Gears and transmission
DIN 3961 Involute Spur Gear (m=1.5, z=15, x=+0.5)
- Bounding box
- 25.3 × 25.4 × 10.0 mm
- Engine
- Precision B-rep
- Parameters
- 8
- Published
- October 8, 2026
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The prompt
Create a precision mechanical CAD model of a 15-tooth external involute spur gear. GEAR STANDARD: - Gear type: External spur gear - Tooth profile: True involute - Standard reference: DIN 3961 / DIN 867 - Pressure angle: 20° - Number of teeth (z): 15 - Module (m): 1.5 mm - Profile shift coefficient (x): +0.5 - Helix angle: 0° (spur gear) - Units: millimeters PRIMARY GEOMETRY: - Reference/pitch diameter: d = 22.50 mm - Outside diameter: da = 27.00 mm - Root diameter: df = 20.25 mm - Base diameter: db ≈ 21.14 mm - Bottom/root clearance: 0.25 × module - Gear thickness: 10 mm - Center bore: 6.00 mm pilot hole TOOTH GEOMETRY: - Generate the tooth flank using a mathematically accurate involute curve generated from the 20° base circle. - Generate exactly one complete tooth profile and circularly pattern it exactly 15 times over 360°. - Maintain exact tooth spacing and angular symmetry. - Include realistic smooth root fillets between adjacent teeth. - Do not approximate the teeth using simple triangles, trapezoids, or polygonal approximations. - Maintain correct addendum, dedendum, tooth thickness, backlash allowance, and profile shift corresponding to x = +0.5. - Avoid tooth interference and malformed root geometry. - Preserve continuous tangent transitions between involute flank, tip, and root fillet. MECHANICAL/CAD REQUIREMENTS: - Gear center exactly at global origin. - Gear axis aligned with Z axis. - Fully closed watertight solid. - No self-intersections. - No duplicate or open faces. - Clean B-rep topology. - All 15 teeth must be identical. - Symmetric geometry around the central axis. - Bore concentric with the gear. - Suitable as a manufacturing/CNC reference model. - Parametric CAD-ready solid geometry. - High geometric precision. OUTPUT: Create a single 3D solid external spur gear. Prefer native parametric CAD geometry. Export-ready for STEP AP214/AP242. Do not create a visual-only mesh. The final model must be a true manufacturable solid with accurately generated involute teeth.
Parameters
| Name | Value | Range |
|---|---|---|
| Module (m) | 1.5 mm | 0.5 – 5 |
| Number of Teeth (z) | 15 teeth | 8 – 60 |
| Face Width | 10 mm | 2 – 40 |
| Center Bore Diameter | 6 mm | 0 – 25 |
| Profile Shift Coefficient (x) | 0.5 x/m | -1 – 1 |
| Pressure Angle | 20 deg | 14.5 – 25 |
| Helix Angle (0 = spur) | 0 deg | 0 – 30 |
| Root Fillet Radius | 0.4 mm | 0 – 1 |
Every value above is a live dimension. Open a model like this in the editor and each one becomes a slider you can drag before exporting.
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