Designing for efficiency: an exploration of optimized joint configurations in tyne cultivator design

Abstract In farming, soil ploughing for seedbed preparation is carried out using a 9-tyne cultivator. Friction commonly occurs at various joints, particularly when the tyne connects to the cultivator frame, which notably affects both performance and failure rates of the bolted joints. Previously, a bolt nut was used at this joint (joint 1), which caused rotation issues during ploughing. The tyne is now attached to the main frame via welded side plates, with springs providing preload on the joint. As the cultivator moves forward, the tyne exerts a draft force through the chisel plough onto the field. Continuous loading may lead to slight bending of the tyne, which can affect ploughing efficiency. To address the issue, an additional plate was welded onto joint 2, which initially reduced failures. However, problems persisted, particularly in joint 2, where significant frictional losses were still occurring. To further mitigate this, a bush pin was introduced in joint 3, enabling rotation within the bush and thereby reducing frictional losses and tyne bending. A comparison of joints 1, 2, and 3 was conducted, focusing on design parameters and the tractor draft force of the Swaraj 744FE model. The bush pin joint emerged as the most effective solution. Additionally, further optimizations through bush and pin size adjustments yielded promising results. The study highlights the reduction in friction losses, tyne bending, and FEM validation of stress analysis. Experimental and numerical displacement results under varying loads are compared for three types of joints. Joint 3 consistently shows superior performance, with experimental displacements of 0.55 mm at 0N, increasing to 1.25 mm at 10,000N, which aligns closely with numerical predictions. SEM analysis further reveals that Joint 3 has a smoother and more uniform surface, enhanced crack resistance, and structural integrity under stress compared to Joints 1 and 2. These findings validate the suitability of bush pin type joints for high stress and wear resistant applications, supported by their improved mechanical durability and numerical accuracy.