To further achieve miniaturization and lightweight by shortening an axial dimension without enlarging the outer diameter of a driving wheel bearing device.
The driving wheel bearing device comprises: a hub 10; a double row roll bearing 20; an outboard side constant velocity joint 30. The contact angle α of outboard side rolling element row 26a of the double row roll bearing 20 is equalized to the contact angle α of the inboard side rolling element row 26b, the pitch circle diameter PCDo of the outboard side rolling element row 26a made larger than the pitch circle diameter PCDi of the inboard side rolling element row 26b, the outboard side constant velocity joint 30 is disposed to the outboard side more than the double row roll bearing 20, and center O of the outboard side constant velocity joint 30 is disposed to the inside of the bearing span of the double row rolling bearing 20. An end cap 48 that is provided with a rubber layer on the outer surface is attached to the outer side opening part of a through-hole 18 of a hub 10, and a boot assembly 40 that comprises a boot body 42 and a boot adapter 44 is attached to the inner side opening part.
Tsuyoshi Kumano
Yoshiyuki Shiraishi