Development and research on electric vehicles in power transmission system are increasing as the demand for ecofriendly and autonomous vehicles increases across the industry. In order to reduce noise, research on high efficiency and low noise due to electrification of the gearbox system is being actively conducted, such as applying design technology to optimize the shape of the gear and increase rigidity. In particular, research on low noise is active because the noise of the electric gearbox could be easily recognized in a vehicle, even with small noise due to its frequency characteristics. Therefore, in this study, effects of main specifications of gears on noise and power loss were studied and analyzed through a Parametric Study. Characteristics of the proportional relationship between noise and power loss according to major specifications were analyzed. Based on study results, NVH analysis in the gear system was performed. After that, actual data were secured through test measurements and a noise reduction effect of 4.4 dB was confirmed.
The gear overlap ratio shows the characteristics of the spur gear and the helical gear and varies according to the torsional angle. The gear ratio, tooth width, and center distance, which are restricted in a space of performance and manufacturing and design in the gearbox, are fixed. A parametric study on modules, the number of teeth, and torsion angles was conducted to analyze the relationship between the overlap ratio and PPTE. Then, contact analysis was performed by correcting the tooth profile to improve the transmission error. Contact analysis was performed through correction of the tooth modification to improve transmission error, and the noise was analyzed according to the overlap ratio by applying a noise prediction equation.
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Study on the Modification of the Contact Pattern and Teeth Shape of Tapping Device Drive Gears Sung-Min Moon, Yong-Woo Park, Do-Young Lee, Sung-Ki Lyu Journal of the Korean Society of Manufacturing Process Engineers.2025; 24(9): 76. CrossRef
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Noise, Vibration and Harshness (NVH) is a comprehensive issue of manufacturing quality that gives the purchaser a superficial feeling. The NVH performance of the vehicle has undoubtedly become an important factor and basis for consumers. When the internal combustion engine is working, it generates a strong noise thus making it necessary to reduce the vibration and noise. The noise of diesel engine is divided into acoustic and structural radiation noise according to different radiation paths. The structure radiated noise is mainly caused by the combustion noise and mechanical transmission noise, while mechanical transmission noise is mainly generated by the meshing gears in the diesel. This paper aims to solve the problem of a diesel engine abnormal gear whine noise under idling conditions with a combination of simulation and experiment. By gear micro-modification, the gear train whine noise is reduced by minimizing the PPTE of the gear train. The comparison of the simulation to benching testing shows a good correlation. It provides an optional solution to the modification proposal of the engine gear train, which uses the similar structure for the engine. Future work will dwell on a better understanding of the gear rattle noise, which will be discussed later.
Transportation machine manufacturers are putting in efforts on research based on weight reduction. One of the representative materials for weight reduction is Fiber Reinforced Plastic (FRP). Increased used of FRP, glass fiber and carbon fiber could be a way of weight reduction. It is almost unavoidable to generate holes or notches during structural design. Little research have been carried out based on cracks with respect to materials used for design. The utilization of finite element analysis and the reliability of the analysis methods are increasing in order to promptly cope with the damages in materials. In this study, Compact Tension (CT) model based on ASTM E647 was designed using SM45C, steel for structural use, short fiber Glass Fiber Reinforced Plastic (GFRP), and woven type Carbon Fiber Reinforced Plastic (CFRP). In addition, J-Integral, which is a factor for determination of growth of crack that appears in cracks, was applied to general structure analysis. J-Integral is an equation of the body force of the material and strain energy in accordance with the loading force, and illustrates the crack growth using energy release rate. J-Integral values of SM45C, short fiber GFRP and woven type CFRP were found to be approximately 74,978 mJ/mm², 7492.3 mJ/mm² and 6222.4 mJ/mm², respectively.
This study focuses on these issues and includes the static fracture experiments with two forms of specimens; aluminum foam DCB and TDCB bonded with the type of mode III, a simulation static analysis to verify this experiment, and analysis of fracture behavior of adhesive interface of structures attached with aluminum foam by shape and thickness. The thickness of DCB and TDCB specimens designed in this study are set as variable t, and each thickness is t = 35 mm, 45 mm, 55 mm. According to forced displacements, the maximum reaction forces of DCB specimens due to thickness were approximately 0.35 kN, 0.45 kN, 0.54 kN, and the maximum reaction force of TDCB were approximately 0.4 kN, 0.52 kN, and 0.63 kN respectively. We expect the data according to variables to be easily investigated without a separate testing process, and effective analysis of the mechanical characteristics of aluminum foam DCB and TDCB.
Nowadays, noise, vibration, and harshness (NVH) is a comprehensive issue related to manufacturing quality, it gives the purchaser the most direct and superficial feeling. Following economic development, the improvement of people’s living standards, and the expansion of the export market, it has become urgent to develop and produce some better NVH performance motorcycles. In this paper, the transmission of a scooter gearbox is modeled and analyzed by software. Then, the first helical gear pair of the gearbox was investigated through static analysis. Lastly, optimized modification was verified using B&K testing equipment in the semi-anechoic room. The comparison of the simulation to prototype during testing showed a good correlation, which means simulation optimization can greatly improve the research and development efficiency of the transmission system.
