CONCEPTUAL DESIGN OF ECONOMIC HYBRID VEHICLE SYSTEMUSING CLUTCHLESS GEARED SMART TRANSMISSION

윤용산,S. J. Kim,김경수 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.5

Most hybrid vehicles employ the continuously variable transmission (CVT or eCVT) currently as their choiceof the transmissions. Recently, an automated geared transmission (AGT) or dual clutch transmission (DCT) is being tried forsome hybrid vehicles for the better fuel economy than the CVT hybrid. However, this AGT or DCT is using automatedclutches which require the hydraulic power in addition to the slippage in the clutch plate invoking some energy loss as wellas wear. Also, they require a motor with significant power to match to the engine power. The clutchless geared smarttransmission (CGST) has no clutch and the clutch function is performed by a planetary gear system controlled by a motor-generator. The hybrid vehicles proposed here using CGST may have some merits in durability, fuel efficiency, and cost sincethey do not have clutches. The motor used for the clutch function can be also working for power merge with the engine inpropelling the vehicle. The proposed hybrid system can be either mild hybrid or full hybrid by adopting a different capacityof battery with much smaller motor-generator due to the planetary gear system compared to the other type hybrid vehicles. Inthis study, the prospects of newly proposed CGST hybrid system are examined in practical aspects compared with AGT hybridor DCT hybrid systems.

하이브리드 커빅 기어 최적설계 및 IRT기법을 적용한 건정성 평가

이경일 ( Gyung-il Lee ),정윤수 ( Yoon-soo Jung ),김재열 ( Jae-yeol Kim ) 조선대학교 공학기술연구원 2016 공학기술논문지 Vol.9 No.4

The gear has played the important roles for long time as the one of representative mechanical elements together with bearing and screw since the industrial society. The gear not only plays the role of transmitting the power and is widely used as the one for the wrist watches in small size and turbine reduction gear for vessel in thousands of kw class, reduction device in automobile and aircraft, differential gear and wind power generator in large size but also its kind and usage are various even today. The gear that is developed in such various ways is developed to carry out the complex operations and its research and development are carried out in various types. The gear with such complex operations, special generation and shape is called as hybrid gear and its development is being carried out by the companies and academic society actively. Among these gears, hybrid CURVIC gear is an index of precision in machine tools in industrial society. In this paper, we prove the applicability and reliability of FEM analysis and infrared radiography for reliability improvement in hybrid CURVIC gear.

Optimum interface shape and vibration test for a new transmission helical gear composed of steel and aramid/phenol composite

심은영,김철,곽기석,Bongjoon Kim 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

Hybrid gears made of fiber-reinforced polymeric composite material and steel are recently attracting electric vehicle designers’ attention due to their possible advantages such as lightweight and reduced vibration transfer for automotive transmissions. In this study, polymeric composite material is placed in-between the steel teeth and a central hub region in the radial direction of the hybrid helical gear. The partial usage of polymeric composite material for the high torque gear is expected to reduce the transmissibility of vibration from teeth to hub as well as the weight of a transmission gear-train. Using the finite element method, optimization, and vibration tests, a composite hybrid helical gear satisfying strength and vibration characteristics is successfully developed in this study. The reduction in acceleration of the hybrid gear is observed by comparing to that of a 100 % steel gear. From a point of view in damping ratio, the composite hybrid gear can make reduction of vibration by 42.3 %. To secure the bonding strength between steel and composite parts, the design optimization for the complicated bulgy and hollow interface region is performed by considering complex dimensions.

CGST의 구조적 다양성 및 동역학 시뮬레이션을 통한 변속 특성 분석

김선제(Sun Je Kim),송치웅(Chiwoong Song),김경수(Kyung-Soo Kim),윤용산(Yong-San Yoon) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

Existing clutched automotive transmissions have problems with wear of disc pad caused by thermal stresses in frictional disc, need of hydraulic equipment, and degradation of longitudinal drivability by instantaneous disconnection of power delivery during shifting gears. Recently, to address the difficulties with the clutches we proposed the novel hybrid capable transmission system so-called clutchless geared smart transmission(CGST), which uses a planetary gear system and an electric motor instead of a clutch. The CGST can be divided into various structures according to the order of arrangement and connections between shafts. In this research, we propose two types of representative structure of CGST(named TP, PT type) and analyze the operational characteristics during shifting gears to suggest the standards for design. First of all, the dynamic models of CGST structures are developed in MATLAB/Simulink environment. Simulation results show that two CGST types have different motor dynamics during shifting gears by arrangement of a planetary gear system and a multiple-input gear-train. In TP type of CGST, as the power from the engine is transferred to the planetary gear system through multiple-input gear-train, the input torque is magnified and the speed is reduced by a gear mesh of gear-train. In this reason, the TP type requires the motor having higher torque capability, and PT type requires faster motor. In terms of load on the planetary gear system, the larger torque load is applied to TP type than PT type. This distinction conditions during shifting gears lead differences in design parameters when the CGST is applied to an automobile. Therefore, the proper structure of CGST should be chosen to match the operational environment and specification of vehicle based on the results of this research.

Effect of hybrid metal-composite gear on the reduction of dynamic transmission error

Ho-Gil Yoo,정우진,김범수,박영준,강마루,Hyun Ku Lee,Moo Suk Kim,Kyoung-Sang Lee 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Gear whine noise has become one of the primary challenges facing noise, vibration, and harshness engineers; this is because the electrification of the powertrain has largely eliminated engine masking noise while increasing the working speed of the Epowertrain. In this study, a hybrid metal-composite gear was proposed to reduce gear whine noise, and its performance was evaluated by means of dynamic transmission error (DTE). The test results showed that the hybrid metal-composite gear produced an effectively lower DTE than that of alternatives, particularly when approaching resonance speeds. In addition, a reduction in resonance DTE was verified by acquiring and comparing the frequency response functions of a steel gear and a hybrid metal-composite gear. As DTE is the primary excitation source contributing to whine noise, the hybrid metal-composite gear is expected to be a significant candidate for the reduction in powertrain whine noise.

