essieu

Essieu is the French term for axle, the rigid member that forms the connection between wheels and a vehicle or machine. The essieu supports the vehicle weight, transmits torque from the drivetrain to the wheels (in drive axles), and provides mounting points for bearings, suspension components, and, in some configurations, brakes.

In road vehicles, the term covers both rigid (live) axles and elements of independent suspension. A rigid or live axle connects two wheels to a single shaft, which may be solid or hollow and which rotates with the wheels. Independent suspension uses separate mounting points and linkages for each wheel, allowing vertical motion without a single rigid connection across both sides; the term essieu can still refer to the axle shafts and mounting points in such setups. Front and rear axles may be designated as essieu avant or essieu arrière, and drive axles as essieu moteur in cases where they transmit power.

In railways, the essieu describes the axle on which a wheelset is mounted; typically two wheels are rigidly fixed to one axle. Wheelsets may be part of a bogie, where two or more axles share a common frame. In locomotives and other powered rail vehicles, essieux moteurs denote drive axles, while essieux porteurs refer to non-driving, weight-bearing axles.

Construction and maintenance: Essieux are commonly made of steel and designed to resist bending and torsion. They may be solid or hollow to balance strength and weight. Bearings, seals, and lubrication reduce wear and heat. Regular inspection for cracks, corrosion, and bearing wear is essential, as axle failure can lead to loss of control and significant damage.