PIPE EXPANSION DEVICE

Japanese Patent JP2021192919

A

To provide a pipe expansion device capable of stably performing pipe expansion processing even if there is center dislocation of an end of a first pipe or an opening of the end is an elliptical shape when expanding a diameter of the end part of the first pipe to a diameter that allows insertion of a second pipe.SOLUTION: A pipe expansion die 18 includes: a plurality of diameter expansion projection parts 18a projecting in a radial direction so as to have a rotation diameter corresponding to a diameter after expansion of the diameter of an end of a first pipe P1; and a plurality of tapered projection parts 18b projecting in the radial direction such that the rotation diameter continuously decreases to a rotation diameter sufficiently smaller than a diameter of the opening from the plurality of expansion diameter projection parts 18a. Thus, when the expansion pipe die 18 is subjected to diameter expanding processing in which it is threadedly advanced in a rotation center line C1 direction toward the inside of the end of the first pipe P1, stable expansion pipe processing becomes possible without deforming a pipe wall of the end of the first pipe P1 in the rotational center line C1 direction even if the center of the end of the first pipe P1 is dislocated or an opening of the end is not a perfect circle.SELECTED DRAWING: Figure 5

JP2549204

An expansion device

OCHIAI MASAMITSU
YAMADA KEIJI

JP2020099699A

December 23, 2021

June 08, 2020

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DAIA CO LTD

B21D39/20; B21D39/04

Haruyuki Ikeda
Kojiro Ikeda

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