질소이온코팅 SCM415강의 마찰ㆍ마모특성에 관한 연구

류성기(Sungki Lyu),하휘파(HuiBo He),이상현(Sanghyun Lee),이동규(Donggyu Lee),손유선(Yusun Son) 한국생산제조학회 2006 한국생산제조시스템학회 학술발표대회 논문집 Vol.2006 No.5

SCM415 alloy was implanted with nitrogen ions using plasma source ion implantation(PSII), at a dose range of 1×10 to 6×10¹?N?㎝?². Auger electron spectrometry(AES) was used to investigate the depth profile of the implanted layer. Friction and wear tests were carried out on a block-on-ring wear tester. Scanning electron microscopy(SEM) was used to observe the micro-morphology of the worn surface. The results revealed that after being implanted with nitrogen ions, the frictional coefficient of the surface layer decreased, and the wear resistance increased with the nitrogen dose. The tribological mechanism was mainly adhesive, and the adhesive wear tended to become weaker oxidative wear with the increase in the nitrogen dose. The effects were mainly attributed to the formation of a hard nitride precipitate and a supersaturated solid solution of nitrogen in the surface layer.

질소이온코팅 SCM415강의 마찰ㆍ마모특성에 관한 연구

류성기(Sungki Lyu),하휘파(HuiBo He),이상현(Sanghyun Lee),이동규(Donggyu Lee),손유선(Yusun Son) 한국생산제조학회 2006 한국공작기계학회 춘계학술대회논문집 Vol.2006 No.-

SCM415 alloy was implanted with nitrogen ions using plasma source ion implantation(PSII), at a dose range of 1×10 to 6×10¹?N?㎝?². Auger electron spectrometry(AES) was used to investigate the depth profile of the implanted layer. Friction and wear tests were carried out on a block-on-ring wear tester. Scanning electron microscopy(SEM) was used to observe the micro-morphology of the worn surface. The results revealed that after being implanted with nitrogen ions, the frictional coefficient of the surface layer decreased, and the wear resistance increased with the nitrogen dose. The tribological mechanism was mainly adhesive, and the adhesive wear tended to become weaker oxidative wear with the increase in the nitrogen dose. The effects were mainly attributed to the formation of a hard nitride precipitate and a supersaturated solid solution of nitrogen in the surface layer.

공구유닛 구동기어의 치형 최적설계에 관한 연구

류성기(Sungki Lyu),김동선(Dongseon Kim),백권인(Gwon-In Baek),진진(Zhen Qin) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11

The Study on the Analytical Prediction of Bearing Life and Load Distribution for Plugin HEV

Qi Zhang(장기),Zhezhu Xu(허철수),Sungki Lyu(류성기) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5

The transportation is almost dependent on a single fuel petroleum with transportation energy dilemma. Hybrid Electric Vehicle(HEV) technology holds more advantages on efficiency improvements for petroleum consumption at the transportation. And bearing is recognized as the important component of gearbox. Gearboxes for HEV transmission have been ensured the highest reliability over some years in withstanding high dynamic loads. At the same time, the demands of lilghweight design and cost minimization are required by thought-out design, high-quality material, superior production quality and maintenance. In order to design a reliable and lightweight gearbox, it is necessary to analyze bearing rating life methods between standard and different bearing companies with calculation methods for modification factors. In this paper, the influence of life time of bearings will be pointed out. Bearing contact stress and load stress distribution of HEV gearbox are obtained and compared with Romaxdesigner and BearinX. And the unequal wear of the left bearing for the gearbox internediate shaft is investigated between simulation and test.

Design and Structural Stability Investigation of Novel Flat-Face Multi-coupling Systems for Hydraulic Power Equipment

Zhen Qin,Xiaoran Tang,Yu-Ting Wu,Sungki Lyu,Sang-Hu Park 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.10

Hydraulic power transmission systems have been widely used in recent years by virtue of their precise transmission, large driving force, safety, and reliability. Designs of hydraulic systems are being proposed that provide more convenient installation, greater driving force, and are more environmentally friendly. With this evolution, traditional hydraulic couplings are gradually becoming unable to meet the ever-changing hydraulic circuit connection requirements. In this paper, based on the fluid-structure interaction numerical investigation method and experimental verification methods, the construction safety and stability of the novel flat-face coupling system (NFFCS) is investigated, and the safety level of its construction stability is compared with that of a conventional flat-face coupling system. In addition, the mechanism design for 4-circuit and 6-circuit hydraulic quick coupling equipment based on the NFFCS technology is proposed, and the kinematic principles of its rapid and safe connection are explained. A series of structural stability simulations are implemented and the safety and reliability are discussed.

