In this article, we will learn what is steering system along with definition, components or parts, working, ratio, types, difference between power and mechanical steering. Let’s explore!
What is Steering System? Definition
Steering System Basics
The automobile is a large industry. Since the development of vehicles, newer features have been introduced over time. Cars have a crucial component and that is steering system. The primary goal of this system is to provide proper control of the vehicle to the driver. Hence, this way, the directional changes can easily be controlled. It ensures less effort exerted by the driver on harsh road surfaces. Additionally, it is significant for safety as well. The steering system’s safety, control, and ease of operating the vehicle improve performance.
Definition of Steering System
A steering system is a part of steering control that allows the driver to turn the vehicle in the desired direction while ensuring a perfect speed range control for safety. It can also be defined as the system that provides runs with the automobile in the required direction by turning the front wheels usually.
Historical Overview/Background
Let’s discuss a brief historical overview of the steering wheel existing since the 19th century. Alfred Vacheron took part in the very famous Paris-Rouen race of France in 1893, in which he fitted his Panhard with a volant (steering wheel). This race is considered one of the early known events where the wheel-shaped device was used to steer the vehicle. In 1898, the French manufacturer launched the steering wheel in various models. The instance marked steering wheels as the permanent components of automobile designs.
Since then, advancements in physics and technology have led to steering systems’ evolution. Nowadays, vehicles use a power steering mechanism that can be operated even with a touch of fingers. The steering wheels and steering mechanism are somewhat fading out with the invention of cars that drive themselves.
Components or Parts of Steering System
Components of the steering system are listed below:
Steering wheel
It is a control wheel operated by a driver to turn the vehicle in the desired direction. It comprises of traffic indication switch, light switch, windshield wiper switch, etc.
Steering gear
Steering gear helps turn the vehicle by transmitting the input of the driver’s steering to the steering linkage mechanism.
Steering linkage
This linkage constitutes tie rod, kingpin assembly, pitman arm, spindle, steering arm, ball joints, and drag link.
Steering shaft/column
It is fitted in a hollow steering column. This column rotates when the driver steers and helps to transfer the motion from the steering wheel to the steering gear.
Drop arm
Drop arm transmits the motion from the steering gear to the tie rod. It happens whenever one turns the steering wheel to left or right.
Steering arm
It is an arm that’s aids in the transfer of motion from the steering gear to the drag link.
Ball joints
They are ball bearings used for connecting the steering knuckle with the control arm.
Drag links
Drag link connects the steering arm with a drop armor, in some cases, with tie rod assembly.
Kingpin and left spindle
The left spindle, wheel, and tire are rotated about the kingpin through the torque achieved by the steering arm.
Left tie rod arm
The left tie rod and right tie rod are connected through the center link.
How Does Steering System Works?
Working Principle of Steering System
The basic working of a steering system is based on the phenomena of “turning.” It means that the wheels turn due to the conversion of rotary motion into angular motion by the steering system. The front vehicles are mostly turned, but the turning of rear vehicles also takes place in some low-speed vehicles such as a forklift.
Working Procedure of a Steering System
This section explains the working of a steering wheel based on the components mentioned above.
- Turning the steering wheel causes the steering column/shaft to rotate, and this motion is transferred to the steering gearbox. This steering gearbox has gears that safely transfer the driver’s input to the linkages for safe turning.
- The rocker arm of the steering gearbox is fitted to a pitman’s arm at one end. At the same time, the other end is splined with the help of a ball joint to a drag link.
- Hence, whenever the steering wheel turns left or right, the Pitman transfers the received motion from the steering gearbox to the tie rod. These tie rods are two; left and right. A centre link connects the left and right tie rod.
- The Pitman’s arm is attached to the steering arm with the help of a drag link, or in some cases, it may be attached to the tie rod.
- The steering arm helps transmit the turning force from the steering gear to the drag link. Hence, we conclude that the turning of the steering wheel aids in transmitting motion to the Pitman’s arm with the help of a gearbox which is then transmitted to the drag link.
- This motion is now transferred by dragging the stub axle, rotating about the kingpin. This way, the wheel of the vehicle is turned.
- A steering knuckle has a wheel hub connected to steering and suspension components. This knuckle assembly helps maintain a stable plane of motion when wheels rotate.
- Spherical bearings are called ball joints to connect the control arms and steering knuckles. It prevents dirt from getting into the system.
