调心滚子轴承内圈位置样板设计探讨

对原有调心滚子位置样板方法进行了分析,并针对其不足提出了改进方法。     

特大型调心滚子硬车削工艺试验探究

以某型风电轴承用特大型调心滚子为试验对象,制定硬车削工艺流程,在高精密数控机床上进行硬车削工艺试验.通过对硬车削和传统磨削两种工艺加工产品检测数据进行对比分析,验证了特大型滚子采用硬车削工艺加工的优势和可行性.     

滚子轴承性能试验用外圈轴向定位工装设计

针对悬臂式轴承试验机,提出一种工艺装备的设计方案,重点解决圆柱滚子轴承外圈的轴向定位问题,以保证轴承试验的各种技术参数的高度模拟状态。     

An analysis of the lubrication mechanisms of the bush-type bearings in high pressure pumps

The paper examines the behaviour of the bushes in high pressure ‘bush configuration’ gear pumps. Experimental measurements of the clearances between the end-faces of the gears and the bushes are presented and an analysis of the mechanism of lubrication is given. It is suggested that bush lubrication depends on the surface irregularities at the ends of the gears and on the non-flatness of the bushes.     

A novel approach integrating dimensional analysis and neural networks for the detection of localized faults in roller bearings

The detection of the defective/worn out bearing components used in rotating machines is one of the main concerns in various applications. To improve the computational efficiency in the nonlinear dynamic analysis for the rolling contact bearings, a new methodology based on dimensional analysis (DA) theory is proposed in this paper. The developed model is used to predict the vibration responses due to artificially spalled bearing components to quantify the level of structural damages into these components. The use of a back propagation neural network (BPNN) has been made that also predicted responses from the network trained by developed algorithm using the experimental data obtained from the defective bearing components on the developed test rig. A comparison between the responses predicted by proposed DA method and the BPNN showed a fair amount of the agreement between the two approaches and validated the proposed model and proved outstanding tool for identification of spalled/damaged bearing components.     

基于加热炉步进机械滚轮和斜台面轨道的有限分析

针对步进机械升降滚轮和斜台面轨道,建立了利用平面应力理论分析得出的接触应力理论模型,以某加热炉步进机械为例,利用ABAQUS软件进行有限元分析对比验证了该理论模型和赫兹公式的差异,得出了滚轮与斜台面轨道间接触应力的分布情况。     

An analysis of the mechanisms of grease lubrication in rolling element bearings

There are over eighteen billion bearings in use in the world, and most are grease lubricated. Grease is chosen for a variety of reasons: it gives low friction, is easily confined, and has a long lubricating life at low cost. In many applications, the grease is expected to lubricate effectively over a wide range of conditions and for extended periods. For such applications, lubricant failure leads to instantaneous and rapidly increasing damage of the components and eventually breakdown. Thus, an improved understanding of the fundamental aspects of grease lubrication has far-ranging technical and economic implications. Despite the overwhelming importance of this subject, very little is known about the mechanisms of grease lubrication and the relationship between composition, lubrication performance, and life. This paper attempts to summarise current understanding of grease lubrication mechanisms in rolling element bearings and to consolidate the different aspects of this complex topic.     

弧面凸轮加工专用数控铣床设计

为重新开发和研制新一代加工弧面凸轮的专用数控铣床,通过对提出的加工弧面凸轮专用数控铣床的两种方案论证比较,选择了较为合理的方案。对有关技术难点,制定了相应的技术路线。以Y3180型滚齿机的床身、立柱为基件,以NT-XK5001专用数控铣床的设计理论为依据,完成了XK6030型弧面凸轮加工专用数控铣床的方案设计与结构设计。研究结果表明,该研究为进一步进行弧面凸轮加工优化设计奠定了基础。     

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance.     

I-DEAS在机构运动动画仿真中的应用

产品基于I-DEAS的建模完成后,继续直接地开发利用I-DEAS的功能实现产品的机构运动动画仿真,无须借助其他软件的帮助,从而降低了产品开发设计难度,减少了成本。     

Kinematic simulation of a parallel NC machine tool in the manufacturing process

Aimed at enhancing the research status of parallel machine tools, this paper introduces the structure of a 6-SPS parallel machine tool and explains the application significance of the kinematic simulation of the manufacturing process. The simulation software was developed in Microsoft Visual C++6.0 using OpenGL API functions. The data flows are presented. Finally, a simulation application of odd leaf hyperboloid is performed before the manufacturing process; the kinematic simulation demonstrates the rationale of trace planning and the feasibility of manufacturing instruction.     

喷嘴雾化流场数值仿真及结构改进研究

针对空气喷嘴形状对雾化性能影响的问题,对不同扇面结构参数下的空气喷嘴的雾化性能进行了研究,对空气喷嘴结构参数与雾化流场之间的规律进行了归纳,提出了一种空气喷嘴的结构模型,基于雷诺N-S方程与标准K-ε湍流模型以及标准壁面函数法,采用CFD方法对不同扇面孔数量及不同扇面锥角下的空气喷嘴的雾化性能进行了数值仿真,分析了空气喷嘴不同扇面参数的改变对雾化性能的影响,并通过搭建喷枪台架实验,对优选的结构模型进行了实验验证。研究结果表明,仿真结果与实验数据基本符合要求,改进后的空气喷嘴雾化性能得到了改善,为今后空气喷嘴结构的优化设计提供了一定的参考。     

注塑机用负载敏感变量泵控制系统的仿真研究

传统注塑机液压系统的能耗很大,用负载敏感变量泵控制系统实现泵出口处的流量和压力与负载所需的流量和压力相适应,有望提高系统效率.负载敏感变量泵控制系统设计并建模完成后,用MATLAB/SIMULINK软件进行仿真,分析了在负载流量压力均无变化、压力不变流量变化、压力流量均有变化三种情况下的仿真结果,并分析了系统在各种情况...     

An experimental investigation into the wear of the cylinder liner-piston ring in engines

In order to meet the demands of different engines, various kinds of material are used for the cylinder liners and piston rings. This paper describes a method and the results of wear tests for various liners and rings. These experiments were carried out on a FGM-1 wear simulation testing machine. The results help contribute to the rational selection and pairing of the liners and the rings.