Cycloidal Shape Designer

Set your geometry, pick how each part will be made, and the tool converts your shop's real accuracy into the backlash of the units you'd actually build. Then one click finds the tooth modification that still meets your target despite those errors.

Geometry & spec

pin-circle Rb mm

pin radius Rr mm

eccentricity E mm

lobes N

rated torque N·m

Advanced (system, durability, thermal — rarely needed; sensible defaults)

disk width mm

bearing clr. µm

output clr. µm

output pins

output PCR mm

output pin r mm

ecc-bearing C N

input speed rpm

temp rise ΔT °C

housing CTE µm/m·K

gear CTE µm/m·K

friction µ

discs (phased)

tool radius mm

adjustable ecc matched assy

output rollers rolling

Manufacturing plan — pick how each part is made; the ±µm numbers are editable if you know your shop better

disk profile ±µm

pins ±µm

pin holes ±µm

eccentric E ±µm

Geometry undercuts — the unmodified tooth can't mesh with all pins. Reduce E or increase Rb.

Optimize for this geometry one click → the optimal curve loaded into the sliders, judged on the backlash of the units you'd actually build

run once to see the design front

non-dominated designs (backlash ↔ stiffness, colour = pressure angle)

Mesh

Worst-case jam — locks if every manufacturing error lands at its tightest

speed

pins / housing disk (your design) tooth under load

Modification δ(θ)=offset + Σ cₖ·cos(kNθ)

offset even removal

c1 tip ↔ root bias

c2 mid-flank (reverse-bow)

c3 flank fine shape

c4 flank fine shape

backlashzero-error ideal, mesh only

as-built backlashMonte-Carlo over your plan · typical–95%

ripplewind-up variation = smoothness

mesh efficiencysliding loss · mesh + output pins · fwd / backdrive

stiffnesssystem: mesh ⊕ output pin-hole (bearings excl.)

More metrics (durability, system, thermal, manufacturability)

system

system lost motionmesh + bearing clr + output pin-hole

loaded teethsharing the rated torque

preload for zero backlashmin interference · no-load stiffness · drag

durability

contact stresspeak Hertz pressure, loaded pin

safety factorvs 1500 MPa contact-fatigue limit

output-pin stressHertz on output pins · safety

bearing lifeeccentric-bearing L10 · mesh + output reaction

sliding / wearpeak slip · PV scuffing-wear index

thermal

thermal driftbacklash at ΔT · housing↔gear CTE mismatch

manufacturability

worst-case marginevery error at its tightest — >0 still assembles

min flank radiustightest concave curvature vs finishing tool

Tooth flank one tooth · modification ×40

unmodified (pure conjugate) modified flank

Clearance across one tooth normal gap vs mesh phase

shipped design uniform your design worst-case error

Export to SolidWorks equation-driven curve · numbers baked in · units mm

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