VALICALC / MECHANICAL ENGINEERING SUITE / DS10
Define the actual tooth counts and module convention before calculating a spur or helical pair. External shifted pairs use an involute solve; internal pairs expose unshifted reference geometry with separate interference limitations.
Verified mathematical models with explicit assumptions. Component capacity and applicability are shown as separate checks.
Labeled example inputs • SI calculations • Project revision 0 • No account or cloud upload
01 / ENGINEERING INPUTS
02 / CALCULATE → SELECT → RECALCULATE
Normal module
3 mmTransverse module
3 mmNormal pressure angle
20 degTransverse pressure angle
20 degWorking pressure angle
20 degReference center
120 mmActual working center
120 mmActual tooth ratio
3Pinion working pitch diameter
60 mmGear working pitch diameter
180 mmTransverse contact ratio
1.67078Axial overlap ratio
0Total geometric contact ratio
1.67078| Member | Teeth | Reference pitch d (m) | Base d (m) | Tip d (m) | Root d (m) |
|---|---|---|---|---|---|
| Pinion | 20 | 0.06 | 0.056382 | 0.066 | 0.0525 |
| External gear | 60 | 0.18 | 0.169145 | 0.186 | 0.1725 |
External pairs require opposite hands; internal pairs require the same hand. Spur teeth have no helix hand.
Actual integer tooth ratio is recalculated; zero tolerance requires exact equality.
Requires the actual cutter, profile, tip thickness and manufacturing method. Contact ratio alone does not validate interference.
Geometry supplies no gear strength or stock availability approval.
Ideal active involute path and overlap only. Cutter interference and thin tips still require independent checks.
Normal/transverse pressure angles and modules are converted together. All angles are radians internally.
External normal shift uses inv(αwt) = inv(αt) + 2 tan(αn)(xn1+xn2)/(z1+z2). Tip shortening follows the stated KHK full-depth rack convention.
Actual selected tooth counts and shifts drive diameters, working center and contact; no numerical standard table is copied.
External full-depth rack geometry: addendum coefficient 1, dedendum 1.25; KHK tip-shortening convention. Manufacturing backlash, tip thickness, cutter interference, undercut and material capacity are separate, unresolved checks.
Internal gears support zero-shift reference diameters and center only. Internal shifted geometry/contact/cutter clearance remain blocked; matching module is not proof of interference-free operation.
Entered integer teeth/module are actual design candidates, not confirmed stock products. Helix hand is checked only for parallel-axis mating. Normal-system and transverse-system full-depth racks have different tooth heights; converted module/pressure angle preserve pitch geometry, not necessarily tip/root geometry.
With 20 and 60 teeth, normal module 3 mm, zero helix and zero shift, pitch diameters are 60 and 180 mm and center is 120 mm. Changing to a 30° helix increases transverse module and center; selecting teeth recalculates the entire pair.
Parallel-axis full-depth rack reference geometry. External profile shifts use a bounded involute solve and the explicitly stated normal/transverse tip-shortening convention. Internal geometry is unshifted only.
External involute path at stated actual working center. Ideal contact continuity is not an undercut, cutter or strength approval.
KHK Gear Technical Reference, contact ratio §11; independent tangent-path derivation.
Textbook references identify the method context. Historical numerical catalog, material and service-factor tables have not been copied or treated as current product ratings.
Existing component-selection Jobs → · All mechanical worksheets →
No. The worksheet separates mathematical results from criterion-specific checks. Actual motor, belt, gear, shaft, bearing and joint capacity need applicable current source data and engineering review.
The worksheet recalculates the outputs and geometry from the entered actual dimensions or discrete tooth/link count. Dependent checks are reevaluated; previously saved results are not restored as approvals.