THE ECONOMICAL LINEAR GUIDE
Ball bushes are a mainstay of many linear motion applications. They offer low friction linear guidance at an economical price. A ball bush really comes into its own with light to moderate load, short unsupported travel lengths and modest precisions. Ball bushes are found in a wide variety of applications including measuring equipment, drilling machines, punching presses, printing and food packaging.
A basic ball bush has a cylindrical outer formed from bearing steel. The outer shell has cylindrical grooves and is precision ground to fit into a housing and retained with either internal circlips inside the housing bore or external circlips on the outer shell of the ball bush. Alternatively flanged bushes feature counter bored holes around an integral external flange for axial fastening.
Internally an engineering plastic retainer guides the balls in a recirculating path. The retainer recirculates the balls at each end of the bush between the internal unloaded return tubes and the loaded section. The recirculation of the balls means the travel length of the bush is only limited to the shaft it runs on. For more demanding applications a super ball type is available. This type has an engineering plastic shell with crowned bearing steel inserts at the ball loading regions. The construction has self aligning properties and allows the use of larger balls which give a longer service life.
t is important that ball bushes are run on suitable hardened and ground shafting. Hardeness of at least HrC55 and a ground tolerance of g6 is generally recommended. Common bright mild, extruded shafts with not have sufficient accuracy and hardeness and will suffer from fatigue flaking after only a short service life.
Linear motion have NZ’s best range of industry standard ball bushes and shafting and can offer an integrated solution of bushes with case units, hardened shafting and supports. We also have many years experience in linear systems and are happy to assist in specifying suitable guidance systems.
More details on ball bushes can be found on this page of our website. Or give us call to discuss any projects you may be working on.