摘要
[目的]为满足大马力拖拉机不同作业工况下的负载和行驶速度需求,提出一种四区段液压功率分流无级传动系统。[方法]首先,确定无级变速器的传动方案,首次将中间轴式机械有级变速器和静液压无级变速器（HST）并联,基于等比传动的速度连续性和传动效率最优原则,确定机械变速器传动系统参数,然后,计算HST系统功率并对泵马达调速系统油路进行设计和元件选型,最后,基于AMEsim软件构建液压功率分流无级变速器及拖拉机整机仿真模型,对该变速器传动特性及拖拉机典型作业工况进行了仿真分析。[结果]该变速器可在0~50 km·h-1范围内实现无级调速,具有接近恒功率传递的段间转矩比分布,且在无级调速过程中具有最高44%的液压分流功率;分别使用HM2与HM1段进行犁耕作业,拖拉机行驶速度与发动机比油耗分别为8.5 km·h-1、215 g·（k W·h）-1和6.1 km·h-1、300 g·（k W·h）-1。[结论]该变速器结构紧凑,传动效率高,调速范围广且全程可实现无级调速,满足大马力拖拉机在不同工况下的作业需求,在同等作业条件下,使用较高的变速器工作段位与较低的发动机转速,可提高拖拉机的燃油经济性。
[Objectives]In order to meet the load and speed requirements of tractors under different operating conditions,this paper put forward a hydraulic power split stepless transmission system with four segments. [Methods]First of all,the transmission scheme of stepless transmission was confirmed,the scheme was the first to put intermediate shaft type mechanical transmission and hydraulic static transmission（ HST） in parallel,and based on the optimal principle of the speed continuity of geometric transmission and transmission efficiency,the characteristic parameters of planetary row and all the gear transmission ratio were identified. Then,the power of HST was calculated and the hydraulic circuit of pump-motor speed control system was designed with component selection. Finally,the simulation model of this hydraulic power split stepless transmission and tractor was established on AMEsim,and the drive characteristics of this transmission and tractor＇s typical operating mode were analyzed in the simulation. [Results]It can be shown that,the transmission designed realized stepless speed regulation within the range of 0- 50 km·h- 1,its torque ratio distribution between sections was approximated to constant power transmission＇s and the highest proportion of hydraulic split-flow power in the process of stepless speed regulation was 44%; respectively using HM2 and HM1in plough operation,tractor speed and engine fuel consumption were 8. 5 km·h- 1,215 g·（ k W·h）- 1and 6. 1 km·h- 1,300 g·（ k W·h）- 1. [Conclusions]Accordingly it can be concluded that,this transmission has the advantages of compact structure,high transmission efficiency,wide speed range and stepless speed regulation,so it can meet the operation demand of high-power tractors under different working conditions,and when it refers to the same operating condition,the use of higher segment and lower engine speed can improve the fuel economy of the tractor.
出处
《南京农业大学学报》
CAS
CSCD
北大核心
2016年第1期156-165,共10页
Journal of Nanjing Agricultural University
基金
江苏省科技支撑计划项目(BE2014134)
江苏省产学研联合创新资金项目(BY2014128-04)
关键词
大马力拖拉机
无级变速器
液压功率分流
无级调速
犁耕
high-power tractor
continuously variable transmission（CVT）
hydraulic power-split
stepless speed regulation
ploughing condition
