吊车离合器修复一例

一台北京起重机器厂1999年生产的QY25D型轮式吊车行驶无力,车速不能随发动机转速升高而迅速提高。     

W4-60C型挖掘机新装离合器不分离的故障处理

有一台W4-60C型挖掘机,挂挡困难,当挂挡时,变速器齿轮明显有打齿的声音,不松离合器踏板,挖掘机就行走,油门跟不上总是熄火。这一现象属于典型的离合器分离不彻底。     

浅谈挖掘机液压油路系统的维护方法

针对挖掘机液压系统,根据实际经验总结了挖掘机液压系统维护的方法,主要阐述了液压油的更换工艺、步骤和注意事项,以保证挖掘机液压系统的安全、可靠,从而确保挖掘机的工作效率.     

主离合器分离不彻底故障的排除

离合器分离不彻底是指操纵杆或踏板处于分离位置时,其主动部分与从动部分摩擦力不能彻底消除,不能完全切断动力.离合器分离不彻底会使变速器换挡困难,产生齿牙撞击、齿端损坏,同时亦将加速压盘及摩擦片表面的磨损,引起离合器发热.     

工程机械离合器摩擦片的修复工艺

离合器是工程机械车辆的重要传动部件,也是最易损坏的组合件,当离合器摩擦片表面磨损严重、有裂纹、脱落、烧蚀严重、油污浸蚀严重时,则需更换摩擦片.更换新摩擦片常用的两种方法:一种是重新铆接修复工艺,另一种是粘接修复工艺.     

探讨三角高程测量代替二等水准测量的方法

根据高速铁路工程测量路线极长,沿线地形复杂多变,测量精度要求高的特点,提出了一种三角高程测量代替二等水准测量的方法,对高精度三角高程测量的严密公式及误差进行了分析,研究了TCRP1201全站仪复合对边测量原理、方法及其精度。     

火灾中铁路隧道衬砌温度场分析

以铁路隧道火灾为研究对象,采用ANSYS有限元分析的方法,对隧道衬砌温度分布进行了数值模拟研究。隧道火灾受热部位主要在隧道顶部,最高温度在1 000℃左右,火灾发生48 h后热量向山体扩散。隧道衬砌自然冷却到安全启封温度250℃以下需400 h以上。对隧道衬砌实施注水降温和通风散热是缩短启封时间的必要手段。     

Smart damper using sliding friction of aramid brake lining and self-centering of rubber springs

The purpose of this study is to develop a smart damper with flag-shaped behavior by using the sliding friction of aramid brake lining and the restoring capacity of pre-compressed rubber springs. For this purpose, the friction force of aramid brake lining pressed by bolts was used along with polyurethane rubbers, each with a length of 80 mm, a diameter of 95 mm, and a circular hole of 37 mm. In the experiments, loading frequency and torque force were considered. The loading frequency varied from 0.1 to 2.0 Hz, and frictional force was controlled by variable bolt torque force. The tests were conducted to demonstrate that the clamping force by the bolts could provide normal force to frictional material. The friction force by the aramid brake lining sliding was tested, followed by the pre-compressed rubber springs' behavior. Afterward, a damper combining the two components was tested to verify flag-shaped behavior by using a dynamic actuator, and the damping ratios were evaluated from the hysteretic curves. The behavior of the damper closely matched flag-shaped behavior, resulting in self-centering and energy dissipation capacity.     

有衬砌条件下隧道地下水渗流场变化规律研究

基于数值模拟方法,研究了隧道开挖后有衬砌支护情况下渗流场的变化及地下水位的变化情况,并分析了无衬砌条件下双孔隧道对渗流场的影响,得出了不同工况下孔隙水压力的变化情况及渗流场影响范围,并且得出了地下水位随时间的变化情况,可为隧道的设计、施工以及隧址区环境的保护提供参考。     

口孜东矿井壁浇筑温度场研究

以某主井为原型,通过模型的建立对井壁及壁后冻土温度场进行数值模拟,并详细分析了模拟结果,指出温度场控制是冻结法施工的关键,利用有限元数值模拟得出的相关结论可有效指导现场施工。     

影响现场测定锚口摩阻损失的常见问题

在桥梁预应力钢绞线张拉施工过程中,对锚口摩阻损失进行现场试验测定,并根据试验结果调整张拉力,是准确控制有效预应力的重要措施。准确测定现场锚口摩阻损失,以保证设计张拉力的准确施加,对确保工程质量具有重要意义。通过结合多起现场测定摩阻损失试验异常事例和经验,总结分析了影响现场测定锚口摩阻损失的常见问题并提出解决方案。     

Laboratory and field evaluation of asphalt pavement surface friction resistance

Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet-pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro-and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester (DFT), Circular Texture Meter (CTM), and Lock-Wheel Skid Trailer (LWST). The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.     

回转窑托轮现场加工及大小齿轮的更换施工

介绍了回转窑托轮经多年运行磨损后的现场表面切削加工方法及其大小齿轮的更换技术,切实保证了该抢修工程的工期和施工质量,对大型回转窑设备的抢修具有一定的借鉴作用.