500:1
Hypoid
Hypoid gearboxes are a type of spiral bevel gearbox, with the difference that hypoid gears have axes that are non-intersecting and not parallel. ... In a hypoid gearbox, the spiral angle of the pinion is larger than the spiral angle of the gear, so the pinion diameter can be larger than that of a bevel gear pinion.
Sprockets
Chain sprockets are teeth like projections arranged on a wheel rim to engage the links of a chain. They engage chains in many different power transmission and conveyor systems. They are mainly made of cast iron, sintered metal, and carbon steel. Inserted sprockets are also designed to reduce noise and operation.
backlash
Backlash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and to provide space for a film of lubricating oil between the teeth. This prevents overheating and tooth damage.
whole depth
WHOLE DEPTH is the total depth of a tooth space, equal to addendum plus dedendum, equal to the working depth plus variance. WORKING DEPTH is the depth of engagement of two gears; that is, the sum of their addendums.
