高压容腔卸压过程分析与新型卸压阀的设计

发布时间：2018-06-26 23:22

本文选题：高压容腔 + 动量变化　；参考：《太原理工大学》2012年硕士论文

【摘要】：锻压机床在进行压力加工时,液压控制的工作缸要有快速下行、慢速加压、保压延时、快速回程、原位停止五个阶段。工作过程中,液压缸和液压系统需有很高的压力,保压结束后,油缸的工作腔和一部分液压管道组成的高压容腔,压力达到最大。高压容腔由于油液的压缩及管路的弹性变形等,贮存了大量能量,工作压力越高,高压容腔容积越大,贮存的能量就越大。在进入回程阶段时,需先释放掉保持在高压容腔中的液压能,该过程即为卸压,卸压过慢,会延长工作循环周期,影响锻件质量,卸压过快,将引起液压系统的剧烈冲击、振动和噪声,会对锻压设备造成很大破坏,影响锻压机床的使用寿命。因此,本课题的追求目标是,对大型压机高压容腔的泄压过程进行分析,在可容忍的冲击下,使泄压过程最快。本文首先介绍了几种常见的卸压过程,对其进行分析,指出其存在的问题,通过对卸压过程进行分析,得出影响卸压过程的主要因素有：高压容腔的容积、高压容腔的最高压力及泄流口面积大小,并从引起卸压冲击的根本原因动量的变化入手,指出通过控制流量的合理增加,来控制动量的变化,并得出压力与面积随时间变化的曲线图,为快速无冲击卸压阀的设计提供了理论依据。基于对卸压过程的分析,采用负载敏感技术,设计了新型卸压阀。该阀主要由三部分组成：液控单向阀、节流阀以及外控内泄式顺序阀。该卸压阀通过液控单向阀来控制卸压阀的开启,并在保压阶段起保压作用；而节流阀的作用主要是随负载改变节流孔口面积完成卸压；卸压结束开始回程主要是通过顺序阀来控制。对于卸压阀的设计关键在于节流阀芯的设计,通过列举数据,并对其进行分析,得出压力变化量与阀口面积变化量的关系式,并建立弹簧位移与压力变化的关系,以此得出节流阀口面积随位移变化的孔口形式。最后对该卸压阀的性能进行了分析,并对其试验进行了设计。
[Abstract]:When forging machine tool is working under pressure, the working cylinder controlled by hydraulic pressure should have five stages: fast downlink, slow pressure, delay of holding pressure, fast return, and stop in situ. During the working process, the hydraulic cylinder and the hydraulic system need to have very high pressure. After the pressure keeping is over, the working chamber of the cylinder and the high pressure chamber composed of part of the hydraulic pipe reach the maximum pressure. Due to the compression of oil and the elastic deformation of the pipeline, a large amount of energy is stored in the high-pressure cavity. The higher the working pressure, the larger the volume of the high-pressure cavity and the greater the energy stored. When entering the return stage, it is necessary to release the hydraulic energy kept in the high pressure chamber first. The process is pressure relief, which is too slow, which will prolong the working cycle, affect the quality of the forging, release the pressure too quickly, and cause the severe impact of the hydraulic system. Vibration and noise will cause great damage to forging equipment and affect the service life of forging machine. Therefore, the goal of this project is to analyze the pressure relief process of the high pressure chamber of the large press, and to make the pressure relief process fastest under the tolerable impact. In this paper, several common unloading processes are introduced, and their problems are pointed out. Through the analysis of the unloading process, it is concluded that the main factors affecting the unloading process are: the volume of the high-pressure chamber. The maximum pressure of the high pressure chamber and the size of the outlet area, and starting with the change of momentum, which is the root cause of the pressure relief impact, it is pointed out that the change of momentum can be controlled by controlling the reasonable increase of the flow rate. The curves of pressure and area changing with time are obtained, which provides a theoretical basis for the design of rapid non-impact relief valve. Based on the analysis of pressure relief process, a new pressure relief valve is designed by using load sensitive technology. The valve is mainly composed of three parts: hydraulic control one-way valve, throttle valve and external control internal discharge sequence valve. The pressure relief valve controls the opening of the relief valve through the hydraulic control one-way valve and acts as a holding pressure in the pressure holding stage, while the throttle valve is mainly used to discharge the pressure by changing the orifice area of the throttle orifice with the load. The end of the pressure relief start return is mainly controlled by the sequence valve. The key to the design of the relief valve is the design of the throttle valve core. By enumerating and analyzing the data, the relationship between the pressure change and the valve opening area is obtained, and the relationship between the spring displacement and the pressure change is established. Based on this, the orifice form of orifice of throttle orifice changing with displacement is obtained. Finally, the performance of the relief valve is analyzed and its test is designed.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH137

【参考文献】