Describe how a rack and pinion steering, a parallelogram steering, and a worm and roller system operate.
The correct answer and explanation is :
Rack and Pinion Steering:
The rack and pinion steering system is one of the most commonly used steering mechanisms in modern vehicles. It consists of two main components: a rack and a pinion. The rack is a flat, toothed bar, while the pinion is a small gear that meshes with the teeth of the rack. When the driver turns the steering wheel, it rotates the pinion. The rotation of the pinion moves the rack from side to side, which in turn, turns the wheels of the vehicle.
This system offers precise and direct control, as the amount of rotation in the steering wheel is directly proportional to the movement of the rack and the wheels. The simplicity and responsiveness of the rack and pinion system make it ideal for passenger cars.
Parallelogram Steering:
The parallelogram steering system is commonly found in older vehicles or larger trucks. It involves a linkage mechanism made up of multiple arms and joints. The key components include the steering box, a pitman arm, an idler arm, and drag link. The system works by converting the rotational motion of the steering wheel into the linear motion that turns the wheels.
When the steering wheel is turned, the pitman arm connected to the steering box moves in an arc, which pushes or pulls the drag link. The drag link then moves the idler arm, which is connected to the steering knuckle on each wheel. This system forms a parallelogram shape, ensuring that both wheels turn by equal amounts, regardless of the steering wheel’s rotation. While this system offers good durability and stability, it is not as responsive or efficient as the rack and pinion.
Worm and Roller Steering:
The worm and roller steering system uses a worm gear and a roller to convert steering wheel rotation into motion that turns the wheels. The worm gear is a screw-like gear that meshes with a roller, a cylindrical component. As the driver turns the steering wheel, it rotates the worm gear. The rotation of the worm gear moves the roller, which is connected to the steering linkages that turn the wheels.
This system is often found in older vehicles or those with heavier, more challenging steering requirements. It offers a compact design and high torque, but its main drawback is that it tends to produce more resistance in steering effort, especially at low speeds. However, it provides stability and precise control for larger vehicles.
Each system has its own advantages and is chosen based on the design needs of the vehicle, balancing factors like precision, stability, and ease of use.