Page 187 - Root Cause Failure Analysis
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GearboxeslReducers 175
Fiere 14-3 Rack or straight-line gear (Neale 1993).
from the sliding contact of the meshing teeth. A disadvantage, however, is the higher
friction and wear that accompanies this sliding action.
Single helical gears are manufactured with the same equipment as spur gears, but the
teeth are cut at an angle to the axis of the gear and follow a spiral path. The angle at
which the gear teeth are cut is called the helix angle, which is illustrated in
Figure 14-5. This angle causes the position of tooth contact with the mating gear to
vary at each section. Figure 14-6 shows the parts of a helical gear.
Figure 14-4 Qpical set of helical gears (Neale 1993).