Efficiency Analysis of Planetary Gear Train under Ring Gear Deformation

Shao Yimin,Li Xuzhong,Li Hongwu,Chen Yan,Xu Jin 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10

Transmission efficiency is a key parameter of planetary gear train, it has a significant effect on power density of transmission systems. Usually, ring gear is regard as a rigid part in the efficiency calculation of planetary gear train. However, most of the planetary gear train adopt flexible ring gear design, which means the deformation of ring gear is large. In addition, the deformation of the ring gear leads to the change of the meshing relationship of the gears in the planetary gear train, thus both the dynamic load, sliding speed and friction force in the planetary gear train are affected. Besides, the meshing power loss in planetary gear train is also changed. Therefore, this paper takes the elastic deformation of the flexible ring gear and the dynamic friction force along the contact path of the gear teeth into consideration. Then the vibration responses of the planetary gear train are calculated based on a new established concentrated mass dynamic model. Next, power loss on the meshing interface and the meshing efficiency of the planetary gear trains are evaluated with the consideration of ring gear deformation. The calculation results show that the elastic deformation of the ring gear has a great influence on the meshing efficiency of the planetary gear train.

1.7톤급 소형 굴착기용 주행 감속기의 복합 유성기어류에대한 강도 평가

남석주,배명호,조연상 한국트라이볼로지학회 2022 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.38 No.1

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

풍력발전용 피치 드라이브 시스템의 복합 유성기어류에 대한 피로 강도해석

김광민(KwangMin Kim),배명호(MyungHo Bae),조연상(YonSang Cho) 한국트라이볼로지학회 2021 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.37 No.2

Wind energy is considered as the most competitive energy source in terms of power generation cost and efficiency. The power train of the pitch drive for a wind turbine uses a 3-stage complex planetary gear system in being developed locally. A gear train of the pitch drive consists of an electric or hydraulic motor and a planetary decelerator, which optimizes the pitch angle of the blade for wind generators in response to the change in wind speed. However, it is prone to many problems, such as excessive repair costs in case of failure. Complex planetary gears are very important parts of a pitch drive system because of strength problem. When gears are designed for the power train of a pitch drive, it is necessary to analyze the fatigue strength of gears. While calculating the specifications of the complex planetary gears along with the bending and compressive stresses of the gears, it is necessary to analyze the fatigue strength of gears to obtain an optimal design of the complex planetary gears in terms of cost and reliability. In this study, the specifications of planetary gears are calculated using a self-developed gear design program. The actual gear bending and compressive stresses of the planetary gear system were analyzed using the Lewes and Hertz equation. Additionally, the calculated specifications of the complex planetary gears were verified by evaluating the results from the Stress - No. of cycles curves of gears.

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.

Design of a non-circular planetary-gear-train system to generate an optimal trajectory in a rice transplanter

Bae, Kang-Yul,Yang, Young-Soo Taylor Francis 2007 Journal of engineering design Vol.18 No.4

<P> The transplanting accuracy of a rice transplanter for picking, conveying and transplanting seedlings mainly depends on the trajectory as well as the return motion of the hoe. The trajectory of the hoe has to be optimized in treating seedlings for a prevailing soil condition. For better transplanting accuracy, a planetary-gear-train system, instead of the four-bar linkage system is used to design a transplanting mechanism. This study proposes a theoretical design method for a transplanting mechanism; the method designs non-circular gears of a planetary-gear-train system for the hoe to trace a prescribed trajectory. An optimization method was used to determine the arm length and tool length; inverse kinematics to determine the configuration angles of the two links and the roll contact condition in transmitting motion between the gears; and a linearization approach to obtain the shapes of the gears. Based on the proposed method, the shapes of the gears and the lengths of the tools of the planetary-gear-train system are determined for three prescribed trajectories. A commercialized package program (ADAMS) is used to carry out a kinematic simulation to confirm that the gear-train system configured from the proposed method is adequate for the transplanting mechanism.</P>

비원형 유성기어열을 사용한 이앙기 식부기구의 설계

배강열(Kang Yul Bae) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.12

Transplanting accuracy of a rice transplanter mainly depends on the trajectory of the hoe for picking, conveying and transplanting of seedlings as well as the return motion. The trajectory can be decided and prescribed to be suitable in treating seedlings for a prevailing soil condition. For the purpose of the transplanting accuracy, the design of a transplanting mechanism would be carried out using a planetary-gear-train system instead of the four bar linkage system. In this study, a design method of transplanting mechanism is theoretically proposed by synthesizing a noncircular planetary-gear-train system for the tool (hoe) to trace a prescribed trajectory. The method utilizes an optimization approach to decide the lengths of an arm and a tool, the inverse kinematics to figure out the configuration angles of the two links, the roll contact condition in transmitting motion between the gears, and a linearization approach to obtain the shapes of the gears. Based on the proposed method, the shapes of the gears and the lengths of the tools of the planetary-gear-train system are determined for three prescribed trajectories. A kinematical simulation with a commercialized package program is also carried out to confirm that the gear-train system synthesized with the proposed method is able to trace the prescribed trajectory.