Hence, we conclude that the wheel’s turning produces rotation in the steering column while the gearbox is fixed at the end of this column. So, the process causes the cross shaft in the gearbox to oscillate. This cross shaft connects to the drop arm and is linked to the steering arm with a drag link.
In contrast, the steering components of both wheels are attached to the drag link with the help of tie rods. Operating the steering wheel will result in the back and forth motion of the knuckle. In this way, the rotary motion of the steering wheel is transformed into the angular action for turning the front wheels.
What is Steering Ratio? Calculation & Changes
The ratio of the turn of the steering wheel (in degrees) to the turning of the wheel (in degrees) is known as the steering ratio. As a result, the steering ratio equals the number of steering wheel turns divided by the degrees of deviation from straight ahead. If a deviation of 10 degrees requires 2.5 turns of the steering wheel, the steering ratio is 2.5/10 = 0.25 turns/degree.
The steering ratio is the number of degrees that must be turned on the steering wheel to pivot the front wheels by degree. The greater the steering ratio, the easier it is to steer the car. However, the higher the steering ratio, the steering wheel must be twisted more to achieve steering.
The operator provides a small amount of force to the steering wheel in the steering system. The front wheels experience a substantially greater steering force due to this movement. For example, pushing 10 pounds to the steering wheel can result in 270 pounds at the wheels in one steering system. The steering ratio causes this rise in steering force.
Calculation of Steering ratio
The steering ratio cannot be calculated mathematically. We can calculate only by moving the steering wheel and measuring the angle turned by the tires. The steering ratio is influenced by two factors: the steering-linkage ratio and the gear ratio of the steering mechanism. The steering linkage ratio is determined by the distance between the Pitman and the steering arm. At one end, the steering arm is affixed to the steering spindle, and at the other, it is connected to the steering linkage.
The linkage has a 1:1 ratio when the pitman arm and steering arm’s effective lengths are equal. The ratio is less than or more than 1:1 if the Pitman’s arm is shorter or longer than the steering arm. The pitman arm, for example, is roughly twice as long as the steering arm. This means that the wheels will pivot around 2 degrees for every degree the pitman arm swings. As a result, the steering-linkage ratio is around 1:2. The steering mechanism develops the majority of the steering ratio. The steering ratio is due to the angle or pitch between the worm gear and sector gear.
Changes in Steering ratio
To change the steering ratio, it is necessary to shift steering gear. This procedure necessitates the installation of the new steering gear. The vehicle’s new steering gear may be questioned as to whether it’s safe to use on the road or not. Furthermore, enough room is needed to replace the steering gear completely. A bigger steering pinion is fitted in the rack and pinion steering system to direct the steering ratio. Steering ratio changes might also be regarded as one of the causes of high expenditures.
Types of Steering Systems
Some of the types of the steering system are given below:
Rack & Pinion steering
A rack and pinion steering system comprise a pinion (a circular gear) and a rack (a horizontal kit). A circular motion is converted into linear motion by the mechanism.
Construction of rack &pinion steering: A Rack and Pinion gear set is sealed in a metal tube, in which each end of the rack faces out from the tube. Both ends of the rack are connected by a tie rod or an axial rod. Moreover, the pinion gear is also connected to the shaft of the gear.
Working of the rack and pinion steering system: A rack and pinion steering system comprise a pinion (a circular gear) and a rack (a horizontal gear). A circular motion is converted into linear motion by the mechanism. The gear spins and moves the frame When the steering wheel is turned, and the pinion gear is connected to the steering shaft. The axial rods are connected by a tie rod end to the spindle.
Variable-ratio steering system
Variable Ratio Steering is a subtype of the Rack & Pinion steering system. The tooth pitch on this steering system is different in the middle than at the ends. Whenever the steering wheel is close to its center position, the steering becomes less responsive. the whole wheel becomes more sensitive to the circular motion of the steering wheel when it is cranked towards the lock.
A variable-ratio steering system can improve the operating characteristic of both manual and power-assisted steering. A manual rack and pinion steering system should have a somewhat high steering ratio to offer an almost direct steering reaction for straight-ahead driving with minimal steering wheel angular corrective movement. In contrast, the steering wheel is a typical ‘center position.’
Recirculating ball steering
Recirculating Ball Steering is the most prevalent steering system in heavy automobiles. It is powered by a Parallelogram linkage, which keeps the Pitman and Idler arms parallel and absorbs large shock loads and vibrations.
Construction of Re-circulating ball steering system: The steering wheel is attached to a threaded rod at the end of the steering shaft. Unlike the Rack & Pinion type, the threaded rod is fixed. The gear teeth are machined into the surface of the block. Ball bearings are inserted into the rod’s threads. These ball bearings serve two purposes: reducing friction and wear in gear and fixing the teeth of the gear so that they do not break contact with one another when the steering wheel is turned.
How does a re-circulating steering system work?: The rod rotates when the steering wheel is turned. Similarly, the block moves when the wheel spins. The block then moves another gear, which carries the Pitman’s arm. As the gear rotates, the ball bearings in the threads recirculate.
Power Steering System
A power steering system is a mechanical device that makes it easier for the driver to steer or move the vehicle by increasing the steering effort required to turn the wheels.
How does the power steering system work?
The power steering pump compresses the hydraulic fluid and guarantees that it enters the vehicle’s power steering system, assisting the driver in its steering wheels. When traveling at normal speeds or when the vehicle is stationary, an electric or hydraulic fluid controls the power of the steering system, allowing the driver to steer the steering wheel with minimal effort.
The power steering system is designed to give artificial input regarding the forces operating on the wheels. A slotted rotor rotated in this mechanism, allowing steering fluid to enter the pump. The rotor continues to revolve as the steering fluid enters, transporting the fluid to the drain port. The fluid now introduces a reservoir into the steering system, which aids the steering mechanism in using the proper pressure to keep the wheels rotating smoothly.
Power steering, which is an important component of vehicle dynamics, combines multiple mechanical pieces at certain wrench angles to turn the car’s front wheels in reaction to passenger inputs through steering wheels,
Types of a Power Steering System
The power steering system is an advanced steering gear mechanism. The basic principle of working of the power steering system is based on the conversion of the steering wheel’s rotary motion into road wheels’ swiveling motion. The system works differently depending on the type of multiplier utilized. Let’s get into the following power steering systems for a better understanding.
HPS (Hydraulic Power Steering)
Hydraulic power steering comprises a steering gear with a cavity divided into two sections with a sealed piston fitted to a rack. The steering assistance is provided by the hydraulic fluid when it is pressurized at one side of the piston, and it returns to the reservoir from the other side.
The flow of hydraulic fluid is controlled and maintained by a valve connected to the pinion shaft. The whole design is mechanical, constituting fluid, belt, hoses, etc., and driving power from the engine.
EPS (Electric Power steering)
Electric power steering is also known as motor-driven power steering, which operates on an electric motor and not a hydraulic system. It’s a crucial technology for highly automated driving. Additionally, the electric interface aids in highly automated driving while at the same time ensuring safety. EPS is connected to the vehicle control unit and additional parts, resulting in safety, enhanced performance, and greater convenience.
An electric motor is fitted to the side of rack-housing, driving a ball-screw mechanism through a toothed rubber belt. The screw engages a spiral cut in the outside of the steering rack. A torque sensor is attached to the pinion shaft to provide steering assistance. This sensor signals computer control for when to provide the steering assistance.
Manufacturers are moving towards EPS since they are fuel-efficient and cost-effective. Additionally, it ensures greater convenience in driving because of more connectivity with the road. Also, it requires less maintenance than the hydraulic power steering system.
Electro-hydraulic Power steering
Electro-hydraulic power steering is the advanced version of the hydraulic system. It constitutes a hydraulic steering pump driven by an electric motor and not the engine. It is a hybrid system since it uses both electric and hydraulic components in its design.
Integral Power Steering
The integral power steering comprises a power-assist gearbox, power steering pump, hydraulic lines, and a hydraulic piston fitted inside the gearbox. A control valve, conventional worm, and sector-gear arrangement are present inside the gearbox. However, the control valve has several types which may be used in the integral power steering design.
The actuator lever and link connect the reaction contact valve to the thrust bearing of the worm shaft. The torque produced in the thrust bearing helps in the movement of the control valve and the opening and closing of the oil passage.
Linkage Power Steering
The linkage power steering comprises a power cylinder connected to a steering linkage. It also has a control valve whose one side is attached to the center-link/drag link. This control valve receives input signals from the steering wheel and steering gear. The valve in reaction opens the connection, which directs the hydraulic fluid towards the hydraulic ram by turning to either left or right.
The ram is attached to the steering linkage. The hydraulic liquid flow at one end of the ram’s piston keeps the power direction in control. The major drawback of linkage power steering is that it is easily damaged.
Mechanical Steering System
For smaller powerboats, mechanical steering systems provide good handling performance and safe operation. A steering wheel, helm, push-pull cables, and connection kits—hardware that connects your steering system to your boat’s or outboard engine—are included.
How does mechanical steering work?
The helm is the mechanism that translates the circular action of the wheel into a push-pull motion on the wire below the instrument panel. To rotate the helical core of the steering cable, various gears mesh with the steering drum.
To move the core of the steering cable, an alternate type uses three or more gears that mesh internally with the cable drum. Rack steering is the most effective mechanism for moving the cable, but it requires a tall rack housing that is difficult to conceal under many dashboards.
Difference Between Power Steering & Mechanical Steering System
- Power steering is a system that uses engine power to assist in steering the wheels. Mechanical steering refers to a steering system that uses mechanical force to steer. Manual or non-power steering is another name for mechanical steering.
- Steering is the process of directing the wheels in the desired direction. You should be familiar with automobile steering systems. The driver uses the steering wheel to regulate the course that the wheels take. The power steering system uses a source of power to assist in steering the wheels. Mechanical steering is a completely distinct style of steering in which the steering is done by hand. The majority of cars nowadays, however, have power steering.
- When we talk about power steering, we’re talking about either hydraulic or electric power steering. As a result, we can say that both electronic and hydraulic power steering are forms of power steering, and both have all of the characteristics of a power steering system.
- Mechanical steering systems, on the other hand, rely on the strength of human muscle. Because of the advantages of the mechanical aspect, automatic steering is also known as mechanical steering. To steer the cars in this method, greater effort is required. The driver’s force on the steering wheel is the only source of energy for the mechanical steering system. Power steering, on the other hand, always allows mechanical steering to be used; this may be useful in the case of an engine problem or a power assist system failure.
Applications of Steering System
Coming towards the applications of the steering system, it could be said without any doubt that the steering system is one of the essential parts of today’s vehicles. A vehicle is nothing without a steering system because that is the essential tool that helps a car move.
The wheels or tyres of a car always go for the rotational motion. The steering system plays its role in the wheel’s movement so that it converts the rotational motion of the wheels into the linear signal that further lets the car move in a linear motion. The rack and pinion steering systems are primarily used in
- The small cars or vehicles
- The small trucks
- SUVs
- Maruti 800
- Alto
- Wagon R
- SweftDezire
- Hindustan Ambassador mark 2
- Machine tools
- Pick and place mechanisms
- Gantries
The recirculation ball steering systems are primarily used in
- Older automobiles
- Big trucks
- Off-road vehicles, e.g. jeep
- Mercedes Benz
- BMW
Advantages of Steering System
As we know that there are two significant types of steering systems. The rack and pinion steering system and the recirculating ball steering systems. Some advantages of rack & pinion and re-circulating ball bearing steering system are the following:
Advantages of Rack & Pinion Steering System:
Weight: The rack and pinion steering system are made with very lightweight elements. The light weightiness of the rack and pinion steering system are used every day. As this type of steering system is used in a small car, its lesser weight becomes a great advantage for that car as it is not too heavy on the vehicle’s body.
Price: The rack and pinion steering systems are very reasonable price-wise. The spare parts, nut bolts, or gears are readily available everywhere at an affordable price range. Their lesser price does not mean that the quality of the product is low. The rack and pinion steering system are readily available in the best quality at the lowest prices, which is a big positive point for small car users.
Strength: The rack & pinion steering system is very robust. It has a firm body. Once that steering system is installed, it goes a long way. Moreover, this steering system can take on many heavy loads and is very shock tolerant. So, in the case of any unfortunate minor accidents, the steering system is completely safe.
Easy Conversion: This steering system is the best for small cars because it quickly converts the rotational motion of the tires into linear motion. Talking about the function of the steering system, this is one of the primary functions of the steering system to convert the rotational movement of the tires of a car into linear motion.
The rack and pinion do this very efficiently without causing any load o the body of the vehicle. This steering system is designed to exquisitely convert the rotatory motion of fast turning tires into a linear signal with the minimum loss of energy.
Control: This steering system gives the driver tighter control over the car or vehicle. This steering system helps the driver make sharp and immediate turns or direction changes very smoothly in an efficient way.
