Patent ID: 7481711

Claim:
A constant velocity joint structure comprising: a shaft having a first end, a second end, and an annular retaining ring groove formed at said first end, wherein a step part is formed on an axial first-end side surface of said retaining ring groove, said step part protruding from said axial first-end side surface into said retaining ring groove; an inner joint member configured to receive and engage said shaft, said inner joint member defining an insertion hole having an inner surface; and a retaining ring positioned in said retaining ring groove, said retaining ring being radially expandable and contractible elastically, wherein said shaft, said inner joint member, and said retaining ring are shaped and arranged such that when said shaft is engaged with said insertion hole and an axial force is applied to said shaft, said retaining ring contacts and engages with said step part and said inner surface of said insertion hole to thereby prevent said shaft from becoming disengaged from said inner joint member and moving axially with respect to said inner joint member.