基于油液清洁度要求的滑靴油膜厚度设计

静压支承技术使滑靴在一定的油膜厚度下达到受力平衡,克服滑靴剩余压紧力设计法的不足。该文对滑靴油膜厚度的计算进行研究:首先,分析柱塞节流孔、油池压力及密封带节流共同组成的液压半桥的工作原理,得出液压半桥各设计参数与油膜厚度的关系;然后,考虑实际应用工况中油液的主要颗粒物堵塞节流孔的可能性以及污染物对滑靴磨损的影响,得出不同清洁度对滑靴油膜厚度设计的要求。最后总结出可适应于不同清洁度等级的滑靴油膜厚度计算方法。     

轴向柱塞泵滑靴静压支承的设计探讨

本文介绍的轴向柱塞泵滑靴静压支承,是用柱塞中心的阻尼管构成供油节流器的静压支承。文中分析了滑靴、阻尼管和静压支承的性能以及影响油膜厚度的因素,给出了滑靴性能随半径比α变化的关系曲线及支承性能随特性值β变化的关系曲线,并针对ZB-75泵的有关参数举例说明如何利用这些关系曲线进行滑靴静压支承的设计计算。     

水压柱塞泵滑靴中的短阻尼孔效应

尽管水的黏度很低，但是仍可通过选取合理的参数值设计出支承泄漏流量较小的滑靴静压支承。然而，为保证支承泄漏流量的合理设计值，必将以牺牲滑靴静压支承的刚度为代价。为此，该文提出利用滑靴中短阻尼孔的二次节流作用来解决这一矛盾，在确保支承泄漏流量较小的同时，也让支承刚度较大，从而大大提高滑靴的工作性能。     

新型静压平衡滑靴副及其在水液压泵中的应用研究

滑靴与斜盘摩擦副是柱塞泵的一对重要摩擦副，尤其是在水液压泵中，它的设计难度更大，文章在分析传统滑靴结构的基础上，提出了一种新型螺旋槽静压平衡滑靴，克服了静压支承滑靴易堵塞，难加工的缺点，可以有效改善水液压柱塞泵的滑靴寿命和可靠性。     

水压轴向柱塞泵的阶梯浅腔滑靴

为了改善水压轴向柱寒泵滑靴的静压支承性能，提出了一种利用动静压混合润滑的阶梯浅腔滑靴结构，并就其结构尺寸和支承性能与普通的滑靴结构型式进行了比较和相应的计算，发现其支承性能有所提高。     

径向柱塞泵中滑靴摩擦副的设计分析

该文介绍了静压支承工作原理，并利用静压支承原理对新型径向柱塞泵的滑靴结构进行了设计。分析了滑靴摩擦副的油膜刚度、漏损及影响油膜厚度的因素。     

柱塞泵滑靴常见问题分析及设计优化

通过对滑靴常见故障的分析，明确了损坏的原因是在工作过程中，支承滑靴正常工作的油膜受力不平衡遭到破坏所致，列举几种常见损坏现象，分析损坏原因，介绍了滑靴主要参数的计算及优化方法。     

一种新型滑靴静压支承在水压马达中的应用研究

针对水压传动的新特点 ,研制了一种新的同心圆缝型滑靴静压支承。分析了这种静压支承的工作原理和基本特性 ,介绍了一个设计实例和台架试验。试验表明 ,采用静压平衡法设计的同心圆缝阻尼型静压支承结构滑靴比采用剩余压紧力法设计的滑靴底部的磨损量小 ,接触比压小。这说明同心圆缝型滑靴静压支承结构特别适合水压马达     

水压滑靴副的润滑特性

为了提高水压滑靴副的抗倾覆能力,并且更加准确地认识其流动特性,提出了三腔独立支承的新型水压滑靴副结构,研究了其润滑特性比如抗倾覆能力和泄漏等。该结构采用独立阻尼和支承腔室的思路,通过独立刚度调节来增加滑靴副的抗倾覆能力。通过仿真计算与分析,对比了新型滑靴副和普通滑靴副的抗倾覆能力。同时, 综合考虑了水的流动惯性和表面粗糙度等因素,发现水压滑靴副水膜流场的流态可能为紊流,并不完全是纯层流状态,因此流态模型的差异将直接影响泄漏流量的计算结果,进一步影响到设计计算的准确性。研究结果为水压柱塞泵滑靴副的结构设计提供了一定的参考和更加准确的计算思路。     

轴向柱塞马达两种滑靴的性能研究

为了提高轴向柱塞马达滑靴的静压支承性能,提出了一种利用动静压混合润滑的斜面滑靴结构,并对其支承性能与普通的滑靴结构进行了比较,发现其支承性能有所提高.     

