Braking new ground with TMD Friction
Braking components specialist TMD Friction has outlined how its extensive research and development activity is helping to make brake pads and linings increasingly eco-friendly and more efficient, as well as promoting quieter and more comfortable commercial vehicles.
The company has been working in partnership with vehicle, axle and brake manufacturers for more than 135 years, developing brake friction solutions specifically to their needs.
It highlights the exceedingly high load that emergency braking can put through just a few square centimetres of friction component on a 40-tonne truck – adding that any compromise in quality can quickly become not just expensive, but even deadly in a worst-case scenario.
Secure bonding of the friction material to the backing plate is imperative to ensure CV brake pads are able to deal with extreme demands and loads, TMD Friction says.
It therefore uses the following mechanical processes in the manufacture of its Textar CV brake pads: steel plate with brass pins; cast plate with brass pins; cast plate with cast-on pins (integral cast plate); steel plate with weld mesh; and lightweight plate with stamped pins.
Even under extreme thermal loads, these processes guarantee permanent bonding of the friction material to the backing plate, says the firm, which also means the highest possible levels of safety and comfort.
For its friction materials, Textar uses only mixtures developed in-house and adapted individually for the specific application – such as truck, trailer, semi-trailer, city bus, coach or construction vehicle.
Further benefits are evident in lifespan, says TMD, as friction products are one of the most high-maintenance replacement parts. The more kilometres a brake pad can safely cover, the more economical it becomes.
The company also highlights its extensive research and development work into optimising noise, vibration and harshness (NVH) characteristics. As well as delivering a more comfortable ride for the driver, this could also be essential in some countries for access to city centres – for example, should driving bans be implemented for trucks that exceed certain noise pollution limits.
The Textar product portfolio encompasses more than 500 tailor-made pads and linings for disc and drum brakes for trucks, trailers, buses and coaches.
Responding to the steadily increasing pace of change in the marketplace has always demanded truly pioneering work, says the firm – for instance, its development of the material for T090 trailer drum brakes in close collaboration with a leading German axle manufacturer. Textar is the only OE supplier for these trailer applications.
Furthermore, big-name European truck manufacturers have been using exclusively Textar friction materials for many years in their original equipment, the company points out. T7400 remains the first choice OE material for disc brakes in city bus applications, it says – not least due to its good wear characteristics under frequent successive braking.
“Another major benefit of our brake pads and linings is that they are ready for use from the moment they are installed on the vehicle,” explained Dirk Schneider, chief of sales CV (OE) at TMD Friction.
“While we always recommend bedding them in slowly, we know from our customers that this is often not practicable in the stressful reality of everyday life. Our pads and linings play their part in making sure that safety and comfort don’t suffer under those conditions.
“Moreover, we use a special process called Green Coating to apply a thin layer to the material, which speeds up bedding-in.”
The Textar line-up is also complemented by brake discs as well as wear indicators and authorised accessories from brake manufacturers.
TMD emphasises the enormous value of research and development, and the rigorous testing programme its products are subject to. A team of 300 worldwide is at work in six development centres in Germany, UK, USA, China and Brazil to ensure the very highest quality standards.
“Textar means safety – no ifs, no buts,” said Willmut Röhling, senior manager vehicle programme at TMD Friction.
“That’s why it takes us up to three years to develop a brake friction product and put it through endurance testing before it comes to market.”
This means that no brake pad is installed without its performance and integrity first being thoroughly proven and verified on dynamometers.
At the top of the list are four different standard test programmes run on a variety of dynamometers. Examples include the measurement of friction coefficients under a diverse array of operating conditions, endurance testing of wear and comfort, and performance evaluation when brakes are hot.
This is complemented by comprehensive physical investigations carried out in the lab to assess material behaviour over the lifespan and under a variety of conditions (such as cold, heat and wet).
This step is also incredibly important in respect of environmental aspects, TMD says, as heat and pressure could potentially lead to the creation of environmentally harmful material compounds.
The company also puts its products through extensive test driving. For the development of a new friction material, the TMD Friction test fleet covers up to 300,000 kilometres conducting test drives on proving grounds, public roads, mountain passes and racetracks.
ECE Regulation 90 approval provides a legal protection for the customer and supplier with regard to the respective brake friction products, the firm adds, ensuring that the vehicle does not lose its registration if replacement friction products are fitted.
It describes the ECE-R90 requirements as “a good, although minimal standard based on certain criteria for which dynamometer verification alone is sufficient.”
Textar’s catalogue of criteria, especially in respect of brake performance, lifespan and comfort, is considerably more comprehensive, TMD says, meaning the quality of its products exceeds that required by law.
Willmut Röhling concluded: “Even if we can’t see the brake pad or lining ourselves, whether we’re a passenger on a bus on our way to work or a commuter on the motorway with a watchful eye on a truck looming in the rear-view mirror at the end of a traffic jam, we should never forget that it has a hugely important job.”
