润滑方式对低速重载齿轮磨损性能的影响

本文探讨了处于边界润滑状态的低速重载齿轮的磨损机理。通过模拟实验，研究润滑方式对低速重载齿轮磨损性能的影响，得出了喷油润滑可减少低速重载齿轮磨损量的结论。     

齿面硬度对煤机低速重载齿轮磨损性能的影响

探讨了处于边界润滑状态的低速重载齿轮的磨损机理，通过模拟试验，研究了齿面硬度对低速重载齿轮磨损性能的影响，得出了提高齿面硬度可减少低速重载齿轮磨损量的结论。     

低速重载开式齿轮齿条传动润滑状态分析

采用三峡升船机齿条性能评定试验装置,研究低速重载、频繁换向条件下开式齿轮齿条的润滑状态。对开式齿轮齿条油膜厚度计算模型中润滑油的压黏系数进行修正以适用高黏度润滑油,利用油膜厚度准则对开式齿轮齿条的润滑状态进行分析。结果表明,采用油膜厚度准则能相对准确地判断低速重载开式齿轮齿条传动的润滑状态;转速、载荷对润滑状态有很大的影响,齿轮齿条换向时,润滑状况相对恶劣,易磨损、胶合,应尽量减小载荷和齿面粗糙度,增大润滑油黏度。     

低速重载齿轮齿条传动机构混合弹流润滑分析

低速重载齿轮齿条传动机构广泛应用于矿山、水利等升降系统中,但由于其工况恶劣,极易发生磨损、胶合。以三峡升船机的大模数齿轮齿条传动机构为研究对象,建立瞬态混合弹流润滑模型,分析了其啮合过程中的润滑状态,并研究转速、齿面线接触载荷以及齿面粗糙度对润滑状态的影响。结果表明:在一个啮合周期中,啮入点是低速重载齿轮齿条在啮合过程中的危险点;在低速、重载工况下,齿面线接触载荷对啮入点润滑状态几乎不产生影响,而齿轮转速与齿面粗糙度对啮入点膜厚比的影响显著;另外,粗糙度纹理方向也会影响齿面润滑状态,其中横向粗糙度纹理能够使齿面具备较大的膜厚比,改善其润滑状态。     

低速重载双圆弧齿轮跑合探讨

一、前言双圆弧齿轮目前广泛应用于各行业各种设备上,但国内对双圆弧齿轮尚处在研究阶段,且偏重于对高速重载双圆弧齿轮的研究,对低速重载齿轮研究更处于落后阶段。我厂在1983年首次成功地为广东省糖厂试制了输出扭矩高达1000kN·m 的大型同轴分流双圆弧齿轮减速器,质量较好。从实践中得知,要充     

提高低速重载齿轮副接触精度的几种方法

众所周知,低速重载齿轮副的主要功能为传递动力。为保证其使用性能,接触斑点是一个重要验收项目。如果齿轮副接触不好,重则造成齿轮早期失效,如严重点蚀、剥落,甚至断齿;轻则引起传动装置振动和噪声。对于低速重载齿轮行业来说,要解决这个问题是有一定难度的。一方面,低速重载齿轮要提高制造精度难度比别的齿轮行业更大,这不仅因为它们一般尺寸大,热处理变形大,且相应的机床、刀具、检测手段等国内条件也比较差。例如热处理变形控制,大规格高精度齿轮加工机床以及大规格精度测量仪等具体问题,一般工厂、企业解决起来都有困难:另一方面,即使单个齿轮的制造精度提高了,并不等于齿轮副的接触斑点就一定好,因为影响齿轮副接触斑点的因素确实很多,除了齿轮本身、轴承、箱体、装配,甚至材料性能都有关系。     

中硬齿面制造技术

本文论述了中硬齿面齿轮用于大型减(增)建齿轮和中、低速重载传动齿轮的优越性,并对中硬齿面齿轮的制造工艺和滚削刀具作了深入的探索。     

低速重载齿轮的磨损试验与研究

对圆周速度υ＝1～4m/s的齿轮传动进行了磨损试验。试验表明,υ＝1～4m/s低速重载齿轮均存在不同程度的齿面磨损,其磨损速率与圆周速度有关,且存在一最恶速度值,当齿轮处于最恶速度运动时磨损速率最大。对最恶速度现象进行了分析,认为边界润滑油膜仍具有一定的流变性,最恶速度现象与边界润滑油膜流变性形成的局部涡流有关。在试验条件下,最恶速度值为1.13～1.41m/s。为了提高齿轮的寿命,应避免齿轮在最恶速度及其附近运行。     