DYNAMIC MODELING OF THE ELECTRO-MECHANICAL CONFIGURATION OF THE TOYOTA HYBRID SYSTEM SERIES/PARALLEL POWER TRAIN

C. MANSOUR,D. CLODIC 한국자동차공학회 2012 International journal of automotive technology Vol.13 No.1

The hybridization of the conventional thermal vehicles nowadays constitutes a paramount importance for car manufacturers, facing the challenge of minimizing the consumption of the road transport. Although hybrid power train technologies did not converge towards a single solution, series/parallel power trains with power-split electromechanical transmissions prove to be the most promising hybrid technology. In fact, these power trains show maximum power train overall efficiency and maximum fuel reduction in almost all driving conditions compared to the conventional and other hybrid power trains. This paper addresses the model and design of the electro-mechanical configuration of one of the most effective HEV power trains: case study of the 2nd generation Prius. It presents the simulation work of the overall operation of the Toyota Hybrid System (THS-II) of the Prius, and explores not only its power-split eCVT innovative transmission system but also its overall supervision controller for energy management. The kinematic and dynamic behaviors of the THS-II power train are explained based on the power-split aspect of its transmission through a planetary gear train. Then, the possible regular driving functionalities that result from its eCVT operation and the energy flow within its power train are outlined. A feedforward dynamic model of the studied power train is next proposed, supervised by a rule-based engineering intuition controller. The energy consumption of the THS-II proposed model has been validated by comparing simulation results to published results on European, American and Japanese regulatory driving cycles.

소음/진동을 고려한 발전설비용 감속기 개발

이형우(Hyoung Woo Lee),박철우(Chul Woo Park) Korean Society for Precision Engineering 2008 한국정밀공학회지 Vol.25 No.11

A dynamic model of reducer for generating facility of electric power having bevel gear pair and planetary gear train is developed by lumped method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of bevel gear pair and planetary gear train are considered. Exciting forces of high reducer for generating facility of electric power are considered as the mass unbalance of the rotors, misalignment and a function of gear transmission error. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not critical speed.

Study on Dynamic Characteristics and Load Sharing of a Herringbone Planetary Gear with Manufacturing Errors

Fei Ren,Datong Qin,Teik Chin Lim,류성기 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

In this paper, a new and generalized dynamic model for a herringbone planetary gear train (HPGT) is proposed to investigate thefree and forced vibration characteristics, as well as load sharing characteristics by employing the lumped-parameter approach. Theproposed model takes into account manufacturing eccentric errors of the components and tooth profile errors of all gears. The modelcan be used for the vibration performance and dynamic load sharing analysis of the HPGT with different types of manufacturingerrors and arbitrary number of planets. The free and forced vibration, as well as the load sharing of an HPGT with three planetsare numerically computed with the model presented, and these are analyzed respectively in time domain and frequency domain. Theeffects of the manufacturing eccentric error and tooth profile error as well as component float on load sharing are discussedrespectively. Results indicate that manufacturing errors have an impact on dynamic characteristics and load sharing. The float cansignificantly reduce the load sharing coefficient of the system.

입력분기방식 하이브리드 전기자동차의 구동계 구조에 따른 동력 성능 비교 분석

김정민(Jeong-Min Kim) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.4

In this study, the performances of five input split type hybrid electric vehicle sub-drivetrains were analyzed. The five sub-drivetrains consist of chain, helical gears and planetary gears. For the analyzing above five sub-drivetrains, the mathematical equations were derived. From the analysis, we found that the sub-drivetrain with chain shows slower acceleration performance and larger energy consumption on the city driving. And, the sub-drivetrain with only helical gear shows smallest energy consumption on the city driving. If the sub-drivetrain can change its gear speed, it shows fastest acceleration performance, but it has largest energy consumption on the city driving due to its additional auxiliary components.