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The Study Of The Clamping Force Of The Heavy-duty Forging Manipulator’s Jaw

Posted on:2014-01-06Degree:MasterType:Thesis
Country:ChinaCandidate:J H ZhangFull Text:PDF
GTID:2251330401476503Subject:Mechanical design and theory
Abstract/Summary:Request the full-text of this thesis
Until recently, the studies on workpieces of the forging manipulator’s jaw,always simplify the surfaces of the jaw, which contact the workpieces, to flat ones,and ignore the effects that several rows of crowned-teeth have on heat resistantworkpieces. Through the studies, it has been proved that, regardless of rows ofcrowned-teeth, if the maximum load of rigid axial forgings have been mechanicallyanalyzed by frictional contact clamping, three issues can be found: Firstly, how todetermine the friction factors of the contacting surfaces; Secondly, the calculatedchucking power cannot reflect the actual application effectively; Thirdly, it is hard tocontrol the contacting length between jaws and workpieces, which does no good inthe forging process. By virtues of the analysis on issues related to friction grabbing,an actual working condition element has been found that the crowned teeth of the jawhave some influence on the chucking power.The situation between the jaws and the workpieces is to be simplified to theimpact between the crowned teeth and the squeezed slots, which perfectly fits theactual working situation. This thesis divides the jaw chucking process into two states:the crowned teeth of the jaw squeeze the heat resistant workpieces, which can bedefined as the clamping state; Or the state that the dents in the crowned teeth of thejaw and workpieces keep the workpieces stable. In both states, the chucking powerand the clamping power are offered by the same clamping cylinder. By means ofstudies and comparisons, this thesis has based on the bigger clamping force tosimulate two states.Through the analysis above, this thesis mainly deals with the clamping force whenthe jaws are clamping. Take the jaw clamping workpieces of a40-ton manipulator asan example, the software ANSYS can deliver a static analysis result on the lateralcompressive stress,which is formed by the different depths when the jaw is clampingthe workpiece. On the other hand, DEFORM-3D can simulate the yield stress onworkpieces when the crowned teeth of the jaw are making the corresponding indenteddepth on them. Compared the lateral compressive stress with the yield stress, there isa conclusion that the depths made by the latter are deeper than the former. Accordingto the rules asked by the workpiece indented depth that meets the requirements, andthe time that is needed when the jaw gets to the state of clamping, the relativeclamping power can be worked out. It can be known from the process of the crownedteeth of the jaw’s clamping the heat resistant workpiece simulated by DEFORM-3D,that the jaw’s clamping time is related to the jaw’s clamping speed, which cannot beminimized or maximized indefinitely. Because the clamping speed is proportional tothe clamping power, the faster, the tighter, and vice versa. Therefore, to find anappropriate clamping speed is to find a proper clamping time. It can be achieved by managing the clamping time, and changing the opening angle and the tooth number ofthe jaw to optimize the clamping force. In this way, an optimized jaw and a relevantoptimized clamping force are available.Via the studies on the clamping force, this paper has found out a way to optimizethe clamping force, and the optimized clamping force has offered an effectiveoptimizing basis for the entire physical design of the nippling lever.
Keywords/Search Tags:Manipulator, jaw, Simulation, Dents, clamping force, Optimization
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