For a worm with s starts driving a wheel with N teeth, the ideal reduction ratio is N/s and output revolutions per input revolution are s/N. The selected shaft crossing angle describes layout only; it does not establish compatible tooth geometry.
Skew Worm and Wheel · Selected Ratio Reference
Explore exact ideal worm/wheel count ratios with a connected illustrative crossed-axis topology.
Equation Used
- One worm revolution advances the wheel by the selected number of starts.
- Wheel tooth and worm-start counts are positive integers.
- Crossing angle is a shaft-layout descriptor only.
- Lead/helix compatibility, module, contact, losses, strength and ratings are excluded.
The selected crossing angle controls the displayed shaft layout; all pitch and tooth dimensions are illustrative.
Connected crossed-axis topology
The visual shows a finite worm shaft crossing a wheel at the selected projected angle and meeting at one highlighted illustrative contact region. Worm lead, wheel helix, module, pitch diameters and tooth profiles are not solved.
What the calculator determines
Select wheel teeth, worm starts and shaft crossing angle. The calculator reports exact ideal count ratio, output turns per input turn, output speed percentage and deviation from a right-angle layout.
Ideal count ratio
ratio = N/s; output/input = s/N; output speed percent = 100s/N; skew from 90° = |A − 90°|.
Selected-input arithmetic
For 50 teeth and one start, the ideal reduction is 50:1 and the output turns 0.02 revolution per input revolution.
Ratio and topology only
The model excludes compatible helix and lead angles, normal module, pitch diameters, center distance, tooth contact, interference, efficiency, friction, lubrication, self-locking, forces, stress and ratings.
Questions
Does crossing angle change the count ratio?
No.
Does the drawing prove the selected gears can be manufactured and meshed?
No; its dimensions are illustrative.
References & Further Reading
- Wikipedia contributors. Worm drive. Wikipedia
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