| 摘要 |
PROBLEM TO BE SOLVED: To achieve cost reduction and improve welding quality by removing an insertion structure which is formed at a connection part with a down frame at a head pipe that is a forged product.SOLUTION: Provided is a main frame fitting part 44 to which a main frame 20 is welded at a head pipe 11 which is made by forging, and integrally provided is a lower part extending part 45 which extends downward from the main frame fitting part 44 and a pipe part 40. A down frame fitting part 50 is provided at the position which is below the lower part extending part 45 and is apart from the main frame fitting part 44 and the pipe part 40 and the upper end part of a down frame 21 is welded here. The down frame fitting part 50 is constituted by a connection part 54 which is in parallel with the pipe part and an extension part 55 which extends from its lower end part to the rear side, and the down frame 21 is welded by contacting only without insertion. By removing an insertion shape, cost reduction is realized and welding quality is improved through being apart from the main frame fitting part 44 and the pipe part 40 which is a part of a heavy load. |
