ball bearing

grabcad

A ball-bearing is a kind of rolling-element bearing that employs balls for separating the races, which reduces rotational friction and supports radial and axial loads. It operates by utilizing at least two races to house the balls and distribute loads via them; usually, one race remains stationary while the other is part of the moving component (like a hub or shaft). As the rotating race spins, it causes the balls to revolve too, since they have a considerably lower friction coefficient when rolling compared to sliding flat surfaces.