Joo-Sup Jang

Shape Design Sensitivity Analysis Case of the Valves installed in the Hydraulic Driving Motor

ABSTRACTThis paper is about study how to decrese surge pressure that is occurred in excavator driving motor. We used computer simulation program SimulationX. It is also about the way finding design problem and approaching a solution through interpreting shape design sensitivity analysis. Programmes are below. First of all, finding shape fault by analyzing dynamic behavior of valves installed in hydraulic driving motor which is designed now. And drawing variable which is considered sensitive to improve dynamic efficiency among a lot of shape variables. Then, targeting that variable and examining dynamic efficiency stabilization tendency with controlling it. Finally, suggesting the most effective tuning method through variable combination as there are a lot of sensitive variables. Key words : Shape Design Sensitivity Analysis, Orifice, Flow Area, Piston Area, Surge Pressure, SimulationX요 약본 논문은 컴퓨터 해석프로그램인 SimulationX 를 이용하여 굴삭기 주행모터의 내부에서 발생하는 서지압력의 저감 방법에 대하여 분석하는 연구이다. 설계민감도 해석을 통하여 설계상의 문제점을 파악하고 해결책에 접근하는 방법을 다룬다 . 진행순서는 다음과 같다. 우선 현재 설계 된 주행모터에 장착된 밸브들의 동적거동을 분석하여 설계의 문제점을 찾아낸다 . 그 후 많은 설계변수들 중 동적성능향상에 민감하다고 판단되는 변수를 도출하고 설계치수를 조정하여 동적성능 안정화의 경향을 살펴 본다. 마지막으로 민감한 변수가 다수 일 경우 변수조합을 통해 효과적인 튜닝방법을 제안한다 .주요어 : 설계변수 민감도 해석, 오리피스, 개도면적, 수압면적, 서지압력, 시뮬레이션엑스

Performance Comparison Analysis of Frequency Sensing Shock Absorber and Passive Shock Absorber

Various forms of passive shock absorber have developed to supplement performance which is poorer than that of active shock absorber. It is called `Hybrid Conventional Damper (HCD)`. Frequency sensing shock absorber that this study will cover belongs to the HCD. This study aims to demonstrate that performance of frequency sensing shock absorber is superior than that of passive shock absorber. Study process is as follows. Firstly, analysis models for both passive shock absorber and frequency sensing shock absorber are developed to secure reliability. Then, elements which cause difference of ride quality are found out through comparison of hysteresis characteristics. By comparison of frequency characteristic, furthermore, damping principle of frequency sensing shock absorber is understood. Also, it determines if the absorber performs well even though maximum excitation speed is changed. Finally, the study proves that performance of frequency sensing shock absorber is superior than that of passive shock absorber after comparing change of damping power in excitation condition that various frequencies are mixed.

Lubricant flow analysis for effective lubrication of tractor forward/reverse clutch

Owing to the high power requirements of tractors, their low-power transmission gears often experience durability problems such as burning of the clutch. The operation of tractors under high load conditions also causes clutch slip, with the consequent longer operation duration exacerbating the burning of the friction plate. Solving this problem requires effective lubricant distribution. This was achieved in the present study by the development of an analysis model for predicting the lubricant flow rate. The reliability of the model was verified by comparing its predictions for various operation conditions with experimental measurements. Using the model, it was determined that effective distribution of the lubricant could be achieved without significant modification of the system, by only adjusting the gaps between the clutch piston and the housing, and between the separation plates and the case.

Developing Analysis Model for Evaluation of HCVT Materialization Possibility, and Examining It`s Characteristics

This paper reviews design validity before manufacturing HCVT prototype through simulation. The component part is being devided, modeled and checked if it works well to an designer`s original intent about some active modes. Also, the dynamic characteristic is examined how it changes according to alteration of pressure, friction and leak rate. Finally, HCVT design plan is being confirmed if it could be materialized through those analysis.

Development of Analysis Model of Pressure·Flow-controlled Swash Plate Type Pump for Evaluating Feasibility of Design

This study aims to verify the feasibility of design by developing pressure·flow-controlled swash plate type pump with the use of SimulationX, a computer analysis program. Developing analysis model based on design drawing data has a cost-saving effect because it is possible to figure out the effectiveness of design through the work and it never falls into repeated inaccuracies in the production process. Analysis model is developed in the following order. First, the structure of each part such as valve and rotating unit which have dynamic factor is analyzed and the modeling of single component is carried out, reflecting drawing data. Second, the modeling of pump assembly is carried out with the combination of each analysis model and a work is conducted to determine whether the modeling can perform pressure·flow control function according to load condition smoothly based on design intent. At the end of the modeling process, the feasibility of design is verified by showing the parts which are moving as expected mechanism.