Design Of Hydraulic System For 300t Straddle Hoist

Straddle hoist is widely used in the marina for lifting and conveyance,playing an important role in the vigorous development of domestic medium and small yacht industry.The unique advantage and application of hydraulic technology in 300 t straddle hoist is determined by the operating characteristics,but now domestic research on it is few relatively.In order to produce a good-performance straddle hoist by us,it is necessary to do research into its hydraulic drive system,combining the latest achievements of hydraulic technology.In this paper,the hydraulic system is divided into four circuits including walking,steering,lifting and jacking,according to the composition features.The analysis focuses on walking,steering and jacking hydraulic circuits,and the main contents are as follows:(1)Designing the schematic of the hydraulic system for each circuit,and analyzing the technical characteristics including: the speed control process and the differential force and speed control principle of walking circuit;the steering modes and operating characteristics of steering circuit;analyzing the working process of lifting and jacking circuits in different stations.(2)Doing research into dynamic characteristics of walking and steering circuits.Firstly,analyzing the load characteristics of the wheel including straight line walking,pivot steering and walking steering.Then,building the simulation model on AMESim platform,and describing the establishment of the model for circuit combining modeling process.Finally,doing simulation analysis on the acceleration performance and response to step load for walking circuit,and the tracking error,chamber pressure and output force of hydraulic cylinder for steering circuit.(3)Doing research into lifting circuit.Firstly,analyzing the load-sensing control principle and the secondary lifting decline phenomenon,and proposing relevant solutions for the phenomenon.Then,deducing a mathematical model for valvecontrol hydraulic motor and setting up the model of circuit on AMESim platform.Finally,doing simulation analysis on the secondary lifting decline phenomenon considers the relevant factors,including elastic modulus of the oil,volumetric efficiency of motor and load weight,and proposing a method to delay releasing the brake.The simulation results show that the delay in releasing the brake can avoid the secondary lifting decline effectively.(4)Analyzing the security features of 300 t straddle hoist,including the brake control for lifting,drag when error occurs and automatic oil temperature control.The test cases of various functions are described to verify the feasibility of the design,according to the actual operating conditions.Straddle hoist has the advantages of flexible walking and efficient operation,is the development direction of the future.Straddle hoist commonly used hydraulic transmission drive mode,the quality of the hydraulic system is directly related to the machine's performance.The analysis and research for hydraulic system in this paper has an important reference value to the design and manufacture of straddle hoist.