Steering wheels are one of the essential parts of a car, but only a few people know how they work. Although there are various steering gearbox designs, the working principles are the same.
In this article, we will answer the question of how does a steering box work and all other things you need to know about your car’s steering system.
What is a steering box?
A steering box is a key component in a vehicle steering system that converts the rotational motion of the steering wheel into the linear motion needed to turn the wheels. It uses a gear mechanism, typically a worm gear or recirculating ball design, to amplify the driver’s input, making it easier to steer. The steering gear box connects to the steering linkage, which then directs the wheels.
Common in older and heavy-duty vehicles, steering boxes are renowned for their durability and lower maintenance needs. However, they can be more complex and provide less precise feedback than modern rack-and-pinion systems.
What are the components of a steering box?
The automotive steering gearbox system comprises several parts that all contribute to a safe and seamless driving experience. They include:
Steering wheel
The steering wheel is a car steering mechanism to direct the vehicle’s motion. It assists the driver in controlling the car. It includes a light switch, a wiper switch, and other components.
Steering shaft
The steering shaft rotates together with the steering wheel when it is turned and, thus, transfers motion to the gear box steering. The shaft can be found in the hollow steering column.
Steering gear
One end of the pitman arm is splined to the rocker arm of the steering gearbox, while the other is attached to the drag link by a ball joint.
Steering linkage
This component connects the steering to the wheels. The function of this steering gear component is to make turning much easier. It comprises a pitman arm, ball joints, drag link, steering arm, tie rod, spindle, and kingpin assembly.
Pitman arm
Also known as the drop arm, the pitman arm transforms the steering gear’s output torque into a mechanical force applied to the drag link. A split joint connects it to the sector shaft of the steering gear.
Ball joints
A ball joint comprises a ball and a socket, allowing the steering knuckle and control arm to move together. Each wheel has a ball joint that serves as the pivot point. A safe and comfortable ride is made possible by the ball joints.
Drag link
Drag links connect the steering system to its pitman arm. The drag link pushes and pulls the steering arm during vehicle motions, which causes the wheel to move.
Steering arm
The steering arm is fastened to the steering knuckle. It assists the driver in maneuvering the vehicle safely and steadily.
Tie rod
The tie rod is an adjustable rod attached to both the arms of the left and right. Together, they help to transmit pressure and force in a car.
Left spindle and kingpin
The left spindle, wheel, and tire are rotated about the kingpin by the torque produced by the steering arm.
Steering stops
Stops are used to control the angular deflections of the front wheels as well as to regulate tire wear and tear.
How does a steering gear box work?
The steering box operates by converting the rotational motion of the steering wheel into linear motion to turn the vehicle’s wheels. When the driver turns the steering wheel, this motion is transmitted through the steering column to the box’s input shaft.
Inside the steering gearbox, a gear mechanism, such as a worm gear or recirculating ball system, amplifies the force. This amplified force then moves the sector shaft or output shaft, which is connected to the steering linkage. The linear motion from the steering linkage turns the wheels, enabling precise steering control with minimal effort.
The rack and pinion and steering box are the most frequently used types of steering systems in newer car models.
The rack and pinion system
The rack and pinion steering technology convert rotational motion into translational or periodic motion. The pinion (gear wheel) is enclosed in a housing at the base of the steering column, and its teeth fit into the rack, a long horizontal bar with straight rows of teeth.
When the pinion is turned, the rack oscillates. Track rods connect the rack’s ends to the road wheels. The steering column is connected to the rack through a universal joint, which prevents the steering wheel from being uncomfortably tilted sideways.
The steering box system
This system uses a different power steering working principle. Here, a worm gear inside a box is at the base of the steering column. Worms are threaded cylinders that resemble short bolts. Imagine twisting a bolt with a nut attached so that the nut moves with the bolt. The worm gear works similarly, and rotating the worm causes anything inserted into its thread to move.
The moving component can be a big nut, a peg or roller attached to a fork, or a sector (a gear wheel segment), depending on the design. The worm drives the closest front wheel by moving a drop arm that is connected to the steering arm by a track rod.
A steering arm and another track rod connect the car’s central track rod to the other side, where it connects to the second front wheel. The far end of the center track rod is kept level by a pivoting idler arm.
Types of steering gear box
There are eight different types of steering gear box design. They include:
- Cam and double lever steering gear
- Cam and peg steering gear
- Cam and roller steering gear
- Rack and pinion steering gear
- Recirculating ball nut steering gear
- Worm and ball bearing nut steering gear
- Worm and roller steering gear
- Worm and sector steering gear
How do I test my steering box?
To test a steering wheel box, the vehicle has to be lifted with the weight kept on the wheels. You’ll need someone to help turn the tires while you check underneath the car. You can drive onto a series of ramps to do this safely, but they must be lying on a level surface directly beneath the wheels.
Put the car in gear and release the handbrake. To check for leaks and wear, examine the steering box. If the oil level in the box is low, it probably means there’s a leak.
By rotating the steering wheel while the car is still, you can also test for over-turning. The maximum amount of rotation you should be able to make before the road wheels move is 7cm, measured at the rim.
Seek the services of a car mechanic if you notice any abnormalities like vibration due to faulty rack during the checks.
What causes a steering box to fail?
The use of steering systems enables the driver to keep his truck under control. However, when steering and suspension systems malfunction, they can impede the driver’s control of the vehicle and cause a catastrophic accident.
Steering systems can fail due to defects in the design and manufacturing process or improper vehicle maintenance. Other possible causes of steering system failure include pump defects, clogged hoses, steering fluid leaks, contaminated power steering fluid, and worn power steering belts.
Like other mechanical issues, steering malfunctions exhibit warning signs before failing. This may be in the form of finding it difficult to turn the wheel or the steering wheel becoming loose or vibrating. The driver can prevent costly and risky outcomes by identifying these signs and addressing them.
Final words
Driving would be difficult or impossible without the steering gear to translate and magnify the input from the steering wheel. At this point, you will no longer ask how does a steering box work. I’ve also outlined the causes of steering box failure and signs to watch out for when they go bad.
This information will help you understand if something is wrong with your vehicle and save you time and money in the long run.