RACK AND PINION DRIVE SYSTEMS FEATURES
Rack and Pinion. What is it?
A rack and pinion drive system is just what it sounds like. There is a rack that is bolted onto the sides of the machines and pinion, or cog/gear, that meshes with the rack. As the pinion turns, the machine moves. Straight racks and helical (angled) racks merge to drive.
What does it do well?
Best known for their rigidity, rack and pinion drives can deliver precise motion over unlimited lengths. They are built to travel the full distance of a machine, no matter the length, without “screw whip” concerns (more on that later). Rack and pinion systems have high up-time and can produce for years with minimal wear and are very favorable in the environment of a fab shop, being virtually impervious to dust and debris.
Helical rack and pinion designs are angled instead of straight, with more teeth in the mesh of the rack. The helical design creates a smooth, low-friction movement and delivers zero backlash with a positional accuracy of ±0,005mm throughout the entire travel distance of the machine. They also excel in accelerating, de-accelerating, and maintaining higher speed processing which is a result of their constant stiffness and exceptional transfer of power, or efficiencies, that are upwards of 97%.
The simplicity in the design of rack and pinion is a huge plus, benefiting end users. They are usually simple bolt-on systems that are easy to replace – not requiring special skills or knowledge.
What are its weaknesses?
Old rack and pinion technology was known for their cons of having higher friction and potential backlash of the pinion. Advances in gear production techniques (milling, grinding, and heat treatment, for example) have dramatically improved the precision and load carrying capacity of rack and pinion drives, to the point that they are a competitive component for any linear-axis drive application.
