Abstract: Planetary gear train (PGT) with herringbone gears is one of typical transmission styles used in marine power transmission. How to effectively design a PGT with lighter structures and lower vibration and noise is a fatal task for heavily loaded marine gearing. An analysis system which was developed in the past decades is introduced in this paper to simulate the performance of planetary herringbone gear trains. The effects of main crucial parameters on the static and dynamic characteristics of planetary herringbone gear trains are studied by using the analysis system. The results are discussed and show that the presented system is effective and can be used in design of planetary herringbone gear trains.
Abstract: This paper performs analyses and studies to a part of the foreign advanced helicopter transmission system technology. It introduces the design train of thought, main component structures and relevant parameters. It will give a reference to engineering technical personnel of the helicopter transmission system.
Abstract: The average flow model proposed by Patir and Cheng offers a great convenience for the mixed-lubrication analysis of rough surfaces. The pressure flow factor introduced by Patir and Cheng helps to analyze the influence of roughness on the average pressure and average flow of a lubricant between surfaces. This paper reports how to reasonably choose initial pressure in computing the pressure flow factor. The numerical results show that the pressure distribution and further pressure flow factor value are sensitive to an initial pressure in solving the pressure flow factor, and the initial pressure of a constant value is not suitable for the pressure flow factor calculation for a measured surface with many sample points. Meanwhile, the pressure flow code is demonstrated by the comparison of the pressure obtained numerically with the analytical solution of pressure.
Abstract: In many gear transmissions the tooth load on one flank is significantly higher and is applied for longer periods of time than for the opposite one. An asymmetric tooth shape reflects this functional difference. This paper describes an approach to rationalize the asymmetric gears parameter selection to meet a variety of operating conditions and requirements to custom high performance gear drives.
Abstract: In this paper the failures which may occur in the development and service of the helicopter transmission system are discussed. The mode, characteristic, cause and corrective action for the failures are summarized. Besides, the measures of the design and manufacture to eliminate the failures are recommended.
Abstract: Due to those disadvantages of the cycloidal-pin wheel transmission, such as complex structure, low efficiency and low bearing capacity, a new kind of axis-fixed cycloid transmission is proposed. A new method for optimum modification quantity of cycloid gear is put forward on the ground of its drive principle. Considering the influence of modification to tooth contact stress, finite element model of tooth contact for the drive is built.The analysis result indicates that there is no obvious edge contact of tooth profile and it is more reasonable for the contact stress to distribute along tooth width. Load test on gear drive bench verifies the correctness of theoretical analysis.
Abstract: Gear dynamics model and 16-degree of freedom nonlinear vibration equations of the combining gear drive system are established considering backlash, transmission error and time-varying mesh stiffness, the equations are solved thanks to the fourth-order Runge-Kutta method, and the gear dynamic responses are analyzed, the vibration performances of this system affected by the dimensionless vibration frequency are investigated. The results show when the dimensionless frequency is 0.687, the system appears harmonic response; when the dimensionless frequency is 0.868, the system appears quasi-periodic response; when the dimensionless frequency is 0.889, the system appears chaos.
Abstract: On the base of reading up the latest overseas certification specifications and integrating the experience of engineering practice, the requirement for structure fatigue substantiation of helicopter transmission system was expounded, and the related key concepts were explained in detail. Furthermore, the general method for structure fatigue substantiation was presented. Thus, the frame of general principle for structure fatigue substantiation of helicopter transmission systems was basically founded.
Abstract: The Dry-type Dual Clutch system is designed for a certain Dual Clutch Transmission (DCT), and transient analysis is performed to investigate the thermal influence on driven plate in sophisticated slip conditions, which is determined by control strategy of DCT. First, a clutch engagement model is developed to obtain transient friction power corresponding to selected control strategy, and the distribution of time-varying heat flux is derived. On that basis, the thermal effects on the driven plate are simulated by finite element method. Finally, the temperature and thermal stress distributions on the frictional surfaces are acquired, which shows that the previously designed clutch system agrees with thermo requirements. This new approach which is more superior to the traditional clutch analysis, can adjust to different control strategies, thus it can be applied to facilitate the thermo analysis and practical design of DCT system.
Abstract: This paper makes the emulate experimental research of cutting force in high-speed dry gear milling by flying cutter with finite element analysis method by using the established cutting force model yet, makes the comparative analysis for the result of simulation experiment and theoretical calculation, verifies the correctness of cutting force model and calculation method, makes the comparative analysis for the influencing relations and changing laws of cutting force and cutting parameters and so many factors, and reveals the cutting mechanism of high-speed dry gear milling by flying cutter initially. By the research of this paper, it provides basic theory for subsequent cutting machine technology of high-speed dry gear hobbing, and establishes the theoretical basis for the spread and exploitation of this technology.