Lesson 1/Learning Event 1
The worm and sector steering gear is very simple in construction. This
makes it cheap to build and easy to maintain. A disadvantage is that it has
a lot of friction because of the sliding action between the worm and sector
FIGURE 5. WORM AND ROLLER STEERING GEAR.
WORM AND ROLLER STEERING GEAR
The worm and roller steering gear is much like the worm and sector, but the
sliding friction is changed to rolling friction so that less effort is
required to turn the steering wheel. This is made possible by machining the
sector teeth on a roller. Friction is reduced even more by mounting the
roller on bearings in a saddle at the inner end of the pitman arm shaft.
The worm has an hourglass shape, smaller in the center than at the ends.
The hourglass shape makes the roller stay in better contact with the worm
teeth at the ends of the worm.