How rotary dampers provide damping effects

While rotary damper is used, we wonder how rotary damper works?

1. Gear dampers
Due to the invisible braking effect of the viscous grease on the rotating body, the viscous grease in the body produces a damping force on the movement of the moving parts.
The size of the torque is determined by the viscosity of the viscous grease and the oil contact surface.

2.Shaft dampers
The resistance of the damping oil multiplied by the area of the blade produces a torque.
The torque generates  when the shaft rotates. It is determined by the viscosity of the grease, the pressure area of the blade and the gap between the body and the blade.