How a vehicle’s function can affect its steering needs

Louise Davis

Eric Sonahee explains the need to understand a vehicle’s function in order to ensure the right parts and systems are included in the design from the start

Steering systems have come a long way since 1894, when the first steering wheel was installed in a vehicle taking part in the Paris-Rouen race.

Despite their often deceptively simplistic function, in specialist vehicles, steering systems have specific needs that can affect the steering components installed.

According to the dictionary definition, a steering system comprises of the ‘mechanical parts of a car or other vehicle, which make it possible to steer’.

However, in specialist sector vehicles, like those used for passenger transit, the military or emergency services, steering systems must be engineered to handle specific applications and varying requirements with ease.

Speed and precision

According to Nancy Caroline’ Emergency Care in the Streets, 'an ambulance needs to be able to do four things; start, steer, stop and stay running'.

Yet, these large vehicles that are contending with congested roads and time sensitive situations require precise steering capabilities to cope with the demands.

In the design stages of vehicle manufacturing, understanding factors like the overall weight capacity of the vehicle, including equipment and people, is vital in choosing appropriate system components.

For instance, ball and suspension joints or universal joints (UJ) that have been designed by steering system manufacturers for the specific needs of the vehicle will help aid precise steering in emergency situations.

Terrain and testing

In contrast to the high-speed, precise needs of emergency vehicles, military service vehicles are often required to travel through unknown road and weather conditions and must be able to cope with a multitude of scenarios.

Of course, the safety of military personnel is paramount, making the selection of components and pre-manufacture testing even more important.

Rigorously testing components under the load or forces it may encounter will establish an accurate fatigue life of the parts and system as a whole.

Using test rigs and assault courses that simulate the type of conditions the vehicle will contend with out in field will also provide useful data to design teams.

Speaking with your component manufacturers about any specific requirements, like ensuring parts are coated in paints capable of withstanding certain chemicals or varying temperatures, for instance, can establish safety levels for the vehicle and its passengers.

By working with engineers, like those at Pailton Engineering, who can put steering components through rigorous testing can make all the difference for long term safety and resilience. However, it’s not just military vehicles that can be put to the test.

Safety and comfort

Passenger vehicles that undertake lengthy journeys and can be subject to inclement weather and varying weights should also test components during the design stages of manufacturing.

Environmental testing on component reactions to weather protection treatments, like salt spray, will help extend the lifecycle of the parts.

Testing against incidents like curb strikes will also showcase the impact on the steering system in advance of the vehicle being on the road.

Drivers of coaches can also be in position for long periods of time, where tiredness and discomfort can be significant factors to potential accidents.

Supporting the tilt and telescopic movement of the steering wheel, allowing individual drivers to find the optimum position, will ease their discomfort on long distance journeys.

Regardless of the type of vehicle being designed, having a sound knowledge of the conditions or issues affecting the vehicle when on the road, or off-road in some cases, can influence the specifications of components needed to keep the vehicle moving smoothly and safely.

By ensuring you understand your vehicle’s applications, there’s certainly no need to reinvent the steering wheel, despite it being over 120 years old.

Eric Sonahee is a design and development engineer at steering system specialist Pailton Engineering