• 융복합기술연구소 논문집
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• 제10권1호
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• pp.25-29
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• 2020

Magnetic gears of non-contact power type have great advantages in terms of maintenance and repair than mechanical gears, and are used in various ways. Harmonic gears can derive a higher gear ratio than conventional gears through power transmission through a unique rotation mechanism. Magnetic harmonic gears, in which the gear teeth of the harmonic gears are replaced with magnets, have the advantages of both gears, but are difficult to implement and practical, so many studies are being conducted. In this study, we check whether the results of various types of magnetic gears can be applied to harmonic gears. By applying the axial type magnetic gear to the harmonic gear, the characteristic analysis is conducted to see if the result comparable to the existing radial type magnetic harmonic gear is obtained.

• 융복합기술연구소 논문집
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• 제12권1호
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• pp.7-12
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• 2022

The reduction ratio of the magnetic gear is determined by the ratio of the number of poles between the high-speed permanent magnet layer and the low-speed permanent magnet layer. In general, it is known that the greater the least common multiple of both poles, the smaller the torque ripple called by cogging of the magnetic force generated in the magnetic gear. However, little is known about the effect of the harmonic modulator that filters the magnetic field in the magnetic gear to magnetically couple the high-speed side and the low-speed side except for the number of poles. In this study, torque ripple characteristics according to changes in modulator shape such as opening ratio and tooth thickness are analyzed using a finite element analysis tool.

• Tribology and Lubricants
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• 제4권2호
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• pp.60-67
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• 1988

Conventional theory of gear mechanism can't be applied to analyze the harmonic drive due to specific movement of the teeth. This paper deals with an analysis of kinematics and geometry of the tooth engagement of a harmonic drive comprising circular spline, flexspline and wave generator. A theoretical new tooth profile of the flexspline in meshing internal rigid gear with involute profile is obtained. Characteristics of harmonic drive reducer are shown according to parameters such as deviation coefficient, deviation distance, addendum modification coefficient. As an example, the design of harmonic drive with 1:80 reduction ratio is presented.

• 한국소음진동공학회논문집
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• 제12권12호
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• pp.921-928
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• 2002

Main sources of the nitration of a gear-pair system are backlash and transmission error, the difference between required and actual rotation during gear meshing. This paper presents the nonlinear dynamic characteristics of gear motions due to the existence of backlash and periodic variation of meshing stiffness, which is assumed as a one-term harmonic component. Gear motions are classified as three types with the consideration of backlash. Each response is calculated using the harmonic balance method and confirmed by numerical integration. The responses with the increase of the rotating speed show abrupt changes in its magnitude for the variation of the preload, exciting force, and damping coefficient. The result also shows that there is a chaotic motion with some specific design parameters and operating conditions In gear diving system. Consequently the design of gear driving system with low nitration and noise requires the study on the effects of nonlinear dynamic characteristics due to stiffness variation and backlash.

• 한국생산제조학회지
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• 제24권3호
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• pp.348-354
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• 2015

Using a magnetic gear, the speed and torque of the driving axis can be decreased and increased, respectively, similar to a mechanical speed reducer. In particular, because the driving side can be isolated mechanically from the load side, the magnetic gear was developed for application with environmental constraints. Of the existing topologies used for the magnet gear, the filtering method of a specified magnetic component is the most competitive. In this paper, a novel unified harmonic modulator is applied to filter the specified component. The torque conversion method using this modulator is described in detail, and the key factors of the modulator are derived from the influence on the resulting torque. The experimental setup was constructed and its torque transmission efficiency measured for varying loads. The transient characteristic from an excessive load is compared with the theoretical simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.403-404
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• 2013

• 한국정밀공학회지
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• 제22권11호
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• pp.111-117
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• 2005

The vibration problems associated with gear coupled rotors have been the focus of much engineering work. These systems are complex and difficult to analyze in that they have the problems associated with conventional rotors plus those additional problems associated with the gear couplings. This paper examines the problems peculiar to the gear mesh. Because of the meshing action of gears, the elasticity of the gear teeth introduces time-varying stiffness coefficients into the governing equations of motion. This means that system response must be thought of in terms of Mathieu-type equations, where multiple-frequency response occur due to the periodic coefficients. The meshing action of the gears also couples the lateral and torsional gear motions. Gear errors, such as tooth profile and spacing errors, produce forces and torque that excite the system at multiple frequencies, some of which are much higher than shaft rotational speed. To investigate how to the time-varying stiffness in the gear teeth and the gear errors act one the dynamic response of the gear coupled rotors, a three-dimensional dynamic model with lateral-tortional oscillation is developed. The harmonic balance technique is employed to solve this mathieu-type problem.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.661-666
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• 2004

The purpose of this study is to measure the rotational vibration, radial vibration, and axial vibration for the helical gear with the wide face width relative to the whole depth. For this purpose, the experimental apparatus is designed and manufactured. The gear vibration of each direction is measured by the accelerometers attached at the gear body. As a result, meshing frequency and second harmonic component are greatly contributed to the gear vibration. As the rotational speed is increased, meshing frequency component has the more significant peak than the second harmonic one. However, the doubled torque decreases the vibration magnitude on the contrary and changes order of the vibration magnitude in each direction.

• Tribology and Lubricants
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• 제5권2호
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• pp.107-112
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• 1989

This paper deals with strength analysis of tooth and method of manufacture of external tooth profile in harmonic drive. From the calculation of load imposed on the contact teeth, moximum contact stress is investigated to design the addendum modification coefficient. New tooth profile of the external gear is generated according to the law of gearing, assuming that internal gear has involute tooth profile. External tooth profile can't be manufactured by conventional exclusive tools which have pressure angle of 20$\circ$. The method to design cutter tooth profile is presented.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.726-733
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• 2017

마그네틱 셔터 기어는 원주상에 마주하는 영구자석 레이어간의 자기장을 고조파 모듈레이터를 통해 동기화시켜 동력을 전달하는 장치이다. 이러한 장치는 기계식 감속기에 필적할만한 토크를 발생시키기 위해 과다한 희토류 영구자석이 이용되기 때문에 본 논문에서는 영구자석간의 자기 경로를 변화시켜 영구자석의 양을 기존 마그네틱 기어 대비 50% 수준으로 감소시킨 새로운 방식의 축형 마그네틱 기어를 제안한다. 제안한 시스템의 토크 크기는 공극 자기장의 고조파 분석과 유한 요소 해석을 통해 기존 시스템과 비교된다. 모듈레이터 두께와 개방비가 전달 토크의 크기에 영향을 미치는 주요 설계변수로 고려되어 민감도 해석이 수행되며 고속측과 저속측의 영구자석 극수에 의해 결정되는 기어비에 따른 코깅의 크기가 분석된다. 기계적인 접촉없이 커플링되어 동력을 전달하는 고속측과 저속측 사이의 동적 지배 모델이 유도된다. 2관성 공진계의 동특성을 갖는 유도된 모델을 기초로 하여 선형 제어기를 설계하여 고속측의 계단 입력 위치 제어를 수행하였다.