Tribological study on hydrostatic slipper bearing with annular orifice damper for water hydraulic axial piston motor

Hydrostatic slipper bearing is an effective way to maintain a fluid film between slipper pad and swash plate that slide against each other, and thereby mitigate direct surface-to-surface contact in water hydraulic axial piston motor (WHAPM). The hydrostatic slipper bearing with an annular orifice damper is proposed, and the reaction force of the bearing in WHAPM is investigated. The effects from the friction within the cylinder bore, the dynamics of the piston, and the centrifugal force of the piston–slipper assembly are examined. The characteristic equation of the hydrostatic slipper bearing with an annular orifice damper is formulated, where the effects of various geometric parameters (e.g. damping length, supporting length, and clearance between the piston and the cylinder bore) are reflected. The relevant criterion for designing the hydrostatic slipper bearing can then be established. Results of the theoretical analyses indicate that (a) the friction coefficient, the swash plate angle, and the inertia and centrifugal loads (generated under a high motor rotating speed) would have significant influences on the reaction force; (b) an appropriate swash plate angle can help eliminate the fluctuation of the reaction force; (c) the load-carrying capacity of the hydrostatic slipper bearing is more sensitive to the damping length than to the supporting length of the piston; (d) a short damping length can help enhance the load-carrying capacity; (e) a small clearance between the piston and the cylinder bore would help improve the adaptive ability to the varying load for the hydrostatic slipper bearing, when clearance between the slipper pad and the swash plate ranges from 5 to 20 μm. Experimental studies of the slipper pads sliding against the swash plates are conducted at a custom-manufactured test apparatus, given different material combinations and design methods. The experimental results indicate that the hydrostatic slipper bearing with an annular orifice damper would decrease the possibility of the severe wear between the slipper pad and the swash plate in comparison with the hydrostatic clamping ratio bearing in the WHAPM, and the CRA laser cladding (compared to the ZrO₂·MgO-plasma-sprayed coating and the stainless steel 2Cr13) is a promising candidate as the tribo-material when sliding against composite materials in water lubrication system. The hydrostatic slipper bearing with an annular orifice damper has been successfully applied to a WHAPM developed at the Huazhong University Science and Technology. The result demonstrates that the developed bearing has a satisfactory tribolgical performance, and can be extended to the manufacture of water hydraulic axial piston pumps.     

水压轴向柱塞泵滑靴静压支承中的惯性影响

在油压轴向柱塞泵的滑靴静压支承设计中,通常忽略Navier-Stockes方程中的惯性项,这是因为它较粘性项小得多,对计算结果的影响不大.然而,在水压轴向柱塞泵的研究中,由于水的粘度比油的粘度小得多,因此,惯性项就起着较大的作用.研究了水的流动惯性对支承间隙中的压力及流速分布的影响,从而对水压静压支承设计进行修正,得出更加合理的结果.     

润滑油含水量对轴承性能影响的试验研究

为研究润滑油含水量超标时轴承的运行性能,搭建了滑动轴承试验台,通过试验研究了在不同含水量的润滑油对滑动轴承温度、摩擦力矩及轴心运动轨迹的影响。试验发现,润滑油含水量较低(质量分数0. 5%以下)时对滑动轴承的温度、摩擦力矩和轴心轨迹影响不大,但含水量达到一定程度时(如超过质量分数0. 5%)会使轴心轨迹重复性变差,导致转子运转有不稳定的趋势出现。这表明润滑油含水会对滑动轴承运行性能造成一定的影响,更为准确的结果还需长期的实验验证。     

基于数值模拟的小孔节流空气静压轴承静动态特性研究

为了提高小孔节流空气静压轴承的静动态性能,基于流体力学和固体力学的基本控制方程,建立小孔节流空气静压轴承双向流固耦合数值模拟模型;采用静态数值模拟方法获取了设计参数对承载力和刚度的影响规律,进一步对微气膜间隙内三维流场特性进行了分析,有效降低了微气膜间隙内气体冗余现象对空气静压轴承动态稳定性的影响,并在数值计算的基础上对空气静压轴承结构和工作参数进行优化设计;在气体静压试验平台上对自行研制的空气静压轴承进行静动态特性测试。试验结果表明:所提出的数值模拟方法具有很好的预测效果;所采用的优化设计方法能够显著提升空气静压主轴的静动态特性。     

