key engineering criteria.
| Feature | Rack & Pinion | Flat Gear (Rack) | Spur Gear |
|---|---|---|---|
| Noise Level | — depends on pinion size and speed | — straight tooth impact | — sudden engagement |
| Load Capacity | — direct rotary-to-linear conversion | — no shaft bending moment | — tooth root stress limits |
| Efficiency | — minimal friction in conversion | — direct linear motion | — no axial losses |
| Cost | — two matched components required | — single linear component | — simple rotary gears |
| Complexity | — requires precise center distance and alignment | — simple linear profile | — straightforward mounting |
| Typical Applications | Automotive steering, CNC machines, sliding gates, actuators | Linear axes, gate openers, positioning systems | Clocks, conveyors, pumps, machine tools |
