Advantages:

1. Lower manufacturing difficulty

Enables production of ultra-large specifications without requiring extra-large tonnage forging presses or ultra-long machining tools. Suitable for low-speed, high-power marine diesel engines and extra-long crankshafts for large generator sets.

2. Better maintenance economy

When a certain crankpin journal suffers wear, cracks, or damage, only the damaged segment needs to be replaced rather than scrapping the entire crankshaft, significantly reducing overhaul costs.

3. Lower requirements for transportation and tooling

Segmented parts are small in volume and light in weight, facilitating transport and machine clamping, while reducing plant equipment investment.

4. More flexible lightweight design

Individual crank segments can be independently hollowed out and optimized for weight reduction, making the overall crankshaft weight easier to control.

Disadvantages:

1. Lower overall stiffness and strength compared to integral design

Segments are fastened by connecting bolts and flanges, with clearances at the joint interfaces. Under alternating torsional loads, micro-slip tends to occur, resulting in poor overall bending and torsional resistance. Not suitable for high-speed engines.

2. Poor dynamic balance, high vibration and noise

Multi-segment assembly accumulates coaxiality errors, leading to large rotational eccentricity. At high speeds, vibration is significant, and dynamic balance correction is difficult.

3. Complex assembly process and larger overall dimensions

Segmented assembly requires precise positioning and stepwise bolt tightening according to specified torque, increasing assembly time. The flange structure also adds to the engine's axial length, making the overall engine structure less compact.