Development of Rubber Damper of Flywheel for Diesel Engine

디젤기관(機關) 플라이휠의 고무댐퍼 개발(開發)

Data acquisition system and computer program developed in this study could be well used in engine vibration analysis. The system and program developed were also operated to be able to control measuring interval, number of channels, number of data. The flywheel was specially studied to provide the proper weight with rubber damper for the engine design at low level of vibration. This study was conducted to obtain basic data which affect the engine vibration. The experiment of this study was performed on original weight flywheel, weight-reduced flywheel, weight-reduced and rubber-coated flywheel, weight-reduced and damper-attached flywheel. Avarage of peak value, maximum vibration, power spectrum density based on FFT analysis are major factors of this experiment. Results were obtained as follows : 1. When rubber was inserted in the flywheel rim of which weight was reduced from 32.2kgf to 24.4kgf, maximum vibration of the engine was decreased 48.3% at X axis, 35.5% at Y axis and 34.6% at Z axis in comparison with the flywheel of original weight. 2. When the flywheel of rubber damper was compared with the original flywheel, the average of absolute vibration for rubber damped flywheel was decreased at X, Y, Z axis and especially its decreasing rate was so high at X-axis comparing with the other flywheel, which implied that rubber damper was very useful to reducing the vibration of the engine at X axis. 3. Hysteresis losses of X, Y, Z axis were greatly decreased in the flywheel with rubber damper on rim. 4. Damped oscillation effect on X and Y axis vibration above average peak vibration by the flywheel of rubber damper on rim was larger than those by the other flywheels. 5. Power spectrums of vibration at real and imaginery part were bi-mode type. The vibration frequency of rubber dampered flywheel which weight is decreased was slightly increased as compared with original flywheel.

본(本) 실험(實驗)은 개발(開發)한 시스템과 분석(分析) 프로그램을 이용(利用)하여 플라이휠의 형태별(型態別)로 진동량변화(振動量變化)를 분석(分析)하였다. 플라이휠의 형태(型態)는 원래(元來)의 것과 중량(重量)을 8kgf감소(減少)시킨것, 그리고 중량(重量)을 감소(減少)시키고 립부(部)의 외부(外部)와 중간(中間)에 고무댐퍼를 부착(附着)시킨 것으로 각각(各各)의 진동량변화(振動量變化), PAV율(率), 최대진동량(最大振動量), FFT 등(等)을 분석(分析)하여 비교(比較)하였으며 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 최대진동량(最大振動量)은 플라이훨 중간(中間)에 고무댐퍼를 부간(附看)한 것이 원래(元來)의 플라이휠에 비(比)하여 X축(軸) 방향(方向)은 48.3%, Y축(軸) 방향(方向)은 35.5% 그리고 Z축(軸) 방향(方向)으로는 34.6% 감소(減少)된 것으로 나타났다. 2. 절대진동량(絶對振動量)의 평균(平均)은 모든 공시(供試)플라이휠에서 부하(負荷)의 증가(增加)에 따라 감소(減少)하는 경향(傾向)이었으며 플라이휠의 림 중간(中間)에 고무댐퍼를 부착(附着)하는 것이 원래(元來)의 플라이휠보다 X축(軸) 방향(方向)은 46.7%, Y축(軸) 방향(方向)은 11.5% 그리고 Z축(軸) 방향(方向)에서는 7.1%가 감소(減少)되어 X축(軸) 방향(方向)의 진동감소(振動減少)는 고무댐퍼의 효과(效果)가 매우 높은 것으로 나타났다. 3. 히스테리시스 손실(損失)은 고무댐퍼를 림 중간(中間)에 부착(附着)한 플라이휠의 X축(軸) 방향(方向)에서 크게 감소(減少)하는 경향(傾向)으로 나타났다. 4. 피크진동량(振動量)의 평균(平均)보다 큰 X, Y축(軸) 방향(方向)의 진동(振動)은 고무댐퍼를 림 중간(中間)에 부착(附着)한 플라이휠에서 감쇠효과(減衰效果)가 크게 나타났다. 5. Power spectrum 분석결과(分析結果)는 실수부(實數部), 허수부(虛數部) 모두에서 가우슨분포곡선(分布曲線)과 일치(一致)하지 않는 bi-mode형태(形態)인 것으로 나타났다. 진동(振動)의 주파수(周波數)는 원래(元來)의 플라이휠은 43.2Hz이고 그외의 경우에서는 49Hz로 약간(若干) 증가(增加)하였다.