近十年来第二重型机器厂齿轮制造技术的进步

对我厂十多年来在低速重载齿轮制造技术方面所取得的进步与成就分类进行了综述。并对所制各种大型齿轮典型件及新增的主要切齿、检测设备附表作了介绍。     

高变位齿轮的修形研究

针对海洋钻井平台减速器高变位齿轮在低速重载工况中存在啮合冲击大、齿面容易胶合、传动噪音大的问题,选取了减速箱高速级一对齿轮副进行了分析建模,通过改变齿形参数对齿轮在抗胶合安全系数、轮齿啮合质量和传递误差进行了研究,提高了齿轮的传动质量,采用合理的修形参数和修形方法对齿轮各方面参数进行了研究和测试,最后对修形前、后齿轮强度等参数进行了对比分析。研究结果表明,通过合理的修形设计,能够改善齿轮啮合质量,提高齿轮的抗胶合能力,降低齿轮传动误差和噪声,这对低速重载齿轮修形在实际工程上的应用提供了参考依据。     

Experimental investigation on sliding and fretting wear of steam generator tube materials

In nuclear power steam generators, high flow rates can induce vibration of the tubes resulting in fretting wear damage due to contacts between the tubes and their supports. In this paper, the sliding and fretting wear tests were performed using Inconel 600HTMA and 690TT against STS 304, which are the steam generator tube materials. The sliding wear tests with a pin-on-disk type tribometer were carried out under various applied loads and sliding speeds at air environment. The fretting wear tests were carried out under various vibrating amplitudes and applied normal loads.

The result of sliding and fretting wear tests show that the heat-treated Inconel 690TT has better wear resistance than Inconel 600HTMA in air. The fretting wear regimes were plotted using the test results and the wear coefficient was calculated also. From the results, it was observed that the wear and tear by stick-slip has very strong effect on the fretting wear behavior.     

Accelerated wear testing as an aid to failure diagnosis and materials selection

The needs and advantages of accelerated wear testing are discussed, with particular reference to aerospace applications. Examples are given from recent work on plastics-based dry-bearing liners to illustrate how accelerated wear tests can provide information relevant to materials selection, identification of the main parameters influencing wear and definition of the relationships between wear, material composition and structure. Prediction of the service life of dry-bearing liners, however, presents problems and full-scale component tests are usually required     

金属切削中刀具月牙洼磨损模型的研究

刀具的前刀面月牙洼磨损和后刀面磨损在刀具磨损的研究中占据同等地位,但月牙洼磨损轮廓和刀屑交界面上的切削过程变量不易测量等因素,导致真正依据月牙洼磨损测试获取月牙洼磨损模型的研究非常少。基于硬质合金刀具切削低碳钢的月牙洼磨损实验,提出了一个经验磨损模型。该模型综合了黏结磨损和扩散磨损,考虑了刀屑交界面温度和压力对月牙洼磨损的影响。研究结果表明,该模型能够分析并预测相似切削条件下的月牙洼磨损轮廓。     

几种人字门底枢材料的摩擦磨损性能研究

通过摩擦磨损试验和摆动试验对比考察了几种人字门底枢材料在水润滑和脂润滑条件下摩擦磨损性能，并进行摩擦磨损机制分析，选出一种综合性能较好的材料，进行一些机械性能的测试，为下一步台架模拟试验作准备。研究表明：一种新材料FZ5（3）在摩擦磨损试验和摆动试验中都表现出优异的性能，通过硬度测量、拉伸性能等试验表明其具有优良的机械性能。     

Influence of test parameters on friction and wear results obtained in oscillating sliding tests with 100cr6 steel against sic‐based materials

In order to characterise materials for tribological applications, model tests with simple contact geometry are in widespread use. Friction and wear behaviour can be determined with high accuracy from this type of test. Tests with oscillating sliding motion have the advantage that only small‐sized specimens are required. However, the fact that the results of model tests are affected considerably by the choice of test parameters is often overlooked. In order to check the influence of test parameters on friction and wear results, tests were performed in which the relevant parameters (stroke, frequency, load, relative humidity of the surrounding air) were varied. Comparative studies with different SiC‐based materials (SiC, SiSiC, and SiC‐TiC) against steel (100Cr6) under unlubricated conditions at room temperature show that in all cases the relative humidity is an important parameter, influencing the friction and wear results substantially. Additionally, several parameters can modify friction and wear behaviour more or less significantly. The effects of test parameters on friction and wear are discussed here on the basis of the wear mechanism. Some of the consequences of this for planning test series and for the practical use of test results are noted.     

