Size a rack and pinion
Enter the moved mass, speed and acceleration. The calculator works out the tangential force on the pinion, applies the standard load, safety, service-life and load-distribution factors, and shows the smallest RackPro rack and pinion that carry it, with pinion torque and speed for sizing the gearbox. Choose one, download the spec sheet, and send it to us to confirm and price.
The axis
Operating conditions
Load factor KA comes from the drive and load choices (1.00 to 2.25). The service-life factor Fn rises with speed and longer lubrication intervals.
Racks and pinions that fit
Or check a size you have already chosen
Uses the operating conditions in step 2.
How the calculation works
Acceleration a = v / tb. Tangential force per pinion Fu = m·(g·sin θ + μ·g·cos θ + a) + process force, divided by the number of driving pinions (θ = 0° horizontal, 90° vertical). A rack and pinion fits when its load-table force Fu,tab divided by KA · SB · Fn · LKHβ is at least Fu. For a reversing axis the load-table force is first reduced to two thirds, because both tooth flanks are loaded (the same reduction JGMA 401-01 applies). Load-table forces are the rack manufacturer's values for C45 racks, teeth induction hardened to HRC 50–55, with uniform, smooth grease lubrication; module 2 to 8, pinions of 12 to 40 teeth. Every manufacturer calculates these differently, so treat the result as a selection guide. Our engineers confirm every application before we quote.
Need module 10, case-hardened racks, or a load beyond the table? Send us the application. Already know the rack? Use the rack finder or the competitor crossover.
Engineering guides
Practical articles from our engineers on specifying, installing and maintaining these parts.