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The aim of this study is to design the gearbox of an electric vehicle using the rear-wheel drive. The gearbox is a set of revolving gears and shafts based on programmed torque and rotations per minute (rpm). In this case, safety, strength and durability of gears and shafts was considered. In the narrow vehicle, a light case is used. In addition to gear safety and deflection, the weight of the vehicle was reduced. The electric vehicle reducer gearbox was modeled according to the vehicle room. The strength analysis was conducted using finite element method (FEM). After analyzing the strength using FEM to verify stress distribution, the design was modified, and compared with the results of altered design using FEM. As a result, the reducer gearbox of electric vehicle was designed according to incorporate gear safety, deflection of each gear, durability, and analysis of finite elements followed by test assessment, vehicle installation and the production of real parts.
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Gears have been used as primary machine elements that comprise a power transmission system in many mechanical engineering fields. This paper presents research on the optimization of gear geometries. Drive unit consists of many spur gears in inner structure, and efficient alignment will be needed for fine performance of the unit. If mesh misalignments occur, load distribution would be unbalance and concentrated in one side. It is directly connected many problems such as banding deformation to shaft, gear and housing. As much as deformation occur these machine element’s duty cycle will be decreased. Moreover due to unbalanced load distribution, noise and transmission error cause serious defect on gear performance. In order to solve this matter, it is necessary to modify tooth profile for balanced load distribution. There are two different solutions. One is micro-geometry optimization and the other is macro-geometry optimization. In this paper we choose the first one because it just takes minimum gear modification but more effective. To implement this, the latest simulation technology will be used and it allows not only the defection of gear mesh misalignments but also how to modify gear profile and lead slope. Before make prototype gear production, it provides more helpful information.
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A Review of Recent Advances in Design Optimization of Gearbox Zhen Qin, Yu-Ting Wu, Sung-Ki Lyu International Journal of Precision Engineering and Manufacturing.2018; 19(11): 1753. CrossRef
An essential mechanical element in an industrial machine is a reducer, which transfers the rotation of an electrical motor or engine to another part with amplified torque. Some reducers, such as planetary reduction gears, a harmonic reducer, or a cycloid reducer, have been applied in various industries. Given the increase of demand for reducers with high precision, compact size, and high load capacity for use in industrial robots, the cycloid reducer has stood out. The cycloid reducer, compared with planetary reduction gears, has some merits, which include a larger reduction gear ratio at only one stage, higher durability, improved efficiency, and a larger torque because of its high tooth-contact ratio despite its being small. This paper presents a design technique for a cycloid reducer intended, because of those merits, for use in remote weapons systems of armed vehicles. In order to verify the performance of the cycloid reducer, we carried out experiments and analyzed the results systematically.
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A popular approach to optimize the performance of a gear transmission system is the modification of the gear tooth microgeometry, which includes the intentional removal of material from the gear teeth flanks, so that the shape is no longer a perfect involute. Such modifications compensate teeth deflections under load, and the resulting transmission error is minimized under a specific torque. Therefore, micro-geometry modifications can be applied on the involute (or profile) and lead of the gear teeth. In order to study the tooth micro-geometry optimization, this research selected a mass produced planetary gear type drive reducer as a prototype. The original design was modeled by a commercial software named Romax Designer, which analyzes and optimizes different types of gear power transmission systems. The series analysis results obtained reveal some anomalies that require modification. Based on the result, optimization and gear tooth modification were done to deal with the load distributions on gear tooth, gear durability problem, safety factor and bearing life problem. This thesis presents the outstanding performance improvement obtained after such optimization.
Citations
Citations to this article as recorded by
Development of a Prediction Model for the Gear Whine Noise of Transmission Using Machine Learning Sun-Hyoung Lee, Kwang-Phil Park International Journal of Precision Engineering and Manufacturing.2023; 24(10): 1793. CrossRef
Influence of Open Differential Design on the Mass Reduction Function Mirko Karakašić, Pejo Konjatić, Hrvoje Glavaš, Ivan Grgić Applied Sciences.2023; 13(24): 13300. CrossRef
Large Curvic Coupling Gear for Ultraprecision Angle Division Using FEM Yoon-Soo Jung, Jia-Chen Gao, Gyung-Il Lee, Ku-Rak Jung, Jae-Yeol Kim International Journal of Precision Engineering and Manufacturing.2021; 22(3): 495. CrossRef
A Review of Recent Advances in Design Optimization of Gearbox Zhen Qin, Yu-Ting Wu, Sung-Ki Lyu International Journal of Precision Engineering and Manufacturing.2018; 19(11): 1753. CrossRef
Simulation and Experimental Analysis for Noise Reduction of a Scooter Gearbox Qi Zhang, Jing Zhang, Zhong Hua Liu, Jian Hua Lv, Zhen Qin, Sung Ki Lyu Journal of the Korean Society for Precision Engineering.2018; 35(8): 777. CrossRef
A decoupling method for multi-stage gear transmission error Dong Guo, Honglin Li, Yawen Wang, ShuaiShuai Ge, Xuebin Bai Journal of the Brazilian Society of Mechanical Sciences and Engineering.2023;[Epub] CrossRef
Nowadays, lower gear vibration and noise are necessary for drivers in automotive gearbox, which means that transmission gearbox should be optimized to avoid noise annoyance and fatigue before quantity production. Transmission error (T.E.) is the excitation factor that affects the noise level known as gear whine, and is also the dominant source of noise in the gear transmission system. In this paper, the research background, the definition of T.E. and gear micro-modification were firstly presented, and then different transmission errors of loaded torques for the spur gear pair were studied and compared by a commercial software. It was determined that the optimum gear micro-modification could be applied to optimize the transmission error of the loaded gear pair. In the future, a transmission test rig which is introduced in this paper is about to be used to study the T.E. after gear micro-geometry modification. And finally, the optimized modification can be verified by B&K testing equipment in the semi-anechoic room later.