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Gear generator: design gears and get the 3D model

Design a gear pair from its tooth numbers and module, see it as a 3D gear model in your browser, and take it into CAD as an exact STEP solid. Straight and spiral bevel gears are sized to ISO 23509 and rated to ISO 10300; spur and helical gears to ISO 21771 and ISO 6336 - in millimetres or inches.

Which gears it generates

A bevel pair turns a drive through an angle - 90° or any other shaft angle; a 1:1 bevel pair is a miter gear pair. Spur and helical pairs connect parallel shafts; the helix angle trades a little axial force for smoother, stronger contact, as the comparison shows with numbers.

From numbers to a 3D gear model

1. Teeth and module. Enter the two tooth numbers and the module - or, in inches, the diametral pitch. The face width, pressure angle, profile shift and backlash follow the standards until you type your own.
2. Checks as you type. Undercut, a pointed tooth tip, a face width past ISO 23509's guide, a bore through the teeth - each is said beside the inputs, most with the value that cures it.
3. Drawings and strength. The axial section and the tooth section are redrawn with every change; with a torque and a speed the pitting and tooth-root safety factors follow.
4. The 3D preview. The pinion and the wheel are built as solids and shown in mesh in the browser. No account is needed.
5. STEP files. The pinion, the wheel and the pair in mesh, in millimetres or inches - the teeth cut the way a generating machine cuts them, not drawn as a picture of a gear.

Gear design: what the numbers decide

The ratio sets the tooth numbers, and the smallest pinion that will not undercut sets how low they can go. The module sets the size of every tooth and with it the load it carries. The face width adds load capacity until the teeth stop sharing it evenly - on a bevel gear ISO 23509's guide is 30 % of the cone distance. Profile shift moves addendum from the wheel to the pinion so a small pinion keeps its tooth root, and backlash keeps the pair from binding. The guides take each step with a worked example:

• How to design a bevel gear pair
• How to design a spur or helical gear pair
• Minimum number of teeth and undercut
• Profile shift
• Bevel gear strength to ISO 10300 and spur gear strength to ISO 6336

The 3D model in your CAD program

The STEP files are exact 3D solids and open in any CAD program that imports STEP - SolidWorks, Inventor, Fusion 360, CATIA, NX, FreeCAD and others - ready for a drawing, an assembly or CAM. The pair file is placed in mesh, so it goes into an assembly as it is. The CAD guide shows how the files are placed and how to mate the pair.

What it does not do

Internal bevel gears and internal spur and helical gears are not generated, the teeth carry no crowning, and there is no loaded tooth contact analysis or scuffing rating. Worm gears and racks are not on the site.

Open the spur & helical designer

Questions