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1.
比例方向阀控气动缸动力机构建模   总被引:19,自引:0,他引:19  
讨论了比例方向阀气动缸动力机械建模问题,采用工作点线性方法建立了动力机构和四阶模型,对位置系统和力系统推导了它的状态空间和传递函数形式,气缸两腔的压力动态存在差异,并且这个差异导致无法使用负载压降这个中间变量,基气动系统的这个特点,本文没有导出伺服系统的特性,并研究了平衡点附近系统模型参数的获取问题,为定量分析打下基础。  相似文献
2.
环面节流静压气体球轴承承载力特性的实验研究   总被引:8,自引:0,他引:8  
为研究环面节流闭式静压气体球轴承的承载力特性,设计了试验轴承及测试装置,介绍了轴承加工工艺及其制造精度的检测结果,完成了轴承承载力特性的实验研究.实验结果验证了所采用的理论计算方法具有良好的工程计算精度.  相似文献
3.
气动系统管路流场计算中边界条件的处理分析   总被引:2,自引:1,他引:1  
为了深入研究气动系统的运动状态和各项参数的分布规律,根据气动系统运动的实际情况和运动过程,利用特征线法对气动系统的管路进行一维非定常流场计算,对管路进、出口处的节流口的流动状态进行合理简化,在边界条件的处理上引入压力回复模型和等压模型对节流口处的流动进行处理,并给出了两种模型的适用条件和范围。通过计算结果和实验结果的对比,验证了该方法的正确性,从而为处理气动系统的管路的进、出口边界条件问题提供了一  相似文献
4.
高速气缸压力反馈式缓冲阀研究   总被引:1,自引:0,他引:1  
提出了压力反馈式缓冲阀.对理想压力反馈式缓冲阀的仿真结果表明更大的缓冲阀节流口有效地提高了缓冲阀的自适应能力、稳定阶段缓冲腔的恒压有效地控制了活塞速度反弹.对以压力反馈式缓冲阀为核心的高速气缸自适应缓冲系统进行的仿真和实验研究结果表明当活塞最高速度在2.758~3.336m/s之间变化时,缓冲系统均使活塞以0.007~0.38m/s的速度到达行程终点,实现了对活塞速度变化的自适应缓冲.  相似文献
5.
本文针对斗轮挖掘机经常采用的水平切削方式作了较为详细的分析,在此基础上推导了水平切割时切削厚度、切削高度和切削宽度较为精确的计算公式,为斗轮挖掘机水平切削时的受力分析和功能计算提供了较为可靠的理论依据  相似文献
6.
依据田口玄一的质量工程学理论,建立尺寸锭封闭环的质量损失函数,考查各组成环与封闭环之间的函数关系,导出尺寸链的反计算、正计算、中间计算的公式。反计算时,考虑封闭环的用户极限,用户损失和每个组成的环的工厂损失,分别求出它们的工厂容差和公差。正计算是反计算求得每个组成环的公差之后,按照尺寸的分布规律和概率论原理求出封闭环的公差。中间计算时对未知组成环公差的决定不受已知组成环公差的制约。  相似文献
7.
In order to predict accurately the characteristics of supersonic flow in new type externally pressurized spherical air bearings under large bearing clearance and high air supply pressure, which could decrease their load carrying capacity and stability, a CFD-based analysis was introduced to solve the three-dimensional turbulent complete compressible air flow governing equations. The realizable κ-ɛ model was used as a turbulent closure. The supersonic flow field near air inlets was analyzed. The flow structures illustrate that the interaction exists between shock waves and boundary layer, and the flow separation is formed at the lower corner and the lower wall around the point of a maximum velocity. The numerical results show that the conversion from supersonic flow to subsonic flow in spherical air bearing occurs through a shock region (pseudo-shock), and the viscous boundary layer results in the flow separation and reverse flow near the shock. The calculation results basically agree with the corresponding experimental data.  相似文献
8.
In order to provide some theoretical guideline for the structure design of the new type externally pressurized spherical air bearings,the static characteristics and the factors affecting the static characteristics of the air bearings were analyzed.A finite volume method was adopted to discretize the three-dimensional steady-state compressible Navier-Stokes equations,and a modified SIMPLE algorithm for compressible fluid was applied to solve the discretized governing equations.The pressure field and velocity...  相似文献
9.
提出了一种新型的气体球轴承结构,其球头尺寸大于球窝尺寸,称为过盈型静压气体球轴承。采用三维有限体积法对此类球轴承的静态特性进行了计算分析,并与传统的间隙型和跑合型静压气体球轴承进行了对比,表明本文提出的过盈型静压气体球轴承在承载力和静态刚度方面均有显著优势。  相似文献
10.
The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneumatic system had disadvantages such as inherent non-linearity and variations of system parameters with working points. In order to improve the dynamic performance of the system, feed forward compensation self-tuning pole-placement strategy was adopted to place the poles of the system in a desired position in real time, and a recursive least square method with fixed forgetting factors was also used in the parameter estimation. Experimental results show that the steady state error of the pneumatic rotary position system is within 3% and the identified system parameters can be converged in 5 s. Under different loads, the controlled system has an excellent tracking performance and robustness of anti-disturbance. Foundation item: Project(50375034) supported by the National Natural Science Foundation of China  相似文献
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