Lesson 1/Learning Event 1
FIGURE 4. WORM AND SECTOR STEERING GEAR.
WORM AND SECTOR STEERING GEAR
This type of steering gear looks a lot like our bolt and nut, but the sector
of this type looks like a gear instead of a nut. The teeth of the sector
are machined in an arc, or curve, so that they actually look like a section
of a gear.
As the steering wheel and worm turn, the worm pivots the sector and pitman
arm shaft. The sector pivots through an arc of 70 because it is stopped at
each extreme when it touches the steering gear housing.
The worm is assembled between bearings, and some means is provided to adjust
the bearings to control worm end play. The pitman arm shaft is fitted into
the steering gear housing on bearings (generally the bushing type, but
rollertype bearings are sometimes used). A lash adjustment screw is also
provided so that the sector can be moved closer to, or farther away from,
the worm gear to control the backlash between the sector and worm threads or
teeth.
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