DAC (Double Angular Contact) wheel hub bearings are a common first-generation hub unit design found in modern car wheels.  They integrate two single-row angular contact bearings, pre-lubricated and sealed, into a single unit, simplifying installation. They primarily handle radial and axial loads, ensuring smooth wheel rotation. They are constructed using ball bearings or tapered roller bearings, connecting the outer ring of the bearing to the wheel, providing precise guidance and reducing friction.

Key Features:

Integrated Design: Composed of two single-row bearings with an integrated outer ring, pre-filled with grease and sealed, eliminating the need for user adjustment of bearing clearance.

Load Capacity: Capable of simultaneously handling radial loads (up, down, left, and right) and axial loads (front and back) from all directions.

Simplified Installation: As a pre-assembled unit, installation is more convenient, reducing the complexity of on-site operations.

Type Differentiation: DAC usually refers to models using ball bearings, while those using tapered roller bearings may be referred to as DU type (although many are now also called DAC series).

Importance:

It is the connecting bridge between the wheel and the axle, allowing the wheel to rotate freely.

Failure can affect vehicle handling, lead to uneven tire wear, and even cause wheel detachment, which is extremely dangerous.

Applications:

Widely used in various passenger cars, it is an important support for automotive transmission and steering systems.