Correlation between the tribological behaviour and wear particle morphology—case of grey cast iron 250 versus Graphite and PTFE

Wear particles are produced as a result of interaction of two surfaces in mechanical systems. After extracting and separating particles by different techniques (filtration, ferrography …), their morphology, which is a function of the condition of tribological system (tribosystem), can be related directly to the wear process. In order to understand wear mechanisms, it is interesting to study the relationship between the characterization of wear particles (aspect ratio, shape factor, spike parameter) and the mechanical factors of wear. Therefore, a series of tests were conducted with polytetrafluoroethylene (PTFE) versus cast iron, and flake graphite versus cast iron. Wear particles were studied in a particular tribosystem to understand debris formation and wear. Consequently, after friction tests according to a plane on plane contact, wear particles were collected. After separation tests, particle morphology obtained through image analysis techniques, was used to determine how debris are produced and to elucidate wear mechanisms. Finally, we propose a wear mechanism with these particular tribosystems.     

Adhesive and abrasive wear behaviour of TiC alloyed,sintered, austenitic stainless steels

Abstract

This study examines abrasive and adhesive wear behaviour of austenitic stainless steel and its TiC alloyed composite produced through powder metallurgy technique. Abrasive wear tests have been carried out using a pin on disc wear tester under loads of 10, 20 and 30 N. For adhesive wear tests, a block on ring wear tester has been used under loads of 20, 40, 60 and 80 N. A possible correlation between the hardness, microstructure and wear behaviour of the samples has been investigated. The abrasive wear tests have revealed that the highest rate of mass loss occurred in the austenitic matrix stainless steel sample; also, mass losses decreased with an increased rate of reinforcing material in the composite. In adhesive wear tests, interparticle spacing developed from severe wear and extreme plastic deformation under heavy loads; however, at low loads, oxidation type wear was shown to be dominant.     

Tribological behavior of boundary lubricated sliding surfaces using three different spacing of surface profiles

The ball-on-disk type sliding tests with boundary lubricated steels were carried out to verity the effect of initial spacing in surface profiles on wear and scuffing. Three kinds of surface spacing, which are closely related with initial surface micro-cracks on sliding surfaces, were produced onAISI 1045 steel surfaces using different grinding and polishing processes. Frictional forces and time to scuffing were measured, and the shape and amount of wear particles were analyzed to compare the with original surface profiles. From the tests, it was confirmed that the size of wear particles are related closely to the original spacing of the surface profile. The time to failure and amount of wear were sensitive to the surface spacing. The wider surface spacing shows much longer sliding life and smaller amount of wear than the others. Time to scuffing was increased with increasing surface profile spacing. The size of wear particles increased while the wear and wear rateK were decreased with an increase in surface spacing. After the sliding tests, surface cracks of inner parts of the wear track formed due to scuffing were observed and compared among the specimens having the different surface spacing.     

Effect of varying load on wear resistance of carbon steel under unlubricated conditions

Pin-on-disk type wear tests of mild steel in contact with itself were conducted under unlubricated conditions in moist air to investigate the effect of changes in load on the transition behavior between severe and mild wear. Machines in operation are usually subjected to varying loads. In this study, two contact load levels were used as a simple varying load condition. The load was changed in a step-wise manner between the low and high levels either once or twice during certain tests.Severe wear appears at the high load levels and mild wear at the low load levels in wear tests under constant loading. After oxidized, work-hardened wear surfaces have been formed under mild wear at the low load during the first stage, the wear mode changes to “quasi-mild wear” having a low rate at the high load in the final stage. The load range, where the low wear rate can be maintained under quasi-mild wear, extends to the higher load level after the change(s) in load. Once the quasi-mild wear surface has been generated, the wear mode can be maintained even at the high load for a very long sliding distance.