Research Of The Chucking Power Of The Heavy-loaded Forging Manipulator

The research and analysis of clamping force of forging manipulator have a direct impacton manipulator’s overall design and they are crucial for giant overloaded manipulator’development which is needed in extreme manufacturing. Considering the contact status of jawand workpiece when different manipulator jaws clamping workpiece, there are three methodsto calculate the clamping force of forging manipulator which are based on the workingcondition of friction grab, considered the jaw surface convex tooth factors and based onprolapse of clamping workpiece in allowing deflection condition. Three calculation methodsof the clamping force are derived by computational analysis and model simplification. Andaccording to the results from calculation and analysis, the main influencing factors affectedsize of the clamping force are obtained which are jaw structure size, convex tooth structure onthe surface of the jaw, the clamping workpiece sagging deflection angle and so on.Taking imported300kN heavy forging manipulator as example, validity of threecalculation methods of the clamping force are verified and analyzed. The results show that theclamping cylinder size which calculated by calculation method based on the friction holdingforce differed with the original design was the largest. The calculation method of theclamping force considered influence of convex tooth jaw surface is insufficient, but throughthe analysis found that due to the jaw surface with convex surface extrusion slot interaction,convex tooth have increased the effect of friction between jaw and workpiece, jaw withprotruding teeth is more advantageous to manipulator clamping stability compared with flatjaw. And the clamping cylinder size reached by clamping force calculation method based ondrooping allowed deflection of clamping workpiece is most close to the original design and itis more effective compared with other two kinds of calculation methods in the design ofmachine operation.Jaw clamping force is clamping cylinder output force through the clamp levermechanism to jaw, and it shows that jaw clamping force is the main basis to determineclamping cylinder size. Jaw clamping force will happen very big change due to the change ofthe jaw opening size when jaw in different diameter workpiece clamping, which resulting inthe clamping cylinder size is difficult to determine, jaw clamping instability and so on.Through research and analysis of the relationship between the jaw, forceps rod forcetransmission ratio and clamping force jaw opening size, the function relation between the jawclamping force, clamp lever force transmission ratio and the jaw opening size is deduced.With300kN forging manipulator as an example to analyze, the analysis results showed thatthe clamp lever mechanism in the process of forging manipulator clamping work can adjustjaw clamping force and low the output force of clamping cylinder and it also can improve theforging manipulator jaw clamping stability. The importance of reasonable design of clamplever mechanism to forging manipulator clamping work was illustrated.Combined clamp lever mechanism constraints of the overall size of clamp lever mechanism, the design method of clamp lever mechanism is concluded by theoretic analysisconsidering the effect parameters of clamp lever body structure on the force. According todesign method of clamp lever mechanism, the design and calculation of400kN and800kNheavy forging manipulator clamp lever mechanism has carried on, the calculation of structuralparameter values has been compared with parameter values of equipment clamp levermechanism in use and the result is basically onsistent. The stability of clamp rod clamping indesign had analyzed as well, results shows that the design of clamp lever mechanism meet theusing demand of the forging manipulator and it can effectively adjust the jaw clamping force,thus verified the forceps rod mechanism design method has validity and rationality.