Gearboxes
Gear Quality
Gear quality specifies the accuracy class of a gear per DIN 3961/3962 or ISO 1328. The lower the class number, the more accurate the gear — and the higher the manufacturing costs. It affects running smoothness, noise, contact pattern, and service life.
Quality Classes: Properties and Applications
| Quality class | Property | Typical application |
|---|---|---|
| Q 3–5 | Very high accuracy (ground) | Precision gearboxes, metrology, aerospace |
| Q 5–7 | High accuracy (ground/honed) | Machine tools, robotics, industrial gearboxes |
| Q 8 | Medium accuracy (milled/shaped) | General mechanical engineering, standard spur gears |
| Q 9–12 | Coarse accuracy | Slow-running drives, castings, simple kinematics |
Practical Note
At TEA, spur gears are supplied as standard in quality 8f24 (medium accuracy, tooth thickness tolerance f, deviation range 24). Ground qualities Q 5–7 are available on request and recommended for applications requiring high running smoothness, low noise, or precise positioning. The quality class should be selected to match the application: an unnecessarily high class drives up costs, while too low a class shortens service life and increases noise.
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