Propeller fan
Provided is a propeller fan that can prevent deformation of the propeller fan while maintaining the basic performance thereof, such as the air blowing performance, efficiency, and noise performance. In a plastic propeller fan including a hub and a plurality of blades integrally molded in a radial pattern on the outer circumference of the hub, assuming that the radial size of each blade from the base to the outer peripheral edge is 100, a ring member that joins the plurality of blades together is provided at a dimension position of 5 to 45 from the outer peripheral edge.
1. A plastic propeller fan including a hub and a plurality of blades integrally molded in a radial pattern on the outer circumference of the hub, the propeller fan comprising:
a ring member that joins the plurality of blades together, wherein:
assuming that the radial size of each blade from the base to the outer peripheral edge is 100, the ring member is provided at a dimension position of 5 to 45 from the outer peripheral edge;
the ring member is in the form of a cylinder having a fixed width in the axial direction; and
the cylindrical ring member is integrally molded with the blades by injection molding; a molding die provided with parting lines between the adjacent blades; a draft angle toward an air outflow end is provided at a positive pressure surface side, with the blades therebetween, and a draft angle toward an air inflow end is provided at a negative pressure surface side; wherein the ring member having a pre-adjusted wall thickness and the draft angle provided at the inner circumferential surface side to eliminate level differences formed on the ring member due to the draft angles at the air inflow end; and the level differences, corresponding to the amount of the pre-adjusted wall thickness are concentrated at the inner circumferential surface side of the ring member at the air outflow end.
2. The propeller fan according to claim 1 , wherein the draft angle at the inner circumferential surface side of the cylindrical ring member is set larger than the draft angle at the outer circumferential surface side of the cylindrical ring member.
3. The propeller fan according to claim 1 , wherein the ring member is provided at positions passing through crests of serrations provided at the trailing edges of the blades.
4. The propeller fan according to claim 1 , wherein, in addition to the ring member provided at the dimension position, a ring member is provided concentrically at at least one location on the inner circumference side thereof.