• 한국정밀공학회지
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• 제28권3호
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• pp.370-376
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• 2011

Recently, the application range of plastic gears is widely expanding by the development of engineering plastics with good mechanical properties. Plastic gears have excellent performances such as light weight, water resistance and vibration absorbing ability for metallic gears. In this study, the optimization of injection molding process was done for the large disk type plastic gears of auto phoropter. Design Of Experiment (Taguchi method) was adopted to find a tendency of molding conditions that influence the flatness of disk type gear. Four main factors for molding conditions were selected based on injection temperature, filling time, packing pressure and mold temperature. Also, Filling, packing and cooling analyses were carried out to evaluate Z directional deflection of large disk type gear by using the simulation software (Moldflow) based on the DOE. From the results, it was found that the injection temperature and packing pressure are the most sensitive parameters for the Z directional deflection of large disk type gears.

• 한국정밀공학회지
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• 제17권9호
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• pp.202-209
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• 2000

In recent years the concern of designing multi-stage gear drives increases with the more application of gear drives in high-speed and high-load. until now however research on the gear drive design has been focused on single gear pairs and the design has been depended on experiences and know-how of designers and carried out commonly by trial and error. We propose the automation of the dimensional design of gears and the configuration design for gear arrangement of two-and three-stage cylindrical gear drives. The dimensional design is divided into two types of design processes to determine the dimensions of gears. The first design process(Process I) uses the total volume of gears to determine gear ratio and uses K factor unit load and aspect ratio to determine gear dimensions. The second one(Process II) makes use of Niemann's formula and center distance to calculate gear ratio and dimensions. Process I and II employ material data from AGMA and ISO standards respectively. The configuration design determines the positions of gears to minimize the volume of gearbox by simulated annealing algorithm. Finally the availability of the design algorithm is validated by the design examples of two-and three-stage gear drives.

• International Journal of Precision Engineering and Manufacturing
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• 제2권4호
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• pp.5-11
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• 2001

Vibration and noise of gears is doc to the transmission error and the vibration exciting force caused by the periodically alternating tooth stiffness. Transmission error is the rotation delay between driving and driven gear caused by manufacturing error, alignment error in assembly and so on. Tooth stiffness changes with the proceeding mesh of teeth. The purpose of this study is to develop how to calculate simultaneously the optimum amounts of tooth profile modification. end relief and crowning by minimizing the vibration exciting force of helical gears. We estimate the vibration exciting force by the meshing analysis of gears. Formulated constraints of this problem consist of contact ratio and strengths of gear teeth such as tooth bending strength, surface durability, and scoring. ADS(Automated Design Synthesis) is used as an optimization tool. We also investigate the relation between the aspect ratio and the optimum values of tooth modification. The proposed method can calculate the optimum amount of tooth modification automatically and is expected to be practically useful to resolve the problem of vibration of helical gears.

• 한국기계가공학회지
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• 제15권4호
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• pp.67-72
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• 2016

Planetary gear sets are widely used in power transmission components, which have high efficiency and good durability. Their most important design parameter is the load-sharing characteristics among several planetary gears. In this study, the load sharing of planetary gears was analyzed according to the carrier pinhole position error of planetary gear sets. The loads acting on planetary gears varied with the pinhole position error of the carrier, and the load sharing of planetary gears improved as the input load increased. In addition, the load of the planetary gear with a carrier pinhole position error was relatively higher than that of other planetary gears without carrier pinhole position errors. This trend appeared more clearly in the non-floating-type carrier than the floating-type carrier.

• 한국전자통신학회논문지
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• 제13권5호
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• pp.1023-1028
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• 2018

직접 접촉 방식의 기계적인 결합을 사용하는 기어는 접촉 마찰로 인한 소음, 진동, 발열 등의 문제가 지속적으로 제기되어왔기 때문에, 비접촉 자기(magnetic)결합을 이용한 마그네틱 기어(magnetic gear)가 제안되었다. 마그네틱 기어에 대한 연구 중 동일한 기어비에서 극수에 따라 손실의 차이가 발생함을 확인하였으며, 철손과 영구자석 와류손이 극수에 따라 일정한 경향성을 보일 것으로 예상되어 연구를 진행하였다. 본 논문에서는 마그네틱 기어의 극수에 따른 경향성을 확인하고 구체화하여 마그네틱 기어의 효율 개선 설계의 기반을 마련하였다.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.355-362
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• 2021

동축 마그네틱 기어는 비접촉 동력전달을 사용하기 때문에 기존 기계식 기어의 동력전달과정에서 발생하는 마찰, 마모, 소음, 발열을 최소화할 수 있다. 현재 다양한 산업에 적용하기 위한 연구가 활발히 진행되고 있으나 동축 마그네틱 기어가 갖는 특징 중, 높은 기어비에서 토크밀도가 급격히 감소하는 문제가 거론되었다. 본 논문은 높은 토크밀도를 갖는 저 기어비 동축 마그네틱 기어를 이용하여, 이들을 다중으로 결합하는 방향을 제시하였다. 해당 방법의 유효성을 확인하기 위해 단일형태의 고 기어비 모델과 토크밀도를 비교하고 다중 동축 마그네틱 기어의 기어비 조합을 분석함으로써 가장 우수한 조합을 선정하는 설계 방향을 나타내었다.

• 한국기계가공학회지
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• 제20권8호
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• pp.1-10
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• 2021

Gears, which rotate and transmit power by interlocking two cogwheels, were invented in BC. They have been used in various systems, including industrial machinery, transportation devices, and living facilities, through the industrial revolution. Regardless of how they are used, gears are a major source of noise and vibration. Many effective measures are being taken to reduce the radiation noise generated from gears, most commonly by lubrication. Lubrication in gear units reduces friction on interlocking gear surfaces, dampening radioactive noise. This can be very useful for quiet gear design if these lubricating damping effects can be reflected in the analytical phase for gear design. This study experimentally confirms the properties of lubricated and non-lubricated radioactive noise by designing a decelerator gearbox and analyzing the radioactive noise characteristics by torque, rotation, and the number of gears using computer analysis.

• 한국정밀공학회지
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• 제12권8호
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• pp.63-72
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• 1995

Closed-die forging of spur gears with hollow cylindrical billet has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduced to represent the forging die profile. In the analysis, the deformation region has been divided into nine zones. A constant frictional stress has been assumed on the contacting surfaces. Utilizing the formulated velocity field, numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth and friction factor, on the forging of spur gears. Hardness and accuracy of forged gears are measured. The following results have been obtained: (1) It is verified that an axisymmetric deformation zone exists between root circle and center of gear through forged gears. (2) The average relative forging pressure is predominantly dependent on the number of teeth and increases near the final filling stage as the addendum modification coefficient increases. (3) Close agreement was found between the predicted values of forging load and those obtained from experimental results.

• 한국산업융합학회 논문집
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• 제9권4호
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• pp.269-276
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• 2006

Strength Design method for involute spur gears is developed. The developed gear strength design system can design the optimized gear that minimize the number of pinion teeth with face tooth. Method of optimization is matrix form which is developed from this study. Design variables are transmitted power, gear volume, gear ratio, allowable contact stress and allowable bending stress, etc. Gear design method developed this study can be apply to the gears of plants, machine tools, automobiles.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.837-841
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• 1996

It is the eccentricity that determines most of the characteristics of the elliptic gears. Accoding to the theoretical tooth profiles, two pairs of the elliptic gears were manufactured by using CNC wire cutting machine. For harmonious rotating motion, it is necessaryto consider operating pressure angle and module not to generate undercut. The characteristics of vibration were investigated by analyzer.