• A new calculation model for hydro-viscous clutch (HVC) torque and bearing capacity is proposed, replacing the fixed contact area ratio with a discrete micro-ring area ratio (DMAR) integration method to account for radial groove distribution.
• A 32-degree-of-freedom dynamic model of the HVC in a fan drive system is established, enabling prediction of dynamic responses during speed regulation and revealing oscillation phenomena at the engagement steady-state boundary.
• The proposed model accurately predicts axial engagement force and speed regulation curves, validated by experimental data, demonstrating its effectiveness for engineering design.
• The study establishes a numerical relationship between friction plate structure parameters, mechanical properties, and speed regulation performance, providing a theoretical basis for optimizing friction plate design and step-less speed regulation.