• Proceedings of the KSME Conference
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• 2001.06b
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• pp.635-640
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• 2001

The small gear reductioner noise is caused by gear accuracy, assembling errors, and gear backlash. This main study is an investigation on noise quality of the small gear reductioner through the change of gear backlash. In this study included Gear design parameters related the small gear reductioner, the knowledge of rattle noise related gear backlash, and the experimentation results of the small reductioner noise through change of gear backlash. At last, this study propose the least method of the small gear reductioner noise that is caused by suitable existence of gear backlash.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.67-75
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• 1997

The noise . vibration characteristics of Hypoid gears which were made from three seperate materials(SCM, TSCM, SNCM) under the identical process were investigated for the sake of durability improvement of differential gear compatible with low level noise gear set. For this study, we developed a rig experimental equipment which can perform close noise.vibration experiment of differential gear. Consequently, we could analyze the noise.vibration characteristics of final reduction gear by materials, and also we observed changes in both metallic structure and hardness according to the materials of pinion gear. In addition to this, the correlation between the vibration of the differential gear and the interior noise of the passenger vehicles was proved by analyzing the results of rig vibration experiment and field noise test.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2390-2392
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• 2001

The small gear head noise is caused by gear accuracy, assembling errors, and gear backlash. This main study is an investigation on noise quality of the small gear head through the change of gear backlash. In this study included gear design parameters related the small gear head, the knowledge of rattle noise related gear backlash, and the experimentation results of the small head noise through change of gear backlash. At last, this study propose the least method of the small gear head noise that is caused by suitable existence of gear backlash.

• International Journal of Automotive Technology
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• v.8 no.1
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• pp.75-82
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• 2007

This paper presents practical work on the reduction of gear whine noise. In order to identify the source of the gear whine noise, transfer paths are searched and analyzed by operational deflection shape analysis and experimental modal analysis. It was found that gear whine noise has an air-borne noise path instead of structure-borne noise path. The main sources of air-borne noise were the two global modes caused by the resonance of an axle system. These modes created a vibro-acoustic noise problem. Vibro-acoustic noise can be reduced by controlling the vibration of the noise source. The vibration of noise source is controlled by the modification of structure to avoid the resonance or to reduce the excitation force. In the study, the excitation force of the axle system is attenuated by changing the tooth profile of the hypoid gear. The modification of the tooth profile yields a reduction of transmission error, which is correlated to the gear whine noise. Finally, whine noise is reduced by 10 dBA.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.6
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• pp.470-475
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• 2014

In the past, transmission error(T.E.) has been identified as one of the main sources of gear whine noise, which cause serious passengers irritation at high frequency. In this study, to identify the correlation of the T.E. and gear whine noise, a T.E. measuring system was developed. By comparing the T.E. and gear whine noise level, T.E. target value which can represent the gear noise was proposed. The conclusions are followed: (I) It is possible to measure T.E. of the gear pairs (II) Similar trends are observed between T.E. and gear whine noise. (III) By observing the T.E. pattern, presence of sideband noise can be predicted. (IV) Proposed T.E. target value can be adopted to the gear manufacturing for gear noise quality management.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1475-1482
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• 2001

Nowadays reduction of gear noise in power transmission is very important, because the noise regulation is severe and demand of customer on noise is increased. To reduce gear noise, it is necessary to understand the noise characteristics of helical gear. In this work, we designed test rig for the study of gear noise and installed in semi-anechoic chamber. By using this rig, sound pressure level is measured under varying rotational speed and torque. The frequency characteristics of helical gear noise on the effect of lead errors and torque are discussed.

• 한국기계연구소 소보
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• s.15
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• pp.25-35
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• 1985

During one revolution of a gear, the intensity of the gear-meshing noise or vibration will vary, depending upon the run-out in the pitch diameter of the gear. Here noise can be produced bu excentricity of the shaft with respect to the base circle and by pitch errors. According to the noise generated is clearly dependent on the force and the amount of energy expended in elastically straining the machine member. The purpose of this paper is to discuss the analysis of the noise and technical reduction of gear noise for machine tool.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1347-1354
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• 1994

This paper deals with the experimental research, including measurement and analysis and field survey, on the causes of occurring noise defective gear boxes in hoist production plant in order to reduce the fraction of their occurrence. In this reserch following investigations are performed : measurement and gear-boxes, examination of each machining process of production, measurement and analysis of dimensional accuracy of each part, comparative vibration test with exchanging inaccurate parts. From these investigations, it is found that the machining accuracy of pinion gear tooth thickness is the most sensitive factor of noise problem. By maintaining the tooth thickness error within 0.05 mm tolerance in the gear cutting process, the fraction of noise defective gear-boxes are greatly reduced to less than 2%, where the usual rate of it has been 20-50%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.552-558
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• 2001

When operating lathe gear box which is equipped with geared transmission, it sometimes generates loud noise and excessive vibrations. In order to identify their causes, in this study, torsional and lateral vibration characteristics including critical speeds of the gear transmission system are firstly analyzed using lumped parameter models. Natural frequencies and mode shapes of the gear box structure are also analyzed by using the modal test. Furthermore, measured vibration and noise signals during operations are analyzed and compared with theoretical analysis results. After all, it is concluded that the primary cause of the excessive noise and vibrations is the resonance between gear meshing frequency including its side bands, the frequencies of shaft bending and torsional vibrations, and the natural frequencies of the gear box structure. Consequently the noise and vibration levels are greatly reduced by avoiding resonance between the natural frequencies and gear meshing frequencies through the rearrangement of the gears on the transmission shaft without any gear ratio change.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.7
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• pp.669-674
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• 2013

To design the optimized low noise planetary gear sets, a program called pRMC(planetary run many cases) is developed. The pRMC is especially using a combination analysis method for all gear specifications and also able to analyze any type of planetary gear sets. The pRMC is composed of the 5 sections those are generate, setting, evaluate, combine and analysis. After calculating all candidate gear sets, the pRMC could show many results that represent the character of each gear set including the transmission error which is the main gear noise factor, the contact ratios, the bending stress and so on. By comparing the results objectively, user could predict and select the optimized gear set which has quiet noise level and desired durability. The planetary gear designed by pRMC could have reduced noise and vibration level from 5 to 10 dB than previous-designed one.