Analysis And Research On Step-variable Digital Hydraulic Shift Mechanism Of Loader

The loader is widely used in various engineering fields such as highways,railways,ports,construction,hydropower,etc.It is one of the most widely used construction machinery.In our country,the transmission form of the loader has evolved from the initial mechanical type to the current hydraulic mechanical type to the hydraulic transmission type,and has made great progress compared with before.However,the hydraulic mechanical form still has shortcomings such as insufficient traction and low efficiency.With the overall improvement of the technical level of the hydraulic industry and the continuous improvement of efficiency,the form of hydraulic transmission is gradually becoming the mainstream.However,the domestic research on the hydrostatically driven loader has only been paid attention in recent years.The transmission theory of the transmission system is rarely seen in the literature,so it is necessary to study the loader hydraulic shift theory.This article takes the YN917 G small loader as a research object,introduces the concept of digital hydraulics,designs the digital hydraulic transmission system of the loader,analyzes its shifting theory,formulates the shifting strategy,and uses joint simulation methods to verify the simulation.First of all,in-depth understanding of relevant information on automatic transmission technology at home and abroad,comprehensive analysis of the defects and deficiencies of existing technology,analysis of the current key shift technology research,to determine the research ideas and content of this article.Secondly,the digital hydraulic transmission system of the loader walking system is designed,and according to the principle of conservation of power,the engine and the digital pump,the digital pump and the digital motor,and the digital motor and the external load are dynamically matched to complete the digital pump and the digital motor.Selection.Through the reasonable matching of the engine and the hydraulic transmission system,the engine can be operated in the economic zone as much as possible to improve the engine energy efficiency.Thirdly,through the analysis of the digital hydraulic transmission system,according to the different shifting goals of the starting acceleration condition and the shoveling condition,different control methods are adopted for the engine,digital pump,and digital motor.Control mode.Then,the fuzzy control method is selected to formulate the shift strategy.In order to enable the engine to run in the economic zone,the engine speed and motor torque are selected as fuzzy parameters,and the fuzzy theoretic domain is determined.After fuzzy,fuzzy reasoning(knowledge base),anti-fuzzification,their shift control strategy is formulated.The simulation analysis provides a theoretical basis.Finally,the AMEsim software and Simulink software in MATLAB are simulated through the S-function interface to verify the shift control strategy of the loader's starting acceleration and shoveling conditions respectively.The feasibility of the system and the shift control strategy formulated can basically meet the shift requirements of the loader under two operating conditions.The research in this paper provides a new idea for the design of the drive system of the loader and has a certain reference significance for the design of the hydraulic drive system of the construction machinery walking system.