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

Claim 0:
1. A drive shaft comprising:
a first annular wall with an annular shape provided at an end part of a hollow tubular body made of a medium carbon steel; and
a second annular wall with an annular shape provided at an end part of a solid stub shaft made of a medium carbon steel, the first and second annular walls being joined together in an axial direction via a friction-welded portion, wherein:
the first annular wall and the second annular wall have outer diameters of 30 to 50 mm and wall thicknesses of 3 to 5 mm;
at the friction-welded portion, a burr is partially raised from a first inner wall surface, which is an inner wall surface of the first annular wall, and from a second inner wall surface, which is an inner wall surface of the second annular wall;
the burr includes
a burr base part, which is a basal end at which the burr is raised from the first inner wall surface,
an orthogonal part, which extends in a direction orthogonal to the first inner wall surface, and
an intermediate curved part, which curves between the burr base part and the orthogonal part;

the burr base part includes
a connection part, which is an end part of the burr base part adjacent to the first inner wall surface and connects the burr base part and the first inner wall surface with each other, and
a slope part, which slopes with respect to the first inner wall surface and extends from the connection part to the intermediate curved part,

a connection radius, which is a radius of curvature of the connection part, is greater than or equal to 0.5 mm;
a base radius, which is a minimum radius of curvature of the intermediate curved part, is greater than or equal to 0.5 mm;
a burr base angle, which is an angle of inclination of the slope part relative to the first inner wall surface, is less than or equal to 40°; and
a burr slope length, which is an axial length of the part between the burr base part and the orthogonal part, is in a range of 0.2 to 5 mm.