Mclennan Servo Supplies has launched a long travel belt drive system that offers higher dynamic performance, increased accuracy capability and much improved repeatability than conventional belt driven linear positioners. The ServoBelt from USA based servo-mechanics experts Bell-Everman uses a patent-pending design based on two steel reinforced polyurethane timing belts that are meshed and guided through a servo driven toothed roller and idler system held within a carriage supported on linear motion guide bearings and Bosch 45 series T-slot extruded profile .
As the active belting under tension is effectively restricted to less than 75 mm regardless of the travel range, a much increased and uniform stiffness is possible when compared to conventional belt drive systems. This means that servo tuning can have much higher gain factors and superior settling times, allowing significant dynamic performance increase throughout the travel range or the ability to use smaller power motors to achieve the same results. The design also considerably improves both positional accuracy and repeatability specifications for belt driven systems – particularly for longer travel applications.
The standard ServoBelt covers travel ranges from 340 mm to 6040 mm in 60 mm increments and has an out-of-the-box bi-directional accuracy to ±60 microns, unidirectional repeatability of ±10 microns, acceleration to 4 g and speeds to 5 m/sec. In short, the range offers belt drive levels of overall cost, with screw drive dynamic response and close to linear motor speed performance.
The adaptable ServoBelt may be configured for single axes or for multi-axis Cartesian robot systems complete with energy chain cable management if required. The carriage has NEMA 23 and 34 frame sized servo motor mountings with a choice of five motor power ratings available with 16000 and 20000 line rotary encoders.
A wide range of standard and wrap-around rail options are available with single or dual linear motion guide bearings. ServoBelt technical data, available from Mclennan, includes motor sizing for peak axial thrust up to 889 N and load ratings for pitch, yaw, roll and shear type offset loads; and for normal loads with moving mass up to 5.35 kg.
The design can also accommodate multiple moving carriages on the same axis for increased versatility or fit multiple motors to the same carriage for increased thrust. Carriages can move or be held fixed with moving rails - allowing a host of design possibilities for large format handling and assembly systems in packaging, processing and manufacturing equipment.
The low maintenance ServoBelt system is lubricated for life with stainless steel hardware for maximum durability. Options include infinitely adjustable limit sensors and performance enhancement can yield an axial repeatability of just 2 microns with a 1 micron linear encoder option, and higher speeds are available on request.
Mclennan are able to assist with design and commissioning for complete systems and can supply ancilliary equipment to complement the installation of the ServoBelt system.