BACK FRAME STRUCTURE OF VEHICLE SEAT

摘要

PROBLEM TO BE SOLVED: To provide a structure where increase in weight can be suppressed in a back frame having a structure formed by joining a side frame and an upper frame while joint strength thereof is secured.SOLUTION: A portal back frame is formed by inserting at least part of a second side frame part 33 of a second frame member 30 which is formed by subjecting a first side frame part 31 extending in a longitudinal direction, a second side frame part 33 extending in a longitudinal direction and an upper frame part 32 as one piece of pipe-like member to bending work, into a closed cross-sectional shape part 27 of a first frame member 20 extending in a longitudinal direction and becoming unified.