柱塞泵组件球面缝隙流动特性分析

球面缝隙流动常见于多种机械结构,如柱塞泵中的球面配流副、球铰副等,然而针对球面副半径不等及存在偏心的缝隙流动特性研究较少。针对2个半径不相等的球面元件形成球面缝隙且其球心存在一定偏心时,根据球坐标系下的N-S方程对其缝隙中流体的速度分布、压力分布、泄漏流量及流体的承载量进行了分析,得到了相应的解析表达式,依此可知,半径相等且球心存在一定偏心时球面缝隙中流体的相关解析表达式;同时,得到了仅与球面缝隙流动自身结构有关的球面支撑泄漏系数和球面支撑承载系数,进一步为形成球面缝隙的机械结构(如柱塞泵中的球面配流副、球铰副等)相关设计提供理论参考;最后以柱塞泵中球铰副形成的球面缝隙为例,对其缝隙中流体的压力分布、速度分布等参数进行了分析。     

考虑有效体积弹性模量的柱塞泵流场仿真分析

为提高柱塞泵的寿命和安全可靠性,确定柱塞泵合理的工作范围,运用FLUENT对轴向柱塞泵的运动特性进行仿真分析,研究了油液的含气量、变转速、温度与柱塞泵出口流量脉动之间的关系。仿真结果表明:油液的含气量对油液压缩性产生很大的影响,对泄漏流量影响较小;负载压力一定时,主轴转速超过2 600 r/min左右时,容积效率随着转速的增大而减小;压缩流量和泄漏随着温度的升高而增大。模型的准确性得到了实验验证,为开展柱塞泵的非线性动力学及故障演化机理等方面的研究提供了有效的工具。     

A11VLO190轴向柱塞泵柱塞副泄漏与润滑特性研究

将轴向柱塞泵柱塞副的泄漏看做偏心圆环缝隙的流动,使用Matlab进行仿真,分析得到了柱塞副泄漏量与负载压力、配合间隙、工作转速和斜盘倾角的关系。采用有限差分法求解二维雷诺方程,该文在考虑油膜动压效应和挤压效应的条件下,得到了柱塞在缸体内的倾角、柱塞自转速度、进口压力对柱塞副油膜分布压力的影响,为提高柱塞副的效率、改善润滑、减少摩擦磨损和增加使用寿命提供了一些参考意见。     

斜盘式轴向柱塞泵泄漏量的分析与计算

通过对斜盘式轴向柱塞泵泄漏途径的分析研究,得到了奇偶数泵的泄漏量计算公式,并对泵在不同参数下的泄漏量进行了仿真分析,为进一步研究泄漏量对奇偶数斜盘式轴向柱塞泵实际流量及脉动系数的影响提供了较好的理论依据。     

变流量轴向柱塞泵恒压阀性能优化

变流量轴向柱塞泵输出压力的稳定性是衡量性能的重要指标,恒压阀性能对压力稳定有很大影响。利用AMESim建立变流量轴向柱塞泵模型,设置恒压阀不同高压弹簧刚度和回位弹簧刚度进行仿真分析,以变流量轴向柱塞泵输出压力波动幅度和压力降低值为参考,仿真分析发现此工况下高压弹簧刚度为350 N/mm、回位弹簧刚度为10 N/mm时变流量轴向柱塞泵输出压力最稳定;计算控制阀滑阀副不同间隙对应摩擦力并进行仿真分析,发现在控制阀阀芯两端直径差值为4μm、控制阀阀芯和阀套平均间隙为13μm、泄漏间隙为15μm时,泵输出压力整体最稳定;控制阀阀芯开口为正开口时,能提高负载减小后的压力值,阀芯开口为0.03 mm时,泵输出压力更稳定。     

介质温度对柱塞泵性能影响的研究

针对某钢厂使用的A4VSO-250轴向柱塞泵,探讨了柱塞泵的工作原理,并且通过理论和实验的方式研究了油温对柱塞泵工况下泄漏流量、容积效率以及机械效率的影响,从而分析了温度对柱塞泵性能影响.     

