Sitting Up for Consumer Comfort

In markets, such as the US and Europe, car ownership is declining in favour of mobility-on-demand services, such as City Car Club. Such services are growing so popular, in fact, that the European car sharing fleet is on track to reach 100,000 cars by 2020, a ten-fold increase since 2009. With this vehicle sharing in mind, the quality of the mechanisms used for seat adjustment is becoming more and more important to accommodate various drivers’ needs and individual preferences.

Furthermore, good seat adjustment is crucial for road safety, giving drivers a clear view of the road ahead, while also being able to reach the pedals easily. With so many drivers using the car, adjusting the seat each time, the seat mechanisms have to withstand frequent alterations, without succumbing to increased wear, tear or noise levels.

At the same time though, consumers want a luxury experience when they get in their car, as revealed by sales results for high-end marques in Europe in August 2015. They will be spending hours sitting on long journeys, so their seats need to be easily adjusted to ensure comfort and good posture support, with smooth, quiet seat mechanisms that stay in position, even during bumpy rides.

There is a number of seat adjustment elements in a modern car where things can go wrong, causing noises in the passenger cabin, or failing to provide the required level of support, negatively impacting on drivers’ experience. To keep things in check, automotive manufacturers are re-evaluating small parts such as structural fasteners and bearings that can make a difference in the performance of seat height, back tilt and seat folding adjustment mechanisms.

Both manual seat adjusters – still popular in Europe – and powered mechanisms – widely used in the US - require a lot of care during manufacture. Both are prone to breaking when overstressed by aggressive use or by passengers trying to move the seat when there is an obstruction, resulting in damaged levers and gears or burnt-out motors, and requiring costly repairs. A solution that automotive manufacturers are finding increasingly effective in creating high-quality mechanisms is the tolerance ring. These are radially-sprung frictional fasteners that, when used in manual and powered seat mechanisms, are capable of acting as simple mechanical slip-clutch controls. The tolerance ring’s wavelike protrusions can be customised so that it provides a perfect fit between mating components, yet is able to slip at a pre-determined torque level, protecting the lever or, in the case of a powered adjusters, electric motor from damage from overstressing, ensuring the long life of the mechanism without complicating the assembly process.

In addition, with up to 11 pivot points located throughout the seat, manufacturers need to ensure they do all they can to dampen vibration and reduce noise inside the passenger cabin. Selecting the right bearings for these points is crucial to minimise friction and vibration. Composite bearings, for example, feature a thick, lubricating liner of polytetrafluoroethylene (PTFE) that ensures a perfect fit between mating components to alleviate rattling and vibration while the car is moving for a noise free driving experience. The composite bearings’ robust metal backing means they support the smart design of modern lightweight seat frames, as they can withstand the increased loads experienced at bearing points without compromising on mechanism performance or durability.

Automotive manufacturers are evolving their vehicles all the time. Innovations are still being made to further reduce the weight of seat frames and mechanisms, while new technologies in the rear seats now allow for the increased level of flexibility only previously seen for the driver and front passenger. In the future, we can expect to see these trends continue, as well as the introduction of new technologies, such as "one-hand-operation" adjusters, enhancing convenience. Whatever the next few years hold for the industry though, choosing the right small parts will be crucial for manufacturers to meet trends and achieve the quality drivers expect.