Internal gear can be a gear with its teeth cut in the internal surface area of a cylinder and meshes with spur gears.

In its manufacturing, because of its shape, the usual hobbing machine used in spur gear production can’t be used. Generally it really is made with gear shaper (or equipment shaping machine) built with a pinion cutter. Recently, the efficiency of internal gear cutting has been improved by a different process called skiving.

Due to the thinness of the band, it is sometimes difficult to produce high precision. However, gear grinding to improve precision grade is bound by the amount of producers and their obtainable grinding facilities resulting in very high cost.

Also, although it is normally too expensive to make helical teeth internal gears, Ever-Power has made it possible to create them by adopting equipment that can cut them by simply making pinion cutters rather than needing helical guides.

Normally, internal gears can be utilized with the same module spur gears, based on the amount of teeth combinations, nonetheless it is necessary to notice the possibilities to getting involute, trochoid or trimming interferences. For using Ever-Power standard share gears, please consult the PDF formatted “Technical Info of Internal Gears” section for usable amount of teeth combinations.

Internal gears are often found in applications involving planetary gear drives and gear couplings. There are three main types of planetary gear mechanisms: planetary, solar and celebrity types. With respect to the type and the pattern of which shafts become input and output, many variations of velocity tranny ratios and rotational directions are produced.