tech talk
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Here are some options of how to achieve anti-rotation features:
Careful material selection and strategic design are vital for securing bearings against moving out of
housing bores. Different design choices for securing bearings are covered in part two of this series.
Option 1: Anti-rotation with holes in the flange
By drilling holes in the flange (or implementing them in the injection mold), the simple holes can serve
as an anti-rotation feature. Screws are simply put inside to fix the bearing to the housing. For higher
quantities, this design is not the best, since assembly requires manual labor and is therefore more time
consuming. On top of that, the costs for screws for each bearing need to be factored in.
Option 2: Anti-rotation features with simple form-fit on the outer diameter
Simple, reliable and cost-effective measures can
be taken to keep bearings in place. Form-fit means
that the bearing shape itself serves as an anti-
rotation feature. This can be achieved by changing
the round outer shape of a bearing into something
with an edge, or any other protruding feature. The
cost increase for an according injection mold is
relatively low. It should be considered, however,
that a corresponding shape in the housing hole
will be needed. For automated assembly, it may be
necessary to make sure the bearings are always
properly aligned with the housing hole.
Bearing with fixation holes in the flange
Form-fit anti-rotation feature on the outer diameter
Plastic plain bearings can be made in almost any shape or form. The limitations of metal/bronze/
PTFE bearings, such as sheet metal thicknesses or the necessity of lubrication grooves do not exist.
Furthermore, manufacturing technologies like injection-molding, 3D printing, sintering and machining of
barstock materials allow users to design with few limitations.
Free design choices with plastic bearings
