A drag link on a truck is a key component of the steering system responsible for transferring steering input from the steering gear to the wheels.
Based on the provided reference:
- Drag Links (DLs) connect the steering gear and the pitman arm at one vehicle wheel.
This connection allows the rotational motion of the steering gear and pitman arm to be translated into linear motion, which is then used to turn the wheel.
Drag Links vs. Tie Rods
While both are crucial steering components, the reference highlights a key difference between drag links and tie rods:
- Drag Links: Connect the steering gear/pitman arm to one vehicle wheel.
- Tie Rods (TRs): Connect the steering knuckles at the left and at the right wheel to transfer the steering forces, ensuring both wheels turn in coordination.
Essentially, the drag link initiates the steering movement from the steering box, and the tie rods ensure the opposite wheel follows the same steering angle.
Function and Importance
The primary function of a drag link is to be the direct mechanical link between the steering box output and the steering knuckle assembly on one side of the truck. Its integrity is vital for responsive and safe steering. As noted in the reference, companies like THK develop and produce DLs and TRs for various load applications, indicating their importance in handling the forces involved in truck steering.
In simpler terms:
- You turn the steering wheel.
- The steering box and pitman arm move.
- The drag link transmits this movement to one wheel's steering knuckle.
- Tie rods ensure the other wheel moves correctly relative to the first.
This system allows the driver to control the direction of the truck by changing the angle of the front wheels.
