Waterpump

摘要

An electrically driven waterpump includes a rotor having impellers for feeding fluid. The rotor is housed in a housing. The rotor includes: a working section located in the fluid and contacting the fluid in a main passage of the fluid stirred by the impellers; and a non-working section located in the fluid and apart from the main passage of the fluid. Water repellency is applied to at least either one of an outer surface of the non-working section or a plane of the housing confronting the outer surface of the non-working section with the fluid interposed, so that shear stress of the fluid is reduced, and pump efficiency is improved.