Double-Wall Pipe, Method Of Manufacturing The Same And Refrigerant Cycle Device Provided With The Same

A method of manufacturing a double-wall pipe including an outer pipe and an inner pipe, the method comprising the steps of:

• forming a groove portion extending in a longitudinal direction on an outer wall of the inner pipe, so as to form thereon a ridge portion defining the groove portion;
• inserting the inner pipe into the outer pipe having an inside diameter greater than an outside diameter of an imaginary cylinder defined by an outer surface of the ridge portion of the inner pipe, after the groove portion is formed;
• and
• bending a part of both the inner pipe and the outer pipe after the inserting step, to form a bend portion in such a manner that the ridge portion contacts an inside surface of the outer pipe by radially squeezing and deforming the outer pipe in the bend portion, thereby the outer pipe squeezes the inner pipe radially to hold and fix the inner pipe therein in the bend portion.