Gear Train Designer
Explore an ideal, fixed-axis, parallel-shaft spur-gear train. Enter each gear's teeth, module, axial plane and shaft-center coordinates, then declare actual mesh pairs. Gears sharing a shaft rotate together; external meshes reverse direction and an external–internal mesh keeps direction. The kinematic result assumes ideal rigid engagement and remains conditional if entered center positions disagree with pitch-circle geometry. This is a layout experiment, not a manufactured tooth-profile or strength check.
Key features
- Build 2–8 external/internal spur gears on up to five axial planes and declare 1–12 meshes
- Propagate signed speeds through meshes and compound same-shaft connections; reject contradictory loops
- Calculate pitch diameter d = mz and theoretical external/internal center distances
- Compare entered center coordinates with theoretical pitch-circle contact and list undeclared same-plane contact candidates
- Flag small internal-ring tooth differences for trochoidal interference review
- Export a pitch-circle layout SVG, gear speeds CSV or full analysis JSON
How to use
- Load the compound or internal-ring example, then enter integer tooth counts, module in millimeters, external/internal form, shaft IDs, axial planes and x/y shaft centers.
- Place gears rigidly on a shared shaft by using the same shaft ID and coordinates but different axial planes. Declare each meshing pair on the same plane.
- Select the driver gear and signed RPM. Analyze to propagate speed through all connected gears and compare each pair's actual and theoretical center distance.
- Review every candidate and the limitations; confirm tooth form, backlash, clearances, strength and manufacturability independently before building hardware.
Use cases
- Check that a two-stage compound train gives a signed one-sixth output speed
- Compare an internal ring mesh with an external pair at the same module
- Find a center-position typo before sketching a fixed-axis layout
- Identify an undeclared near-contact on one axial plane
Frequently asked questions
Why can a speed be shown when the center position is wrong?
The tooth-count ratio is a conditional ideal kinematic relationship. A center-distance mismatch is listed as a warning; the tool does not assert that those parts will mesh in the entered layout.
How are internal gears treated?
Exactly one gear in an internal mesh is a ring. The pair has the same rotation direction, its theoretical center distance is half the pitch-diameter difference, and ring teeth must exceed pinion teeth. Every internal pair still needs tooth-profile interference review.
Does a shared shaft multiply the ratio?
No. Distinct gears on the same shaft have identical RPM. A compound train gets its total ratio by multiplying only the tooth-count factors across its declared meshes.
Does no warning mean this gear train can be manufactured?
No. This tool checks only an ideal pitch-circle layout and a few candidates. It does not calculate involute contact, profile shift, backlash, load capacity, bearing support, face width, interference through the full rotation or manufacturing tolerances.
Are my gear definitions uploaded?
No. Analysis runs in this browser tab. Files are created only when you choose a download.
Privacy
Definitions and computed results stay in this browser tab; there is no automatic save or app-server upload.
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