Spur Gear Pair & Ratio Study
Project Overview
Objective
Develop a dimensioned spur-gear assembly that connects tooth count, module, nominal centre distance, and transmission ratio in an understandable mechanical design study.
Role & Responsibilities
Independent portfolio study focused on geometry, documented inputs, and engineering review.
- Specify tooth counts, module, pressure angle, and bore dimensions.
- Calculate reference diameters and nominal centre distance.
- Construct sampled involute tooth flanks and extrude the gear profiles.
Engineering Features
- Module
- 2 mm
- Teeth
- 20 / 40
- Pressure angle
- 20°
- Reference diameters
- 40 / 80 mm
- Nominal centre distance
- 60 mm
- Ratio
- 2:1
Tools & Software
Outcome
Dimensioned gear-pair assembly and geometry review.
A documented portfolio demonstration. Manufactured or externally validated performance is not claimed.
3D Model
Drag to rotate. Use the viewer controls to inspect the assembly from another angle.
Drawings
Front, side, top, and isometric views of the portfolio geometry. Select the sheet to view it in detail.
| Parameter | Nominal study input |
|---|---|
| Module | 2 mm |
| Teeth | 20 / 40 |
| Pressure angle | 20° |
| Reference diameters | 40 / 80 mm |
| Nominal centre distance | 60 mm |
| Ratio | 2:1 |
Project Gallery
Rendered views of the CAD demonstration. These images show model geometry, rather than photographs of fabricated components.
Source & Engineering Notes
Model Assumptions
Unshifted external spur gears, module 2 mm, 20° pressure angle, and 20/40 teeth. The viewer samples ideal involute flanks; root fillets, manufacturing backlash, and tip relief are not represented.
Design Workflow
- Specify tooth counts, module, pressure angle, and bore dimensions.
- Calculate reference diameters and nominal centre distance.
- Construct sampled involute tooth flanks and extrude the gear profiles.
- Position the gears at the nominal centre distance and inspect engagement.
- Document the geometry and the additional checks required for manufacture.
Engineering Checks
The displayed 40/80 mm pitch diameters, 60 mm centre distance, and 2:1 ratio are geometric calculations. Tooth contact, bending fatigue, lubrication, noise, and manufacturing accuracy have not been validated.
Study Limitations
New 2026 portfolio demonstration. This gear pair is a geometry study and is not released for manufacture.
KHK gear geometry reference