Out of round
In technology, geometric shapes and cross-sections that periodically deviate from a circle or a circular movement are called out-of-round . The deviations can be brought about intentionally (e.g. in the case of an out-of-round planetary gear ), but can also result from wear and tear or friction.
As a noun, the term out-of-round is used for a closed curve, which - as can be seen in the sketch opposite - has the same diameter everywhere, but whose radii of curvature are greater than half the diameter. A non-round can be used like a wheel , but its axis of rotation rises and falls periodically as it rolls. It is used in special areas of mechanical engineering , but also for some toys , e.g. B. the Tatzelwurm to follow suit.
Planned deviations from the roundness have u. a. some special planetary gears , if a periodic component is to be impressed on a regular sequence of a movement. Thus, in a can non-circular toothed gear , the ring gear to be designed as a run-out, run on the inner three smaller non-circular gears.
Small metal parts such as piston rings or washers are also often produced in a defined non-circular manner. The piston rings of gasoline engines are only pressed into the circular shape when they are installed.
Unwanted such eccentricities arise. B. by abrasion on parts of an internal combustion engine - which, like faults in the ignition, is noticeable as uneven running - or on the wheels of rail vehicles . If the deviations of such wheels from the circular shape are correspondingly large, they are not only noticeable by rumbling , but can also be rapidly intensified by the vibrations caused .
We have our own cylindrical grinding machines that are also suitable for grinding non- circular workpieces.
See also: