Reduction of PTO rattle noise of an agricultural tractor using an anti-backlash gear

An anti-backlash gear was developed and tested as a PTO rattle noise reducer for a direct-engine PTO driveline of agricultural tractors. Models of the anti-backlash gear and its driving gear were developed and used to simulate the relative angular displacement between them when idling. Computer simulations were also conducted to determine the minimum initial load of the anti-backlash gear for zero relative angular displacement. Performance simulation of the anti-backlash gear with different spring stiffness and initial deflections indicated that the PTO rattle noise by the impact could be eliminated by zero relative angular displacement and that rattle noise could be further decreased by increasing spring stiffness. In experiments the anti-backlash gear reduced the rattle noise by 11.4-16.9 dBA depending on the spring stiffness with zero relative angular displacement. A relationship between the stiffness and initial deflection of the spring is proposed for zero relative angular displacement. It is concluded that anti-backlash gear can reduce effectively the PTO rattle noise of the direct-engine PTO driveline of agricultural tractors when idling.