Rear swing arm of motor-bike with tapered rectangular pipe member and method of manufacturing tapered rectangular pipe for vehicle body

摘要

A method for manufacturing a tapered rectangular pipe for a vehicle comprising the steps of forming the tapered rectangular pipe into the rectangular raw pipe by an extrusion forming under any optional irregular thickness condition in a first step. Then the rectangular raw pipe is reduced to form a tapered part to make a tapered, irregular thickness, rectangular pipe member in a second step.