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Gear train. Transmission of motion and force by gear wheels, compound train. [1] Illustration by Georgius Agricola (1580) showing a toothed wheel that engages a slotted cylinder to form a gear train that transmits power from a human-powered treadmill to mining pump. A gear train or gear set is a machine element of a mechanical system formed by ...
Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer, or planet, gears or pinions, revolving about a central sun gear or sun wheel. [4][5] Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear.
A bicycle gearbox with chain tensioner. Bicycle gearing is the aspect of a bicycle drivetrain that determines the relation between the cadence, the rate at which the rider pedals, and the rate at which the drive wheel turns. On some bicycles there is only one gear and, therefore, the gear ratio is fixed, but most modern bicycles have multiple ...
The golden spiral is a logarithmic spiral that grows outward by a factor of the golden ratio for every 90 degrees of rotation (pitch angle about 17.03239 degrees). It can be approximated by a "Fibonacci spiral", made of a sequence of quarter circles with radii proportional to Fibonacci numbers .
Contents. Differential (mechanical device) A differential is a gear train with three drive shafts that has the property that the rotational speed of one shaft is the average of the speeds of the others. A common use of differentials is in motor vehicles, to allow the wheels at each end of a drive axle to rotate at different speeds while cornering.
Depending on the gear ratio of the bicycle, a (torque, angular speed) input pair is converted to a (torque, angular speed) output pair. By using a larger rear gear, or by switching to a lower gear in multi-speed bicycles, angular speed of the road wheels is decreased while the torque is increased, product of which (i.e. power) does not change.
Typical gear ratios on bicycles range from very low or light gearing around 20 gear inches (1.6 metres per revolution), via medium gearing around 70 gear inches (5.6 m), to very high or heavy gearing around 125 gear inches (10 m). As in a car, low gearing is for going up hills and high gearing is for going fast.
Worm-and-gear sets are a simple and compact way to achieve a high torque, low speed gear ratio. For example, helical gears are normally limited to gear ratios of less than 10:1 while worm-and-gear sets vary from 10:1 to 500:1. [45] A disadvantage is the potential for considerable sliding action, leading to low efficiency. [46]