Study On The Straightening Load Model Of Shaft Part

Automatic straighten technology straightenes shafts through automaticnumerical control straightener which is controlled by hydraulic press, it is a sort ofadvanced manufacturing technology. It is an important process in mechanicalprocesses to guarantee the product quality, and it is used extensively in machinemanufacturing industry such as automobile, tractor, engineering mechanism,machine tool and textile machinery. In the environment of competition, the qualitymind of enterprise is enhanced continually, so the product quality becomes the keyto the survival and development of the enterprise. Conventional straightener whichwas controlled by worker's experiences is disused by market gradually. Howeverthe development planning of our automatic shaft straightener is just underway andthe majority of theoretical investigation is unable to form systemic application. Sothe research of automatic straightener and the method of straightening possesses animportant value and significance. The research in the paper is a very beneficialexplore and attempt to straithten theory.The primary research in the paper as follows:Model of load straighteningWhen the deformation of metal exceedes the limit of elastic deformation, itenters plastic phase. In this phase, in despite of amount of deformation how toincrease alone, the ability of spring-go is no longer increased, or a lesser increase,and appears permanent deformation at the same time. So this phase belongs toelastic-plastic deformation phase. The straightening of shaft part belongs to thisphase. In the process of modeling, the research object is the single-bend shaft in the2-D plane. Through the analyses of the process for straightening shaft, there aretwo equilibrium relationships. (1)The first equilibrium relationship is the internalstress owing to external force F and the external force. (2)If unburdened theexternal force, the shaft part not only leaves residual stress, but also leaves residualdeformation. The residual deformation is equal to the original bend. On the basis ofelastic-plastic theory and some assumed condition, the external force F isintroduced as a parameter in the model.Data figure and finite element analysisThe piston rod of large arm cylinder in hydraulic excavator occurred flexuraldeformation after heat treated, it required to be straightened. On the basis of formerpressed straighten model, the straighten process of the piston rod was analyzed andcalculated. Then the paper studied the relation between the straighten load andinitial deformation when deformation curve, pivot span, load point and stuffattribute changed. Through the analysis and calculation, we can educe a conclusion.When the parameter of the model is changed separately, the relation between thestraighten load and initial deformation is invariability. In company with theincrease of initial deformation, the straighten load presents overt non-linearityincrease. Through the analysis of each parameter, we can calculate the straightenload exactly. So we can change the value of each parameter to get optimizedresults.Nowadays straighten technology is faced with slather high-strength metalstraightening mission. High-strength metal has a short yield flat or without it andan overt intensify characteristic, so we need to consider intensify impact. Thenormalization of intensify elastic modulus influences the quantitative estimates.Through the data figure and analyses, we can see the impact of metal intensifycharacteristic to the calculation of straighten load, so we can not neglect this impactin actual calculation, especially in exact calculation. The impact is aggrandized incompany with the increase of initial deformation.Straighten technical finite element computation is not only advisableness, butalso figure in a position is running up to higher precision in the company with thematurity of finite element technique and finite element software. At the moment,finite element software gets widely application such as ANSYS, which haveabroad application, best compatibility and quick computing. Through the availableresearch, we can see the finite element result and experimental data dovetailed verywell. Through the contrast of finite element computation and theory computation,we can prove the exactness of the model.Contrastive analysis between load and displacement modelIn the available straighten craft theory, most of the people found thetheoretical model which have straighten displacement as prior parameter accordingto the relate hypotheses. We can calculate recurved deformation according to initialflexural deformation and empirical formula, and straighten the shaft throughcontrolling the displacement of the rammer. The paper puts the load as the mainparameter, it can straight the shaft through controlling the load. Through the datacalculation, we can see the relation between initial deformation and recurveddeformation is linear, whereas the relation between initial deformation andstraighten load is nonlinear. Shaft part flexural deformation belongs toelastic-plastic deformation. In the whole deformation process, it contains theelastic-plastic deformation characteristics of the stuff, and the character is to benonlinear. So we consider this character fully in the computational process ofstraighten load, and it is closer to practice result. At the same time, we can control aquantity which is changed little by controlling a quantity which is changed more inthe shaft straighten process. So it is in favor of the controlling of straighten load insmallness deformation, and can advance straighten precision.After calculating the straighten load, we can control the hydraulics system andoutput the required straighten load. In the hydraulics system which is controlled byload, it required the hydraulic cylinder to maintain a fixed press under exiguitydeformation, I.E. exported definite load. It can be realized by designing pressuremaintaining loop. Hydraulic cylinder is the executor in the hydraulics system, itrealizes the working cycle containing quick forward, working forward, quickbackward and stop. After confirming the design considerations, we can ensure themajor parameter in the hydraulic system.ConclusionFrom the former analysis, we can know that the foundation of shaft straightenload model conform with the requirement of production practice, it is able toimprove the straighten precision. At the same time, model calculation result hasdefinite error, it needs deepen research in the following study. The research of shaftstraighten load model is a discussion to the straighten technology in existence. Theproduction practice experience will have a theory sublimation through deepentheoretical investigation, it will react on automatism straighten technology andproduction practice for the future.