HOLLOW DRIVE SHAFT AND MANUFACTURING METHOD THEREOF

摘要

Providing a hollow driving shaft which is capable of making the strength for the entire length uniform by distributing the load focused on a vulnerable part which can be generated by cross-sectional thickness and the difference of outer diameter is the purpose of the present invention. For the purpose, a hollow driving shaft of the present invention includes: one or more small hollow diameter unit; and a large hollow diameter unit which is formed adjacent to the small hollow diameter unit and has a diameter greater than the small hollow diameter unit. The cross-sectional thickness of the large hollow diameter unit is smaller than the cross-sectional thickness of the small hollow diameter unit, and a first cross section range which has a cross-sectional thickness of 35% to 60% of the large hollow diameter unit from the outer surface of the large hollow diameter unit is carburized to have the same or more than HRC 55 strength.