Patent ID: 8656749

Claim:
A tube expanding apparatus for heat exchanger tubes comprising: a pressing plate that has rear end portions of a plurality of mandrels, which have tube expanding billets attached to front end portions thereof, attached thereto and is provided so as to be capable of being raised and lowered in an up-down direction by driving means; a flare platform that is suspended from the pressing plate by rod members and has flare punches attached thereto, the flare punches forming flare portions in opening portions of U-shaped heat exchanger tubes that have been inserted into each of a plurality of insertion holes formed in respective fins of a fin layer in which a plurality of fins are stacked and that protrude from an upper end surface of the fin layer; and a balancer that is provided below the flare platform, contacts the flare platform when the flare platform has been lowered together with the pressing plate that is lowered by driving the driving means, and supports the flare platform at a predetermined position, wherein the driving means of the pressing plate is adjusted so that when the pressing plate is lowered in a state where the flare platform is supported by the balancers at a predetermined position and the tube expanding billets, which carry out primary tube expansion where straight portions of the heat exchanger tubes are expanded to integrate the heat exchanger tubes with the fins, reach boundaries between the straight portions and hairpin portions of the heat exchanger tubes or a vicinity thereof and the primary tube expansion ends, lowering of the pressing plate stops at a position where the pressing plate does not press the flare platform, and wherein the tube expanding apparatus further comprises lowering means that is operable when the lowering of the pressing plate has stopped, to hold the tube expanding billets at positions where the primary tube expansion ended and lower the flare platform to which the flare punches are attached so as to form flare portions in front end portions of the heat exchanger tubes on which the primary tube expansion has ended; wherein the lowering means that lowers the flare platform includes: a support structure that extends upward from the flare platform; an adjustment platform that is movably provided on the support structure and is positionally adjusted at a position where the lowering of the pressing plate stops or a vicinity thereof; and pressing means that is provided on the adjustment platform and presses the pressing plate, the lowering of which has stopped, upward.