变粘度条件下静压支承滑靴副的研究

本文对变粘度条件下的静压支承滑靴副进行了一定的理论研究和分析，通过计算机仿真，得出了滑靴副泄漏流量和支承反力不仅与中心油室压力有关，而且还与流体的粘温系数、粘压系数、密度和比热容等有关的结论，为高速高压轴向柱塞泵的设计提供了一定的理论依据。     

轴向柱塞泵柱塞与缸体孔泄漏及工艺分析

为了提高轴向柱塞泵的容积效率及整体寿命,研究了柱塞和缸体孔的泄漏流量与缸体孔的转角关系,通过Matlab仿真了其曲线图,得出了泄漏流量随着缸体孔的转角增大而变大,而根据泄漏的标准在正常工作的情况下不能超过0.25ml/min,确定了其间隙在范围内其泄漏流量是较小的,为了得到这个间隙进一步对柱塞和缸体的工艺进行了详细的分析,最终通过千分尺测量柱塞与缸体孔的配合间隙是符合设计要求的,从而提高了轴向柱塞泵的容积效率和整体的寿命。     

基于AMESim的A10VNO泵内泄漏故障注入分析

根据A10VNO斜盘式轴向柱塞泵的工作原理,在AMESim中建立柱塞泵仿真模型,并对仿真模型进行了改进.以柱塞副的偏心环缝间隙为研究对象,分析柱塞泵内泄漏的原因.利用故障注入技术的思想,将AMESim中BAF02泄漏子模型的径向间隙作为影响泵内泄漏主要参数.通过改变柱塞副环缝间隙的大小仿真得到压力、流量曲线,从而实现柱...     

斜盘式轴向柱塞泵变转速特性的对比研究

斜盘式轴向柱塞泵的低速工况性能是影响整个伺服电机驱动泵控系统效率的重要因素。通过数学模型分析选择最优化的仿真模型,研究并得出定量柱塞泵在变转速工况下的流量特性,结合数学模型和仿真模型,确定了定量柱塞泵在变转速工况下的性能,得到了不同转速下斜盘式轴向柱塞泵的压力波动和流量特性,为探索伺服电机驱动的斜盘式轴向柱塞泵控系统的性能提供了依据。     

Measurment of fluid film thickness on the valve plate in oil hydraulic axial piston pumps (Part II: Spherical design effects)

Tribologtcal characteristics in the sliding parts of oil hydraulic piston pumps are very important in increasing overall efficiency In this study, the fluid film between the valve plate and the cylinder block was measured by using a gap sensor and the mercury-cell slip ring unit under real working conditions To investigate the effect of the valve shape, we designed three valve plates each having a different shape One of the valve plates was without bearing pad, another valve plate had bearing pad and the last valve plate was a spherical valve plate It was noted that these three valve plates observed different aspects of the fluid film characteristics between the cylinder block and the valve plate The leakage flow rates and the shaft torque were also investigated in order to clarify the performance difference between these three types of valve plates From the results of this study, we found that the spherical valve plate estimated good fluid film patterns and good performance more than the other valve plates in oil hydraulic axial piston pumps     

On the instantaneous and average piston friction of swash plate type hydraulic axial piston machines

Piston friction is one of the important but complicated sources of energy loss of a hydraulic axial piston machine. In this paper, two formulas are derived for estimating instantaneous piston friction force and average piston friction moment loss. The derived formula can be applicable for piston guides with or without bushing as well as for axial piston machines of motoring and pumping operations. Through the formula derivation, a typical curve shape of friction force found from several experimental measurements during one revolution of a machine is clearly explained in this paper that it is mainly due to the equivalent friction coefficient dependent on its angular position. Stribeck curve effect can easily be incorporated into the formula by replacing outer and inner friction coefficients at both edges of a piston with the coefficient given by Manring (1999) considering mixed/boundary lubrication effects. Novel feature of the derived formula is that it is represented only by physical dimensions of a machine, hence it allows to estimate the piston friction force and loss moment of a machine without hardworking experimental test.     

Relation between pressure variations and noise in axial type oil piston pumps

Pressure variation is one of the major sources on noise emission in the axial type oil piston pumps. Therefore, it is necessary that the pressure variation characteristics of the oil hydraulic piston pumps be clarified to reduce the pump noise. Pressure variations in a cylinder at the discharge region and the pump noise were simultaneously measured with discharge pressures and rotational speeds during the pump working. To investigate the effects of the pre-compres-sion and the V-notch in the valve plate, we used the three types of valve plates. In this research, it is clear that the pressure variation characteristics of axial type oil piston pumps is deeply related to the pre-compression and to the V-notch design in valve plate. Therefore, we could reduce the pump noise by using the appropriate pre-compression angle and the notch design that are between the suction port and the discharge port in valve plate.     

