Description
Planetary Gear Sets
A planetary gear set combines a sun gear, multiple planet gears, an internal ring gear, and a carrier. Because several planet meshes can share the transmitted load, the architecture can deliver high torque density in a compact concentric arrangement. Custom gear sets require the full geometry to be treated as one system rather than as four unrelated gears.
Core Components
| Component | Engineering Role |
|---|---|
| Sun gear | Central external gear; commonly the input or reaction member |
| Planet gears | Mesh with sun and ring while rotating on carrier pins |
| Ring gear / annulus | Internal gear surrounding the planets |
| Planet carrier | Locates planet shafts and often serves as the output member |
Geometry Inputs
| Required Input | Typical Detail |
|---|---|
| Tooth counts | Sun, planet, and ring tooth counts |
| Module / DP | Metric module or diametral pitch |
| Pressure angle | Specify the design value |
| Helix angle | Zero for spur or specified for helical gearing |
| Face width | Usable tooth width and shoulder constraints |
| Center distance | Required from assembly geometry |
| Quality target | DIN/ISO/AGMA grade or application tolerance |
| Heat treatment | Material, case depth, hardness, finish grinding |
System Compatibility
Planetary tooth counts are constrained by center distance, meshing relationships, planet spacing, profile shift, and assembly conditions. Replacing one gear without checking the rest of the train can create interference, uneven load sharing, noise, or premature failure.
Drawing Package
For reverse engineering, send the complete assembly, drawings if available, clear tooth photos, bore or spline data, measured outside and root diameters, face widths, and operating torque or power. A sample is valuable when the original drawing is unavailable.
FAQ
Can you quote from tooth count alone?
No. Tooth count is only one part of the geometry. Module or DP, pressure angle, face width, material, heat treatment, bore or spline, and quality target are also required.
Can a ring gear be supplied separately?
Yes, but its tooth geometry and mating sun/planet data should be verified to avoid a mismatch.
Do helical planetary sets need extra information?
Yes. Helix angle, hand, axial-force management, and lead quality become important.
What is the fastest path for a replacement project?
Send the old assembly or drawing plus operating data. That allows dimensional verification and duty review in parallel.
Data Note: Component roles follow Ever-Power public planetary-gear descriptions. Specific custom geometry is defined only from customer drawings, samples, or confirmed engineering data.
Quote A Planetary Gear Set
Share ratio, input speed and power, required output torque, duty cycle, mounting space, shaft or flange interface, environment, quantity, and any drawing or existing gearbox reference. Our engineering team will review the configuration before quotation.
