Angle Measuring System is Bearing-integrated(Schaeffler)

Angle Measuring System is Bearing-integrated(Schaeffler) At the recent EMO 2007 show, the Schaeffler Group Industrial showed a bearing-integrated YRTSM angle measuring system. For use in dynamic and precise direct-drive rotary machine tool axes the YRTSM is integrated into the high-speed YRTS rotary table bearing series, which offers extremely high tilting rigidity and low friction.The resulting YRTSM range is available with bore diameters from 200mm up to 460mm. Depending on the bearing size, bearing limiting speeds and measuring limiting speeds of between 560 and 1,160 rev/min can be achieved.The output signal properties provided by the measuring system enable very rigid and highly dynamic drive control.Thanks to these characteristics, the bearing/measuring system unit is particularly suitable for rotary axes that are used for milling and turning operations. Integration of the angle measuring system into the bearing enables not only produces more compact designs but also a free bearing centre. For example, it permits the space-saving accommodation of supply lines.Moreover, it requires no installation ancillaries for attaching the measuring system and measuring system alignment. The magnetic dimensional scale, which resists contamination against greases, oils and emulsions, is jointlessly metal-to-metal bonded to the rotating bearing shaft locating. Two sensor heads, offset by 180 deg and diametrically arranged relative to each other, undertake magnetoresistive, non-contact scanning of the washer.In this way, the system compensates for eccentricity caused by machining forces and achieves an absolute measuring accuracy better than +/-3 min of arc and a repeatable accuracy better than 1 micron.Moreover, the procedure doubles the angular resolution that grows with increasing bearing diameter. Both measuring heads are rigidly flanged to the rotary table structure.The rigid connection of the dimensional scale to the rotating rotary table and the robust, vibration-stable connection of the measuring heads to the basic structure enable supreme quality and rigidity of control.The plug connection at the measuring heads simplifies cabling, resulting in cost reductions in design, procurement and installation. The metal housing and seals protect the measuring head's electronic system in particular against mechanical, chemical and electrical impact. * Advantages are summed up as follows. * Especially suitable for machine tool rotary tables for combined milling and turning operations. * Measuring speeds of up to 1,160 rev/min. * High amplification factors in control circuit possible. * Reduced requirement for installation space. * Free running bearing centre. * No additional components for measuring system attachment. * No alignment of measuring system. * High measuring accuracy. * Rigid mechanical connection to rotary table. * Resists contamination by greases, oils and emulsions