【作者】 李凯；

【导师】 丛茜；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2020， 硕士

【摘要】 随着中国制造2025和十二五及十三五计划的推进和实施,农业机械化被上升到十大战略计划,我国的农业机械化水平实现高效快速发展,拖拉机在农业机械中占有非常庞大的比重。对拖拉机来说,悬挂系统的提升能力和安全可靠性对拖拉机整机使用性能稳定性起着重要的作用。因此,对拖拉机提升系统提升能力进行下线检测,对于判断拖拉机整机制造质量是否合格至关重要。拖拉机液压悬挂提升承载性能的检测是拖拉机重点检测环节,现阶段国内外的检测标准和检测试验基本是对拖拉机出厂性能进行检测,即针对拖拉机悬挂系统最大提升力、运动行程、静沉降等指标进行试验检测,检测试验准备周期和检测周期长、劳动强度大、且自动化程度低。而目前对于拖拉机提升系统的下线检测,即对提升系统额定提升力、提升行程、提升时间、提升次数和静沉降关键指标的全面检测缺乏相应的国家标准和成熟的方法。因此,本论文针对洛阳市某生产企业的要求,研究和设计了一套先进高效,检测指标全面的拖拉机提升系统下线检测液压加载试验平台。本试验台采用高效安全的液压加载方式、根据杠杆原理进行快速挂接、利用PLC自动化电控操控手段,能对不同型号不同功率拖拉机进行高效快速检测,检测范围涵盖提升系统额定提升力、提升行程、提升时间、提升次数和静沉降全面检测的指标,为拖拉机质量检测技术的研究提供参考依据。本文主要内容包括以下几个部分:(1)通过对拖拉机提升系统检测试验需求的研究,结合拖拉机工作情况和现有的开发经验,对设计的液压加载试验台工作原理和实际工况要求做了阐述。从不同的角度进行加载试验台方案的设计,对设计方案进行了评估和分析选择最终合适的设计方案,并利用UG对加载试验台的机械结构进行三维模型建立,完成试验台的总体结构设计。(2)加载试验台主要由机械电控装置和液压系统组成,其中液压加载系统是整个试验台的动力源以及主要的工作执行装置。因此,对于液压加载系统的设计、整个试验台的兼容配合度、以及液压泵站的安全节能性决定了整个试验台的使用效率与稳定性,本论文对液压系统进行设计,绘制原理图以及电控中的液压元件执行表,并对其原理和功能进行总体说明。(3)基于液压系统的设计,利用Amesim建立了试验台液压系统模型,选定合适的子模型及设定参数得到液压加载缸和电磁阀的工作曲线图,并对所得到的仿真结果进行分析,验证试验台的液压系统可靠性。(4)电控是整个液压加载试验台的控制中心,本文对试验台的电控装置进行设计,通过电控装置控制液压泵站为试验台提供动力,利用电控装置控制电机、电磁比例溢流阀和和电磁换向阀,从而控制液压缸的加载和试验动作,完成对电控系统的分析和设计。(5)完成试验台的搭建、安装和试验方法步骤的设计,对拖拉机悬挂总成进行提升能力的检测试验,并对设计的拖拉机提升系统下线检测试验台的性能进行评价。更多还原

【Abstract】 As the country adheres to the new development concept,China’s agricultural mechanization production capacity has made significant progress.Tractor accounts for a large proportion in the agricultural machinery market,Which is a very important machine in the development of modern agricultural machinery.The suspension lifting system is the necessary device for the tractor to use,During the work of the tractor,relying on the lifting system to achieve machine lifting and operation.For tractors,the lifting capacity and safety reliability of the suspension system play an important role in the performance stability of the tractor.Therefore,the downline inspection of the lifting capacity of the tractor lifting system is essential for judging whether the tractor manufacturing quality is qualified.The detection of the tractor lifting system is the key inspection link of the tractor.At present,the testing standards and testing tests at home and abroad are basically testing the factory performance of the tractor.That is to test the maximum lifting force,static settlement and movement stroke of the tractor suspension system.The test preparation and test cycle are long,the labor intensity is large,and the degree of automation is low.At present,there is a lack of corresponding national standards and mature methods for the overall detection of the tractor lifting system off-line detection,that is,the comprehensive evaluation of the rated lifting force,lifting stroke,lifting time,lifting times and static settlement of the lifting system.Therefore,this project is aimed at the requirements of a production enterprise in Luoyang City,researching and designing a set of advanced and efficient,comprehensive detection of tractor lifting system offline detection hydraulic loading test platform.The test bench is fast-mounted according to the principle of leverage,using PLC automatic electronic control means,safe and precise hydraulic loading mode,and can efficiently and quickly detect different types of different power tractors.The detection range covers the rated lifting force and lifting stroke of the system.Indicators for overall inspection of lift time,number of lifts and static settling.It provide reference for research on tractor quality inspection technology.The main content of this paper mainly includes the following parts:(1)Researching on testing requirements of tractor lifting system and Combining tractor work and existing development experience,The working principle and actual working condition requirements of the designed hydraulic loading test rig are expounded,and the design of the loading test rig is carried out from different angles.We select the final suitable design scheme by evaluating and analyzing the different scheme,and the UG pair is used.Load the mechanical structure of the test rig for 3D solid modeling and complete the overall layout of the test rig.(2)The loading test bed is mainly composed of mechanical electric control device and hydraulic device,and the hydraulic system is the power component and the execution device of the test bench,so the principle design of the hydraulic system,the matching degree and compatibility with the equipment structure,and the hydraulic pump station The safety and energy saving determines the efficiency and performance of the entire test bench.We designed the hydraulic system and drew the hydraulic system paper,and drew the hydraulic component execution table in the electronic control,and explained the principle and function of the whole(3)Based on the design of the hydraulic system,AMESim is used to establish the hydraulic system model of the test-bed,select the appropriate sub model and set the parameters to get the working curve of the hydraulic loading cylinder and the solenoid valve,and analyze the simulation results to verify the reliability of the hydraulic system of the test-bed.(4)Electric control is the control center of the whole hydraulic loading test-bed.This paper designs the electric control device of the test-bed,controls the hydraulic pump station through the electric control device to provide power for the test-bed,controls the motor,the electromagnetic proportional relief valve and the electromagnetic reversing valve through the electric control device,so as to control the loading and the test action of the hydraulic cylinder.In this paper,the use process and precautions of the electric control device are made Description.(5)Complete the construction and installation of the test-bed,and the design of test methods and steps,and carry out the offline detection test of the tractor lifting capacity,and evaluate the performance of the designed offline detection test-bed of the tractor lifting system.更多还原