Research On Key Technology Of Articulated-Boom Loader Crane Design

The articulated-boom loader crane is a kind of combined lifting operation equipment that uses two sets of luffing linkage and multi-section telescopic boom.Because of its excellent folding characteristics,it is widely used in lifting operations at limits spaces.Due to the multi-DOF of the loader crane,the position of its lifting point is affected by multiple parameters,resulting in multiple postures at the same lifting point.Under different postures,there are large differences in the force status of each component of the crane,which makes it difficult to draw the operating performance curve of this type of product.This article analyzes the display form and influencing factors of loader crane from the perspective of usage and safety.It is concluded that the order of the determinants of the performance of this type of crane is: environmental,vehicle,system output capacity,structural strength.Moreover,it also explains the lifting weight sequence of the crane under different conditions: the lifting weight determined by the product structure strength,the lifting weight determined by the mechanism output capacity,the lifting weight determined by the stability of the vehicle,the lifting weight determined by environment.Based on the operating characteristics and working principle,this paper finds that the multi-section performance curve is more conducive to showing the product performance of the folding boom truck-mounted crane.At the same time,the performance curve of the telescopic-boom loader crane is mainly determined by the strength of each component,and the output capacity of the two luffing mechanisms and each telescopic cylinder.Then,it analyzes and verifies the boom system of the telescopic-boom loader crane using the equal moment model and equal strength theory.At last,the optimal performance curve of the crane is obtained through the full range simulation analysis,and the reliability of the curve is tested and verified by experiments.The content is as follows.Firstly,according to the product characteristics and lifting performance,the telescopic-boom loader crane is studied from the perspective of safety protection to the operator.And the results show that the priority of the factors affecting the performance of the crane and lifting weight sequence under different working conditions.On this basis,The performance of the telescopic-boom loader crane is determined by six aspects: the telescopic cylinder of the six-section telescopic boom,the first luffing cylinder,and the second luffing cylinder as the main actuators and the determined by the maximum load-bearing performance of the structural parts composed of the column,the first boom,the basic boom,and the first to sixth telescopic booms。Secondly,using analytical methods commonly used in engineering technology,the first luffing linkage mechanism,the motion equations of the first and second luffing linkage mechanism,and the effective arm of the crane’s luffing cylinder are analyzed.The calculation equations of the lifting point are given,with the variable amplitude cylinder length and the boom length as independent variables,which can be directly used in the program calculation.And the product operating range envelope diagram is drawn according to the calculation equations.Thirdly,according to the equal-moment model and equal-strength target,the maximum load-bearing capacity of the boom system of the telescopic-boom loader crane is calculated based on the sequence analysis of the six-section telescopic boom of the boom system,using the lifting capacity under the equal moment state and the maximum bearing capacity under the same strength as the judgment conditions.Then the finite element simulation of the components of the boom system is performed using APDL,and the maximum lifting performance curve is given.Through the analysis of the calculation results,the research conclusions of this subject are drawn: except for the maximum boom length,the lifting capacity of the boom system under equal strength conditions is higher than the capacity under equal moment conditions,indicating that the boom can be used as the state of equal moment in practice.Finally,according to the decisive factors of the product performance,the lifting capacity of the telescopic-boom loader crane under the full range is calculated using APDL,with the equal moment model as the calculation import condition,and the maximum output capacity of each mechanism and the maximum load-bearing capacity of the connecting structure as the judgment conditions.The product performance curve is given according to the priority of the performance influencing factors.Comparing the calculated performance parameters with related products,the performance is increased by 4.33% compared with that before optimization,the torque curve is relatively smoother,and the torque attenuation ratio has been increased from 87.48%to 90.99%.It can be concluded that the optimization and improvement effect is excellent.At last,the reliability of the lifting performance was verified through product tests.