Ultra-High Precision Rack
For rack & pinion applications requiring ultra-precise positioning and repeatability, the system backlash can be eliminated by using two pinions - one to drive the axis and one to "preload" the axis to remove the backlash. Positioning accuracy is maintained during acceleration and deceleration, as well as during changes in direction of travel. We have several different different solutions to achieve a zero-backlash drive system:
Split-Pinions
The simplest zero-backlash drive system utilizes a split-pinion, which consists of two pinion halves and an axial spring pack. The pinion halves mesh with opposite tooth flanks on the same rack, eliminating the backlash.
One pinion half drives the axis while the second pinion half is "preloaded" to remove the backlash. The preload setting of the second pinion half is fully adjustable on the machine by turning the axial spring pack at the end of the pinion shaft.
The split-pinion shafts mount directly into our High-Torque (HT) & High-Performance (HP) Servo-Worm Reducers.
Dual-Pinion Electrical Preload
Another method to remove the backlash at the rack & pinion is to use two motor/reducer assemblies with dual pinions operating on the same rack in a master/slave setup.
One pinion drives the axis (the "master") while the second pinion is "preloaded" to remove the backlash (the "slave"). The preload is created electronically with a special motor controller; these systems can also be set up to drive together during cycle times when backlash is not critical.
Dual-pinion gearboxes using only one motor are also possible, please consult the factory.
Our Automatic Lubrication Systems are highly recommended for use with these drives, providing continuous grease lubrication to the rack & pinion tooth flanks to preserve the quality and lifetime of the gearing.
These drives are perfect for precise positioning applications, such as traveling gantries and columns, milling machines, CNC routers and material feel axis drives. Two reducers/motors can also be used to eliminate the axis backlash by electrical preload.
