Hydrodynamic bearings put the squeeze on balls

A new series of hydrodynamic pressure bearings from Sterling Instrument feature a 30% weight saving along with lower cost when compared with conventional ball bearings. They fulfill the need for a long-lasting bearing capable of high speed, quiet operation and suitable for light application use, such as compact fan motors, paper feeders in copying machines and printers, laptop computers, micromotors etc. The bearings, identified as the S99HDPM Series, are formed by stacking 'petal shaped' laminated aluminium-silicon alloy plates that are housed in a stainless steel case with a polyurea-thickened grease containing antioxidant and anticorrosion additives. The inner faces of these laminated plates act as the bore of the assembled bearing. When the shaft rotates in this state, a fluid between the shaft guide and the shaft generates pressure as a result of the 'squeeze effect' - a phenomenon of generating pressure to a lubricating membrane in a fluid lubrication when wall faces are close to each other. The seven bearings in the series have inside diameters ranging from 1 to 6mm and an impressive maximum speed range of from 6000 to 20,000rev/min. Detailed specifications are contained in SI catalogue 785 available free on request from Sterling Instrument.