With its extensive portfolio of bearing and torque motor series, automotive and industrial supplier Schaeffler has held an outstanding position in the market for driven rotary axes and rotary tables for many years.
The finely graduated and flexibly combinable portfolio opens up the possibility for manufacturers to develop rotary tables and rotary axles with their own USPs with little effort. Up to now, Schaeffler has offered the absolute Amosin angle measuring system as an option for rotary axes. The new, incremental Amosin angle measuring system closes a remaining gap for applications where an absolute angle measuring system is not absolutely necessary or cannot be used.
Bearing-integrated solution with many advantages
The measuring standard of the Amosin angle measuring systems is mounted on the bearing inner ring and the measuring head is fixed to the stationary bearing outer ring. This means that no design effort is required from the customer when adapting the measuring system to the surrounding structure. The dimensional scale on the bearing inner ring guarantees the best possible concentricity and at the same time the lowest possible tilting of the dimensional scale under mechanical load of the axle. This bearing-integrated solution offers the highest possible measuring accuracy. With other measuring systems outside the bearing plane, the tilting of the axis has a negative influence on the measuring result or must be compensated for at great expense.
The complete integration of the Amosin measuring system into the rotary table bearing also makes it possible to dispense with an adjustment of the air gap between the measuring scale and the measuring head. The manufacturing tolerances are adjusted accordingly. The measuring system is insensitive to dirt, especially to lubricants, and (relatively) insensitive to magnetic fields of direct drives.
Reliable data transmission with combined axes
The incremental angle measuring system was equipped with the classic, analogue 1Vpp interface. This makes it predestined for applications in which the position signal must be transmitted via another rotary axis by means of a slip ring. The advantage here is that the analogue voltage of the sinusoidal, incremental output signals also enables reliable transmission via slip rings and thus operationally safe axes.
Alternative to the absolute angle measuring system
The incremental system has distance-coded reference marks. When the control is switched on, a reference search must be made, but only until the two reference marks are crossed. Then the absolute angular position is known and machining can begin. In practice, this often has no disadvantage if the reference search run is carried out during a grease distribution run, for example.
Symbiosis of bearing arrangement and measuring system
Schaeffler equips its YRTC series rotary axle bearings with the incremental Amosin angular measuring system. The YRTCMI bearings (MI= incremental measuring system) are axial/radial bearings with particularly high rigidity and low, uniform frictional torques. They also have excellent axial and radial runout accuracies. With this combination of properties, the YRTCMI bearings are particularly suitable, for example, for use in hobbing machines and in highly loaded positioning and swivel axes for ultra-precision machining.