离心风机过桥轴承损坏分析与探讨

针对日常维修工作中经常发生的因轴承选取、安装不当等因素造成轴承游隙过小、甚至负游隙、导致轴承损坏的问题,通过一起离心风机烧损轴承事例,指出轴承安装后的有效游隙过小是轴承烧损的关键因素,并提出相应的解决方案。     

方钢管混凝土压弯构件可靠度分析

以方钢管混凝土压弯构件为研究对象,应用可靠度最优化方法,分析荷载偏心距为常量时构件可靠性。将偏心距视为基本随机变量,同时考虑轴向力和弯矩相关性影响下构件承载力的可靠性,得到相关结论。     

一种新型三极交流磁轴承原理与解耦控制

摘要：阐述了一种新型三极交流磁轴承的基本结构与工作原理,用等效磁路法推导了其悬浮力数学模型。针对三极交流磁轴承在两相静止坐标系下数学模型的强耦合特性,采用逆系统方法将其解耦为伪线性系统,并在该伪线性系统的基础上利用线性二次型调节器（Linear Quadratic Regulator,简称LQR）设计了满足性能指标的控制器。仿真试验表明这种解耦控制策略不仅能够实现三极交流磁轴承径向位移之间的动态解耦,而且可以实现转子稳定悬浮,并且系统具有良好的动、静态性能。     

6209轴承内套滚道剥落原因分析

通过常规金相检验方法分析了6209轴承内套滚道剥落的原因。结果表明：由于材料原始带状组织较为严重,引起带上与带间的碳、铬浓度的偏析,造成淬火组织和残余应力的分布不均匀并增加了基体脆性,导致了剥落。     

某型丝杠轴承的失效分析

通过对某失效丝杠轴承的分解检查,结合理论计算得知,运转过程中温升过大,致使丝杠伸长,增大了轴承载荷,从而导致丝杠轴承失效。依据丝杠轴承不同的工况及寿命要求,利用Bearinx软件分析其接触应力变化情况,给出了丝杠轴承合适的预拉伸量,并提出了相应的解决方案。     

基于虚拟仪器技术的炼钢转炉传动机构在线监测与故障诊断系统

目前,炼钢厂对炼钢转炉的传动机构--耳轴轴承的监测手段比较落后,定期更换耳轴轴承的方式也有不少弊端;虚拟仪器(Virtual Instruments)是计算机系统与仪器系统技术相结合的产物,最常用的开发平台为美国国家仪器公司(Natinal Instruments)的LabVIEW;开发了一套基于LabVIEW 7.1的炼钢转炉传动机构在线监测与故障诊断系统,该监测系统能够获取和记录耳轴轴承振动信号和轴心位移信号,在时域和频域进行全面分析,具有显示、报警、诊断分析和历史数据查询等功能;系统已在某钢厂投入试运行,效果良好.     

应用深层搅拌法处理素填土路基

简单介绍了深层搅拌法的原理、特性及施工工艺，结合工程实例，论述了用该方法处理素填土的设计方案，并对水泥搅拌桩的设计进行了分析，有效减少了总沉降量。     

常用石拱桥加固技术综述

根据目前大多数老石拱桥承载力普遍不足的现状,阐述了桥梁旧桥加固的迫切性,介绍了几种常见的石拱桥加固技术,详细指出了各自的优点,以恢复和提高旧桥的承载能力及通行能力,延长了其使用年限。     

数控机床误差的圆轨迹运动激光非接触测量新方法

对数控机床圆运动轨迹的测量是评价机床轮廓加工精度的有效方法之一。传统的测试设备如球杆仪很难实现在高进给速度下对小半径圆轨迹进行测量。本文介绍的利用激光多普勒位移测量仪可以在比较高的速度状态下、在半径从1mm到150mm范围内对数控机床的圆轨迹实现非接触测量，可获得数控机床的几何误差、反向间隙、伺服系统误差等，并能测得相应的圆半径、进给速度及加速度。本文主要论述采用这种新方法对数控机床伺服系统控制性能的优劣进行评价。     

Theoretical and experimental investigations of a variable- impedance hydrodynamic bearing

The aim of the work described in this paper is to develop a hydrodynamic bearing whose oil film dynamic stiffness and damping coefficients could be tuned to take on low values, without upsetting the bearing steady load carrying capacity, in order to obtain an improved dynamic response for machines running in such bearings. It was required that this tuning of the bearing dynamic characteristics could be carried out after assembly of the machine in question, and if necessary while the machine was in operation.A theoretical analysis of the new design of bearing was carried out, based on a finite-difference model of the bearing oil film. This analysis enabled the steady-state load carrying capacity of the bearing to be calculated for any particular running conditions. The oil film stiffness and damping characteristics were then calculated using the finite-displacement technique; these were then used to calculate the unbalance response of a flexible rotor running in such bearings. Experimental measurements of the unbalance response of a model rotor running in the new bearing design were also recorded, and compared with similar measurements obtained when conventional bearings were used.Both theoretical and experimental results show that the proposed new bearing design has a similar steady load carrying capacity to that of conventional hydrodynamic bearings, but that the unbalanced response and force transmissibility of machines running in the new design of bearing are substantially superior to that obtained with conventional bearings.