Highly fatigue-resistant and lead-free: new sputter bearings for commercial vehicle diesel engines
Stuttgart, September 2008–MAHLE is wrapping up development work on a new lead-free trimetallic bearing for commercial vehicle diesel engines. New bronze alloy and novel bearing layers applied in a sputtering process, based on AlSnCu alloys, provide maximum bearing strength.
Against the backdrop of EU directives for the avoidance of lead in the automotive industry, MAHLE is working intensively on bearings that work both for an environmental mindset and for the ever-increasing requirements of engine design. The new MCB15S2 sputter bearing is a CuSnBi bronze cast onto the steel back plate. After a bonding layer based on nickel and chromium, an aluminum alloy is applied as a running surface coating (AlSn30Cu). For both a sputtering process is used.
The bearing has thus far withstood loads of up to 100 MPa on the test bench. The goal for production input is loads of 120 MPa and higher. The combination of materials also provides the greatest durability, high wear resistance, and seizure resistance.
In contrast to other trimetallic bearings, the running surface coating on the sputter bearing is not applied galvanically, but using a sputtering process in a vacuum. The coating is very fine-grained and finely dispersed. The layer combines a remarkable hardness with a high conformability and best wear characteristics.
The MAHLE Group is one of the 30 largest companies in the automotive supply industry worldwide. As a leading manufacturer of components and systems for the combustion engine and related products, MAHLE ranks among the top 3 systems suppliers for piston systems, cylinder components, valve train systems, air management systems, and liquid management systems. MAHLE employs around 48,000 people at 110 production plants and eight research and development centers. In 2007, MAHLE achieved sales of over EUR 5 billion (USD 7.5 billion).