大吨位平板玻璃生产线上的双通道分流传输取片法

在堆垛周期小于玻璃切割周期的情况下,将堆垛辊道分为左右两部分,并且分别由两台伺服电机驱动,实现左右单独控制。以较小的投入及改造即可及时恢复堆垛辊道的容纳能力,使得玻璃物流连续而无需等待或滞纳,提高了堆垛机的效率和安全性。     

Performance of the Coned-Face End Seal with Regard to Energy Conservation

The effect of a face coning on seal performance, especially energy losses as indicated by a torque, were studied by comparing torque, face temperature, leakage, and wear of a conventional, widely used flat-face seal with three coned-face seals. Experimental evaluation was performed at rotation speeds to 8000 rpm, with pressures to 2758 kPa (400 psig), using a petroleum-base turbine oil. Axial movement of the mating seal parts was recorded using a digital data acquisition system. The height of the convergent-type cone on the face of the tungsten carbide primary ring ranged from 0.51 μm (20 μin) to 5.6 μm (220 μin) over the 3.175-mm to 6.36-mm (0.125-in to 0.25-in) face width. The torque of the coned-face seal, balanced lo 76.3 percent, was an average 42 percent lower, the leakage eleven limes higher than that of the standard flat-face seal. Reducing the balance to 51.3 percent by decreasing the face width of the coned-face seal resulted in lowering the torque by an additional 44 percent and increasing the leakage 12 to 230 times, depending on the seal shaft speed. No measurable wear was observed on the face of the coned seals. All four seals operated in the stable region of the stability map.     

Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes

A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. Metallurgical analyses show that the failure mode is associated with microstructural alterations manifested by white etching areas (WEAs) and white etching cracks (WECs). This article presents field experience from operating wind turbines that compares performance of through-hardened and carburized materials. It shows that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. In another comparison of two rotor bearings with different carburized metallurgies, one bearing developed WEA/WECs and failed by macropitting, whereas the other bearing did not develop WEAs or WECs and did not fail. The field experience shows that a carburized bearing that has a core with low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.     

On the Dynamics of Lubricated Cylindrical Roller Bearings,Part II: Linear and Nonlinear Vibration Analysis

This article is the second part of two companion papers. In the first article, curve-fitted relations of stiffness and damping coefficients of a single roller-to-race contact of lubricated roller bearings were developed. In the present work, these relations are applied to a rotor–bearing system. Two cases are studied to investigate the influence of lubricated cylindrical roller bearings on the vibration characteristics of the rotor system. In the first case, lubricated contacts are simulated as a linear spring–damper model. The overall stiffness and damping matrices are calculated by using the dynamic coefficients of individual load sharing rollers. These matrices are used in the finite element analysis of flexible rotor. In the second case, the nonlinear structural vibration of a lubricated cylindrical roller bearing is studied. Equations of motion of bearing elements are derived using the Lagrange equation. A nonlinear load–deflection contact model developed through the derived curve-fitted relations of dynamic coefficients is used in the equations of motion. Equations of motion are solved by a fourth-order Runge-Kutta integration method. The response of bearing elements under free vibration and due to rotating unbalance is studied for damped and undamped cases. Furthermore, results obtained using elastohydrodynamic finite and infinite contact theories are compared.     

拉伸机展平机构的设计与分析

对拉伸机展平机构的工作原理及结构进行分析。在此基础上设计出一款基于小滚架支撑的单滚展平机构,经过有限元分析,证明该展平机构所用大小辊子所受应力及产生的变形均能满足实际使用的要求。     

浅谈茂化水库混凝土防渗墙施工

施工方法正确与否关系到混凝土防渗墙的防渗效果。为此,结合茂化水库施工实践,从造孔、泥浆制备、墙体浇筑以及特殊情况处理等几个方面简要介绍了塑性混凝土防渗墙的施工工艺及方法。     

脱硫石膏配制胶结材和混凝土的研究

以脱硫石膏、水泥、石子、砂子、外加剂为原料配制胶结材和混凝土,并研究了所配制的胶结材和混凝土的性能。结果表明:脱硫石膏经过烘干、筛分后,与水泥、高效减水剂混合能够作为胶凝材料。用脱硫石膏替代10%水泥配制成胶砂,其抗压、抗折强度均满足P.O42.5水泥的强度指标要求,凝结时间及安定性合格;采用脱硫石膏替代30%水泥,添加减水剂配制成混凝土,其强度满足C30混凝土指标要求,抗渗性能达到P12抗渗等级要求。本研究结果如果能够实施,既可以大量利用脱硫石膏,又可以解决环境污染。     

人工假底假巷在中薄脉金矿中的应用

不断提高矿石的回采率,降低损失率,是矿山开采资源不断追求的技术革新目标。牟平腊子沟金矿近几年来,在尾砂充填采矿方法的基础上,以上人工假巷代替底矿柱、假底换顶矿柱等技术应用方面,取得了成熟的经验。特别在中薄厚石英脉型矿体开采中的应用,回采率有了较大的提高,安全技术措施可靠,施工工艺简单,投资节省,效益可观。     

含水率对受损混凝土超声波波速的影响

为了揭示含水率对受损混凝土的超声波波速的影响规律,研究了不同损伤程度的混凝土试块在不同含水率下的超声波波速。研究结果表明,含水率〈1．5％时,含水率对混凝土超声波波速的影响较小,可以忽略;含水率〉1．5％时,超声波波速随含水率的提高而明显增大;损伤越大,这种影响就越明显。     

径向柱塞式液压泵滚子运动学分析

对径向柱塞泵滚子进行了运动学分析,推导出了滚子的运行速度和角速度计算公式,并进行了仿真分析,指出滚子修缘和安装时,要确保定子和转子轴线相互平行,使得滚子和定子的偏压力角为零,以避免自旋的产生。