A hub carrier is a large casting in a vehicle's suspension system that houses or works alongside the wheel hub, enabling the wheel to rotate and supporting movement for steering and suspension travel.
Understanding the Hub Carrier
Based on how it functions, particularly in a front-wheel-drive (FWD) car, the hub carrier plays a crucial role in connecting the wheel assembly to the rest of the vehicle's suspension.
Key Functions and Characteristics
- Housing or Supporting the Hub: The wheel hub, which allows the wheel to rotate and, in FWD cars, helps drive the wheel and swivels for steering, rotates either within or next to the hub carrier.
- Facilitating Swivel for Steering: To enable the wheel to pivot for steering, the hub works in conjunction with the carrier. The reference states, "To make this possible, the hub rotates in or next to a large casting called a hub carrier."
- Connecting to Suspension: The hub carrier itself is not rigidly fixed. It is mounted to the rest of the suspension components, typically using ball joints. This connection method is vital for allowing necessary movement.
- Enabling Suspension Travel: The ball joint mounting allows the hub carrier, and thus the wheel assembly, to move up and down relative to the chassis as the suspension compresses and extends.
- Physical Form: The reference describes it explicitly as "a large casting." This indicates it's a significant structural component, often made of metal (like iron or aluminum).
How it Works (FWD Example)
In a front-wheel-drive car, the hub must perform two primary tasks: driving the wheel (transferring power from the engine) and allowing the wheel to swivel for steering. The hub carrier supports the hub in these functions:
- The hub, which is connected to the drive axle, is positioned relative to the carrier.
- The hub spins freely within or beside the carrier, allowing the wheel to turn.
- The carrier is attached via ball joints to suspension arms (like the lower control arm and sometimes a strut or upper control arm).
- When you steer, the steering linkage pushes or pulls on the carrier (or a steering arm attached to it), causing the entire carrier-hub assembly to pivot around the ball joints. This swiveling is what turns the wheel.
- As the car drives over bumps, the suspension moves. The ball joints allow the carrier and hub assembly to move up and down, enabling the suspension to absorb shocks while maintaining the steering angle set by the driver.
Essentially, the hub carrier is the sturdy link between the spinning wheel hub and the static parts of the steering and suspension system, allowing for both rotation and controlled movement.
