The Schaeffler UK automotive plant in Llanelli, South Wales, has been chosen to produce turbocharger ball bearings, with the start of manufacturing planned for week 21 this year.

The Schaeffler group’s production of these bearings is being transferred to Llanelli because the plant is deemed particularly suitable for the high-volume high-speed lower-cost production of these high-precision components, for which there is increasing demand world-wide.

Klaus Cierocki, president of Schaeffler’s engine systems business division, says: “The trend in the automotive industry is towards cleaner powertrain solutions and achieving CO2 reductions while still optimising the conventional internal-combustion engine. The down-sizing of engines leads to more opportunities for turbocharger applications.”

Schaeffler UK’s plant in Llanelli, which was established in 1957 and now employs 250 people, has been focusing on manufacturing mechanical tappets for the automotive industry.

More recently, a multi-million-pound investment programme in new plant and machinery has allowed Schaeffler to supply surface-coated engine components that cut fuel consumption and reduce CO₂ emissions; this investment also saw some 5,000m2 of the 20,000m² facility set aside for the manufacture of turbocharger ball bearings.

Dave Bate, Schaeffler UK plant manager, says: “We expect the demand for turbocharger ball bearings to run into millions over the next five years, with demand coming from a number of customers world-wide.

Manufacturers of turbochargers are being asked to provide more-compact higher-efficiency units that are more reliable, durable and affordable.

Originally, these turbochargers were only required for ‘high-end’ passenger cars, plus light-duty and heavy-duty trucks, but we are now seeing a shift in demand to include passenger cars with smaller highly efficient engines with lower CO2 emissions and improved fuel consumption. This has led to an increase in global demand for ball-bearing guided turbochargers.”

Design details

Turbocharger ball bearing assemblies are angular-contact bearings with ceramic balls, metallic cages, an anti-rotation device, an outer ring, a compressor inner ring, a turbine inner ring and a series of oil-flow control jets.

The bearings rotate at speeds greater than 150,000rev/min and can reach temperatures of up to 400°C in hot-shutdown conditions. The bearing assemblies are designed to be cooled by the flow of lubricating oil, and the bearing materials must resist extreme conditions over the complete ife of the turbocharger.

Compared to traditional joined-bearing turbocharger systems, ball-bearing-guided turbochargers offer benefits that derive from the change in the ‘friction mechanism’. Schaeffler says that ‘multiple rolling elements’ replace a ‘thin oil film in high shear’, significantly reducing friction (typically by up to 50%); these elements also offer even greater improvements during the first minute of an engine cold start.

With conventional hydrodynamic oil-filled turbocharger systems, the oil is very viscous in cold conditions, particularly during engine start-up; and the time taken to heat up the oil means that engine emissions suffer during this period.

With ball-bearing turbochargers, air is available to the system immediately on cold start-up, resulting in a more energy-efficient system with reduced emissions; the result is an increase in power, an increase in torque, and a 2.5% reduction in CO₂ emissions.

Mr Bate says that over the last year, Llanelli has invested much time and resources in preparing the new turbocharger bearing production line and training its workforce. “Training has been critical. Following a rigorous selection
procedure, we chose five people to lead our turbocharger ball-bearing production.

These engineers will set up and operate the machines initially, but as demand for the bearings increases, they will take a step back and supervise the new members of the team, training and supporting them as required.”

Many other Schaeffler employees have been involved in the transfer of production from Plymouth (Barden Bearings) to Llanelli. The Schaeffler locations in Plymouth, Llanelli and Herzogenaurach (group headquarters in Germany) worked closely together to ensure a successful start of production.

Mr Cierocki says: “Very tight tolerances combined with innovative manufacturing processes have been established to support this newly developed market segment — hence the extended production capabilities at our Llanelli plant.”