Abstract: According to the present invention, in a heating apparatus having a viscous heater using viscous fluid for heating cooling water, when an engine rotational speed is lower than a set rotational speed relative to a temperature of viscous fluid, a viscous clutch is turned on to transmit a rotational driving force of the engine to a rotor of the viscous heater. In this way, a shearing force is applied to the viscous fluid in the heat-generating chamber, and the circulating cooling water is heated by generated heat of the viscous fluid to improve the heating capacity. When the engine rotational speed is higher than the set rotational speed relative to a temperature of viscous fluid, a viscous clutch is not turned on. Therefore, the rotational driving force of the engine is not transmitted to the rotor of the viscous heater, so that the shearing force is not applied to the viscous fluid to prevent the oil temperature of the viscous fluid from increasing excessively higher than 200.degree. C.

Abstract: A female screw portion is formed around an axis of a rotor of a step motor to penetrate through the rotor in an axial direction of the rotor. A male screw portion is formed on an outer peripheral surface of a screw shaft so that the screw shaft is screwed into the female screw portion. The screw shaft is inserted in a ring rod, and a connection clip portion is connected to the ring rod. When the rotor rotates, the ring rod reciprocates linearly in the axial direction of the rotor, and vertical fins rock in the axial direction of the rotor.