Figure 8-22.- Cam and lever steering gear

The recirculating ball is the most common type of worm and nut steering gear (fig. 8-23). In this steering gear, the nut, which is in the form of a sleeve block, is mounted on a continuous row of balls on the worm gear to reduce friction. Grooves are cut into the ball nut to match the shape of the worm gear. The ball nut is fitted with tubular ball guides to return the balls diagonally across the nut to recirculate them, as the nut moves up

Figure 8-23.- Worm and nut steering gear (recirculating ball type).

and down on the worm gear. With this design, the nut is moved on the worm gear by rolling instead of sliding contact. Turning the worm gear moves the nut and forces the sector and pitman arm shaft to turn.