HEAT TRANSFER FIN, FIN-TUBE HEAT EXCHANGER, AND HEAT PUMP DEVICE

摘要

A heat transfer fin (3) includes: a base portion (4) having a flat surface (4a); a cylindrical collar portion (5) extending upwardly from the base portion (4); a flared portion (6) flaring radially outwardly from an entire upper end of the collar portion (5); and a receding portion (7) having an inclined surface extending upwardly from a bottom of the collar portion (5) at an acute angle with respect to a direction toward the upper end of the collar portion (5). The bottom of the collar portion (5) is located at a position not reaching a reference plane when the flat surface (4a) of the base portion (4) is the reference plane.