| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to ensure the rigidity and strength of a vehicle body frame appropriate for a portion of the vehicle body frame.SOLUTION: Main frames 17 are a pair of frames extending from a head pipe 16 rearward with a downhill gradient, gusset frames 20 connected to the main frames 17 are provided in end portions of down frames 19, respectively, seat frames 21 extend rearward from positions in rear of front ends 79b of the gusset frames 20 with an uphill gradient with respect to the gradient of the respective main frames 17, each of the main frames 17 is in an elliptical shape with its longitudinal direction in a vertical direction between the head pipe 16 and a weld bead 79 between the gusset frame 20 and the main frame 17, and a cross-sectional shape of each main frame 17 changes at least in a portion at and the rear of the weld bead 79. |
