Patent WO-2013012100-A2 (WO)
Title: Manufacturing method for grip member for insertion tube in heat exchanger, manufacturing method for heat exchanger using said grip member, and air conditioner and/or outdoor unit having said heat exchanger
Inventor: TOKURA KENJI
IPC: F28F1/32
Filed: 2012-07-20
Abstract: The present invention provides a manufacturing method for a grip member having a grip member guide tube fitted therearound, which enables the manufacture of a heat exchanger in which the entire length of the insertion tubes remains approximately the same as before tube expansion and in which the tubes are expanded to be formed integrally with the radiator fins, when manufacturing a miniaturized heat exchanger having grip members that each have a grip member guide tube fitted therearound, wherein the intervals (pitch) between grip members are minimized while avoiding bringing adjacent grip member guide tubes into contact with each other, or when manufacturing a miniaturized heat exchanger in which not only the interval between each variety of insertion tube having a different pipe diameter but also the interval between insertion tubes has been reduced, even when significantly reducing, due to energy-saving and cost reduction, not only the interval between straight tubes and hairpin tubes inserted in the radiator fins of a heat exchanger or the interval between each straight tube and each hairpin tube inserted in a staggered configuration in the radiator fins, but also the interval between each straight tube and each hairpin tube when said tubes are inserted in the radiator fins in rows of 3, 4, etc. A grip member (3) having a plurality of tube-contacting parts (3f) provided with protruding members (3e) that protrude toward the axial center of the grip member (3) is manufactured according to a method characterized by: a step wherein, in the grip member (3) which can be fitted by a mandrel (2) for tube expansion, of which one end is positioned at the tube opening (7b) of a tube (7), and which has a predetermined total length, the inner part of the grip member (3) is cut at a predetermined depth in the direction of said end from the other end to form, in the vicinity of one end of the inner part of the grip member (3), a bulging section (3z) that bulges toward the axial center of the grip member (3) and that forms an inner diameter smaller than the inner diameter of the cut grip member (3); a step wherein, after the bulging section (3z) has been formed, a plurality of tube-contacting parts (3f) that are capable of radially expanding and contracting are formed in directions perpendicular to the longitudinal direction of the tube (7) in the grip member (3), and by forming a plurality of slit gaps (3a) having a predetermined width (3u) at a predetermined length along the longitudinal direction of the grip member (3) from one end side to the other end side, the bulging section (3z) is divided into the number of the slit gaps (3a) via the plurality of slit gaps (3a), and a plurality of tube-contacting parts (3f) are formed provided with protruding members (3e) that protrude toward the axial center of the grip member (3); and a step wherein, by enlarging the predetermined width (3u) to have an enlarged width (3x) that gradually expands outward from the predetermined positions of each of the slit gaps (3a) toward the direction of the tube opening (7b) of the tube (7), the degree of inclination of inclined surfaces (3b), provided to the outside surfaces of each tube-contacting part (3f) and inclining in a direction expanding toward the tube opening (7b) of the opposing tube (7), is formed to be larger than the degree of inclination of the inclined surfaces (3b) at the time the slit gaps (3a) are formed.