HZPT
Engineering Guide

Gearbox Selection: Ratio, Torque, Duty, and Interfaces

Ratio is only the first decision

A gearbox is selected around the complete operating condition. Define input speed, required output speed, continuous and peak torque, start frequency, reversal, shock, and operating hours. Then confirm mounting, shaft or flange interfaces, radial and axial loads, lubrication position, ambient temperature, contamination, and access for service.

  • Provide the motor or prime mover data.
  • Describe the driven machine and any jam or overload event.
  • Confirm whether backdriving, holding, or braking is part of the function.

Freeze the mechanical envelope

Use a dimensional drawing whenever the gearbox must replace an existing unit. Record foot and flange dimensions, shaft diameter and length, key or spline, hollow-bore details, torque arm position, and available installation space. Rotation direction should be stated from a defined viewing direction.

Performance Input speed, output speed, continuous torque, peak torque, starts, and duty
Interfaces Motor, input, output, feet, flange, hollow shaft, brake, and accessories
Environment Temperature, dust, moisture, washdown, corrosion, altitude, and cooling

Compare gearbox families

Worm, planetary, helical, bevel, and agricultural gearboxes solve different layout and duty problems. Choose the family after the duty and interfaces are known rather than selecting from appearance alone.

  • Right-angle or coaxial shaft arrangement
  • Compactness, thermal duty, and torque density
  • Mounting, output, backdriving, and maintenance requirements

Explore gearbox and reducer enquiries or use the full technical checklist.