Double Reduction Gear Drive

Double Reduction Gear Drive

A new design of rear axle, doing away with side driving chains, is illustrated on this page. In addition to showing the solution of an important engineering problem, this design retains the advantages of chain drive and adds advantages of its own which produce greater efficiency. In announcing the double reduction gear drive, the White company in whose apparatus the new feature has been adopted states: “The chain and Sprocket afforded in heavy duty apparatus a double reduction system -one reduction in a jackshaft and a second reduction in the chain and sprocket wheels thus giving a large range of gear ratios and, consequently, a greater flexibility than can be had in any single reduction shaft drive unless the gear housing is made very large and the rear axle, in consequence, heavy and unwieldy. Chain drive also has this advantage: Power is applied to the rear wheels on a sprocket attached to them; power is thus applied nearer to the wheel rim and by a rolling contact between the chain and sprocket. The new double reduction gear drive accomplishes the same result. There is a first reduction through the bevel gear and drive pinion in the center of the rear axle, from which the power is carried by a live axle of the floating type through the center of the housing to a gear at the wheel end of the live axle. This gear, in turn, meshes with a second gear (carried on the housing of the live axle, but inside the hub case of the rear wheel), and this second gear, in turn, meshes with a ring gear attached to the wheel inside of the hub case. In this way of applying power to the wheel, a second reduction occurs between these three gears in the hub case very similar to the reduction which takes place between the sprocket wheels of a chain drive. The power is applied at about the same distance from the rim as it is in the case of the chain drive, thereby retaining that advantage. This use of gears makes a rolling contact throughout, without any elements to produce friction. The adoption of the floating type of rear axle and the train of gears in the hub case of the wheel, enables the whole mechanism to be entirely encased and run in oil. The result is a comparatively frictionless running axle that cannot be cramped or get out of line, and has all of the operating advantages of chain drive with the added advantage in point of maintenance of being enclosed in a dust-proof case and running in oil. Chain drive had a further advantage over other types of rear axles in the fact that its unsprung weight was considerably less. The new double reduction rear axle has the same advantage in that the unsprung weight of the truck has not been increased but, in fact, decreased a little. The result will be at once apparent in the life of tires.”

Double Reduction Gear Drive.

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