1. What is the Shaft Diameter Calculation?

The shaft diameter calculation determines the minimum diameter required for a motor shaft to safely transmit torque without exceeding the allowable shear stress of the material.

2. How Does the Calculator Work?

The calculator uses the shaft diameter formula:

Where:

• \( \tau \) — Applied torque (Nm)
• \( \sigma \) — Allowable shear stress (Pa)
• \( \pi \) — Mathematical constant pi (~3.1416)

Explanation: The equation calculates the minimum diameter that can withstand the applied torque while keeping the shear stress below the material's allowable limit.

3. Importance of Shaft Diameter Calculation

Details: Proper shaft sizing is crucial for motor performance and safety. An undersized shaft may fail, while an oversized shaft adds unnecessary weight and cost.

4. Using the Calculator

Tips: Enter torque in Newton-meters (Nm) and allowable stress in Pascals (Pa). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is typical allowable stress for steel shafts?
A: For carbon steel, typical allowable shear stress ranges from 40-55 MPa (40-55 × 10⁶ Pa).

Q2: Does this account for fatigue or shock loads?
A: No, this is for static torsional loading only. Fatigue and shock require additional safety factors.

Q3: What about hollow shafts?
A: This calculator is for solid shafts. Hollow shafts require a different formula accounting for inner and outer diameters.

Q4: How does keyway affect shaft strength?
A: Keyways reduce shaft strength by creating stress concentrations. Typically a 25% reduction factor is applied.

Q5: What units should I use?
A: Use consistent SI units: torque in Nm, stress in Pa, result will be in meters.