Transmission

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two-stage gear drive with countershaft (above)
Three-speed sliding gear with direct gear. The countershaft is under the main shaft, in direct gear it runs idle.

A countershaft is an additional translation stage at a switching gear , as for example in vehicles and machine tools can be used. As a rule, countershafts reduce the speed of the driven shaft and increase the available torque . They can be switchable, often not under load (with synchronization or in operation), but only when the shafts are stationary. The back gears on trucks that are designed as "planetary axles " with epicyclic gears or as spur gears on portal axles cannot be shifted.

In vehicles, switchable cross-country gears are used to adapt the gear ratio to different operating modes, for example driving on level roads on the one hand and on the mountain or in pathless terrain on the other. These back gears are often combined with the center differential.

In lathes , the speed of the spindle is greatly reduced for thread cutting with a reduction gear.

Gear manual transmission in vehicles with front engine and rear-wheel drive have concentric input and output shafts. In addition to direct gear, two gear ratios work with a parallel countershaft .

literature

  • Heinrich Dubbel: paperback for mechanical engineering. 6th edition, Springer Verlag, Berlin / Heidelberg 1935.
  • Johannes Looman: gear transmission. Basics - constructions - applications in vehicles, 3rd edition, Springer Verlag, Berlin / Heidelberg 1996, ISBN 978-3-540-89459-9 .
  • Hans Rögnitz: Step gears on machine tools with a circular main movement. 2nd edition, Springer Verlag, Berlin / Heidelberg 1944.
  • Hans Christoph von Seherr-Thoss: The development of gear technology. Tooth shapes and load capacity calculation, Springer Verlag, Berlin / Heidelberg 1965.

annotation

  1. Gearbox of a lathe with back gear. Retrieved February 15, 2017 (3rd picture).