Preloaded Rack & Pinion Drive Systems

Introduction:

Even high-precision rack & pinions with minimum backlash cannot meet the positioning requirements of ultra-accurate CNC machine tools.  For these requirements, a preloaded rack & pinion drive is needed.

These systems effectively eliminate the backlash between the rack & pinion with the use of two pinions – one to drive the axis and one to preload the axis to eliminate the backlash.

Accurate axis positioning is thus preserved - and is maintained even during the transition period between acceleration/steady state and deceleration, when the rack & pinion flank contact and load reverses direction. 

Preloaded systems consist of a rack, two pinions, and a reducer/motor drive system.

Complete & dedicated solution

REDEX-ANDANTEX offers to machine designers a complete range of standard gearboxes especially dedicated to preloaded rack and pinion axis drives systems.

Integral output pinion insures optimum torsional & radial stiffness Precise geometry for high precision meshing with the rack Felt gear for optimal rack & pinion lubrication Five mounting surfaces & through holes allowing universal mounting

Multiple oil drain, fill & level holes for use in any mounting position Universal motor flange Special seal for protection from chips

Top class quality design and manufacturing

Dedicated to Rack & Pinion application
  Optimized Radial & Torsional stiffness to get the highest natural frequency

Ultra high linear accuracy
  Backlash free, pinion / rack accurate mesh & very low pitch error

High technology planetary gear train
  Based on REDEX ANDANTEX’s differential know how

Smooth operation & low noise level
  High quality hardened and ground gears

Ready to use
  With a rigid, monoblock housing and ground mounting surfaces

Compact
  Weight & space savings

100 % Tested
  Drag torque, vibrations, torsional & radial stiffness).
  Two years warranty - Worldwide support

There are two different types of preloaded rack & pinion drive systems:

A GLOBAL RANGE

TwinDRIVE: Electrical preload Click on images for specs PDF. Electrically preloaded TwinDRIVE units achieve the preload by “electrical braking” one pinion against the other. One pinion is considered as the driving pinion, while the other is braking. This system requires two motors and a special motor controller to handle the preload.

DualDRIVE: Mechanical preload Click on images for specs PDF. Mechanically preloaded DualDRIVE units achieve the preload by torsionally winding one pinion against the other. One pinion is considered fixed and the other spring loaded. This system is driven by only one motor and doesn’t require any special motor controller. The preload is obtained with a REDEX patented preloading system.

Motor controller performance and system stiffness requirements must be analyzed to avoid excitation frequencies. Precise positioning and contouring (i.e. positioning while cutting on a machine tool) can be achieved with this design. Radial pinion deflection is minimized by heavy-duty bearing support. 

For more information about preloaded rack & pinion drive systems, please call us at (800) 713-6170 or e-mail us. Our Sales and Engineering departments are ready to help you with your specific power transmission needs.