Patent ID: 11965548
Assignee: HONDA MOTOR CO., LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC F  B  C | IPC B  F

Claim 2:
3. The drive shaft according to claim 1, wherein:
the burr includes a first curved portion and a second curved portion, the first curved portion being raised from the first inner wall surface and curved away from the second inner wall surface in the axial direction, the second curved portion being raised from the second inner wall surface and curved away from the first inner wall surface in the axial direction; and
when a virtual line passing through a valley bottom portion, which is formed between the first curved portion and the second curved portion, in a radial direction of the first annular wall and the second annular wall is defined as a virtual centerline, an axial end part of the second annular wall expands toward the first annular wall beyond the virtual centerline by 1 to 30 μm at the friction-welded portion.