Impeller in water pump.

摘要

An impeller (20) in a water pump for circulation of cooling medium in a cooling system of an engine. A shroud (24) has a boss shroud (23) to which the edges of the blade inlets (21) are attached and which is formed in the cylindrical configuration substantially parallel to the rotary shaft (15). Each of the edges (26a) of the blade inlets is shaped so that it is continuousley smooth from a boss shroud surface (24a) at the inlet side thereof and extends upstream in the axial direction, while each of the edges (26b) of the blade inlets at the side of a casing extends substantially perpendicularly to the rotary shaft (15), the edge (26a) of the blade inlet attached to the cylindrical boss (24a) shroud and the edge (26b) of the blade inlet at the casing side being connected therebetween by a smooth arc-like curve projecting convexly upstream. The inlet angle of said blade is set to substantially 0 DEG at the inlet edge (26a) at the boss shroud and to an angle calculated substantially on the basis of the conventional design at the inlet edge (26b) at the casing side. The impeller (20) has the blades (25) each formed by connecting the blade inlet (26) of such configuration to an blade outlet (27) by a smooth curved surface. <IMAGE>