Variable-stroke confinement space cold bending device and method

The invention relates to a variable-stroke confinement space cold bending device and method. The variable-stroke confinement space cold bending device and method are particularly used for a pipeline externally coated with a heat insulation layer and PU foam/PUR rigid foam. The device comprises a bending machine body, a bending induction mechanism, a rolling deviation rectifying mechanism, a walking stepping mechanism and a bending keeping mechanism, and the variable-stroke confinement space cold bending machine can achieve the functions of bending induction, coaxial keeping, stepping walking, bending keeping and the like in the pipeline bending process; the hydraulic pressure required by bending can be determined according to different specifications of pipelines to be bent, different jacking strokes can be realized by selecting different hydraulic pressures for pipelines of the same specification, the stroke range is large, the strokes are variable, and further, the processing requirements of pipeline bendin