Research on a hybrid modeling method of a spiral bevel gear based on cutter simulation

이강수 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

Spiral bevel gears are essential components of mechanical devices; however, it is difficult to design, manufacture, and inspect them because their shapes are difficult to model on a computer. In this study, a method for modeling spiral bevel gears manufactured using a Gleason machine was investigated. The method to generate a gear tooth profile as point data and calculate transformation matrices between coordinate systems based on the machining process is explained in detail. The cutting volume is determined using multiple cross-sectional profiles created along the tool path, and the final gear shape is generated by subtracting the cutting volume from the workpiece. A spiral bevel gear modeling system is developed based on the proposed method, and its reliability is verified by measuring the actual gear and comparing it to the modeled shape. The verification results indicated that the modeled shape showed a 7.1 μm difference from the sample gear, implying that the proposed modeling method is reliable for modeling spiral bevel gears.

ANALYSIS OF THE SHIFTING BEHAVIOR OF A NOVEL CLUTCHLESS GEARED SMART TRANSMISSION

S. J. Kim,C. SONG,김경수,윤용산 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.1

Conventional geared transmissions use some kinds of clutches to control the power flow from an internalcombustion engine to the driveline while shifting gears. However, the shifting performance is seriously affected by the clutchengagement and an unavoidable drop in the torque may occur when the clutch is disconnected. Moreover, wear of the clutch,the need for hydraulic equipment, and the load limit may together aggravate the limits of the clutch system. For this reason,as a novel transmission without a clutch, the clutchless geared smart transmission (henceforth CGST) is proposed by ourresearch team. The CGST controls the power flow in a multiple-input gear-train by controlling the electric motor attached tothe planetary gear system. However, no CGST has been realized in an actual vehicle thus far, and the performance has beenpredicted only theoretically. In this research, we analyzed the achievable performance based on a developed CGST dynamicmodel with a typical CGST structure. In addition, a CGST gear-shifting algorithm is proposed for use with the dynamic model. From the simulation results, the CGST does not show an abrupt drop in its torque or oscillation while shifting gears due tothe absence of a discontinuous power flow. The developed dynamic model can serve as a performance reference for the CGST. Moreover, it can be used as a simulation tool for developing a gear-shifting control logic scheme.

하이브리드 선형이온원에 의한 유압 기어펌프용 Cr-DLC코팅막의 특성과 효율성능

차순용,김왕렬,박민석,권세훈,정원섭,강명창,Cha, Sun-Yong,Kim, Wang-Ryeol,Park, Min-Suk,Kwon, Se-Hun,Chung, Won-Sub,Kang, Myung-Chang 한국분말야금학회 2010 한국분말재료학회지 (KPMI) Vol.17 No.6

This paper describes the results of the application of Cr-Diamond-like carbon (DLC) films for efficiency improvement through surface modification of spur gear parts in the hydraulic gear pump. Cr-DLC films were successfully deposited on SCM 415 substrates by a hybrid coating process using linear ion source (LIS) and magnetron sputtering method. The characteristics of the films were systematically investigated using FE-SEM, nano-indentation, sliding tester and AFM instrument. The microstructure of Cr-DLC films turned into the dense and fine grains with relatively preferred orientation. The thickness formed in our Cr buffer layer and DLC coating layer were obtained the 487 nm and $1.14\;{\mu}m$. The average friction coefficient of Cr-DLC films considerably decreased to 0.15 for 0.50 of uncoated SCM415 material. The hardness and surface roughness of Cr-DLC films were measured 20 GPa and 10.76 nm, respectively. And then, efficiency tests were performed on the hydraulic gear pump to investigate the efficiency performance of the Cr-DLC coated spur gear. The experimental results show that the volumetric and mechanical efficiency of hydraulic gear pump using the Cr-DLC spur gear were improved up to 2~5% and better efficiency improvement could be attributed to its excellent microstructure, higher hardness, and lower friction coefficient. This conclusion proves the feasibility in the efficiency improvement of hydraulic gear pump for industrial applications.

하이브리드 기어의 적외선 열화상 기법을 적용한 건전성 평가

노치성 ( Roh Chi-sung ),김재열 ( Kim Jae-yeol ) 조선대학교 공학기술연구원 2016 공학기술논문지 Vol.9 No.3

The study made a hybrid gear test sample compared to the normal part and a defect part, and by using the infrared measuring technique at room temperature after cooling applied to a method of detecting a defect and a halogen lamp as a heat source through infrared measurement technology to evaluate the defect detection and quality of hybrid gear. After cooling down the spur gear, experiments were carried out using a technique to which thermography and halogen lamps are applied; according to the experiment results, the temperature data were analyzed. In case of the experiment to which thermography was applied after cooling, it was analyzed that the temperature was raised in the room temperature. As a result, the defected part had temperature lower than its surroundings while other normal parts had temperature higher than the defected part. It was possible to precisely diagnose the defected part due to gauged low temperatures at the defected part.

게임 도메인 개체명인식과 딥러닝 의도분류를 통한 주제대화 성능향상 기술

윤재민(Jae-Min Yun),지민성(Min-Seong Jee),신동춘(Dong-Chun Shin),고연정(Yeon-Jeong Ko) 한국컴퓨터정보학회 2021 한국컴퓨터정보학회 학술발표논문집 Vol.29 No.1