Herringbone Planetary Gear Set

Herringbone Planetary Gear Set render

gears/planetary/herringbone_planetary_gear_set.pyOBJECT_OT_herringbone_planetary_gear_set (object.herringbone_planetary_gear_set, "Herringbone Planetary Gear Set")

Same topology and assembly math as planetary_gear_set.md, same hand-derivation rule as helical_planetary_gear_set.md — read both first. This document only covers what's different: V-shaped teeth on all three members.

Properties

Same as the spur planetary set, plus:

Property Type Default Range Notes
helix_angle_degFloat (°)20.01–45Half-angle of the V, applies to all three members
hand (labeled "Sun Hand")EnumRIGHTRIGHT / LEFTSets the sun's hand; planet/ring derived (R→L→L / L→R→R)
width_mm (labeled "Total Width")Float (mm)14.02–80 (soft)Full face width — each half is width_mm/2, shared by all three members
n_slices (labeled "Slices per Half")Int122–48 (soft)Total slices built per member = 2*n_slices - 1

sun_teeth, planet_teeth, planet_count, module, pressure_angle_deg, ring_wall_mm, pip_gap, outer_segs are identical to the spur set.

What's identical to the other two planetary sets

The tooth-count rule (ring = sun + 2*planet), the assembly condition ((sun+ring) % planet_count == 0, warning-only), the planet orbital-phase formula, the ring's -pi/ring_teeth phase correction, and the hand derivation (sun chosen, planet = opposite, ring = same as planet) are all identical to the spur and helical planetary sets — only the mesh builders differ. If you already understand those two docs, the only new thing here is the V-shaped tooth geometry itself.

Build method

Sun and planet: each built as two mirrored helical halves sharing a mid-slice, same approach as a standalone herringbone gear (herringbone_gear.py) — bottom half twist 0 → peak, top half peak → 0, 2*n_slices - 1 total slices, peak_twist = (width_mm/2) * tan(helix_angle) / pitch_radius (computed per-member using that member's own pitch radius). Ring: solid cylinder minus a herringbone-twisted annulus cutter (same approach as herringbone_annulus_gear.md).

Info box shows normal module, the sun's peak twist in degrees, and total slice count (2*n_slices - 1).

Output

2 + planet_count objects per call: HbPlanetaryRing, HbPlanetarySun, and HbPlanetaryPlanet.001.00N (linked-mesh copies). Success message: "Herringbone planetary: %d/%d/%d teeth (sun/planet/ring), %.1f° helix, %d planets".