New Equipment Enhances Marangoni’s Approach to Tyre Testing

Testing new products, verifying their conformity to international approval standards and the development of new solutions, notes Marangoni, are essential elements in the research performed by leading tyre manufacturers. To help it carry out these activities in the most scientific and detailed manner possible, the Marangoni Research & Development Centre in Rovereto, Italy has implemented a new tyre tester it calls “Ruota Strada”. This new unit is set up for the indoor testing of all types of tyre, including passenger car, industrial, earthmover and high performance products.

The introduction of the Ruota Strada tyre tester, developed within the framework of a research project aimed at automating the tyre production process and making it more flexible, represents the completion of the first stage of Marangoni’s plan to upgrade its Rovereto laboratory. The goal of this plan, adds Marangoni, is to acquire new knowledge at a group level that can be used to establish products, processes and manufacturing technology relating to new tyres and retreads, quality control, monitoring of the competition, as well as for studies on saving energy and respecting the environment.

The Ruota Strada tester has been used to conduct tests on the new low rolling resistance product lines the company is preparing to introduce throughout 2009. This list of products includes Marangoni’s E-logic car tyres, Ecomaster and Ecoenergy truck retreads, and Ringtread Energeco precured rings.

How it works

The Ruota Strada is a compact tyre tester that occupies a floorspace of only 100 square metres. It is completely soundproofed and climate controlled at a room temperature between 20°C and 30°C, in line with international regulations. The unit consists of a horizontally positioned steel drum driven by a powerful electric motor up to a perimeter speed of 420 km/h; tyres are fitted on two testing stations, served by hydraulic pistons to adjust the position and load in relation to the drum.

Tyres undergoing testing are fitted on the wheel hubs on each of the two stations and are typically driven by the main drum. One of the two stations, used to test tyres for passenger cars, light commercial vehicles and sports cars, performs three main movements to represent the alignment of a wheel fitted on the vehicle’s axle, simulating the vertical load, camber and drift angles when steering. To measure the forces and torques applied, as well as rolling resistance, a high precision slip ring is fitted on the wheel axle. The other station, used to test new giant tyres and retreads, performs just one movement to simulate the load and is fitted with a torsion meter to measure the torque opposing tyre’s forward movement. The operator can set the testing programs manually, in each phase selecting the speed, load and pressure, as well as camber and drift angles, save the test cycle and view the graphic analysis of the results on the screen. Safety features built into the Ruota Strada tester include an emergency stop device and anti-collision systems that are activated automatically if the tyre yields during testing.

Marangoni reports that the tyre tester can be used to set-up and conduct all tests required by the international certification standards and the unit applies the strictest accelerated fatigue and high speed test methods in order to simulate the most critical conditions of road use, as well as measure rolling resistance, analyse tyre dynamics and identify the input parameters for vehicle dynamics simulators required by the EU. The company adds that the new tyre tester “combines perfectly” with its automated MTM laboratory unit, which operates at its Rovereto facility as a system for the production of car tyres and an interactive means for permanent research into new advanced technological solutions for products, processes and machinery.

To fulfil the requirements of the Kyoto protocol, the European Commission aims to limit CO2 emissions and, as tyres contribute up to 30 per cent of such emissions, it has asked manufacturers to make a significant technological contribution to reducing fuel consumption, by lowering rolling resistance without affecting on environmental noise and safety, and with special focus on grip in the wet. Marangoni states that the equipment used to measure rolling resistance fitted on the Ruota Strada system will help ensure its tyres achieve the maximum rating envisaged by the new EC regulations, which come into force in 2012.