The Calculation and Experiment for Measurements over Pins of the External Helical Gears with an Odd Number of Teeth

Zhang, Qi,Kang, Jaihwa,Li, Qing,Lyu, SungKi 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.12

For the calculation and measurement between pins in the external helical gears with an odd number of teeth, they have been studied for many years. And the calculation methods and measurements are also described in DIN and AGMA standards. However, for ISO standard, a clear conclusion has not been given yet. The differences between the research results and standards are still inconsistent in some cases of the actual situation. In the actual measurements, the pin instead of the ball is always used by survey crew. It is unreasonable that an incorrect value (usually the value across the ball) and measuring methods are used. In this paper, different calculations and measuring methods of different standards are firstly expressed. For different measurement tools, like dial caliper, outside micrometer and disc micrometer, the measurement results are not the same. Therefore, two test gears were manufactured and analyzed to verify the accuracy and reliability of the measurement methods between software calculation and manual measurement over pins. It is found that the calculation and measurement methods of DIN, AGMA or similar methods are feasible and reliable, but for the measuring surface of the measuring tools, the pin should be in a steady state along the spiral groove. Reliable measurement values are obtained to ensure the accuracy of the measurement. It is helpful to understand the measurements of the standard or similar methods through theoretical analysis and experiments.

The Evaluation of Contact Fatigue Strength for 20MnCr5 Carburized Gear

Zhang, Qi,Zhang, Jing,Wu, Changhong,Xu, Zhezhu,Lyu, SungKi 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.1

A FZG test rig for determining the contact fatigue characteristics of gear teeth was used in this paper. Under the range of operating conditions, experiments were performed by using standard spur gear test specimens which were made from 20MnCr5 gear alloy steel. Test rig, spur gear test specimens, the properties of the gear material were also introduced as well as the method to determine the stress levels. After the test, a small spalling pitting phenomenon was observed in the vicinity of the test pinion pitch line which is close to the gear tooth root portion. The tooth is subjected to the highest load due to the single tooth pair contact. The test data was analyzed and processed by statistical methods, and the equation parameters of gear contact fatigue and the contact fatigue limit were obtained. The analyzed results showed that the three-parameter Weibull distribution was best to fit the given stress for the contact fatigue life of 20MnCr5 carburized gear with better precision and adaptability. Finally, the P-S-N (Probability-Stress-Life) curves for the contact fatigue strength had been obtained by the reliability theory. It would provide a reliable basis for the reliability design for 20MnCr5 carburized gear fatigue life.

Static Load Analysis of Twin-screw Kneaders

Jing Wei,Guang-Hui Zhang,Qi Zhang,Junseong Kim,SungKi Lyu 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.3

A static load analysis of twin-screw kneaders is required not only for the dynamic analysis, but also because it is the basis of the stiffness and strength calculations that are essential for the design of bearings. In this paper, the static loads of twin-screw kneaders are analyzed, and a mathematical model of the force and torque moments is presented using a numerical integration method based on differential geometry theory. The calculations of the force and torque moments of the twin-screw kneader are given. The results show that the Mx and My components of the fluid resistance torque of the rotors change periodically in each rotation cycle, but the Mz component remains constant. The axis forces Fz in the female and male rotors are also constant. The static load calculated by the proposed method tends to be conservative compared to traditional methods. The proposed method not only meets the static load analysis requirements for twin-screw kneaders, but can also be used as a static load analysis method for screw pumps and screw compressors.

치형수정에 의한 기어의 최적설계에 관한 연구

손유선(Yusun Son),황규석(Guesec Hwang),탁성훈(Seonghun Tak),류성기(Sungki Lyu) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

This study deals with the TE(Transmission Error) of gear tooth profile by modifying a profile and lead of a surface of tooth. First, we experimentally confirmed that the TE is a synthesis of the sliding velocity between both gears. Since various types of TE appear in the experiments, we introduced definition of transmission error and the optimism design by modifying a surface parameters. The test stand's performance is then evaluated through a series of multiple torque transmission error tests. Comparisons are made between data recorded before and after the test stand's redesign, and subsequently repeatability studies are performed to verify the veracity of the measured data. Finally, the experimental results are compared to the analytical predictions of two different gear analysis programs.

Experimental Application of Pitting Formation for 20MnCr5 Carburized Gear Tooth

Zhang, Jing,Zhang, Qi,Wu, Changhong,Xu, Zhezhu,Lyu, SungKi 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.5

Gear tooth contact analysis and a FZG gear test rig were applied to study and analyze gear contact fatigue in this paper. Under the range of operating conditions, experiments were performed in the test rig by using standard FZG type C spur gear test specimens which were made from 20MnCr5 gear steel. Test rig, spur gear test specimens, the properties of the gear material were also introduced. After the test, pitting formation was investigated using scanning electron microscopy. Two kinds of fatigue spallings caused by subsurface fatigue failure and surface fatigue failure were investigated. And energy spectral analysis for two kinds of fatigue positions were analyzed by the EDS detector, the materials of subsurface fatigue failure are the oxide $Al_2O_3$ and the carbide, and the black textures of surface fatigue failure are the oxide and the non-martensitic material. Through the mechanism analysis of this gear contact fatigue failure, it is founded that reducing the oxygen content in the material, can effectively reduce the oxide inclusions in the steel. It would provide a reliable reference study for 20MnCr5 carburized gear.