Patent ID: 7677346

Claim:
A frame structure of a motorcycle comprising: a head pipe disposed in a front side of a vehicle frame; left and right main pipes extending from the head pipe toward a rear side of the vehicle frame and welded to the head pipe; and a down tube extending from the head pipe toward the rear side and welded to the head pipe; wherein the head pipe includes: a head pipe main body supporting a steering shaft; a main pipe connection portion disposed in a rear upper portion of the head pipe, the main pipe connection portion to which a front ends of the left and right main pipes are welded; and a down tube connection portion disposed in a rear lower portion of the head pipe; wherein the head pipe main body, the main pipe connection portion and the down tube connection portion are integrally formed with one another by a casting or a forging; wherein the down tube connection portion includes: an extension connection portion extending from the head pipe main body in a extending direction of the down tube; and a welding connection portion formed at a rear end portion of the extension connection portion, the welding connection portion to which a front end of the down tube is welded; wherein the extension connection portion includes: a solid portion which is formed in a position close to the head pipe main body; and a down tube supporting portion which extends from the solid portion in the extending direction of the down tube so as to support the down tube; wherein a dimension of the down tube supporting portion in a vehicle width direction is substantially the same as that of the head pipe; and wherein the solid portion is formed with concave portions so that a dimension of the solid portion in the vehicle width direction is smaller than that of the down tube supporting portion.