The worm and roller steering gear combines a space saving set-up with relatively smooth running, due to the low friction coefficient, and keeps the effort low, in comparison with the recirculating ball steering. It follows the worm and segment steering, which functions with a substantially higher amount of friction. With the worm and roller steering gear it's easier (for us nowadays) to realise the automatic returning of the steering to the center position.
The steering shaft coming in from the top left ends in the worm gear with the ball-bearings. This is known as a globoid-worm, because the diameter of the trapezoidal thread decreases towards the middle. It meshes into the cog segment lying below it. To reduce the friction as well, this is able to swivel in the roller bearings and is called the cog-roller. When steering, the fork in which the cog-roller is carried, swivels and transfers this movement further to the tie-rods.
In certain intervals the backlash of the worm and roller steering gear must be checked, if necessary, it must be readjusted by using a ring spanner and a screwdriver. 08/07