Strength and Clearance Optimization for Loader Lift Arm Joint for Backhoe Loader

Product engineering organizations are committed to provide solutions with quality and value to customers. Value improvement and efficient product engineering are the key to the success of all organizations. Continuous improvement helps a product to be competitive in the market.

In this paper, the author summarizes the detailed calculations which were carried out to resolve the reduced clearances between the engine enclosure and the Loader Lift Arm (LLA). The reduction in clearance was due to the transition from the Interim Tier 4 (iT4) engine enclosure to the Final Tier 4 (FT4) engine enclosure. The size of the engine enclosure increased whereas the loader-lift arm structure was kept the same. Due to the reduced clearances, when the LLA is raised, it had a higher chance to contact the engine enclosure. While performing backhoe operation with the LLA in the downward position, the engine enclosure could contact the LLA, which limits the operational capability of the backhoe. The study was challenged with constraints which did not allow change to any nearby or interacting assemblies like the engine enclosure, LLA cylinders, LLA service lock (refer Figure 3), and vehicle main frame. The calculations include stack up analysis, sectional calculation on shear tear out, tension failure analysis and bearing stresses across all the backhoe loader variants of current and new design. The robust calculation and detailed part analysis helped the design and analysis team to avoid Finite Element Analysis (FEA) and field testing due to thorough use of strong engineering principles. After the resolution was completed and implemented, no warranty cases were reported based on the design changes.