Structural Strength Analysis Of Con-rod Splitting Clamp And Geometric Parameters Influence

Connecting rod fracture splitting technology has many advantages such as fewer procedures, good-quality products, high production efficieny, saving energy and material, high economic benefit,etc. It provides a good-quality, high-efficieny, low-cost, clean approach to process connecting rod. The technology marks the development of engine connecting rod manufacturing field. The key whether connecting rod fracture splitting technology can be applied successfully in mass production lies in splitting quality, moreover splitting quality mainly consists in the gearing feature of fracture surface and the success rate of fracture splitting. In order to replace the bar and the cap accurately in fracture surface after splitting, stable and reliable working performance connecting rod splitting clamp should has stable and reliable working performance,high reciprocating precision. Enhancing the performance and extending service life of connecting rod splitting clamp will be very important for raising the efficiency of splitting manufacture and reducing production costs.This paper regards connecting rod splitting clamp as the research object, process in two aspects of clamp material and structural strength analysis, with the purpose to enhance its service life and working performance. The major work and conclusions of present paper are summarized as follows:1. The material of connecting rod splitting clamp and its heat treatment process must be selected properly. The materials of pull-rod and splitting block are respectively 40Cr, Cr12MoV. The heat treatment process of 40Cr steel can be: 920℃quenching+790℃quenching +200℃tempering. The heat treatment process of Cr12MoV steel can be: 1100℃prequenching +980℃conventional quenching +240℃tempering.2. The three-dimensional model of connecting rod splitting clamp is created by software Catia and its structure is analyzed and illustrated at the same time.3. Clear and simplify geometric model of connecting rod splitting clamp under the environment of Catia software, import the simplified model to Hypermesh, then establish the finite element model for structural strength analysis. The key technological problems which include meshing, material character, contact definition, boundary conditions, loading case and etc has been dealt with. Finally input the numerical model to solver Dyna ,the von-mises stress distribution pictures of connecting rod splitting clamp are obtained. The results indicate that the maximum stress which each component of original connecting rod splitting clamp bearing is lower than the yield strength of its material, no plastic deformation occurs, structural strength meets the requirements of use. The vulnerable points are respectively the maximum stress point on the wedge surface of pull-rod and the maximum stress point on the internal groove wedge face of moving block, the relation of these two points where pull-rod and moving block contact with each other in splitting process is corresponding.4. The cuneal angle of pull-rod, the cross section length-width ratio of pull-rod and the bottom fillet radius of splitting block are three main geometric parameters of connecting rod splitting clamp in this paper. Based on original connecting rod splitting clamp ,change the third parameter from small to big when the other two parameters keep constant, adjust the clamp model, analyze the structure strength of new model by finite element method , study the influence law of each geometric parameter on the structural strength of splitting clamp. The results are as follows:①The change of each geometric parameter has little effects on the location and shape of equivalent stress distribution, but the stress level will shift greatly.②Cuneal angle is the main geometric parameter influencing on the maximum stress of pull-rod, which decreases as cuneal angel increases. When cuneal angelαis up to 9o, the maximum stress level of pull-rod reaches the minimum.③The cross section length-width ratio of pull-rod is the main factor affecting the maximum stress of static block, which increases with increase of cross section length-width ratio. When cross section length-width ratio x is equal to 0.9940, the maximum stress level that static block bearing reaches the minimum.④The bottom fillet radius of splitting block is the dominating parameter affecting the maximum stress of moving block, which decreases as bottom fillet radius increases. When the bottom fillet radius r is up to 5mm, the maximum stress level that moving block bearing reaches the minimum. 5. The maximum stress level that each component of the connecting rod splitting clamp bearing significantly increases instead of decreasing When cuneal angle of pull-rod, cross section length-width ratio of pull-rod and bottom fillet radius of splitting block are respectively 9o, 0.9940, 5mm.