Influence of pitch and exploitation on the frictional behaviour of the silent chains

The silent chain transmissions are widely used in automotive industry as part of the distribution transmission for the combustion engines. The investigation of friction loses in chains is important in order to find out the influence of their constructive and exploitation parameters. The paper presents the results of the tests performed on a test rig used in the case of transmissions with parallel axes. The main contribution of the paper is represented by determining the influence of speed, tensioning force, temperature and pitch on the friction loses of silent chains. Two types of silent chains are tested: LD6 with the pitch equal with 6.35 mm and LD8 with the pitch equal with 8 mm. The tests have been achieved with the following test parameters: the driver sprocket rotations with the values of 500, 1000, 1800 and 5000 r/min; the tensioning force with the values of 0.5, 1, 2 and 3 kN; the lubrication oil temperature equal with 40°C, 90°C and 115°C. Conclusions are drawn regarding the influence of the chains’ pitch and of the exploitation parameters on the frictional torque. The presence of boundary or mixed friction in the joints of the chain explains the frictional behaviour of the chain.