To provide a pipe bending machine and method capable of preventing the buckling on an inner side of bending without using tools, such as a core bar and wrinkle prevention, and easily controlling the circumferential length during bending in a longitudinal direction, by suppressing the thickness reduction on an outer side of bending even in performing small R bending of R/D<2.
The pipe bending machine comprises a bending die 1 having a groove part of a shape corresponding to a bending shape, a clamp 2, a pressing die 3 and a pressing means 8. The pressing means 8 pressurizes an intersection of a contact point of the bending die 1 and a pipe P and a straight line L1 obtained by shifting a straight line L0 passing the center O of rotation to a pipe inlet side by a distance δ(≤D) and with the pressing die toward the straight line L1 direction. As a result, the action of the unnecessary bending moment of the inlet side of the bending section to the pipe can be reduced without deforming the bending die body section. Further, the compressive stress is applied to the pipe by making the circumferential length of a portion combined with the groove part and the pressing die 3 shorter than the circumferential length of the pipe, thereby effectively preventing the buckling on the inner side of the bending and the thickness reduction on the outer side of the bending.
HASHIMOTO YUJI
SONOBE OSAMU
SATO AKIO
UENO KOICHI
OKADA MASAO
SAITO KOJI
YOSHIDA HIROHIDE
TOYOTA MOTOR CORP
TAIYO KK
| JPS63189413A | 1988-08-05 | |||
| JPS555180A | 1980-01-16 | |||
| JP2000326013A | 2000-11-28 |
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