| Equipped with lifting platform as a climbing operation,is used to transport personnel and equipment to the specified working height for working equipment.With the operation platform is more and more widely used in the production and construction,the lifting platform stable operation,safety and reliability of the requirements are also constantly improved.The stability of M12 lifting platform is not high,there is a sense of shaking,there is a failure in the key link of the chain and wheel chain,the strength and performance of the mechanism should be improved.Firstly,the typical failure and the dangerous point locations are defined.Then Strength analysis is carried out,put forward reasonable suggestions to improve the mechanism force and the stability.① Through the position and assembly relationship between the columns,and the movement relationship of the pulley by connecting the columns,which establish the equations of motion and velocity in order to determine the displacement and velocity relationship among columns in the lifting process.lt Provides a theoretical basis for determining the position relation of the adjacent columns and analyzing the stiffness to clarify the position relationship of the columns in the dangerous position position.②The column platform force should be analyzed,the traditional static equilibrium equation is adopted,the whole platform and the single column were taken as the research object to establish equilibrium equation,to solve the unknown force in the whole and single column.Secondly,the principle of virtual displacement is used to solve the force of hydraulic cylinder.The virtual displacement of all the load is built through the kinematics analysis of each column.The constraint of hydraulic cylinder and working platform is unlocked and as an external force applied to the body,the virtual work equation is established to solve the hydraulic cylinder thrust.③Platform force analysis results and constraint relations between columns are used as boundary conditions,four section columns are analyzed by using the finite element static strength method.The maximum stress is 197.63MPa,occurred in the upper stress zone,where chain wheel is installed.The value is much smaller than the yield limit 345MPa,body static strength is to meet the requirement.④The stiffness analysis is mainly carried out from two angles:the deflection analysis and effect on stiffness of inertia sectional moment.Based on the geometric relationship,the top deflection caused by the installation gap is derived.The top deflection induced by the force and torque is calculated by using the moire integral method.Get the top deflection f= 23.90 mm<0.025hmax=84mm,in line with the standard requirements.The corresponding deflection range is obtained,which provides reference for the selection of column section.⑤Lifting platform stability refers to the ability to specify the conditions in the tip resistance.The moment balance method is used to calculate the stability moment and overturning moment to get the stability safety ratio K>1,Maximum permissible speed through the mechanism to curb the obstacle,the kinetic energy of 462kg·m2/s2 is less than the required potential energy 827.7kg·m2/s2,It shows that the stability is good. |
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