Joong-Ho Shin

A Study on Optimal Wear Design for a Gerotor Pump

A disadvantage in the design of gerotor pump is a lack of parts that can be adjusted to compensate for wear in the rotor set, and as a consequence, it causes a sharp reduction of efficiency. In this paper, an attempt has been made to reduce the wear rate between the rotors of a gerotor pump. To do this, floating genetic algorithm (FGA) is used as an optimization technique for minimizing the wear rate proportional factor (WRPF). The result shows that the wear rate can be reduced considerably, e.g. approximately 8% in this paper, throughout the optimization using FGA.

Contact Surface Fatigue Life for RPG System

A roller pinion gear (RPG) system composed of either a pin or a roller and its conjugated cam gear can improve the gear endurance from that of a conventional gear system by reducing the sliding contact while increasing the rolling motion. In this paper, we first proposed the exact cam gear profile and the self-intersection condition obtained when the profile shift coefficient is introduced. Then, we investigated the Hertzian contact stresses and the load stress factors while the varying the shape design parameters to predict the gear surface fatigue life, which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

New shape design method of an epicycloidal gear for an epicycloid drive

This paper proposed a new approach to the shape design of an epicycloidal gear, which is a key part of an epicycloidal drive with a fixed outer ring. Applying the concept of instant center of velocity of a contact mechanism to the drive, this paper derived the analytical equation fot designing the epicycloidal plate gear, including the generation of curve conjugated to the pin-tooth of an outer ring and the calculation of transmission angles and determination of the contact points. This method has been completed by three steps: the first is to find the instant center of velocity for the epicycloidal drive; the second is to determinate the transmission angles and the contact points in the special coordinate systems; and the last is to generate the full shape of the epicycloidal gear by the coordinate transformation technique. A program for design automation of shape of the cycloidal gear has been developed with C++ language. Finally, an example was given to demonstrate the feasibility of the application.

Characteristics of Mechanical and Electrical Power Transmission for Small-Scaled Wind Turbine

Small-scaled wind turbine is converted to mechanical power of windmill to electric power by generator. However almost all studies seems to have overlooked converting relation of mechanical & electric power. It the reason for was very difficult establishing wind turbine system. In this paper, it is define equation of converting relation of mechanical & electric power. And it is verified by experimental methods. Defined equation will be used in developing electric devices such as inverter and controller in wind turbines. In addition this method can be used in the fields that utilize the rotational power into electrical power through generator.

Optimal wear design for a gerotor pump using genetic algorithm

A gerotor pump has various advantages such as compact size lower noise, less emissions and little pressure ripples for circulation of the fluid, but also it has a disadvantage without adjustable parts to compensate wear between the contact patch because of continuous contact during operation. Wear causes a sharp reduction of volumetric efficiency of pump. This paper presents the optimal design approach for a wear characteristic. It has been made to reduce the wear rate between the rotors of a gerotor pump. This paper uses genetic algorithm (GA) as an optimization technique for minimizing the wear rate proportional factor (WRPF). The results show that the wear rate can be reduced considerably, e.g. approximately 8%, respectively throughout the optimization using GA.

Optimization of Specific Film Thickness for a Disc Cam Using Genetic Algorithm

Abstract The rate of wear of cam followers in a valve train system is mainly a function of contact stress between the cam and the follower, sliding velocity and hydrodynamic film thickness between the two mating surfaces. The wear or surface fatigue can be reduced by maximizing the elastohydrodynamic film thickness. In this paper, an attempt has been made to estimate the optimal specific film thickness of cam-follower system quantitatively. A general TES polynomial function with real values of exponents is developed and genetic algorithm (GA) is used as optimization techniques for maximizing the minimum specific film thickness. The optimization programs enumerate values of the exponents for synthesis of cam displacement curves. The results show that the minimum film thickness can be increased considerably, e.g. approximately 7% in this paper. 1. 서 론 캠(cam)은 일반 링크 장치에 비해 구조가 간단하기 때문에 적은 부품수로 제작이 가능하고, 좁은 공간에서 다양한 운동을 얻을 수 있는 장점을 가지고 있다. 그리고 설계기술과 가공기술의 급속한 발전에 힘입어 그 활용범위가 점차 증가하고 있는 추세이다. 자동차 엔진의 밸브 트레인(valve train)용 캠의 경우 캠과 종동절(follower)간의 마찰이 엔진출력에 상당한 영향을 미치므로, 마찰을 최소화할 수 있는 윤활방식에 대한 연구가 활발히 진행되고 있다.