http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Transient EHL Analysis on Spur Gear Teeth with Consideration of Gear Kinematics
Koo, Young-Pil The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.8
Transient 3-dimensional elasto-hydrodynamic lubrication (EHL) analysis is performed on the contacting teeth surfaces of involute spur gears. Kinematics of the gear and the pinion are taken into account to get accurate geometric clearance around the EHL region of the contacting teeth. The surface pressure and film thickness distribution for the whole contact faces in a lubricated condition at several time steps are obtained through the analysis. Besides the pressure spike at the outlet region, a representative phenomenon in EHL regime, the pressure at the inlet region is slightly higher than that of the center region. The film thickness of transient condition is thicker than that of steady condition.
장시열 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.3
Hydrodynamic lubrication is simulated under the contact conditions that the direction of contact velocity reverses with a sudden high applied load in the contact of piston top ring and cylinder liner. Hydrodynamic lubrication film formation and pressure between piston ring and cylinder liner at the top dead center (TDC) location are investigated in detail because most friction loss and wear damage happen at this location due to the thin-film thickness resulting from the slow-down and reversal contact velocities as well as high applied load. The surface roughness on the cylinder liner by the honing process that is similar scale to the lubrication film thickness at TDC location is considered. Around the TDC location, laser surface textured (LST) surface that is larger scale than the surface roughness is designed for the favorable film formation. These two surface roughness parameters are simulated to study the effects of favorable film formation and less frictional loss of piston top ring at TDC location where most of damage and friction loss occur. Frictional power loss and minimum film thickness of the cylinder surfaces of the honed roughness are compared with those of patterned designs.
비정상 상태의 선접촉 탄성유체윤활 유막두께 및 유막압력 특성연구
장시열(Siyoul Jang),조재철(Jae Cheol Cho) 한국트라이볼로지학회 2009 한국윤활학회지(윤활학회지) Vol.25 No.5
Elastohydrodynamic lubrication (EHL) analysis shows that film thickness is very flat in the contact area and pressure distribution is somehow similar to that of Hertz ian contact pressure except the outlet region with pressure spike. These typical patterns of EHL film thickness and pressure are the cases under the steady contact conditions of applied loads and speeds. However, many engineering contacts are rather under the conditions of varying loads and contact speeds, and therefore the predictions for endurance life and performance of machine elements with steady EHL analysis are not suitable in many occasions. This study shows the differences in film thickness formation and pressure distribution between steady and transient contact conditions in several contact cases.