Page 193 - Root Cause Failure Analysis
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Gearboxes/Reducers 181
Figure 1614 Miter gear shaft angle (Neale 1993).
Miter
Miter gears are bevel gears with the same number of teeth in both gears, operating on
shafts at right angles, or 90°, as shown in Figure 14-14. Their primary use is to
change direction in a mechanical drive assembly. Since both the pinion and gear have
the same number of teeth, no mechanical advantage is generated by this type of gear.
Hvpoid
Hypoid-bevel gears are a cross between a spiral-bevel gear and a worm gear
(Figure 14-15). The axes of a pair of hypoid-bevel gears are nonintersecting and the
distance between the axes is referred to as the offset. This configuration allows both
shafts to be supported at both ends and provides high strength and rigidity.
Although stronger and more rigid than most other types of gears, they are less efficient
and extremely difficult to lubricate because of high tooth-contact pressures. Further
Figure 1415 Hypoid bevel gear (Neale 1993).
