Swivelling and driving hub
Front hubs for front-wheel-drive cars need to swivel for steering and to allow up-and-down movement for the suspension as well as having to transmit drive to turn the wheels. Flexible drive shaft joints and ball joints allow all these functions.
The hub and drive shaft rotate inside a cast hub carrier which is turned left or right to steer the car. Driven rear hubs with independent suspension do not need a steering mechanism but sometimes self-steer.