• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.741-744
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• 2004

In concrete pavements with uniform tining space, the whine noise which has high frequency spectrum related to the uniform tining space exist. In this paper, randomization procedure of tining space for concrete pavements is proposed. The proposed procedure developed based on the LCG(Linear Congruential Generator) algorithm. And the factor concerned in the procedure are drag span length, number of different tining space, ratio of each tining space, total tinings of each size, sequence of actual tining.

• 한국소음진동공학회논문집
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• 제19권2호
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• pp.127-137
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• 2009

Hypoid gears are widely used in rear drive and 4WD vehicle axles. Investigation of their sensitivity to deflections is one of the most important aspects of their design and optimization procedures. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface. Transmission error is tested on an axle assembly triaxial real car load condition.

• 한국기계가공학회지
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• 제11권5호
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• pp.42-47
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• 2012

Construction equipment is heavily loaded during normal operation. In recent years, there is a trend that lower gear noise levels are demanded for drivers to avoid annoyance and fatigue during operation. For articulated hauler's final drive, meshing transmission error(T.E.) is the excitation that leads the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. This paper presents a method for the analysis of the tooth profile modification, and the prediction of transmission error under the loaded torques for the spur gear pair of the articulated hauler's final drive. And the transmission error, transmission error harmonics and contact stress are also calculated and compared before and after tooth modification under one torque. The simulation result shows that the transmission error and contact stress under the loads can be minimized by the appropriate tooth profile modification.

• 소음진동
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• 제10권1호
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• pp.107-116
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• 2000

The gear whine noise caused by tooth profile, elastic deformation, machining error, wear is directly correlated with the transmission error of mating gear. It is very important to build up the synthesized countermeasure by the modeling of the excitation forces and analyzing the vibratory characteristics. The mathematical models on the elements of vehicle transmission which is composed of helical gears, bearings, shafts and cases are developed. The elements are assembled by the substructure synthesis method. The cases of transmission are modeled by ANSYS. The system model of vehicle transmission is also verified by the experiments.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1040-1047
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• 2008

Hypoid gears are widely used in rear drive and 4WD vehicle axles. Investigation of their sensitivity to deflections is one of the most important aspects of their design and optimization procedures. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface. Transmission error is tested on an axle assembly triaxial real car load condition.

• 한국기계가공학회지
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• 제10권4호
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• pp.70-75
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• 2011

Nowadays, modern gearboxes are characterized by high torque load demands, low running noise and compact design. Also durability of gearbox is specially a major issue for the industry. For the gearbox which used in wind turbine, gear transmission error(T.E.) is the excitation that leads the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. In this paper, tooth modification for the high speed stage is used to compensate for the deformation of the teeth due to load and to ensure a proper meshing to achieve an optimized tooth contact pattern. The gearbox is firstly modeled in Romax software, and then the various combination analysis of the tooth modification is presented by using Windows LDP software, and the prediction of transmission error under the loaded torque for the helical gear pair is investigated, the transmission error, contact stress, root stress and load distribution are also calculated and compared before and after tooth modification under one torque condition. The simulation result shows that the transmission error and stress under the loads can be minimized by the appropriate tooth modification.

• 소음진동
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• 제8권5호
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• pp.841-848
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• 1998

In the gear manufacturing, tooth modification is usually applied for the prevention of tooth impact during the loading. In contrary, tooth profile error causes amplifying the whine noise which is cumbersome to reduce in the automobile gear box. So optimum quantity of the modifications must be obtained for the good performance in the vibrational sense. In this paper, a formulation to define the tooth curve by considering the profile manufacturing error and loading deformation of the gear tooth is suggested and the transmission error and loading deformation of the gear tooth is suggested and the transmission error with modified tooth in the gear system is evaluated. A pair of gear set is mathematically modelled. The equivalent excitation in the gear vibratonal model is formulated. For the experimental evaluaton on the derived transmission error function, a simple geared system is set up in which the gears are designed to give pre-designed tooth profile modification and manufactured by CNC Wire Cutting Machine. Under slow speed operaton, the transmission error of the gear pair is measured by using two rotational laser vibrometers, compared with the calculated one of which the result shows good agreement.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.225-232
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• 2007

A tooth profile modification for loaded gears is used to avoid a tooth impact. Since a tooth profile error causes amplification of the cumbersome whine noise in automotive gear transmissions, an optimal quantity of tooth profile modifications must be obtained for good performance in the vibration sense. In this paper, a tooth profile modification curve considering profile manufacturing errors and elastic deformation of the gear tooth is formulated; in addition, transmission errors of the gear system with modified teeth are verified. The equivalent excitation due to transmission errors is formulated. For experimental evaluation of the transmission error, the transmission error for a simple gear system was measured by two rotational laser vibrometers. Finally, we perform a comparative analysis between the calculated and measured responses to the excitations due to the transmission error to verify the practicability of the application to automotive transmissions.

• 한국기계가공학회지
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• 제14권2호
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• pp.14-18
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• 2015

In recent years, world is faced with a transportation energy dilemma, and the transportation is almost dependent on a single fuel - petroleum. However, Hybrid Electric Vehicle (HEV) technology holds more advantages to reduce the demand for petroleum in the transportation by efficiency improvements of petroleum consumption. Therefore, there is a trend that lower gear noise levels are demanded in HEV for drivers to avoid annoyance and fatigue during operation. And meshing transmission error (T.E.) is the excitation that leads to the tonal noise known as gear whine, and radiated gear whine is also the dominant source of noise in the whole gearbox. In this paper, the analysis of gear tooth profile and lead modification is firstly presented, and then, the different transmission error of no mesh misalignment and mesh misalignment under one loaded torque for the 1st gear pair of HEV gearbox was investigated and compared. At last, the appropriate tooth modification was used to minimize and compare the transmission error of the gear pair with mesh misalignment under the loaded torque.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.851-856
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• 2012

Automotive turbochargers have become common in gasoline engines as well as diesel engines. They are excellent devices to effectively increase fuel efficiency and power of the engines, but they unfortunately cause several noise problems. The noises are classified into mechanical noises induced from movement of a rotating shaft and aerodynamic noises by air flow in turbochargers. The mechanical noises are whine and howling noises, and the aerodynamic noises are BPF (blade-passing frequency), pulsation, surge, some special frequency noises. These noises are bothering passengers because their levels are higher or their frequencies are clearly separated from engine or vehicle noises. The noise investigated in this paper is a BPF noise induced by compressor wheels, whose frequency is the multiplication of the number of compressor wheel blades and its rotational speed. The noise is strongly dependent upon the geometry of wheels and the number of blades. This study tried to apply a groove close to the inlet side of compressor wheels in order to reduce the BPF noise. The groove has successfully reduced the noise of narrow band frequency of a turbocharger. It shows that the groove could reduce the wide band frequency noise, the compressor BPF noise with a best shape of the groove.