Design of a Twin Disc Test Machine

Twin disc test machines are widely used to carry out tribological tests. Often, by using these test machines real component contact conditions, such as the contact between gear mating teeth, are experimentally replicated. Gearboxes are mechanical transmission systems extensively used in the automotive and aeronautical industries. Several R&D activities are carried out around the world in order to improve the performances of these components. The main areas of R&D for these components are: design, materials and lubricants. Bespoke gear test rigs have been built in order to test innovative design of gears, new heat treatments, surface coatings and lubricants. These test systems can be grouped in three main groups (types): Full scale gear box test systems, gear test systems and simplified (basic) test systems. Full scale gear-boxes development tests can be very expensive and generally such tests are carried out only at the very last stage of the development process and quite often only if product certification is required. Gear test systems are most commonly used. Normally the test sample is a single pair of mating gears. By using this type of rig it is possible to replicate (quite accurately) the loading and environment conditions of a gear pair in a gearbox. Due to the high costs of gear manufacturing the test sample cost can often be the major cost of a test campaign. In order to reduce test costs a first screening can be carried out using a simplified test system known as Twin Disc Test Machine (TDTM). In this paper the design, the construction and the commissioning activities of a TDTM are described. The project is being carried out by AM Testing as part of a wider research project (Lifing Dentature) in collaboration with the Dipartimento di Ingegneria Civile e Industriale (DICI) of Pisa University and Avio Propulsione Aerospaziale.