| 摘要 |
PURPOSE:To stop operation of a fan positively when the engine temperature is low and to warm up an engine efficiently, by driving a brake shaft in the axial direction by causing change in the shape of a temperature-sensitive member in response to the engine temperature, and bringing the brake shaft into engagement with a rotatable housig to which the fan is attached. CONSTITUTION:In case that the engine temperature is low, for instance, just after starting of an engine, a coil 35 made of a shape memory alloy is expanded and a brake shaft 31 is moved forward, so that the top 33 of the brake shaft 31 is brought into engagement with a hole 34 formed in a partition plate 7. Therefore, a housing 3 formed integrally with the partition plate 7 is not turned and a cooling fan 5 is stopped. As the engine is warmed up gradually and the temperature of cooling water becomes higher than the critical temperature of the coil 35, it is contracted and the top 33 of the brake shaft 31 comes out of engagement with the hole 34. Resultantly, the housing 3 is set free and the cooling fan 5 begins to turn by a small torque transmitted from a driving shaft 1. Subsequently, when the temperature of cooling water exceeds the work temperature of a bimetal 13, the torque transmitted from the driving shaft is increased, so that the cooling fan 5 is turned at a high speed. |
