EVALUATION OF QUALITY INDICATORS OF “SHAFT-CUFF” PARTS AND ASSEMBLIES

The service life of the running gear, the drive line and other units of agricultural machines depends on the durability of sealing assemblies. The author lists reasons for the loss of sealing performance: surface wear along the inner diameter (87%), edge cracking as a result of aging and fatigue failure (14%), sticking of a cuff to a shaft with subsequent destruction of the former (9%). To analyze the parameters of new seals, a batch of cuffs sized 1.1-45×65-1 GOST 8752-79 in an amount of 200 pcs were studied. The paper presents some parameters for evaluating new and worn cuffs and shafts. The histograms and theoretical curves of the scattering of the interference fi t and contact pressure of the working edge of cuffs are presented. A one-factor experiment was conducted to analyze the relationship between the interference of new cuffs and the contact pressure on the shaft N = f (p). It has been found that these values are independent, as evidenced by the obtained correlation coeffi cient that is equal to 0.016. The paper lists characteristic defects of shafts: wear of the surface contacting with a cuff, scratches, cracks and corrosion damage of the surface. It is indicated that the shaft wear can be reduced by increasing the hardness of its surface. Reducing the wear
of the cuff’s working edge is possible due to the use of more wear-resistant and antifriction rubber.