Advanced Materials Research Vols. 479-481

Abstract: Abstract. Hydro-Mechanical Transmission (HMT) is a dual-power flow transmission system in which power is transferred parallel by mechanical transmission and hydraulic transmission. There are four types of HMT: torque-diffluence and torque-conflux, torque-diffluence and speed-conflux, speed-diffluence and speed-conflux, speed-diffluence and torque-conflux, when gear pair and planetary train are used as power diffluence or conflux mechanism respectively. And the result of kinematics characteristics analysis indicates that only torque-diffluence and speed-conflux type of HMT can be used as the vehicle transmission system because its output speed characteristics and pump speed characteristics can meet the requirements of the vehicle drive.

Abstract: In order to balance the force loading on the dowel pin , improve the load carrying capacity on pin-hole type output mechanism the FA cycloid drive, we considered to add uniform loading ring on the cantilever end of the pins in this paper. Under the action of uniform loading ring, we did the stress and deformation analysis on the dowel pin; Through the examples comparison we found that, the maximum bending stress of the dowel pin is reduced by 77.86% after adding the uniform loading ring, the dowel pin stress is well-distributed, and the bending strength of output mechanism is improved, thus the load carrying capacity of overall unit is improved.

Abstract: Based on the control principle with a constant engine speed, the coordination control process between engine and clutches during launching was analyzed. The maximum engaging speed of clutches and the maximum change rate of throttle were calculated with the maximum degree of jerk as the limited condition, and the control strategy of launch with two clutches was established. Genetic algorithm was used to optimize the distribution coefficient of torque between two clutches. The simulation results show that the control strategy of launch with two clutches using two clutches work together and the reasonable distribution of torque could be advantageous for clutches enduring life.

Abstract: Flexible structures with helical reinforcements are widely used in engineering because of their low bending stiffness and high strength. To strengthen the core, we focus on those structures which the helixes will contact the inner core loaded axial tension. The contact pressure between layers is taken into consideration and eliminated by using deformation compatibility equation. The pitch angle changes under axial tension which induces the geometric nonlinearity. The results were systematically compared with other researchers’ theory, which adopted more assumptions. Suggestions about the appropriate range of parameters are given, when assumptions can be used. The solution is validated with that obtained by both the finite element method and the classical solutions of two extreme cases.

Abstract: A practical method based on normal gaps topography is proposed here for loaded tooth contact analysis of WN gear having tooth surface deviations. The simulation of meshing state and tooth strength of WN gear are provided with real tooth surfaces. In the study normal gaps distribution is adopted to calculate tooth surface contact elastic deformation and local deviations due to manufacturing errors and tooth surface wear. For WN gear, the loaded distribution on the contact zone in meshing tooth surface has not been investigated because of their complexity in the contact state. The finite element method is adopted to analyze the contact pattern and tooth strength. The study has concretely calculated the contact pressure and zone of meshing in different loaded and transmission error. At the end examples are analyzed to demonstrate the effectiveness of the proposed method in quantifying effect of such deviations on the loaded distribution and tooth stress distribution.

Abstract: Water is a kind of low viscosity liquid and the bearing capacity of water lubrication bearings is very low. The influence factors of bearing capacity of water-lubricated thrust bearing and its improving methods are studied. First, bearing capacity characteristic of water-lubricated bearings is expounded. Secondly, the main factors of affecting bearing capacity are analyzed. At last, by combining the master pump motor running condition, the bearing capacity is improved by changing many factors including the material and hardness matching of friction pair, the roughness of grinding area, bearing structure, fan-shaped bushes number, pivot location, confined area of bearing, speed and the medium temperature, etc. The study provides a theory basis for improving bearing capacity of water-lubricated bearings.

Abstract: According to the principles of engagement and the mathematical model of non-circular gear tooth profile, the tooth profile of non-circular gear is draw. Then the three-dimensional model of the non-circular gear is created in Pro/E three-dimensional software to provide the basis for a non-circular gear motion analysis, dynamic analysis and finite element analysis.

Abstract: The new longitudinal seam pipe-type screen is designed, in order to avoid wire disorder and damage of wire wrapped the screen passes the bending zone in the heavy in dined well or horizorital well. The new longitudinal seam pipe-type screen cut outboard is narrow and the other is wide, so it is hard to be built up . It can clean by itself. it has high efficiency of sand control，equality gap，big circulation area，better corrosion resistance and longer service life. The application of slotted liner’s area of oil pass is bigger than the same specification’s application of slotted liner by four to seven times. The application of slotted liner holds true to extract oil in the horizontal and high-angle well which is the grains of sand’s diameter is bigger than the 0.15 to 0.3mm.The design of construction is up to the mustard construction under the well. It is safer and more reliable in the well completion.

Abstract: In the paper, Assessment and comparison analyses of fatigue strength for different axles of CRH2, CRH3 and CRH5 EMUs are conducted by applying the European standards and Japanese standards. The wheelset models of CRH2, CRH3 and CRH5 are set up by means of the finite element method. Static and fatigue strength of the axles are analyzed as well as the influence of the interference fit between wheel and axle on the contact pressure. To get accurate simulation of the dynamic loads on axles, mathematical models of CRH2, CRH3 and CRH5 EMUs are established by using the SIMPACK software, considering the nonlinearities in the EMU vehicle systems. The simulation is carried out according to the runtime table of the EMU in Beijing-Tianjin line. Stochastic irregularities of the track are considered in the dynamic simulation and the load history acted on wheelset is obtained. Based on the NSOFT software, the fatigue life of axles is predicted by applying appropriate fatigue life prediction methods.

Abstract: Markov prediction is an important method predicts availability of repairable system. How to estimate the transition matrix and profit matrix (if it has) play a fundamental role in Markov prediction. This article introduced briefly homogeneous Markov chain prediction method, study on estimation and algorithm which calculate the transition matrix and profit matrix accompany with transition on the base of historical data about system state and profit. Finally, according to algorithm, we write a customized functions utilizing R software and provide the calling method more details. It did fundamental work on utilizing data about system failure and maintenance to estimate the rate of system failure and the effective degree of steady-state, which enrich the theory and technology of decision models for reliability-centered maintenance and system maintainability modeling.