Steering Effort: Some steering wheels are tough to control. Sometimes the steering wheel is adjusted in the car so that it offers a lot of resistance while turning. It may be suitable for beginners, but it can be a headache for the pro drivers because they cannot play with the wheels the way they like. Some drivers are very accessible and professional in their driving style.
They demand a steering system that requires the minimum steering effort. Sometimes a car can come in front of the driver out of nowhere. At this point, high steering control is required. The steering system which works with the least amount of effort provided is the best. The rack and pinion come under the category of those steering systems.
Steering Ratio: The rack and pinion steering system have a constant yet varying steering ratio. The steering ratio is the calculation that tells how much the wheels will turn with the turning of the steering wheel. The rack and pinion system have a very suitable steering ratio compared to the type of cars it is installed in.
Gearbox: The gearbox of the rack and pinion steering system is very simple in its construction. It is very durable and reliable. Moreover, if there is any damage to the gearbox, it is easily repaired and replaced in a very affordable price range.
Advantages of the re-circulating ball steering system:
Support: It is said that in bigger cars, the steering system works as one’s hip joints. It is because the more significant vehicles or vehicles use recirculating-ball steering systems. This steering system is very comfortable to use. This steering system does not require one to use their hand more often. Small arm movements can control the cars’ whole motion and directional campaign. As a result, the driver must put the minimum effort while steering the vehicle.
Smoother Drive: This is the most significant advantage for people with limited mobility. This steering system works with the electric power steering system of the car, which automatically reduces the load on the vehicle. Moreover, it becomes way more manageable for the driver to have reasonable control over the car simultaneously.
Connection with Electrical System: This steering system works efficiently with all the electric features of the car. Some steering systems cannot work with the features of the causing a maniac for the drivers sometimes. However, In the case of the recirculating ball steering system, this is not the case. It easily adapts to the electrical features of the car and does not shun its working efficiency.
Comfort: This steering system is designed in such a way that it provides maximum comfort to the driver. So, if the driver is injured, this steering system will still work efficiently as it works on the least amount of effort provided.
Turning Aid: During the sharp turns, the recirculating ball steering systems tend to turn the tires so that they don’t get damaged by the grooves and bumps on the road. That is how this steering system provides maximum protection to the tires from wear and tear.
Skipping: One of the significant features of the recirculating ball steering system is that it prevents the tires from skipping on the roads. This feature helps the drivers follow the traffic rules and stay in their lanes because the tires cannot skip over the grooves and change the routes. It is designed to let the drivers drive over the bigger bumps or speak breaker very smoothly without causing any damage to the car.
Disadvantages of Steering System
The disadvantages of Rack & Pinion Steering systems are the following:
- The rack and pinion system work on the continuous functioning of only a few parts. It causes the leakage and wears of other parts that, as a result, need retirement or replacement after some time.
- The rack and pinion systems are suitable for driving cars on smooth roads. They do not provide much support if the vehicle moves on an unpaved or damaged road.
- It is very simple and light in construction, so it may have fewer damping features. The passengers and the drivers can feel the shocks and the noises.
- The resistance against the friction is significantly less in the rack and pinion system. This causes the wear and tear of the wheels. This may cause a problem in the smooth drive of the car.
The disadvantages of recirculating ball systems are mentioned as follows
- It does not operate well at high speeds. So, the drivers who have installed this steering system in their cars need to drive in a limited speed range.
- The force required to operate this steering system cannot be adjusted. Therefore, the drivers have to work with them the way they are manufactured.
- As the transmission is attached to the single drive shaft, this steering system cannot allow the driver to move one wheel in one direction while the other wheel is in a different order. If one wheel turns in a different direction from the other wheel, the car will lose its balance, and it may result in an unfortunate case of an accident.
- All the steering input is transmitted through a single shaft in this steering system. This results in the reduction of its efficiency of it.
- The friction cannot be adjusted because the power is transmitted through a single drive shaft.
- It does not contain any ball bearing to prevent the wheels from moving out.
- The cars with no front end can drift badly while taking turns at high speed. This makes the vehicle very unstable at higher speed limits.
Conclusion
In short, this article has briefly discussed what a steering system is? It gives detailed information about the manufacturing and components of a basic steering system and its functions. It briefly discusses the two major steering systems’ advantages, disadvantages, and applications. No matter what a car is, it does require a sound steering system with better steering control. These different steering systems are designed to support significant vehicles, including cars with a big body and vehicles with a small body.