C70型敞车车钩运用中存在的问题及改进建议

1存在的问题在运用中调查发现C70型敞车1位车钩不能正常分解,主要原因是钩提杆与滑轮托架相抵触,钩提杆无法向车体方向旋转,致使下锁销组成无法取下,给检修工作带来不便。2原因分析C70型敞车装用NSW型手制动机,经反复调查、测量、分析,滑轮托架焊装位置为:托架底部距端梁下平面190 mm、托架纵向中心线距1位下侧梁内平面994.5 mm处。钩提杆固定架焊装位置为:纵向中心     

气门旋转机构在柴油机上的应用

柴油机的进排气主要由气门的开闭来完成,气门设计的好坏直接影响到柴油机性能.因气门工作环境恶劣,所以对气门优化设计尤为重要.在气门的结构组件中,增加气门旋转机构,使气门均匀受热,减少气门与气门阀座密封面的积炭和磨损,防止漏气、卡死等现象,可提高气门与气门阀座的寿命.     

旋转自洁式空滤器固体颗粒的运动特性与性能分析

应用数值计算和试验的方法研究旋转自洁式空气滤清器固体颗粒的运动特性，采用Lagrange分析方法推导滤清器内颗粒的运动控制方程，在气相三维流场计算的基础上，计算了不同情况下的固体颗粒的运动轨迹以及分级效率。试验测试了不同几何参数下滤清器的滤清效率，计算与测试结果吻合良好。     

Kinetic characteristic for a synchronal rotary compressor

The synchronal rotary compressor is si mple instructure,but it has stronger adaptability for a vari-ety of working medium,so it is a good type as aircompressor,oil pump andrefrigerationsystemcom-pressor.The geometric theory and structure charac-teristics of this mechanis m are introduced[1].Itgives the designing background for the synchronalrotary compressor.The calculational methods of arotary speed of cylinder and relative speed bet weenthe cylinder and bladed rotor are deduced in detail;the…     

MODEL AND SIMULATION FOR A BRUSHLESS AC GENERATOR WITH AROTARY RECTIFIER

Objective For a brushless AC generator with a rotary rectifier, it is necessary and significant to model and simulate at normal and fault operation states. Methods Two new concepts, namely, Simulink signals and PSB (Power System Blockset) variables, are proposed, and the difference between the two concepts is clarified. Based on the new model for synchronous machines, a simulation model for a brushless AC generator with a rotary rectifier is constructed by Matlab/Simulink/PSB. This new model, which has a speed input terminal and an exciting voltage input one, can simulate the real electrical characters and direct mechanical connection between two synchronous machines perfectly. The rotary rectifier is a three-phase full-wave bridge rectifier which consists of six diodes. The model for the diodes is a macro-model which possesses much better accuracy than an ideal one of switches. Results Based on the present model, some simulation results such as exciting current waveform, phase current waveform and phase voltbge waveform are afftained at several operation conditions. Conclusion The simulation for a brushless AC generator with a rotary rectifier is demonstrated at normal and fault operation states, respectively. The results confirm the presented method.     

高性能沥青路面（Superpave）的技术初探

采用旋转压实新技术,用PG等级和常规指标评价SBS改性沥青的技术性能。从原材料、配合比设计、现场施工等方面简略介绍了Superpave技术在沪蓉高速公路成都段的首次应用,为今后Superpave技术推广应用提供借鉴。     

THE EDDY LOSSES OF A MAGNETIC THRUST BEARING

Accurate calculations of losses associated with the operation of magnetic bearings are particularly important for high speed applications where the rotor losses are expected to be large and for some particular applications where even low power losses will be critical. Power losses in the magnetic thrust bearing is often neglected, but if there is misaligned in the rotor and bearing, the magnetic field in the thrust bearing is no longer axisymmetric one, or the dynamic control current in the winding is time dependent one, eddy currents are caused to flow inside the conducting material, then the power losses are very important for magnetic bearing design. This paper presents an analytical model of a thrust magnetic bearing, and the magnetic fields, forces and losses of thrust magnetic bearing are calculated. In the calculations the frequency of dynamic control current is up to 1 000 Hz, rotating speed is from 60 rpm to 1 200 rpm, and the non-linearity of material is also taken into consideration. The results shows that if the magnetic field is not saturation, the eddy losses is proportional to dynamic control current frequency and a square function of dynamic control current, and also 5/2 power function of shafts speed.     

粉喷桩处理软土地基施工技术

粉喷桩加固软土地基的原理是：利用压缩空气携带着粉体固化材料，经过橡胶软管输送到钻头，借助叶片在旋转提升时产生的空隙喷出，喷出的混合气体在空隙中压力急剧降低，促使固化材料粘附在旋转叶片切开空隙的土中，地基土固化材料通过水泥的水解和水化作用、离子交换、硬化反应、碳化反应后，形成坚硬稳定的土体，从而达到加固软土地基的目的。其施工工艺流程见图1。     

磁浮轴承系统的数学模型与控制分析

磁浮轴是一种依赖电磁力支承转子的新型无接触轴承,与传统油润滑轴承相比,具有许多优越性。介绍了磁浮轴承的基本原理和结构,在建立磁浮轴承一对径向定位电磁铁单自由度数学模型的基础上,对该不稳定系统进行了ＰＩＤ补偿控制,研究了控制器参数对系统稳定性的影响。     

飞越谜雾

汽车，火车，轮船，飞机等高速交通工具的出现，它们给人类带来了现代的生活节奏，奔波于拥挤的大都市的人们在享受着现代科技带来的高速与高效率的同时，却在上天赐予的“雾”面前大都停止了前进，一意孤行却使生命在一刹那的碰撞之间可能化为乌有。