US Patent 11707798 Method for manufacturing liquid-cooled jacket

A liquid cooling jacket is produced by forming a first butted portion where a step side face of a peripheral wall portion and an outer peripheral side face of a sealing body butt each other and a third butted portion where a step side face of a support pillar portion and a hole wall of the hole portion of the sealing body portion butt each other with a gap, and friction-stirring by inserting a tip side pin and a base side pin of a primary joining rotary tool that is rotating into the sealing body and moving the primary joining rotary tool along the third butted portion with an outer circumferential face of the tip side pin being kept off the step side face while having a second aluminum alloy of the sealing body flow into the gap.