METHOD OF RESTORING THE WORN SURFACE OF A REDUCTION GEAR SHAFT IN A ‘SHAFT-TO-COLLAR’ CONNECTION USING A REPAIR BUSHING AND POLYMERIC MATERIALS

The authors prove the feasibility of applying a method for restoring the worn surface of a reduction gear shaft in a “shaftsleeve” connection using a repair bushing and a polymer material. It is recommended to use selective assembly with a transition fi t with the maximum possible interference fi t of 0.02 mm, and the maximum possible clearance of 0.16 mm. The experimental samples of repair bushings are made of thin-walled high-quality pipes made of steel 30ХГСА GOST 8734-75. The sleeve was fi xed on the shaft using the Unigerm-6 anaerobic polymer composition. An analysis of the test results showed that the shear strength does not correspond to the manufacturer’s data for the considered size of the fi t, but the strength values are higher than permissible ones. The dispersion of the obtained force values is not large and correlates with the clearance sizes in the samples. The study confi rmed the composition polymerization in a clearance of approximately 0.3 mm. The recommended maximum possible clearance of 0.16 mm ensures suffi cient strength of the coupling and the centering accuracy of the workpiece on the shaft (at the maximum possible shaft runout of 0.18 mm). To ensure tightness in the fi t, it is proposed to heat the bushing before
installation to 150°C, which is suffi cient enough to obtain an interference fi t but does not affect the properties of the polymer composition.