Cold Performance Testing And Improvement Of External Gear Pump For Tractor

In this dissertation,according to the tractor transport requirement for using the hydraulic steering system in winter of high latitudes and cold region,a kind of triple external gear pump applied on tractor was tested and improved in order to solve the cold performance issues(low oil flow,big volumetric efficiency drop,severe pump damage).Based on the testing result and data analysis,the pump structure design was optimized,and after test verification and continuously improvement,the final design Teflon coating low temperature pump could fulfill the requirement of cold performance and had no big volumetric efficiency drop when back to ambient temperature.The main research contents and result are shown as below:(1)Based on the specific introduction of the main hydraulic system,hydraulic steering system,tractor external gear pump basic principles and structure,the common gear pump was tested in low temperature,and through the data analyzing and pump disassembling,the structure optimizing plan was proposed.(2)In order to solve the cold performance issues,the size of pump inner oil transition path and steering pump bushing low pressure side were enlarged to develop a new low temperature gear pump.Tests were held again to verify the new design,and to find insufficiency for further optimization.(3)After Teflon coating was applied on the bushing and sweeping pressure was increased,the bushing abrasion resistance and pump volumetric efficiency of the low temperature gear pump got obviously improved.The new Teflon coating pump could fully meet the needs of low temperature use,and also past the reliability and durability tests.Thereby,the issues of tractor winter use in high latitude and cold region was completely solved.