Investigation of the Influence of Non-Flatness and Runout of Friction Discs on the Service Life of Machine Clutches

Abstract

In the manufacture of discs, it is important not only to ensure their specified geometric accuracy and correct shape, but to maintain geometric parameters during operation. The method of testing disks on the IKS-T inertial test bench is described. The main units of the test bench and the loading parameters of the disks are indicated. Research has been carried out on the influence of the runout and non-flatness of friction discs on the service life of the clutches. Bench tests made it possible to determine the optimal runout range of discs up to 0.8 mm, which ensures an increase in the reliability of the clutches by 30 % due to a decrease in the wear of the friction discs. In addition, the test results show that with a decrease in non-flatness from 1.2 mm to 0.3 mm, the service life of the friction discs increases by 16 %, i.e. wear of discs in the running-in mode with distortions in geometry occurs more intensively than for discs with a flat surface. With an out-of-flatness value of 0.3 mm, the discs acquire improved elastic characteristics. It was possible to determine that increased values of disc wear are observed mainly along the outer diameter, due to the runout and higher sliding speed compared to the sliding speed on the inner diameter. Calculated dependences of the limiting number of loading cycles on the beating and non-flatness of discs are presented. It was found that when testing discs with the non-flatness less than 0.3 mm, disc wear appears with the formation of “poppet” disc shape. For the purpose of imparting the correct shape to the products with the exclusion of “poppet” discs, a dynamic straightening with combined loading is proposed. The resulting calculated dependencies will be used in the design of industrial universal installations for cyclic alternating bending of friction discs.