开路式轴向柱塞泵的研究

本文介绍一类新的柱塞泵原理,它具有无泄漏回油、可自冷却、自润滑、多输出、压力高、效率高、寿命长、重量轻、结构简单、使用方便、节能、可制造各种性能的新泵,可改造目前广泛应用的轴向柱塞泵等优点。实践证明原理正确,工作可靠,性能优越。     

转速对EHA泵柱塞副柱塞位姿及泄漏量影响仿真分析

斜轴式轴向柱塞泵作为电动静液压作动器（Electro-hydrostatic actuator,EHA）液压系统的重要元件,高转速、高工作压力是实现其小型化、轻量化的重要手段。柱塞副是斜轴式轴向柱塞泵中重要的两对摩擦副之一,对斜轴式轴向柱塞泵的工作状况起着直接影响。随着缸体转动,柱塞在缸体柱塞孔中的位姿朝着各个方向不断变化,柱塞副泄漏量也随之变化。为准确得到高速高压下柱塞副的泄漏量并给出解释,充分考虑柱塞受力情况,通过对离散化的柱塞副油膜雷诺方程和力平衡方程进行迭代求解,使用柱塞端面偏移量来确切描述了柱塞在缸体柱塞孔中的位姿随转速的变化情况,据此给出了柱塞副泄漏量模型,分析了转速变化对柱塞位姿和柱塞副泄漏量的变化的影响。结论为EHA泵的设计提供了适当的理论指导。     

提高轴向柱塞泵性能指标的新方法

用开路式原理改造闭路式泵，是一种提高轴向柱塞泵综合性能指标的新方法，这种方法不用更换轴向柱塞泵中的任何零部件，只是改动其中几个零部件的形状或尺寸，就可以达到自冷却、自润滑、去掉泄漏回油管路、提高自吸转速、降低泵温、提高使用寿命的目的。     

Driving mechanism of tapered pistons in bent-axis design axial piston pumps

In order to assure the quality of the bent axis design axial piston pumps driven by tapered pistons, it is necessary to know the characteristics of force applied to tapered pistons and the mechanism for driving the tapered pistons. Since they are able to perform both reciprocating and spinning motions in cylinder block, it is difficult to understand the driving mechanismand-tomeasure the forces applied to tapered pistons experimentally. In the presem study, the theoretical mechanism for driving the tapered pistons is studied by use of the geometric method. The driving area of tile tapered pistons is measured by measuring the strain of a cylinder forced against a tapered piston using an electric strain gauge and a slip ring. The forces applied to tapered pistons is also investigated with the change of discharge wessure and the rotational speed As a results of this investigation, it is concluded that the cylinder block is driven by one tapered piston in a limited area and flue driving area is changed due to space angle of the tapered pistons and the swivel angle of the cylinder block. It is also observed that the force applied to tapered pistons increases as the discharge pressure and the rotational speed increase.     

The kinematic analysis of axial-piston pumps

This investigation describes the kinematics of axial hydraulic pumps with spherical ended pistons. The results, however, apply to the basic kinematics of all axial piston pumps. The current hypothesis is that sliding at the piston/swash plate interface contributes to the wear of these parts. The analysis concludes that sinusoidal sliding is inherent at the piston/swash plate contact point, and that its magnitude is a function of the pump design variables. Therefore, manipulation of the basic design variables of the pump is the key to controlling the amount of sliding and related wear at the contact point.     

Integrated slipper retainer mechanism to eliminate slipper wear in high-speed axial piston pumps

The power density of axial piston pumps can greatly benefit from increasing the speed level. However, traditional slippers in axial piston pumps are exposed to continuous sliding on the swash plate, suffering from serious wear at high rotational speeds. Therefore, this paper presents a new integrated slipper retainer mechanism for high-speed axial piston pumps, which can avoid direct contact between the slippers and the swash plate and thereby eliminate slipper wear under severe operating conditions. A lubrication model was developed for this specific slipper retainer mechanism, and experiments were carried out on a pump prototype operating at high rotational speed up to 10000 r/min. Experimental results qualitatively validated the theoretical model and confirmed the effectiveness of the new slipper design.