Ccw Cw

FIGURE 6 Fan-cooled worm gear drive

smoother and quieter as a result of their curvature and their operating life is longer. Like straight-bevel gears, zerol gears have the advantage of no inward axial thrust under any conditions. The zero spiral angle produces thrust loads equivalent to those in straight-bevel gears.

HYPOID GEARS Hypoid-bevel gears have the general appearance of spiral-bevel gears but differ in that the shafts supporting the gears are not intersecting. The pinion shaft is offset to pass the gear shaft. The pinion and gear are cut on a hyperboloid of revolution, the name being shortened to hypoid. Hypoid gears can be made to provide higher ratios than spiral-bevel gears. They are also stronger and operate even more smoothly and quietly. The fact that two supporting shafts can pass each other, with bearings mounted on opposite sides of the gear, provides the ultimate rigidity in mounting.

worm gears In operation, the teeth on the worm of a worm gear set (Figure 6) slide against the gear teeth and at the same time produce a rolling action similar to that of a rack against a spur constant output speed completely free of pulsations. Worm gearing is particularly adaptable to service where heavy shock loading is encountered.

Worm gearing is extremely compact, considering load-carrying capacity. Much higher reduction ratios can be attained through a worm gear set on a given center distance than through any other type of gearing. Thus, the number of moving parts in a speed-reduction set is reduced to the absolute minimum. However, worm gearing is limited in power capacity and has lower efficiencies than parallel-shaft and bevel-gear types. Extremely high worm thrust loads are generated by work gearing. Therefore, never reverse the rotation unless the unit is specifically designed for operation in both directions.

Survival Treasure

Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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