Spur gear

grabcad

Straight-cut gears or spur gears are the most basic types of gear. They comprise a cylindrical or disk shape with teeth projecting radially outward. Although the teeth themselves are not straight-edged (generally, they take on a special form to achieve a constant drive ratio, primarily involute but less commonly cycloidal), each tooth's edge is straight and parallel to the axis of rotation. These gears mesh perfectly only when fitted to parallel shafts. The load on the teeth does not create any axial thrust. Straight-cut gears are exceptionally effective at moderate speeds but tend to be noisy at high speeds.