Numerical Analyses of Hydrodynamic Lubrication and Dynamics of the Rolling Piston and Crankshaft in a Rotary Compressor

In this article, numerical analyses of hydrodynamic lubrication and dynamics of the crank, rolling piston, and vane were carried out to study the tribological performance of a rotary compressor. Dimensionless Reynolds equations of journal and thrust bearings in dynamic load condition were derived and solved numerically. To deal with the lubrication of the rolling piston, the effect of the nonuniformity of tangential velocity over the bearing surface on the Reynolds equation was taken into account. In addition, combined with the analyses of dynamics and kinematics of the crank, piston, and vane, the angular velocities of the crank and piston as well as the motion mode between the piston and vane were studied. Analysis results illustrate characteristic oil film pressure distributions of the crank and piston bearings, which are different from that of common journal bearings. Under the influences of dynamic load and eccentricity of the cam, the wedge effect as well as the stretch and squeeze effect contribute greatly to hydrodynamic pressure. The relative motion mode between the piston and vane tip is not always pure sliding but accompanies rolling in some cases, which depends on the magnitude of the friction coefficient between the piston and vane tip. The analysis results are helpful for the improvement of rotary compressor design.     

Research on the anti‐sticking characteristics of water hydraulic piston friction pairs with hydrostatic bearing

Certain sticking phenomena generally exist in the common clearance sealing piston friction pairs. For oil media, it can be accepted because of its better lubrication, but for water media, it needs to be avoided as far as possible because of its worse lubrication. In this paper, the piston pairs with the hydrostatic bearing are presented to improve its anti‐sticking ability. The anti‐sticking performance is researched by computational fluid dynamics and experiment. The results indicate that the anti‐sticking ability can be improved for the new structure piston pairs. The key reason is that the hydrostatic bearing effect is reasonably applied. Copyright © 2012 John Wiley & Sons, Ltd.     

水液压柱塞泵中静压支承设计方法的理论研究

静压支承结构在水液压柱塞泵中起着重要作用,滑靴摩擦副和配流盘摩擦副是柱塞泵中典型的静压支承结构。目前静压支承的流场计算主要有两种方法,选择方法的依据主要是看哪种方法更加准确。不可压缩粘性流体的动量平衡方程(Naver-Stokes方程)是推导流场计算方法的基础,以此为依据进行严密的数学推演,可以得到与物理意义相吻合的流场设计方法。     

油水混合对径向滑动轴承润滑性能的影响

基于流体动压润滑基础理论,利用数值计算方法,在MATLAB软件中建立径向滑动轴承油水混合动压润滑的数学模型,对比分析润滑油中不同含水量对径向滑动轴承润滑性能的影响。结果表明:润滑油中混入少量的水对滑动轴承液膜的厚度和压力产生了一定的影响,最小液膜厚度随含水量的增加而减小,最大液膜压力随含水量的增加而增加;润滑油中混入少量水使得液膜合力和摩擦力变大,将不利于轴承的动压润滑,从而导致轴承润滑性能变差,并且加大轴承的摩擦磨损,降低径向滑动轴承的使用寿命。     

Characteristics of pressure and force considering friction in a closed cylinder with a holed piston

A mathematical model for a closed cylinder with a holed piston was established to investigate the operational characteristics of a gas spring. An ideal gas working fluid and an adiabatic process were assumed in the model. Simulation and experimental results for a typical design and operational condition showed good agreement. The model was then used to investigate the effects of the orifice diameter, the filling pressure, and the velocity of the piston on the applied force and operating pressures of two chambers in the gas spring. The results showed that the orifice diameter and the piston velocity had significant effects on the pressure difference between the two chambers. A 0.05-mm reduction in the orifice diameter led to an approximately two-fold increase in the pressure difference. A 10% increase in the piston velocity resulted in an approximately 25% increase in the pressure difference. The orifice diameter and the piston velocity had a greater effect on the chamber with lower pressure than on the chamber with higher pressure. The force applied to the piston also varied with the piston velocity, the orifice diameter, and the filling pressure due to irreversibilities including the throttling process through the orifice and friction between the wall and the piston. The present model and results are expected to supply useful information about a new gas spring design.