轴向柱塞泵配流副低速下摩擦磨损特性研究

发布时间：2018-05-14 10:26

本文选题：配流副 + 低速　；参考：《浙江大学》2017年硕士论文

【摘要】：轴向柱塞泵是液压传动系统的核心动力元件,它具有功率体积比大、结构紧凑、流量大、变量方便等诸多优势,在"上天、入地、下海"各领域如航空航天、工程机械、船舶海工等均有广泛应用。配流副是它最容易发生磨损和失效的三大摩擦副之一,尤其是在低速条件下完整油膜难以建立,配流副处于边界润滑状态,油膜不断产生和被破坏,始终处于动态的临界过程,直接影响到泵的低速效率、启动可靠性和寿命。因此,对轴向柱塞泵配流副低速下摩擦磨损/润滑特性及规律开展系统而深入的研究,对于进一步提高其效率、可靠性及寿命具有重要的工程和实际意义。表面形貌是指摩擦副表面的几何特征和性质,研究表明表面形貌对于混合润滑等状态下的摩擦、磨损和润滑起着重要影响。选择性激光熔融(SLM)快速成型技术可快速成型任意结构的零部件,为制造复杂结构产品、创新产品设计提供了高效的方法,特别适合单件、小批量液压元件的设计生产制造,可满足未来液压元件个性化的发展趋势。本文主要采用试验研究的方法,通过对轴向柱塞泵配流副工况分析及模型的简化(盘-环),在油润滑摩擦磨损试验台上进行实验,以研究表面形貌、激光熔融快速成型、工况和材料对配流副摩擦磨损特性的影响,并将摩擦系数、磨损率、温度、X射线衍射图谱、显微结构和表面/剖面形貌等作为主要评价指标。本文的主要研究结果如下:一、抛光的试件具有最低的摩擦系数和磨损率,它在试验过程中只发生了轻微的磨粒磨损且颗粒随油液排出未粘附到上试件表面;精磨试件的表面在试验后粘附了非常多细小的黄铜颗粒,发生了黄铜-黄铜的接触使得摩擦系数较高;粗磨试件的表面粘附了大块的颗粒使下试件产生了很高的磨损率,且由于局部区域更容易形成micro-EHL而具有较低的摩擦系数;织构化试件的微凹坑中积聚了很多黄铜颗粒,因而具有较高的摩擦系数和磨损率。二、SLM试件存在熔池、孔隙和晶粒细化等现象,经热处理的SLM试件熔池消失、硬度变大。当与黄铜配对时,SLM试件与传统制造(TP)试件相比具有更低的摩擦系数和磨损率;当与38CrMoAl配对时,SLM 316L与TP 316L在摩擦系数和磨损率上的差异较大,而经过热处理的SLM TC4比TP TC4具有更低的摩擦系数和磨损率。SLM试件中晶粒细化等结构影响其摩擦学性能,同时试件的塑性变形程度对其裂纹的形成和材料的剥落影响较大。三、随着转速的增加摩擦系数先增加并达到一极大值后逐渐减小,温度和磨损量的变化都是随着转速的增加而变大但磨损率随着转速的增加而趋于稳定。此外,随着转速的增加上试件表面球化孔直径变大,更易于储油和容屑且还出现了氧化层故有利于其摩擦系数的降低。
[Abstract]:Axial piston pump is the core power component of hydraulic transmission system. It has many advantages, such as large power volume ratio, compact structure, large flow rate, convenient variable and so on. Marine engineering and so on are widely used. The flow distribution pair is one of the three friction pairs that are most prone to wear and failure, especially the complete oil film is difficult to establish at low speed, the distribution pair is in the condition of boundary lubrication, the oil film is constantly produced and destroyed, and it is always in the dynamic critical process. It directly affects the low speed efficiency, startup reliability and life of the pump. Therefore, it is of great engineering and practical significance to study systematically and deeply the friction and wear / lubrication characteristics and rules of axial piston pump pair at low speed for further improving its efficiency, reliability and life. The surface morphology refers to the geometric characteristics and properties of the friction pair surface. The study shows that the surface morphology plays an important role in friction, wear and lubrication under the condition of mixed lubrication. The selective laser melting laser SLM (SLM) rapid prototyping technology can be used for the rapid prototyping of parts with arbitrary structure, which provides an efficient method for manufacturing complex structure products and innovative product design, especially suitable for the design, production and manufacture of single and small batch hydraulic components. It can meet the development trend of individuation of hydraulic components in the future. This paper mainly adopts the method of experimental study, through analyzing the working condition of the axial piston pump distribution pair and simplifying the model (disk-ring, the experiment is carried out on the oil lubricating friction and wear test bench, to study the surface morphology, laser melting rapid prototyping, The friction coefficient, wear rate, temperature X-ray diffraction pattern, microstructure and surface / profile morphology were taken as the main evaluation indexes. The main results of this paper are as follows: first, the polished specimen has the lowest friction coefficient and wear rate, and only slightly abrasive wear occurs during the test process and the particles are not adhered to the surface of the sample with oil discharge; The surface of the polished specimen adheres to a lot of fine brass particles after the test, resulting in a high friction coefficient due to the contact between brass and brass, while the surface of the rough-ground specimen adheres to a large piece of particles, which results in a high wear rate of the lower specimen. Due to the formation of micro-EHL in the local region, the friction coefficient is lower, and a large number of brass particles are accumulated in the micropits of the textured specimens, so the friction coefficient and wear rate are higher. The weld pool, pore size and grain refinement exist in the second SLM specimen. The hardness of the SLM specimen after heat treatment is increased with the disappearance of the weld pool. When paired with brass, the friction coefficient and wear rate of SLM316L and TP316L are lower than those of traditional 38CrMoAl, and the difference of friction coefficient and wear rate between SLM316L and TP316L is larger when paired with 38CrMoAl. However, the tribological properties of SLM TC4 treated by heat treatment are lower than that of TP TC4, such as grain refinement and so on. Meanwhile, the plastic deformation degree of the specimen has a great influence on the crack formation and the spalling of the material. Third, with the increase of rotational speed, the friction coefficient first increases and reaches a maximum value, then decreases gradually. The changes of temperature and wear amount are increased with the increase of rotational speed, but the wear rate tends to be stable with the increase of rotational speed. In addition, with the increase of rotational speed, the diameter of spheroidized holes on the surface of the specimens becomes larger, and it is easier to store oil and chip, and the oxidation layer is also found to be beneficial to the reduction of friction coefficient.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH137.51

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