Diameter Of Crank Pin Of Centre Crankshaft For Max Torque Calculator

Formula Used:

\[ d_c = \left( \frac{16}{\pi \cdot \tau} \cdot \sqrt{(R_{v1} \cdot b_1)^2 + (R_{h1} \cdot r)^2} \right)^{1/3} \]

Shear Stress in Central Plane of Crank Pin (τ):

Vertical Reaction at Bearing 1 due to Radial Force (R_v1):

Centre Crankshaft Bearing1 Gap from CrankPinCentre (b₁):

Horizontal Force at Bearing1 by Tangential Force (R_h1):

Distance Between Crankpin and Crankshaft (r):

Diameter of Crank Pin (d_c):

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1. What is the Diameter of Crank Pin Calculation?

The diameter of crank pin calculation determines the appropriate size of the crank pin in a centre crankshaft under maximum torque conditions. This ensures the crank pin can withstand the shear stresses generated by the combined radial and tangential forces acting on it.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ d_c = \left( \frac{16}{\pi \cdot \tau} \cdot \sqrt{(R_{v1} \cdot b_1)^2 + (R_{h1} \cdot r)^2} \right)^{1/3} \]

Where:

\( d_c \) — Diameter of crank pin (m)
\( \tau \) — Shear stress in central plane of crank pin (Pa)
\( R_{v1} \) — Vertical reaction at bearing 1 due to radial force (N)
\( b_1 \) — Centre crankshaft bearing1 gap from crank pin centre (m)
\( R_{h1} \) — Horizontal force at bearing1 by tangential force (N)
\( r \) — Distance between crankpin and crankshaft (m)
\( \pi \) — Archimedes' constant (approximately 3.1416)

Explanation: This formula calculates the minimum required diameter of the crank pin to safely withstand the combined shear stresses from both vertical and horizontal force components.

3. Importance of Crank Pin Diameter Calculation

Details: Proper crank pin sizing is crucial for crankshaft durability, preventing mechanical failure, ensuring optimal engine performance, and maintaining safety standards in internal combustion engines and other machinery.

4. Using the Calculator

Tips: Enter all values in appropriate SI units. Ensure shear stress value represents the maximum allowable shear stress for the material. All distance measurements should be in meters, forces in newtons, and stress in pascals.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 16/π factor in the formula?
A: The 16/π factor comes from the torsion formula for circular cross-sections, which relates polar moment of inertia to diameter for solid circular shafts.

Q2: How does this calculation differ for different materials?
A: Different materials have different allowable shear stress values (τ). The calculation uses the specific shear stress limit for the material being used.

Q3: What safety factors should be considered?
A: Engineering practice typically applies safety factors to the calculated diameter, usually ranging from 1.5 to 3.0 depending on the application and material properties.

Q4: Can this formula be used for other types of crankshafts?
A: This specific formula is designed for centre crankshafts under maximum torque conditions. Other crankshaft configurations may require different calculations.

Q5: What are typical values for crank pin diameters in automotive applications?
A: Crank pin diameters typically range from 40-80mm in passenger vehicles and can be significantly larger in heavy-duty and industrial applications.