Viscous clutch

A viscous clutch, comprising:

• a fan housing (100) including a main body (110) and a cover (120), the main body (110) including a fluid storage chamber (S) formed in a middle portion thereof and a fluid outlet (112) and a fluid return hole (114) formed in a side wall of the fluid storage chamber (S), the cover (120) including a concave fluid operating chamber (D) formed in a middle portion thereof, the main body (110) laid over the cover (120) to cover an opening of the fluid operating chamber (D);
• a driving shaft (200) extending in an upper or lower direction thereof and mounted to pass through a bottom plate of the main body (110);
• a rotor (300) fastened to a lower end of the driving shaft (200) to be able to rotate in the fluid operating chamber (D);
• a rotating assembly (400) integrally coupled with the main body (110) to cover the opening of the fluid storage chamber (S);
• a coil core (500) seated on an upper surface of the rotating assembly (400) to create an electromagnetic force when an electric current is applied to the coil core (500) from an outside;
• and
• a valve assembly (600) including a switch valve (610) provided to be able to ascend or descend inside the fluid storage chamber (5) and, when descending, closing a fluid outlet (112) formed in a side wall of the fluid storage chamber (S), an elastic means (620) including a side coupled with the main body (110) and an opposite side coupled with the switch valve (610) to apply a downward elastic force to the switch valve (610), and a magnetic plate (630) fastened to an upper surface of the elastic means (620) and, when an electromagnetic force is created from the coil core (500), pulled towards the coil core (500), wherein the valve assembly (600) opens the fluid outlet (112) when an electric current is applied to the coil core (500) and closes the fluid outlet (112) when the application of the electric current to the coil core (500) is released.